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* [PATCH v2] Bluetooth: fix use-after-free error in lock_sock_nested()
@ 2021-07-19  2:49 Wang ShaoBo
       [not found] ` <20210719074829.2554-1-hdanton@sina.com>
  0 siblings, 1 reply; 4+ messages in thread
From: Wang ShaoBo @ 2021-07-19  2:49 UTC (permalink / raw)
  Cc: cj.chengjian, weiyongjun1, yuehaibing, huawei.libin, marcel,
	luiz.dentz, johan.hedberg, linux-bluetooth, netdev, linux-kernel

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 <bobo.shaobowang@huawei.com>
---
v2:
  put chan->data = NULL in l2cap_socl_destruct(), this refers to
  Luiz Augusto von Dentz <luiz.dentz@gmail.com>'s proposal.
---
 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);
-- 
2.27.0


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] Bluetooth: fix use-after-free error in lock_sock_nested()
       [not found] ` <20210719074829.2554-1-hdanton@sina.com>
@ 2021-07-19  9:03   ` Wangshaobo (bobo)
       [not found]     ` <20210720021619.621-1-hdanton@sina.com>
  0 siblings, 1 reply; 4+ messages in thread
From: Wangshaobo (bobo) @ 2021-07-19  9:03 UTC (permalink / raw)
  To: Hillf Danton
  Cc: cj.chengjian, weiyongjun1, yuehaibing, huawei.libin, marcel,
	luiz.dentz, johan.hedberg, linux-bluetooth, netdev, linux-kernel,
	syzbot, syzbot


在 2021/7/19 15:48, Hillf Danton 写道:
> On Mon, 19 Jul 2021 10:49:37 +0800 Wang ShaoBo wrote:
>> use-after-free error in lock_sock_nested is reported:
> There are similar reports from syzbot.
>
> [1] https://lore.kernel.org/netdev/000000000000f335f205b5649c70@google.com/
> [2] https://lore.kernel.org/netdev/000000000000c4fd0405b6cc8e53@google.com/
>
>> [  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
> Alternatively ensure it is safe to invoke the teardown cb by holding extra
> grab to sock, see diff below,
>
>> avoid killing an already killed socket in l2cap_sock_close_cb().
> with an eye on double kill.
>
>> Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
>> ---
>> v2:
>>   put chan->data = NULL in l2cap_socl_destruct(), this refers to
>>   Luiz Augusto von Dentz <luiz.dentz@gmail.com>'s proposal.
>> ---
>> 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);
>> -- 
>> 2.27.0
>
> Hold sock until it is killed to make l2cap callbacks safe.
> Now only for thoughts.
>
> +++ x/net/bluetooth/l2cap_sock.c
> @@ -1509,6 +1509,8 @@ static void l2cap_sock_close_cb(struct l
>   	struct sock *sk = chan->data;
>   
>   	l2cap_sock_kill(sk);
> +	/* put the extra hold in l2cap_sock_init() */
> +	sock_put(sk);
>   }
>   
>   static void l2cap_sock_teardown_cb(struct l2cap_chan *chan, int err)
> @@ -1794,6 +1796,8 @@ static void l2cap_sock_init(struct sock
>   	/* Default config options */
>   	chan->flush_to = L2CAP_DEFAULT_FLUSH_TO;
>   
> +	/* will be put in l2cap_sock_close_cb() */
> +	sock_hold(sk);
>   	chan->data = sk;
>   	chan->ops = &l2cap_chan_ops;
>   }
> .

Dear Danton,

I have tried this before, this will trigger error "underflow of refcount 
of chan" as following:

