[PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[Lee Jones]

This change prevents a use-after-free caused by one of the worker
threads starting up (see below) *after* the final channel reference
has been put() during sock_close() but *before* the references to the
channel have been destroyed.

  refcount_t: increment on 0; use-after-free.
  BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
  Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705

  CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W       4.14.234-00003-g1fb6d0bd49a4-dirty #28
  Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
  Workqueue: hci0 hci_rx_work
  Call trace:
   dump_backtrace+0x0/0x378
   show_stack+0x20/0x2c
   dump_stack+0x124/0x148
   print_address_description+0x80/0x2e8
   __kasan_report+0x168/0x188
   kasan_report+0x10/0x18
   __asan_load4+0x84/0x8c
   refcount_dec_and_test+0x20/0xd0
   l2cap_chan_put+0x48/0x12c
   l2cap_recv_frame+0x4770/0x6550
   l2cap_recv_acldata+0x44c/0x7a4
   hci_acldata_packet+0x100/0x188
   hci_rx_work+0x178/0x23c
   process_one_work+0x35c/0x95c
   worker_thread+0x4cc/0x960
   kthread+0x1a8/0x1c4
   ret_from_fork+0x10/0x18

Cc: stable@kernel.org
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-bluetooth@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 net/bluetooth/l2cap_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ae78490ecd3d4..82279c5919fd8 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -483,9 +483,7 @@ static void l2cap_chan_destroy(struct kref *kref)
 
 	BT_DBG("chan %p", chan);
 
-	write_lock(&chan_list_lock);
 	list_del(&chan->global_l);
-	write_unlock(&chan_list_lock);
 
 	kfree(chan);
 }
@@ -501,7 +499,9 @@ void l2cap_chan_put(struct l2cap_chan *c)
 {
 	BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
 
+	write_lock(&chan_list_lock);
 	kref_put(&c->kref, l2cap_chan_destroy);
+	write_unlock(&chan_list_lock);
 }
 EXPORT_SYMBOL_GPL(l2cap_chan_put);
 
-- 
2.36.1.255.ge46751e96f-goog

Re: [PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[Lee Jones]

On Tue, 07 Jun 2022, Lee Jones wrote:

> This change prevents a use-after-free caused by one of the worker
> threads starting up (see below) *after* the final channel reference
> has been put() during sock_close() but *before* the references to the
> channel have been destroyed.
> 
>   refcount_t: increment on 0; use-after-free.
>   BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
>   Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705
> 
>   CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W       4.14.234-00003-g1fb6d0bd49a4-dirty #28
>   Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
>   Workqueue: hci0 hci_rx_work
>   Call trace:
>    dump_backtrace+0x0/0x378
>    show_stack+0x20/0x2c
>    dump_stack+0x124/0x148
>    print_address_description+0x80/0x2e8
>    __kasan_report+0x168/0x188
>    kasan_report+0x10/0x18
>    __asan_load4+0x84/0x8c
>    refcount_dec_and_test+0x20/0xd0
>    l2cap_chan_put+0x48/0x12c
>    l2cap_recv_frame+0x4770/0x6550
>    l2cap_recv_acldata+0x44c/0x7a4
>    hci_acldata_packet+0x100/0x188
>    hci_rx_work+0x178/0x23c
>    process_one_work+0x35c/0x95c
>    worker_thread+0x4cc/0x960
>    kthread+0x1a8/0x1c4
>    ret_from_fork+0x10/0x18
> 
> Cc: stable@kernel.org
> Cc: Marcel Holtmann <marcel@holtmann.org>
> Cc: Johan Hedberg <johan.hedberg@gmail.com>
> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: linux-bluetooth@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Signed-off-by: Lee Jones <lee.jones@linaro.org>
> ---
>  net/bluetooth/l2cap_core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

No reply for 2 weeks.

Is this patch being considered at all?

Can I help in any way?

> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index ae78490ecd3d4..82279c5919fd8 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -483,9 +483,7 @@ static void l2cap_chan_destroy(struct kref *kref)
>  
>  	BT_DBG("chan %p", chan);
>  
> -	write_lock(&chan_list_lock);
>  	list_del(&chan->global_l);
> -	write_unlock(&chan_list_lock);
>  
>  	kfree(chan);
>  }
> @@ -501,7 +499,9 @@ void l2cap_chan_put(struct l2cap_chan *c)
>  {
>  	BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
>  
> +	write_lock(&chan_list_lock);
>  	kref_put(&c->kref, l2cap_chan_destroy);
> +	write_unlock(&chan_list_lock);
>  }
>  EXPORT_SYMBOL_GPL(l2cap_chan_put);
>  

