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Groups > linux.kernel > #1645964
| From | riel@redhat.com |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3/5] x86: ascii armor the x86_64 boot init stack canary |
| Date | 2017-05-19 23:40 +0200 |
| Message-ID | <tIXMR-86v-9@gated-at.bofh.it> (permalink) |
| References | <tIXMR-86v-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Rik van Riel <riel@redhat.com> 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 PaX/grsecurity. Signed-off-by: Rik van Riel <riel@redhat.com> --- arch/x86/include/asm/stackprotector.h | 1 + 1 file changed, 1 insertion(+) 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 -- 2.9.3
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[PATCH 3/5] x86: ascii armor the x86_64 boot init stack canary riel@redhat.com - 2017-05-19 23:40 +0200
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