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authorYichen Zhao <zhaoyichen@google.com>2015-12-01 11:11:01 -0800
committerMarcel Holtmann <marcel@holtmann.org>2015-12-10 00:51:51 +0100
commit1a11ec89dba7bcfb1cb502fc5945533f317ddd03 (patch)
tree2dd254b134295bb3638a5c69c3829f1607ea88a0
parentBluetooth: Don't treat connection timeout as a failure (diff)
downloadlinux-dev-1a11ec89dba7bcfb1cb502fc5945533f317ddd03.tar.xz
linux-dev-1a11ec89dba7bcfb1cb502fc5945533f317ddd03.zip
Bluetooth: Fix locking in bt_accept_dequeue after disconnection
Fix a crash that may happen when bt_accept_dequeue is run after a Bluetooth connection has been disconnected. bt_accept_unlink was called after release_sock, permitting bt_accept_unlink to run twice on the same socket and cause a NULL pointer dereference. [50510.241632] BUG: unable to handle kernel NULL pointer dereference at 00000000000001a8 [50510.241694] IP: [<ffffffffc01243f7>] bt_accept_unlink+0x47/0xa0 [bluetooth] [50510.241759] PGD 0 [50510.241776] Oops: 0002 [#1] SMP [50510.241802] Modules linked in: rtl8192cu rtl_usb rtlwifi rtl8192c_common 8021q garp stp mrp llc rfcomm bnep nls_iso8859_1 intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp arc4 ath9k ath9k_common ath9k_hw ath kvm eeepc_wmi asus_wmi mac80211 snd_hda_codec_hdmi snd_hda_codec_realtek sparse_keymap crct10dif_pclmul snd_hda_codec_generic crc32_pclmul snd_hda_intel snd_hda_controller cfg80211 snd_hda_codec i915 snd_hwdep snd_pcm ghash_clmulni_intel snd_timer snd soundcore serio_raw cryptd drm_kms_helper drm i2c_algo_bit shpchp ath3k mei_me lpc_ich btusb bluetooth 6lowpan_iphc mei lp parport wmi video mac_hid psmouse ahci libahci r8169 mii [50510.242279] CPU: 0 PID: 934 Comm: krfcommd Not tainted 3.16.0-49-generic #65~14.04.1-Ubuntu [50510.242327] Hardware name: ASUSTeK Computer INC. VM40B/VM40B, BIOS 1501 12/09/2014 [50510.242370] task: ffff8800d9068a30 ti: ffff8800d7a54000 task.ti: ffff8800d7a54000 [50510.242413] RIP: 0010:[<ffffffffc01243f7>] [<ffffffffc01243f7>] bt_accept_unlink+0x47/0xa0 [bluetooth] [50510.242480] RSP: 0018:ffff8800d7a57d58 EFLAGS: 00010246 [50510.242511] RAX: 0000000000000000 RBX: ffff880119bb8c00 RCX: ffff880119bb8eb0 [50510.242552] RDX: ffff880119bb8eb0 RSI: 00000000fffffe01 RDI: ffff880119bb8c00 [50510.242592] RBP: ffff8800d7a57d60 R08: 0000000000000283 R09: 0000000000000001 [50510.242633] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800d8da9eb0 [50510.242673] R13: ffff8800d74fdb80 R14: ffff880119bb8c00 R15: ffff8800d8da9c00 [50510.242715] FS: 0000000000000000(0000) GS:ffff88011fa00000(0000) knlGS:0000000000000000 [50510.242761] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [50510.242794] CR2: 00000000000001a8 CR3: 0000000001c13000 CR4: 00000000001407f0 [50510.242835] Stack: [50510.242849] ffff880119bb8eb0 ffff8800d7a57da0 ffffffffc0124506 ffff8800d8da9eb0 [50510.242899] ffff8800d8da9c00 ffff8800d9068a30 0000000000000000 ffff8800d74fdb80 [50510.242949] ffff8800d6f85208 ffff8800d7a57e08 ffffffffc0159985 000000000000001f [50510.242999] Call Trace: [50510.243027] [<ffffffffc0124506>] bt_accept_dequeue+0xb6/0x180 [bluetooth] [50510.243085] [<ffffffffc0159985>] l2cap_sock_accept+0x125/0x220 [bluetooth] [50510.243128] [<ffffffff810a1b30>] ? wake_up_state+0x20/0x20 [50510.243163] [<ffffffff8164946e>] kernel_accept+0x4e/0xa0 [50510.243200] [<ffffffffc05b97cd>] rfcomm_run+0x1ad/0x890 [rfcomm] [50510.243238] [<ffffffffc05b9620>] ? rfcomm_process_rx+0x8a0/0x8a0 [rfcomm] [50510.243281] [<ffffffff81091572>] kthread+0xd2/0xf0 [50510.243312] [<ffffffff810914a0>] ? kthread_create_on_node+0x1c0/0x1c0 [50510.243353] [<ffffffff8176e9d8>] ret_from_fork+0x58/0x90 [50510.243387] [<ffffffff810914a0>] ? kthread_create_on_node+0x1c0/0x1c0 [50510.243424] Code: 00 48 8b 93 b8 02 00 00 48 8d 83 b0 02 00 00 48 89 51 08 48 89 0a 48 89 83 b0 02 00 00 48 89 83 b8 02 00 00 48 8b 83 c0 02 00 00 <66> 83 a8 a8 01 00 00 01 48 c7 83 c0 02 00 00 00 00 00 00 f0 ff [50510.243685] RIP [<ffffffffc01243f7>] bt_accept_unlink+0x47/0xa0 [bluetooth] [50510.243737] RSP <ffff8800d7a57d58> [50510.243758] CR2: 00000000000001a8 [50510.249457] ---[ end trace bb984f932c4e3ab3 ]--- Signed-off-by: Yichen Zhao <zhaoyichen@google.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
-rw-r--r--net/bluetooth/af_bluetooth.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index 5785e8e6400e..cb4e8d4f7c25 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -186,8 +186,8 @@ struct sock *bt_accept_dequeue(struct sock *parent, struct socket *newsock)
/* FIXME: Is this check still needed */
if (sk->sk_state == BT_CLOSED) {
- release_sock(sk);
bt_accept_unlink(sk);
+ release_sock(sk);
continue;
}