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pvVudentz
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Bluetooth: ISO: fix iso_conn related locking and validity issues
sk->sk_state indicates whether iso_pi(sk)->conn is valid. Operations that check/update sk_state and access conn should hold lock_sock, otherwise they can race. The order of taking locks is hci_dev_lock > lock_sock > iso_conn_lock, which is how it is in connect/disconnect_cfm -> iso_conn_del -> iso_chan_del. Fix locking in iso_connect_cis/bis and sendmsg/recvmsg to take lock_sock around updating sk_state and conn. iso_conn_del must not occur during iso_connect_cis/bis, as it frees the iso_conn. Hold hdev->lock longer to prevent that. This should not reintroduce the issue fixed in commit 241f519 ("Bluetooth: ISO: Avoid circular locking dependency"), since the we acquire locks in order. We retain the fix in iso_sock_connect to release lock_sock before iso_connect_* acquires hdev->lock. Similarly for commit 6a5ad25 ("Bluetooth: ISO: Fix possible circular locking dependency"). We retain the fix in iso_conn_ready to not acquire iso_conn_lock before lock_sock. iso_conn_add shall return iso_conn with valid hcon. Make it so also when reusing an old CIS connection waiting for disconnect timeout (see __iso_sock_close where conn->hcon is set to NULL). Trace with iso_conn_del after iso_chan_add in iso_connect_cis: =============================================================== iso_sock_create:771: sock 00000000be9b69b7 iso_sock_init:693: sk 000000004dff667e iso_sock_bind:827: sk 000000004dff667e 70:1a:b8:98:ff:a2 type 1 iso_sock_setsockopt:1289: sk 000000004dff667e iso_sock_setsockopt:1289: sk 000000004dff667e iso_sock_setsockopt:1289: sk 000000004dff667e iso_sock_connect:875: sk 000000004dff667e iso_connect_cis:353: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da hci_get_route:1199: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da hci_conn_add:1005: hci0 dst 28:3d:c2:4a:7e:da iso_conn_add:140: hcon 000000007b65d182 conn 00000000daf8625e __iso_chan_add:214: conn 00000000daf8625e iso_connect_cfm:1700: hcon 000000007b65d182 bdaddr 28:3d:c2:4a:7e:da status 12 iso_conn_del:187: hcon 000000007b65d182 conn 00000000daf8625e, err 16 iso_sock_clear_timer:117: sock 000000004dff667e state 3 <Note: sk_state is BT_BOUND (3), so iso_connect_cis is still running at this point> iso_chan_del:153: sk 000000004dff667e, conn 00000000daf8625e, err 16 hci_conn_del:1151: hci0 hcon 000000007b65d182 handle 65535 hci_conn_unlink:1102: hci0: hcon 000000007b65d182 hci_chan_list_flush:2780: hcon 000000007b65d182 iso_sock_getsockopt:1376: sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_getsockopt:1376: sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_shutdown:1434: sock 00000000be9b69b7, sk 000000004dff667e, how 1 __iso_sock_close:632: sk 000000004dff667e state 5 socket 00000000be9b69b7 <Note: sk_state is BT_CONNECT (5), even though iso_chan_del sets BT_CLOSED (6). Only iso_connect_cis sets it to BT_CONNECT, so it must be that iso_chan_del occurred between iso_chan_add and end of iso_connect_cis.> BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 8000000006467067 P4D 8000000006467067 PUD 3f5f067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 RIP: 0010:__iso_sock_close (net/bluetooth/iso.c:664) bluetooth =============================================================== Trace with iso_conn_del before iso_chan_add in iso_connect_cis: =============================================================== iso_connect_cis:356: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da ... iso_conn_add:140: hcon 0000000093bc551f conn 00000000768ae504 hci_dev_put:1487: hci0 orig refcnt 21 hci_event_packet:7607: hci0: event 0x0e hci_cmd_complete_evt:4231: hci0: opcode 0x2062 hci_cc_le_set_cig_params:3846: hci0: status 0x07 hci_sent_cmd_data:3107: hci0 opcode 0x2062 iso_connect_cfm:1703: hcon 0000000093bc551f bdaddr 28:3d:c2:4a:7e:da status 7 iso_conn_del:187: hcon 0000000093bc551f conn 00000000768ae504, err 12 hci_conn_del:1151: hci0 hcon 0000000093bc551f handle 65535 hci_conn_unlink:1102: hci0: hcon 0000000093bc551f hci_chan_list_flush:2780: hcon 0000000093bc551f __iso_chan_add:214: conn 00000000768ae504 <Note: this conn was already freed in iso_conn_del above> iso_sock_clear_timer:117: sock 0000000098323f95 state 3 general protection fault, probably for non-canonical address 0x30b29c630930aec8: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 1920 Comm: bluetoothd Tainted: G E 6.3.0-rc7+ #4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 RIP: 0010:detach_if_pending+0x28/0xd0 Code: 90 90 0f 1f 44 00 00 48 8b 47 08 48 85 c0 0f 84 ad 00 00 00 55 89 d5 53 48 83 3f 00 48 89 fb 74 7d 66 90 48 8b 03 48 8b 53 08 <> RSP: 0018:ffffb90841a67d08 EFLAGS: 00010007 RAX: 0000000000000000 RBX: ffff9141bd5061b8 RCX: 0000000000000000 RDX: 30b29c630930aec8 RSI: ffff9141fdd21e80 RDI: ffff9141bd5061b8 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffb90841a67b88 R10: 0000000000000003 R11: ffffffff8613f558 R12: ffff9141fdd21e80 R13: 0000000000000000 R14: ffff9141b5976010 R15: ffff914185755338 FS: 00007f45768bd840(0000) GS:ffff9141fdd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000619000424074 CR3: 0000000009f5e005 CR4: 0000000000170ee0 Call Trace: <TASK> timer_delete+0x48/0x80 try_to_grab_pending+0xdf/0x170 __cancel_work+0x37/0xb0 iso_connect_cis+0x141/0x400 [bluetooth] =============================================================== Trace with NULL conn->hcon in state BT_CONNECT: =============================================================== __iso_sock_close:619: sk 00000000f7c71fc5 state 1 socket 00000000d90c5fe5 ... __iso_sock_close:619: sk 00000000f7c71fc5 state 8 socket 00000000d90c5fe5 iso_chan_del:153: sk 00000000f7c71fc5, conn 0000000022c03a7e, err 104 ... iso_sock_connect:862: sk 00000000129b56c3 iso_connect_cis:348: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7d:2a hci_get_route:1199: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7d:2a hci_dev_hold:1495: hci0 orig refcnt 19 __iso_chan_add:214: conn 0000000022c03a7e <Note: reusing old conn> iso_sock_clear_timer:117: sock 00000000129b56c3 state 3 ... iso_sock_ready:1485: sk 00000000129b56c3 ... iso_sock_sendmsg:1077: sock 00000000e5013966, sk 00000000129b56c3 BUG: kernel NULL pointer dereference, address: 00000000000006a8 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 1403 Comm: wireplumber Tainted: G E 6.3.0-rc7+ #4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 RIP: 0010:iso_sock_sendmsg+0x63/0x2a0 [bluetooth] =============================================================== Fixes: 241f519 ("Bluetooth: ISO: Avoid circular locking dependency") Fixes: 6a5ad25 ("Bluetooth: ISO: Fix possible circular locking dependency") Signed-off-by: Pauli Virtanen <[email protected]> Signed-off-by: Luiz Augusto von Dentz <[email protected]>
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‎net/bluetooth/iso.c

