[PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Adrian Korwel]

Three bugs exist in this driver related to ALSA device file lifetime:

1. gaudio_open_snd_dev() opens the ALSA control file first, then the
   PCM playback file. If filp_open() for playback fails, the function
   returns without closing the already-opened control file handle.

2. playback_default_hw_params() return value was ignored. If it fails,
   both the control and playback file handles are leaked, causing
   gaudio_cleanup() to call filp_close() on already-freed file objects.

3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
   flag to prevent re-initialization, but the fail: error path
   unconditionally calls gaudio_cleanup(). On repeated bind attempts
   after failure, this closes file handles that were opened in a
   previous bind invocation and already freed by RCU, causing a
   use-after-free detected by KASAN:

   BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
   Read of size 8 at addr ffff88810d5523a8 by task bash/306
   ...
   gaudio_cleanup+0x59/0x100
   f_audio_bind+0x4b0/0x590

Fix all three issues:
- Close already-opened file handles on each error path in
  gaudio_open_snd_dev().
- Check and propagate the return value of playback_default_hw_params().
- Remove the 'bound' guard and call gaudio_setup() unconditionally in
  f_audio_bind(), making setup and cleanup a matched pair within each
  bind invocation. Remove the now-unused 'bound' field from the opts
  struct.

Additionally, f_audio_disable() was an empty stub. Add
cancel_work_sync() to ensure the playback work item is not in flight
when the function is unbound and the audio struct is freed.

Changes since v1:
- Added removal of the 'bound' guard in f_audio_bind() which was the
  root cause of the repeated-bind UAF
- Added cancel_work_sync() to f_audio_disable()
- Removed now-unused 'bound' field from struct f_uac1_legacy_opts

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1
implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 15 +++++++--------
 drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
 drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c
b/drivers/usb/gadget/function/f_uac1_legacy.c
index 5d201a2e30e7..798fbb8550bc 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -697,7 +697,9 @@ static int f_audio_get_alt(struct usb_function *f,
unsigned intf)

 static void f_audio_disable(struct usb_function *f)
 {
-       return;
+       struct f_audio *audio = func_to_audio(f);
+
+       cancel_work_sync(&audio->playback_work);
 }

 /*-------------------------------------------------------------------------*/
@@ -735,13 +737,10 @@ f_audio_bind(struct usb_configuration *c, struct
usb_function *f)

        audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
        audio->card.gadget = c->cdev->gadget;
-       /* set up ASLA audio devices */
-       if (!audio_opts->bound) {
-               status = gaudio_setup(&audio->card);
-               if (status < 0)
-                       return status;
-               audio_opts->bound = true;
-       }
+       /* set up ALSA audio devices */
+       status = gaudio_setup(&audio->card);
+       if (status < 0)
+               return status;
        us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
        if (IS_ERR(us))
                return PTR_ERR(us);
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.c
b/drivers/usb/gadget/function/u_uac1_legacy.c
index 01016102fa17..5bcd3afd6366 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.c
+++ b/drivers/usb/gadget/function/u_uac1_legacy.c
@@ -226,12 +226,20 @@ static int gaudio_open_snd_dev(struct gaudio *card)

                ERROR(card, "No such PCM playback device: %s\n", fn_play);
                snd->filp = NULL;
+               filp_close(card->control.filp, NULL);
+               card->control.filp = NULL;
                return ret;
        }
        pcm_file = snd->filp->private_data;
        snd->substream = pcm_file->substream;
        snd->card = card;
-       playback_default_hw_params(snd);
+       if (playback_default_hw_params(snd) < 0) {
+               filp_close(snd->filp, NULL);
+               snd->filp = NULL;
+               filp_close(card->control.filp, NULL);
+               card->control.filp = NULL;
+               return -EINVAL;
+       }

        /* Open PCM capture device and setup substream */
        snd = &card->capture;
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.h
b/drivers/usb/gadget/function/u_uac1_legacy.h
index b5df9bcbbeba..fd22fd37fe53 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.h
+++ b/drivers/usb/gadget/function/u_uac1_legacy.h
@@ -61,7 +61,6 @@ struct f_uac1_legacy_opts {
        char                            *fn_play;
        char                            *fn_cap;
        char                            *fn_cntl;
-       unsigned                        bound:1;
        unsigned                        fn_play_alloc:1;
        unsigned                        fn_cap_alloc:1;
        unsigned                        fn_cntl_alloc:1;
-- 
2.43.0

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Greg KH]

On Sun, May 24, 2026 at 11:33:21PM -0500, Adrian Korwel wrote:
> Three bugs exist in this driver related to ALSA device file lifetime:
> 
> 1. gaudio_open_snd_dev() opens the ALSA control file first, then the
>    PCM playback file. If filp_open() for playback fails, the function
>    returns without closing the already-opened control file handle.
> 
> 2. playback_default_hw_params() return value was ignored. If it fails,
>    both the control and playback file handles are leaked, causing
>    gaudio_cleanup() to call filp_close() on already-freed file objects.
> 
> 3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
>    flag to prevent re-initialization, but the fail: error path
>    unconditionally calls gaudio_cleanup(). On repeated bind attempts
>    after failure, this closes file handles that were opened in a
>    previous bind invocation and already freed by RCU, causing a
>    use-after-free detected by KASAN:
> 
>    BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
>    Read of size 8 at addr ffff88810d5523a8 by task bash/306
>    ...
>    gaudio_cleanup+0x59/0x100
>    f_audio_bind+0x4b0/0x590
> 
> Fix all three issues:
> - Close already-opened file handles on each error path in
>   gaudio_open_snd_dev().
> - Check and propagate the return value of playback_default_hw_params().
> - Remove the 'bound' guard and call gaudio_setup() unconditionally in
>   f_audio_bind(), making setup and cleanup a matched pair within each
>   bind invocation. Remove the now-unused 'bound' field from the opts
>   struct.

Why is this not broken up into smaller patches to corrispond with each
issue/fix?  Please do so.


> 
> Additionally, f_audio_disable() was an empty stub. Add
> cancel_work_sync() to ensure the playback work item is not in flight
> when the function is unbound and the audio struct is freed.
> 
> Changes since v1:
> - Added removal of the 'bound' guard in f_audio_bind() which was the
>   root cause of the repeated-bind UAF
> - Added cancel_work_sync() to f_audio_disable()
> - Removed now-unused 'bound' field from struct f_uac1_legacy_opts

The "changes" go below the --- line, right?

thanks,

greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Adrian Korwel]

On Mon, May 26, 2026 at 12:57AM, Greg KH wrote:
> Why is this not broken up into smaller patches...
> The "changes" go below the --- line, right?