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[Luiz Augusto von Dentz]

Hi Lee,

On Tue, Jun 21, 2022 at 7:38 AM Lee Jones <lee.jones@linaro.org> wrote:
>
> On Tue, 07 Jun 2022, Lee Jones wrote:
>
> > This change prevents a use-after-free caused by one of the worker
> > threads starting up (see below) *after* the final channel reference
> > has been put() during sock_close() but *before* the references to the
> > channel have been destroyed.
> >
> >   refcount_t: increment on 0; use-after-free.
> >   BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
> >   Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705
> >
> >   CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W       4.14.234-00003-g1fb6d0bd49a4-dirty #28
> >   Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
> >   Workqueue: hci0 hci_rx_work
> >   Call trace:
> >    dump_backtrace+0x0/0x378
> >    show_stack+0x20/0x2c
> >    dump_stack+0x124/0x148
> >    print_address_description+0x80/0x2e8
> >    __kasan_report+0x168/0x188
> >    kasan_report+0x10/0x18
> >    __asan_load4+0x84/0x8c
> >    refcount_dec_and_test+0x20/0xd0
> >    l2cap_chan_put+0x48/0x12c
> >    l2cap_recv_frame+0x4770/0x6550
> >    l2cap_recv_acldata+0x44c/0x7a4
> >    hci_acldata_packet+0x100/0x188
> >    hci_rx_work+0x178/0x23c
> >    process_one_work+0x35c/0x95c
> >    worker_thread+0x4cc/0x960
> >    kthread+0x1a8/0x1c4
> >    ret_from_fork+0x10/0x18
> >
> > Cc: stable@kernel.org
> > Cc: Marcel Holtmann <marcel@holtmann.org>
> > Cc: Johan Hedberg <johan.hedberg@gmail.com>
> > Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> > Cc: "David S. Miller" <davem@davemloft.net>
> > Cc: Eric Dumazet <edumazet@google.com>
> > Cc: Jakub Kicinski <kuba@kernel.org>
> > Cc: Paolo Abeni <pabeni@redhat.com>
> > Cc: linux-bluetooth@vger.kernel.org
> > Cc: netdev@vger.kernel.org
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> >  net/bluetooth/l2cap_core.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
>
> No reply for 2 weeks.
>
> Is this patch being considered at all?
>
> Can I help in any way?

Could you please resend to trigger CI, looks like CI missed this one
for some reason.

>
> > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> > index ae78490ecd3d4..82279c5919fd8 100644
> > --- a/net/bluetooth/l2cap_core.c
> > +++ b/net/bluetooth/l2cap_core.c
> > @@ -483,9 +483,7 @@ static void l2cap_chan_destroy(struct kref *kref)
> >
> >       BT_DBG("chan %p", chan);
> >
> > -     write_lock(&chan_list_lock);
> >       list_del(&chan->global_l);
> > -     write_unlock(&chan_list_lock);
> >
> >       kfree(chan);
> >  }
> > @@ -501,7 +499,9 @@ void l2cap_chan_put(struct l2cap_chan *c)
> >  {
> >       BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
> >
> > +     write_lock(&chan_list_lock);
> >       kref_put(&c->kref, l2cap_chan_destroy);
> > +     write_unlock(&chan_list_lock);
> >  }
> >  EXPORT_SYMBOL_GPL(l2cap_chan_put);
> >
>
> --
> Lee Jones [李琼斯]
> Principal Technical Lead - Developer Services
> Linaro.org │ Open source software for Arm SoCs
> Follow Linaro: Facebook | Twitter | Blog



-- 
Luiz Augusto von Dentz

Re: [PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[Luiz Augusto von Dentz]

