| Message ID | 20170524123446.78510066@annuminas.surriel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, May 24, 2017 at 9:34 AM, Rik van Riel <riel@redhat.com> wrote: > 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/sh/include/asm/stackprotector.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/sh/include/asm/stackprotector.h b/arch/sh/include/asm/stackprotector.h > index d9df3a76847c..141515a43b78 100644 > --- a/arch/sh/include/asm/stackprotector.h > +++ b/arch/sh/include/asm/stackprotector.h > @@ -19,6 +19,7 @@ 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; >
diff --git a/arch/sh/include/asm/stackprotector.h b/arch/sh/include/asm/stackprotector.h index d9df3a76847c..141515a43b78 100644 --- a/arch/sh/include/asm/stackprotector.h +++ b/arch/sh/include/asm/stackprotector.h @@ -19,6 +19,7 @@ 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;
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> --- arch/sh/include/asm/stackprotector.h | 1 + 1 file changed, 1 insertion(+)