Apologies for the formatting issues. Please find v3 below as a series
of 4 patches. Fixes split into separate patches and changelog moved
below the --- line.

Adrian Korwel (4):
  usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
  usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
  usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
  usb: typec: thunderbolt: cancel work before altmode is removed

 drivers/usb/gadget/function/f_uac1_legacy.c | 15 +++++++--------
 drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
 drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
 drivers/usb/typec/altmodes/thunderbolt.c    |  2 ++
 4 files changed, 18 insertions(+), 10 deletions(-)

On Mon, May 25, 2026 at 12:57 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Sun, May 24, 2026 at 11:33:21PM -0500, Adrian Korwel wrote:
> > Three bugs exist in this driver related to ALSA device file lifetime:
> >
> > 1. gaudio_open_snd_dev() opens the ALSA control file first, then the
> >    PCM playback file. If filp_open() for playback fails, the function
> >    returns without closing the already-opened control file handle.
> >
> > 2. playback_default_hw_params() return value was ignored. If it fails,
> >    both the control and playback file handles are leaked, causing
> >    gaudio_cleanup() to call filp_close() on already-freed file objects.
> >
> > 3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
> >    flag to prevent re-initialization, but the fail: error path
> >    unconditionally calls gaudio_cleanup(). On repeated bind attempts
> >    after failure, this closes file handles that were opened in a
> >    previous bind invocation and already freed by RCU, causing a
> >    use-after-free detected by KASAN:
> >
> >    BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
> >    Read of size 8 at addr ffff88810d5523a8 by task bash/306
> >    ...
> >    gaudio_cleanup+0x59/0x100
> >    f_audio_bind+0x4b0/0x590
> >
> > Fix all three issues:
> > - Close already-opened file handles on each error path in
> >   gaudio_open_snd_dev().
> > - Check and propagate the return value of playback_default_hw_params().
> > - Remove the 'bound' guard and call gaudio_setup() unconditionally in
> >   f_audio_bind(), making setup and cleanup a matched pair within each
> >   bind invocation. Remove the now-unused 'bound' field from the opts
> >   struct.
>
> Why is this not broken up into smaller patches to corrispond with each
> issue/fix?  Please do so.
>
>
> >
> > Additionally, f_audio_disable() was an empty stub. Add
> > cancel_work_sync() to ensure the playback work item is not in flight
> > when the function is unbound and the audio struct is freed.
> >
> > Changes since v1:
> > - Added removal of the 'bound' guard in f_audio_bind() which was the
> >   root cause of the repeated-bind UAF
> > - Added cancel_work_sync() to f_audio_disable()
> > - Removed now-unused 'bound' field from struct f_uac1_legacy_opts
>
> The "changes" go below the --- line, right?
>
> thanks,
>
> greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Adrian Korwel]

[PATCH v3 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in
gaudio_open_snd_dev()

gaudio_open_snd_dev() opens the ALSA control device file first, then
opens the PCM playback device. On two error paths the control file
handle is leaked:

When filp_open() for the playback device fails, the function returns
immediately without closing the already-opened control file handle.

When playback_default_hw_params() fails, its return value was ignored
and both the playback and control file handles were leaked.

Both leaks result in gaudio_cleanup() calling filp_close() on already
freed file objects, causing a use-after-free.

Fix by closing previously opened file handles before returning on
each error path, and by checking the return value of
playback_default_hw_params().

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1
implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/u_uac1_legacy.c
b/drivers/usb/gadget/function/u_uac1_legacy.c
index 01016102fa17..5bcd3afd6366 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.c
+++ b/drivers/usb/gadget/function/u_uac1_legacy.c
@@ -226,12 +226,20 @@ static int gaudio_open_snd_dev(struct gaudio *card)

                ERROR(card, "No such PCM playback device: %s\n", fn_play);
                snd->filp = NULL;
+               filp_close(card->control.filp, NULL);
+               card->control.filp = NULL;
                return ret;
        }
        pcm_file = snd->filp->private_data;
        snd->substream = pcm_file->substream;
        snd->card = card;
-       playback_default_hw_params(snd);
+       if (playback_default_hw_params(snd) < 0) {
+               filp_close(snd->filp, NULL);
+               snd->filp = NULL;
+               filp_close(card->control.filp, NULL);
+               card->control.filp = NULL;
+               return -EINVAL;
+       }

        /* Open PCM capture device and setup substream */
        snd = &card->capture;
-- 
2.43.0

On Mon, May 25, 2026 at 9:30 AM Adrian Korwel <adriank20047@gmail.com> wrote:
>
> On Mon, May 26, 2026 at 12:57AM, Greg KH wrote:
> > Why is this not broken up into smaller patches...
> > The "changes" go below the --- line, right?
>
> Apologies for the formatting issues. Please find v3 below as a series
> of 4 patches. Fixes split into separate patches and changelog moved
> below the --- line.
>
> Adrian Korwel (4):
>   usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
>   usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
>   usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
>   usb: typec: thunderbolt: cancel work before altmode is removed
>
>  drivers/usb/gadget/function/f_uac1_legacy.c | 15 +++++++--------
>  drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
>  drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
>  drivers/usb/typec/altmodes/thunderbolt.c    |  2 ++
>  4 files changed, 18 insertions(+), 10 deletions(-)
>
> On Mon, May 25, 2026 at 12:57 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, May 24, 2026 at 11:33:21PM -0500, Adrian Korwel wrote:
> > > Three bugs exist in this driver related to ALSA device file lifetime:
> > >
> > > 1. gaudio_open_snd_dev() opens the ALSA control file first, then the
> > >    PCM playback file. If filp_open() for playback fails, the function
> > >    returns without closing the already-opened control file handle.
> > >
> > > 2. playback_default_hw_params() return value was ignored. If it fails,
> > >    both the control and playback file handles are leaked, causing
> > >    gaudio_cleanup() to call filp_close() on already-freed file objects.
> > >
> > > 3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
> > >    flag to prevent re-initialization, but the fail: error path
> > >    unconditionally calls gaudio_cleanup(). On repeated bind attempts
> > >    after failure, this closes file handles that were opened in a
> > >    previous bind invocation and already freed by RCU, causing a
> > >    use-after-free detected by KASAN:
> > >
> > >    BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
> > >    Read of size 8 at addr ffff88810d5523a8 by task bash/306
> > >    ...
> > >    gaudio_cleanup+0x59/0x100
> > >    f_audio_bind+0x4b0/0x590
> > >
> > > Fix all three issues:
> > > - Close already-opened file handles on each error path in
> > >   gaudio_open_snd_dev().
> > > - Check and propagate the return value of playback_default_hw_params().
> > > - Remove the 'bound' guard and call gaudio_setup() unconditionally in
> > >   f_audio_bind(), making setup and cleanup a matched pair within each
> > >   bind invocation. Remove the now-unused 'bound' field from the opts
> > >   struct.
> >
> > Why is this not broken up into smaller patches to corrispond with each
> > issue/fix?  Please do so.
> >
> >
> > >
> > > Additionally, f_audio_disable() was an empty stub. Add
> > > cancel_work_sync() to ensure the playback work item is not in flight
> > > when the function is unbound and the audio struct is freed.
> > >
> > > Changes since v1:
> > > - Added removal of the 'bound' guard in f_audio_bind() which was the
> > >   root cause of the repeated-bind UAF
> > > - Added cancel_work_sync() to f_audio_disable()
> > > - Removed now-unused 'bound' field from struct f_uac1_legacy_opts
> >
> > The "changes" go below the --- line, right?
> >
> > thanks,
> >
> > greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Greg KH]

On Mon, May 25, 2026 at 09:33:12AM -0500, Adrian Korwel wrote:
> [PATCH v3 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in
> gaudio_open_snd_dev()

This should be in the subject line, not in the body of the emails.

Please resend a new version of all of these in the correct format.

thanks,

greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Adrian Korwel]

[PATCH v3 2/4] usb: gadget: f_uac1_legacy: fix use-after-free caused
by bound guard

f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound' flag
to prevent re-initialization on repeated bind attempts. However the
fail: error path unconditionally calls gaudio_cleanup(). On repeated
bind attempts after failure, this closes file handles that were opened
in a previous bind invocation and already freed by RCU, causing a
use-after-free detected by KASAN:

  BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
  Read of size 8 at addr ffff88810d5523a8 by task bash/306
  ...
  gaudio_cleanup+0x59/0x100
  f_audio_bind+0x4b0/0x590

Fix by removing the bound guard and calling gaudio_setup()
unconditionally in f_audio_bind(), making setup and cleanup a matched
pair within each bind invocation. Remove the now-unused 'bound' field
from struct f_uac1_legacy_opts.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1
implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 11 ++++-------
 drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c
b/drivers/usb/gadget/function/f_uac1_legacy.c
index 5d201a2e30e7..6ad4b16769b7 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -735,13 +735,10 @@ f_audio_bind(struct usb_configuration *c, struct
usb_function *f)

        audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
        audio->card.gadget = c->cdev->gadget;
-       /* set up ASLA audio devices */
-       if (!audio_opts->bound) {
-               status = gaudio_setup(&audio->card);
-               if (status < 0)
-                       return status;
-               audio_opts->bound = true;
-       }
+       /* set up ALSA audio devices */
+       status = gaudio_setup(&audio->card);
+       if (status < 0)
+               return status;
        us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
        if (IS_ERR(us))
                return PTR_ERR(us);
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.h
b/drivers/usb/gadget/function/u_uac1_legacy.h
index b5df9bcbbeba..fd22fd37fe53 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.h
+++ b/drivers/usb/gadget/function/u_uac1_legacy.h
@@ -61,7 +61,6 @@ struct f_uac1_legacy_opts {
        char                            *fn_play;
        char                            *fn_cap;
        char                            *fn_cntl;
-       unsigned                        bound:1;
        unsigned                        fn_play_alloc:1;
        unsigned                        fn_cap_alloc:1;
        unsigned                        fn_cntl_alloc:1;
-- 
2.43.0

On Mon, May 25, 2026 at 9:30 AM Adrian Korwel <adriank20047@gmail.com> wrote:
>
> On Mon, May 26, 2026 at 12:57AM, Greg KH wrote:
> > Why is this not broken up into smaller patches...
> > The "changes" go below the --- line, right?
>
> Apologies for the formatting issues. Please find v3 below as a series
> of 4 patches. Fixes split into separate patches and changelog moved
> below the --- line.
>
> Adrian Korwel (4):
>   usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
>   usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
>   usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
>   usb: typec: thunderbolt: cancel work before altmode is removed
>
>  drivers/usb/gadget/function/f_uac1_legacy.c | 15 +++++++--------
>  drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
>  drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
>  drivers/usb/typec/altmodes/thunderbolt.c    |  2 ++
>  4 files changed, 18 insertions(+), 10 deletions(-)
>
> On Mon, May 25, 2026 at 12:57 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, May 24, 2026 at 11:33:21PM -0500, Adrian Korwel wrote:
> > > Three bugs exist in this driver related to ALSA device file lifetime:
> > >
> > > 1. gaudio_open_snd_dev() opens the ALSA control file first, then the
> > >    PCM playback file. If filp_open() for playback fails, the function
> > >    returns without closing the already-opened control file handle.
> > >
> > > 2. playback_default_hw_params() return value was ignored. If it fails,
> > >    both the control and playback file handles are leaked, causing
> > >    gaudio_cleanup() to call filp_close() on already-freed file objects.
> > >
> > > 3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
> > >    flag to prevent re-initialization, but the fail: error path
> > >    unconditionally calls gaudio_cleanup(). On repeated bind attempts
> > >    after failure, this closes file handles that were opened in a
> > >    previous bind invocation and already freed by RCU, causing a
> > >    use-after-free detected by KASAN:
> > >
> > >    BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
> > >    Read of size 8 at addr ffff88810d5523a8 by task bash/306
> > >    ...
> > >    gaudio_cleanup+0x59/0x100
> > >    f_audio_bind+0x4b0/0x590
> > >
> > > Fix all three issues:
> > > - Close already-opened file handles on each error path in
> > >   gaudio_open_snd_dev().
> > > - Check and propagate the return value of playback_default_hw_params().
> > > - Remove the 'bound' guard and call gaudio_setup() unconditionally in
> > >   f_audio_bind(), making setup and cleanup a matched pair within each
> > >   bind invocation. Remove the now-unused 'bound' field from the opts
> > >   struct.
> >
> > Why is this not broken up into smaller patches to corrispond with each
> > issue/fix?  Please do so.
> >
> >
> > >
> > > Additionally, f_audio_disable() was an empty stub. Add
> > > cancel_work_sync() to ensure the playback work item is not in flight
> > > when the function is unbound and the audio struct is freed.
> > >
> > > Changes since v1:
> > > - Added removal of the 'bound' guard in f_audio_bind() which was the
> > >   root cause of the repeated-bind UAF
> > > - Added cancel_work_sync() to f_audio_disable()
> > > - Removed now-unused 'bound' field from struct f_uac1_legacy_opts
> >
> > The "changes" go below the --- line, right?
> >
> > thanks,
> >
> > greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Adrian Korwel]

[PATCH v3 3/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()

f_audio_disable() was an empty stub that simply returned without
cancelling the pending playback work item. The work function
f_audio_playback_work() accesses audio->lock, audio->play_queue and
audio->card which reside in the audio struct that is freed by
f_audio_free() after disable returns.

