APPLIED (hirsute/5.11): [PATCH 2/2] ALSA: usb-audio: fix use after free in usb_audio_disconnect

[Andrea Righi]

Applied to hirsute/5.11.

Thanks,
-Andrea

On Fri, Mar 12, 2021 at 02:56:05PM +0800, Kai-Heng Feng wrote:
> From: Pavel Skripkin <paskripkin at gmail.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1918670
> 
> The problem was in wrong "if" placement. chip->quirk_type is freed
> in snd_card_free_when_closed(), but inside if statement it's accesed.
> 
> Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
> Signed-off-by: Pavel Skripkin <paskripkin at gmail.com>
> Cc: <stable at vger.kernel.org>
> Link: https://lore.kernel.org/r/16da19126ff461e5e64a9aec648cce28fb8ed73e.1615242183.git.paskripkin@gmail.com
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> (cherry picked from commit c5aa956eaeb05fe87e33433d7fd9f5e4d23c7416 linux-next)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> ---
>  sound/usb/card.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 3fd1743513b5..b6f4c0848e66 100644
> --- a/sound/usb/card.c
> +++ b/sound/usb/card.c
> @@ -907,6 +907,9 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>  		}
>  	}
>  
> +	if (chip->quirk_type & QUIRK_SETUP_DISABLE_AUTOSUSPEND)
> +		usb_enable_autosuspend(interface_to_usbdev(intf));
> +
>  	chip->num_interfaces--;
>  	if (chip->num_interfaces <= 0) {
>  		usb_chip[chip->index] = NULL;
> @@ -915,9 +918,6 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>  	} else {
>  		mutex_unlock(&register_mutex);
>  	}
> -
> -	if (chip->quirk_type & QUIRK_SETUP_DISABLE_AUTOSUSPEND)
> -		usb_enable_autosuspend(interface_to_usbdev(intf));
>  }
>  
>  /* lock the shutdown (disconnect) task and autoresume */
> -- 
> 2.30.2
> 
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team

On Fri, Mar 12, 2021 at 02:56:04PM +0800, Kai-Heng Feng wrote:
> From: Pavel Skripkin <paskripkin at gmail.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1918670
> 
> syzbot reported null pointer dereference in usb_audio_probe.
> The problem was in case, when quirk == NULL. It's not an
> error condition, so quirk must be checked before dereferencing.
> 
> Call Trace:
>  usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396
>  really_probe+0x291/0xe60 drivers/base/dd.c:554
>  driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740
>  __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846
>  bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
>  __device_attach+0x228/0x4a0 drivers/base/dd.c:914
>  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
>  device_add+0xbdb/0x1db0 drivers/base/core.c:3242
>  usb_set_configuration+0x113f/0x1910 drivers/usb/core/message.c:2164
>  usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238
>  usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293
>  really_probe+0x291/0xe60 drivers/base/dd.c:554
>  driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740
>  __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846
>  bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431
>  __device_attach+0x228/0x4a0 drivers/base/dd.c:914
>  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
>  device_add+0xbdb/0x1db0 drivers/base/core.c:3242
>  usb_new_device.cold+0x721/0x1058 drivers/usb/core/hub.c:2555
>  hub_port_connect drivers/usb/core/hub.c:5223 [inline]
>  hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
>  port_event drivers/usb/core/hub.c:5509 [inline]
>  hub_event+0x2357/0x4320 drivers/usb/core/hub.c:5591
>  process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
>  worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
>  kthread+0x3b1/0x4a0 kernel/kthread.c:292
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
> 
> Reported-by: syzbot+719da9b149a931f5143f at syzkaller.appspotmail.com
> Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")
> Signed-off-by: Pavel Skripkin <paskripkin at gmail.com>
> Cc: <stable at vger.kernel.org>
> Link: https://lore.kernel.org/r/f1ebad6e721412843bd1b12584444c0a63c6b2fb.1615242183.git.paskripkin@gmail.com
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> (cherry picked from commit 30dea07180de3aa0ad613af88431ef4e34b5ef68 linux-next)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> ---
>  sound/usb/card.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 08c794883299..3fd1743513b5 100644
> --- a/sound/usb/card.c
> +++ b/sound/usb/card.c
> @@ -830,7 +830,8 @@ static int usb_audio_probe(struct usb_interface *intf,
>  		snd_media_device_create(chip, intf);
>  	}
>  
> -	chip->quirk_type = quirk->type;
> +	if (quirk)
> +		chip->quirk_type = quirk->type;
>  
>  	usb_chip[chip->index] = chip;
>  	chip->intf[chip->num_interfaces] = intf;
> -- 
> 2.30.2
> 
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team