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-rw-r--r--Documentation/arch/x86/index.rst1
-rw-r--r--Documentation/arch/x86/shstk.rst179
-rw-r--r--Documentation/filesystems/proc.rst1
-rw-r--r--Documentation/mm/arch_pgtable_helpers.rst12
-rw-r--r--arch/Kconfig8
-rw-r--r--arch/alpha/include/asm/pgtable.h2
-rw-r--r--arch/arc/include/asm/hugepage.h2
-rw-r--r--arch/arc/include/asm/pgtable-bits-arcv2.h2
-rw-r--r--arch/arm/include/asm/pgtable-3level.h2
-rw-r--r--arch/arm/include/asm/pgtable.h2
-rw-r--r--arch/arm/kernel/signal.c2
-rw-r--r--arch/arm64/include/asm/pgtable.h4
-rw-r--r--arch/arm64/kernel/signal.c2
-rw-r--r--arch/arm64/kernel/signal32.c2
-rw-r--r--arch/arm64/mm/trans_pgd.c4
-rw-r--r--arch/csky/include/asm/pgtable.h2
-rw-r--r--arch/hexagon/include/asm/pgtable.h2
-rw-r--r--arch/ia64/include/asm/pgtable.h2
-rw-r--r--arch/loongarch/include/asm/pgtable.h4
-rw-r--r--arch/m68k/include/asm/mcf_pgtable.h2
-rw-r--r--arch/m68k/include/asm/motorola_pgtable.h2
-rw-r--r--arch/m68k/include/asm/sun3_pgtable.h2
-rw-r--r--arch/microblaze/include/asm/pgtable.h2
-rw-r--r--arch/mips/include/asm/pgtable.h6
-rw-r--r--arch/nios2/include/asm/pgtable.h2
-rw-r--r--arch/openrisc/include/asm/pgtable.h2
-rw-r--r--arch/parisc/include/asm/pgtable.h2
-rw-r--r--arch/powerpc/include/asm/book3s/32/pgtable.h2
-rw-r--r--arch/powerpc/include/asm/book3s/64/pgtable.h4
-rw-r--r--arch/powerpc/include/asm/nohash/32/pgtable.h4
-rw-r--r--arch/powerpc/include/asm/nohash/32/pte-8xx.h4
-rw-r--r--arch/powerpc/include/asm/nohash/64/pgtable.h2
-rw-r--r--arch/riscv/include/asm/pgtable.h6
-rw-r--r--arch/s390/Kconfig1
-rw-r--r--arch/s390/include/asm/hugetlb.h2
-rw-r--r--arch/s390/include/asm/pgtable.h4
-rw-r--r--arch/s390/mm/pageattr.c4
-rw-r--r--arch/sh/include/asm/pgtable_32.h4
-rw-r--r--arch/sparc/include/asm/pgtable_32.h2
-rw-r--r--arch/sparc/include/asm/pgtable_64.h6
-rw-r--r--arch/sparc/kernel/signal32.c2
-rw-r--r--arch/sparc/kernel/signal_64.c2
-rw-r--r--arch/um/include/asm/pgtable.h2
-rw-r--r--arch/x86/Kconfig24
-rw-r--r--arch/x86/Kconfig.assembler5
-rw-r--r--arch/x86/entry/syscalls/syscall_64.tbl1
-rw-r--r--arch/x86/include/asm/cpufeatures.h2
-rw-r--r--arch/x86/include/asm/disabled-features.h16
-rw-r--r--arch/x86/include/asm/fpu/api.h9
-rw-r--r--arch/x86/include/asm/fpu/regset.h7
-rw-r--r--arch/x86/include/asm/fpu/sched.h3
-rw-r--r--arch/x86/include/asm/fpu/types.h16
-rw-r--r--arch/x86/include/asm/fpu/xstate.h6
-rw-r--r--arch/x86/include/asm/idtentry.h2
-rw-r--r--arch/x86/include/asm/mmu_context.h2
-rw-r--r--arch/x86/include/asm/pgtable.h302
-rw-r--r--arch/x86/include/asm/pgtable_types.h44
-rw-r--r--arch/x86/include/asm/processor.h8
-rw-r--r--arch/x86/include/asm/shstk.h38
-rw-r--r--arch/x86/include/asm/special_insns.h13
-rw-r--r--arch/x86/include/asm/tlbflush.h3
-rw-r--r--arch/x86/include/asm/trap_pf.h2
-rw-r--r--arch/x86/include/asm/traps.h15
-rw-r--r--arch/x86/include/uapi/asm/mman.h4
-rw-r--r--arch/x86/include/uapi/asm/prctl.h12
-rw-r--r--arch/x86/kernel/Makefile5
-rw-r--r--arch/x86/kernel/cet.c131
-rw-r--r--arch/x86/kernel/cpu/common.c35
-rw-r--r--arch/x86/kernel/cpu/cpuid-deps.c1
-rw-r--r--arch/x86/kernel/cpu/proc.c23
-rw-r--r--arch/x86/kernel/fpu/core.c54
-rw-r--r--arch/x86/kernel/fpu/regset.c81
-rw-r--r--arch/x86/kernel/fpu/xstate.c90
-rw-r--r--arch/x86/kernel/ibt_selftest.S17
-rw-r--r--arch/x86/kernel/idt.c2
-rw-r--r--arch/x86/kernel/process.c21
-rw-r--r--arch/x86/kernel/process_64.c8
-rw-r--r--arch/x86/kernel/ptrace.c12
-rw-r--r--arch/x86/kernel/shstk.c550
-rw-r--r--arch/x86/kernel/signal.c1
-rw-r--r--arch/x86/kernel/signal_32.c2
-rw-r--r--arch/x86/kernel/signal_64.c8
-rw-r--r--arch/x86/kernel/sys_x86_64.c6
-rw-r--r--arch/x86/kernel/traps.c87
-rw-r--r--arch/x86/mm/fault.c22
-rw-r--r--arch/x86/mm/pat/set_memory.c4
-rw-r--r--arch/x86/mm/pgtable.c40
-rw-r--r--arch/x86/xen/enlighten_pv.c2
-rw-r--r--arch/x86/xen/mmu_pv.c2
-rw-r--r--arch/x86/xen/xen-asm.S2
-rw-r--r--arch/xtensa/include/asm/pgtable.h2
-rw-r--r--fs/aio.c2
-rw-r--r--fs/proc/array.c6
-rw-r--r--fs/proc/task_mmu.c3
-rw-r--r--include/asm-generic/hugetlb.h2
-rw-r--r--include/linux/mm.h47
-rw-r--r--include/linux/mman.h4
-rw-r--r--include/linux/pgtable.h28
-rw-r--r--include/linux/proc_fs.h1
-rw-r--r--include/linux/syscalls.h1
-rw-r--r--include/uapi/asm-generic/siginfo.h3
-rw-r--r--include/uapi/linux/elf.h2
-rw-r--r--ipc/shm.c2
-rw-r--r--kernel/sys_ni.c1
-rw-r--r--mm/debug_vm_pgtable.c12
-rw-r--r--mm/gup.c2
-rw-r--r--mm/huge_memory.c11
-rw-r--r--mm/internal.h4
-rw-r--r--mm/memory.c5
-rw-r--r--mm/migrate.c2
-rw-r--r--mm/migrate_device.c2
-rw-r--r--mm/mmap.c14
-rw-r--r--mm/mprotect.c2
-rw-r--r--mm/nommu.c4
-rw-r--r--mm/userfaultfd.c2
-rw-r--r--mm/util.c2
-rw-r--r--tools/testing/selftests/x86/Makefile2
-rw-r--r--tools/testing/selftests/x86/test_shadow_stack.c884
118 files changed, 2790 insertions, 308 deletions
diff --git a/Documentation/arch/x86/index.rst b/Documentation/arch/x86/index.rst
index c73d133fd37c..8ac64d7de4dc 100644
--- a/Documentation/arch/x86/index.rst
+++ b/Documentation/arch/x86/index.rst
@@ -22,6 +22,7 @@ x86-specific Documentation
mtrr
pat
intel-hfi
+ shstk
iommu
intel_txt
amd-memory-encryption
diff --git a/Documentation/arch/x86/shstk.rst b/Documentation/arch/x86/shstk.rst
new file mode 100644
index 000000000000..60260e809baf
--- /dev/null
+++ b/Documentation/arch/x86/shstk.rst
@@ -0,0 +1,179 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================================
+Control-flow Enforcement Technology (CET) Shadow Stack
+======================================================
+
+CET Background
+==============
+
+Control-flow Enforcement Technology (CET) covers several related x86 processor
+features that provide protection against control flow hijacking attacks. CET
+can protect both applications and the kernel.
+
+CET introduces shadow stack and indirect branch tracking (IBT). A shadow stack
+is a secondary stack allocated from memory which cannot be directly modified by
+applications. When executing a CALL instruction, the processor pushes the
+return address to both the normal stack and the shadow stack. Upon
+function return, the processor pops the shadow stack copy and compares it
+to the normal stack copy. If the two differ, the processor raises a
+control-protection fault. IBT verifies indirect CALL/JMP targets are intended
+as marked by the compiler with 'ENDBR' opcodes. Not all CPU's have both Shadow
+Stack and Indirect Branch Tracking. Today in the 64-bit kernel, only userspace
+shadow stack and kernel IBT are supported.
+
+Requirements to use Shadow Stack
+================================
+
+To use userspace shadow stack you need HW that supports it, a kernel
+configured with it and userspace libraries compiled with it.
+
+The kernel Kconfig option is X86_USER_SHADOW_STACK. When compiled in, shadow
+stacks can be disabled at runtime with the kernel parameter: nousershstk.
+
+To build a user shadow stack enabled kernel, Binutils v2.29 or LLVM v6 or later
+are required.
+
+At run time, /proc/cpuinfo shows CET features if the processor supports
+CET. "user_shstk" means that userspace shadow stack is supported on the current
+kernel and HW.
+
+Application Enabling
+====================
+
+An application's CET capability is marked in its ELF note and can be verified
+from readelf/llvm-readelf output::
+
+ readelf -n <application> | grep -a SHSTK
+ properties: x86 feature: SHSTK
+
+The kernel does not process these applications markers directly. Applications
+or loaders must enable CET features using the interface described in section 4.
+Typically this would be done in dynamic loader or static runtime objects, as is
+the case in GLIBC.
+
+Enabling arch_prctl()'s
+=======================
+
+Elf features should be enabled by the loader using the below arch_prctl's. They
+are only supported in 64 bit user applications. These operate on the features
+on a per-thread basis. The enablement status is inherited on clone, so if the
+feature is enabled on the first thread, it will propagate to all the thread's
+in an app.
+
+arch_prctl(ARCH_SHSTK_ENABLE, unsigned long feature)
+ Enable a single feature specified in 'feature'. Can only operate on
+ one feature at a time.
+
+arch_prctl(ARCH_SHSTK_DISABLE, unsigned long feature)
+ Disable a single feature specified in 'feature'. Can only operate on
+ one feature at a time.
+
+arch_prctl(ARCH_SHSTK_LOCK, unsigned long features)
+ Lock in features at their current enabled or disabled status. 'features'
+ is a mask of all features to lock. All bits set are processed, unset bits
+ are ignored. The mask is ORed with the existing value. So any feature bits
+ set here cannot be enabled or disabled afterwards.
+
+arch_prctl(ARCH_SHSTK_UNLOCK, unsigned long features)
+ Unlock features. 'features' is a mask of all features to unlock. All
+ bits set are processed, unset bits are ignored. Only works via ptrace.
+
+arch_prctl(ARCH_SHSTK_STATUS, unsigned long addr)
+ Copy the currently enabled features to the address passed in addr. The
+ features are described using the bits passed into the others in
+ 'features'.
+
+The return values are as follows. On success, return 0. On error, errno can
+be::
+
+ -EPERM if any of the passed feature are locked.
+ -ENOTSUPP if the feature is not supported by the hardware or
+ kernel.
+ -EINVAL arguments (non existing feature, etc)
+ -EFAULT if could not copy information back to userspace
+
+The feature's bits supported are::
+
+ ARCH_SHSTK_SHSTK - Shadow stack
+ ARCH_SHSTK_WRSS - WRSS
+
+Currently shadow stack and WRSS are supported via this interface. WRSS
+can only be enabled with shadow stack, and is automatically disabled
+if shadow stack is disabled.
+
+Proc Status
+===========
+To check if an application is actually running with shadow stack, the
+user can read the /proc/$PID/status. It will report "wrss" or "shstk"
+depending on what is enabled. The lines look like this::
+
+ x86_Thread_features: shstk wrss
+ x86_Thread_features_locked: shstk wrss
+
+Implementation of the Shadow Stack
+==================================
+
+Shadow Stack Size
+-----------------
+
+A task's shadow stack is allocated from memory to a fixed size of
+MIN(RLIMIT_STACK, 4 GB). In other words, the shadow stack is allocated to
+the maximum size of the normal stack, but capped to 4 GB. In the case
+of the clone3 syscall, there is a stack size passed in and shadow stack
+uses this instead of the rlimit.
+
+Signal
+------
+
+The main program and its signal handlers use the same shadow stack. Because
+the shadow stack stores only return addresses, a large shadow stack covers
+the condition that both the program stack and the signal alternate stack run
+out.
+
+When a signal happens, the old pre-signal state is pushed on the stack. When
+shadow stack is enabled, the shadow stack specific state is pushed onto the
+shadow stack. Today this is only the old SSP (shadow stack pointer), pushed
+in a special format with bit 63 set. On sigreturn this old SSP token is
+verified and restored by the kernel. The kernel will also push the normal
+restorer address to the shadow stack to help userspace avoid a shadow stack
+violation on the sigreturn path that goes through the restorer.
+
+So the shadow stack signal frame format is as follows::
+
+ |1...old SSP| - Pointer to old pre-signal ssp in sigframe token format
+ (bit 63 set to 1)
+ | ...| - Other state may be added in the future
+
+
+32 bit ABI signals are not supported in shadow stack processes. Linux prevents
+32 bit execution while shadow stack is enabled by the allocating shadow stacks
+outside of the 32 bit address space. When execution enters 32 bit mode, either
+via far call or returning to userspace, a #GP is generated by the hardware
+which, will be delivered to the process as a segfault. When transitioning to
+userspace the register's state will be as if the userspace ip being returned to
+caused the segfault.
+
+Fork
+----
+
+The shadow stack's vma has VM_SHADOW_STACK flag set; its PTEs are required
+to be read-only and dirty. When a shadow stack PTE is not RO and dirty, a
+shadow access triggers a page fault with the shadow stack access bit set
+in the page fault error code.
+
+When a task forks a child, its shadow stack PTEs are copied and both the
+parent's and the child's shadow stack PTEs are cleared of the dirty bit.
+Upon the next shadow stack access, the resulting shadow stack page fault
+is handled by page copy/re-use.
+
+When a pthread child is created, the kernel allocates a new shadow stack
+for the new thread. New shadow stack creation behaves like mmap() with respect
+to ASLR behavior. Similarly, on thread exit the thread's shadow stack is
+disabled.
+
+Exec
+----
+
+On exec, shadow stack features are disabled by the kernel. At which point,
+userspace can choose to re-enable, or lock them.
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index d6109c78a228..1f9615553b82 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -566,6 +566,7 @@ encoded manner. The codes are the following:
mt arm64 MTE allocation tags are enabled
um userfaultfd missing tracking
uw userfaultfd wr-protect tracking
+ ss shadow stack page
== =======================================
Note that there is no guarantee that every flag and associated mnemonic will
diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst
index af3891f895b0..c82e3ee20e51 100644
--- a/Documentation/mm/arch_pgtable_helpers.rst
+++ b/Documentation/mm/arch_pgtable_helpers.rst
@@ -46,7 +46,11 @@ PTE Page Table Helpers
+---------------------------+--------------------------------------------------+
| pte_mkclean | Creates a clean PTE |
+---------------------------+--------------------------------------------------+
-| pte_mkwrite | Creates a writable PTE |
+| pte_mkwrite | Creates a writable PTE of the type specified by |
+| | the VMA. |
++---------------------------+--------------------------------------------------+
+| pte_mkwrite_novma | Creates a writable PTE, of the conventional type |
+| | of writable. |
+---------------------------+--------------------------------------------------+
| pte_wrprotect | Creates a write protected PTE |
+---------------------------+--------------------------------------------------+
@@ -118,7 +122,11 @@ PMD Page Table Helpers
+---------------------------+--------------------------------------------------+
| pmd_mkclean | Creates a clean PMD |
+---------------------------+--------------------------------------------------+
-| pmd_mkwrite | Creates a writable PMD |
+| pmd_mkwrite | Creates a writable PMD of the type specified by |
+| | the VMA. |
++---------------------------+--------------------------------------------------+
+| pmd_mkwrite_novma | Creates a writable PMD, of the conventional type |
+| | of writable. |
+---------------------------+--------------------------------------------------+
| pmd_wrprotect | Creates a write protected PMD |
+---------------------------+--------------------------------------------------+
diff --git a/arch/Kconfig b/arch/Kconfig
index ec49c0100550..12d51495caec 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -931,6 +931,14 @@ config HAVE_ARCH_HUGE_VMALLOC
config ARCH_WANT_HUGE_PMD_SHARE
bool
+# Archs that want to use pmd_mkwrite on kernel memory need it defined even
+# if there are no userspace memory management features that use it
+config ARCH_WANT_KERNEL_PMD_MKWRITE
+ bool
+
+config ARCH_WANT_PMD_MKWRITE
+ def_bool TRANSPARENT_HUGEPAGE || ARCH_WANT_KERNEL_PMD_MKWRITE
+
config HAVE_ARCH_SOFT_DIRTY
bool
diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 747b5f706c47..635f0a5f5bbd 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h
@@ -256,7 +256,7 @@ extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED;
extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
-extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
+extern inline pte_t pte_mkwrite_novma(pte_t pte){ pte_val(pte) &= ~_PAGE_FOW; return pte; }
extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
diff --git a/arch/arc/include/asm/hugepage.h b/arch/arc/include/asm/hugepage.h
index 5001b796fb8d..ef8d4166370c 100644
--- a/arch/arc/include/asm/hugepage.h
+++ b/arch/arc/include/asm/hugepage.h
@@ -21,7 +21,7 @@ static inline pmd_t pte_pmd(pte_t pte)
}
#define pmd_wrprotect(pmd) pte_pmd(pte_wrprotect(pmd_pte(pmd)))
-#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+#define pmd_mkwrite_novma(pmd) pte_pmd(pte_mkwrite_novma(pmd_pte(pmd)))
#define pmd_mkdirty(pmd) pte_pmd(pte_mkdirty(pmd_pte(pmd)))
#define pmd_mkold(pmd) pte_pmd(pte_mkold(pmd_pte(pmd)))
#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
diff --git a/arch/arc/include/asm/pgtable-bits-arcv2.h b/arch/arc/include/asm/pgtable-bits-arcv2.h
index ee78ab30958d..f3eea3f30b2e 100644
--- a/arch/arc/include/asm/pgtable-bits-arcv2.h
+++ b/arch/arc/include/asm/pgtable-bits-arcv2.h
@@ -87,7 +87,7 @@
PTE_BIT_FUNC(mknotpresent, &= ~(_PAGE_PRESENT));
PTE_BIT_FUNC(wrprotect, &= ~(_PAGE_WRITE));
-PTE_BIT_FUNC(mkwrite, |= (_PAGE_WRITE));
+PTE_BIT_FUNC(mkwrite_novma, |= (_PAGE_WRITE));
PTE_BIT_FUNC(mkclean, &= ~(_PAGE_DIRTY));
PTE_BIT_FUNC(mkdirty, |= (_PAGE_DIRTY));
PTE_BIT_FUNC(mkold, &= ~(_PAGE_ACCESSED));
diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 106049791500..71c3add6417f 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h
@@ -202,7 +202,7 @@ static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }
PMD_BIT_FUNC(wrprotect, |= L_PMD_SECT_RDONLY);
PMD_BIT_FUNC(mkold, &= ~PMD_SECT_AF);
-PMD_BIT_FUNC(mkwrite, &= ~L_PMD_SECT_RDONLY);
+PMD_BIT_FUNC(mkwrite_novma, &= ~L_PMD_SECT_RDONLY);
PMD_BIT_FUNC(mkdirty, |= L_PMD_SECT_DIRTY);
PMD_BIT_FUNC(mkclean, &= ~L_PMD_SECT_DIRTY);
PMD_BIT_FUNC(mkyoung, |= PMD_SECT_AF);
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index ba573f22d7cc..16b02f44c7d3 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -228,7 +228,7 @@ static inline pte_t pte_wrprotect(pte_t pte)
return set_pte_bit(pte, __pgprot(L_PTE_RDONLY));
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return clear_pte_bit(pte, __pgprot(L_PTE_RDONLY));
}
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 8d0afa11bed5..79a6730fa0eb 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -682,7 +682,7 @@ asmlinkage void do_rseq_syscall(struct pt_regs *regs)
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 432932ad087f..7f7d9b1df4e5 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -181,7 +181,7 @@ static inline pmd_t set_pmd_bit(pmd_t pmd, pgprot_t prot)
return pmd;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte = set_pte_bit(pte, __pgprot(PTE_WRITE));
pte = clear_pte_bit(pte, __pgprot(PTE_RDONLY));
@@ -487,7 +487,7 @@ static inline int pmd_trans_huge(pmd_t pmd)
#define pmd_cont(pmd) pte_cont(pmd_pte(pmd))
#define pmd_wrprotect(pmd) pte_pmd(pte_wrprotect(pmd_pte(pmd)))
#define pmd_mkold(pmd) pte_pmd(pte_mkold(pmd_pte(pmd)))
-#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+#define pmd_mkwrite_novma(pmd) pte_pmd(pte_mkwrite_novma(pmd_pte(pmd)))
#define pmd_mkclean(pmd) pte_pmd(pte_mkclean(pmd_pte(pmd)))
#define pmd_mkdirty(pmd) pte_pmd(pte_mkdirty(pmd_pte(pmd)))
#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index c7ebe744c64e..0e8beb3349ea 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -1344,7 +1344,7 @@ void __init minsigstksz_setup(void)
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 4700f8522d27..bbd542704730 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -460,7 +460,7 @@ void compat_setup_restart_syscall(struct pt_regs *regs)
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index e9ad391fc8ea..7b14df3c6477 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -41,7 +41,7 @@ static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
* read only (code, rodata). Clear the RDONLY bit from
* the temporary mappings we use during restore.
