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author | Nicolas Pitre <nico@fluxnic.net> | 2010-05-24 23:55:42 -0400 |
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committer | Nicolas Pitre <nico@fluxnic.net> | 2010-06-14 21:31:00 -0400 |
commit | c743f38013aeff58ef6252601e397b5ba281c633 (patch) | |
tree | b364e1690aff8a0dd97a83d4cb17bcadcdb5bd19 /arch/arm/include | |
parent | cc92c28b2db5b406657ecc05235d4ca4e222ae34 (diff) | |
download | op-kernel-dev-c743f38013aeff58ef6252601e397b5ba281c633.zip op-kernel-dev-c743f38013aeff58ef6252601e397b5ba281c633.tar.gz |
ARM: initial stack protector (-fstack-protector) support
This is the very basic stuff without the changing canary upon
task switch yet. Just the Kconfig option and a constant canary
value initialized at boot time.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Diffstat (limited to 'arch/arm/include')
-rw-r--r-- | arch/arm/include/asm/stackprotector.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/arm/include/asm/stackprotector.h b/arch/arm/include/asm/stackprotector.h new file mode 100644 index 0000000..de00332 --- /dev/null +++ b/arch/arm/include/asm/stackprotector.h @@ -0,0 +1,38 @@ +/* + * GCC stack protector support. + * + * Stack protector works by putting predefined pattern at the start of + * the stack frame and verifying that it hasn't been overwritten when + * returning from the function. The pattern is called stack canary + * and gcc expects it to be defined by a global variable called + * "__stack_chk_guard" on ARM. This unfortunately means that on SMP + * we cannot have a different canary value per task. + */ + +#ifndef _ASM_STACKPROTECTOR_H +#define _ASM_STACKPROTECTOR_H 1 + +#include <linux/random.h> +#include <linux/version.h> + +extern unsigned long __stack_chk_guard; + +/* + * Initialize the stackprotector canary value. + * + * NOTE: this must only be called from functions that never return, + * and it must always be inlined. + */ +static __always_inline void boot_init_stack_canary(void) +{ + unsigned long canary; + + /* Try to get a semi random initial value. */ + get_random_bytes(&canary, sizeof(canary)); + canary ^= LINUX_VERSION_CODE; + + current->stack_canary = canary; + __stack_chk_guard = current->stack_canary; +} + +#endif /* _ASM_STACKPROTECTOR_H */ |