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* ARM: 9326/1: make <linux/uaccess.h> self-contained for ARMMasahiro Yamada2023-10-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I compiled the following code for ARM, I encountered numerous errors. [Test Code] #include <linux/compiler.h> #include <linux/uaccess.h> int foo(int *x, int __user *ptr) { return get_user(*x, ptr); } To fix the errors, make some asm headers self-contained: 1. In arch/arm/include/asm/domain.h, include <linux/thread_info.h> for current_thread_info(). 2. In arch/arm/include/asm/traps.h, remove unneeded __init, and include <linux/linkage.h> for asmlinkage. 3. In arch/arm/include/asm/uaccess.h, include <linux/kernel.h> for might_fault(). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9324/1: fix get_user() broken with veneerMasahiro Yamada2023-10-051-12/+2
| | | | | | | | | | | | | | | | | | | | | | | The 32-bit ARM kernel stops working if the kernel grows to the point where veneers for __get_user_* are created. AAPCS32 [1] states, "Register r12 (IP) may be used by a linker as a scratch register between a routine and any subroutine it calls. It can also be used within a routine to hold intermediate values between subroutine calls." However, bl instructions buried within the inline asm are unpredictable for compilers; hence, "ip" must be added to the clobber list. This becomes critical when veneers for __get_user_* are created because veneers use the ip register since commit 02e541db0540 ("ARM: 8323/1: force linker to use PIC veneers"). [1]: https://github.com/ARM-software/abi-aa/blob/2023Q1/aapcs32/aapcs32.rst Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: mm: Make virt_to_pfn() a static inlineLinus Walleij2023-05-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Making virt_to_pfn() a static inline taking a strongly typed (const void *) makes the contract of a passing a pointer of that type to the function explicit and exposes any misuse of the macro virt_to_pfn() acting polymorphic and accepting many types such as (void *), (unitptr_t) or (unsigned long) as arguments without warnings. Doing this is a bit intrusive: virt_to_pfn() requires PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in <asm/page.h>, so this must be included *before* <asm/memory.h>. The use of macros were obscuring the unclear inclusion order here, as the macros would eventually be resolved, but a static inline like this cannot be compiled with unresolved macros. The naive solution to include <asm/page.h> at the top of <asm/memory.h> does not work, because <asm/memory.h> sometimes includes <asm/page.h> at the end of itself, which would create a confusing inclusion loop. So instead, take the approach to always unconditionally include <asm/page.h> at the end of <asm/memory.h> arch/arm uses <asm/memory.h> explicitly in a lot of places, however it turns out that if we just unconditionally include <asm/memory.h> into <asm/page.h> and switch all inclusions of <asm/memory.h> to <asm/page.h> instead, we enforce the right order and <asm/memory.h> will always have access to the definitions. Put an inclusion guard in place making it impossible to include <asm/memory.h> explicitly. Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/ Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
* uaccess: generalize access_ok()Arnd Bergmann2022-02-251-19/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* uaccess: add generic __{get,put}_kernel_nofaultArnd Bergmann2022-02-251-2/+0
| | | | | | | | | | | | | Nine architectures are still missing __{get,put}_kernel_nofault: alpha, ia64, microblaze, nds32, nios2, openrisc, sh, sparc32, xtensa. Add a generic version that lets everything use the normal copy_{from,to}_kernel_nofault() code based on these, removing the last use of get_fs()/set_fs() from architecture-independent code. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* ARM: 9179/1: uaccess: avoid alignment faults in copy_[from|to]_kernel_nofaultArd Biesheuvel2022-01-191-2/+8
| | | | | | | | | | | | | | | | | | | | | The helpers that are used to implement copy_from_kernel_nofault() and copy_to_kernel_nofault() cast a void* to a pointer to a wider type, which may result in alignment faults on ARM if the compiler decides to use double-word or multiple-word load/store instructions. Only configurations that define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y are affected, given that commit 2423de2e6f4d ("ARM: 9115/1: mm/maccess: fix unaligned copy_{from,to}_kernel_nofault") ensures that dst and src are sufficiently aligned otherwise. So use the unaligned accessors for accessing dst and src in cases where they may be misaligned. Cc: <stable@vger.kernel.org> # depends on 2423de2e6f4d Fixes: 2df4c9a741a0 ("ARM: 9112/1: uaccess: add __{get,put}_kernel_nofault") Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9132/1: Fix __get_user_check failure with ARM KASAN imagesLexi Shao2021-10-191-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ARM: kasan: Fix __get_user_check failure with kasan In macro __get_user_check defined in arch/arm/include/asm/uaccess.h, error code is store in register int __e(r0). When kasan is enabled, assigning value to kernel address might trigger kasan check, which unexpectedly overwrites r0 and causes undefined behavior on arm kasan images. One example is failure in do_futex and results in process soft lockup. Log: watchdog: BUG: soft lockup - CPU#0 stuck for 62946ms! [rs:main Q:Reg:1151] ... (__asan_store4) from (futex_wait_setup+0xf8/0x2b4) (futex_wait_setup) from (futex_wait+0x138/0x394) (futex_wait) from (do_futex+0x164/0xe40) (do_futex) from (sys_futex_time32+0x178/0x230) (sys_futex_time32) from (ret_fast_syscall+0x0/0x50) The soft lockup happens in function futex_wait_setup. The reason is function get_futex_value_locked always return EINVAL, thus pc jump back to retry label and causes looping. This line in function get_futex_value_locked ret = __get_user(*dest, from); is expanded to *dest = (typeof(*(p))) __r2; , in macro __get_user_check. Writing to pointer dest triggers kasan check and overwrites the return value of __get_user_x function. The assembly code of get_futex_value_locked in kernel/futex.c: ... c01f6dc8: eb0b020e bl c04b7608 <__get_user_4> // "x = (typeof(*(p))) __r2;" triggers kasan check and r0 is overwritten c01f6dCc: e1a00007 mov r0, r7 c01f6dd0: e1a05002 mov r5, r2 c01f6dd4: eb04f1e6 bl c0333574 <__asan_store4> c01f6dd8: e5875000 str r5, [r7] // save ret value of __get_user(*dest, from), which is dest address now c01f6ddc: e1a05000 mov r5, r0 ... // checking return value of __get_user failed c01f6e00: e3550000 cmp r5, #0 ... c01f6e0c: 01a00005 moveq r0, r5 // assign return value to EINVAL c01f6e10: 13e0000d mvnne r0, #13 Return value is the destination address of get_user thus certainly non-zero, so get_futex_value_locked always return EINVAL. Fix it by using a tmp vairable to store the error code before the assignment. This fix has no effects to non-kasan images thanks to compiler optimization. It only affects cases that overwrite r0 due to kasan check. This should fix bug discussed in Link: [1] https://lore.kernel.org/linux-arm-kernel/0ef7c2a5-5d8b-c5e0-63fa-31693fd4495c@gmail.com/ Fixes: 421015713b30 ("ARM: 9017/2: Enable KASan for ARM") Signed-off-by: Lexi Shao <shaolexi@huawei.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9113/1: uaccess: remove set_fs() implementationArnd Bergmann2021-08-201-42/+4
| | | | | | | | | | | | | | | | | | | | There are no remaining callers of set_fs(), so just remove it along with all associated code that operates on thread_info->addr_limit. There are still further optimizations that can be done: - In get_user(), the address check could be moved entirely into the out of line code, rather than passing a constant as an argument, - I assume the DACR handling can be simplified as we now only change it during user access when CONFIG_CPU_SW_DOMAIN_PAN is set, but not during set_fs(). Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9112/1: uaccess: add __{get,put}_kernel_nofaultArnd Bergmann2021-08-201-40/+83
| | | | | | | | | | | | | | | | | | | These mimic the behavior of get_user and put_user, except for domain switching, address limit checking and handling of mismatched sizes, none of which are relevant here. To work with pre-Armv6 kernels, this has to avoid TUSER() inside of the new macros, the new approach passes the "t" string along with the opcode, which is a bit uglier but avoids duplicating more code. As there is no __get_user_asm_dword(), I work around it by copying 32 bit at a time, which is possible because the output size is known. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* uaccess: remove segment_eqChristoph Hellwig2020-08-121-2/+2
| | | | | | | | | | | | | | | | | | segment_eq is only used to implement uaccess_kernel. Just open code uaccess_kernel in the arch uaccess headers and remove one layer of indirection. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Greentime Hu <green.hu@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ARM: uaccess: add further explanation of __range_ok()Russell King2020-07-221-1/+5