*/
- set_pte(dst_ptep, pte_mkwrite(pte));
+ set_pte(dst_ptep, pte_mkwrite_novma(pte));
} else if ((debug_pagealloc_enabled() ||
is_kfence_address((void *)addr)) && !pte_none(pte)) {
/*
@@ -55,7 +55,7 @@ static void _copy_pte(pte_t *dst_ptep, pte_t *src_ptep, unsigned long addr)
*/
BUG_ON(!pfn_valid(pte_pfn(pte)));
- set_pte(dst_ptep, pte_mkpresent(pte_mkwrite(pte)));
+ set_pte(dst_ptep, pte_mkpresent(pte_mkwrite_novma(pte)));
}
}
diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index 42405037c871..a397e1718ab6 100644
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h
@@ -176,7 +176,7 @@ static inline pte_t pte_mkold(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
if (pte_val(pte) & _PAGE_MODIFIED)
diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
index dd05dd71b8ec..8c5b7a1c3d90 100644
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h
@@ -300,7 +300,7 @@ static inline pte_t pte_wrprotect(pte_t pte)
}
/* pte_mkwrite - mark page as writable */
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
return pte;
diff --git a/arch/ia64/include/asm/pgtable.h b/arch/ia64/include/asm/pgtable.h
index 4e5dd800ce1f..9be2d2ba6016 100644
--- a/arch/ia64/include/asm/pgtable.h
+++ b/arch/ia64/include/asm/pgtable.h
@@ -269,7 +269,7 @@ ia64_phys_addr_valid (unsigned long addr)
* access rights:
*/
#define pte_wrprotect(pte) (__pte(pte_val(pte) & ~_PAGE_AR_RW))
-#define pte_mkwrite(pte) (__pte(pte_val(pte) | _PAGE_AR_RW))
+#define pte_mkwrite_novma(pte) (__pte(pte_val(pte) | _PAGE_AR_RW))
#define pte_mkold(pte) (__pte(pte_val(pte) & ~_PAGE_A))
#define pte_mkyoung(pte) (__pte(pte_val(pte) | _PAGE_A))
#define pte_mkclean(pte) (__pte(pte_val(pte) & ~_PAGE_D))
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index e7cf25e452c0..06963a172319 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -384,7 +384,7 @@ static inline pte_t pte_mkdirty(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
if (pte_val(pte) & _PAGE_MODIFIED)
@@ -493,7 +493,7 @@ static inline int pmd_write(pmd_t pmd)
return !!(pmd_val(pmd) & _PAGE_WRITE);
}
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
{
pmd_val(pmd) |= _PAGE_WRITE;
if (pmd_val(pmd) & _PAGE_MODIFIED)
diff --git a/arch/m68k/include/asm/mcf_pgtable.h b/arch/m68k/include/asm/mcf_pgtable.h
index 772b7e7b0654..48f87a8a8832 100644
--- a/arch/m68k/include/asm/mcf_pgtable.h
+++ b/arch/m68k/include/asm/mcf_pgtable.h
@@ -210,7 +210,7 @@ static inline pte_t pte_mkold(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= CF_PAGE_WRITABLE;
return pte;
diff --git a/arch/m68k/include/asm/motorola_pgtable.h b/arch/m68k/include/asm/motorola_pgtable.h
index 38d5e5edc3e1..9866c7acdabe 100644
--- a/arch/m68k/include/asm/motorola_pgtable.h
+++ b/arch/m68k/include/asm/motorola_pgtable.h
@@ -156,7 +156,7 @@ static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED;
static inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_RONLY; return pte; }
static inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~_PAGE_DIRTY; return pte; }
static inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
-static inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_RONLY; return pte; }
+static inline pte_t pte_mkwrite_novma(pte_t pte){ pte_val(pte) &= ~_PAGE_RONLY; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
static inline pte_t pte_mknocache(pte_t pte)
diff --git a/arch/m68k/include/asm/sun3_pgtable.h b/arch/m68k/include/asm/sun3_pgtable.h
index 0cc39a88ce55..30081aee8164 100644
--- a/arch/m68k/include/asm/sun3_pgtable.h
+++ b/arch/m68k/include/asm/sun3_pgtable.h
@@ -144,7 +144,7 @@ static inline int pte_young(pte_t pte) { return pte_val(pte) & SUN3_PAGE_ACCESS
static inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) &= ~SUN3_PAGE_WRITEABLE; return pte; }
static inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~SUN3_PAGE_MODIFIED; return pte; }
static inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~SUN3_PAGE_ACCESSED; return pte; }
-static inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) |= SUN3_PAGE_WRITEABLE; return pte; }
+static inline pte_t pte_mkwrite_novma(pte_t pte){ pte_val(pte) |= SUN3_PAGE_WRITEABLE; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= SUN3_PAGE_MODIFIED; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= SUN3_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mknocache(pte_t pte) { pte_val(pte) |= SUN3_PAGE_NOCACHE; return pte; }
diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index 6f9b99082518..3042eb98bb56 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h
@@ -266,7 +266,7 @@ static inline pte_t pte_mkread(pte_t pte) \
{ pte_val(pte) |= _PAGE_USER; return pte; }
static inline pte_t pte_mkexec(pte_t pte) \
{ pte_val(pte) |= _PAGE_USER | _PAGE_EXEC; return pte; }
-static inline pte_t pte_mkwrite(pte_t pte) \
+static inline pte_t pte_mkwrite_novma(pte_t pte) \
{ pte_val(pte) |= _PAGE_RW; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) \
{ pte_val(pte) |= _PAGE_DIRTY; return pte; }
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index cbb93a834f52..430b208c0130 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -319,7 +319,7 @@ static inline pte_t pte_mkold(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte.pte_low |= _PAGE_WRITE;
if (pte.pte_low & _PAGE_MODIFIED) {
@@ -374,7 +374,7 @@ static inline pte_t pte_mkold(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
if (pte_val(pte) & _PAGE_MODIFIED)
@@ -646,7 +646,7 @@ static inline pmd_t pmd_wrprotect(pmd_t pmd)
return pmd;
}
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
{
pmd_val(pmd) |= _PAGE_WRITE;
if (pmd_val(pmd) & _PAGE_MODIFIED)
diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index be6bf3e0bd7a..5144506dfa69 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h
@@ -129,7 +129,7 @@ static inline pte_t pte_mkold(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
return pte;
diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index 7bdf1bb0d177..60c6ce7ff2dc 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h
@@ -250,7 +250,7 @@ static inline pte_t pte_mkold(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte_val(pte) |= _PAGE_WRITE;
return pte;
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index ce38bb375b60..974accac05cd 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -322,7 +322,7 @@ static inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~_PAGE_ACCESSED; retu
static inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) &= ~_PAGE_WRITE; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
-static inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) |= _PAGE_WRITE; return pte; }
+static inline pte_t pte_mkwrite_novma(pte_t pte) { pte_val(pte) |= _PAGE_WRITE; return pte; }
static inline pte_t pte_mkspecial(pte_t pte) { pte_val(pte) |= _PAGE_SPECIAL; return pte; }
/*
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 5f12b9382909..86650d13ebe6 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -493,7 +493,7 @@ static inline pte_t pte_mkpte(pte_t pte)
return pte;
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_RW);
}
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 8269b231c533..136232a89739 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -596,7 +596,7 @@ static inline pte_t pte_mkexec(pte_t pte)
return __pte_raw(pte_raw(pte) | cpu_to_be64(_PAGE_EXEC));
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
/*
* write implies read, hence set both
@@ -1088,7 +1088,7 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd)
#define pmd_mkdirty(pmd) pte_pmd(pte_mkdirty(pmd_pte(pmd)))
#define pmd_mkclean(pmd) pte_pmd(pte_mkclean(pmd_pte(pmd)))
#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
-#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+#define pmd_mkwrite_novma(pmd) pte_pmd(pte_mkwrite_novma(pmd_pte(pmd)))
#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
#define pmd_soft_dirty(pmd) pte_soft_dirty(pmd_pte(pmd))
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index fec56d965f00..33213b31fcbb 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -170,8 +170,8 @@ void unmap_kernel_page(unsigned long va);
#define pte_clear(mm, addr, ptep) \
do { pte_update(mm, addr, ptep, ~0, 0, 0); } while (0)
-#ifndef pte_mkwrite
-static inline pte_t pte_mkwrite(pte_t pte)
+#ifndef pte_mkwrite_novma
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_RW);
}
diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
index 1a89ebdc3acc..21f681ee535a 100644
--- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
@@ -101,12 +101,12 @@ static inline int pte_write(pte_t pte)
#define pte_write pte_write
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) & ~_PAGE_RO);
}
-#define pte_mkwrite pte_mkwrite
+#define pte_mkwrite_novma pte_mkwrite_novma
static inline bool pte_user(pte_t pte)
{
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index 287e25864ffa..abe4fd82721e 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -85,7 +85,7 @@
#ifndef __ASSEMBLY__
/* pte_clear moved to later in this file */
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_RW);
}
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index a6f47c092bdc..2f1c0cde2ca4 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -380,7 +380,7 @@ static inline pte_t pte_wrprotect(pte_t pte)
/* static inline pte_t pte_mkread(pte_t pte) */
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_WRITE);
}
@@ -677,9 +677,9 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
return pte_pmd(pte_mkyoung(pmd_pte(pmd)));
}
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
{
- return pte_pmd(pte_mkwrite(pmd_pte(pmd)));
+ return pte_pmd(pte_mkwrite_novma(pmd_pte(pmd)));
}
static inline pmd_t pmd_wrprotect(pmd_t pmd)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 661b6de69c27..ae29e4392664 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -127,6 +127,7 @@ config S390
select ARCH_WANTS_NO_INSTR
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_KERNEL_PMD_MKWRITE
select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
select BUILDTIME_TABLE_SORT
select CLONE_BACKWARDS2
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index ccdbccfde148..f07267875a19 100644
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -104,7 +104,7 @@ static inline int huge_pte_dirty(pte_t pte)
static inline pte_t huge_pte_mkwrite(pte_t pte)
{
- return pte_mkwrite(pte);
+ return pte_mkwrite_novma(pte);
}
static inline pte_t huge_pte_mkdirty(pte_t pte)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index d28d2e5e68ee..fb3ee7758b76 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1001,7 +1001,7 @@ static inline pte_t pte_wrprotect(pte_t pte)
return set_pte_bit(pte, __pgprot(_PAGE_PROTECT));
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
pte = set_pte_bit(pte, __pgprot(_PAGE_WRITE));
if (pte_val(pte) & _PAGE_DIRTY)
@@ -1498,7 +1498,7 @@ static inline pmd_t pmd_wrprotect(pmd_t pmd)
return set_pmd_bit(pmd, __pgprot(_SEGMENT_ENTRY_PROTECT));
}
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
{
pmd = set_pmd_bit(pmd, __pgprot(_SEGMENT_ENTRY_WRITE));
if (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY)
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c
index ca5a418c58a8..e5ec76271b16 100644
--- a/arch/s390/mm/pageattr.c
+++ b/arch/s390/mm/pageattr.c
@@ -98,7 +98,7 @@ static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
if (flags & SET_MEMORY_RO)
new = pte_wrprotect(new);
else if (flags & SET_MEMORY_RW)
- new = pte_mkwrite(pte_mkdirty(new));
+ new = pte_mkwrite_novma(pte_mkdirty(new));
if (flags & SET_MEMORY_NX)
new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
else if (flags & SET_MEMORY_X)
@@ -156,7 +156,7 @@ static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
if (flags & SET_MEMORY_RO)
new = pmd_wrprotect(new);
else if (flags & SET_MEMORY_RW)
- new = pmd_mkwrite(pmd_mkdirty(new));
+ new = pmd_mkwrite_novma(pmd_mkdirty(new));
if (flags & SET_MEMORY_NX)
new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
else if (flags & SET_MEMORY_X)
diff --git a/arch/sh/include/asm/pgtable_32.h b/arch/sh/include/asm/pgtable_32.h
index 676f3d4ef6ce..f939f1215232 100644
--- a/arch/sh/include/asm/pgtable_32.h
+++ b/arch/sh/include/asm/pgtable_32.h
@@ -358,11 +358,11 @@ static inline pte_t pte_##fn(pte_t pte) { pte.pte_##h op; return pte; }
* kernel permissions), we attempt to couple them a bit more sanely here.
*/
PTE_BIT_FUNC(high, wrprotect, &= ~(_PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE));
-PTE_BIT_FUNC(high, mkwrite, |= _PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE);
+PTE_BIT_FUNC(high, mkwrite_novma, |= _PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE);
PTE_BIT_FUNC(high, mkhuge, |= _PAGE_SZHUGE);
#else
PTE_BIT_FUNC(low, wrprotect, &= ~_PAGE_RW);
-PTE_BIT_FUNC(low, mkwrite, |= _PAGE_RW);
+PTE_BIT_FUNC(low, mkwrite_novma, |= _PAGE_RW);
PTE_BIT_FUNC(low, mkhuge, |= _PAGE_SZHUGE);
#endif
diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 315d316614ca..9e85d57ac3f2 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -239,7 +239,7 @@ static inline pte_t pte_mkold(pte_t pte)
return __pte(pte_val(pte) & ~SRMMU_REF);
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return __pte(pte_val(pte) | SRMMU_WRITE);
}
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 09aa37cc4469..5e41033bf4ca 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -518,7 +518,7 @@ static inline pte_t pte_mkclean(pte_t pte)
return __pte(val);
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
unsigned long val = pte_val(pte), mask;
@@ -773,11 +773,11 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
return __pmd(pte_val(pte));
}
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
{
pte_t pte = __pte(pmd_val(pmd));
- pte = pte_mkwrite(pte);
+ pte = pte_mkwrite_novma(pte);
return __pmd(pte_val(pte));
}
diff --git a/arch/sparc/kernel/signal32.c b/arch/sparc/kernel/signal32.c
index ca450c7bc53f..a23cdd7459bb 100644
--- a/arch/sparc/kernel/signal32.c
+++ b/arch/sparc/kernel/signal32.c
@@ -753,7 +753,7 @@ out:
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/sparc/kernel/signal_64.c b/arch/sparc/kernel/signal_64.c
index 570e43e6fda5..b4e410976e0d 100644
--- a/arch/sparc/kernel/signal_64.c
+++ b/arch/sparc/kernel/signal_64.c
@@ -562,7 +562,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 44f6c76167d9..e1ece21dbe3f 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -207,7 +207,7 @@ static inline pte_t pte_mkyoung(pte_t pte)
return(pte);
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
if (unlikely(pte_get_bits(pte, _PAGE_RW)))
return pte;
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bd9a1804cf72..982b777eadc7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1815,6 +1815,11 @@ config CC_HAS_IBT
(CC_IS_CLANG && CLANG_VERSION >= 140000)) && \
$(as-instr,endbr64)
+config X86_CET
+ def_bool n
+ help
+ CET features configured (Shadow stack or IBT)
+
config X86_KERNEL_IBT
prompt "Indirect Branch Tracking"
def_bool y
@@ -1822,6 +1827,7 @@ config X86_KERNEL_IBT
# https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
depends on !LD_IS_LLD || LLD_VERSION >= 140000
select OBJTOOL
+ select X86_CET
help
Build the kernel with support for Indirect Branch Tracking, a
hardware support course-grain forward-edge Control Flow Integrity
@@ -1915,6 +1921,24 @@ config X86_SGX
If unsure, say N.
+config X86_USER_SHADOW_STACK
+ bool "X86 userspace shadow stack"
+ depends on AS_WRUSS
+ depends on X86_64
+ select ARCH_USES_HIGH_VMA_FLAGS
+ select X86_CET
+ help
+ Shadow stack protection is a hardware feature that detects function
+ return address corruption. This helps mitigate ROP attacks.
+ Applications must be enabled to use it, and old userspace does not
+ get protection "for free".
+
+ CPUs supporting shadow stacks were first released in 2020.
+
+ See Documentation/arch/x86/shstk.rst for more information.
+
+ If unsure, say N.
+
config EFI
bool "EFI runtime service support"
depends on ACPI
diff --git a/arch/x86/Kconfig.assembler b/arch/x86/Kconfig.assembler
index b88f784cb02e..8ad41da301e5 100644
--- a/arch/x86/Kconfig.assembler
+++ b/arch/x86/Kconfig.assembler
@@ -24,3 +24,8 @@ config AS_GFNI
def_bool $(as-instr,vgf2p8mulb %xmm0$(comma)%xmm1$(comma)%xmm2)
help
Supported by binutils >= 2.30 and LLVM integrated assembler
+
+config AS_WRUSS
+ def_bool $(as-instr,wrussq %rax$(comma)(%rbx))
+ help
+ Supported by binutils >= 2.31 and LLVM integrated assembler
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 814768249eae..1d6eee30eceb 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -374,6 +374,7 @@
450 common set_mempolicy_home_node sys_set_mempolicy_home_node
451 common cachestat sys_cachestat
452 common fchmodat2 sys_fchmodat2
+453 64 map_shadow_stack sys_map_shadow_stack
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 7b4ecbf78d8b..2061ed1c398f 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -307,6 +307,7 @@
#define X86_FEATURE_MSR_TSX_CTRL (11*32+20) /* "" MSR IA32_TSX_CTRL (Intel) implemented */
#define X86_FEATURE_SMBA (11*32+21) /* "" Slow Memory Bandwidth Allocation */
#define X86_FEATURE_BMEC (11*32+22) /* "" Bandwidth Monitoring Event Configuration */
+#define X86_FEATURE_USER_SHSTK (11*32+23) /* Shadow stack support for user mode applications */
#define X86_FEATURE_SRSO (11*32+24) /* "" AMD BTB untrain RETs */
#define X86_FEATURE_SRSO_ALIAS (11*32+25) /* "" AMD BTB untrain RETs through aliasing */
@@ -383,6 +384,7 @@
#define X86_FEATURE_OSPKE (16*32+ 4) /* OS Protection Keys Enable */
#define X86_FEATURE_WAITPKG (16*32+ 5) /* UMONITOR/UMWAIT/TPAUSE Instructions */
#define X86_FEATURE_AVX512_VBMI2 (16*32+ 6) /* Additional AVX512 Vector Bit Manipulation Instructions */
+#define X86_FEATURE_SHSTK (16*32+ 7) /* "" Shadow stack */
#define X86_FEATURE_GFNI (16*32+ 8) /* Galois Field New Instructions */
#define X86_FEATURE_VAES (16*32+ 9) /* Vector AES */
#define X86_FEATURE_VPCLMULQDQ (16*32+10) /* Carry-Less Multiplication Double Quadword */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index fafe9be7a6f4..702d93fdd10e 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -105,6 +105,18 @@
# define DISABLE_TDX_GUEST (1 << (X86_FEATURE_TDX_GUEST & 31))
#endif
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+#define DISABLE_USER_SHSTK 0
+#else
+#define DISABLE_USER_SHSTK (1 << (X86_FEATURE_USER_SHSTK & 31))
+#endif
+
+#ifdef CONFIG_X86_KERNEL_IBT
+#define DISABLE_IBT 0
+#else
+#define DISABLE_IBT (1 << (X86_FEATURE_IBT & 31))
+#endif
+
/*
* Make sure to add features to the correct mask
*/
@@ -120,7 +132,7 @@
#define DISABLED_MASK9 (DISABLE_SGX)
#define DISABLED_MASK10 0
#define DISABLED_MASK11 (DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
- DISABLE_CALL_DEPTH_TRACKING)
+ DISABLE_CALL_DEPTH_TRACKING|DISABLE_USER_SHSTK)
#define DISABLED_MASK12 (DISABLE_LAM)
#define DISABLED_MASK13 0
#define DISABLED_MASK14 0
@@ -128,7 +140,7 @@
#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \
DISABLE_ENQCMD)
#define DISABLED_MASK17 0
-#define DISABLED_MASK18 0
+#define DISABLED_MASK18 (DISABLE_IBT)
#define DISABLED_MASK19 0
#define DISABLED_MASK20 0
#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 21)
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index b475d9a582b8..31089b851c4f 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -82,6 +82,15 @@ static inline void fpregs_unlock(void)
preempt_enable();
}
+/*
+ * FPU state gets lazily restored before returning to userspace. So when in the
+ * kernel, the valid FPU state may be kept in the buffer. This function will force
+ * restore all the fpu state to the registers early if needed, and lock them from
+ * being automatically saved/restored. Then FPU state can be modified safely in the
+ * registers, before unlocking with fpregs_unlock().
