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-rw-r--r--arch/x86/entry/common.c3
-rw-r--r--arch/x86/entry/entry_64_compat.S2
-rw-r--r--arch/x86/include/asm/insn-eval.h2
-rw-r--r--arch/x86/include/asm/proto.h1
-rw-r--r--arch/x86/include/asm/ptrace.h15
-rw-r--r--arch/x86/kernel/sev-es.c22
-rw-r--r--arch/x86/kernel/traps.c3
-rw-r--r--arch/x86/kernel/unwind_orc.c14
-rw-r--r--arch/x86/lib/insn-eval.c66
9 files changed, 99 insertions, 29 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index a2433ae8a65e..4efd39aacb9f 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -128,7 +128,8 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
regs->ax = -EFAULT;
instrumentation_end();
- syscall_exit_to_user_mode(regs);
+ local_irq_disable();
+ irqentry_exit_to_user_mode(regs);
return false;
}
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 541fdaf64045..0051cf5c792d 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -210,6 +210,8 @@ SYM_CODE_START(entry_SYSCALL_compat)
/* Switch to the kernel stack */
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL)
+
/* Construct struct pt_regs on stack */
pushq $__USER32_DS /* pt_regs->ss */
pushq %r8 /* pt_regs->sp */
diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index a0f839aa144d..98b4dae5e8bc 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h
@@ -23,6 +23,8 @@ unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx);
int insn_get_code_seg_params(struct pt_regs *regs);
int insn_fetch_from_user(struct pt_regs *regs,
unsigned char buf[MAX_INSN_SIZE]);
+int insn_fetch_from_user_inatomic(struct pt_regs *regs,
+ unsigned char buf[MAX_INSN_SIZE]);
bool insn_decode(struct insn *insn, struct pt_regs *regs,
unsigned char buf[MAX_INSN_SIZE], int buf_size);
diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index 2c35f1c01a2d..b6a9d51d1d79 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -25,6 +25,7 @@ void __end_SYSENTER_singlestep_region(void);
void entry_SYSENTER_compat(void);
void __end_entry_SYSENTER_compat(void);
void entry_SYSCALL_compat(void);
+void entry_SYSCALL_compat_safe_stack(void);
void entry_INT80_compat(void);
#ifdef CONFIG_XEN_PV
void xen_entry_INT80_compat(void);
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index d8324a236696..409f661481e1 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -94,6 +94,8 @@ struct pt_regs {
#include <asm/paravirt_types.h>
#endif
+#include <asm/proto.h>
+
struct cpuinfo_x86;
struct task_struct;
@@ -175,6 +177,19 @@ static inline bool any_64bit_mode(struct pt_regs *regs)
#ifdef CONFIG_X86_64
#define current_user_stack_pointer() current_pt_regs()->sp
#define compat_user_stack_pointer() current_pt_regs()->sp
+
+static inline bool ip_within_syscall_gap(struct pt_regs *regs)
+{
+ bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
+ regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack);
+
+#ifdef CONFIG_IA32_EMULATION
+ ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat &&
+ regs->ip < (unsigned long)entry_SYSCALL_compat_safe_stack);
+#endif
+
+ return ret;
+}
#endif
static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 84c1821819af..04a780abb512 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -121,8 +121,18 @@ static void __init setup_vc_stacks(int cpu)
cea_set_pte((void *)vaddr, pa, PAGE_KERNEL);
}
-static __always_inline bool on_vc_stack(unsigned long sp)
+static __always_inline bool on_vc_stack(struct pt_regs *regs)
{
+ unsigned long sp = regs->sp;
+
+ /* User-mode RSP is not trusted */
+ if (user_mode(regs))
+ return false;
+
+ /* SYSCALL gap still has user-mode RSP */
+ if (ip_within_syscall_gap(regs))
+ return false;
+
return ((sp >= __this_cpu_ist_bottom_va(VC)) && (sp < __this_cpu_ist_top_va(VC)));
}
@@ -144,7 +154,7 @@ void noinstr __sev_es_ist_enter(struct pt_regs *regs)
old_ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]);
/* Make room on the IST stack */
- if (on_vc_stack(regs->sp))
+ if (on_vc_stack(regs))
new_ist = ALIGN_DOWN(regs->sp, 8) - sizeof(old_ist);
else
new_ist = old_ist - sizeof(old_ist);
@@ -248,7 +258,7 @@ static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
int res;
if (user_mode(ctxt->regs)) {
- res = insn_fetch_from_user(ctxt->regs, buffer);
+ res = insn_fetch_from_user_inatomic(ctxt->regs, buffer);
if (!res) {
ctxt->fi.vector = X86_TRAP_PF;
ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER;
@@ -1248,13 +1258,12 @@ static __always_inline bool on_vc_fallback_stack(struct pt_regs *regs)
DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
{
struct sev_es_runtime_data *data = this_cpu_read(runtime_data);
+ irqentry_state_t irq_state;
struct ghcb_state state;
struct es_em_ctxt ctxt;
enum es_result result;
struct ghcb *ghcb;
- lockdep_assert_irqs_disabled();
-
/*
* Handle #DB before calling into !noinstr code to avoid recursive #DB.