| | | | | | | Detail the success return condition, and that we rely on KERNEL_DS being zero for this to operate correctly. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* ARM: 8908/1: add __always_inline to functions called from __get_user_check()Masahiro Yamada2019-10-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | KernelCI reports that bcm2835_defconfig is no longer booting since commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") (https://lkml.org/lkml/2019/9/26/825). I also received a regression report from Nicolas Saenz Julienne (https://lkml.org/lkml/2019/9/27/263). This problem has cropped up on bcm2835_defconfig because it enables CONFIG_CC_OPTIMIZE_FOR_SIZE. The compiler tends to prefer not inlining functions with -Os. I was able to reproduce it with other boards and defconfig files by manually enabling CONFIG_CC_OPTIMIZE_FOR_SIZE. The __get_user_check() specifically uses r0, r1, r2 registers. So, uaccess_save_and_enable() and uaccess_restore() must be inlined. Otherwise, those register assignments would be entirely dropped, according to my analysis of the disassembly. Prior to commit 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING"), the 'inline' marker was always enough for inlining functions, except on x86. Since that commit, all architectures can enable CONFIG_OPTIMIZE_INLINING. So, __always_inline is now the only guaranteed way of forcible inlining. I added __always_inline to 4 functions in the call-graph from the __get_user_check() macro. Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING") Reported-by: "kernelci.org bot" <bot@kernelci.org> Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner2019-06-191-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* ARM: 8852/1: uaccess: use unified assembler language syntaxStefan Agner2019-04-231-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | Convert the conditional infix to a postfix to make sure this inline assembly is unified syntax. Since gcc assumes non-unified syntax when emitting ARM instructions, make sure to define the syntax as unified. This allows to use LLVM's integrated assembler. Additionally, for GCC ".syntax unified" for inline assembly. When compiling non-Thumb2 GCC always emits a ".syntax divided" at the beginning of the inline assembly which makes the assembler fail. Since GCC 5 there is the -masm-syntax-unified GCC option which make GCC assume unified syntax asm and hence emits ".syntax unified" even in ARM mode. However, the option is broken since GCC version 6 (see GCC PR88648 [1]). Work around by adding ".syntax unified" as part of the inline assembly. [0] https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html#index-masm-syntax-unified [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88648 Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2019-03-151-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: - An improvement from Ard Biesheuvel, who noted that the identity map setup was taking a long time due to flush_cache_louis(). - Update a comment about dma_ops from Wolfram Sang. - Remove use of "-p" with ld, where this flag has been a no-op since 2004. - Remove the printing of the virtual memory layout, which is no longer useful since we hide pointers. - Correct SCU help text. - Remove legacy TWD registration method. - Add pgprot_device() implementation for mapping PCI sysfs resource files. - Initialise PFN limits earlier for kmemleak. - Fix argument count to match macro definition (affects clang builds) - Use unified assembler language almost everywhere for clang, and other clang improvements (from Stefan Agner, Nathan Chancellor). - Support security extension for noMMU and other noMMU cleanups (from Vladimir Murzin). - Remove unnecessary SMP bringup code (which was incorrectly copy'n' pasted from the ARM platform implementations) and remove it from the arch code to discourge further copys of it appearing. - Add Cortex A9 erratum preventing kexec working on some SoCs. - AMBA bus identification updates from Mike Leach. - More use of raw spinlocks to avoid -RT kernel issues (from Yang Shi and Sebastian Andrzej Siewior). - MCPM hyp/svc mode mismatch fixes from Marek Szyprowski. * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits) ARM: 8849/1: NOMMU: Fix encodings for PMSAv8's PRBAR4/PRLAR4 ARM: 8848/1: virt: Align GIC version check with arm64 counterpart ARM: 8847/1: pm: fix HYP/SVC mode mismatch when MCPM is used ARM: 8845/1: use unified assembler in c files ARM: 8844/1: use unified assembler in assembly files ARM: 8843/1: use unified assembler in headers ARM: 8841/1: use unified assembler in macros ARM: 8840/1: use a raw_spinlock_t in unwind ARM: 8839/1: kprobe: make patch_lock a raw_spinlock_t ARM: 8837/1: coresight: etmv4: Update ID register table to add UCI support ARM: 8836/1: drivers: amba: Update component matching to use the CoreSight UCI values. ARM: 8838/1: drivers: amba: Updates to component identification for driver matching. ARM: 8833/1: Ensure that NEON code always compiles with Clang ARM: avoid Cortex-A9 livelock on tight dmb loops ARM: smp: remove arch-provided "pen_release" ARM: actions: remove boot_lock and pen_release ARM: oxnas: remove CPU hotplug implementation ARM: qcom: remove unnecessary boot_lock ARM: 8832/1: NOMMU: Limit visibility for CONFIG_FLASH_{MEM_BASE,SIZE} ARM: 8831/1: NOMMU: pmsa-v8: remove unneeded semicolon ...
