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Subject[PATCH 1/3] sh/boot: Add static stack-protector to pre-kernel
Date
The sh decompressor code triggers stack-protector code generation when
using CONFIG_CC_STACKPROTECTOR_STRONG. As done for arm and mips, add a
simple static stack-protector canary. As this wasn't protected before, the
risk of using a weak canary is minimized. Once the kernel is actually up,
a better canary is chosen.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/sh/boot/compressed/misc.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
index ae1dfdb0013b..f4bdc5d00c04 100644
--- a/arch/sh/boot/compressed/misc.c
+++ b/arch/sh/boot/compressed/misc.c
@@ -103,6 +103,18 @@ static void error(char *x)
while(1); /* Halt */
}

+unsigned long __stack_chk_guard;
+
+void __stack_chk_guard_setup(void)
+{
+ __stack_chk_guard = 0x000a0dff;
+}
+
+void __stack_chk_fail(void)
+{
+ error("stack-protector: Kernel stack is corrupted\n");
+}
+
#ifdef CONFIG_SUPERH64
#define stackalign 8
#else
@@ -117,6 +129,8 @@ void decompress_kernel(void)
{
unsigned long output_addr;

+ __stack_chk_guard_setup();
+
#ifdef CONFIG_SUPERH64
output_addr = (CONFIG_MEMORY_START + 0x2000);
#else
--
2.7.4
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