Bluetooth: Fix SREJ_QUEUE corruption in L2CAP

Since all TxSeq values are modulo, we shall not compare them directly. We
have to compare their offset inside the TxWindow instead.

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, 12 insertions, 1 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 69f098d98141..b89762134e4e 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3394,6 +3394,8 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct sock *sk)
 static int l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_seq, u8 sar)
 {
         struct sk_buff *next_skb;
+        struct l2cap_pinfo *pi = l2cap_pi(sk);
+        int tx_seq_offset, next_tx_seq_offset;
 
         bt_cb(skb)->tx_seq = tx_seq;
         bt_cb(skb)->sar = sar;
@@ -3404,11 +3406,20 @@ static int l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_s
                 return 0;
         }
 
+        tx_seq_offset = (tx_seq - pi->buffer_seq) % 64;
+        if (tx_seq_offset < 0)
+                tx_seq_offset += 64;
+
         do {
                 if (bt_cb(next_skb)->tx_seq == tx_seq)
                         return -EINVAL;
 
-                if (bt_cb(next_skb)->tx_seq > tx_seq) {
+                next_tx_seq_offset = (bt_cb(next_skb)->tx_seq -
+                                                pi->buffer_seq) % 64;
+                if (next_tx_seq_offset < 0)
+                        next_tx_seq_offset += 64;
+
+                if (next_tx_seq_offset > tx_seq_offset) {
                         __skb_queue_before(SREJ_QUEUE(sk), next_skb, skb);
                         return 0;
                 }