+31-22
Original file line numberDiff line numberDiff line change
@@ -123,8 +123,11 @@ static struct iso_conn *iso_conn_add(struct hci_conn *hcon)
123123
{
124124
struct iso_conn *conn = hcon->iso_data;
125125

126-
if (conn)
126+
if (conn) {
127+
if (!conn->hcon)
128+
conn->hcon = hcon;
127129
return conn;
130+
}
128131

129132
conn = kzalloc(sizeof(*conn), GFP_KERNEL);
130133
if (!conn)
@@ -300,14 +303,13 @@ static int iso_connect_bis(struct sock *sk)
300303
goto unlock;
301304
}
302305

303-
hci_dev_unlock(hdev);
304-
hci_dev_put(hdev);
306+
lock_sock(sk);
305307

306308
err = iso_chan_add(conn, sk, NULL);
307-
if (err)
308-
return err;
309-
310-
lock_sock(sk);
309+
if (err) {
310+
release_sock(sk);
311+
goto unlock;
312+
}
311313

312314
/* Update source addr of the socket */
313315
bacpy(&iso_pi(sk)->src, &hcon->src);
@@ -321,7 +323,6 @@ static int iso_connect_bis(struct sock *sk)
321323
}
322324

323325
release_sock(sk);
324-
return err;
325326

326327
unlock:
327328
hci_dev_unlock(hdev);
@@ -389,14 +390,13 @@ static int iso_connect_cis(struct sock *sk)
389390
goto unlock;
390391
}
391392

392-
hci_dev_unlock(hdev);
393-
hci_dev_put(hdev);
393+
lock_sock(sk);
394394

395395
err = iso_chan_add(conn, sk, NULL);
396-
if (err)
397-
return err;
398-
399-
lock_sock(sk);
396+
if (err) {
397+
release_sock(sk);
398+
goto unlock;
399+
}
400400

401401
/* Update source addr of the socket */
402402
bacpy(&iso_pi(sk)->src, &hcon->src);
@@ -413,7 +413,6 @@ static int iso_connect_cis(struct sock *sk)
413413
}
414414

415415
release_sock(sk);
416-
return err;
417416

418417
unlock:
419418
hci_dev_unlock(hdev);
@@ -1072,8 +1071,8 @@ static int iso_sock_sendmsg(struct socket *sock, struct msghdr *msg,
10721071
size_t len)
10731072
{
10741073
struct sock *sk = sock->sk;
1075-
struct iso_conn *conn = iso_pi(sk)->conn;
10761074
struct sk_buff *skb, **frag;
1075+
size_t mtu;
10771076
int err;
10781077

10791078
BT_DBG("sock %p, sk %p", sock, sk);
@@ -1085,11 +1084,18 @@ static int iso_sock_sendmsg(struct socket *sock, struct msghdr *msg,
10851084
if (msg->msg_flags & MSG_OOB)
10861085
return -EOPNOTSUPP;
10871086

1088-
if (sk->sk_state != BT_CONNECTED)
1087+
lock_sock(sk);
1088+
1089+
if (sk->sk_state != BT_CONNECTED) {
1090+
release_sock(sk);
10891091
return -ENOTCONN;
1092+
}
1093+
1094+
mtu = iso_pi(sk)->conn->hcon->hdev->iso_mtu;
1095+
1096+
release_sock(sk);
10901097

1091-
skb = bt_skb_sendmsg(sk, msg, len, conn->hcon->hdev->iso_mtu,
1092-
HCI_ISO_DATA_HDR_SIZE, 0);
1098+
skb = bt_skb_sendmsg(sk, msg, len, mtu, HCI_ISO_DATA_HDR_SIZE, 0);
10931099
if (IS_ERR(skb))
10941100
return PTR_ERR(skb);
10951101

@@ -1102,8 +1108,7 @@ static int iso_sock_sendmsg(struct socket *sock, struct msghdr *msg,
11021108
while (len) {
11031109
struct sk_buff *tmp;
11041110

1105-
tmp = bt_skb_sendmsg(sk, msg, len, conn->hcon->hdev->iso_mtu,
1106-
0, 0);
1111+
tmp = bt_skb_sendmsg(sk, msg, len, mtu, 0, 0);
11071112
if (IS_ERR(tmp)) {
11081113
kfree_skb(skb);
11091114
return PTR_ERR(tmp);
@@ -1158,15 +1163,19 @@ static int iso_sock_recvmsg(struct socket *sock, struct msghdr *msg,
11581163
BT_DBG("sk %p", sk);
11591164

11601165
if (test_and_clear_bit(BT_SK_DEFER_SETUP, &bt_sk(sk)->flags)) {
1166+
lock_sock(sk);
11611167
switch (sk->sk_state) {
11621168
case BT_CONNECT2:
1163-
lock_sock(sk);
11641169
iso_conn_defer_accept(pi->conn->hcon);
11651170
sk->sk_state = BT_CONFIG;
11661171
release_sock(sk);
11671172
return 0;
11681173
case BT_CONNECT:
1174+
release_sock(sk);
11691175
return iso_connect_cis(sk);
1176+
default:
1177+
release_sock(sk);
1178+
break;
11701179
}
11711180
}
11721181

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