Bluetooth: Check if SDU size is greater than MTU on L2CAP

After reassembly the SDU we need to check his size. It can't overflow
the MTU size.

Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index ac00f5fac2d2..2e354d29f102 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3277,15 +3277,19 @@ static int l2cap_sar_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 co
                 pi->conn_state &= ~L2CAP_CONN_SAR_SDU;
                 pi->partial_sdu_len += skb->len;
 
+                if (pi->partial_sdu_len > pi->imtu)
+                        goto drop;
+
                 if (pi->partial_sdu_len == pi->sdu_len) {
                         _skb = skb_clone(pi->sdu, GFP_ATOMIC);
                         err = sock_queue_rcv_skb(sk, _skb);
                         if (err < 0)
                                 kfree_skb(_skb);
                 }
-                kfree_skb(pi->sdu);
                 err = 0;
 
+drop:
+                kfree_skb(pi->sdu);
                 break;
         }