Fix by adding cancel_work_sync() to ensure the playback work item is
not in flight when the audio struct is freed.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1
implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c
b/drivers/usb/gadget/function/f_uac1_legacy.c
index 6ad4b16769b7..798fbb8550bc 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -697,7 +697,9 @@ static int f_audio_get_alt(struct usb_function *f,
unsigned intf)

 static void f_audio_disable(struct usb_function *f)
 {
-       return;
+       struct f_audio *audio = func_to_audio(f);
+
+       cancel_work_sync(&audio->playback_work);
 }

 /*-------------------------------------------------------------------------*/
-- 
2.43.0

On Mon, May 25, 2026 at 9:30 AM Adrian Korwel <adriank20047@gmail.com> wrote:
>
> On Mon, May 26, 2026 at 12:57AM, Greg KH wrote:
> > Why is this not broken up into smaller patches...
> > The "changes" go below the --- line, right?
>
> Apologies for the formatting issues. Please find v3 below as a series
> of 4 patches. Fixes split into separate patches and changelog moved
> below the --- line.
>
> Adrian Korwel (4):
>   usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
>   usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
>   usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
>   usb: typec: thunderbolt: cancel work before altmode is removed
>
>  drivers/usb/gadget/function/f_uac1_legacy.c | 15 +++++++--------
>  drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
>  drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
>  drivers/usb/typec/altmodes/thunderbolt.c    |  2 ++
>  4 files changed, 18 insertions(+), 10 deletions(-)
>
> On Mon, May 25, 2026 at 12:57 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, May 24, 2026 at 11:33:21PM -0500, Adrian Korwel wrote:
> > > Three bugs exist in this driver related to ALSA device file lifetime:
> > >
> > > 1. gaudio_open_snd_dev() opens the ALSA control file first, then the
> > >    PCM playback file. If filp_open() for playback fails, the function
> > >    returns without closing the already-opened control file handle.
> > >
> > > 2. playback_default_hw_params() return value was ignored. If it fails,
> > >    both the control and playback file handles are leaked, causing
> > >    gaudio_cleanup() to call filp_close() on already-freed file objects.
> > >
> > > 3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
> > >    flag to prevent re-initialization, but the fail: error path
> > >    unconditionally calls gaudio_cleanup(). On repeated bind attempts
> > >    after failure, this closes file handles that were opened in a
> > >    previous bind invocation and already freed by RCU, causing a
> > >    use-after-free detected by KASAN:
> > >
> > >    BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
> > >    Read of size 8 at addr ffff88810d5523a8 by task bash/306
> > >    ...
> > >    gaudio_cleanup+0x59/0x100
> > >    f_audio_bind+0x4b0/0x590
> > >
> > > Fix all three issues:
> > > - Close already-opened file handles on each error path in
> > >   gaudio_open_snd_dev().
> > > - Check and propagate the return value of playback_default_hw_params().
> > > - Remove the 'bound' guard and call gaudio_setup() unconditionally in
> > >   f_audio_bind(), making setup and cleanup a matched pair within each
> > >   bind invocation. Remove the now-unused 'bound' field from the opts
> > >   struct.
> >
> > Why is this not broken up into smaller patches to corrispond with each
> > issue/fix?  Please do so.
> >
> >
> > >
> > > Additionally, f_audio_disable() was an empty stub. Add
> > > cancel_work_sync() to ensure the playback work item is not in flight
> > > when the function is unbound and the audio struct is freed.
> > >
> > > Changes since v1:
> > > - Added removal of the 'bound' guard in f_audio_bind() which was the
> > >   root cause of the repeated-bind UAF
> > > - Added cancel_work_sync() to f_audio_disable()
> > > - Removed now-unused 'bound' field from struct f_uac1_legacy_opts
> >
> > The "changes" go below the --- line, right?
> >
> > thanks,
> >
> > greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Adrian Korwel]

[PATCH v3 4/4] usb: typec: thunderbolt: cancel work before altmode is removed

tbt_altmode_remove() frees resources associated with the Thunderbolt
altmode but does not cancel the pending work item before returning.
Since tbt is allocated with devm_kzalloc(), it is freed automatically
when the device is released after remove() returns.

The work item tbt_altmode_work() can be scheduled via schedule_work()
from tbt_altmode_vdm(), tbt_altmode_activate(), and the probe path,
and may still be pending or running when tbt_altmode_remove() returns.
The work function accesses tbt->lock, tbt->state, tbt->alt, and
tbt->plug[] — all of which reside in the freed struct, resulting in
a use-after-free.

Fix by calling cancel_work_sync() in tbt_altmode_remove() before
releasing any resources, ensuring no work item referencing tbt can
run after teardown begins.

Fixes: 100e25738659 ("usb: typec: Add driver for Thunderbolt 3 Alternate Mode")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/typec/altmodes/thunderbolt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/typec/altmodes/thunderbolt.c
b/drivers/usb/typec/altmodes/thunderbolt.c
index 32250b94262a..57c8dff0c51f 100644
--- a/drivers/usb/typec/altmodes/thunderbolt.c
+++ b/drivers/usb/typec/altmodes/thunderbolt.c
@@ -303,6 +303,8 @@ static void tbt_altmode_remove(struct typec_altmode *alt)
 {
        struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+       cancel_work_sync(&tbt->work);
+
        for (int i = TYPEC_PLUG_SOP_PP; i >= 0; --i) {
                if (tbt->plug[i])
                        typec_altmode_put_plug(tbt->plug[i]);
-- 
2.43.0