Hi Lee,

On Tue, Jun 21, 2022 at 11:35 AM Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> Hi Lee,
>
> On Tue, Jun 21, 2022 at 7:38 AM Lee Jones <lee.jones@linaro.org> wrote:
> >
> > On Tue, 07 Jun 2022, Lee Jones wrote:
> >
> > > This change prevents a use-after-free caused by one of the worker
> > > threads starting up (see below) *after* the final channel reference
> > > has been put() during sock_close() but *before* the references to the
> > > channel have been destroyed.
> > >
> > >   refcount_t: increment on 0; use-after-free.
> > >   BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
> > >   Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705
> > >
> > >   CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W       4.14.234-00003-g1fb6d0bd49a4-dirty #28
> > >   Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
> > >   Workqueue: hci0 hci_rx_work
> > >   Call trace:
> > >    dump_backtrace+0x0/0x378
> > >    show_stack+0x20/0x2c
> > >    dump_stack+0x124/0x148
> > >    print_address_description+0x80/0x2e8
> > >    __kasan_report+0x168/0x188
> > >    kasan_report+0x10/0x18
> > >    __asan_load4+0x84/0x8c
> > >    refcount_dec_and_test+0x20/0xd0
> > >    l2cap_chan_put+0x48/0x12c
> > >    l2cap_recv_frame+0x4770/0x6550
> > >    l2cap_recv_acldata+0x44c/0x7a4
> > >    hci_acldata_packet+0x100/0x188
> > >    hci_rx_work+0x178/0x23c
> > >    process_one_work+0x35c/0x95c
> > >    worker_thread+0x4cc/0x960
> > >    kthread+0x1a8/0x1c4
> > >    ret_from_fork+0x10/0x18
> > >
> > > Cc: stable@kernel.org
> > > Cc: Marcel Holtmann <marcel@holtmann.org>
> > > Cc: Johan Hedberg <johan.hedberg@gmail.com>
> > > Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> > > Cc: "David S. Miller" <davem@davemloft.net>
> > > Cc: Eric Dumazet <edumazet@google.com>
> > > Cc: Jakub Kicinski <kuba@kernel.org>
> > > Cc: Paolo Abeni <pabeni@redhat.com>
> > > Cc: linux-bluetooth@vger.kernel.org
> > > Cc: netdev@vger.kernel.org
> > > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > > ---
> > >  net/bluetooth/l2cap_core.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > No reply for 2 weeks.
> >
> > Is this patch being considered at all?
> >
> > Can I help in any way?
>
> Could you please resend to trigger CI, looks like CI missed this one
> for some reason.

Btw, it would be great to have a test for this sort of fix so CI
reproduce and thus we avoid reintroducing it:

https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/tools/l2cap-tester.c

>
> >
> > > diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> > > index ae78490ecd3d4..82279c5919fd8 100644
> > > --- a/net/bluetooth/l2cap_core.c
> > > +++ b/net/bluetooth/l2cap_core.c
> > > @@ -483,9 +483,7 @@ static void l2cap_chan_destroy(struct kref *kref)
> > >
> > >       BT_DBG("chan %p", chan);
> > >
> > > -     write_lock(&chan_list_lock);
> > >       list_del(&chan->global_l);
> > > -     write_unlock(&chan_list_lock);
> > >
> > >       kfree(chan);
> > >  }
> > > @@ -501,7 +499,9 @@ void l2cap_chan_put(struct l2cap_chan *c)
> > >  {
> > >       BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
> > >
> > > +     write_lock(&chan_list_lock);
> > >       kref_put(&c->kref, l2cap_chan_destroy);
> > > +     write_unlock(&chan_list_lock);
> > >  }
> > >  EXPORT_SYMBOL_GPL(l2cap_chan_put);
> > >
> >
> > --
> > Lee Jones [李琼斯]
> > Principal Technical Lead - Developer Services
> > Linaro.org │ Open source software for Arm SoCs
> > Follow Linaro: Facebook | Twitter | Blog
>
>
>
> --
> Luiz Augusto von Dentz



-- 
Luiz Augusto von Dentz

Re: [PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[Lee Jones]

On Tue, 21 Jun 2022, Luiz Augusto von Dentz wrote:

> Hi Lee,
> 
> On Tue, Jun 21, 2022 at 7:38 AM Lee Jones <lee.jones@linaro.org> wrote:
> >
> > On Tue, 07 Jun 2022, Lee Jones wrote:
> >
> > > This change prevents a use-after-free caused by one of the worker
> > > threads starting up (see below) *after* the final channel reference
> > > has been put() during sock_close() but *before* the references to the
> > > channel have been destroyed.
> > >
> > >   refcount_t: increment on 0; use-after-free.
> > >   BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
> > >   Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705
> > >
> > >   CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W       4.14.234-00003-g1fb6d0bd49a4-dirty #28
> > >   Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
> > >   Workqueue: hci0 hci_rx_work
> > >   Call trace:
> > >    dump_backtrace+0x0/0x378
> > >    show_stack+0x20/0x2c
> > >    dump_stack+0x124/0x148
> > >    print_address_description+0x80/0x2e8
> > >    __kasan_report+0x168/0x188
> > >    kasan_report+0x10/0x18
> > >    __asan_load4+0x84/0x8c
> > >    refcount_dec_and_test+0x20/0xd0
> > >    l2cap_chan_put+0x48/0x12c
> > >    l2cap_recv_frame+0x4770/0x6550
> > >    l2cap_recv_acldata+0x44c/0x7a4
> > >    hci_acldata_packet+0x100/0x188
> > >    hci_rx_work+0x178/0x23c
> > >    process_one_work+0x35c/0x95c
> > >    worker_thread+0x4cc/0x960
> > >    kthread+0x1a8/0x1c4
> > >    ret_from_fork+0x10/0x18
> > >
> > > Cc: stable@kernel.org
> > > Cc: Marcel Holtmann <marcel@holtmann.org>
> > > Cc: Johan Hedberg <johan.hedberg@gmail.com>
> > > Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> > > Cc: "David S. Miller" <davem@davemloft.net>
> > > Cc: Eric Dumazet <edumazet@google.com>
> > > Cc: Jakub Kicinski <kuba@kernel.org>
> > > Cc: Paolo Abeni <pabeni@redhat.com>
> > > Cc: linux-bluetooth@vger.kernel.org
> > > Cc: netdev@vger.kernel.org
> > > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > > ---
> > >  net/bluetooth/l2cap_core.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > No reply for 2 weeks.
> >
> > Is this patch being considered at all?
> >
> > Can I help in any way?
> 
> Could you please resend to trigger CI, looks like CI missed this one
> for some reason.

