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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-09 00:48:14 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-08-09 00:48:14 +0300 |
commit | 1eccfa090eaea22558570054bbdc147817e1df5e (patch) | |
tree | a0adfdb87319abef88f575ee34314649193b7e92 /arch/x86/include/asm/thread_info.h | |
parent | 1bd4403d86a1c06cb6cc9ac87664a0c9d3413d51 (diff) | |
parent | ed18adc1cdd00a5c55a20fbdaed4804660772281 (diff) | |
download | linux-1eccfa090eaea22558570054bbdc147817e1df5e.tar.xz |
Merge tag 'usercopy-v4.8' of 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
Diffstat (limited to 'arch/x86/include/asm/thread_info.h')
-rw-r--r-- | arch/x86/include/asm/thread_info.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 84b59846154a..8b7c8d8e0852 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -176,6 +176,50 @@ static inline unsigned long current_stack_pointer(void) return sp; } +/* + * Walks up the stack frames to make sure that the specified object is + * entirely contained by a single stack frame. + * + * Returns: + * 1 if within a frame + * -1 if placed across a frame boundary (or outside stack) + * 0 unable to determine (no frame pointers, etc) + */ +static inline int arch_within_stack_frames(const void * const stack, + const void * const stackend, + const void *obj, unsigned long len) +{ +#if defined(CONFIG_FRAME_POINTER) + const void *frame = NULL; + const void *oldframe; + + oldframe = __builtin_frame_address(1); + if (oldframe) + frame = __builtin_frame_address(2); + /* + * low ----------------------------------------------> high + * [saved bp][saved ip][args][local vars][saved bp][saved ip] + * ^----------------^ + * allow copies only within here + */ + while (stack <= frame && frame < stackend) { + /* + * If obj + len extends past the last frame, this + * check won't pass and the next frame will be 0, + * causing us to bail out and correctly report + * the copy as invalid. + */ + if (obj + len <= frame) + return obj >= oldframe + 2 * sizeof(void *) ? 1 : -1; + oldframe = frame; + frame = *(const void * const *)frame; + } + return -1; +#else + return 0; +#endif +} + #else /* !__ASSEMBLY__ */ #ifdef CONFIG_X86_64 |