On Mon, May 25, 2026 at 9:30 AM Adrian Korwel <adriank20047@gmail.com> wrote:
>
> On Mon, May 26, 2026 at 12:57AM, Greg KH wrote:
> > Why is this not broken up into smaller patches...
> > The "changes" go below the --- line, right?
>
> Apologies for the formatting issues. Please find v3 below as a series
> of 4 patches. Fixes split into separate patches and changelog moved
> below the --- line.
>
> Adrian Korwel (4):
>   usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
>   usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
>   usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
>   usb: typec: thunderbolt: cancel work before altmode is removed
>
>  drivers/usb/gadget/function/f_uac1_legacy.c | 15 +++++++--------
>  drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
>  drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
>  drivers/usb/typec/altmodes/thunderbolt.c    |  2 ++
>  4 files changed, 18 insertions(+), 10 deletions(-)
>
> On Mon, May 25, 2026 at 12:57 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sun, May 24, 2026 at 11:33:21PM -0500, Adrian Korwel wrote:
> > > Three bugs exist in this driver related to ALSA device file lifetime:
> > >
> > > 1. gaudio_open_snd_dev() opens the ALSA control file first, then the
> > >    PCM playback file. If filp_open() for playback fails, the function
> > >    returns without closing the already-opened control file handle.
> > >
> > > 2. playback_default_hw_params() return value was ignored. If it fails,
> > >    both the control and playback file handles are leaked, causing
> > >    gaudio_cleanup() to call filp_close() on already-freed file objects.
> > >
> > > 3. f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound'
> > >    flag to prevent re-initialization, but the fail: error path
> > >    unconditionally calls gaudio_cleanup(). On repeated bind attempts
> > >    after failure, this closes file handles that were opened in a
> > >    previous bind invocation and already freed by RCU, causing a
> > >    use-after-free detected by KASAN:
> > >
> > >    BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
> > >    Read of size 8 at addr ffff88810d5523a8 by task bash/306
> > >    ...
> > >    gaudio_cleanup+0x59/0x100
> > >    f_audio_bind+0x4b0/0x590
> > >
> > > Fix all three issues:
> > > - Close already-opened file handles on each error path in
> > >   gaudio_open_snd_dev().
> > > - Check and propagate the return value of playback_default_hw_params().
> > > - Remove the 'bound' guard and call gaudio_setup() unconditionally in
> > >   f_audio_bind(), making setup and cleanup a matched pair within each
> > >   bind invocation. Remove the now-unused 'bound' field from the opts
> > >   struct.
> >
> > Why is this not broken up into smaller patches to corrispond with each
> > issue/fix?  Please do so.
> >
> >
> > >
> > > Additionally, f_audio_disable() was an empty stub. Add
> > > cancel_work_sync() to ensure the playback work item is not in flight
> > > when the function is unbound and the audio struct is freed.
> > >
> > > Changes since v1:
> > > - Added removal of the 'bound' guard in f_audio_bind() which was the
> > >   root cause of the repeated-bind UAF
> > > - Added cancel_work_sync() to f_audio_disable()
> > > - Removed now-unused 'bound' field from struct f_uac1_legacy_opts
> >
> > The "changes" go below the --- line, right?
> >
> > thanks,
> >
> > greg k-h

Re: [PATCH v2] usb: gadget: f_uac1_legacy: fix use-after-free in gaudio_open_snd_dev()

[Greg KH]

On Mon, May 25, 2026 at 09:37:52AM -0500, Adrian Korwel wrote:
> [PATCH v3 4/4] usb: typec: thunderbolt: cancel work before altmode is removed

Something went really wrong with this series, always use git send-email
or something else that can properly send patches :(

thanks,

greg k-h

[PATCH 1/4] USB: serial: io_ti: fix heap overflow in build_i2c_fw_hdr()

[Adrian Korwel]

build_i2c_fw_hdr() allocates a fixed-size buffer of
(16*1024 - 512) + sizeof(struct ti_i2c_firmware_rec) bytes, then
copies le16_to_cpu(img_header->Length) bytes into it without
validating that Length fits within the available space after the
firmware record header.

img_header->Length is a __le16 from the firmware file and can be
up to 65535. check_fw_sanity() validates the total firmware size
but not img_header->Length specifically.

Fix by rejecting images where img_header->Length exceeds the
available destination space.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/serial/io_ti.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index a35409bd766c..afe29fdf9536 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -844,6 +844,11 @@ static int build_i2c_fw_hdr(u8 *header, const struct firmware *fw)
 	/* Pointer to fw_down memory image */
 	img_header = (struct ti_i2c_image_header *)&fw->data[4];
 
+	if (le16_to_cpu(img_header->Length) >
+			buffer_size - sizeof(struct ti_i2c_firmware_rec)) {
+		kfree(buffer);
+		return -EINVAL;
+	}
 	memcpy(buffer + sizeof(struct ti_i2c_firmware_rec),
 		&fw->data[4 + sizeof(struct ti_i2c_image_header)],
 		le16_to_cpu(img_header->Length));
-- 
2.43.0

[PATCH 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()

[Adrian Korwel]

gaudio_open_snd_dev() opens the ALSA control device file first, then
opens the PCM playback device. On two error paths the control file
handle is leaked:

When filp_open() for the playback device fails, the function returns
immediately without closing the already-opened control file handle.

When playback_default_hw_params() fails, its return value was ignored
and both the playback and control file handles were leaked.

Both leaks result in gaudio_cleanup() calling filp_close() on already
freed file objects, causing a use-after-free.

Fix by closing previously opened file handles before returning on
each error path, and by checking the return value of
playback_default_hw_params().

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/u_uac1_legacy.c b/drivers/usb/gadget/function/u_uac1_legacy.c
index 01016102fa17..5bcd3afd6366 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.c
+++ b/drivers/usb/gadget/function/u_uac1_legacy.c
@@ -226,12 +226,20 @@ static int gaudio_open_snd_dev(struct gaudio *card)
 
 		ERROR(card, "No such PCM playback device: %s\n", fn_play);
 		snd->filp = NULL;
+		filp_close(card->control.filp, NULL);
+		card->control.filp = NULL;
 		return ret;
 	}
 	pcm_file = snd->filp->private_data;
 	snd->substream = pcm_file->substream;
 	snd->card = card;
-	playback_default_hw_params(snd);
+	if (playback_default_hw_params(snd) < 0) {
+		filp_close(snd->filp, NULL);
+		snd->filp = NULL;
+		filp_close(card->control.filp, NULL);
+		card->control.filp = NULL;
+		return -EINVAL;
+	}
 
 	/* Open PCM capture device and setup substream */
 	snd = &card->capture;
-- 
2.43.0

[PATCH 2/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()

[Adrian Korwel]

gaudio_open_snd_dev() opens the ALSA control device file first, then
opens the PCM playback device. On two error paths the control file
handle is leaked:

When filp_open() for the playback device fails, the function returns
immediately without closing the already-opened control file handle.

