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| author | Rik van Riel <riel@redhat.com> | 2017-07-12 23:36:23 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-13 01:26:03 +0200 |
| commit | bf9eb5443844e288b73f7963dfc67a0d2fbc3849 (patch) | |
| tree | 1891d6e309923092a4f6bd8bede3ae37ccb50be6 | |
| parent | fork,random: use get_random_canary() to set tsk->stack_canary (diff) | |
| download | linux-bf9eb5443844e288b73f7963dfc67a0d2fbc3849.tar.xz linux-bf9eb5443844e288b73f7963dfc67a0d2fbc3849.zip | |
x86: ascii armor the x86_64 boot init stack canary
Use the ascii-armor canary to prevent unterminated C string overflows
from being able to successfully overwrite the canary, even if they
somehow obtain the canary value.
Inspired by execshield ascii-armor and Daniel Micay's linux-hardened
tree.
Link: http://lkml.kernel.org/r/20170524155751.424-4-riel@redhat.com
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86/include/asm/stackprotector.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h index dcbd9bcce714..8abedf1d650e 100644 --- a/arch/x86/include/asm/stackprotector.h +++ b/arch/x86/include/asm/stackprotector.h @@ -74,6 +74,7 @@ static __always_inline void boot_init_stack_canary(void) get_random_bytes(&canary, sizeof(canary)); tsc = rdtsc(); canary += tsc + (tsc << 32UL); + canary &= CANARY_MASK; current->stack_canary = canary; #ifdef CONFIG_X86_64 |