diff options
| author | Tejun Heo <tj@kernel.org> | 2009-02-11 10:31:00 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-02-11 13:33:49 +0300 |
| commit | 5c79d2a517a9905599d192db8ce77ab5f1a2faca (patch) | |
| tree | 11f550a59b9b653fbd6c54b37effbf2d4a750fb5 /arch/x86/kernel/process_64.c | |
| parent | 60a5317ff0f42dd313094b88f809f63041568b08 (diff) | |
| download | linux-5c79d2a517a9905599d192db8ce77ab5f1a2faca.tar.xz | |
x86: fix x86_32 stack protector bugs
Impact: fix x86_32 stack protector
Brian Gerst found out that %gs was being initialized to stack_canary
instead of stack_canary - 20, which basically gave the same canary
value for all threads. Fixing this also exposed the following bugs.
* cpu_idle() didn't call boot_init_stack_canary()
* stack canary switching in switch_to() was being done too late making
the initial run of a new thread use the old stack canary value.
Fix all of them and while at it update comment in cpu_idle() about
calling boot_init_stack_canary().
Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/process_64.c')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 8eb169e45584..836ef6575f01 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -120,12 +120,11 @@ void cpu_idle(void) current_thread_info()->status |= TS_POLLING; /* - * 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): + * If we're the non-boot CPU, nothing set the stack canary up + * for us. CPU0 already has it initialized but no harm in + * doing it again. 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). */ boot_init_stack_canary(); |