When playback_default_hw_params() fails, its return value was ignored
and both the playback and control file handles were leaked.

Both leaks result in gaudio_cleanup() calling filp_close() on already
freed file objects, causing a use-after-free.

Fix by closing previously opened file handles before returning on
each error path, and by checking the return value of
playback_default_hw_params().

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/u_uac1_legacy.c b/drivers/usb/gadget/function/u_uac1_legacy.c
index 01016102fa17..5bcd3afd6366 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.c
+++ b/drivers/usb/gadget/function/u_uac1_legacy.c
@@ -226,12 +226,20 @@ static int gaudio_open_snd_dev(struct gaudio *card)
 
 		ERROR(card, "No such PCM playback device: %s\n", fn_play);
 		snd->filp = NULL;
+		filp_close(card->control.filp, NULL);
+		card->control.filp = NULL;
 		return ret;
 	}
 	pcm_file = snd->filp->private_data;
 	snd->substream = pcm_file->substream;
 	snd->card = card;
-	playback_default_hw_params(snd);
+	if (playback_default_hw_params(snd) < 0) {
+		filp_close(snd->filp, NULL);
+		snd->filp = NULL;
+		filp_close(card->control.filp, NULL);
+		card->control.filp = NULL;
+		return -EINVAL;
+	}
 
 	/* Open PCM capture device and setup substream */
 	snd = &card->capture;
-- 
2.43.0

[PATCH 2/4] usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard

[Adrian Korwel]

f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound' flag
to prevent re-initialization on repeated bind attempts. However the
fail: error path unconditionally calls gaudio_cleanup(). On repeated
bind attempts after failure, this closes file handles that were opened
in a previous bind invocation and already freed by RCU, causing a
use-after-free detected by KASAN:

  BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
  Read of size 8 at addr ffff88810d5523a8 by task bash/306
  ...
  gaudio_cleanup+0x59/0x100
  f_audio_bind+0x4b0/0x590

Fix by removing the bound guard and calling gaudio_setup()
unconditionally in f_audio_bind(), making setup and cleanup a matched
pair within each bind invocation. Remove the now-unused 'bound' field
from struct f_uac1_legacy_opts.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 11 ++++-------
 drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 5d201a2e30e7..6ad4b16769b7 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -735,13 +735,10 @@ f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 
 	audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
 	audio->card.gadget = c->cdev->gadget;
-	/* set up ASLA audio devices */
-	if (!audio_opts->bound) {
-		status = gaudio_setup(&audio->card);
-		if (status < 0)
-			return status;
-		audio_opts->bound = true;
-	}
+	/* set up ALSA audio devices */
+	status = gaudio_setup(&audio->card);
+	if (status < 0)
+		return status;
 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
 	if (IS_ERR(us))
 		return PTR_ERR(us);
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.h b/drivers/usb/gadget/function/u_uac1_legacy.h
index b5df9bcbbeba..fd22fd37fe53 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.h
+++ b/drivers/usb/gadget/function/u_uac1_legacy.h
@@ -61,7 +61,6 @@ struct f_uac1_legacy_opts {
 	char				*fn_play;
 	char				*fn_cap;
 	char				*fn_cntl;
-	unsigned			bound:1;
 	unsigned			fn_play_alloc:1;
 	unsigned			fn_cap_alloc:1;
 	unsigned			fn_cntl_alloc:1;
-- 
2.43.0

[PATCH 3/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()

[Adrian Korwel]

f_audio_disable() was an empty stub that simply returned without
cancelling the pending playback work item. The work function
f_audio_playback_work() accesses audio->lock, audio->play_queue and
audio->card which reside in the audio struct that is freed by
f_audio_free() after disable returns.

Fix by adding cancel_work_sync() to ensure the playback work item is
not in flight when the audio struct is freed.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 6ad4b16769b7..798fbb8550bc 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -697,7 +697,9 @@ static int f_audio_get_alt(struct usb_function *f, unsigned intf)
 
 static void f_audio_disable(struct usb_function *f)
 {
-	return;
+	struct f_audio *audio = func_to_audio(f);
+
+	cancel_work_sync(&audio->playback_work);
 }
 
 /*-------------------------------------------------------------------------*/
-- 
2.43.0

[PATCH 3/4] usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard

[Adrian Korwel]

f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound' flag
to prevent re-initialization on repeated bind attempts. However the
fail: error path unconditionally calls gaudio_cleanup(). On repeated
bind attempts after failure, this closes file handles that were opened
in a previous bind invocation and already freed by RCU, causing a
use-after-free detected by KASAN:

  BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
  Read of size 8 at addr ffff88810d5523a8 by task bash/306
  ...
  gaudio_cleanup+0x59/0x100
  f_audio_bind+0x4b0/0x590

Fix by removing the bound guard and calling gaudio_setup()
unconditionally in f_audio_bind(), making setup and cleanup a matched
pair within each bind invocation. Remove the now-unused 'bound' field
from struct f_uac1_legacy_opts.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 11 ++++-------
 drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 5d201a2e30e7..6ad4b16769b7 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -735,13 +735,10 @@ f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 
 	audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
 	audio->card.gadget = c->cdev->gadget;
-	/* set up ASLA audio devices */
-	if (!audio_opts->bound) {
-		status = gaudio_setup(&audio->card);
-		if (status < 0)
-			return status;
-		audio_opts->bound = true;
-	}
+	/* set up ALSA audio devices */
+	status = gaudio_setup(&audio->card);
+	if (status < 0)
+		return status;
 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
 	if (IS_ERR(us))
 		return PTR_ERR(us);
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.h b/drivers/usb/gadget/function/u_uac1_legacy.h
index b5df9bcbbeba..fd22fd37fe53 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.h
+++ b/drivers/usb/gadget/function/u_uac1_legacy.h
@@ -61,7 +61,6 @@ struct f_uac1_legacy_opts {
 	char				*fn_play;
 	char				*fn_cap;
 	char				*fn_cntl;
-	unsigned			bound:1;
 	unsigned			fn_play_alloc:1;
 	unsigned			fn_cap_alloc:1;
 	unsigned			fn_cntl_alloc:1;
-- 
2.43.0

[PATCH 4/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()

[Adrian Korwel]

f_audio_disable() was an empty stub that simply returned without
cancelling the pending playback work item. The work function
f_audio_playback_work() accesses audio->lock, audio->play_queue and
audio->card which reside in the audio struct that is freed by
f_audio_free() after disable returns.

