[PATCH] powerpc: Add out of bounds check to crash_shutdown_unregister()

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

When unregistering a crash_shutdown_handle in the function
crash_shutdown_unregister() the other handles are shifted down in the
array to replace the unregistered handle. The for loop assumes that the
last element in the array is null and uses this as the stop condition,
however in the case that the last element is not null there is no check
to ensure that an out of bounds access is not performed.

Add a check to terminate the shift operation when CRASH_HANDLER_MAX is
reached in order to protect against out of bounds accesses.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---
 arch/powerpc/kernel/crash.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 2bb252c..6b267af 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -288,7 +288,7 @@ int crash_shutdown_unregister(crash_shutdown_t handler)
 		rc = 1;
 	} else {
 		/* Shift handles down */
-		for (; crash_shutdown_handles[i]; i++)
+		for (; crash_shutdown_handles[i] && i < CRASH_HANDLER_MAX; i++)
 			crash_shutdown_handles[i] =
 				crash_shutdown_handles[i+1];
 		rc = 0;
-- 
2.5.0