| * ARM: 8828/1: uaccess: use unified assembler language syntaxStefan Agner2019-02-011-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Convert the conditional infix to a postfix to make sure this inline assembly is unified syntax. Since gcc assumes non-unified syntax when emitting ARM instructions, make sure to define the syntax as unified. This allows to use LLVM's integrated assembler. Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* | get rid of legacy 'get_ds()' functionLinus Torvalds2019-03-041-1/+0
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn <jannh@google.com> Inspired-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for-4.21' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2019-01-051-0/+18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: "Included in this update: - Florian Fainelli noticed that userspace segfaults caused by the lack of kernel-userspace helpers was hard to diagnose; we now issue a warning when userspace tries to use the helpers but the kernel has them disabled. - Ben Dooks wants compatibility for the old ATAG serial number with DT systems. - Some cleanup of assembly by Nicolas Pitre. - User accessors optimisation from Vincent Whitchurch. - More robust kdump on SMP systems from Yufen Wang. - Sebastian Andrzej Siewior noticed problems with the SMP "boot_lock" on RT kernels, and so we convert the Versatile series of platforms to use a raw spinlock instead, consolidating the Versatile implementation. We entirely remove the boot_lock on OMAP systems, where it's unnecessary. Further patches for other systems will be submitted for the following merge window. - Start switching old StrongARM-11x0 systems to use gpiolib rather than their private GPIO implementation - mostly PCMCIA bits. - ARM Kconfig cleanups. - Cleanup a mostly harmless mistake in the recent Spectre patch in 4.20 (which had the effect that data that can be placed into the init sections was incorrectly always placed in the rodata section)" * tag 'for-4.21' of git://git.armlinux.org.uk/~rmk/linux-arm: (25 commits) ARM: omap2: remove unnecessary boot_lock ARM: versatile: rename and comment SMP implementation ARM: versatile: convert boot_lock to raw ARM: vexpress/realview: consolidate immitation CPU hotplug ARM: fix the cockup in the previous patch ARM: sa1100/cerf: switch to using gpio_led_register_device() ARM: sa1100/assabet: switch to using gpio leds ARM: sa1100/assabet: add gpio keys support for right-hand two buttons ARM: sa1111: remove legacy GPIO interfaces pcmcia: sa1100*: remove redundant bvd1/bvd2 setting ARM: pxa/lubbock: switch PCMCIA to MAX1600 library ARM: pxa/mainstone: switch PCMCIA to MAX1600 library and gpiod APIs ARM: sa1100/neponset: switch PCMCIA to MAX1600 library and gpiod APIs ARM: sa1100/jornada720: switch PCMCIA to gpiod APIs pcmcia: add MAX1600 library ARM: sa1100: explicitly register sa11x0-pcmcia devices ARM: 8813/1: Make aligned 2-byte getuser()/putuser() atomic on ARMv6+ ARM: 8812/1: Optimise copy_{from/to}_user for !CPU_USE_DOMAINS ARM: 8811/1: always list both ldrd/strd registers explicitly ARM: 8808/1: kexec:offline panic_smp_self_stop CPU ...