Fix by adding cancel_work_sync() to ensure the playback work item is
not in flight when the audio struct is freed.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 6ad4b16769b7..798fbb8550bc 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -697,7 +697,9 @@ static int f_audio_get_alt(struct usb_function *f, unsigned intf)
 
 static void f_audio_disable(struct usb_function *f)
 {
-	return;
+	struct f_audio *audio = func_to_audio(f);
+
+	cancel_work_sync(&audio->playback_work);
 }
 
 /*-------------------------------------------------------------------------*/
-- 
2.43.0

[PATCH 4/4] usb: typec: thunderbolt: cancel work before altmode is removed

[Adrian Korwel]

tbt_altmode_remove() frees resources associated with the Thunderbolt
altmode but does not cancel the pending work item before returning.
Since tbt is allocated with devm_kzalloc(), it is freed automatically
when the device is released after remove() returns.

The work item tbt_altmode_work() can be scheduled via schedule_work()
from tbt_altmode_vdm(), tbt_altmode_activate(), and the probe path,
and may still be pending or running when tbt_altmode_remove() returns.
The work function accesses tbt->lock, tbt->state, tbt->alt, and
tbt->plug[] — all of which reside in the freed struct, resulting in
a use-after-free.

Fix by calling cancel_work_sync() in tbt_altmode_remove() before
releasing any resources, ensuring no work item referencing tbt can
run after teardown begins.

Fixes: 100e25738659 ("usb: typec: Add driver for Thunderbolt 3 Alternate Mode")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/typec/altmodes/thunderbolt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/typec/altmodes/thunderbolt.c b/drivers/usb/typec/altmodes/thunderbolt.c
index 32250b94262a..57c8dff0c51f 100644
--- a/drivers/usb/typec/altmodes/thunderbolt.c
+++ b/drivers/usb/typec/altmodes/thunderbolt.c
@@ -303,6 +303,8 @@ static void tbt_altmode_remove(struct typec_altmode *alt)
 {
 	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
 
+	cancel_work_sync(&tbt->work);
+
 	for (int i = TYPEC_PLUG_SOP_PP; i >= 0; --i) {
 		if (tbt->plug[i])
 			typec_altmode_put_plug(tbt->plug[i]);
-- 
2.43.0

[PATCH 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()

[Adrian Korwel]

gaudio_open_snd_dev() opens the ALSA control device file first, then
opens the PCM playback device. On two error paths the control file
handle is leaked:

When filp_open() for the playback device fails, the function returns
immediately without closing the already-opened control file handle.

When playback_default_hw_params() fails, its return value was ignored
and both the playback and control file handles were leaked.

Both leaks result in gaudio_cleanup() calling filp_close() on already
freed file objects, causing a use-after-free.

Fix by closing previously opened file handles before returning on
each error path, and by checking the return value of
playback_default_hw_params().

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/u_uac1_legacy.c b/drivers/usb/gadget/function/u_uac1_legacy.c
index 01016102fa17..5bcd3afd6366 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.c
+++ b/drivers/usb/gadget/function/u_uac1_legacy.c
@@ -226,12 +226,20 @@ static int gaudio_open_snd_dev(struct gaudio *card)
 
 		ERROR(card, "No such PCM playback device: %s\n", fn_play);
 		snd->filp = NULL;
+		filp_close(card->control.filp, NULL);
+		card->control.filp = NULL;
 		return ret;
 	}
 	pcm_file = snd->filp->private_data;
 	snd->substream = pcm_file->substream;
 	snd->card = card;
-	playback_default_hw_params(snd);
+	if (playback_default_hw_params(snd) < 0) {
+		filp_close(snd->filp, NULL);
+		snd->filp = NULL;
+		filp_close(card->control.filp, NULL);
+		card->control.filp = NULL;
+		return -EINVAL;
+	}
 
 	/* Open PCM capture device and setup substream */
 	snd = &card->capture;
-- 
2.43.0

[PATCH 2/4] usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard

[Adrian Korwel]

f_audio_bind() guards gaudio_setup() with an 'audio_opts->bound' flag
to prevent re-initialization on repeated bind attempts. However the
fail: error path unconditionally calls gaudio_cleanup(). On repeated
bind attempts after failure, this closes file handles that were opened
in a previous bind invocation and already freed by RCU, causing a
use-after-free detected by KASAN:

  BUG: KASAN: slab-use-after-free in filp_flush+0x23/0x1b0
  Read of size 8 at addr ffff88810d5523a8 by task bash/306
  ...
  gaudio_cleanup+0x59/0x100
  f_audio_bind+0x4b0/0x590

Fix by removing the bound guard and calling gaudio_setup()
unconditionally in f_audio_bind(), making setup and cleanup a matched
pair within each bind invocation. Remove the now-unused 'bound' field
from struct f_uac1_legacy_opts.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 11 ++++-------
 drivers/usb/gadget/function/u_uac1_legacy.h |  1 -
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 5d201a2e30e7..6ad4b16769b7 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -735,13 +735,10 @@ f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 
 	audio_opts = container_of(f->fi, struct f_uac1_legacy_opts, func_inst);
 	audio->card.gadget = c->cdev->gadget;
-	/* set up ASLA audio devices */
-	if (!audio_opts->bound) {
-		status = gaudio_setup(&audio->card);
-		if (status < 0)
-			return status;
-		audio_opts->bound = true;
-	}
+	/* set up ALSA audio devices */
+	status = gaudio_setup(&audio->card);
+	if (status < 0)
+		return status;
 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
 	if (IS_ERR(us))
 		return PTR_ERR(us);
diff --git a/drivers/usb/gadget/function/u_uac1_legacy.h b/drivers/usb/gadget/function/u_uac1_legacy.h
index b5df9bcbbeba..fd22fd37fe53 100644
--- a/drivers/usb/gadget/function/u_uac1_legacy.h
+++ b/drivers/usb/gadget/function/u_uac1_legacy.h
@@ -61,7 +61,6 @@ struct f_uac1_legacy_opts {
 	char				*fn_play;
 	char				*fn_cap;
 	char				*fn_cntl;
-	unsigned			bound:1;
 	unsigned			fn_play_alloc:1;
 	unsigned			fn_cap_alloc:1;
 	unsigned			fn_cntl_alloc:1;
-- 
2.43.0

[PATCH 3/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()

[Adrian Korwel]

f_audio_disable() was an empty stub that simply returned without
cancelling the pending playback work item. The work function
f_audio_playback_work() accesses audio->lock, audio->play_queue and
audio->card which reside in the audio struct that is freed by
f_audio_free() after disable returns.

