Bluetooth: Fix bug with ERTM vars increment

All ERTM operations regarding the txWindow should be modulo 64,
otherwise we confuse the ERTM logic and connections will break.

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, 4 insertions, 3 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 7e39d9ee0b9c..a9fdfe401f5b 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3748,7 +3748,7 @@ static void l2cap_check_srej_gap(struct sock *sk, u8 tx_seq)
                 l2cap_ertm_reassembly_sdu(sk, skb, control);
                 l2cap_pi(sk)->buffer_seq_srej =
                         (l2cap_pi(sk)->buffer_seq_srej + 1) % 64;
-                tx_seq++;
+                tx_seq = (tx_seq + 1) % 64;
         }
 }
 
@@ -3784,10 +3784,11 @@ static void l2cap_send_srejframe(struct sock *sk, u8 tx_seq)
                 l2cap_send_sframe(pi, control);
 
                 new = kzalloc(sizeof(struct srej_list), GFP_ATOMIC);
-                new->tx_seq = pi->expected_tx_seq++;
+                new->tx_seq = pi->expected_tx_seq;
+                pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
                 list_add_tail(&new->list, SREJ_LIST(sk));
         }
-        pi->expected_tx_seq++;
+        pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
 }
 
 static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)