+ */
+void fpregs_lock_and_load(void);
+
#ifdef CONFIG_X86_DEBUG_FPU
extern void fpregs_assert_state_consistent(void);
#else
diff --git a/arch/x86/include/asm/fpu/regset.h b/arch/x86/include/asm/fpu/regset.h
index 4f928d6a367b..697b77e96025 100644
--- a/arch/x86/include/asm/fpu/regset.h
+++ b/arch/x86/include/asm/fpu/regset.h
@@ -7,11 +7,12 @@
#include <linux/regset.h>
-extern user_regset_active_fn regset_fpregs_active, regset_xregset_fpregs_active;
+extern user_regset_active_fn regset_fpregs_active, regset_xregset_fpregs_active,
+ ssp_active;
extern user_regset_get2_fn fpregs_get, xfpregs_get, fpregs_soft_get,
- xstateregs_get;
+ xstateregs_get, ssp_get;
extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set,
- xstateregs_set;
+ xstateregs_set, ssp_set;
/*
* xstateregs_active == regset_fpregs_active. Please refer to the comment
diff --git a/arch/x86/include/asm/fpu/sched.h b/arch/x86/include/asm/fpu/sched.h
index 78fcde7b1f07..ca6e5e5f16b2 100644
--- a/arch/x86/include/asm/fpu/sched.h
+++ b/arch/x86/include/asm/fpu/sched.h
@@ -11,7 +11,8 @@
extern void save_fpregs_to_fpstate(struct fpu *fpu);
extern void fpu__drop(struct fpu *fpu);
-extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal);
+extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
+ unsigned long shstk_addr);
extern void fpu_flush_thread(void);
/*
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 7f6d858ff47a..eb810074f1e7 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -115,8 +115,8 @@ enum xfeature {
XFEATURE_PT_UNIMPLEMENTED_SO_FAR,
XFEATURE_PKRU,
XFEATURE_PASID,
- XFEATURE_RSRVD_COMP_11,
- XFEATURE_RSRVD_COMP_12,
+ XFEATURE_CET_USER,
+ XFEATURE_CET_KERNEL_UNUSED,
XFEATURE_RSRVD_COMP_13,
XFEATURE_RSRVD_COMP_14,
XFEATURE_LBR,
@@ -138,6 +138,8 @@ enum xfeature {
#define XFEATURE_MASK_PT (1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR)
#define XFEATURE_MASK_PKRU (1 << XFEATURE_PKRU)
#define XFEATURE_MASK_PASID (1 << XFEATURE_PASID)
+#define XFEATURE_MASK_CET_USER (1 << XFEATURE_CET_USER)
+#define XFEATURE_MASK_CET_KERNEL (1 << XFEATURE_CET_KERNEL_UNUSED)
#define XFEATURE_MASK_LBR (1 << XFEATURE_LBR)
#define XFEATURE_MASK_XTILE_CFG (1 << XFEATURE_XTILE_CFG)
#define XFEATURE_MASK_XTILE_DATA (1 << XFEATURE_XTILE_DATA)
@@ -253,6 +255,16 @@ struct pkru_state {
} __packed;
/*
+ * State component 11 is Control-flow Enforcement user states
+ */
+struct cet_user_state {
+ /* user control-flow settings */
+ u64 user_cet;
+ /* user shadow stack pointer */
+ u64 user_ssp;
+};
+
+/*
* State component 15: Architectural LBR configuration state.
* The size of Arch LBR state depends on the number of LBRs (lbr_depth).
*/
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index cd3dd170e23a..d4427b88ee12 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -50,7 +50,8 @@
#define XFEATURE_MASK_USER_DYNAMIC XFEATURE_MASK_XTILE_DATA
/* All currently supported supervisor features */
-#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
+#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID | \
+ XFEATURE_MASK_CET_USER)
/*
* A supervisor state component may not always contain valuable information,
@@ -77,7 +78,8 @@
* Unsupported supervisor features. When a supervisor feature in this mask is
* supported in the future, move it to the supported supervisor feature mask.
*/
-#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT)
+#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT | \
+ XFEATURE_MASK_CET_KERNEL)
/* All supervisor states including supported and unsupported states. */
#define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index cd5c10a74071..05fd175cec7d 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -614,7 +614,7 @@ DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF, xenpv_exc_double_fault);
#endif
/* #CP */
-#ifdef CONFIG_X86_KERNEL_IBT
+#ifdef CONFIG_X86_CET
DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_CP, exc_control_protection);
#endif
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 1d29dc791f5a..416901d406f8 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -186,6 +186,8 @@ do { \
#else
#define deactivate_mm(tsk, mm) \
do { \
+ if (!tsk->vfork_done) \
+ shstk_free(tsk); \
load_gs_index(0); \
loadsegment(fs, 0); \
} while (0)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index dbf8af70b7c2..d6ad98ca1288 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -125,9 +125,15 @@ extern pmdval_t early_pmd_flags;
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
-static inline int pte_dirty(pte_t pte)
+static inline bool pte_dirty(pte_t pte)
{
- return pte_flags(pte) & _PAGE_DIRTY;
+ return pte_flags(pte) & _PAGE_DIRTY_BITS;
+}
+
+static inline bool pte_shstk(pte_t pte)
+{
+ return cpu_feature_enabled(X86_FEATURE_SHSTK) &&
+ (pte_flags(pte) & (_PAGE_RW | _PAGE_DIRTY)) == _PAGE_DIRTY;
}
static inline int pte_young(pte_t pte)
@@ -135,9 +141,16 @@ static inline int pte_young(pte_t pte)
return pte_flags(pte) & _PAGE_ACCESSED;
}
-static inline int pmd_dirty(pmd_t pmd)
+static inline bool pmd_dirty(pmd_t pmd)
+{
+ return pmd_flags(pmd) & _PAGE_DIRTY_BITS;
+}
+
+static inline bool pmd_shstk(pmd_t pmd)
{
- return pmd_flags(pmd) & _PAGE_DIRTY;
+ return cpu_feature_enabled(X86_FEATURE_SHSTK) &&
+ (pmd_flags(pmd) & (_PAGE_RW | _PAGE_DIRTY | _PAGE_PSE)) ==
+ (_PAGE_DIRTY | _PAGE_PSE);
}
#define pmd_young pmd_young
@@ -146,9 +159,9 @@ static inline int pmd_young(pmd_t pmd)
return pmd_flags(pmd) & _PAGE_ACCESSED;
}
-static inline int pud_dirty(pud_t pud)
+static inline bool pud_dirty(pud_t pud)
{
- return pud_flags(pud) & _PAGE_DIRTY;
+ return pud_flags(pud) & _PAGE_DIRTY_BITS;
}
static inline int pud_young(pud_t pud)
@@ -158,7 +171,27 @@ static inline int pud_young(pud_t pud)
static inline int pte_write(pte_t pte)
{
- return pte_flags(pte) & _PAGE_RW;
+ /*
+ * Shadow stack pages are logically writable, but do not have
+ * _PAGE_RW. Check for them separately from _PAGE_RW itself.
+ */
+ return (pte_flags(pte) & _PAGE_RW) || pte_shstk(pte);
+}
+
+#define pmd_write pmd_write
+static inline int pmd_write(pmd_t pmd)
+{
+ /*
+ * Shadow stack pages are logically writable, but do not have
+ * _PAGE_RW. Check for them separately from _PAGE_RW itself.
+ */
+ return (pmd_flags(pmd) & _PAGE_RW) || pmd_shstk(pmd);
+}
+
+#define pud_write pud_write
+static inline int pud_write(pud_t pud)
+{
+ return pud_flags(pud) & _PAGE_RW;
}
static inline int pte_huge(pte_t pte)
@@ -292,9 +325,63 @@ static inline pte_t pte_clear_flags(pte_t pte, pteval_t clear)
return native_make_pte(v & ~clear);
}
+/*
+ * Write protection operations can result in Dirty=1,Write=0 PTEs. But in the
+ * case of X86_FEATURE_USER_SHSTK, these PTEs denote shadow stack memory. So
+ * when creating dirty, write-protected memory, a software bit is used:
+ * _PAGE_BIT_SAVED_DIRTY. The following functions take a PTE and transition the
+ * Dirty bit to SavedDirty, and vice-vesra.
+ *
+ * This shifting is only done if needed. In the case of shifting
+ * Dirty->SavedDirty, the condition is if the PTE is Write=0. In the case of
+ * shifting SavedDirty->Dirty, the condition is Write=1.
+ */
+static inline pgprotval_t mksaveddirty_shift(pgprotval_t v)
+{
+ pgprotval_t cond = (~v >> _PAGE_BIT_RW) & 1;
+
+ v |= ((v >> _PAGE_BIT_DIRTY) & cond) << _PAGE_BIT_SAVED_DIRTY;
+ v &= ~(cond << _PAGE_BIT_DIRTY);
+
+ return v;
+}
+
+static inline pgprotval_t clear_saveddirty_shift(pgprotval_t v)
+{
+ pgprotval_t cond = (v >> _PAGE_BIT_RW) & 1;
+
+ v |= ((v >> _PAGE_BIT_SAVED_DIRTY) & cond) << _PAGE_BIT_DIRTY;
+ v &= ~(cond << _PAGE_BIT_SAVED_DIRTY);
+
+ return v;
+}
+
+static inline pte_t pte_mksaveddirty(pte_t pte)
+{
+ pteval_t v = native_pte_val(pte);
+
+ v = mksaveddirty_shift(v);
+ return native_make_pte(v);
+}
+
+static inline pte_t pte_clear_saveddirty(pte_t pte)
+{
+ pteval_t v = native_pte_val(pte);
+
+ v = clear_saveddirty_shift(v);
+ return native_make_pte(v);
+}
+
static inline pte_t pte_wrprotect(pte_t pte)
{
- return pte_clear_flags(pte, _PAGE_RW);
+ pte = pte_clear_flags(pte, _PAGE_RW);
+
+ /*
+ * Blindly clearing _PAGE_RW might accidentally create
+ * a shadow stack PTE (Write=0,Dirty=1). Move the hardware
+ * dirty value to the software bit, if present.
+ */
+ return pte_mksaveddirty(pte);
}
#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP
@@ -332,7 +419,7 @@ static inline pte_t pte_clear_uffd_wp(pte_t pte)
static inline pte_t pte_mkclean(pte_t pte)
{
- return pte_clear_flags(pte, _PAGE_DIRTY);
+ return pte_clear_flags(pte, _PAGE_DIRTY_BITS);
}
static inline pte_t pte_mkold(pte_t pte)
@@ -347,7 +434,16 @@ static inline pte_t pte_mkexec(pte_t pte)
static inline pte_t pte_mkdirty(pte_t pte)
{
- return pte_set_flags(pte, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+ pte = pte_set_flags(pte, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+
+ return pte_mksaveddirty(pte);
+}
+
+static inline pte_t pte_mkwrite_shstk(pte_t pte)
+{
+ pte = pte_clear_flags(pte, _PAGE_RW);
+
+ return pte_set_flags(pte, _PAGE_DIRTY);
}
static inline pte_t pte_mkyoung(pte_t pte)
@@ -355,11 +451,15 @@ static inline pte_t pte_mkyoung(pte_t pte)
return pte_set_flags(pte, _PAGE_ACCESSED);
}
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{
return pte_set_flags(pte, _PAGE_RW);
}
+struct vm_area_struct;
+pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma);
+#define pte_mkwrite pte_mkwrite
+
static inline pte_t pte_mkhuge(pte_t pte)
{
return pte_set_flags(pte, _PAGE_PSE);
@@ -404,9 +504,34 @@ static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear)
return native_make_pmd(v & ~clear);
}
+/* See comments above mksaveddirty_shift() */
+static inline pmd_t pmd_mksaveddirty(pmd_t pmd)
+{
+ pmdval_t v = native_pmd_val(pmd);
+
+ v = mksaveddirty_shift(v);
+ return native_make_pmd(v);
+}
+
+/* See comments above mksaveddirty_shift() */
+static inline pmd_t pmd_clear_saveddirty(pmd_t pmd)
+{
+ pmdval_t v = native_pmd_val(pmd);
+
+ v = clear_saveddirty_shift(v);
+ return native_make_pmd(v);
+}
+
static inline pmd_t pmd_wrprotect(pmd_t pmd)
{
- return pmd_clear_flags(pmd, _PAGE_RW);
+ pmd = pmd_clear_flags(pmd, _PAGE_RW);
+
+ /*
+ * Blindly clearing _PAGE_RW might accidentally create
+ * a shadow stack PMD (RW=0, Dirty=1). Move the hardware
+ * dirty value to the software bit.
+ */
+ return pmd_mksaveddirty(pmd);
}
#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP
@@ -433,12 +558,21 @@ static inline pmd_t pmd_mkold(pmd_t pmd)
static inline pmd_t pmd_mkclean(pmd_t pmd)
{
- return pmd_clear_flags(pmd, _PAGE_DIRTY);
+ return pmd_clear_flags(pmd, _PAGE_DIRTY_BITS);
}
static inline pmd_t pmd_mkdirty(pmd_t pmd)
{
- return pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+ pmd = pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+
+ return pmd_mksaveddirty(pmd);
+}
+
+static inline pmd_t pmd_mkwrite_shstk(pmd_t pmd)
+{
+ pmd = pmd_clear_flags(pmd, _PAGE_RW);
+
+ return pmd_set_flags(pmd, _PAGE_DIRTY);
}
static inline pmd_t pmd_mkdevmap(pmd_t pmd)
@@ -456,11 +590,14 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
return pmd_set_flags(pmd, _PAGE_ACCESSED);
}
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
{
return pmd_set_flags(pmd, _PAGE_RW);
}
+pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
+#define pmd_mkwrite pmd_mkwrite
+
static inline pud_t pud_set_flags(pud_t pud, pudval_t set)
{
pudval_t v = native_pud_val(pud);
@@ -475,6 +612,24 @@ static inline pud_t pud_clear_flags(pud_t pud, pudval_t clear)
return native_make_pud(v & ~clear);
}
+/* See comments above mksaveddirty_shift() */
+static inline pud_t pud_mksaveddirty(pud_t pud)
+{
+ pudval_t v = native_pud_val(pud);
+
+ v = mksaveddirty_shift(v);
+ return native_make_pud(v);
+}
+
+/* See comments above mksaveddirty_shift() */
+static inline pud_t pud_clear_saveddirty(pud_t pud)
+{
+ pudval_t v = native_pud_val(pud);
+
+ v = clear_saveddirty_shift(v);
+ return native_make_pud(v);
+}
+
static inline pud_t pud_mkold(pud_t pud)
{
return pud_clear_flags(pud, _PAGE_ACCESSED);
@@ -482,17 +637,26 @@ static inline pud_t pud_mkold(pud_t pud)
static inline pud_t pud_mkclean(pud_t pud)
{
- return pud_clear_flags(pud, _PAGE_DIRTY);
+ return pud_clear_flags(pud, _PAGE_DIRTY_BITS);
}
static inline pud_t pud_wrprotect(pud_t pud)
{
- return pud_clear_flags(pud, _PAGE_RW);
+ pud = pud_clear_flags(pud, _PAGE_RW);
+
+ /*
+ * Blindly clearing _PAGE_RW might accidentally create
+ * a shadow stack PUD (RW=0, Dirty=1). Move the hardware
+ * dirty value to the software bit.
+ */
+ return pud_mksaveddirty(pud);
}
static inline pud_t pud_mkdirty(pud_t pud)
{
- return pud_set_flags(pud, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+ pud = pud_set_flags(pud, _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
+
+ return pud_mksaveddirty(pud);
}
static inline pud_t pud_mkdevmap(pud_t pud)
@@ -512,7 +676,9 @@ static inline pud_t pud_mkyoung(pud_t pud)
static inline pud_t pud_mkwrite(pud_t pud)
{
- return pud_set_flags(pud, _PAGE_RW);
+ pud = pud_set_flags(pud, _PAGE_RW);
+
+ return pud_clear_saveddirty(pud);
}
#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
@@ -629,6 +795,7 @@ static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask);
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
pteval_t val = pte_val(pte), oldval = val;
+ pte_t pte_result;
/*
* Chop off the NX bit (if present), and add the NX portion of
@@ -637,17 +804,54 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
val &= _PAGE_CHG_MASK;
val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK;
val = flip_protnone_guard(oldval, val, PTE_PFN_MASK);
- return __pte(val);
+
+ pte_result = __pte(val);
+
+ /*
+ * To avoid creating Write=0,Dirty=1 PTEs, pte_modify() needs to avoid:
+ * 1. Marking Write=0 PTEs Dirty=1
+ * 2. Marking Dirty=1 PTEs Write=0
+ *
+ * The first case cannot happen because the _PAGE_CHG_MASK will filter
+ * out any Dirty bit passed in newprot. Handle the second case by
+ * going through the mksaveddirty exercise. Only do this if the old
+ * value was Write=1 to avoid doing this on Shadow Stack PTEs.
+ */
+ if (oldval & _PAGE_RW)
+ pte_result = pte_mksaveddirty(pte_result);
+ else
+ pte_result = pte_clear_saveddirty(pte_result);
+
+ return pte_result;
}
static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
{
pmdval_t val = pmd_val(pmd), oldval = val;
+ pmd_t pmd_result;
- val &= _HPAGE_CHG_MASK;
+ val &= (_HPAGE_CHG_MASK & ~_PAGE_DIRTY);
val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK;
val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK);
- return __pmd(val);
+
+ pmd_result = __pmd(val);
+
+ /*
+ * To avoid creating Write=0,Dirty=1 PMDs, pte_modify() needs to avoid:
+ * 1. Marking Write=0 PMDs Dirty=1
+ * 2. Marking Dirty=1 PMDs Write=0
+ *
+ * The first case cannot happen because the _PAGE_CHG_MASK will filter
+ * out any Dirty bit passed in newprot. Handle the second case by
+ * going through the mksaveddirty exercise. Only do this if the old
+ * value was Write=1 to avoid doing this on Shadow Stack PTEs.
+ */
+ if (oldval & _PAGE_RW)
+ pmd_result = pmd_mksaveddirty(pmd_result);
+ else
+ pmd_result = pmd_clear_saveddirty(pmd_result);
+
+ return pmd_result;
}
/*
@@ -831,7 +1035,14 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
* (Currently stuck as a macro because of indirect forward reference
* to linux/mm.h:page_to_nid())
*/
-#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
+#define mk_pte(page, pgprot) \
+({ \
+ pgprot_t __pgprot = pgprot; \
+ \
+ WARN_ON_ONCE((pgprot_val(__pgprot) & (_PAGE_DIRTY | _PAGE_RW)) == \
+ _PAGE_DIRTY); \
+ pfn_pte(page_to_pfn(page), __pgprot); \
+})
static inline int pmd_bad(pmd_t pmd)
{
@@ -1090,7 +1301,17 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
static inline void ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
- clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte);
+ /*
+ * Avoid accidentally creating shadow stack PTEs
+ * (Write=0,Dirty=1). Use cmpxchg() to prevent races with
+ * the hardware setting Dirty=1.
+ */
+ pte_t old_pte, new_pte;
+
+ old_pte = READ_ONCE(*ptep);
+ do {
+ new_pte = pte_wrprotect(old_pte);
+ } while (!try_cmpxchg((long *)&ptep->pte, (long *)&old_pte, *(long *)&new_pte));
}
#define flush_tlb_fix_spurious_fault(vma, address, ptep) do { } while (0)
@@ -1116,12 +1337,6 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp);
-#define pmd_write pmd_write
-static inline int pmd_write(pmd_t pmd)
-{
- return pmd_flags(pmd) & _PAGE_RW;
-}
-
#define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp)
@@ -1148,13 +1363,17 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pmd_t *pmdp)
{
- clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp);
-}
+ /*
+ * Avoid accidentally creating shadow stack PTEs
+ * (Write=0,Dirty=1). Use cmpxchg() to prevent races with
+ * the hardware setting Dirty=1.
+ */
+ pmd_t old_pmd, new_pmd;
-#define pud_write pud_write
-static inline int pud_write(pud_t pud)
-{
- return pud_flags(pud) & _PAGE_RW;
+ old_pmd = READ_ONCE(*pmdp);
+ do {
+ new_pmd = pmd_wrprotect(old_pmd);
+ } while (!try_cmpxchg((long *)pmdp, (long *)&old_pmd, *(long *)&new_pmd));
}
#ifndef pmdp_establish
@@ -1412,6 +1631,11 @@ static inline bool __pte_access_permitted(unsigned long pteval, bool write)
{
unsigned long need_pte_bits = _PAGE_PRESENT|_PAGE_USER;
+ /*
+ * Write=0,Dirty=1 PTEs are shadow stack, which the kernel
+ * shouldn't generally allow access to, but since they
+ * are already Write=0, the below logic covers both cases.
+ */
if (write)
need_pte_bits |= _PAGE_RW;
@@ -1453,6 +1677,12 @@ static inline bool arch_has_hw_pte_young(void)
return true;
}
+#define arch_check_zapped_pte arch_check_zapped_pte
+void arch_check_zapped_pte(struct vm_area_struct *vma, pte_t pte);
+
+#define arch_check_zapped_pmd arch_check_zapped_pmd
+void arch_check_zapped_pmd(struct vm_area_struct *vma, pmd_t pmd);
+
#ifdef CONFIG_XEN_PV
#define arch_has_hw_nonleaf_pmd_young arch_has_hw_nonleaf_pmd_young
static inline bool arch_has_hw_nonleaf_pmd_young(void)
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index a6deb67cfbb2..0b748ee16b3d 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -21,7 +21,8 @@
#define _PAGE_BIT_SOFTW2 10 /* " */
#define _PAGE_BIT_SOFTW3 11 /* " */
#define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */
-#define _PAGE_BIT_SOFTW4 58 /* available for programmer */
+#define _PAGE_BIT_SOFTW4 57 /* available for programmer */
+#define _PAGE_BIT_SOFTW5 58 /* available for programmer */
#define _PAGE_BIT_PKEY_BIT0 59 /* Protection Keys, bit 1/4 */
#define _PAGE_BIT_PKEY_BIT1 60 /* Protection Keys, bit 2/4 */
#define _PAGE_BIT_PKEY_BIT2 61 /* Protection Keys, bit 3/4 */
@@ -34,6 +35,13 @@
#define _PAGE_BIT_SOFT_DIRTY _PAGE_BIT_SOFTW3 /* software dirty tracking */
#define _PAGE_BIT_DEVMAP _PAGE_BIT_SOFTW4
+#ifdef CONFIG_X86_64
+#define _PAGE_BIT_SAVED_DIRTY _PAGE_BIT_SOFTW5 /* Saved Dirty bit */
+#else
+/* Shared with _PAGE_BIT_UFFD_WP which is not supported on 32 bit */
+#define _PAGE_BIT_SAVED_DIRTY _PAGE_BIT_SOFTW2 /* Saved Dirty bit */
+#endif
+
/* If _PAGE_BIT_PRESENT is clear, we use these: */
/* - if the user mapped it with PROT_NONE; pte_present gives true */
#define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL
@@ -117,6 +125,18 @@
#define _PAGE_SOFTW4 (_AT(pteval_t, 0))
#endif
+/*
+ * The hardware requires shadow stack to be Write=0,Dirty=1. However,
+ * there are valid cases where the kernel might create read-only PTEs that
+ * are dirty (e.g., fork(), mprotect(), uffd-wp(), soft-dirty tracking). In
+ * this case, the _PAGE_SAVED_DIRTY bit is used instead of the HW-dirty bit,
+ * to avoid creating a wrong "shadow stack" PTEs. Such PTEs have
+ * (Write=0,SavedDirty=1,Dirty=0) set.
