From 60c7a3c9c77239d5a7430c42a2c796881716cca1 Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Sat, 2 Nov 2013 02:36:31 -0700 Subject: [PATCH] Bluetooth: Fix issue with RFCOMM getsockopt operation The commit 94a86df01082557e2de45865e538d7fb6c46231c seem to have uncovered a long standing bug that did not trigger so far. BUG: unable to handle kernel paging request at 00000009dd503502 IP: [] 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:[] [] 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: [] ? rfcomm_sock_setsockopt+0x5f/0x190 [] SyS_getsockopt+0x60/0xb0 [] 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 [] rfcomm_sock_getsockopt+0x128/0x200 RSP 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 8c1d787be4b62d2d1b6f04953eca4bcf7c839d44 Author: Gustavo F. Padovan 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 Reported-by: Janusz Dziedzic Tested-by: Janusz Dziedzic Signed-off-by: Marcel Holtmann Signed-off-by: Johan Hedberg --- net/bluetooth/rfcomm/sock.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index 30b3721dc6d7..7096cfe3bd5a 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -732,8 +732,9 @@ static int rfcomm_sock_setsockopt(struct socket *sock, int level, int optname, c static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __user *optval, int __user *optlen) { struct sock *sk = sock->sk; + struct sock *l2cap_sk; + struct l2cap_conn *conn; struct rfcomm_conninfo cinfo; - struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn; int len, err = 0; u32 opt; @@ -776,6 +777,9 @@ static int rfcomm_sock_getsockopt_old(struct socket *sock, int optname, char __u break; } + l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk; + conn = l2cap_pi(l2cap_sk)->chan->conn; + memset(&cinfo, 0, sizeof(cinfo)); cinfo.hci_handle = conn->hcon->handle; memcpy(cinfo.dev_class, conn->hcon->dev_class, 3); -- 2.20.1