* [alsa-devel] [PATCH] ALSA: usb-audio: Fix missing error check at mixer resolution test
@ 2019-11-09 18:16 Takashi Iwai
0 siblings, 0 replies; only message in thread
From: Takashi Iwai @ 2019-11-09 18:16 UTC (permalink / raw)
To: alsa-devel
A check of the return value from get_cur_mix_raw() is missing at the
resolution test code in get_min_max_with_quirks(), which may leave the
variable untouched, leading to a random uninitialized value, as
detected by syzkaller fuzzer.
Add the missing return error check for fixing that.
Reported-and-tested-by: syzbot+abe1ab7afc62c6bb6377@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/usb/mixer.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 3fd1d1749edf..45eee5cc312e 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1229,7 +1229,8 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
if (cval->min + cval->res < cval->max) {
int last_valid_res = cval->res;
int saved, test, check;
- get_cur_mix_raw(cval, minchn, &saved);
+ if (get_cur_mix_raw(cval, minchn, &saved) < 0)
+ goto no_res_check;
for (;;) {
test = saved;
if (test < cval->max)
@@ -1249,6 +1250,7 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
snd_usb_set_cur_mix_value(cval, minchn, 0, saved);
}
+no_res_check:
cval->initialized = 1;
}
--
2.16.4
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