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authorJosh Boyer <jwboyer@linux.vnet.ibm.com>2009-03-25 06:23:59 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-03-27 16:58:24 +1100
commitefbda86098455da014be849713df6498cefc5a2a (patch)
treefb239d51dd521bb2976807eeedfacd17be9b6824 /arch/powerpc/kernel/signal.c
parent82631f5dd114e52239fb3d1e270a49d37c088b46 (diff)
downloadop-kernel-dev-efbda86098455da014be849713df6498cefc5a2a.zip
op-kernel-dev-efbda86098455da014be849713df6498cefc5a2a.tar.gz
powerpc: Sanitize stack pointer in signal handling code
On powerpc64 machines running 32-bit userspace, we can get garbage bits in the stack pointer passed into the kernel. Most places handle this correctly, but the signal handling code uses the passed value directly for allocating signal stack frames. This fixes the issue by introducing a get_clean_sp function that returns a sanitized stack pointer. For 32-bit tasks on a 64-bit kernel, the stack pointer is masked correctly. In all other cases, the stack pointer is simply returned. Additionally, we pass an 'is_32' parameter to get_sigframe now in order to get the properly sanitized stack. The callers are know to be 32 or 64-bit statically. Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/signal.c')
-rw-r--r--arch/powerpc/kernel/signal.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index a54405e..00b5078 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -26,12 +26,12 @@ int show_unhandled_signals = 0;
* Allocate space for the signal frame
*/
void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
- size_t frame_size)
+ size_t frame_size, int is_32)
{
unsigned long oldsp, newsp;
/* Default to using normal stack */
- oldsp = regs->gpr[1];
+ oldsp = get_clean_sp(regs, is_32);
/* Check for alt stack */
if ((ka->sa.sa_flags & SA_ONSTACK) &&
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