From ba8379b220509e9448c00a77cf6c15ac2a559cc7 Mon Sep 17 00:00:00 2001
From: Chris Wright <chrisw@sous-sol.org>
Date: Mon, 20 Nov 2006 15:02:49 -0800
Subject: [PATCH] [PATCH] bridge: fix possible overflow in get_fdb_entries
Make sure to properly clamp maxnum to avoid overflow
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Acked-by: Eugene Teo <eteo@redhat.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
net/bridge/br_ioctl.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 4e4119a12139..4c61a7e0a86e 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -58,12 +58,13 @@ static int get_fdb_entries(struct net_bridge *br, void __user *userbuf,
{
int num;
void *buf;
- size_t size = maxnum * sizeof(struct __fdb_entry);
+ size_t size;
- if (size > PAGE_SIZE) {
- size = PAGE_SIZE;
+ /* Clamp size to PAGE_SIZE, test maxnum to avoid overflow */
+ if (maxnum > PAGE_SIZE/sizeof(struct __fdb_entry))
maxnum = PAGE_SIZE/sizeof(struct __fdb_entry);
- }
+
+ size = maxnum * sizeof(struct __fdb_entry);
buf = kmalloc(size, GFP_USER);
if (!buf)
--
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