[PATCH 6.1 0558/1146] Bluetooth: hci_conn: Fix crash on hci_create_cis_sync

Greg Kroah-Hartman
2022-12-28T16:10:01Z

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit 50757a259ba78c4e938b5735e76ffec6cd0c942e ]

When attempting to connect multiple ISO sockets without using
DEFER_SETUP may result in the following crash:

BUG: KASAN: null-ptr-deref in hci_create_cis_sync+0x18b/0x2b0
Read of size 2 at addr 0000000000000036 by task kworker/u3:1/50

CPU: 0 PID: 50 Comm: kworker/u3:1 Not tainted
6.0.0-rc7-02243-gb84a13ff4eda #4373
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS 1.16.0-1.fc36 04/01/2014
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
<TASK>
dump_stack_lvl+0x19/0x27
kasan_report+0xbc/0xf0
? hci_create_cis_sync+0x18b/0x2b0
hci_create_cis_sync+0x18b/0x2b0
? get_link_mode+0xd0/0xd0
? __ww_mutex_lock_slowpath+0x10/0x10
? mutex_lock+0xe0/0xe0
? get_link_mode+0xd0/0xd0
hci_cmd_sync_work+0x111/0x190
process_one_work+0x427/0x650
worker_thread+0x87/0x750
? process_one_work+0x650/0x650
kthread+0x14e/0x180
? kthread_exit+0x50/0x50
ret_from_fork+0x22/0x30
</TASK>

Fixes: 26afbd826ee3 ("Bluetooth: Add initial implementation of CIS connections")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/hci_conn.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index a6c12863a253..8aab2e882958 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1881,7 +1881,7 @@ static int hci_create_cis_sync(struct hci_dev *hdev, void *data)
continue;

/* Check if all CIS(s) belonging to a CIG are ready */
- if (conn->link->state != BT_CONNECTED ||
+ if (!conn->link || conn->link->state != BT_CONNECTED ||
conn->state != BT_CONNECT) {
cmd.cp.num_cis = 0;
break;
--
2.35.1