diff options
| author | Tejun Heo <tj@kernel.org> | 2009-02-09 22:17:40 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-02-10 00:42:01 +0100 |
| commit | 60a5317ff0f42dd313094b88f809f63041568b08 (patch) | |
| tree | 307dfd9715fbc9ff83c3c3ae3b0e8f03888083f2 /arch/x86/kernel/entry_32.S | |
| parent | ccbeed3a05908d201b47b6c3dd1a373138bba566 (diff) | |
x86: implement x86_32 stack protector
Impact: stack protector for x86_32
Implement stack protector for x86_32. GDT entry 28 is used for it.
It's set to point to stack_canary-20 and have the length of 24 bytes.
CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs
to the stack canary segment on entry. As %gs is otherwise unused by
the kernel, the canary can be anywhere. It's defined as a percpu
variable.
x86_32 exception handlers take register frame on stack directly as
struct pt_regs. With -fstack-protector turned on, gcc copies the
whole structure after the stack canary and (of course) doesn't copy
back on return thus losing all changed. For now, -fno-stack-protector
is added to all files which contain those functions. We definitely
need something better.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/entry_32.S')
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 82e6868bee4..5f5bd22adcd 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -186,7 +186,7 @@ /*CFI_REL_OFFSET gs, PT_GS*/ .endm .macro SET_KERNEL_GS reg - xorl \reg, \reg + movl $(__KERNEL_STACK_CANARY), \reg movl \reg, %gs .endm |