From 433c5f706856689be25928a99636e724fb3ea7cf Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Thu, 7 Aug 2008 23:04:37 -0700
Subject: [PATCH] sparc64: Fix end-of-stack checking in save_stack_trace().
Bug reported by Alexander Beregalov.
Before we dereference the stack frame or try to peek at the
pt_regs magic value, make sure the entire object is within
the kernel stack bounds.
Signed-off-by: David S. Miller <davem@davemloft.net>
---
arch/sparc64/kernel/stacktrace.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/sparc64/kernel/stacktrace.c b/arch/sparc64/kernel/stacktrace.c
index b3e3737750d8..e9d7f0660f2e 100644
--- a/arch/sparc64/kernel/stacktrace.c
+++ b/arch/sparc64/kernel/stacktrace.c
@@ -26,13 +26,15 @@ void save_stack_trace(struct stack_trace *trace)
/* Bogus frame pointer? */
if (fp < (thread_base + sizeof(struct thread_info)) ||
- fp >= (thread_base + THREAD_SIZE))
+ fp > (thread_base + THREAD_SIZE - sizeof(struct sparc_stackf)))
break;
sf = (struct sparc_stackf *) fp;
regs = (struct pt_regs *) (sf + 1);
- if ((regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
+ if (((unsigned long)regs <=
+ (thread_base + THREAD_SIZE - sizeof(*regs))) &&
+ (regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
if (!(regs->tstate & TSTATE_PRIV))
break;
pc = regs->tpc;
--
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