Messages in this thread | | | From | Kees Cook <> | Date | Wed, 24 May 2017 09:16:51 -0700 | Subject | Re: [PATCH 4/5] arm64: ascii armor the arm64 boot init stack canary |
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On Wed, May 24, 2017 at 8:57 AM, <riel@redhat.com> wrote: > 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 Daniel Micay's linux-hardened tree. > > Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
> --- > arch/arm64/include/asm/stackprotector.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/include/asm/stackprotector.h b/arch/arm64/include/asm/stackprotector.h > index fe5e287dc56b..b86a0865ddf1 100644 > --- a/arch/arm64/include/asm/stackprotector.h > +++ b/arch/arm64/include/asm/stackprotector.h > @@ -30,6 +30,7 @@ static __always_inline void boot_init_stack_canary(void) > /* Try to get a semi random initial value. */ > get_random_bytes(&canary, sizeof(canary)); > canary ^= LINUX_VERSION_CODE; > + canary &= CANARY_MASK; > > current->stack_canary = canary; > __stack_chk_guard = current->stack_canary; > -- > 2.9.3 >
-- Kees Cook Pixel Security
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