From: Rik van Riel <riel@xxxxxxxxxx> Subject: arm64: ascii armor the arm64 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/20170524155751.424-5-riel@xxxxxxxxxx Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Daniel Micay <danielmicay@xxxxxxxxx> Cc: "Theodore Ts'o" <tytso@xxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/stackprotector.h | 1 + 1 file changed, 1 insertion(+) diff -puN arch/arm64/include/asm/stackprotector.h~arm64-ascii-armor-the-arm64-boot-init-stack-canary arch/arm64/include/asm/stackprotector.h --- a/arch/arm64/include/asm/stackprotector.h~arm64-ascii-armor-the-arm64-boot-init-stack-canary +++ a/arch/arm64/include/asm/stackprotector.h @@ -30,6 +30,7 @@ static __always_inline void boot_init_st /* 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