[  118.708179][ T3086] ------------[ cut here ]------------
[  118.710172][ T3086] refcount_t: underflow; use-after-free.
[  118.713391][ T3086] WARNING: CPU: 4 PID: 3086 at lib/refcount.c:28 
refcount_warn_saturate+0x30a/0x3c0
[  118.716774][ T3086] Modules linked in:
[  118.718279][ T3086] CPU: 4 PID: 3086 Comm: kworker/4:2 Not tainted 
5.12.0-rc6+ #84
[  118.721005][ T3086] Hardware name: QEMU Standard PC (i440FX + PIIX, 
1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[  118.722846][ T3086] Workqueue: events l2cap_chan_timeout
[  118.723786][ T3086] RIP: 0010:refcount_warn_saturate+0x30a/0x3c0
...
[  118.737912][ T3086] CR2: 0000000020000040 CR3: 0000000011029000 CR4: 
00000000000006e0
[  118.739187][ T3086] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
0000000000000000
[  118.740451][ T3086] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 
0000000000000400
[  118.741720][ T3086] Call Trace:
[  118.742262][ T3086]  l2cap_sock_close_cb+0x165/0x170
[  118.743124][ T3086]  ? l2cap_sock_teardown_cb+0x560/0x560

Actually, if adding sock_hold(sk) in l2cap_sock_init(), 
l2cap_sock_kill() will continue to excute untill it found

now chan's refcount is 0, this is because sock was not freed in last 
round execution of l2cap_sock_kill().


this method also makes l2cap_sock_init()'s logic more difficult to 
understand,   we have set refcount

of sock to 1 when allocating it, why do we need hold it again ?

-- Wang ShaoBo


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] Bluetooth: fix use-after-free error in lock_sock_nested()
       [not found]     ` <20210720021619.621-1-hdanton@sina.com>
@ 2021-07-20  4:24       ` Luiz Augusto von Dentz
       [not found]         ` <20210720062100.819-1-hdanton@sina.com>
  0 siblings, 1 reply; 4+ messages in thread
From: Luiz Augusto von Dentz @ 2021-07-20  4:24 UTC (permalink / raw)
  To: Hillf Danton
  Cc: Wangshaobo (bobo),
	cj.chengjian, Wei Yongjun, yuehaibing, huawei.libin,
	Marcel Holtmann, Johan Hedberg, linux-bluetooth,
	open list:NETWORKING [GENERAL],
	Linux Kernel Mailing List, syzbot, syzbot

Hi Hillf,

On Mon, Jul 19, 2021 at 7:16 PM Hillf Danton <hdanton@sina.com> wrote:
>
> On Mon, 19 Jul 2021 17:03:53 +0800 Wang ShaoBo wrote:
> >
> >I have tried this before, this will trigger error "underflow of refcount
> >of chan" as following:
> >
> >[  118.708179][ T3086] ------------[ cut here ]------------
> >[  118.710172][ T3086] refcount_t: underflow; use-after-free.
> >[  118.713391][ T3086] WARNING: CPU: 4 PID: 3086 at lib/refcount.c:28
> >refcount_warn_saturate+0x30a/0x3c0
> >[  118.716774][ T3086] Modules linked in:
> >[  118.718279][ T3086] CPU: 4 PID: 3086 Comm: kworker/4:2 Not tainted
> >5.12.0-rc6+ #84
> >[  118.721005][ T3086] Hardware name: QEMU Standard PC (i440FX + PIIX,
> >1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> >[  118.722846][ T3086] Workqueue: events l2cap_chan_timeout
> >[  118.723786][ T3086] RIP: 0010:refcount_warn_saturate+0x30a/0x3c0
> >...
> >[  118.737912][ T3086] CR2: 0000000020000040 CR3: 0000000011029000 CR4:
> >00000000000006e0
> >[  118.739187][ T3086] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> >0000000000000000
> >[  118.740451][ T3086] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> >0000000000000400
> >[  118.741720][ T3086] Call Trace:
> >[  118.742262][ T3086]  l2cap_sock_close_cb+0x165/0x170
> >[  118.743124][ T3086]  ? l2cap_sock_teardown_cb+0x560/0x560
> >
> >Actually, if adding sock_hold(sk) in l2cap_sock_init(),
> >l2cap_sock_kill() will continue to excute untill it found
> >
> >now chan's refcount is 0, this is because sock was not freed in last
> >round execution of l2cap_sock_kill().
>
> Well double kill cannot be walked around without adding more - add the
> destroy callback to make the chan->data recorded sock survive kill. It
> will be released when chan is destroyed to cut the race in reguards to
> accessing sock by making chan->data stable throughout chan's lifespan.
>
>
> +++ x/net/bluetooth/l2cap_core.c
> @@ -485,7 +485,10 @@ static void l2cap_chan_destroy(struct kr
>         list_del(&chan->global_l);
>         write_unlock(&chan_list_lock);
>
> -       kfree(chan);
> +       if (chan->ops && chan->ops->destroy)
> +               chan->ops->destroy(chan);
> +       else
> +               kfree(chan);

