From: Wang ShaoBo <redacted>
use-after-free error in lock_sock_nested is reported:
[ 179.140137][ T3731] =====================================================
[ 179.142675][ T3731] BUG: KMSAN: use-after-free in lock_sock_nested+0x280/0x2c0
[ 179.145494][ T3731] CPU: 4 PID: 3731 Comm: kworker/4:2 Not tainted 5.12.0-rc6+ #54
[ 179.148432][ T3731] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 179.151806][ T3731] Workqueue: events l2cap_chan_timeout
[ 179.152730][ T3731] Call Trace:
[ 179.153301][ T3731] dump_stack+0x24c/0x2e0
[ 179.154063][ T3731] kmsan_report+0xfb/0x1e0
[ 179.154855][ T3731] __msan_warning+0x5c/0xa0
[ 179.155579][ T3731] lock_sock_nested+0x280/0x2c0
[ 179.156436][ T3731] ? kmsan_get_metadata+0x116/0x180
[ 179.157257][ T3731] l2cap_sock_teardown_cb+0xb8/0x890
[ 179.158154][ T3731] ? __msan_metadata_ptr_for_load_8+0x10/0x20
[ 179.159141][ T3731] ? kmsan_get_metadata+0x116/0x180
[ 179.159994][ T3731] ? kmsan_get_shadow_origin_ptr+0x84/0xb0
[ 179.160959][ T3731] ? l2cap_sock_recv_cb+0x420/0x420
[ 179.161834][ T3731] l2cap_chan_del+0x3e1/0x1d50
[ 179.162608][ T3731] ? kmsan_get_metadata+0x116/0x180
[ 179.163435][ T3731] ? kmsan_get_shadow_origin_ptr+0x84/0xb0
[ 179.164406][ T3731] l2cap_chan_close+0xeea/0x1050
[ 179.165189][ T3731] ? kmsan_internal_unpoison_shadow+0x42/0x70
[ 179.166180][ T3731] l2cap_chan_timeout+0x1da/0x590
[ 179.167066][ T3731] ? __msan_metadata_ptr_for_load_8+0x10/0x20
[ 179.168023][ T3731] ? l2cap_chan_create+0x560/0x560
[ 179.168818][ T3731] process_one_work+0x121d/0x1ff0
[ 179.169598][ T3731] worker_thread+0x121b/0x2370
[ 179.170346][ T3731] kthread+0x4ef/0x610
[ 179.171010][ T3731] ? process_one_work+0x1ff0/0x1ff0
[ 179.171828][ T3731] ? kthread_blkcg+0x110/0x110
[ 179.172587][ T3731] ret_from_fork+0x1f/0x30
[ 179.173348][ T3731]
[ 179.173752][ T3731] Uninit was created at:
[ 179.174409][ T3731] kmsan_internal_poison_shadow+0x5c/0xf0
[ 179.175373][ T3731] kmsan_slab_free+0x76/0xc0
[ 179.176060][ T3731] kfree+0x3a5/0x1180
[ 179.176664][ T3731] __sk_destruct+0x8af/0xb80
[ 179.177375][ T3731] __sk_free+0x812/0x8c0
[ 179.178032][ T3731] sk_free+0x97/0x130
[ 179.178686][ T3731] l2cap_sock_release+0x3d5/0x4d0
[ 179.179457][ T3731] sock_close+0x150/0x450
[ 179.180117][ T3731] __fput+0x6bd/0xf00
[ 179.180787][ T3731] ____fput+0x37/0x40
[ 179.181481][ T3731] task_work_run+0x140/0x280
[ 179.182219][ T3731] do_exit+0xe51/0x3e60
[ 179.182930][ T3731] do_group_exit+0x20e/0x450
[ 179.183656][ T3731] get_signal+0x2dfb/0x38f0
[ 179.184344][ T3731] arch_do_signal_or_restart+0xaa/0xe10
[ 179.185266][ T3731] exit_to_user_mode_prepare+0x2d2/0x560
[ 179.186136][ T3731] syscall_exit_to_user_mode+0x35/0x60
[ 179.186984][ T3731] do_syscall_64+0xc5/0x140
[ 179.187681][ T3731] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 179.188604][ T3731] =====================================================
In our case, there are two Thread A and B:
Context: Thread A: Context: Thread B:
l2cap_chan_timeout() __se_sys_shutdown()
l2cap_chan_close() l2cap_sock_shutdown()
l2cap_chan_del() l2cap_chan_close()
l2cap_sock_teardown_cb() l2cap_sock_teardown_cb()
Once l2cap_sock_teardown_cb() excuted, this sock will be marked as SOCK_ZAPPED,
and can be treated as killable in l2cap_sock_kill() if sock_orphan() has
excuted, at this time we close sock through sock_close() which end to call
l2cap_sock_kill() like Thread C:
Context: Thread C:
sock_close()
l2cap_sock_release()
sock_orphan()
l2cap_sock_kill() #free sock if refcnt is 1
If C completed, Once A or B reaches l2cap_sock_teardown_cb() again,
use-after-free happened.
We should set chan->data to NULL if sock is destructed, for telling teardown
operation is not allowed in l2cap_sock_teardown_cb(), and also we should
avoid killing an already killed socket in l2cap_sock_close_cb().
Signed-off-by: Wang ShaoBo <redacted>
Signed-off-by: Luiz Augusto von Dentz <redacted>
---
net/bluetooth/l2cap_sock.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index c99d65ef13b1..160c016a5dfb 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1508,6 +1508,9 @@ static void l2cap_sock_close_cb(struct l2cap_chan *chan)
{
struct sock *sk = chan->data;
+ if (!sk)
+ return;
+
l2cap_sock_kill(sk);
}
@@ -1516,6 +1519,9 @@ static void l2cap_sock_teardown_cb(struct l2cap_chan *chan, int err)
struct sock *sk = chan->data;
struct sock *parent;
+ if (!sk)
+ return;
+
BT_DBG("chan %p state %s", chan, state_to_string(chan->state));
/* This callback can be called both for server (BT_LISTEN)@@ -1707,8 +1713,10 @@ static void l2cap_sock_destruct(struct sock *sk)
{
BT_DBG("sk %p", sk);
- if (l2cap_pi(sk)->chan)
+ if (l2cap_pi(sk)->chan) {
+ l2cap_pi(sk)->chan->data = NULL;
l2cap_chan_put(l2cap_pi(sk)->chan);
+ }
if (l2cap_pi(sk)->rx_busy_skb) {
kfree_skb(l2cap_pi(sk)->rx_busy_skb);--
2.31.1
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=540071
---Test result---
Test Summary:
CheckPatch FAIL 0.54 seconds
GitLint FAIL 0.13 seconds
BuildKernel PASS 599.16 seconds
TestRunner: Setup PASS 400.87 seconds
TestRunner: l2cap-tester PASS 3.02 seconds
TestRunner: bnep-tester PASS 2.10 seconds
TestRunner: mgmt-tester PASS 34.08 seconds
TestRunner: rfcomm-tester PASS 2.32 seconds
TestRunner: sco-tester PASS 2.28 seconds
TestRunner: smp-tester PASS 2.36 seconds
TestRunner: userchan-tester PASS 2.10 seconds
Details
##############################
Test: CheckPatch - FAIL - 0.54 seconds
Run checkpatch.pl script with rule in .checkpatch.conf
Bluetooth: fix use-after-free error in lock_sock_nested()
WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#70:
Once l2cap_sock_teardown_cb() excuted, this sock will be marked as SOCK_ZAPPED,
total: 0 errors, 1 warnings, 0 checks, 29 lines checked
NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.
"[PATCH] Bluetooth: fix use-after-free error in lock_sock_nested()" has style problems, please review.
NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
##############################
Test: GitLint - FAIL - 0.13 seconds
Run gitlint with rule in .gitlint
Bluetooth: fix use-after-free error in lock_sock_nested()
6: B1 Line exceeds max length (81>80): "[ 179.142675][ T3731] BUG: KMSAN: use-after-free in lock_sock_nested+0x280/0x2c0"
7: B1 Line exceeds max length (85>80): "[ 179.145494][ T3731] CPU: 4 PID: 3731 Comm: kworker/4:2 Not tainted 5.12.0-rc6+ #54"
8: B1 Line exceeds max length (111>80): "[ 179.148432][ T3731] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014"
##############################
Test: BuildKernel - PASS - 599.16 seconds
Build Kernel with minimal configuration supports Bluetooth
##############################
Test: TestRunner: Setup - PASS - 400.87 seconds
Setup environment for running Test Runner
##############################
Test: TestRunner: l2cap-tester - PASS - 3.02 seconds
Run test-runner with l2cap-tester
Total: 40, Passed: 40 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner: bnep-tester - PASS - 2.10 seconds
Run test-runner with bnep-tester
Total: 1, Passed: 1 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner: mgmt-tester - PASS - 34.08 seconds
Run test-runner with mgmt-tester
Total: 452, Passed: 452 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner: rfcomm-tester - PASS - 2.32 seconds
Run test-runner with rfcomm-tester
Total: 9, Passed: 9 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner: sco-tester - PASS - 2.28 seconds
Run test-runner with sco-tester
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner: smp-tester - PASS - 2.36 seconds
Run test-runner with smp-tester
Total: 8, Passed: 8 (100.0%), Failed: 0, Not Run: 0
##############################
Test: TestRunner: userchan-tester - PASS - 2.10 seconds
Run test-runner with userchan-tester
