Bluetooth: Validate PSM values in calls to connect() and bind()

Valid L2CAP PSMs are odd numbers, and the least significant bit of the
most significant byte must be 0.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 0b54b7d..2f625b8 100644 (file)
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1008,10 +1008,20 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
                goto done;
        }
 
-       if (la.l2_psm && __le16_to_cpu(la.l2_psm) < 0x1001 &&
-                               !capable(CAP_NET_BIND_SERVICE)) {
-               err = -EACCES;
-               goto done;
+       if (la.l2_psm) {
+               __u16 psm = __le16_to_cpu(la.l2_psm);
+
+               /* PSM must be odd and lsb of upper byte must be 0 */
+               if ((psm & 0x0101) != 0x0001) {
+                       err = -EINVAL;
+                       goto done;
+               }
+
+               /* Restrict usage of well-known PSMs */
+               if (psm < 0x1001 && !capable(CAP_NET_BIND_SERVICE)) {
+                       err = -EACCES;
+                       goto done;
+               }
        }
 
        write_lock_bh(&l2cap_sk_list.lock);
@@ -1190,6 +1200,13 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr, int al
                goto done;
        }
 
+       /* PSM must be odd and lsb of upper byte must be 0 */
+       if ((__le16_to_cpu(la.l2_psm) & 0x0101) != 0x0001 &&
+               sk->sk_type != SOCK_RAW) {
+               err = -EINVAL;
+               goto done;
+       }
+
        /* Set destination address and psm */
        bacpy(&bt_sk(sk)->dst, &la.l2_bdaddr);
        l2cap_pi(sk)->psm = la.l2_psm;