Bluetooth: Completes the I-frame tx_seq check logic on RECV

Add checks for invalid tx_seq and fixes the duplicated tx_seq check.

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, 36 insertions, 4 deletions

diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index cfd672419315..481cec22ef96 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -3302,7 +3302,7 @@ static inline void l2cap_send_i_or_rr_or_rnr(struct sock *sk)
         }
 }
 
-static void l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_seq, u8 sar)
+static int l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_seq, u8 sar)
 {
         struct sk_buff *next_skb;
 
@@ -3312,13 +3312,16 @@ static void l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_
         next_skb = skb_peek(SREJ_QUEUE(sk));
         if (!next_skb) {
                 __skb_queue_tail(SREJ_QUEUE(sk), skb);
-                return;
+                return 0;
         }
 
         do {
+                if (bt_cb(next_skb)->tx_seq == tx_seq)
+                        return -EINVAL;
+
                 if (bt_cb(next_skb)->tx_seq > tx_seq) {
                         __skb_queue_before(SREJ_QUEUE(sk), next_skb, skb);
-                        return;
+                        return 0;
                 }
 
                 if (skb_queue_is_last(SREJ_QUEUE(sk), next_skb))
@@ -3327,6 +3330,8 @@ static void l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_
         } while ((next_skb = skb_queue_next(SREJ_QUEUE(sk), next_skb)));
 
         __skb_queue_tail(SREJ_QUEUE(sk), skb);
+
+        return 0;
 }
 
 static int l2cap_ertm_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 control)
@@ -3579,6 +3584,7 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
         u8 tx_seq = __get_txseq(rx_control);
         u8 req_seq = __get_reqseq(rx_control);
         u8 sar = rx_control >> L2CAP_CTRL_SAR_SHIFT;
+        u8 tx_seq_offset, expected_tx_seq_offset;
         int num_to_ack = (pi->tx_win/6) + 1;
         int err = 0;
 
@@ -3598,6 +3604,16 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
         if (tx_seq == pi->expected_tx_seq)
                 goto expected;
 
+        tx_seq_offset = (tx_seq - pi->buffer_seq) % 64;
+        if (tx_seq_offset < 0)
+                tx_seq_offset += 64;
+
+        /* invalid tx_seq */
+        if (tx_seq_offset >= pi->tx_win) {
+                l2cap_send_disconn_req(pi->conn, sk);
+                goto drop;
+        }
+
         if (pi->conn_state & L2CAP_CONN_SREJ_SENT) {
                 struct srej_list *first;
 
@@ -3617,7 +3633,10 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
                         }
                 } else {
                         struct srej_list *l;
-                        l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
+
+                        /* duplicated tx_seq */
+                        if (l2cap_add_to_srej_queue(sk, skb, tx_seq, sar) < 0)
+                                goto drop;
 
                         list_for_each_entry(l, SREJ_LIST(sk), list) {
                                 if (l->tx_seq == tx_seq) {
@@ -3628,6 +3647,15 @@ static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, str
                         l2cap_send_srejframe(sk, tx_seq);
                 }
         } else {
+                expected_tx_seq_offset =
+                        (pi->expected_tx_seq - pi->buffer_seq) % 64;
+                if (expected_tx_seq_offset < 0)
+                        expected_tx_seq_offset += 64;
+
+                /* duplicated tx_seq */
+                if (tx_seq_offset < expected_tx_seq_offset)
+                        goto drop;
+
                 pi->conn_state |= L2CAP_CONN_SREJ_SENT;
 
                 INIT_LIST_HEAD(SREJ_LIST(sk));
@@ -3676,6 +3704,10 @@ expected:
                 l2cap_send_ack(pi);
 
         return 0;
+
+drop:
+        kfree_skb(skb);
+        return 0;
 }
 
 static inline void l2cap_data_channel_rrframe(struct sock *sk, u16 rx_control)