Commit 167beb17 authored Nov 09, 2019 by Takashi Iwai

ALSA: usb-audio: Fix missing error check at mixer resolution test



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>
Link: https://lore.kernel.org/r/20191109181658.30368-1-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent df37d941

sound/usb/mixer.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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