+ */
+#define _PAGE_SAVED_DIRTY (_AT(pteval_t, 1) << _PAGE_BIT_SAVED_DIRTY)
+
+#define _PAGE_DIRTY_BITS (_PAGE_DIRTY | _PAGE_SAVED_DIRTY)
+
#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
/*
@@ -125,10 +145,10 @@
* instance, and is *not* included in this mask since
* pte_modify() does modify it.
*/
-#define _COMMON_PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
- _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY |\
- _PAGE_SOFT_DIRTY | _PAGE_DEVMAP | _PAGE_ENC | \
- _PAGE_UFFD_WP)
+#define _COMMON_PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
+ _PAGE_SPECIAL | _PAGE_ACCESSED | \
+ _PAGE_DIRTY_BITS | _PAGE_SOFT_DIRTY | \
+ _PAGE_DEVMAP | _PAGE_ENC | _PAGE_UFFD_WP)
#define _PAGE_CHG_MASK (_COMMON_PAGE_CHG_MASK | _PAGE_PAT)
#define _HPAGE_CHG_MASK (_COMMON_PAGE_CHG_MASK | _PAGE_PSE | _PAGE_PAT_LARGE)
@@ -189,14 +209,22 @@ enum page_cache_mode {
#define __PAGE_KERNEL (__PP|__RW| 0|___A|__NX|___D| 0|___G)
#define __PAGE_KERNEL_EXEC (__PP|__RW| 0|___A| 0|___D| 0|___G)
+
+/*
+ * Page tables needs to have Write=1 in order for any lower PTEs to be
+ * writable. This includes shadow stack memory (Write=0, Dirty=1)
+ */
#define _KERNPG_TABLE_NOENC (__PP|__RW| 0|___A| 0|___D| 0| 0)
#define _KERNPG_TABLE (__PP|__RW| 0|___A| 0|___D| 0| 0| _ENC)
#define _PAGE_TABLE_NOENC (__PP|__RW|_USR|___A| 0|___D| 0| 0)
#define _PAGE_TABLE (__PP|__RW|_USR|___A| 0|___D| 0| 0| _ENC)
-#define __PAGE_KERNEL_RO (__PP| 0| 0|___A|__NX|___D| 0|___G)
-#define __PAGE_KERNEL_ROX (__PP| 0| 0|___A| 0|___D| 0|___G)
+
+#define __PAGE_KERNEL_RO (__PP| 0| 0|___A|__NX| 0| 0|___G)
+#define __PAGE_KERNEL_ROX (__PP| 0| 0|___A| 0| 0| 0|___G)
+#define __PAGE_KERNEL (__PP|__RW| 0|___A|__NX|___D| 0|___G)
+#define __PAGE_KERNEL_EXEC (__PP|__RW| 0|___A| 0|___D| 0|___G)
#define __PAGE_KERNEL_NOCACHE (__PP|__RW| 0|___A|__NX|___D| 0|___G| __NC)
-#define __PAGE_KERNEL_VVAR (__PP| 0|_USR|___A|__NX|___D| 0|___G)
+#define __PAGE_KERNEL_VVAR (__PP| 0|_USR|___A|__NX| 0| 0|___G)
#define __PAGE_KERNEL_LARGE (__PP|__RW| 0|___A|__NX|___D|_PSE|___G)
#define __PAGE_KERNEL_LARGE_EXEC (__PP|__RW| 0|___A| 0|___D|_PSE|___G)
#define __PAGE_KERNEL_WP (__PP|__RW| 0|___A|__NX|___D| 0|___G| __WP)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index cbb943010c1e..0086920cda06 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -28,6 +28,7 @@ struct vm86;
#include <asm/unwind_hints.h>
#include <asm/vmxfeatures.h>
#include <asm/vdso/processor.h>
+#include <asm/shstk.h>
#include <linux/personality.h>
#include <linux/cache.h>
@@ -474,6 +475,13 @@ struct thread_struct {
*/
u32 pkru;
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+ unsigned long features;
+ unsigned long features_locked;
+
+ struct thread_shstk shstk;
+#endif
+
/* Floating point and extended processor state */
struct fpu fpu;
/*
diff --git a/arch/x86/include/asm/shstk.h b/arch/x86/include/asm/shstk.h
new file mode 100644
index 000000000000..42fee8959df7
--- /dev/null
+++ b/arch/x86/include/asm/shstk.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_SHSTK_H
+#define _ASM_X86_SHSTK_H
+
+#ifndef __ASSEMBLY__
+#include <linux/types.h>
+
+struct task_struct;
+struct ksignal;
+
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+struct thread_shstk {
+ u64 base;
+ u64 size;
+};
+
+long shstk_prctl(struct task_struct *task, int option, unsigned long arg2);
+void reset_thread_features(void);
+unsigned long shstk_alloc_thread_stack(struct task_struct *p, unsigned long clone_flags,
+ unsigned long stack_size);
+void shstk_free(struct task_struct *p);
+int setup_signal_shadow_stack(struct ksignal *ksig);
+int restore_signal_shadow_stack(void);
+#else
+static inline long shstk_prctl(struct task_struct *task, int option,
+ unsigned long arg2) { return -EINVAL; }
+static inline void reset_thread_features(void) {}
+static inline unsigned long shstk_alloc_thread_stack(struct task_struct *p,
+ unsigned long clone_flags,
+ unsigned long stack_size) { return 0; }
+static inline void shstk_free(struct task_struct *p) {}
+static inline int setup_signal_shadow_stack(struct ksignal *ksig) { return 0; }
+static inline int restore_signal_shadow_stack(void) { return 0; }
+#endif /* CONFIG_X86_USER_SHADOW_STACK */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_X86_SHSTK_H */
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index de48d1389936..d6cd9344f6c7 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -202,6 +202,19 @@ static inline void clwb(volatile void *__p)
: [pax] "a" (p));
}
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+static inline int write_user_shstk_64(u64 __user *addr, u64 val)
+{
+ asm_volatile_goto("1: wrussq %[val], (%[addr])\n"
+ _ASM_EXTABLE(1b, %l[fail])
+ :: [addr] "r" (addr), [val] "r" (val)
+ :: fail);
+ return 0;
+fail:
+ return -EFAULT;
+}
+#endif /* CONFIG_X86_USER_SHADOW_STACK */
+
#define nop() asm volatile ("nop")
static inline void serialize(void)
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 6ab42caaa67a..25726893c6f4 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -306,7 +306,8 @@ static inline bool pte_flags_need_flush(unsigned long oldflags,
const pteval_t flush_on_clear = _PAGE_DIRTY | _PAGE_PRESENT |
_PAGE_ACCESSED;
const pteval_t software_flags = _PAGE_SOFTW1 | _PAGE_SOFTW2 |
- _PAGE_SOFTW3 | _PAGE_SOFTW4;
+ _PAGE_SOFTW3 | _PAGE_SOFTW4 |
+ _PAGE_SAVED_DIRTY;
const pteval_t flush_on_change = _PAGE_RW | _PAGE_USER | _PAGE_PWT |
_PAGE_PCD | _PAGE_PSE | _PAGE_GLOBAL | _PAGE_PAT |
_PAGE_PAT_LARGE | _PAGE_PKEY_BIT0 | _PAGE_PKEY_BIT1 |
diff --git a/arch/x86/include/asm/trap_pf.h b/arch/x86/include/asm/trap_pf.h
index 10b1de500ab1..afa524325e55 100644
--- a/arch/x86/include/asm/trap_pf.h
+++ b/arch/x86/include/asm/trap_pf.h
@@ -11,6 +11,7 @@
* bit 3 == 1: use of reserved bit detected
* bit 4 == 1: fault was an instruction fetch
* bit 5 == 1: protection keys block access
+ * bit 6 == 1: shadow stack access fault
* bit 15 == 1: SGX MMU page-fault
*/
enum x86_pf_error_code {
@@ -20,6 +21,7 @@ enum x86_pf_error_code {
X86_PF_RSVD = 1 << 3,
X86_PF_INSTR = 1 << 4,
X86_PF_PK = 1 << 5,
+ X86_PF_SHSTK = 1 << 6,
X86_PF_SGX = 1 << 15,
};
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 47ecfff2c83d..b1c9cea6ba88 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -18,7 +18,8 @@ void __init trap_init(void);
asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs);
#endif
-extern bool ibt_selftest(void);
+extern int ibt_selftest(void);
+extern int ibt_selftest_noendbr(void);
#ifdef CONFIG_X86_F00F_BUG
/* For handling the FOOF bug */
@@ -47,4 +48,16 @@ void __noreturn handle_stack_overflow(struct pt_regs *regs,
struct stack_info *info);
#endif
+static inline void cond_local_irq_enable(struct pt_regs *regs)
+{
+ if (regs->flags & X86_EFLAGS_IF)
+ local_irq_enable();
+}
+
+static inline void cond_local_irq_disable(struct pt_regs *regs)
+{
+ if (regs->flags & X86_EFLAGS_IF)
+ local_irq_disable();
+}
+
#endif /* _ASM_X86_TRAPS_H */
diff --git a/arch/x86/include/uapi/asm/mman.h b/arch/x86/include/uapi/asm/mman.h
index 775dbd3aff73..8148bdddbd2c 100644
--- a/arch/x86/include/uapi/asm/mman.h
+++ b/arch/x86/include/uapi/asm/mman.h
@@ -3,6 +3,7 @@
#define _ASM_X86_MMAN_H
#define MAP_32BIT 0x40 /* only give out 32bit addresses */
+#define MAP_ABOVE4G 0x80 /* only map above 4GB */
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
#define arch_calc_vm_prot_bits(prot, key) ( \
@@ -12,6 +13,9 @@
((key) & 0x8 ? VM_PKEY_BIT3 : 0))
#endif
+/* Flags for map_shadow_stack(2) */
+#define SHADOW_STACK_SET_TOKEN (1ULL << 0) /* Set up a restore token in the shadow stack */
+
#include <asm-generic/mman.h>
#endif /* _ASM_X86_MMAN_H */
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index e8d7ebbca1a4..384e2cc6ac19 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -23,9 +23,21 @@
#define ARCH_MAP_VDSO_32 0x2002
#define ARCH_MAP_VDSO_64 0x2003
+/* Don't use 0x3001-0x3004 because of old glibcs */
+
#define ARCH_GET_UNTAG_MASK 0x4001
#define ARCH_ENABLE_TAGGED_ADDR 0x4002
#define ARCH_GET_MAX_TAG_BITS 0x4003
#define ARCH_FORCE_TAGGED_SVA 0x4004
+#define ARCH_SHSTK_ENABLE 0x5001
+#define ARCH_SHSTK_DISABLE 0x5002
+#define ARCH_SHSTK_LOCK 0x5003
+#define ARCH_SHSTK_UNLOCK 0x5004
+#define ARCH_SHSTK_STATUS 0x5005
+
+/* ARCH_SHSTK_ features bits */
+#define ARCH_SHSTK_SHSTK (1ULL << 0)
+#define ARCH_SHSTK_WRSS (1ULL << 1)
+
#endif /* _ASM_X86_PRCTL_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 00df34c263cc..3269a0e23d3a 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -48,6 +48,7 @@ obj-y += process_$(BITS).o signal.o signal_$(BITS).o
obj-y += traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
obj-y += time.o ioport.o dumpstack.o nmi.o
obj-$(CONFIG_MODIFY_LDT_SYSCALL) += ldt.o
+obj-$(CONFIG_X86_KERNEL_IBT) += ibt_selftest.o
obj-y += setup.o x86_init.o i8259.o irqinit.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_IRQ_WORK) += irq_work.o
@@ -144,6 +145,10 @@ obj-$(CONFIG_CFI_CLANG) += cfi.o
obj-$(CONFIG_CALL_THUNKS) += callthunks.o
+obj-$(CONFIG_X86_CET) += cet.o
+
+obj-$(CONFIG_X86_USER_SHADOW_STACK) += shstk.o
+
###
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c
new file mode 100644
index 000000000000..d2c732a34e5d
--- /dev/null
+++ b/arch/x86/kernel/cet.c
@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ptrace.h>
+#include <asm/bugs.h>
+#include <asm/traps.h>
+
+enum cp_error_code {
+ CP_EC = (1 << 15) - 1,
+
+ CP_RET = 1,
+ CP_IRET = 2,
+ CP_ENDBR = 3,
+ CP_RSTRORSSP = 4,
+ CP_SETSSBSY = 5,
+
+ CP_ENCL = 1 << 15,
+};
+
+static const char cp_err[][10] = {
+ [0] = "unknown",
+ [1] = "near ret",
+ [2] = "far/iret",
+ [3] = "endbranch",
+ [4] = "rstorssp",
+ [5] = "setssbsy",
+};
+
+static const char *cp_err_string(unsigned long error_code)
+{
+ unsigned int cpec = error_code & CP_EC;
+
+ if (cpec >= ARRAY_SIZE(cp_err))
+ cpec = 0;
+ return cp_err[cpec];
+}
+
+static void do_unexpected_cp(struct pt_regs *regs, unsigned long error_code)
+{
+ WARN_ONCE(1, "Unexpected %s #CP, error_code: %s\n",
+ user_mode(regs) ? "user mode" : "kernel mode",
+ cp_err_string(error_code));
+}
+
+static DEFINE_RATELIMIT_STATE(cpf_rate, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+static void do_user_cp_fault(struct pt_regs *regs, unsigned long error_code)
+{
+ struct task_struct *tsk;
+ unsigned long ssp;
+
+ /*
+ * An exception was just taken from userspace. Since interrupts are disabled
+ * here, no scheduling should have messed with the registers yet and they
+ * will be whatever is live in userspace. So read the SSP before enabling
+ * interrupts so locking the fpregs to do it later is not required.
+ */
+ rdmsrl(MSR_IA32_PL3_SSP, ssp);
+
+ cond_local_irq_enable(regs);
+
+ tsk = current;
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_nr = X86_TRAP_CP;
+
+ /* Ratelimit to prevent log spamming. */
+ if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+ __ratelimit(&cpf_rate)) {
+ pr_emerg("%s[%d] control protection ip:%lx sp:%lx ssp:%lx error:%lx(%s)%s",
+ tsk->comm, task_pid_nr(tsk),
+ regs->ip, regs->sp, ssp, error_code,
+ cp_err_string(error_code),
+ error_code & CP_ENCL ? " in enclave" : "");
+ print_vma_addr(KERN_CONT " in ", regs->ip);
+ pr_cont("\n");
+ }
+
+ force_sig_fault(SIGSEGV, SEGV_CPERR, (void __user *)0);
+ cond_local_irq_disable(regs);
+}
+
+static __ro_after_init bool ibt_fatal = true;
+
+static void do_kernel_cp_fault(struct pt_regs *regs, unsigned long error_code)
+{
+ if ((error_code & CP_EC) != CP_ENDBR) {
+ do_unexpected_cp(regs, error_code);
+ return;
+ }
+
+ if (unlikely(regs->ip == (unsigned long)&ibt_selftest_noendbr)) {
+ regs->ax = 0;
+ return;
+ }
+
+ pr_err("Missing ENDBR: %pS\n", (void *)instruction_pointer(regs));
+ if (!ibt_fatal) {
+ printk(KERN_DEFAULT CUT_HERE);
+ __warn(__FILE__, __LINE__, (void *)regs->ip, TAINT_WARN, regs, NULL);
+ return;
+ }
+ BUG();
+}
+
+static int __init ibt_setup(char *str)
+{
+ if (!strcmp(str, "off"))
+ setup_clear_cpu_cap(X86_FEATURE_IBT);
+
+ if (!strcmp(str, "warn"))
+ ibt_fatal = false;
+
+ return 1;
+}
+
+__setup("ibt=", ibt_setup);
+
+DEFINE_IDTENTRY_ERRORCODE(exc_control_protection)
+{
+ if (user_mode(regs)) {
+ if (cpu_feature_enabled(X86_FEATURE_USER_SHSTK))
+ do_user_cp_fault(regs, error_code);
+ else
+ do_unexpected_cp(regs, error_code);
+ } else {
+ if (cpu_feature_enabled(X86_FEATURE_IBT))
+ do_kernel_cp_fault(regs, error_code);
+ else
+ do_unexpected_cp(regs, error_code);
+ }
+}
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 90b8c5ea25aa..6d75fab10161 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -587,27 +587,43 @@ __noendbr void ibt_restore(u64 save)
static __always_inline void setup_cet(struct cpuinfo_x86 *c)
{
- u64 msr = CET_ENDBR_EN;
+ bool user_shstk, kernel_ibt;
- if (!HAS_KERNEL_IBT ||
- !cpu_feature_enabled(X86_FEATURE_IBT))
+ if (!IS_ENABLED(CONFIG_X86_CET))
return;
- wrmsrl(MSR_IA32_S_CET, msr);
+ kernel_ibt = HAS_KERNEL_IBT && cpu_feature_enabled(X86_FEATURE_IBT);
+ user_shstk = cpu_feature_enabled(X86_FEATURE_SHSTK) &&
+ IS_ENABLED(CONFIG_X86_USER_SHADOW_STACK);
+
+ if (!kernel_ibt && !user_shstk)
+ return;
+
+ if (user_shstk)
+ set_cpu_cap(c, X86_FEATURE_USER_SHSTK);
+
+ if (kernel_ibt)
+ wrmsrl(MSR_IA32_S_CET, CET_ENDBR_EN);
+ else
+ wrmsrl(MSR_IA32_S_CET, 0);
+
cr4_set_bits(X86_CR4_CET);
- if (!ibt_selftest()) {
+ if (kernel_ibt && ibt_selftest()) {
pr_err("IBT selftest: Failed!\n");
wrmsrl(MSR_IA32_S_CET, 0);
setup_clear_cpu_cap(X86_FEATURE_IBT);
- return;
}
}
__noendbr void cet_disable(void)
{
- if (cpu_feature_enabled(X86_FEATURE_IBT))
- wrmsrl(MSR_IA32_S_CET, 0);
+ if (!(cpu_feature_enabled(X86_FEATURE_IBT) ||
+ cpu_feature_enabled(X86_FEATURE_SHSTK)))
+ return;
+
+ wrmsrl(MSR_IA32_S_CET, 0);
+ wrmsrl(MSR_IA32_U_CET, 0);
}
/*
@@ -1491,6 +1507,9 @@ static void __init cpu_parse_early_param(void)
if (cmdline_find_option_bool(boot_command_line, "noxsaves"))
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
+ if (cmdline_find_option_bool(boot_command_line, "nousershstk"))
+ setup_clear_cpu_cap(X86_FEATURE_USER_SHSTK);
+
arglen = cmdline_find_option(boot_command_line, "clearcpuid", arg, sizeof(arg));
if (arglen <= 0)
return;
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index f6748c8bd647..e462c1d3800a 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -81,6 +81,7 @@ static const struct cpuid_dep cpuid_deps[] = {
{ X86_FEATURE_XFD, X86_FEATURE_XSAVES },
{ X86_FEATURE_XFD, X86_FEATURE_XGETBV1 },
{ X86_FEATURE_AMX_TILE, X86_FEATURE_XFD },
+ { X86_FEATURE_SHSTK, X86_FEATURE_XSAVES },
{}
};
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 099b6f0d96bd..31c0e68f6227 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -4,6 +4,8 @@
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/cpufreq.h>
+#include <asm/prctl.h>
+#include <linux/proc_fs.h>
#include "cpu.h"
@@ -175,3 +177,24 @@ const struct seq_operations cpuinfo_op = {
.stop = c_stop,
.show = show_cpuinfo,
};
+
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+static void dump_x86_features(struct seq_file *m, unsigned long features)
+{
+ if (features & ARCH_SHSTK_SHSTK)
+ seq_puts(m, "shstk ");
+ if (features & ARCH_SHSTK_WRSS)
+ seq_puts(m, "wrss ");
+}
+
+void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct *task)
+{
+ seq_puts(m, "x86_Thread_features:\t");
+ dump_x86_features(m, task->thread.features);
+ seq_putc(m, '\n');
+
+ seq_puts(m, "x86_Thread_features_locked:\t");
+ dump_x86_features(m, task->thread.features_locked);
+ seq_putc(m, '\n');
+}
+#endif /* CONFIG_X86_USER_SHADOW_STACK */
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 98e507cc7d34..a86d37052a64 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -552,8 +552,36 @@ static inline void fpu_inherit_perms(struct fpu *dst_fpu)
}
}
+/* A passed ssp of zero will not cause any update */
+static int update_fpu_shstk(struct task_struct *dst, unsigned long ssp)
+{
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+ struct cet_user_state *xstate;
+
+ /* If ssp update is not needed. */
+ if (!ssp)
+ return 0;
+
+ xstate = get_xsave_addr(&dst->thread.fpu.fpstate->regs.xsave,
+ XFEATURE_CET_USER);
+
+ /*
+ * If there is a non-zero ssp, then 'dst' must be configured with a shadow
+ * stack and the fpu state should be up to date since it was just copied
+ * from the parent in fpu_clone(). So there must be a valid non-init CET
+ * state location in the buffer.
