Re: [alsa-devel] [PATCH] sound/usb: Fix memory leak in media_snd_stream_delete() during unbind

On Thu, 17 Mar 2016 03:58:06 +0100, Shuah Khan wrote:

media_snd_stream_delete() fails to release resources during unbind. This leads to use-after-free in media_gobj_create() on a subsequent bind.

[ 1445.086410] BUG: KASAN: use-after-free in media_gobj_create+0x3a1/0x470 [media] at addr ffff8801ead49998

[ 1445.086771] Call Trace: [ 1445.086779] [<ffffffff81ade373>] dump_stack+0x67/0x94 [ 1445.086785] [<ffffffff81523c29>] print_trailer+0xf9/0x150 [ 1445.086790] [<ffffffff81529644>] object_err+0x34/0x40 [ 1445.086796] [<ffffffff8152b9e1>] kasan_report_error+0x221/0x530 [ 1445.086803] [<ffffffff8152bfb3>] __asan_report_store8_noabort+0x43/0x50 [ 1445.086813] [<ffffffffa0a79341>] ? media_gobj_create+0x3a1/0x470 [media] [ 1445.086822] [<ffffffffa0a79341>] media_gobj_create+0x3a1/0x470 [media] [ 1445.086831] [<ffffffffa0a705a9>] media_device_register_entity+0x259/0x6f0 [media] [ 1445.086841] [<ffffffffa0a70350>] ? media_device_unregister_entity_notify+0x100/0x100 [media] [ 1445.086846] [<ffffffff81526232>] ? ___slab_alloc+0x172/0x500 [ 1445.086854] [<ffffffff81203548>] ? mark_held_locks+0xc8/0x120 [ 1445.086859] [<ffffffff81526610>] ? __slab_alloc+0x50/0x70 [ 1445.086878] [<ffffffffa0fe711c>] ? media_snd_mixer_init+0x16c/0x500 [snd_usb_audio] [ 1445.086884] [<ffffffff8152b086>] ? kasan_unpoison_shadow+0x36/0x50 [ 1445.086890] [<ffffffff8152b086>] ? kasan_unpoison_shadow+0x36/0x50 [ 1445.086895] [<ffffffff8152b0fe>] ? kasan_kmalloc+0x5e/0x70

Signed-off-by: Shuah Khan shuahkh@osg.samsung.com

Mauro, please take it through your tree.

Acked-by: Takashi Iwai tiwai@suse.de

thanks,

Takashi

---

sound/usb/media.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/media.c b/sound/usb/media.c index 44a5de9..0d03773 100644 --- a/sound/usb/media.c +++ b/sound/usb/media.c @@ -135,7 +135,7 @@ void media_snd_stream_delete(struct snd_usb_substream *subs) if (mctl && mctl->media_dev) { struct media_device *mdev;

• mdev = subs->stream->chip->media_dev;
  

• mdev = mctl->media_dev;
  

  if (mdev && media_devnode_is_registered(&mdev->devnode)) { media_devnode_remove(mctl->intf_devnode); media_device_unregister_entity(&mctl->media_entity);

-- 2.5.0

---

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