From mboxrd@z Thu Jan 1 00:00:00 1970 From: keescook@google.com (Kees Cook) Date: Wed, 24 May 2017 09:35:38 -0700 Subject: [PATCH 5/5] sh64: ascii armor the sh64 boot init stack canary In-Reply-To: <20170524123446.78510066@annuminas.surriel.com> References: <20170524155751.424-1-riel@redhat.com> <20170524123446.78510066@annuminas.surriel.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, May 24, 2017 at 9:34 AM, Rik van Riel 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 Acked-by: Kees Cook -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; > -- Kees Cook Pixel Security