+ */
+ if (WARN_ON_ONCE(!xstate))
+ return 1;
+
+ xstate->user_ssp = (u64)ssp;
+#endif
+ return 0;
+}
+
/* Clone current's FPU state on fork */
-int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal)
+int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
+ unsigned long ssp)
{
struct fpu *src_fpu = &current->thread.fpu;
struct fpu *dst_fpu = &dst->thread.fpu;
@@ -613,6 +641,12 @@ int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal)
if (use_xsave())
dst_fpu->fpstate->regs.xsave.header.xfeatures &= ~XFEATURE_MASK_PASID;
+ /*
+ * Update shadow stack pointer, in case it changed during clone.
+ */
+ if (update_fpu_shstk(dst, ssp))
+ return 1;
+
trace_x86_fpu_copy_src(src_fpu);
trace_x86_fpu_copy_dst(dst_fpu);
@@ -753,6 +787,24 @@ void switch_fpu_return(void)
}
EXPORT_SYMBOL_GPL(switch_fpu_return);
+void fpregs_lock_and_load(void)
+{
+ /*
+ * fpregs_lock() only disables preemption (mostly). So modifying state
+ * in an interrupt could screw up some in progress fpregs operation.
+ * Warn about it.
+ */
+ WARN_ON_ONCE(!irq_fpu_usable());
+ WARN_ON_ONCE(current->flags & PF_KTHREAD);
+
+ fpregs_lock();
+
+ fpregs_assert_state_consistent();
+
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ fpregs_restore_userregs();
+}
+
#ifdef CONFIG_X86_DEBUG_FPU
/*
* If current FPU state according to its tracking (loaded FPU context on this
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 6d056b68f4ed..6bc1eb2a21bd 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -8,6 +8,7 @@
#include <asm/fpu/api.h>
#include <asm/fpu/signal.h>
#include <asm/fpu/regset.h>
+#include <asm/prctl.h>
#include "context.h"
#include "internal.h"
@@ -174,6 +175,86 @@ out:
return ret;
}
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+int ssp_active(struct task_struct *target, const struct user_regset *regset)
+{
+ if (target->thread.features & ARCH_SHSTK_SHSTK)
+ return regset->n;
+
+ return 0;
+}
+
+int ssp_get(struct task_struct *target, const struct user_regset *regset,
+ struct membuf to)
+{
+ struct fpu *fpu = &target->thread.fpu;
+ struct cet_user_state *cetregs;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK))
+ return -ENODEV;
+
+ sync_fpstate(fpu);
+ cetregs = get_xsave_addr(&fpu->fpstate->regs.xsave, XFEATURE_CET_USER);
+ if (WARN_ON(!cetregs)) {
+ /*
+ * This shouldn't ever be NULL because shadow stack was
+ * verified to be enabled above. This means
+ * MSR_IA32_U_CET.CET_SHSTK_EN should be 1 and so
+ * XFEATURE_CET_USER should not be in the init state.
+ */
+ return -ENODEV;
+ }
+
+ return membuf_write(&to, (unsigned long *)&cetregs->user_ssp,
+ sizeof(cetregs->user_ssp));
+}
+
+int ssp_set(struct task_struct *target, const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ struct fpu *fpu = &target->thread.fpu;
+ struct xregs_state *xsave = &fpu->fpstate->regs.xsave;
+ struct cet_user_state *cetregs;
+ unsigned long user_ssp;
+ int r;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) ||
+ !ssp_active(target, regset))
+ return -ENODEV;
+
+ if (pos != 0 || count != sizeof(user_ssp))
+ return -EINVAL;
+
+ r = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &user_ssp, 0, -1);
+ if (r)
+ return r;
+
+ /*
+ * Some kernel instructions (IRET, etc) can cause exceptions in the case
+ * of disallowed CET register values. Just prevent invalid values.
+ */
+ if (user_ssp >= TASK_SIZE_MAX || !IS_ALIGNED(user_ssp, 8))
+ return -EINVAL;
+
+ fpu_force_restore(fpu);
+
+ cetregs = get_xsave_addr(xsave, XFEATURE_CET_USER);
+ if (WARN_ON(!cetregs)) {
+ /*
+ * This shouldn't ever be NULL because shadow stack was
+ * verified to be enabled above. This means
+ * MSR_IA32_U_CET.CET_SHSTK_EN should be 1 and so
+ * XFEATURE_CET_USER should not be in the init state.
+ */
+ return -ENODEV;
+ }
+
+ cetregs->user_ssp = user_ssp;
+ return 0;
+}
+#endif /* CONFIG_X86_USER_SHADOW_STACK */
+
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
/*
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 1afbc4866b10..41dac93b8ea4 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -39,26 +39,26 @@
*/
static const char *xfeature_names[] =
{
- "x87 floating point registers" ,
- "SSE registers" ,
- "AVX registers" ,
- "MPX bounds registers" ,
- "MPX CSR" ,
- "AVX-512 opmask" ,
- "AVX-512 Hi256" ,
- "AVX-512 ZMM_Hi256" ,
- "Processor Trace (unused)" ,
+ "x87 floating point registers",
+ "SSE registers",
+ "AVX registers",
+ "MPX bounds registers",
+ "MPX CSR",
+ "AVX-512 opmask",
+ "AVX-512 Hi256",
+ "AVX-512 ZMM_Hi256",
+ "Processor Trace (unused)",
"Protection Keys User registers",
"PASID state",
- "unknown xstate feature" ,
- "unknown xstate feature" ,
- "unknown xstate feature" ,
- "unknown xstate feature" ,
- "unknown xstate feature" ,
- "unknown xstate feature" ,
- "AMX Tile config" ,
- "AMX Tile data" ,
- "unknown xstate feature" ,
+ "Control-flow User registers",
+ "Control-flow Kernel registers (unused)",
+ "unknown xstate feature",
+ "unknown xstate feature",
+ "unknown xstate feature",
+ "unknown xstate feature",
+ "AMX Tile config",
+ "AMX Tile data",
+ "unknown xstate feature",
};
static unsigned short xsave_cpuid_features[] __initdata = {
@@ -73,6 +73,7 @@ static unsigned short xsave_cpuid_features[] __initdata = {
[XFEATURE_PT_UNIMPLEMENTED_SO_FAR] = X86_FEATURE_INTEL_PT,
[XFEATURE_PKRU] = X86_FEATURE_PKU,
[XFEATURE_PASID] = X86_FEATURE_ENQCMD,
+ [XFEATURE_CET_USER] = X86_FEATURE_SHSTK,
[XFEATURE_XTILE_CFG] = X86_FEATURE_AMX_TILE,
[XFEATURE_XTILE_DATA] = X86_FEATURE_AMX_TILE,
};
@@ -276,6 +277,7 @@ static void __init print_xstate_features(void)
print_xstate_feature(XFEATURE_MASK_Hi16_ZMM);
print_xstate_feature(XFEATURE_MASK_PKRU);
print_xstate_feature(XFEATURE_MASK_PASID);
+ print_xstate_feature(XFEATURE_MASK_CET_USER);
print_xstate_feature(XFEATURE_MASK_XTILE_CFG);
print_xstate_feature(XFEATURE_MASK_XTILE_DATA);
}
@@ -344,6 +346,7 @@ static __init void os_xrstor_booting(struct xregs_state *xstate)
XFEATURE_MASK_BNDREGS | \
XFEATURE_MASK_BNDCSR | \
XFEATURE_MASK_PASID | \
+ XFEATURE_MASK_CET_USER | \
XFEATURE_MASK_XTILE)
/*
@@ -446,14 +449,15 @@ static void __init __xstate_dump_leaves(void)
} \
} while (0)
-#define XCHECK_SZ(sz, nr, nr_macro, __struct) do { \
- if ((nr == nr_macro) && \
- WARN_ONCE(sz != sizeof(__struct), \
- "%s: struct is %zu bytes, cpu state %d bytes\n", \
- __stringify(nr_macro), sizeof(__struct), sz)) { \
+#define XCHECK_SZ(sz, nr, __struct) ({ \
+ if (WARN_ONCE(sz != sizeof(__struct), \
+ "[%s]: struct is %zu bytes, cpu state %d bytes\n", \
+ xfeature_names[nr], sizeof(__struct), sz)) { \
__xstate_dump_leaves(); \
} \
-} while (0)
+ true; \
+})
+
/**
* check_xtile_data_against_struct - Check tile data state size.
@@ -527,36 +531,28 @@ static bool __init check_xstate_against_struct(int nr)
* Ask the CPU for the size of the state.
*/
int sz = xfeature_size(nr);
+
/*
* Match each CPU state with the corresponding software
* structure.
*/
- XCHECK_SZ(sz, nr, XFEATURE_YMM, struct ymmh_struct);
- XCHECK_SZ(sz, nr, XFEATURE_BNDREGS, struct mpx_bndreg_state);
- XCHECK_SZ(sz, nr, XFEATURE_BNDCSR, struct mpx_bndcsr_state);
- XCHECK_SZ(sz, nr, XFEATURE_OPMASK, struct avx_512_opmask_state);
- XCHECK_SZ(sz, nr, XFEATURE_ZMM_Hi256, struct avx_512_zmm_uppers_state);
- XCHECK_SZ(sz, nr, XFEATURE_Hi16_ZMM, struct avx_512_hi16_state);
- XCHECK_SZ(sz, nr, XFEATURE_PKRU, struct pkru_state);
- XCHECK_SZ(sz, nr, XFEATURE_PASID, struct ia32_pasid_state);
- XCHECK_SZ(sz, nr, XFEATURE_XTILE_CFG, struct xtile_cfg);
-
- /* The tile data size varies between implementations. */
- if (nr == XFEATURE_XTILE_DATA)
- check_xtile_data_against_struct(sz);
-
- /*
- * Make *SURE* to add any feature numbers in below if
- * there are "holes" in the xsave state component
- * numbers.
- */
- if ((nr < XFEATURE_YMM) ||
- (nr >= XFEATURE_MAX) ||
- (nr == XFEATURE_PT_UNIMPLEMENTED_SO_FAR) ||
- ((nr >= XFEATURE_RSRVD_COMP_11) && (nr <= XFEATURE_RSRVD_COMP_16))) {
+ switch (nr) {
+ case XFEATURE_YMM: return XCHECK_SZ(sz, nr, struct ymmh_struct);
+ case XFEATURE_BNDREGS: return XCHECK_SZ(sz, nr, struct mpx_bndreg_state);
+ case XFEATURE_BNDCSR: return XCHECK_SZ(sz, nr, struct mpx_bndcsr_state);
+ case XFEATURE_OPMASK: return XCHECK_SZ(sz, nr, struct avx_512_opmask_state);
+ case XFEATURE_ZMM_Hi256: return XCHECK_SZ(sz, nr, struct avx_512_zmm_uppers_state);
+ case XFEATURE_Hi16_ZMM: return XCHECK_SZ(sz, nr, struct avx_512_hi16_state);
+ case XFEATURE_PKRU: return XCHECK_SZ(sz, nr, struct pkru_state);
+ case XFEATURE_PASID: return XCHECK_SZ(sz, nr, struct ia32_pasid_state);
+ case XFEATURE_XTILE_CFG: return XCHECK_SZ(sz, nr, struct xtile_cfg);
+ case XFEATURE_CET_USER: return XCHECK_SZ(sz, nr, struct cet_user_state);
+ case XFEATURE_XTILE_DATA: check_xtile_data_against_struct(sz); return true;
+ default:
XSTATE_WARN_ON(1, "No structure for xstate: %d\n", nr);
return false;
}
+
return true;
}
diff --git a/arch/x86/kernel/ibt_selftest.S b/arch/x86/kernel/ibt_selftest.S
new file mode 100644
index 000000000000..c43c4ed28a9c
--- /dev/null
+++ b/arch/x86/kernel/ibt_selftest.S
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/linkage.h>
+#include <linux/objtool.h>
+#include <asm/nospec-branch.h>
+
+SYM_CODE_START(ibt_selftest_noendbr)
+ ANNOTATE_NOENDBR
+ UNWIND_HINT_FUNC
+ /* #CP handler sets %ax to 0 */
+ RET
+SYM_CODE_END(ibt_selftest_noendbr)
+
+SYM_FUNC_START(ibt_selftest)
+ lea ibt_selftest_noendbr(%rip), %rax
+ ANNOTATE_RETPOLINE_SAFE
+ jmp *%rax
+SYM_FUNC_END(ibt_selftest)
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index f3958262c725..b786d48f5a0f 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -107,7 +107,7 @@ static const __initconst struct idt_data def_idts[] = {
ISTG(X86_TRAP_MC, asm_exc_machine_check, IST_INDEX_MCE),
#endif
-#ifdef CONFIG_X86_KERNEL_IBT
+#ifdef CONFIG_X86_CET
INTG(X86_TRAP_CP, asm_exc_control_protection),
#endif
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 72015dba72ab..9f0909142a0a 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -51,6 +51,7 @@
#include <asm/unwind.h>
#include <asm/tdx.h>
#include <asm/mmu_context.h>
+#include <asm/shstk.h>
#include "process.h"
@@ -122,6 +123,7 @@ void exit_thread(struct task_struct *tsk)
free_vm86(t);
+ shstk_free(tsk);
fpu__drop(fpu);
}
@@ -162,6 +164,7 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
struct inactive_task_frame *frame;
struct fork_frame *fork_frame;
struct pt_regs *childregs;
+ unsigned long new_ssp;
int ret = 0;
childregs = task_pt_regs(p);
@@ -199,7 +202,16 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
frame->flags = X86_EFLAGS_FIXED;
#endif
- fpu_clone(p, clone_flags, args->fn);
+ /*
+ * Allocate a new shadow stack for thread if needed. If shadow stack,
+ * is disabled, new_ssp will remain 0, and fpu_clone() will know not to
+ * update it.
+ */
+ new_ssp = shstk_alloc_thread_stack(p, clone_flags, args->stack_size);
+ if (IS_ERR_VALUE(new_ssp))
+ return PTR_ERR((void *)new_ssp);
+
+ fpu_clone(p, clone_flags, args->fn, new_ssp);
/* Kernel thread ? */
if (unlikely(p->flags & PF_KTHREAD)) {
@@ -245,6 +257,13 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
if (!ret && unlikely(test_tsk_thread_flag(current, TIF_IO_BITMAP)))
io_bitmap_share(p);
+ /*
+ * If copy_thread() if failing, don't leak the shadow stack possibly
+ * allocated in shstk_alloc_thread_stack() above.
+ */
+ if (ret)
+ shstk_free(p);
+
return ret;
}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 3d181c16a2f6..33b268747bb7 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -515,6 +515,8 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip,
load_gs_index(__USER_DS);
}
+ reset_thread_features();
+
loadsegment(fs, 0);
loadsegment(es, _ds);
loadsegment(ds, _ds);
@@ -894,6 +896,12 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
else
return put_user(LAM_U57_BITS, (unsigned long __user *)arg2);
#endif
+ case ARCH_SHSTK_ENABLE:
+ case ARCH_SHSTK_DISABLE:
+ case ARCH_SHSTK_LOCK:
+ case ARCH_SHSTK_UNLOCK:
+ case ARCH_SHSTK_STATUS:
+ return shstk_prctl(task, option, arg2);
default:
ret = -EINVAL;
break;
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index dfaa270a7cc9..095f04bdabdc 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -58,6 +58,7 @@ enum x86_regset_64 {
REGSET64_FP,
REGSET64_IOPERM,
REGSET64_XSTATE,
+ REGSET64_SSP,
};
#define REGSET_GENERAL \
@@ -1267,6 +1268,17 @@ static struct user_regset x86_64_regsets[] __ro_after_init = {
.active = ioperm_active,
.regset_get = ioperm_get
},
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+ [REGSET64_SSP] = {
+ .core_note_type = NT_X86_SHSTK,
+ .n = 1,
+ .size = sizeof(u64),
+ .align = sizeof(u64),
+ .active = ssp_active,
+ .regset_get = ssp_get,
+ .set = ssp_set
+ },
+#endif
};
static const struct user_regset_view user_x86_64_view = {
diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
new file mode 100644
index 000000000000..fd689921a1db
--- /dev/null
+++ b/arch/x86/kernel/shstk.c
@@ -0,0 +1,550 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * shstk.c - Intel shadow stack support
+ *
+ * Copyright (c) 2021, Intel Corporation.
+ * Yu-cheng Yu <yu-cheng.yu@intel.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/sched/signal.h>
+#include <linux/compat.h>
+#include <linux/sizes.h>
+#include <linux/user.h>
+#include <linux/syscalls.h>
+#include <asm/msr.h>
+#include <asm/fpu/xstate.h>
+#include <asm/fpu/types.h>
+#include <asm/shstk.h>
+#include <asm/special_insns.h>
+#include <asm/fpu/api.h>
+#include <asm/prctl.h>
+
+#define SS_FRAME_SIZE 8
+
+static bool features_enabled(unsigned long features)
+{
+ return current->thread.features & features;
+}
+
+static void features_set(unsigned long features)
+{
+ current->thread.features |= features;
+}
+
+static void features_clr(unsigned long features)
+{
+ current->thread.features &= ~features;
+}
+
+/*
+ * Create a restore token on the shadow stack. A token is always 8-byte
+ * and aligned to 8.
+ */
+static int create_rstor_token(unsigned long ssp, unsigned long *token_addr)
+{
+ unsigned long addr;
+
+ /* Token must be aligned */
+ if (!IS_ALIGNED(ssp, 8))
+ return -EINVAL;
+
+ addr = ssp - SS_FRAME_SIZE;
+
+ /*
+ * SSP is aligned, so reserved bits and mode bit are a zero, just mark
+ * the token 64-bit.
+ */
+ ssp |= BIT(0);
+
+ if (write_user_shstk_64((u64 __user *)addr, (u64)ssp))
+ return -EFAULT;
+
+ if (token_addr)
+ *token_addr = addr;
+
+ return 0;
+}
+
+/*
+ * VM_SHADOW_STACK will have a guard page. This helps userspace protect
+ * itself from attacks. The reasoning is as follows:
+ *
+ * The shadow stack pointer(SSP) is moved by CALL, RET, and INCSSPQ. The
+ * INCSSP instruction can increment the shadow stack pointer. It is the
+ * shadow stack analog of an instruction like:
+ *
+ * addq $0x80, %rsp
+ *
+ * However, there is one important difference between an ADD on %rsp
+ * and INCSSP. In addition to modifying SSP, INCSSP also reads from the
+ * memory of the first and last elements that were "popped". It can be
+ * thought of as acting like this:
+ *
+ * READ_ONCE(ssp); // read+discard top element on stack
+ * ssp += nr_to_pop * 8; // move the shadow stack
+ * READ_ONCE(ssp-8); // read+discard last popped stack element
+ *
+ * The maximum distance INCSSP can move the SSP is 2040 bytes, before
+ * it would read the memory. Therefore a single page gap will be enough
+ * to prevent any operation from shifting the SSP to an adjacent stack,
+ * since it would have to land in the gap at least once, causing a
+ * fault.
+ */
+static unsigned long alloc_shstk(unsigned long addr, unsigned long size,
+ unsigned long token_offset, bool set_res_tok)
+{
+ int flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_ABOVE4G;
+ struct mm_struct *mm = current->mm;
+ unsigned long mapped_addr, unused;
+
+ if (addr)
+ flags |= MAP_FIXED_NOREPLACE;
+
+ mmap_write_lock(mm);
+ mapped_addr = do_mmap(NULL, addr, size, PROT_READ, flags,
+ VM_SHADOW_STACK | VM_WRITE, 0, &unused, NULL);
+ mmap_write_unlock(mm);
+
+ if (!set_res_tok || IS_ERR_VALUE(mapped_addr))
+ goto out;
+
+ if (create_rstor_token(mapped_addr + token_offset, NULL)) {
+ vm_munmap(mapped_addr, size);
+ return -EINVAL;
+ }
+
+out:
+ return mapped_addr;
+}
+
+static unsigned long adjust_shstk_size(unsigned long size)
+{
+ if (size)
+ return PAGE_ALIGN(size);
+
+ return PAGE_ALIGN(min_t(unsigned long long, rlimit(RLIMIT_STACK), SZ_4G));
+}
+
+static void unmap_shadow_stack(u64 base, u64 size)
+{
+ int r;
+
+ r = vm_munmap(base, size);
+
+ /*
+ * mmap_write_lock_killable() failed with -EINTR. This means
+ * the process is about to die and have it's MM cleaned up.
+ * This task shouldn't ever make it back to userspace. In this
+ * case it is ok to leak a shadow stack, so just exit out.
+ */
+ if (r == -EINTR)
+ return;
+
+ /*
+ * For all other types of vm_munmap() failure, either the
+ * system is out of memory or there is bug.
+ */
+ WARN_ON_ONCE(r);
+}
+
+static int shstk_setup(void)
+{
+ struct thread_shstk *shstk = &current->thread.shstk;
+ unsigned long addr, size;
+
+ /* Already enabled */
+ if (features_enabled(ARCH_SHSTK_SHSTK))
+ return 0;
+
+ /* Also not supported for 32 bit and x32 */
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) || in_32bit_syscall())
+ return -EOPNOTSUPP;
+
+ size = adjust_shstk_size(0);
+ addr = alloc_shstk(0, size, 0, false);
+ if (IS_ERR_VALUE(addr))
+ return PTR_ERR((void *)addr);
+
+ fpregs_lock_and_load();
+ wrmsrl(MSR_IA32_PL3_SSP, addr + size);
+ wrmsrl(MSR_IA32_U_CET, CET_SHSTK_EN);
+ fpregs_unlock();
+
+ shstk->base = addr;
+ shstk->size = size;
+ features_set(ARCH_SHSTK_SHSTK);
+
+ return 0;
+}
+
+void reset_thread_features(void)
+{
+ memset(&current->thread.shstk, 0, sizeof(struct thread_shstk));
+ current->thread.features = 0;
+ current->thread.features_locked = 0;
+}
+
+unsigned long shstk_alloc_thread_stack(struct task_struct *tsk, unsigned long clone_flags,
+ unsigned long stack_size)
+{
+ struct thread_shstk *shstk = &tsk->thread.shstk;
+ unsigned long addr, size;
+
+ /*
+ * If shadow stack is not enabled on the new thread, skip any
+ * switch to a new shadow stack.
