diff options
| author | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2023-02-01 14:01:11 -0800 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2023-02-09 14:18:48 -0800 |
| commit | df5703348813235874d851934e957c3723d71644 (patch) | |
| tree | aa8217ebec403131c1524a365c6ac6e70fe71302 | |
| parent | 2394186a2cefb9a45a029281a55749804dd8c556 (diff) | |
Bluetooth: L2CAP: Fix potential user-after-free
This fixes all instances of which requires to allocate a buffer calling
alloc_skb which may release the chan lock and reacquire later which
makes it possible that the chan is disconnected in the meantime.
Fixes: a6a5568c03c4 ("Bluetooth: Lock the L2CAP channel when sending")
Reported-by: Alexander Coffin <alex.coffin@matician.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
| -rw-r--r-- | net/bluetooth/l2cap_core.c | 24 | ||||
| -rw-r--r-- | net/bluetooth/l2cap_sock.c | 8 |
2 files changed, 8 insertions, 24 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index a3e0dc6a6e73..adfc3ea06d08 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -2683,14 +2683,6 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len) if (IS_ERR(skb)) return PTR_ERR(skb); - /* Channel lock is released before requesting new skb and then - * reacquired thus we need to recheck channel state. - */ - if (chan->state != BT_CONNECTED) { - kfree_skb(skb); - return -ENOTCONN; - } - l2cap_do_send(chan, skb); return len; } @@ -2735,14 +2727,6 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len) if (IS_ERR(skb)) return PTR_ERR(skb); - /* Channel lock is released before requesting new skb and then - * reacquired thus we need to recheck channel state. - */ - if (chan->state != BT_CONNECTED) { - kfree_skb(skb); - return -ENOTCONN; - } - l2cap_do_send(chan, skb); err = len; break; @@ -2763,14 +2747,6 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len) */ err = l2cap_segment_sdu(chan, &seg_queue, msg, len); - /* The channel could have been closed while segmenting, - * check that it is still connected. - */ - if (chan->state != BT_CONNECTED) { - __skb_queue_purge(&seg_queue); - err = -ENOTCONN; - } - if (err) break; diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index ca8f07f3542b..eebe256104bc 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1624,6 +1624,14 @@ static struct sk_buff *l2cap_sock_alloc_skb_cb(struct l2cap_chan *chan, if (!skb) return ERR_PTR(err); + /* Channel lock is released before requesting new skb and then + * reacquired thus we need to recheck channel state. + */ + if (chan->state != BT_CONNECTED) { + kfree_skb(skb); + return ERR_PTR(-ENOTCONN); + } + skb->priority = sk->sk_priority; bt_cb(skb)->l2cap.chan = chan; |