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

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>

diff --git a/net/core/sock.c b/net/core/sock.c
index 6e00811d44bc810a8e7d6cf64585a520dc60fce2..5621198f18ec0133c387e4358dab80b3d0e869ff 100644 (file)
--- 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;