Fix by adding cancel_work_sync() to ensure the playback work item is
not in flight when the audio struct is freed.

Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/gadget/function/f_uac1_legacy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uac1_legacy.c b/drivers/usb/gadget/function/f_uac1_legacy.c
index 6ad4b16769b7..798fbb8550bc 100644
--- a/drivers/usb/gadget/function/f_uac1_legacy.c
+++ b/drivers/usb/gadget/function/f_uac1_legacy.c
@@ -697,7 +697,9 @@ static int f_audio_get_alt(struct usb_function *f, unsigned intf)
 
 static void f_audio_disable(struct usb_function *f)
 {
-	return;
+	struct f_audio *audio = func_to_audio(f);
+
+	cancel_work_sync(&audio->playback_work);
 }
 
 /*-------------------------------------------------------------------------*/
-- 
2.43.0

[PATCH 4/4] usb: typec: thunderbolt: cancel work before altmode is removed

[Adrian Korwel]

tbt_altmode_remove() frees resources associated with the Thunderbolt
altmode but does not cancel the pending work item before returning.
Since tbt is allocated with devm_kzalloc(), it is freed automatically
when the device is released after remove() returns.

The work item tbt_altmode_work() can be scheduled via schedule_work()
from tbt_altmode_vdm(), tbt_altmode_activate(), and the probe path,
and may still be pending or running when tbt_altmode_remove() returns.
The work function accesses tbt->lock, tbt->state, tbt->alt, and
tbt->plug[] — all of which reside in the freed struct, resulting in
a use-after-free.

Fix by calling cancel_work_sync() in tbt_altmode_remove() before
releasing any resources, ensuring no work item referencing tbt can
run after teardown begins.

Fixes: 100e25738659 ("usb: typec: Add driver for Thunderbolt 3 Alternate Mode")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
---
 drivers/usb/typec/altmodes/thunderbolt.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/typec/altmodes/thunderbolt.c b/drivers/usb/typec/altmodes/thunderbolt.c
index 32250b94262a..57c8dff0c51f 100644
--- a/drivers/usb/typec/altmodes/thunderbolt.c
+++ b/drivers/usb/typec/altmodes/thunderbolt.c
@@ -303,6 +303,8 @@ static void tbt_altmode_remove(struct typec_altmode *alt)
 {
 	struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
 
+	cancel_work_sync(&tbt->work);
+
 	for (int i = TYPEC_PLUG_SOP_PP; i >= 0; --i) {
 		if (tbt->plug[i])
 			typec_altmode_put_plug(tbt->plug[i]);
-- 
2.43.0

Re: [PATCH 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()

[Greg KH]

On Mon, May 25, 2026 at 03:26:09PM -0500, Adrian Korwel wrote:
> gaudio_open_snd_dev() opens the ALSA control device file first, then
> opens the PCM playback device. On two error paths the control file
> handle is leaked:
> 
> When filp_open() for the playback device fails, the function returns
> immediately without closing the already-opened control file handle.
> 
> When playback_default_hw_params() fails, its return value was ignored
> and both the playback and control file handles were leaked.
> 
> Both leaks result in gaudio_cleanup() calling filp_close() on already
> freed file objects, causing a use-after-free.
> 
> Fix by closing previously opened file handles before returning on
> each error path, and by checking the return value of
> playback_default_hw_params().
> 
> Fixes: d355339eecd9 ("usb: gadget: function: make current f_uac1 implementation legacy")
> Cc: stable@vger.kernel.org
> Signed-off-by: Adrian Korwel <adriank20047@gmail.com>
> ---
>  drivers/usb/gadget/function/u_uac1_legacy.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)

Something is really odd with your email system, look at what is on the
list from you for these patches.  It looks like:

 525   C May 25 Adrian Korwel   (  43) ┬─>[PATCH 1/2] USB: serial: io_ti: fix heap overflow in get_manuf_info()                                        
 527   C May 25 Adrian Korwel   (  40) │ └─>[PATCH 2/2] USB: serial: io_ti: fix heap overflow in build_i2c_fw_hdr()
 528   T May 25 Adrian Korwel   (  77) └─>Re: [PATCH] USB: serial: io_ti: fix heap overflows in get_manuf_info() and build_i2c_fw_hdr()
 623   C May 25 Adrian Korwel   (  54) ┬─>[PATCH 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
 624   C May 25 Adrian Korwel   (  64) │ ├─>[PATCH 2/4] usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
 625   C May 25 Adrian Korwel   (  40) │ ├─>[PATCH 4/4] usb: typec: thunderbolt: cancel work before altmode is removed
 626   C May 25 Adrian Korwel   (  35) │ └─>[PATCH 3/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
 627   C May 25 Adrian Korwel   (  40) └─>[PATCH 1/4] USB: serial: io_ti: fix heap overflow in build_i2c_fw_hdr()
 628   C May 25 Adrian Korwel   (  40)   ├─>[PATCH 4/4] usb: typec: thunderbolt: cancel work before altmode is removed
 629   C May 25 Adrian Korwel   (  35)   ├─>[PATCH 4/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
 630   C May 25 Adrian Korwel   (  54)   ├─>[PATCH 1/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
 631   C May 25 Adrian Korwel   (  64)   ├─>[PATCH 2/4] usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
 632   C May 25 Adrian Korwel   (  64)   ├─>[PATCH 3/4] usb: gadget: f_uac1_legacy: fix use-after-free caused by bound guard
 633   C May 25 Adrian Korwel   (  35)   ├─>[PATCH 3/4] usb: gadget: f_uac1_legacy: cancel work in f_audio_disable()
 634   C May 25 Adrian Korwel   (  54)   └─>[PATCH 2/4] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()
 636   C May 24 Adrian Korwel   (  41) [PATCH] usb: typec: thunderbolt: cancel work before altmode is removed  
 637   C May 24 Adrian Korwel   (  62) [PATCH] usb: gadget: f_uac1_legacy: fix file handle leaks in gaudio_open_snd_dev()


You have threading issues, patches in multiple places and resend, and all mixed
up.

Please resend everything that has not been accepted, as new versions, in the
correct way, and we will be glad to review them.

thanks,

greg k-h