| * ARM: 8813/1: Make aligned 2-byte getuser()/putuser() atomic on ARMv6+Vincent Whitchurch2018-11-121-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | getuser() and putuser() (and there underscored variants) use two strb[t]/ldrb[t] instructions when they are asked to get/put 16-bits. This means that the read/write is not atomic even when performed to a 16-bit-aligned address. This leads to problems with vhost: vhost uses __getuser() to read the vring's 16-bit avail.index field, and if it happens to observe a partial update of the index, wrong descriptors will be used which will lead to a breakdown of the virtio communication. A similar problem exists for __putuser() which is used to write to the vring's used.index field. The reason these functions use strb[t]/ldrb[t] is because strht/ldrht instructions did not exist until ARMv6T2/ARMv7. So we should be easily able to fix this on ARMv7. Also, since all ARMv6 processors also don't actually use the unprivileged instructions anymore for uaccess (since CONFIG_CPU_USE_DOMAINS is not used) we can easily fix them too. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* | Remove 'type' argument from access_ok() functionLinus Torvalds2019-01-031-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branches 'fixes', 'misc' and 'spectre' into for-nextRussell King2018-10-101-6/+43
|\
| * ARM: 8796/1: spectre-v1,v1.1: provide helpers for address sanitizationJulien Thierry2018-10-051-0/+26
| | | | | | | | | | | | | | | | | | | | Introduce C and asm helpers to sanitize user address, taking the address range they target into account. Use asm helper for existing sanitization in __copy_from_user(). Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| * ARM: 8795/1: spectre-v1.1: use put_user() for __put_user()Julien Thierry2018-10-051-6/+9
| | | | | | | | | | | | | | | | | | When Spectre mitigation is required, __put_user() needs to include check_uaccess. This is already the case for put_user(), so just make __put_user() an alias of put_user(). Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| * ARM: 8794/1: uaccess: Prevent speculative use of the current addr_limitJulien Thierry2018-10-051-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A mispredicted conditional call to set_fs could result in the wrong addr_limit being forwarded under speculation to a subsequent access_ok check, potentially forming part of a spectre-v1 attack using uaccess routines. This patch prevents this forwarding from taking place, but putting heavy barriers in set_fs after writing the addr_limit. Porting commit c2f0ad4fc089cff8 ("arm64: uaccess: Prevent speculative use of the current addr_limit"). Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* | Merge branches 'fixes', 'misc' and 'spectre' into for-linusRussell King2018-08-131-7/+19
|\| | | | | | | | | | | | | Conflicts: arch/arm/include/asm/uaccess.h Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| * ARM: spectre-v1: use get_user() for __get_user()Russell King2018-08-021-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Fixing __get_user() for spectre variant 1 is not sane: we would have to add address space bounds checking in order to validate that the location should be accessed, and then zero the address if found to be invalid. Since __get_user() is supposed to avoid the bounds check, and this is exactly what get_user() does, there's no point having two different implementations that are doing the same thing. So, when the Spectre workarounds are required, make __get_user() an alias of get_user(). Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| * ARM: use __inttype() in get_user()Russell King2018-08-021-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | Borrow the x86 implementation of __inttype() to use in get_user() to select an integer type suitable to temporarily hold the result value. This is necessary to avoid propagating the volatile nature of the result argument, which can cause the following warning: lib/iov_iter.c:413:5: warning: optimization may eliminate reads and/or writes to register variables [-Wvolatile-register-var] Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* | ARM: 8768/1: uaccess: remove const to avoid duplicate specifierStefan Agner2018-05-191-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some users of get_user use the macro with an argument p which is already specified as static. When using clang this leads to a duplicate specifier: CC arch/arm/kernel/process.o In file included from init/do_mounts.c:15: In file included from ./include/linux/tty.h:7: In file included from ./include/uapi/linux/termios.h:6: In file included from ./arch/arm/include/generated/uapi/asm/termios.h:1: ./include/asm-generic/termios.h:25:6: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier] if (get_user(tmp, &termio->c_iflag) < 0) ^ ./arch/arm/include/asm/uaccess.h:195:3: note: expanded from macro 'get_user' __get_user_check(x, p); ^ ./arch/arm/include/asm/uaccess.h:155:12: note: expanded from macro '__get_user_check' register const typeof(*(p)) __user *__p asm("r0") = (p); Remove the const attribute from the register declaration to avoid the duplicate const specifier. In a test with ptrace.c and traps.c (both using get_user with non-const arguments for p) the generated code was exactly the same. Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* Revert "arm/syscalls: Check address limit on user-mode return"Thomas Garnier2017-09-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 73ac5d6a2b6ac3ae8d1e1818f3e9946f97489bc9. The work pending loop can call set_fs after addr_limit_user_check removed the _TIF_FSCHECK flag. This may happen at anytime based on how ARM handles alignment exceptions. It leads to an infinite loop condition. After discussion, it has been agreed that the generic approach is not tailored to the ARM architecture and any fix might not be complete. This patch will be replaced by an architecture specific implementation. The work flag approach will be kept for other architectures. Reported-by: Leonard Crestez <leonard.crestez@nxp.com> Signed-off-by: Thomas Garnier <thgarnie@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Pratyush Anand <panand@redhat.com> Cc: Dave Martin <Dave.Martin@arm.com> Cc: Will Drewry <wad@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Andy Lutomirski <luto@amacapital.net> Cc: David Howells <dhowells@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-api@vger.kernel.org Cc: Yonghong Song <yhs@fb.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1504798247-48833-3-git-send-email-keescook@chromium.org
* Merge branch 'x86-syscall-for-linus' of ↵Linus Torvalds2017-09-041-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull syscall updates from Ingo Molnar: "Improve the security of set_fs(): we now check the address limit on a number of key platforms (x86, arm, arm64) before returning to user-space - without adding overhead to the typical system call fast path" * 'x86-syscall-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: arm64/syscalls: Check address limit on user-mode return arm/syscalls: Check address limit on user-mode return x86/syscalls: Check address limit on user-mode return
| * arm/syscalls: Check address limit on user-mode returnThomas Garnier2017-07-081-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ensure the address limit is a user-mode segment before returning to user-mode. Otherwise a process can corrupt kernel-mode memory and elevate privileges [1]. The set_fs function sets the TIF_SETFS flag to force a slow path on return. In the slow path, the address limit is checked to be USER_DS if needed. The TIF_SETFS flag is added to _TIF_WORK_MASK shifting _TIF_SYSCALL_WORK for arm instruction immediate support. The global work mask is too big to used on a single instruction so adapt ret_fast_syscall. [1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990 Signed-off-by: Thomas Garnier <thgarnie@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: kernel-hardening@lists.openwall.com Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: David Howells <dhowells@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Pratyush Anand <panand@redhat.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Petr Mladek <pmladek@suse.com> Cc: Rik van Riel <riel@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Will Drewry <wad@chromium.org> Cc: linux-api@vger.kernel.org Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/20170615011203.144108-2-thgarnie@google.com
* | Merge branch 'work.uaccess-unaligned' of ↵Linus Torvalds2017-07-151-7/+0
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull uacess-unaligned removal from Al Viro: "That stuff had just one user, and an exotic one, at that - binfmt_flat on arm and m68k" * 'work.uaccess-unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: kill {__,}{get,put}_user_unaligned() binfmt_flat: flat_{get,put}_addr_from_rp() should be able to fail
| * | kill {__,}{get,put}_user_unaligned()Al Viro2017-07-031-7/+0
| |/ | | | | | | | | | | no users left Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* / kill strlen_user()Al Viro2017-05-151-1/+0
|/ | | | | | no callers, no consistent semantics, no sane way to use it... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* arm: switch to RAW_COPY_USERAl Viro2017-03-281-46/+14
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* arm: switch to generic extable.hAl Viro2017-03-281-19/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: uaccess_kernel()Al Viro2017-03-281-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* uaccess: drop duplicate includes from asm/uaccess.hAl Viro2017-03-051-2/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* uaccess: move VERIFY_{READ,WRITE} definitions to linux/uaccess.hAl Viro2017-03-051-3/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ARM: 8657/1: uaccess: consistently check object sizesKees Cook2017-02-161-12/+32
