[PATCH] bridge: fix possible overflow in get_fdb_entries

ba8379b2 · Chris Wright <[email protected]> · 2006-11-20 15:02:49 -08:00

Make sure to properly clamp maxnum to avoid overflow

Signed-off-by: Chris Wright <[email protected]>
Acked-by: Eugene Teo <[email protected]>
Acked-by: Marcel Holtmann <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: ba8379b220509e9448c00a77cf6c15ac2a559cc7
Parents: 24d7bb33

Changes

1 files changed · +5 −4

File	Status	Add	Del	Content
net/bridge/br_ioctl.c	modified	+5	−4	View file

net/bridge/br_ioctl.c

View file

diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 4e4119a..4c61a7e 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)