[PATCH] Add the Kconfig option for the stackprotector feature

This patch adds the config options for -fstack-protector.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
CC: Andi Kleen <ak@suse.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 927b392a4aa0..0c61d0019dd7 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -533,6 +533,30 @@ config SECCOMP
 
           If unsure, say Y. Only embedded should say N here.
 
+config CC_STACKPROTECTOR
+        bool "Enable -fstack-protector buffer overflow detection (EXPRIMENTAL)"
+        depends on EXPERIMENTAL
+        help
+         This option turns on the -fstack-protector GCC feature. This
+          feature puts, at the beginning of critical functions, a canary
+          value on the stack just before the return address, and validates
+          the value just before actually returning.  Stack based buffer
+          overflows (that need to overwrite this return address) now also
+          overwrite the canary, which gets detected and the attack is then
+          neutralized via a kernel panic.
+
+          This feature requires gcc version 4.2 or above, or a distribution
+          gcc with the feature backported. Older versions are automatically
+          detected and for those versions, this configuration option is ignored.
+
+config CC_STACKPROTECTOR_ALL
+        bool "Use stack-protector for all functions"
+        depends on CC_STACKPROTECTOR
+        help
+          Normally, GCC only inserts the canary value protection for
+          functions that use large-ish on-stack buffers. By enabling
+          this option, GCC will be asked to do this for ALL functions.
+
 source kernel/Kconfig.hz
 
 config REORDER