[Bluetooth] Restrict well known PSM to privileged users

The PSM values below 0x1001 of L2CAP are reserved for well known
services. Restrict the possibility to bind them to privileged
users.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index be5a6e60a3c4..f8c25d500155 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -585,6 +585,12 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_
                 goto done;
         }
 
+        if (la->l2_psm > 0 && btohs(la->l2_psm) < 0x1001 &&
+                                !capable(CAP_NET_BIND_SERVICE)) {
+                err = -EACCES;
+                goto done;
+        }
+                
         write_lock_bh(&l2cap_sk_list.lock);
 
         if (la->l2_psm && __l2cap_get_sock_by_addr(la->l2_psm, &la->l2_bdaddr)) {