[patch 4/5] -fstack-protector feature: Add the __stack_chk_fail()function

From: Arjan van de Ven
Date: Wed Aug 16 2006 - 13:08:47 EST

Subject: [patch 4/5] Add the __stack_chk_fail() function

GCC emits a call to a __stack_chk_fail() function when the stack canary is
not matching the expected value.

Since this is a bad security issue; lets panic the kernel rather than limping
along; the kernel really can't be trusted anymore when this happens.

Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
CC: Andi Kleen <ak@xxxxxxx>

kernel/panic.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

Index: linux-2.6.18-rc4-stackprot/kernel/panic.c
--- linux-2.6.18-rc4-stackprot.orig/kernel/panic.c
+++ linux-2.6.18-rc4-stackprot/kernel/panic.c
@@ -269,3 +269,15 @@ void oops_exit(void)
+ * Called when gcc's -fstack-protector feature is used, and
+ * gcc detects corruption of the on-stack canary value
+ */
+void __stack_chk_fail(void)
+ panic("stack-protector: Kernel stack is corrupted");

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