Total: 3, Passed: 3 (100.0%), Failed: 0, Not Run: 0
---
Regards,
Linux Bluetooth
Hi Luiz,
use-after-free error in lock_sock_nested is reported:
[ 179.140137][ T3731] =====================================================
[ 179.142675][ T3731] BUG: KMSAN: use-after-free in lock_sock_nested+0x280/0x2c0
[ 179.145494][ T3731] CPU: 4 PID: 3731 Comm: kworker/4:2 Not tainted 5.12.0-rc6+ #54
[ 179.148432][ T3731] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 179.151806][ T3731] Workqueue: events l2cap_chan_timeout
[ 179.152730][ T3731] Call Trace:
[ 179.153301][ T3731] dump_stack+0x24c/0x2e0
[ 179.154063][ T3731] kmsan_report+0xfb/0x1e0
[ 179.154855][ T3731] __msan_warning+0x5c/0xa0
[ 179.155579][ T3731] lock_sock_nested+0x280/0x2c0
[ 179.156436][ T3731] ? kmsan_get_metadata+0x116/0x180
[ 179.157257][ T3731] l2cap_sock_teardown_cb+0xb8/0x890
[ 179.158154][ T3731] ? __msan_metadata_ptr_for_load_8+0x10/0x20
[ 179.159141][ T3731] ? kmsan_get_metadata+0x116/0x180
[ 179.159994][ T3731] ? kmsan_get_shadow_origin_ptr+0x84/0xb0
[ 179.160959][ T3731] ? l2cap_sock_recv_cb+0x420/0x420
[ 179.161834][ T3731] l2cap_chan_del+0x3e1/0x1d50
[ 179.162608][ T3731] ? kmsan_get_metadata+0x116/0x180
[ 179.163435][ T3731] ? kmsan_get_shadow_origin_ptr+0x84/0xb0
[ 179.164406][ T3731] l2cap_chan_close+0xeea/0x1050
[ 179.165189][ T3731] ? kmsan_internal_unpoison_shadow+0x42/0x70
[ 179.166180][ T3731] l2cap_chan_timeout+0x1da/0x590
[ 179.167066][ T3731] ? __msan_metadata_ptr_for_load_8+0x10/0x20
[ 179.168023][ T3731] ? l2cap_chan_create+0x560/0x560
[ 179.168818][ T3731] process_one_work+0x121d/0x1ff0
[ 179.169598][ T3731] worker_thread+0x121b/0x2370
[ 179.170346][ T3731] kthread+0x4ef/0x610
[ 179.171010][ T3731] ? process_one_work+0x1ff0/0x1ff0
[ 179.171828][ T3731] ? kthread_blkcg+0x110/0x110
[ 179.172587][ T3731] ret_from_fork+0x1f/0x30
[ 179.173348][ T3731]
[ 179.173752][ T3731] Uninit was created at:
[ 179.174409][ T3731] kmsan_internal_poison_shadow+0x5c/0xf0
[ 179.175373][ T3731] kmsan_slab_free+0x76/0xc0
[ 179.176060][ T3731] kfree+0x3a5/0x1180
[ 179.176664][ T3731] __sk_destruct+0x8af/0xb80
[ 179.177375][ T3731] __sk_free+0x812/0x8c0
[ 179.178032][ T3731] sk_free+0x97/0x130
[ 179.178686][ T3731] l2cap_sock_release+0x3d5/0x4d0
[ 179.179457][ T3731] sock_close+0x150/0x450
[ 179.180117][ T3731] __fput+0x6bd/0xf00
[ 179.180787][ T3731] ____fput+0x37/0x40
[ 179.181481][ T3731] task_work_run+0x140/0x280
[ 179.182219][ T3731] do_exit+0xe51/0x3e60
[ 179.182930][ T3731] do_group_exit+0x20e/0x450
[ 179.183656][ T3731] get_signal+0x2dfb/0x38f0
[ 179.184344][ T3731] arch_do_signal_or_restart+0xaa/0xe10
[ 179.185266][ T3731] exit_to_user_mode_prepare+0x2d2/0x560
[ 179.186136][ T3731] syscall_exit_to_user_mode+0x35/0x60
[ 179.186984][ T3731] do_syscall_64+0xc5/0x140
[ 179.187681][ T3731] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 179.188604][ T3731] =====================================================
In our case, there are two Thread A and B:
Context: Thread A: Context: Thread B:
l2cap_chan_timeout() __se_sys_shutdown()
l2cap_chan_close() l2cap_sock_shutdown()
l2cap_chan_del() l2cap_chan_close()
l2cap_sock_teardown_cb() l2cap_sock_teardown_cb()
Once l2cap_sock_teardown_cb() excuted, this sock will be marked as SOCK_ZAPPED,
and can be treated as killable in l2cap_sock_kill() if sock_orphan() has
excuted, at this time we close sock through sock_close() which end to call
l2cap_sock_kill() like Thread C:
Context: Thread C:
sock_close()
l2cap_sock_release()
sock_orphan()
l2cap_sock_kill() #free sock if refcnt is 1
If C completed, Once A or B reaches l2cap_sock_teardown_cb() again,
use-after-free happened.
We should set chan->data to NULL if sock is destructed, for telling teardown
operation is not allowed in l2cap_sock_teardown_cb(), and also we should
avoid killing an already killed socket in l2cap_sock_close_cb().
Signed-off-by: Wang ShaoBo <redacted>
Signed-off-by: Luiz Augusto von Dentz <redacted>
---
net/bluetooth/l2cap_sock.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
patch has been applied to bluetooth-next tree.
Regards
Marcel