Bluetooth: Fix issue with RFCOMM getsockopt operation
The commit 94a86df010 seem to have
uncovered a long standing bug that did not trigger so far.
BUG: unable to handle kernel paging request at 00000009dd503502
IP: [<ffffffff815b1868>] rfcomm_sock_getsockopt+0x128/0x200
PGD 0
Oops: 0000 [#1] SMP
Modules linked in: ath5k ath mac80211 cfg80211
CPU: 2 PID: 1459 Comm: bluetoothd Not tainted 3.11.0-133163-gcebd830 #2
Hardware name: System manufacturer System Product Name/P6T DELUXE V2, BIOS
1202 12/22/2010
task: ffff8803304106a0 ti: ffff88033046a000 task.ti: ffff88033046a000
RIP: 0010:[<ffffffff815b1868>] [<ffffffff815b1868>]
rfcomm_sock_getsockopt+0x128/0x200
RSP: 0018:ffff88033046bed8 EFLAGS: 00010246
RAX: 00000009dd503502 RBX: 0000000000000003 RCX: 00007fffa2ed5548
RDX: 0000000000000003 RSI: 0000000000000012 RDI: ffff88032fd37480
RBP: ffff88033046bf28 R08: 00007fffa2ed554c R09: ffff88032f5707d8
R10: 00007fffa2ed5548 R11: 0000000000000202 R12: ffff880330bbd000
R13: 00007fffa2ed5548 R14: 0000000000000003 R15: 00007fffa2ed554c
FS: 00007fc44cfac700(0000) GS:ffff88033fc80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000009dd503502 CR3: 00000003304c2000 CR4: 00000000000007e0
Stack:
ffff88033046bf28 ffffffff815b0f2f ffff88033046bf18 0002ffff81105ef6
0000000600000000 ffff88032fd37480 0000000000000012 00007fffa2ed5548
0000000000000003 00007fffa2ed554c ffff88033046bf78 ffffffff814c0380
Call Trace:
[<ffffffff815b0f2f>] ? rfcomm_sock_setsockopt+0x5f/0x190
[<ffffffff814c0380>] SyS_getsockopt+0x60/0xb0
[<ffffffff815e0852>] system_call_fastpath+0x16/0x1b
Code: 02 00 00 00 0f 47 d0 4c 89 ef e8 74 13 cd ff 83 f8 01 19 c9 f7 d1 83 e1
f2 e9 4b ff ff ff 0f 1f 44 00 00 49 8b 84 24 70 02 00 00 <4c> 8b 30 4c 89 c0 e8
2d 19 cd ff 85 c0 49 89 d7 b9 f2 ff ff ff
RIP [<ffffffff815b1868>] rfcomm_sock_getsockopt+0x128/0x200
RSP <ffff88033046bed8>
CR2: 00000009dd503502
It triggers in the following segment of the code:
0x1313 is in rfcomm_sock_getsockopt (net/bluetooth/rfcomm/sock.c:743).
738
739 static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __user *optval, int __user *optlen)
740 {
741 struct sock *sk = sock->sk;
742 struct rfcomm_conninfo cinfo;
743 struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
744 int len, err = 0;
745 u32 opt;
746
747 BT_DBG("sk %p", sk);
The l2cap_pi(sk) is wrong here since it should have been rfcomm_pi(sk),
but that socket of course does not contain the low-level connection
details requested here.
Tracking down the actual offending commit, it seems that this has been
introduced when doing some L2CAP refactoring:
commit 8c1d787be4
Author: Gustavo F. Padovan <padovan@profusion.mobi>
Date: Wed Apr 13 20:23:55 2011 -0300
@@ -743,6 +743,7 @@ static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __u
struct sock *sk = sock->sk;
struct sock *l2cap_sk;
struct rfcomm_conninfo cinfo;
+ struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
int len, err = 0;
u32 opt;
@@ -787,8 +788,8 @@ static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __u
l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;
- cinfo.hci_handle = l2cap_pi(l2cap_sk)->conn->hcon->handle;
- memcpy(cinfo.dev_class, l2cap_pi(l2cap_sk)->conn->hcon->dev_class, 3);
+ cinfo.hci_handle = conn->hcon->handle;
+ memcpy(cinfo.dev_class, conn->hcon->dev_class, 3);
The l2cap_sk got accidentally mixed into the sk (which is RFCOMM) and
now causing a problem within getsocketopt() system call. To fix this,
just re-introduce l2cap_sk and make sure the right socket is used for
the low-level connection details.
Reported-by: Fabio Rossi <rossi.f@inwind.it>
Reported-by: Janusz Dziedzic <janusz.dziedzic@gmail.com>
Tested-by: Janusz Dziedzic <janusz.dziedzic@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
60c7a3c9c7