[PATCH 07/08] NET: Ensure device name passed to SO_BINDTODEVICE is NULL terminated.

[Greg KH <gregkh@suse.de>]

From: "David S. Miller" <davem@davemloft.net>

The user can pass us arbitrary garbage so we should ensure the
string they give us is null terminated before we pass it on
to dev_get_by_index() et al.

Found by Solar Designer.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

 net/core/sock.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- linux-2.6.15.6.orig/net/core/sock.c
+++ linux-2.6.15.6/net/core/sock.c
@@ -403,8 +403,9 @@ set_rcvbuf:
 			if (!valbool) {
 				sk->sk_bound_dev_if = 0;
 			} else {
-				if (optlen > IFNAMSIZ) 
-					optlen = IFNAMSIZ; 
+				if (optlen > IFNAMSIZ - 1)
+					optlen = IFNAMSIZ - 1;
+				memset(devname, 0, sizeof(devname));
 				if (copy_from_user(devname, optval, optlen)) {
 					ret = -EFAULT;
 					break;