Bluetooth: Check MTU value in l2cap_sock_setsockopt_old

If user tries to set an invalid MTU value, l2cap_sock_setsockopt_old
should return -EINVAL.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

1 files changed, 21 insertions, 0 deletions

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index d856cc8f22a3..ab5868d94307 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -445,6 +445,22 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname, ch
         return err;
 }
 
+static bool l2cap_valid_mtu(struct l2cap_chan *chan, u16 mtu)
+{
+        switch (chan->scid) {
+        case L2CAP_CID_LE_DATA:
+                if (mtu < L2CAP_LE_DEFAULT_MTU)
+                        return false;
+                break;
+
+        default:
+                if (mtu < L2CAP_DEFAULT_MIN_MTU)
+                        return false;
+        }
+
+        return true;
+}
+
 static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __user *optval, unsigned int optlen)
 {
         struct sock *sk = sock->sk;
@@ -483,6 +499,11 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __us
                         break;
                 }
 
+                if (!l2cap_valid_mtu(chan, opts.imtu)) {
+                        err = -EINVAL;
+                        break;
+                }
+
                 chan->mode = opts.mode;
                 switch (chan->mode) {
                 case L2CAP_MODE_BASIC: