From: David S. Miller <davem@davemloft.net>
Date: Fri, 8 Aug 2008 06:04:37 +0000 (-0700)
Subject: sparc64: Fix end-of-stack checking in save_stack_trace().
X-Git-Tag: v2.6.27-rc3~70^2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=433c5f706856689be25928a99636e724fb3ea7cf;p=linux-2.6

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>
---

diff --git a/arch/sparc64/kernel/stacktrace.c b/arch/sparc64/kernel/stacktrace.c
index b3e3737750..e9d7f0660f 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;