diff options
| author | Takashi Iwai <tiwai@suse.de> | 2026-09-12 18:21:42 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2026-09-13 09:07:08 +0200 |
| commit | fd95e68df6fe66344161a1329cbe5e5805e7b704 (patch) | |
| tree | 195abb43428222c90401d3d348d9145609c62f59 /sound | |
| parent | 76a986c980bb502c7688d605ac7a67fd257a9a1b (diff) | |
| download | linux-next-fd95e68df6fe66344161a1329cbe5e5805e7b704.tar.gz linux-next-fd95e68df6fe66344161a1329cbe5e5805e7b704.zip | |
ALSA: core: Fix potential UAF after asynchronous card release
Usually a sound driver releases the resources assigned to the card via
snd_card_free(), and it synchronizes with the whole release procedure.
However, when the card is released asynchronously via
snd_card_free_when_closed() like USB-audio driver, the situation is
slightly different; although the snd_card_disconnect() call at the
disconnection guarantees that any newer accesses will be gated, the
in-flight tasks might be still accessing to the underlying card->dev
device even after the disconnection, which would cause a
use-after-free in the end, as reported by fuzzers.
For addressing the bug above, this patch takes the refcount of
card->dev at initialization of the card object, and releases at its
destructor. This assures the availability of the card->dev in its
whole lifecycle.
Reported-by: Farhad Alemi <farhad.alemi@berkeley.edu>
Closes: https://lore.kernel.org/CA+0ovChexj4TrZL_2iG_P0WBEbZc5+73GfB3DkciQi=R8pZOnA@mail.gmail.com
Closes: https://lore.kernel.org/CA+0ovCgQUQNN=Z1tJTouiCsDaXR5M-3-SQEGk-cpPXQkM5Xh+w@mail.gmail.com
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20260912162150.455144-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
| -rw-r--r-- | sound/core/init.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sound/core/init.c b/sound/core/init.c index 2f7f83a7611b..d05bea3c87f5 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -310,7 +310,7 @@ static int snd_card_init(struct snd_card *card, struct device *parent, kfree(card); /* manually free here, as no destructor called */ return err; } - card->dev = parent; + card->dev = get_device(parent); card->number = idx; WARN_ON(IS_MODULE(CONFIG_SND) && !module); card->module = module; @@ -603,6 +603,7 @@ static int snd_card_do_free(struct snd_card *card) dev_warn(card->dev, "unable to free card info\n"); /* Not fatal error */ } + put_device(card->dev); if (card->release_completion) complete(card->release_completion); if (!managed) |