While Im fine adding a destroy callback the kfree shall be still in
l2cap_chan_destroy:

if (chan->ops && chan->ops->destroy)
  /* Destroy chan->data */
  chan->ops->destroy(chan->data);

kfree(chan);

>  }
>
>  void l2cap_chan_hold(struct l2cap_chan *c)
> +++ x/net/bluetooth/l2cap_sock.c
> @@ -1220,11 +1220,13 @@ static void l2cap_sock_kill(struct sock
>
>         BT_DBG("sk %p state %s", sk, state_to_string(sk->sk_state));
>
> +       /* double kill means noop */
> +       if (sock_flag(sk, SOCK_DEAD))
> +               return;
>         /* Kill poor orphan */
>
>         l2cap_chan_put(l2cap_pi(sk)->chan);
>         sock_set_flag(sk, SOCK_DEAD);
> -       sock_put(sk);
>  }
>
>  static int __l2cap_wait_ack(struct sock *sk, struct l2cap_chan *chan)
> @@ -1504,6 +1506,14 @@ done:
>         return err;
>  }
>
> +static void l2cap_sock_destroy_cb(struct l2cap_chan *chan)
> +{
> +       struct sock *sk = chan->data;
> +
> +       sock_put(sk);
> +       kfree(chan);
> +}
> +
>  static void l2cap_sock_close_cb(struct l2cap_chan *chan)
>  {
>         struct sock *sk = chan->data;
> @@ -1690,6 +1700,7 @@ static const struct l2cap_ops l2cap_chan
>         .new_connection         = l2cap_sock_new_connection_cb,
>         .recv                   = l2cap_sock_recv_cb,
>         .close                  = l2cap_sock_close_cb,
> +       .destroy                = l2cap_sock_destroy_cb,

If you do the changes above you can probably have sock_put directly
set as .destroy.

>         .teardown               = l2cap_sock_teardown_cb,
>         .state_change           = l2cap_sock_state_change_cb,
>         .ready                  = l2cap_sock_ready_cb,



-- 
Luiz Augusto von Dentz

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2] Bluetooth: fix use-after-free error in lock_sock_nested()
       [not found]         ` <20210720062100.819-1-hdanton@sina.com>
@ 2021-07-20 15:46           ` Luiz Augusto von Dentz
  0 siblings, 0 replies; 4+ messages in thread
From: Luiz Augusto von Dentz @ 2021-07-20 15:46 UTC (permalink / raw)
  To: Hillf Danton
  Cc: Wangshaobo (bobo),
	cj.chengjian, Wei Yongjun, yuehaibing, huawei.libin,
	Marcel Holtmann, Johan Hedberg, linux-bluetooth,
	open list:NETWORKING [GENERAL],
	Linux Kernel Mailing List, syzbot, syzbot

Hi Hillf,

On Mon, Jul 19, 2021 at 11:21 PM Hillf Danton <hdanton@sina.com> wrote:
>
> On Mon, 19 Jul 2021 21:24:30 -0700 Luiz Augusto von Dentz wrote:
> >
> >While Im fine adding a destroy callback the kfree shall be still in
> >l2cap_chan_destroy:
>
> Then feel free to send a tiny patchset to linux-bluetooth@vger.

What do you mean, we haven't applied your changes yet.


-- 
Luiz Augusto von Dentz

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-07-20 16:02 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-19  2:49 [PATCH v2] Bluetooth: fix use-after-free error in lock_sock_nested() Wang ShaoBo
     [not found] ` <20210719074829.2554-1-hdanton@sina.com>
2021-07-19  9:03   ` Wangshaobo (bobo)
     [not found]     ` <20210720021619.621-1-hdanton@sina.com>
2021-07-20  4:24       ` Luiz Augusto von Dentz
     [not found]         ` <20210720062100.819-1-hdanton@sina.com>
2021-07-20 15:46           ` Luiz Augusto von Dentz

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