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authorRik van Riel <riel@redhat.com>2017-07-13 00:36:26 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-13 02:26:03 +0300
commitd21f54988bb2927341757d42152440c3abcae4eb (patch)
tree57083344d6829e1b6a22d246bcb44988d8198bfd /arch/arm64/include/asm/stackprotector.h
parentbf9eb5443844e288b73f7963dfc67a0d2fbc3849 (diff)
downloadlinux-d21f54988bb2927341757d42152440c3abcae4eb.tar.xz
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@redhat.com Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Daniel Micay <danielmicay@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm64/include/asm/stackprotector.h')
-rw-r--r--arch/arm64/include/asm/stackprotector.h1
1 files changed, 1 insertions, 0 deletions
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;