| | | | | | | | | | | | | | | In commit 76624175dcae ("arm64: uaccess: consistently check object sizes"), the object size checks are moved outside the access_ok() so that bad destinations are detected before hitting the "memset(dest, 0, size)" in the copy_from_user() failure path. This makes the same change for arm, with attention given to possibly extracting the uaccess routines into a common header file for all architectures in the future. Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()Al Viro2016-09-151-5/+6
| | | | | | adjust copy_from_user(), obviously Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge tag 'usercopy-v4.8' of ↵Linus Torvalds2016-08-081-2/+9
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull usercopy protection from Kees Cook: "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and copy_from_user bounds checking for most architectures on SLAB and SLUB" * tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: mm: SLUB hardened usercopy support mm: SLAB hardened usercopy support s390/uaccess: Enable hardened usercopy sparc/uaccess: Enable hardened usercopy powerpc/uaccess: Enable hardened usercopy ia64/uaccess: Enable hardened usercopy arm64/uaccess: Enable hardened usercopy ARM: uaccess: Enable hardened usercopy x86/uaccess: Enable hardened usercopy mm: Hardened usercopy mm: Implement stack frame object validation mm: Add is_migrate_cma_page
| * ARM: uaccess: Enable hardened usercopyKees Cook2016-07-261-2/+9
| | | | | | | | | | | | | | | | Enables CONFIG_HARDENED_USERCOPY checks on arm. Based on code from PaX and grsecurity. Signed-off-by: Kees Cook <keescook@chromium.org>
* | ARM: uaccess: remove put_user() code duplicationRussell King2016-06-221-57/+49
| | | | | | | | | | | | | | | | | | Remove the code duplication between put_user() and __put_user(). The code which selected the implementation based upon the pointer size, and declared the local variable to hold the value to be put are common to both implementations. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* | ARM: 8580/1: Remove orphaned __addr_ok() definitionRobin Murphy2016-06-221-8/+0
|/ | | | | | | | | | Since commit 8c56cc8be5b3 ("ARM: 7449/1: use generic strnlen_user and strncpy_from_user functions"), the definition of __addr_ok() has been languishing unused; eradicate the sucker. Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: fix uaccess_with_memcpy() with SW_DOMAIN_PANRussell King2015-12-151-0/+4
| | | | | | | | | | | | The uaccess_with_memcpy() code is currently incompatible with the SW PAN code: it takes locks within the region that we've changed the DACR, potentially sleeping as a result. As we do not save and restore the DACR across co-operative sleep events, can lead to an incorrect DACR value later in this code path. Reported-by: Peter Rosin <peda@axentia.se> Tested-by: Peter Rosin <peda@axentia.se> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
*-. Merge branches 'cleanup', 'fixes', 'misc', 'omap-barrier' and 'uaccess' into ↵Russell King2015-09-031-5/+80
|\ \ | | | | | | | | | for-linus
| | * ARM: software-based priviledged-no-access supportRussell King2015-08-261-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide a software-based implementation of the priviledged no access support found in ARMv8.1. Userspace pages are mapped using a different domain number from the kernel and IO mappings. If we switch the user domain to "no access" when we enter the kernel, we can prevent the kernel from touching userspace. However, the kernel needs to be able to access userspace via the various user accessor functions. With the wrapping in the previous patch, we can temporarily enable access when the kernel needs user access, and re-disable it afterwards. This allows us to trap non-intended accesses to userspace, eg, caused by an inadvertent dereference of the LIST_POISON* values, which, with appropriate user mappings setup, can be made to succeed. This in turn can allow use-after-free bugs to be further exploited than would otherwise be possible. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| | * ARM: uaccess: provide uaccess_save_and_enable() and uaccess_restore()Russell King2015-08-251-5/+66
| |/ | | | | | | | | | | | | | | | | Provide uaccess_save_and_enable() and uaccess_restore() to permit control of userspace visibility to the kernel, and hook these into the appropriate places in the kernel where we need to access userspace. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* / ARM: uaccess: simplify user access assemblyRussell King2015-08-251-35/+12
|/ | | | | | | | The user assembly for byte and word accesses was virtually identical. Rather than duplicating this, use a macro instead. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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