Should I submit it as I did before?  Or did I miss a mailing address?

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation

[Luiz Augusto von Dentz]

Hi Lee,

On Tue, Jun 21, 2022 at 12:21 PM Lee Jones <lee.jones@linaro.org> wrote:
>
> On Tue, 21 Jun 2022, Luiz Augusto von Dentz wrote:
>
> > Hi Lee,
> >
> > On Tue, Jun 21, 2022 at 7:38 AM Lee Jones <lee.jones@linaro.org> wrote:
> > >
> > > On Tue, 07 Jun 2022, Lee Jones wrote:
> > >
> > > > This change prevents a use-after-free caused by one of the worker
> > > > threads starting up (see below) *after* the final channel reference
> > > > has been put() during sock_close() but *before* the references to the
> > > > channel have been destroyed.
> > > >
> > > >   refcount_t: increment on 0; use-after-free.
> > > >   BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
> > > >   Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705
> > > >
> > > >   CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S      W       4.14.234-00003-g1fb6d0bd49a4-dirty #28
> > > >   Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
> > > >   Workqueue: hci0 hci_rx_work
> > > >   Call trace:
> > > >    dump_backtrace+0x0/0x378
> > > >    show_stack+0x20/0x2c
> > > >    dump_stack+0x124/0x148
> > > >    print_address_description+0x80/0x2e8
> > > >    __kasan_report+0x168/0x188
> > > >    kasan_report+0x10/0x18
> > > >    __asan_load4+0x84/0x8c
> > > >    refcount_dec_and_test+0x20/0xd0
> > > >    l2cap_chan_put+0x48/0x12c
> > > >    l2cap_recv_frame+0x4770/0x6550
> > > >    l2cap_recv_acldata+0x44c/0x7a4
> > > >    hci_acldata_packet+0x100/0x188
> > > >    hci_rx_work+0x178/0x23c
> > > >    process_one_work+0x35c/0x95c
> > > >    worker_thread+0x4cc/0x960
> > > >    kthread+0x1a8/0x1c4
> > > >    ret_from_fork+0x10/0x18
> > > >
> > > > Cc: stable@kernel.org
> > > > Cc: Marcel Holtmann <marcel@holtmann.org>
> > > > Cc: Johan Hedberg <johan.hedberg@gmail.com>
> > > > Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> > > > Cc: "David S. Miller" <davem@davemloft.net>
> > > > Cc: Eric Dumazet <edumazet@google.com>
> > > > Cc: Jakub Kicinski <kuba@kernel.org>
> > > > Cc: Paolo Abeni <pabeni@redhat.com>
> > > > Cc: linux-bluetooth@vger.kernel.org
> > > > Cc: netdev@vger.kernel.org
> > > > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > > > ---
> > > >  net/bluetooth/l2cap_core.c | 4 ++--
> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > No reply for 2 weeks.
> > >
> > > Is this patch being considered at all?
> > >
> > > Can I help in any way?
> >
> > Could you please resend to trigger CI, looks like CI missed this one
> > for some reason.
>
> Should I submit it as I did before?  Or did I miss a mailing address?

Just resend, you can tag with RESEND, looks like the original one got
stuck in CI since only 1 test was run:

https://patchwork.kernel.org/project/bluetooth/patch/20220607134709.373344-1-lee.jones@linaro.org/

> --
> Lee Jones [李琼斯]
> Principal Technical Lead - Developer Services
> Linaro.org │ Open source software for Arm SoCs
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-- 
Luiz Augusto von Dentz