*/
@@ -1263,6 +1272,8 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
return;
}
+ irq_state = irqentry_nmi_enter(regs);
+ lockdep_assert_irqs_disabled();
instrumentation_begin();
/*
@@ -1325,6 +1336,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
out:
instrumentation_end();
+ irqentry_nmi_exit(regs, irq_state);
return;
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 7f5aec758f0e..ac1874a2a70e 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -694,8 +694,7 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r
* In the SYSCALL entry path the RSP value comes from user-space - don't
* trust it and switch to the current kernel stack
*/
- if (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
- regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack) {
+ if (ip_within_syscall_gap(regs)) {
sp = this_cpu_read(cpu_current_top_of_stack);
goto sync;
}
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 2a1d47f47eee..a1202536fc57 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -13,7 +13,7 @@
#define orc_warn_current(args...) \
({ \
- if (state->task == current) \
+ if (state->task == current && !state->error) \
orc_warn(args); \
})
@@ -367,8 +367,8 @@ static bool deref_stack_regs(struct unwind_state *state, unsigned long addr,
if (!stack_access_ok(state, addr, sizeof(struct pt_regs)))
return false;
- *ip = regs->ip;
- *sp = regs->sp;
+ *ip = READ_ONCE_NOCHECK(regs->ip);
+ *sp = READ_ONCE_NOCHECK(regs->sp);
return true;
}
@@ -380,8 +380,8 @@ static bool deref_stack_iret_regs(struct unwind_state *state, unsigned long addr
if (!stack_access_ok(state, addr, IRET_FRAME_SIZE))
return false;
- *ip = regs->ip;
- *sp = regs->sp;
+ *ip = READ_ONCE_NOCHECK(regs->ip);
+ *sp = READ_ONCE_NOCHECK(regs->sp);
return true;
}
@@ -402,12 +402,12 @@ static bool get_reg(struct unwind_state *state, unsigned int reg_off,
return false;
if (state->full_regs) {
- *val = ((unsigned long *)state->regs)[reg];
+ *val = READ_ONCE_NOCHECK(((unsigned long *)state->regs)[reg]);
return true;
}
if (state->prev_regs) {
- *val = ((unsigned long *)state->prev_regs)[reg];
+ *val = READ_ONCE_NOCHECK(((unsigned long *)state->prev_regs)[reg]);
return true;
}
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 4229950a5d78..bb0b3fe1e0a0 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -1415,6 +1415,25 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
}
}
+static unsigned long insn_get_effective_ip(struct pt_regs *regs)
+{
+ unsigned long seg_base = 0;
+
+ /*
+ * If not in user-space long mode, a custom code segment could be in
+ * use. This is true in protected mode (if the process defined a local
+ * descriptor table), or virtual-8086 mode. In most of the cases
+ * seg_base will be zero as in USER_CS.
+ */
+ if (!user_64bit_mode(regs)) {
+ seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS);
+ if (seg_base == -1L)
+ return 0;
+ }
+
+ return seg_base + regs->ip;
+}
+
/**
* insn_fetch_from_user() - Copy instruction bytes from user-space memory
* @regs: Structure with register values as seen when entering kernel mode
@@ -1431,24 +1450,43 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
*/
int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE])
{
- unsigned long seg_base = 0;
+ unsigned long ip;
int not_copied;
- /*
- * If not in user-space long mode, a custom code segment could be in
- * use. This is true in protected mode (if the process defined a local
- * descriptor table), or virtual-8086 mode. In most of the cases
- * seg_base will be zero as in USER_CS.
- */
- if (!user_64bit_mode(regs)) {
- seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS);
- if (seg_base == -1L)
- return 0;
- }
+ ip = insn_get_effective_ip(regs);
+ if (!ip)
+ return 0;
+
+ not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE);
+ return MAX_INSN_SIZE - not_copied;
+}
+
+/**
+ * insn_fetch_from_user_inatomic() - Copy instruction bytes from user-space memory
+ * while in atomic code
+ * @regs: Structure with register values as seen when entering kernel mode
+ * @buf: Array to store the fetched instruction
+ *
+ * Gets the linear address of the instruction and copies the instruction bytes
+ * to the buf. This function must be used in atomic context.
+ *
+ * Returns:
+ *
+ * Number of instruction bytes copied.
+ *
+ * 0 if nothing was copied.
+ */
+int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE])
+{
+ unsigned long ip;
+ int not_copied;
+
+ ip = insn_get_effective_ip(regs);
+ if (!ip)
+ return 0;
- not_copied = copy_from_user(buf, (void __user *)(seg_base + regs->ip),
- MAX_INSN_SIZE);
+ not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE);
return MAX_INSN_SIZE - not_copied;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-28 19:16:26 +0000