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authorLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2023-02-02 01:01:11 +0300
committerLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2023-02-10 01:18:48 +0300
commitdf5703348813235874d851934e957c3723d71644 (patch)
treeaa8217ebec403131c1524a365c6ac6e70fe71302 /net/bluetooth
parent2394186a2cefb9a45a029281a55749804dd8c556 (diff)
downloadlinux-df5703348813235874d851934e957c3723d71644.tar.xz
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>
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/l2cap_core.c24
-rw-r--r--net/bluetooth/l2cap_sock.c8
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;