| Message ID | 20221017075813.6071-1-shaozhengchao@huawei.com |
|---|---|
| State | Accepted |
| Commit | 0d0e2d032811280b927650ff3c15fe5020e82533 |
| Headers | show |
| Series | Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del() | expand |
This is automated email and please do not reply to this email! Dear submitter, Thank you for submitting the patches to the linux bluetooth mailing list. This is a CI test results with your patch series: PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=685728 ---Test result--- Test Summary: CheckPatch PASS 1.64 seconds GitLint PASS 0.95 seconds SubjectPrefix PASS 0.86 seconds BuildKernel PASS 35.42 seconds BuildKernel32 PASS 31.82 seconds Incremental Build with patchesPASS 45.28 seconds TestRunner: Setup PASS 523.07 seconds TestRunner: l2cap-tester PASS 17.89 seconds TestRunner: iso-tester PASS 17.02 seconds TestRunner: bnep-tester PASS 6.84 seconds TestRunner: mgmt-tester PASS 109.11 seconds TestRunner: rfcomm-tester PASS 10.67 seconds TestRunner: sco-tester PASS 10.09 seconds TestRunner: ioctl-tester PASS 11.35 seconds TestRunner: mesh-tester PASS 8.29 seconds TestRunner: smp-tester PASS 10.07 seconds TestRunner: userchan-tester PASS 7.04 seconds --- Regards, Linux Bluetooth
Hello: This patch was applied to bluetooth/bluetooth-next.git (master) by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>: On Mon, 17 Oct 2022 15:58:13 +0800 you wrote: > When l2cap_recv_frame() is invoked to receive data, and the cid is > L2CAP_CID_A2MP, if the channel does not exist, it will create a channel. > However, after a channel is created, the hold operation of the channel > is not performed. In this case, the value of channel reference counting > is 1. As a result, after hci_error_reset() is triggered, l2cap_conn_del() > invokes the close hook function of A2MP to release the channel. Then > l2cap_chan_unlock(chan) will trigger UAF issue. > > [...] Here is the summary with links: - Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del() https://git.kernel.org/bluetooth/bluetooth-next/c/42cf46dea905 You are awesome, thank you!
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 2283871d3f01..9a32ce634919 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -7615,6 +7615,7 @@ static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid, return; } + l2cap_chan_hold(chan); l2cap_chan_lock(chan); } else { BT_DBG("unknown cid 0x%4.4x", cid);
When l2cap_recv_frame() is invoked to receive data, and the cid is L2CAP_CID_A2MP, if the channel does not exist, it will create a channel. However, after a channel is created, the hold operation of the channel is not performed. In this case, the value of channel reference counting is 1. As a result, after hci_error_reset() is triggered, l2cap_conn_del() invokes the close hook function of A2MP to release the channel. Then l2cap_chan_unlock(chan) will trigger UAF issue. The process is as follows: Receive data: l2cap_data_channel() a2mp_channel_create() --->channel ref is 2 l2cap_chan_put() --->channel ref is 1 Triger event: hci_error_reset() hci_dev_do_close() ... l2cap_disconn_cfm() l2cap_conn_del() l2cap_chan_hold() --->channel ref is 2 l2cap_chan_del() --->channel ref is 1 a2mp_chan_close_cb() --->channel ref is 0, release channel l2cap_chan_unlock() --->UAF of channel The detailed Call Trace is as follows: BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0xa6/0x5e0 Read of size 8 at addr ffff8880160664b8 by task kworker/u11:1/7593 Workqueue: hci0 hci_error_reset Call Trace: <TASK> dump_stack_lvl+0xcd/0x134 print_report.cold+0x2ba/0x719 kasan_report+0xb1/0x1e0 kasan_check_range+0x140/0x190 __mutex_unlock_slowpath+0xa6/0x5e0 l2cap_conn_del+0x404/0x7b0 l2cap_disconn_cfm+0x8c/0xc0 hci_conn_hash_flush+0x11f/0x260 hci_dev_close_sync+0x5f5/0x11f0 hci_dev_do_close+0x2d/0x70 hci_error_reset+0x9e/0x140 process_one_work+0x98a/0x1620 worker_thread+0x665/0x1080 kthread+0x2e4/0x3a0 ret_from_fork+0x1f/0x30 </TASK> Allocated by task 7593: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0xa9/0xd0 l2cap_chan_create+0x40/0x930 amp_mgr_create+0x96/0x990 a2mp_channel_create+0x7d/0x150 l2cap_recv_frame+0x51b8/0x9a70 l2cap_recv_acldata+0xaa3/0xc00 hci_rx_work+0x702/0x1220 process_one_work+0x98a/0x1620 worker_thread+0x665/0x1080 kthread+0x2e4/0x3a0 ret_from_fork+0x1f/0x30 Freed by task 7593: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_set_free_info+0x20/0x30 ____kasan_slab_free+0x167/0x1c0 slab_free_freelist_hook+0x89/0x1c0 kfree+0xe2/0x580 l2cap_chan_put+0x22a/0x2d0 l2cap_conn_del+0x3fc/0x7b0 l2cap_disconn_cfm+0x8c/0xc0 hci_conn_hash_flush+0x11f/0x260 hci_dev_close_sync+0x5f5/0x11f0 hci_dev_do_close+0x2d/0x70 hci_error_reset+0x9e/0x140 process_one_work+0x98a/0x1620 worker_thread+0x665/0x1080 kthread+0x2e4/0x3a0 ret_from_fork+0x1f/0x30 Last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0xbe/0xd0 call_rcu+0x99/0x740 netlink_release+0xe6a/0x1cf0 __sock_release+0xcd/0x280 sock_close+0x18/0x20 __fput+0x27c/0xa90 task_work_run+0xdd/0x1a0 exit_to_user_mode_prepare+0x23c/0x250 syscall_exit_to_user_mode+0x19/0x50 do_syscall_64+0x42/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Second to last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0xbe/0xd0 call_rcu+0x99/0x740 netlink_release+0xe6a/0x1cf0 __sock_release+0xcd/0x280 sock_close+0x18/0x20 __fput+0x27c/0xa90 task_work_run+0xdd/0x1a0 exit_to_user_mode_prepare+0x23c/0x250 syscall_exit_to_user_mode+0x19/0x50 do_syscall_64+0x42/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put") Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> --- net/bluetooth/l2cap_core.c | 1 + 1 file changed, 1 insertion(+)