7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye commit 1a572db43c057566771b485598ad2e66cb390821 upstream. The fragmented path in hci_queue_iso() calls __skb_queue_tail() without holding conn->data_q.lock. The socket lock serializes senders, but the transmit worker can concurrently remove packets from this queue using skb_dequeue(). After an insertion saves the old tail pointer, hci_sched_iso() can dequeue that packet and pass it to the driver. The driver can free the packet before the insertion resumes and writes to the old tail's next pointer, causing a use-after-free. Concurrent updates can also corrupt the queue. KASAN reported: BUG: KASAN: slab-use-after-free in hci_send_iso+0xc7d/0xe10 Call Trace: hci_send_iso+0xc7d/0xe10 iso_sock_sendmsg+0x710/0x900 __sys_sendto+0x34a/0x3a0 Allocated by task 86: __alloc_skb+0xdd/0x820 alloc_skb_with_frags+0x7e/0x770 sock_alloc_send_pskb+0x67a/0x820 bt_skb_sendmsg.constprop.0+0xc0/0x6c0 iso_sock_sendmsg+0x44e/0x900 Freed by task 90: kmem_cache_free+0xcb/0x3d0 vhci_read+0x33f/0x4d0 vfs_read+0x177/0xa20 Hold the queue lock across the entire fragment batch, as hci_queue_acl() does, to serialize insertion against dequeue while preserving fragment ordering. Fixes: 26afbd826ee3 ("Bluetooth: Add initial implementation of CIS connections") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/hci_core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3335,6 +3335,8 @@ static void hci_queue_iso(struct hci_con skb_shinfo(skb)->frag_list = NULL; + spin_lock_bh(&queue->lock); + __skb_queue_tail(queue, skb); do { @@ -3349,6 +3351,8 @@ static void hci_queue_iso(struct hci_con __skb_queue_tail(queue, skb); } while (list); + + spin_unlock_bh(&queue->lock); } bt_dev_dbg(hdev, "hcon %p queued %d", conn, skb_queue_len(queue));