+ */
+ if (!features_enabled(ARCH_SHSTK_SHSTK))
+ return 0;
+
+ /*
+ * For CLONE_VM, except vfork, the child needs a separate shadow
+ * stack.
+ */
+ if ((clone_flags & (CLONE_VFORK | CLONE_VM)) != CLONE_VM)
+ return 0;
+
+ size = adjust_shstk_size(stack_size);
+ addr = alloc_shstk(0, size, 0, false);
+ if (IS_ERR_VALUE(addr))
+ return addr;
+
+ shstk->base = addr;
+ shstk->size = size;
+
+ return addr + size;
+}
+
+static unsigned long get_user_shstk_addr(void)
+{
+ unsigned long long ssp;
+
+ fpregs_lock_and_load();
+
+ rdmsrl(MSR_IA32_PL3_SSP, ssp);
+
+ fpregs_unlock();
+
+ return ssp;
+}
+
+#define SHSTK_DATA_BIT BIT(63)
+
+static int put_shstk_data(u64 __user *addr, u64 data)
+{
+ if (WARN_ON_ONCE(data & SHSTK_DATA_BIT))
+ return -EINVAL;
+
+ /*
+ * Mark the high bit so that the sigframe can't be processed as a
+ * return address.
+ */
+ if (write_user_shstk_64(addr, data | SHSTK_DATA_BIT))
+ return -EFAULT;
+ return 0;
+}
+
+static int get_shstk_data(unsigned long *data, unsigned long __user *addr)
+{
+ unsigned long ldata;
+
+ if (unlikely(get_user(ldata, addr)))
+ return -EFAULT;
+
+ if (!(ldata & SHSTK_DATA_BIT))
+ return -EINVAL;
+
+ *data = ldata & ~SHSTK_DATA_BIT;
+
+ return 0;
+}
+
+static int shstk_push_sigframe(unsigned long *ssp)
+{
+ unsigned long target_ssp = *ssp;
+
+ /* Token must be aligned */
+ if (!IS_ALIGNED(target_ssp, 8))
+ return -EINVAL;
+
+ *ssp -= SS_FRAME_SIZE;
+ if (put_shstk_data((void __user *)*ssp, target_ssp))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int shstk_pop_sigframe(unsigned long *ssp)
+{
+ struct vm_area_struct *vma;
+ unsigned long token_addr;
+ bool need_to_check_vma;
+ int err = 1;
+
+ /*
+ * It is possible for the SSP to be off the end of a shadow stack by 4
+ * or 8 bytes. If the shadow stack is at the start of a page or 4 bytes
+ * before it, it might be this case, so check that the address being
+ * read is actually shadow stack.
+ */
+ if (!IS_ALIGNED(*ssp, 8))
+ return -EINVAL;
+
+ need_to_check_vma = PAGE_ALIGN(*ssp) == *ssp;
+
+ if (need_to_check_vma)
+ mmap_read_lock_killable(current->mm);
+
+ err = get_shstk_data(&token_addr, (unsigned long __user *)*ssp);
+ if (unlikely(err))
+ goto out_err;
+
+ if (need_to_check_vma) {
+ vma = find_vma(current->mm, *ssp);
+ if (!vma || !(vma->vm_flags & VM_SHADOW_STACK)) {
+ err = -EFAULT;
+ goto out_err;
+ }
+
+ mmap_read_unlock(current->mm);
+ }
+
+ /* Restore SSP aligned? */
+ if (unlikely(!IS_ALIGNED(token_addr, 8)))
+ return -EINVAL;
+
+ /* SSP in userspace? */
+ if (unlikely(token_addr >= TASK_SIZE_MAX))
+ return -EINVAL;
+
+ *ssp = token_addr;
+
+ return 0;
+out_err:
+ if (need_to_check_vma)
+ mmap_read_unlock(current->mm);
+ return err;
+}
+
+int setup_signal_shadow_stack(struct ksignal *ksig)
+{
+ void __user *restorer = ksig->ka.sa.sa_restorer;
+ unsigned long ssp;
+ int err;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) ||
+ !features_enabled(ARCH_SHSTK_SHSTK))
+ return 0;
+
+ if (!restorer)
+ return -EINVAL;
+
+ ssp = get_user_shstk_addr();
+ if (unlikely(!ssp))
+ return -EINVAL;
+
+ err = shstk_push_sigframe(&ssp);
+ if (unlikely(err))
+ return err;
+
+ /* Push restorer address */
+ ssp -= SS_FRAME_SIZE;
+ err = write_user_shstk_64((u64 __user *)ssp, (u64)restorer);
+ if (unlikely(err))
+ return -EFAULT;
+
+ fpregs_lock_and_load();
+ wrmsrl(MSR_IA32_PL3_SSP, ssp);
+ fpregs_unlock();
+
+ return 0;
+}
+
+int restore_signal_shadow_stack(void)
+{
+ unsigned long ssp;
+ int err;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) ||
+ !features_enabled(ARCH_SHSTK_SHSTK))
+ return 0;
+
+ ssp = get_user_shstk_addr();
+ if (unlikely(!ssp))
+ return -EINVAL;
+
+ err = shstk_pop_sigframe(&ssp);
+ if (unlikely(err))
+ return err;
+
+ fpregs_lock_and_load();
+ wrmsrl(MSR_IA32_PL3_SSP, ssp);
+ fpregs_unlock();
+
+ return 0;
+}
+
+void shstk_free(struct task_struct *tsk)
+{
+ struct thread_shstk *shstk = &tsk->thread.shstk;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) ||
+ !features_enabled(ARCH_SHSTK_SHSTK))
+ return;
+
+ /*
+ * When fork() with CLONE_VM fails, the child (tsk) already has a
+ * shadow stack allocated, and exit_thread() calls this function to
+ * free it. In this case the parent (current) and the child share
+ * the same mm struct.
+ */
+ if (!tsk->mm || tsk->mm != current->mm)
+ return;
+
+ unmap_shadow_stack(shstk->base, shstk->size);
+}
+
+static int wrss_control(bool enable)
+{
+ u64 msrval;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK))
+ return -EOPNOTSUPP;
+
+ /*
+ * Only enable WRSS if shadow stack is enabled. If shadow stack is not
+ * enabled, WRSS will already be disabled, so don't bother clearing it
+ * when disabling.
+ */
+ if (!features_enabled(ARCH_SHSTK_SHSTK))
+ return -EPERM;
+
+ /* Already enabled/disabled? */
+ if (features_enabled(ARCH_SHSTK_WRSS) == enable)
+ return 0;
+
+ fpregs_lock_and_load();
+ rdmsrl(MSR_IA32_U_CET, msrval);
+
+ if (enable) {
+ features_set(ARCH_SHSTK_WRSS);
+ msrval |= CET_WRSS_EN;
+ } else {
+ features_clr(ARCH_SHSTK_WRSS);
+ if (!(msrval & CET_WRSS_EN))
+ goto unlock;
+
+ msrval &= ~CET_WRSS_EN;
+ }
+
+ wrmsrl(MSR_IA32_U_CET, msrval);
+
+unlock:
+ fpregs_unlock();
+
+ return 0;
+}
+
+static int shstk_disable(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK))
+ return -EOPNOTSUPP;
+
+ /* Already disabled? */
+ if (!features_enabled(ARCH_SHSTK_SHSTK))
+ return 0;
+
+ fpregs_lock_and_load();
+ /* Disable WRSS too when disabling shadow stack */
+ wrmsrl(MSR_IA32_U_CET, 0);
+ wrmsrl(MSR_IA32_PL3_SSP, 0);
+ fpregs_unlock();
+
+ shstk_free(current);
+ features_clr(ARCH_SHSTK_SHSTK | ARCH_SHSTK_WRSS);
+
+ return 0;
+}
+
+SYSCALL_DEFINE3(map_shadow_stack, unsigned long, addr, unsigned long, size, unsigned int, flags)
+{
+ bool set_tok = flags & SHADOW_STACK_SET_TOKEN;
+ unsigned long aligned_size;
+
+ if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK))
+ return -EOPNOTSUPP;
+
+ if (flags & ~SHADOW_STACK_SET_TOKEN)
+ return -EINVAL;
+
+ /* If there isn't space for a token */
+ if (set_tok && size < 8)
+ return -ENOSPC;
+
+ if (addr && addr < SZ_4G)
+ return -ERANGE;
+
+ /*
+ * An overflow would result in attempting to write the restore token
+ * to the wrong location. Not catastrophic, but just return the right
+ * error code and block it.
+ */
+ aligned_size = PAGE_ALIGN(size);
+ if (aligned_size < size)
+ return -EOVERFLOW;
+
+ return alloc_shstk(addr, aligned_size, size, set_tok);
+}
+
+long shstk_prctl(struct task_struct *task, int option, unsigned long arg2)
+{
+ unsigned long features = arg2;
+
+ if (option == ARCH_SHSTK_STATUS) {
+ return put_user(task->thread.features, (unsigned long __user *)arg2);
+ }
+
+ if (option == ARCH_SHSTK_LOCK) {
+ task->thread.features_locked |= features;
+ return 0;
+ }
+
+ /* Only allow via ptrace */
+ if (task != current) {
+ if (option == ARCH_SHSTK_UNLOCK && IS_ENABLED(CONFIG_CHECKPOINT_RESTORE)) {
+ task->thread.features_locked &= ~features;
+ return 0;
+ }
+ return -EINVAL;
+ }
+
+ /* Do not allow to change locked features */
+ if (features & task->thread.features_locked)
+ return -EPERM;
+
+ /* Only support enabling/disabling one feature at a time. */
+ if (hweight_long(features) > 1)
+ return -EINVAL;
+
+ if (option == ARCH_SHSTK_DISABLE) {
+ if (features & ARCH_SHSTK_WRSS)
+ return wrss_control(false);
+ if (features & ARCH_SHSTK_SHSTK)
+ return shstk_disable();
+ return -EINVAL;
+ }
+
+ /* Handle ARCH_SHSTK_ENABLE */
+ if (features & ARCH_SHSTK_SHSTK)
+ return shstk_setup();
+ if (features & ARCH_SHSTK_WRSS)
+ return wrss_control(true);
+ return -EINVAL;
+}
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index cfeec3ee877e..65fe2094da59 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -40,6 +40,7 @@
#include <asm/syscall.h>
#include <asm/sigframe.h>
#include <asm/signal.h>
+#include <asm/shstk.h>
static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 9027fc088f97..c12624bc82a3 100644
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -402,7 +402,7 @@ Efault:
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 13a1e6083837..cacf2ede6217 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -175,6 +175,9 @@ int x64_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe), &fp);
uc_flags = frame_uc_flags(regs);
+ if (setup_signal_shadow_stack(ksig))
+ return -EFAULT;
+
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;
@@ -260,6 +263,9 @@ SYSCALL_DEFINE0(rt_sigreturn)
if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
goto badframe;
+ if (restore_signal_shadow_stack())
+ goto badframe;
+
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
@@ -403,7 +409,7 @@ void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
-static_assert(NSIGSEGV == 9);
+static_assert(NSIGSEGV == 10);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 8cc653ffdccd..c783aeb37dce 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -193,7 +193,11 @@ get_unmapped_area:
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
- info.low_limit = PAGE_SIZE;
+ if (!in_32bit_syscall() && (flags & MAP_ABOVE4G))
+ info.low_limit = SZ_4G;
+ else
+ info.low_limit = PAGE_SIZE;
+
info.high_limit = get_mmap_base(0);
/*
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 4a817d20ce3b..c876f1d36a81 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -77,18 +77,6 @@
DECLARE_BITMAP(system_vectors, NR_VECTORS);
-static inline void cond_local_irq_enable(struct pt_regs *regs)
-{
- if (regs->flags & X86_EFLAGS_IF)
- local_irq_enable();
-}
-
-static inline void cond_local_irq_disable(struct pt_regs *regs)
-{
- if (regs->flags & X86_EFLAGS_IF)
- local_irq_disable();
-}
-
__always_inline int is_valid_bugaddr(unsigned long addr)
{
if (addr < TASK_SIZE_MAX)
@@ -213,81 +201,6 @@ DEFINE_IDTENTRY(exc_overflow)
do_error_trap(regs, 0, "overflow", X86_TRAP_OF, SIGSEGV, 0, NULL);
}
-#ifdef CONFIG_X86_KERNEL_IBT
-
-static __ro_after_init bool ibt_fatal = true;
-
-extern void ibt_selftest_ip(void); /* code label defined in asm below */
-
-enum cp_error_code {
- CP_EC = (1 << 15) - 1,
-
- CP_RET = 1,
- CP_IRET = 2,
- CP_ENDBR = 3,
- CP_RSTRORSSP = 4,
- CP_SETSSBSY = 5,
-
- CP_ENCL = 1 << 15,
-};
-
-DEFINE_IDTENTRY_ERRORCODE(exc_control_protection)
-{
- if (!cpu_feature_enabled(X86_FEATURE_IBT)) {
- pr_err("Unexpected #CP\n");
- BUG();
- }
-
- if (WARN_ON_ONCE(user_mode(regs) || (error_code & CP_EC) != CP_ENDBR))
- return;
-
- if (unlikely(regs->ip == (unsigned long)&ibt_selftest_ip)) {
- regs->ax = 0;
- return;
- }
-
- pr_err("Missing ENDBR: %pS\n", (void *)instruction_pointer(regs));
- if (!ibt_fatal) {
- printk(KERN_DEFAULT CUT_HERE);
- __warn(__FILE__, __LINE__, (void *)regs->ip, TAINT_WARN, regs, NULL);
- return;
- }
- BUG();
-}
-
-/* Must be noinline to ensure uniqueness of ibt_selftest_ip. */
-noinline bool ibt_selftest(void)
-{
- unsigned long ret;
-
- asm (" lea ibt_selftest_ip(%%rip), %%rax\n\t"
- ANNOTATE_RETPOLINE_SAFE
- " jmp *%%rax\n\t"
- "ibt_selftest_ip:\n\t"
- UNWIND_HINT_FUNC
- ANNOTATE_NOENDBR
- " nop\n\t"
-
- : "=a" (ret) : : "memory");
-
- return !ret;
-}
-
-static int __init ibt_setup(char *str)
-{
- if (!strcmp(str, "off"))
- setup_clear_cpu_cap(X86_FEATURE_IBT);
-
- if (!strcmp(str, "warn"))
- ibt_fatal = false;
-
- return 1;
-}
-
-__setup("ibt=", ibt_setup);
-
-#endif /* CONFIG_X86_KERNEL_IBT */
-
#ifdef CONFIG_X86_F00F_BUG
void handle_invalid_op(struct pt_regs *regs)
#else
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 2e861b9360c7..ab778eac1952 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1112,8 +1112,22 @@ access_error(unsigned long error_code, struct vm_area_struct *vma)
(error_code & X86_PF_INSTR), foreign))
return 1;
+ /*
+ * Shadow stack accesses (PF_SHSTK=1) are only permitted to
+ * shadow stack VMAs. All other accesses result in an error.
+ */
+ if (error_code & X86_PF_SHSTK) {
+ if (unlikely(!(vma->vm_flags & VM_SHADOW_STACK)))
+ return 1;
+ if (unlikely(!(vma->vm_flags & VM_WRITE)))
+ return 1;
+ return 0;
+ }
+
if (error_code & X86_PF_WRITE) {
/* write, present and write, not present: */
+ if (unlikely(vma->vm_flags & VM_SHADOW_STACK))
+ return 1;
if (unlikely(!(vma->vm_flags & VM_WRITE)))
return 1;
return 0;
@@ -1305,6 +1319,14 @@ void do_user_addr_fault(struct pt_regs *regs,
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+ /*
+ * Read-only permissions can not be expressed in shadow stack PTEs.
+ * Treat all shadow stack accesses as WRITE faults. This ensures
+ * that the MM will prepare everything (e.g., break COW) such that
+ * maybe_mkwrite() can create a proper shadow stack PTE.
+ */
+ if (error_code & X86_PF_SHSTK)
+ flags |= FAULT_FLAG_WRITE;
if (error_code & X86_PF_WRITE)
flags |= FAULT_FLAG_WRITE;
if (error_code & X86_PF_INSTR)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index df4182b6449f..bda9f129835e 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2074,12 +2074,12 @@ int set_memory_nx(unsigned long addr, int numpages)
int set_memory_ro(unsigned long addr, int numpages)
{
- return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW), 0);
+ return change_page_attr_clear(&addr, numpages, __pgprot(_PAGE_RW | _PAGE_DIRTY), 0);
}
int set_memory_rox(unsigned long addr, int numpages)
{
- pgprot_t clr = __pgprot(_PAGE_RW);
+ pgprot_t clr = __pgprot(_PAGE_RW | _PAGE_DIRTY);
if (__supported_pte_mask & _PAGE_NX)
clr.pgprot |= _PAGE_NX;
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index d3a93e8766ee..9deadf517f14 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -881,3 +881,43 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
#endif /* CONFIG_X86_64 */
#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+
+pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & VM_SHADOW_STACK)
+ return pte_mkwrite_shstk(pte);
+
+ pte = pte_mkwrite_novma(pte);
+
+ return pte_clear_saveddirty(pte);
+}
+
+pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & VM_SHADOW_STACK)
+ return pmd_mkwrite_shstk(pmd);
+
+ pmd = pmd_mkwrite_novma(pmd);
+
+ return pmd_clear_saveddirty(pmd);
+}
+
+void arch_check_zapped_pte(struct vm_area_struct *vma, pte_t pte)
+{
+ /*
+ * Hardware before shadow stack can (rarely) set Dirty=1
+ * on a Write=0 PTE. So the below condition
+ * only indicates a software bug when shadow stack is
+ * supported by the HW. This checking is covered in
+ * pte_shstk().
+ */
+ VM_WARN_ON_ONCE(!(vma->vm_flags & VM_SHADOW_STACK) &&
+ pte_shstk(pte));
+}
+
+void arch_check_zapped_pmd(struct vm_area_struct *vma, pmd_t pmd)
+{
+ /* See note in arch_check_zapped_pte() */
+ VM_WARN_ON_ONCE(!(vma->vm_flags & VM_SHADOW_STACK) &&
+ pmd_shstk(pmd));
+}
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 3e04f2b3c27e..49352fad7d1d 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -694,7 +694,7 @@ static struct trap_array_entry trap_array[] = {
TRAP_ENTRY(exc_coprocessor_error, false ),
TRAP_ENTRY(exc_alignment_check, false ),
TRAP_ENTRY(exc_simd_coprocessor_error, false ),
-#ifdef CONFIG_X86_KERNEL_IBT
+#ifdef CONFIG_X86_CET
TRAP_ENTRY(exc_control_protection, false ),
#endif
};
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 1b5cba70c236..1652c39e3dfb 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -166,7 +166,7 @@ void make_lowmem_page_readwrite(void *vaddr)
if (pte == NULL)
return; /* vaddr missing */
- ptev = pte_mkwrite(*pte);
+ ptev = pte_mkwrite_novma(*pte);
if (HYPERVISOR_update_va_mapping(address, ptev, 0))
BUG();
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
index 08f1ceb9eb81..9e5e68008785 100644
--- a/arch/x86/xen/xen-asm.S
+++ b/arch/x86/xen/xen-asm.S
@@ -148,7 +148,7 @@ xen_pv_trap asm_exc_page_fault
xen_pv_trap asm_exc_spurious_interrupt_bug
xen_pv_trap asm_exc_coprocessor_error
xen_pv_trap asm_exc_alignment_check
-#ifdef CONFIG_X86_KERNEL_IBT
+#ifdef CONFIG_X86_CET
xen_pv_trap asm_exc_control_protection
#endif
#ifdef CONFIG_X86_MCE
diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index ef79cb6c20dc..9a7e5e57ee9a 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -262,7 +262,7 @@ static inline pte_t pte_mkdirty(pte_t pte)
{ pte_val(pte) |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte)
{ pte_val(pte) |= _PAGE_ACCESSED; return pte; }
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
{ pte_val(pte) |= _PAGE_WRITABLE; return pte; }
#define pgprot_noncached(prot) \
diff --git a/fs/aio.c b/fs/aio.c
index b3174da80ff6..a4c2a6bac72c 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -558,7 +558,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
PROT_READ | PROT_WRITE,
- MAP_SHARED, 0, &unused, NULL);
+ MAP_SHARED, 0, 0, &unused, NULL);
mmap_write_unlock(mm);
if (IS_ERR((void *)ctx->mmap_base)) {
ctx->mmap_size = 0;
diff --git a/fs/proc/array.c b/fs/proc/array.c
index d35bbf35a874..2c2efbe685d8 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -431,6 +431,11 @@ static inline void task_untag_mask(struct seq_file *m, struct mm_struct *mm)
seq_printf(m, "untag_mask:\t%#lx\n", mm_untag_mask(mm));
}
+__weak void arch_proc_pid_thread_features(struct seq_file *m,
+ struct task_struct *task)
+{
+}
+
int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
@@ -455,6 +460,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
task_cpus_allowed(m, task);
cpuset_task_status_allowed(m, task);
task_context_switch_counts(m, task);
+ arch_proc_pid_thread_features(m, task);
return 0;
}
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 15ddf4653a19..0f2aa36a9913 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -692,6 +692,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
[ilog2(VM_UFFD_MINOR)] = "ui",
#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+ [ilog2(VM_SHADOW_STACK)] = "ss",
+#endif
};
size_t i;
diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
index d7f6335d3999..4da02798a00b 100644
--- a/include/asm-generic/hugetlb.h
+++ b/include/asm-generic/hugetlb.h
@@ -22,7 +22,7 @@ static inline unsigned long huge_pte_dirty(pte_t pte)
static inline pte_t huge_pte_mkwrite(pte_t pte)
{
- return pte_mkwrite(pte);
+ return pte_mkwrite_novma(pte);
}
#ifndef __HAVE_ARCH_HUGE_PTE_WRPROTECT
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 20e6d1dde412..bf5d0b1b16f4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -319,11 +319,13 @@ extern unsigned int kobjsize(const void *objp);
#define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */
+#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */
#define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0)
#define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1)
#define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2)
#define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3)
#define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4)
+#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5)
#endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
#ifdef CONFIG_ARCH_HAS_PKEYS
@@ -339,6 +341,21 @@ extern unsigned int kobjsize(const void *objp);
#endif
#endif /* CONFIG_ARCH_HAS_PKEYS */
+#ifdef CONFIG_X86_USER_SHADOW_STACK
+/*
+ * VM_SHADOW_STACK should not be set with VM_SHARED because of lack of
+ * support core mm.
