diff options
| author | Lv Yunlong <lyl2019@mail.ustc.edu.cn> | 2021-04-26 06:11:29 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-22 10:38:19 +0200 |
| commit | adcdc6e36fd07a27e6e4288b3881c70d900b0e46 (patch) | |
| tree | 26cd043b2e2f4a7e394a51785225ee1d328a8139 | |
| parent | d27ab1d6b07225bcbfa7d853e226d9ad7b7f42e0 (diff) | |
ALSA: emu8000: Fix a use after free in snd_emu8000_create_mixer
commit 1c98f574403dbcf2eb832d5535a10d967333ef2d upstream.
Our code analyzer reported a uaf.
In snd_emu8000_create_mixer, the callee snd_ctl_add(..,emu->controls[i])
calls snd_ctl_add_replace(.., kcontrol,..). Inside snd_ctl_add_replace(),
if error happens, kcontrol will be freed by snd_ctl_free_one(kcontrol).
Then emu->controls[i] points to a freed memory, and the execution comes
to __error branch of snd_emu8000_create_mixer. The freed emu->controls[i]
is used in snd_ctl_remove(card, emu->controls[i]).
My patch set emu->controls[i] to NULL if snd_ctl_add() failed to avoid
the uaf.
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210426131129.4796-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | sound/isa/sb/emu8000.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/sound/isa/sb/emu8000.c b/sound/isa/sb/emu8000.c index 94c411299e5a..470058e89fef 100644 --- a/sound/isa/sb/emu8000.c +++ b/sound/isa/sb/emu8000.c @@ -1042,8 +1042,10 @@ snd_emu8000_create_mixer(struct snd_card *card, struct snd_emu8000 *emu) memset(emu->controls, 0, sizeof(emu->controls)); for (i = 0; i < EMU8000_NUM_CONTROLS; i++) { - if ((err = snd_ctl_add(card, emu->controls[i] = snd_ctl_new1(mixer_defs[i], emu))) < 0) + if ((err = snd_ctl_add(card, emu->controls[i] = snd_ctl_new1(mixer_defs[i], emu))) < 0) { + emu->controls[i] = NULL; goto __error; + } } return 0; |