diff options
| author | Andrei Emeltchenko | 2010-11-03 12:32:44 +0200 |
|---|---|---|
| committer | Gustavo F. Padovan | 2010-12-01 21:04:36 -0200 |
| commit | a49184c229535ebedbb659214db2d4d1d77b7c07 (patch) | |
| tree | 6a06bba4cf178a45d2f1ad61d91c4e3adee46cd4 /net/bluetooth | |
| parent | d31dbf6e5989b2fd9a30ec5b25436e94f009d6df (diff) | |
Bluetooth: Check sk is not owned before freeing l2cap_conn
Check that socket sk is not locked in user process before removing
l2cap connection handler.
lock_sock and release_sock do not hold a normal spinlock directly but
instead hold the owner field. This means bh_lock_sock can still execute
even if the socket is "locked". More info can be found here:
http://www.linuxfoundation.org/collaborate/workgroups/networking/socketlocks
krfcommd kernel thread may be preempted with l2cap tasklet which remove
l2cap_conn structure. If krfcommd is in process of sending of RFCOMM reply
(like "RFCOMM UA" reply to "RFCOMM DISC") then kernel crash happens.
...
[ 694.175933] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 694.184936] pgd = c0004000
[ 694.187683] [00000000] *pgd=00000000
[ 694.191711] Internal error: Oops: 5 [#1] PREEMPT
[ 694.196350] last sysfs file: /sys/devices/platform/hci_h4p/firmware/hci_h4p/loading
[ 694.260375] CPU: 0 Not tainted (2.6.32.10 #1)
[ 694.265106] PC is at l2cap_sock_sendmsg+0x43c/0x73c [l2cap]
[ 694.270721] LR is at 0xd7017303
...
[ 694.525085] Backtrace:
[ 694.527587] [<bf266be0>] (l2cap_sock_sendmsg+0x0/0x73c [l2cap]) from [<c02f2cc8>] (sock_sendmsg+0xb8/0xd8)
[ 694.537292] [<c02f2c10>] (sock_sendmsg+0x0/0xd8) from [<c02f3044>] (kernel_sendmsg+0x48/0x80)
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@nokia.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Diffstat (limited to 'net/bluetooth')
| -rw-r--r-- | net/bluetooth/l2cap.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c index cd8f6ea03841..4ed38272df78 100644 --- a/net/bluetooth/l2cap.c +++ b/net/bluetooth/l2cap.c @@ -3078,6 +3078,14 @@ static inline int l2cap_connect_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hd break; default: + /* don't delete l2cap channel if sk is owned by user */ + if (sock_owned_by_user(sk)) { + sk->sk_state = BT_DISCONN; + l2cap_sock_clear_timer(sk); + l2cap_sock_set_timer(sk, HZ / 5); + break; + } + l2cap_chan_del(sk, ECONNREFUSED); break; } @@ -3283,6 +3291,15 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd sk->sk_shutdown = SHUTDOWN_MASK; + /* don't delete l2cap channel if sk is owned by user */ + if (sock_owned_by_user(sk)) { + sk->sk_state = BT_DISCONN; + l2cap_sock_clear_timer(sk); + l2cap_sock_set_timer(sk, HZ / 5); + bh_unlock_sock(sk); + return 0; + } + l2cap_chan_del(sk, ECONNRESET); bh_unlock_sock(sk); @@ -3305,6 +3322,15 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd if (!sk) return 0; + /* don't delete l2cap channel if sk is owned by user */ + if (sock_owned_by_user(sk)) { + sk->sk_state = BT_DISCONN; + l2cap_sock_clear_timer(sk); + l2cap_sock_set_timer(sk, HZ / 5); + bh_unlock_sock(sk); + return 0; + } + l2cap_chan_del(sk, 0); bh_unlock_sock(sk); |