+ *
+ * These VMAs will get a single end guard page. This helps userspace protect
+ * itself from attacks. A single page is enough for current shadow stack archs
+ * (x86). See the comments near alloc_shstk() in arch/x86/kernel/shstk.c
+ * for more details on the guard size.
+ */
+# define VM_SHADOW_STACK VM_HIGH_ARCH_5
+#else
+# define VM_SHADOW_STACK VM_NONE
+#endif
+
#if defined(CONFIG_X86)
# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */
#elif defined(CONFIG_PPC)
@@ -370,7 +387,7 @@ extern unsigned int kobjsize(const void *objp);
#endif
#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
-# define VM_UFFD_MINOR_BIT 37
+# define VM_UFFD_MINOR_BIT 38
# define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */
#else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
# define VM_UFFD_MINOR VM_NONE
@@ -397,6 +414,8 @@ extern unsigned int kobjsize(const void *objp);
#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
#endif
+#define VM_STARTGAP_FLAGS (VM_GROWSDOWN | VM_SHADOW_STACK)
+
#ifdef CONFIG_STACK_GROWSUP
#define VM_STACK VM_GROWSUP
#define VM_STACK_EARLY VM_GROWSDOWN
@@ -1309,7 +1328,7 @@ static inline unsigned long thp_size(struct page *page)
static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
{
if (likely(vma->vm_flags & VM_WRITE))
- pte = pte_mkwrite(pte);
+ pte = pte_mkwrite(pte, vma);
return pte;
}
@@ -3265,7 +3284,8 @@ extern unsigned long mmap_region(struct file *file, unsigned long addr,
struct list_head *uf);
extern unsigned long do_mmap(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot, unsigned long flags,
- unsigned long pgoff, unsigned long *populate, struct list_head *uf);
+ vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate,
+ struct list_head *uf);
extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
unsigned long start, size_t len, struct list_head *uf,
bool unlock);
@@ -3353,15 +3373,26 @@ struct vm_area_struct *vma_lookup(struct mm_struct *mm, unsigned long addr)
return mtree_load(&mm->mm_mt, addr);
}
+static inline unsigned long stack_guard_start_gap(struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & VM_GROWSDOWN)
+ return stack_guard_gap;
+
+ /* See reasoning around the VM_SHADOW_STACK definition */
+ if (vma->vm_flags & VM_SHADOW_STACK)
+ return PAGE_SIZE;
+
+ return 0;
+}
+
static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
{
+ unsigned long gap = stack_guard_start_gap(vma);
unsigned long vm_start = vma->vm_start;
- if (vma->vm_flags & VM_GROWSDOWN) {
- vm_start -= stack_guard_gap;
- if (vm_start > vma->vm_start)
- vm_start = 0;
- }
+ vm_start -= gap;
+ if (vm_start > vma->vm_start)
+ vm_start = 0;
return vm_start;
}
diff --git a/include/linux/mman.h b/include/linux/mman.h
index cee1e4b566d8..40d94411d492 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -15,6 +15,9 @@
#ifndef MAP_32BIT
#define MAP_32BIT 0
#endif
+#ifndef MAP_ABOVE4G
+#define MAP_ABOVE4G 0
+#endif
#ifndef MAP_HUGE_2MB
#define MAP_HUGE_2MB 0
#endif
@@ -50,6 +53,7 @@
| MAP_STACK \
| MAP_HUGETLB \
| MAP_32BIT \
+ | MAP_ABOVE4G \
| MAP_HUGE_2MB \
| MAP_HUGE_1GB)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index f49abcfe5eda..1fba072b3dac 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -371,6 +371,20 @@ static inline bool arch_has_hw_pte_young(void)
}
#endif
+#ifndef arch_check_zapped_pte
+static inline void arch_check_zapped_pte(struct vm_area_struct *vma,
+ pte_t pte)
+{
+}
+#endif
+
+#ifndef arch_check_zapped_pmd
+static inline void arch_check_zapped_pmd(struct vm_area_struct *vma,
+ pmd_t pmd)
+{
+}
+#endif
+
#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
unsigned long address,
@@ -577,6 +591,20 @@ extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma,
pud_t *pudp);
#endif
+#ifndef pte_mkwrite
+static inline pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)
+{
+ return pte_mkwrite_novma(pte);
+}
+#endif
+
+#if defined(CONFIG_ARCH_WANT_PMD_MKWRITE) && !defined(pmd_mkwrite)
+static inline pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
+{
+ return pmd_mkwrite_novma(pmd);
+}
+#endif
+
#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
struct mm_struct;
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 253f2676d93a..de407e7c3b55 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -159,6 +159,7 @@ int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns,
#endif /* CONFIG_PROC_PID_ARCH_STATUS */
void arch_report_meminfo(struct seq_file *m);
+void arch_proc_pid_thread_features(struct seq_file *m, struct task_struct *task);
#else /* CONFIG_PROC_FS */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c0cb22cd607d..22bc6bc147f8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -939,6 +939,7 @@ asmlinkage long sys_set_mempolicy_home_node(unsigned long start, unsigned long l
asmlinkage long sys_cachestat(unsigned int fd,
struct cachestat_range __user *cstat_range,
struct cachestat __user *cstat, unsigned int flags);
+asmlinkage long sys_map_shadow_stack(unsigned long addr, unsigned long size, unsigned int flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index ffbe4cec9f32..0f52d0ac47c5 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -242,7 +242,8 @@ typedef struct siginfo {
#define SEGV_ADIPERR 7 /* Precise MCD exception */
#define SEGV_MTEAERR 8 /* Asynchronous ARM MTE error */
#define SEGV_MTESERR 9 /* Synchronous ARM MTE exception */
-#define NSIGSEGV 9
+#define SEGV_CPERR 10 /* Control protection fault */
+#define NSIGSEGV 10
/*
* SIGBUS si_codes
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index e0e159138331..ee0bcff14b69 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -409,6 +409,8 @@ typedef struct elf64_shdr {
#define NT_386_TLS 0x200 /* i386 TLS slots (struct user_desc) */
#define NT_386_IOPERM 0x201 /* x86 io permission bitmap (1=deny) */
#define NT_X86_XSTATE 0x202 /* x86 extended state using xsave */
+/* Old binutils treats 0x203 as a CET state */
+#define NT_X86_SHSTK 0x204 /* x86 SHSTK state */
#define NT_S390_HIGH_GPRS 0x300 /* s390 upper register halves */
#define NT_S390_TIMER 0x301 /* s390 timer register */
#define NT_S390_TODCMP 0x302 /* s390 TOD clock comparator register */
diff --git a/ipc/shm.c b/ipc/shm.c
index 60e45e7045d4..576a543b7cff 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1662,7 +1662,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
goto invalid;
}
- addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
+ addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
*raddr = addr;
err = 0;
if (IS_ERR_VALUE(addr))
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 781de7cc6a4e..e137c1385c56 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -274,6 +274,7 @@ COND_SYSCALL(vm86old);
COND_SYSCALL(modify_ldt);
COND_SYSCALL(vm86);
COND_SYSCALL(kexec_file_load);
+COND_SYSCALL(map_shadow_stack);
/* s390 */
COND_SYSCALL(s390_pci_mmio_read);
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index d61eaa075c75..48e329ea5ba3 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -109,10 +109,10 @@ static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
WARN_ON(!pte_same(pte, pte));
WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte))));
WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte))));
- WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte))));
+ WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte), args->vma)));
WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte))));
WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte))));
- WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte))));
+ WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte, args->vma))));
WARN_ON(pte_dirty(pte_wrprotect(pte_mkclean(pte))));
WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte))));
}
@@ -156,7 +156,7 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args)
pte = pte_mkclean(pte);
set_pte_at(args->mm, args->vaddr, args->ptep, pte);
flush_dcache_page(page);
- pte = pte_mkwrite(pte);
+ pte = pte_mkwrite(pte, args->vma);
pte = pte_mkdirty(pte);
ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1);
pte = ptep_get(args->ptep);
@@ -202,10 +202,10 @@ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
WARN_ON(!pmd_same(pmd, pmd));
WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd))));
WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd))));
- WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd))));
+ WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd), args->vma)));
WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd))));
WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd))));
- WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd))));
+ WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd, args->vma))));
WARN_ON(pmd_dirty(pmd_wrprotect(pmd_mkclean(pmd))));
WARN_ON(!pmd_dirty(pmd_wrprotect(pmd_mkdirty(pmd))));
/*
@@ -256,7 +256,7 @@ static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
pmd = pmd_mkclean(pmd);
set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
flush_dcache_page(page);
- pmd = pmd_mkwrite(pmd);
+ pmd = pmd_mkwrite(pmd, args->vma);
pmd = pmd_mkdirty(pmd);
pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1);
pmd = READ_ONCE(*args->pmdp);
diff --git a/mm/gup.c b/mm/gup.c
index 948f3b454b00..2f8a2d89fde1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1051,7 +1051,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
!writable_file_mapping_allowed(vma, gup_flags))
return -EFAULT;
- if (!(vm_flags & VM_WRITE)) {
+ if (!(vm_flags & VM_WRITE) || (vm_flags & VM_SHADOW_STACK)) {
if (!(gup_flags & FOLL_FORCE))
return -EFAULT;
/* hugetlb does not support FOLL_FORCE|FOLL_WRITE. */
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index fcafd9b69665..064fbd90822b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -551,7 +551,7 @@ __setup("transparent_hugepage=", setup_transparent_hugepage);
pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
{
if (likely(vma->vm_flags & VM_WRITE))
- pmd = pmd_mkwrite(pmd);
+ pmd = pmd_mkwrite(pmd, vma);
return pmd;
}
@@ -1566,7 +1566,7 @@ out_map:
pmd = pmd_modify(oldpmd, vma->vm_page_prot);
pmd = pmd_mkyoung(pmd);
if (writable)
- pmd = pmd_mkwrite(pmd);
+ pmd = pmd_mkwrite(pmd, vma);
set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd);
update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
spin_unlock(vmf->ptl);
@@ -1675,6 +1675,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
*/
orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd,
tlb->fullmm);
+ arch_check_zapped_pmd(vma, orig_pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
if (vma_is_special_huge(vma)) {
if (arch_needs_pgtable_deposit())
@@ -1919,7 +1920,7 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
/* See change_pte_range(). */
if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) && !pmd_write(entry) &&
can_change_pmd_writable(vma, addr, entry))
- entry = pmd_mkwrite(entry);
+ entry = pmd_mkwrite(entry, vma);
ret = HPAGE_PMD_NR;
set_pmd_at(mm, addr, pmd, entry);
@@ -2233,7 +2234,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
} else {
entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot));
if (write)
- entry = pte_mkwrite(entry);
+ entry = pte_mkwrite(entry, vma);
if (anon_exclusive)
SetPageAnonExclusive(page + i);
if (!young)
@@ -3265,7 +3266,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
if (pmd_swp_soft_dirty(*pvmw->pmd))
pmde = pmd_mksoft_dirty(pmde);
if (is_writable_migration_entry(entry))
- pmde = pmd_mkwrite(pmde);
+ pmde = pmd_mkwrite(pmde, vma);
if (pmd_swp_uffd_wp(*pvmw->pmd))
pmde = pmd_mkuffd_wp(pmde);
if (!is_migration_entry_young(entry))
diff --git a/mm/internal.h b/mm/internal.h
index d1d4bf4e63c0..30cf724ddbce 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -556,14 +556,14 @@ static inline bool is_exec_mapping(vm_flags_t flags)
}
/*
- * Stack area - automatically grows in one direction
+ * Stack area (including shadow stacks)
*
* VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
* do_mmap() forbids all other combinations.
*/
static inline bool is_stack_mapping(vm_flags_t flags)
{
- return (flags & VM_STACK) == VM_STACK;
+ return ((flags & VM_STACK) == VM_STACK) || (flags & VM_SHADOW_STACK);
}
/*
diff --git a/mm/memory.c b/mm/memory.c
index 405a483d2fd1..6c264d2f969c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1430,6 +1430,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
continue;
ptent = ptep_get_and_clear_full(mm, addr, pte,
tlb->fullmm);
+ arch_check_zapped_pte(vma, ptent);
tlb_remove_tlb_entry(tlb, pte, addr);
zap_install_uffd_wp_if_needed(vma, addr, pte, details,
ptent);
@@ -4124,7 +4125,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
entry = mk_pte(&folio->page, vma->vm_page_prot);
entry = pte_sw_mkyoung(entry);
if (vma->vm_flags & VM_WRITE)
- entry = pte_mkwrite(pte_mkdirty(entry));
+ entry = pte_mkwrite(pte_mkdirty(entry), vma);
vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
&vmf->ptl);
@@ -4842,7 +4843,7 @@ out_map:
pte = pte_modify(old_pte, vma->vm_page_prot);
pte = pte_mkyoung(pte);
if (writable)
- pte = pte_mkwrite(pte);
+ pte = pte_mkwrite(pte, vma);
ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1);
pte_unmap_unlock(vmf->pte, vmf->ptl);
diff --git a/mm/migrate.c b/mm/migrate.c
index 78c9bd505b62..b7fa020003f3 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -220,7 +220,7 @@ static bool remove_migration_pte(struct folio *folio,
if (folio_test_dirty(folio) && is_migration_entry_dirty(entry))
pte = pte_mkdirty(pte);
if (is_writable_migration_entry(entry))
- pte = pte_mkwrite(pte);
+ pte = pte_mkwrite(pte, vma);
else if (pte_swp_uffd_wp(old_pte))
pte = pte_mkuffd_wp(pte);
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index d69131adc51c..8ac1f79f754a 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -624,7 +624,7 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
}
entry = mk_pte(page, vma->vm_page_prot);
if (vma->vm_flags & VM_WRITE)
- entry = pte_mkwrite(pte_mkdirty(entry));
+ entry = pte_mkwrite(pte_mkdirty(entry), vma);
}
ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
diff --git a/mm/mmap.c b/mm/mmap.c
index 514ced13c65c..b56a7f0c9f85 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1182,11 +1182,11 @@ static inline bool file_mmap_ok(struct file *file, struct inode *inode,
*/
unsigned long do_mmap(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot,
- unsigned long flags, unsigned long pgoff,
- unsigned long *populate, struct list_head *uf)
+ unsigned long flags, vm_flags_t vm_flags,
+ unsigned long pgoff, unsigned long *populate,
+ struct list_head *uf)
{
struct mm_struct *mm = current->mm;
- vm_flags_t vm_flags;
int pkey = 0;
*populate = 0;
@@ -1246,7 +1246,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
*/
- vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
+ vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
if (flags & MAP_LOCKED)
@@ -1564,7 +1564,7 @@ retry:
gap = mas.index;
gap += (info->align_offset - gap) & info->align_mask;
tmp = mas_next(&mas, ULONG_MAX);
- if (tmp && (tmp->vm_flags & VM_GROWSDOWN)) { /* Avoid prev check if possible */
+ if (tmp && (tmp->vm_flags & VM_STARTGAP_FLAGS)) { /* Avoid prev check if possible */
if (vm_start_gap(tmp) < gap + length - 1) {
low_limit = tmp->vm_end;
mas_reset(&mas);
@@ -1616,7 +1616,7 @@ retry:
gap -= (gap - info->align_offset) & info->align_mask;
gap_end = mas.last;
tmp = mas_next(&mas, ULONG_MAX);
- if (tmp && (tmp->vm_flags & VM_GROWSDOWN)) { /* Avoid prev check if possible */
+ if (tmp && (tmp->vm_flags & VM_STARTGAP_FLAGS)) { /* Avoid prev check if possible */
if (vm_start_gap(tmp) <= gap_end) {
high_limit = vm_start_gap(tmp);
mas_reset(&mas);
@@ -2998,7 +2998,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
file = get_file(vma->vm_file);
ret = do_mmap(vma->vm_file, start, size,
- prot, flags, pgoff, &populate, NULL);
+ prot, flags, 0, pgoff, &populate, NULL);
fput(file);
out:
mmap_write_unlock(mm);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 130db91d3a8c..b94fbb45d5c7 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -185,7 +185,7 @@ static long change_pte_range(struct mmu_gather *tlb,
if ((cp_flags & MM_CP_TRY_CHANGE_WRITABLE) &&
!pte_write(ptent) &&
can_change_pte_writable(vma, addr, ptent))
- ptent = pte_mkwrite(ptent);
+ ptent = pte_mkwrite(ptent, vma);
ptep_modify_prot_commit(vma, addr, pte, oldpte, ptent);
if (pte_needs_flush(oldpte, ptent))
diff --git a/mm/nommu.c b/mm/nommu.c
index 8dba41cfc44d..7f9e9e5a0e12 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1016,6 +1016,7 @@ unsigned long do_mmap(struct file *file,
unsigned long len,
unsigned long prot,
unsigned long flags,
+ vm_flags_t vm_flags,
unsigned long pgoff,
unsigned long *populate,
struct list_head *uf)
@@ -1023,7 +1024,6 @@ unsigned long do_mmap(struct file *file,
struct vm_area_struct *vma;
struct vm_region *region;
struct rb_node *rb;
- vm_flags_t vm_flags;
unsigned long capabilities, result;
int ret;
VMA_ITERATOR(vmi, current->mm, 0);
@@ -1043,7 +1043,7 @@ unsigned long do_mmap(struct file *file,
/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
- vm_flags = determine_vm_flags(file, prot, flags, capabilities);
+ vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
/* we're going to need to record the mapping */
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 0fc69efa4f1f..96d9eae5c7cc 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -86,7 +86,7 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd,
if (page_in_cache && !vm_shared)
writable = false;
if (writable)
- _dst_pte = pte_mkwrite(_dst_pte);
+ _dst_pte = pte_mkwrite(_dst_pte, dst_vma);
if (flags & MFILL_ATOMIC_WP)
_dst_pte = pte_mkuffd_wp(_dst_pte);
diff --git a/mm/util.c b/mm/util.c
index 4ed8b9b5273c..f08b655da917 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -543,7 +543,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
if (!ret) {
if (mmap_write_lock_killable(mm))
return -EINTR;
- ret = do_mmap(file, addr, len, prot, flag, pgoff, &populate,
+ ret = do_mmap(file, addr, len, prot, flag, 0, pgoff, &populate,
&uf);
mmap_write_unlock(mm);
userfaultfd_unmap_complete(mm, &uf);
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 598135d3162b..7e8c937627dd 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -18,7 +18,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
test_FCMOV test_FCOMI test_FISTTP \
vdso_restorer
TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \
- corrupt_xstate_header amx lam
+ corrupt_xstate_header amx lam test_shadow_stack
# Some selftests require 32bit support enabled also on 64bit systems
TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall
diff --git a/tools/testing/selftests/x86/test_shadow_stack.c b/tools/testing/selftests/x86/test_shadow_stack.c
new file mode 100644
index 000000000000..2188968674cb
--- /dev/null
+++ b/tools/testing/selftests/x86/test_shadow_stack.c
@@ -0,0 +1,884 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This program test's basic kernel shadow stack support. It enables shadow
+ * stack manual via the arch_prctl(), instead of relying on glibc. It's
+ * Makefile doesn't compile with shadow stack support, so it doesn't rely on
+ * any particular glibc. As a result it can't do any operations that require
+ * special glibc shadow stack support (longjmp(), swapcontext(), etc). Just
+ * stick to the basics and hope the compiler doesn't do anything strange.
+ */
+
+#define _GNU_SOURCE
+
+#include <sys/syscall.h>
+#include <asm/mman.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <x86intrin.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+#include <stdint.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/ioctl.h>
+#include <linux/userfaultfd.h>
+#include <setjmp.h>
+#include <sys/ptrace.h>
+#include <sys/signal.h>
+#include <linux/elf.h>
+
+/*
+ * Define the ABI defines if needed, so people can run the tests
+ * without building the headers.
+ */
+#ifndef __NR_map_shadow_stack
+#define __NR_map_shadow_stack 452
+
+#define SHADOW_STACK_SET_TOKEN (1ULL << 0)
+
+#define ARCH_SHSTK_ENABLE 0x5001
+#define ARCH_SHSTK_DISABLE 0x5002
+#define ARCH_SHSTK_LOCK 0x5003
+#define ARCH_SHSTK_UNLOCK 0x5004
+#define ARCH_SHSTK_STATUS 0x5005
+
+#define ARCH_SHSTK_SHSTK (1ULL << 0)
+#define ARCH_SHSTK_WRSS (1ULL << 1)
+
+#define NT_X86_SHSTK 0x204
+#endif
+
+#define SS_SIZE 0x200000
+#define PAGE_SIZE 0x1000
+
+#if (__GNUC__ < 8) || (__GNUC__ == 8 && __GNUC_MINOR__ < 5)
+int main(int argc, char *argv[])
+{
+ printf("[SKIP]\tCompiler does not support CET.\n");
+ return 0;
+}
+#else
+void write_shstk(unsigned long *addr, unsigned long val)
+{
+ asm volatile("wrssq %[val], (%[addr])\n"
+ : "=m" (addr)
+ : [addr] "r" (addr), [val] "r" (val));
+}
+
+static inline unsigned long __attribute__((always_inline)) get_ssp(void)
+{
+ unsigned long ret = 0;
+
+ asm volatile("xor %0, %0; rdsspq %0" : "=r" (ret));
+ return ret;
+}
+
+/*
+ * For use in inline enablement of shadow stack.
