diff options
| author | Ingo Molnar <mingo@elte.hu> | 2008-02-14 09:56:04 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-05-26 16:15:32 +0200 |
| commit | 960a672bd9f1ec06e8f197cf81a50fd07ea02e7f (patch) | |
| tree | ed7372988fb2ca06f0a3dd4719652ab2d370153c /include | |
| parent | 420594296838fdc9a674470d710cda7d1487f9f4 (diff) | |
x86: stackprotector: mix TSC to the boot canary
mix the TSC to the boot canary.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-x86/stackprotector.h | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/include/asm-x86/stackprotector.h b/include/asm-x86/stackprotector.h index 0f91f7a2688c..3baf7ad89be1 100644 --- a/include/asm-x86/stackprotector.h +++ b/include/asm-x86/stackprotector.h @@ -1,6 +1,8 @@ #ifndef _ASM_STACKPROTECTOR_H #define _ASM_STACKPROTECTOR_H 1 +#include <asm/tsc.h> + /* * Initialize the stackprotector canary value. * @@ -9,16 +11,28 @@ */ static __always_inline void boot_init_stack_canary(void) { + u64 canary; + u64 tsc; + /* * If we're the non-boot CPU, nothing set the PDA stack * canary up for us - and if we are the boot CPU we have * a 0 stack canary. This is a good place for updating * it, as we wont ever return from this function (so the * invalid canaries already on the stack wont ever - * trigger): + * trigger). + * + * We both use the random pool and the current TSC as a source + * of randomness. The TSC only matters for very early init, + * there it already has some randomness on most systems. Later + * on during the bootup the random pool has true entropy too. */ - current->stack_canary = get_random_int(); - write_pda(stack_canary, current->stack_canary); + get_random_bytes(&canary, sizeof(canary)); + tsc = __native_read_tsc(); + canary += tsc + (tsc << 32UL); + + current->stack_canary = canary; + write_pda(stack_canary, canary); } #endif |