[NET]: Ensure device name passed to SO_BINDTODEVICE is NULL terminated.

Found by Solar Designer.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/core/sock.c b/net/core/sock.c
index 1a7e6eac90b0..e110b9004147 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -404,8 +404,9 @@ 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;