+ *
+ * The program can't return from the point where shadow stack gets enabled
+ * because there will be no address on the shadow stack. So it can't use
+ * syscall() for enablement, since it is a function.
+ *
+ * Based on code from nolibc.h. Keep a copy here because this can't pull in all
+ * of nolibc.h.
+ */
+#define ARCH_PRCTL(arg1, arg2) \
+({ \
+ long _ret; \
+ register long _num asm("eax") = __NR_arch_prctl; \
+ register long _arg1 asm("rdi") = (long)(arg1); \
+ register long _arg2 asm("rsi") = (long)(arg2); \
+ \
+ asm volatile ( \
+ "syscall\n" \
+ : "=a"(_ret) \
+ : "r"(_arg1), "r"(_arg2), \
+ "0"(_num) \
+ : "rcx", "r11", "memory", "cc" \
+ ); \
+ _ret; \
+})
+
+void *create_shstk(void *addr)
+{
+ return (void *)syscall(__NR_map_shadow_stack, addr, SS_SIZE, SHADOW_STACK_SET_TOKEN);
+}
+
+void *create_normal_mem(void *addr)
+{
+ return mmap(addr, SS_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+}
+
+void free_shstk(void *shstk)
+{
+ munmap(shstk, SS_SIZE);
+}
+
+int reset_shstk(void *shstk)
+{
+ return madvise(shstk, SS_SIZE, MADV_DONTNEED);
+}
+
+void try_shstk(unsigned long new_ssp)
+{
+ unsigned long ssp;
+
+ printf("[INFO]\tnew_ssp = %lx, *new_ssp = %lx\n",
+ new_ssp, *((unsigned long *)new_ssp));
+
+ ssp = get_ssp();
+ printf("[INFO]\tchanging ssp from %lx to %lx\n", ssp, new_ssp);
+
+ asm volatile("rstorssp (%0)\n":: "r" (new_ssp));
+ asm volatile("saveprevssp");
+ printf("[INFO]\tssp is now %lx\n", get_ssp());
+
+ /* Switch back to original shadow stack */
+ ssp -= 8;
+ asm volatile("rstorssp (%0)\n":: "r" (ssp));
+ asm volatile("saveprevssp");
+}
+
+int test_shstk_pivot(void)
+{
+ void *shstk = create_shstk(0);
+
+ if (shstk == MAP_FAILED) {
+ printf("[FAIL]\tError creating shadow stack: %d\n", errno);
+ return 1;
+ }
+ try_shstk((unsigned long)shstk + SS_SIZE - 8);
+ free_shstk(shstk);
+
+ printf("[OK]\tShadow stack pivot\n");
+ return 0;
+}
+
+int test_shstk_faults(void)
+{
+ unsigned long *shstk = create_shstk(0);
+
+ /* Read shadow stack, test if it's zero to not get read optimized out */
+ if (*shstk != 0)
+ goto err;
+
+ /* Wrss memory that was already read. */
+ write_shstk(shstk, 1);
+ if (*shstk != 1)
+ goto err;
+
+ /* Page out memory, so we can wrss it again. */
+ if (reset_shstk((void *)shstk))
+ goto err;
+
+ write_shstk(shstk, 1);
+ if (*shstk != 1)
+ goto err;
+
+ printf("[OK]\tShadow stack faults\n");
+ return 0;
+
+err:
+ return 1;
+}
+
+unsigned long saved_ssp;
+unsigned long saved_ssp_val;
+volatile bool segv_triggered;
+
+void __attribute__((noinline)) violate_ss(void)
+{
+ saved_ssp = get_ssp();
+ saved_ssp_val = *(unsigned long *)saved_ssp;
+
+ /* Corrupt shadow stack */
+ printf("[INFO]\tCorrupting shadow stack\n");
+ write_shstk((void *)saved_ssp, 0);
+}
+
+void segv_handler(int signum, siginfo_t *si, void *uc)
+{
+ printf("[INFO]\tGenerated shadow stack violation successfully\n");
+
+ segv_triggered = true;
+
+ /* Fix shadow stack */
+ write_shstk((void *)saved_ssp, saved_ssp_val);
+}
+
+int test_shstk_violation(void)
+{
+ struct sigaction sa = {};
+
+ sa.sa_sigaction = segv_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ segv_triggered = false;
+
+ /* Make sure segv_triggered is set before violate_ss() */
+ asm volatile("" : : : "memory");
+
+ violate_ss();
+
+ signal(SIGSEGV, SIG_DFL);
+
+ printf("[OK]\tShadow stack violation test\n");
+
+ return !segv_triggered;
+}
+
+/* Gup test state */
+#define MAGIC_VAL 0x12345678
+bool is_shstk_access;
+void *shstk_ptr;
+int fd;
+
+void reset_test_shstk(void *addr)
+{
+ if (shstk_ptr)
+ free_shstk(shstk_ptr);
+ shstk_ptr = create_shstk(addr);
+}
+
+void test_access_fix_handler(int signum, siginfo_t *si, void *uc)
+{
+ printf("[INFO]\tViolation from %s\n", is_shstk_access ? "shstk access" : "normal write");
+
+ segv_triggered = true;
+
+ /* Fix shadow stack */
+ if (is_shstk_access) {
+ reset_test_shstk(shstk_ptr);
+ return;
+ }
+
+ free_shstk(shstk_ptr);
+ create_normal_mem(shstk_ptr);
+}
+
+bool test_shstk_access(void *ptr)
+{
+ is_shstk_access = true;
+ segv_triggered = false;
+ write_shstk(ptr, MAGIC_VAL);
+
+ asm volatile("" : : : "memory");
+
+ return segv_triggered;
+}
+
+bool test_write_access(void *ptr)
+{
+ is_shstk_access = false;
+ segv_triggered = false;
+ *(unsigned long *)ptr = MAGIC_VAL;
+
+ asm volatile("" : : : "memory");
+
+ return segv_triggered;
+}
+
+bool gup_write(void *ptr)
+{
+ unsigned long val;
+
+ lseek(fd, (unsigned long)ptr, SEEK_SET);
+ if (write(fd, &val, sizeof(val)) < 0)
+ return 1;
+
+ return 0;
+}
+
+bool gup_read(void *ptr)
+{
+ unsigned long val;
+
+ lseek(fd, (unsigned long)ptr, SEEK_SET);
+ if (read(fd, &val, sizeof(val)) < 0)
+ return 1;
+
+ return 0;
+}
+
+int test_gup(void)
+{
+ struct sigaction sa = {};
+ int status;
+ pid_t pid;
+
+ sa.sa_sigaction = test_access_fix_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ segv_triggered = false;
+
+ fd = open("/proc/self/mem", O_RDWR);
+ if (fd == -1)
+ return 1;
+
+ reset_test_shstk(0);
+ if (gup_read(shstk_ptr))
+ return 1;
+ if (test_shstk_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup read -> shstk access success\n");
+
+ reset_test_shstk(0);
+ if (gup_write(shstk_ptr))
+ return 1;
+ if (test_shstk_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup write -> shstk access success\n");
+
+ reset_test_shstk(0);
+ if (gup_read(shstk_ptr))
+ return 1;
+ if (!test_write_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup read -> write access success\n");
+
+ reset_test_shstk(0);
+ if (gup_write(shstk_ptr))
+ return 1;
+ if (!test_write_access(shstk_ptr))
+ return 1;
+ printf("[INFO]\tGup write -> write access success\n");
+
+ close(fd);
+
+ /* COW/gup test */
+ reset_test_shstk(0);
+ pid = fork();
+ if (!pid) {
+ fd = open("/proc/self/mem", O_RDWR);
+ if (fd == -1)
+ exit(1);
+
+ if (gup_write(shstk_ptr)) {
+ close(fd);
+ exit(1);
+ }
+ close(fd);
+ exit(0);
+ }
+ waitpid(pid, &status, 0);
+ if (WEXITSTATUS(status)) {
+ printf("[FAIL]\tWrite in child failed\n");
+ return 1;
+ }
+ if (*(unsigned long *)shstk_ptr == MAGIC_VAL) {
+ printf("[FAIL]\tWrite in child wrote through to shared memory\n");
+ return 1;
+ }
+
+ printf("[INFO]\tCow gup write -> write access success\n");
+
+ free_shstk(shstk_ptr);
+
+ signal(SIGSEGV, SIG_DFL);
+
+ printf("[OK]\tShadow gup test\n");
+
+ return 0;
+}
+
+int test_mprotect(void)
+{
+ struct sigaction sa = {};
+
+ sa.sa_sigaction = test_access_fix_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ segv_triggered = false;
+
+ /* mprotect a shadow stack as read only */
+ reset_test_shstk(0);
+ if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
+ printf("[FAIL]\tmprotect(PROT_READ) failed\n");
+ return 1;
+ }
+
+ /* try to wrss it and fail */
+ if (!test_shstk_access(shstk_ptr)) {
+ printf("[FAIL]\tShadow stack access to read-only memory succeeded\n");
+ return 1;
+ }
+
+ /*
+ * The shadow stack was reset above to resolve the fault, make the new one
+ * read-only.
+ */
+ if (mprotect(shstk_ptr, SS_SIZE, PROT_READ) < 0) {
+ printf("[FAIL]\tmprotect(PROT_READ) failed\n");
+ return 1;
+ }
+
+ /* then back to writable */
+ if (mprotect(shstk_ptr, SS_SIZE, PROT_WRITE | PROT_READ) < 0) {
+ printf("[FAIL]\tmprotect(PROT_WRITE) failed\n");
+ return 1;
+ }
+
+ /* then wrss to it and succeed */
+ if (test_shstk_access(shstk_ptr)) {
+ printf("[FAIL]\tShadow stack access to mprotect() writable memory failed\n");
+ return 1;
+ }
+
+ free_shstk(shstk_ptr);
+
+ signal(SIGSEGV, SIG_DFL);
+
+ printf("[OK]\tmprotect() test\n");
+
+ return 0;
+}
+
+char zero[4096];
+
+static void *uffd_thread(void *arg)
+{
+ struct uffdio_copy req;
+ int uffd = *(int *)arg;
+ struct uffd_msg msg;
+ int ret;
+
+ while (1) {
+ ret = read(uffd, &msg, sizeof(msg));
+ if (ret > 0)
+ break;
+ else if (errno == EAGAIN)
+ continue;
+ return (void *)1;
+ }
+
+ req.dst = msg.arg.pagefault.address;
+ req.src = (__u64)zero;
+ req.len = 4096;
+ req.mode = 0;
+
+ if (ioctl(uffd, UFFDIO_COPY, &req))
+ return (void *)1;
+
+ return (void *)0;
+}
+
+int test_userfaultfd(void)
+{
+ struct uffdio_register uffdio_register;
+ struct uffdio_api uffdio_api;
+ struct sigaction sa = {};
+ pthread_t thread;
+ void *res;
+ int uffd;
+
+ sa.sa_sigaction = test_access_fix_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+ if (uffd < 0) {
+ printf("[SKIP]\tUserfaultfd unavailable.\n");
+ return 0;
+ }
+
+ reset_test_shstk(0);
+
+ uffdio_api.api = UFFD_API;
+ uffdio_api.features = 0;
+ if (ioctl(uffd, UFFDIO_API, &uffdio_api))
+ goto err;
+
+ uffdio_register.range.start = (__u64)shstk_ptr;
+ uffdio_register.range.len = 4096;
+ uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
+ goto err;
+
+ if (pthread_create(&thread, NULL, &uffd_thread, &uffd))
+ goto err;
+
+ reset_shstk(shstk_ptr);
+ test_shstk_access(shstk_ptr);
+
+ if (pthread_join(thread, &res))
+ goto err;
+
+ if (test_shstk_access(shstk_ptr))
+ goto err;
+
+ free_shstk(shstk_ptr);
+
+ signal(SIGSEGV, SIG_DFL);
+
+ if (!res)
+ printf("[OK]\tUserfaultfd test\n");
+ return !!res;
+err:
+ free_shstk(shstk_ptr);
+ close(uffd);
+ signal(SIGSEGV, SIG_DFL);
+ return 1;
+}
+
+/* Simple linked list for keeping track of mappings in test_guard_gap() */
+struct node {
+ struct node *next;
+ void *mapping;
+};
+
+/*
+ * This tests whether mmap will place other mappings in a shadow stack's guard
+ * gap. The steps are:
+ * 1. Finds an empty place by mapping and unmapping something.
+ * 2. Map a shadow stack in the middle of the known empty area.
+ * 3. Map a bunch of PAGE_SIZE mappings. These will use the search down
+ * direction, filling any gaps until it encounters the shadow stack's
+ * guard gap.
+ * 4. When a mapping lands below the shadow stack from step 2, then all
+ * of the above gaps are filled. The search down algorithm will have
+ * looked at the shadow stack gaps.
+ * 5. See if it landed in the gap.
+ */
+int test_guard_gap(void)
+{
+ void *free_area, *shstk, *test_map = (void *)0xFFFFFFFFFFFFFFFF;
+ struct node *head = NULL, *cur;
+
+ free_area = mmap(0, SS_SIZE * 3, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ munmap(free_area, SS_SIZE * 3);
+
+ shstk = create_shstk(free_area + SS_SIZE);
+ if (shstk == MAP_FAILED)
+ return 1;
+
+ while (test_map > shstk) {
+ test_map = mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (test_map == MAP_FAILED)
+ return 1;
+ cur = malloc(sizeof(*cur));
+ cur->mapping = test_map;
+
+ cur->next = head;
+ head = cur;
+ }
+
+ while (head) {
+ cur = head;
+ head = cur->next;
+ munmap(cur->mapping, PAGE_SIZE);
+ free(cur);
+ }
+
+ free_shstk(shstk);
+
+ if (shstk - test_map - PAGE_SIZE != PAGE_SIZE)
+ return 1;
+
+ printf("[OK]\tGuard gap test\n");
+
+ return 0;
+}
+
+/*
+ * Too complicated to pull it out of the 32 bit header, but also get the
+ * 64 bit one needed above. Just define a copy here.
+ */
+#define __NR_compat_sigaction 67
+
+/*
+ * Call 32 bit signal handler to get 32 bit signals ABI. Make sure
+ * to push the registers that will get clobbered.
+ */
+int sigaction32(int signum, const struct sigaction *restrict act,
+ struct sigaction *restrict oldact)
+{
+ register long syscall_reg asm("eax") = __NR_compat_sigaction;
+ register long signum_reg asm("ebx") = signum;
+ register long act_reg asm("ecx") = (long)act;
+ register long oldact_reg asm("edx") = (long)oldact;
+ int ret = 0;
+
+ asm volatile ("int $0x80;"
+ : "=a"(ret), "=m"(oldact)
+ : "r"(syscall_reg), "r"(signum_reg), "r"(act_reg),
+ "r"(oldact_reg)
+ : "r8", "r9", "r10", "r11"
+ );
+
+ return ret;
+}
+
+sigjmp_buf jmp_buffer;
+
+void segv_gp_handler(int signum, siginfo_t *si, void *uc)
+{
+ segv_triggered = true;
+
+ /*
+ * To work with old glibc, this can't rely on siglongjmp working with
+ * shadow stack enabled, so disable shadow stack before siglongjmp().
+ */
+ ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
+ siglongjmp(jmp_buffer, -1);
+}
+
+/*
+ * Transition to 32 bit mode and check that a #GP triggers a segfault.
+ */
+int test_32bit(void)
+{
+ struct sigaction sa = {};
+ struct sigaction *sa32;
+
+ /* Create sigaction in 32 bit address range */
+ sa32 = mmap(0, 4096, PROT_READ | PROT_WRITE,
+ MAP_32BIT | MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+ sa32->sa_flags = SA_SIGINFO;
+
+ sa.sa_sigaction = segv_gp_handler;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+
+ segv_triggered = false;
+
+ /* Make sure segv_triggered is set before triggering the #GP */
+ asm volatile("" : : : "memory");
+
+ /*
+ * Set handler to somewhere in 32 bit address space
+ */
+ sa32->sa_handler = (void *)sa32;
+ if (sigaction32(SIGUSR1, sa32, NULL))
+ return 1;
+
+ if (!sigsetjmp(jmp_buffer, 1))
+ raise(SIGUSR1);
+
+ if (segv_triggered)
+ printf("[OK]\t32 bit test\n");
+
+ return !segv_triggered;
+}
+
+void segv_handler_ptrace(int signum, siginfo_t *si, void *uc)
+{
+ /* The SSP adjustment caused a segfault. */
+ exit(0);
+}
+
+int test_ptrace(void)
+{
+ unsigned long saved_ssp, ssp = 0;
+ struct sigaction sa= {};
+ struct iovec iov;
+ int status;
+ int pid;
+
+ iov.iov_base = &ssp;
+ iov.iov_len = sizeof(ssp);
+
+ pid = fork();
+ if (!pid) {
+ ssp = get_ssp();
+
+ sa.sa_sigaction = segv_handler_ptrace;
+ sa.sa_flags = SA_SIGINFO;
+ if (sigaction(SIGSEGV, &sa, NULL))
+ return 1;
+
+ ptrace(PTRACE_TRACEME, NULL, NULL, NULL);
+ /*
+ * The parent will tweak the SSP and return from this function
+ * will #CP.
+ */
+ raise(SIGTRAP);
+
+ exit(1);
+ }
+
+ while (waitpid(pid, &status, 0) != -1 && WSTOPSIG(status) != SIGTRAP);
+
+ if (ptrace(PTRACE_GETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tFailed to PTRACE_GETREGS\n");
+ goto out_kill;
+ }
+
+ if (!ssp) {
+ printf("[INFO]\tPtrace child SSP was 0\n");
+ goto out_kill;
+ }
+
+ saved_ssp = ssp;
+
+ iov.iov_len = 0;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tToo small size accepted via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ iov.iov_len = sizeof(ssp) + 1;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tToo large size accepted via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ ssp += 1;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tUnaligned SSP written via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ ssp = 0xFFFFFFFFFFFF0000;
+ if (!ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tKernel range SSP written via PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ /*
+ * Tweak the SSP so the child with #CP when it resumes and returns
+ * from raise()
+ */
+ ssp = saved_ssp + 8;
+ iov.iov_len = sizeof(ssp);
+ if (ptrace(PTRACE_SETREGSET, pid, NT_X86_SHSTK, &iov)) {
+ printf("[INFO]\tFailed to PTRACE_SETREGS\n");
+ goto out_kill;
+ }
+
+ if (ptrace(PTRACE_DETACH, pid, NULL, NULL)) {
+ printf("[INFO]\tFailed to PTRACE_DETACH\n");
+ goto out_kill;
+ }
+
+ waitpid(pid, &status, 0);
+ if (WEXITSTATUS(status))
+ return 1;
+
+ printf("[OK]\tPtrace test\n");
+ return 0;
+
+out_kill:
+ kill(pid, SIGKILL);
+ return 1;
+}
+
+int main(int argc, char *argv[])
+{
+ int ret = 0;
+
+ if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
+ printf("[SKIP]\tCould not enable Shadow stack\n");
+ return 1;
+ }
+
+ if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK)) {
+ ret = 1;
+ printf("[FAIL]\tDisabling shadow stack failed\n");
+ }
+
+ if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK)) {
+ printf("[SKIP]\tCould not re-enable Shadow stack\n");
+ return 1;
+ }
+
+ if (ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_WRSS)) {
+ printf("[SKIP]\tCould not enable WRSS\n");
+ ret = 1;
+ goto out;
+ }
+
+ /* Should have succeeded if here, but this is a test, so double check. */
+ if (!get_ssp()) {
+ printf("[FAIL]\tShadow stack disabled\n");
+ return 1;
+ }
+
+ if (test_shstk_pivot()) {
+ ret = 1;
+ printf("[FAIL]\tShadow stack pivot\n");
+ goto out;
+ }
+
+ if (test_shstk_faults()) {
+ ret = 1;
+ printf("[FAIL]\tShadow stack fault test\n");
+ goto out;
+ }
+
+ if (test_shstk_violation()) {
+ ret = 1;
+ printf("[FAIL]\tShadow stack violation test\n");
+ goto out;
+ }
+
+ if (test_gup()) {
+ ret = 1;
+ printf("[FAIL]\tShadow shadow stack gup\n");
+ goto out;
+ }
+
+ if (test_mprotect()) {
+ ret = 1;
+ printf("[FAIL]\tShadow shadow mprotect test\n");
+ goto out;
+ }
+
+ if (test_userfaultfd()) {
+ ret = 1;
+ printf("[FAIL]\tUserfaultfd test\n");
+ goto out;
+ }
+
+ if (test_guard_gap()) {
+ ret = 1;
+ printf("[FAIL]\tGuard gap test\n");
+ goto out;
+ }
+
+ if (test_ptrace()) {
+ ret = 1;
+ printf("[FAIL]\tptrace test\n");
+ }
+
+ if (test_32bit()) {
+ ret = 1;
+ printf("[FAIL]\t32 bit test\n");
+ goto out;
+ }
+
+ return ret;
+
+out:
+ /*
+ * Disable shadow stack before the function returns, or there will be a
+ * shadow stack violation.
+ */
+ if (ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK)) {
+ ret = 1;
+ printf("[FAIL]\tDisabling shadow stack failed\n");
+ }
+
+ return ret;
+}
+#endif