Bluetooth: Close L2CAP channel on invalid ReqSeq

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

1 files changed, 17 insertions, 1 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 478def700c7c..31514d8faa66 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3772,7 +3772,7 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
         struct sock *sk;
         struct l2cap_pinfo *pi;
         u16 control, len;
-        u8 tx_seq;
+        u8 tx_seq, req_seq, next_tx_seq_offset, req_seq_offset;
 
         sk = l2cap_get_chan_by_scid(&conn->chan_list, cid);
         if (!sk) {
@@ -3823,6 +3823,22 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
                 if (l2cap_check_fcs(pi, skb))
                         goto drop;
 
+                req_seq = __get_reqseq(control);
+                req_seq_offset = (req_seq - pi->expected_ack_seq) % 64;
+                if (req_seq_offset < 0)
+                        req_seq_offset += 64;
+
+                next_tx_seq_offset =
+                        (pi->next_tx_seq - pi->expected_ack_seq) % 64;
+                if (next_tx_seq_offset < 0)
+                        next_tx_seq_offset += 64;
+
+                /* check for invalid req-seq */
+                if (req_seq_offset > next_tx_seq_offset) {
+                        l2cap_send_disconn_req(pi->conn, sk);
+                        goto drop;
+                }
+
                 if (__is_iframe(control)) {
                         if (len < 4)
                                 goto drop;