From 0ad3f0b384d58f3bd1f4fb87d0af5b8f6866f41a Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 7 Apr 2020 10:44:01 +0200
Subject: [PATCH] ALSA: hda: Fix potential access overflow in beep helper
Git-commit: 0ad3f0b384d58f3bd1f4fb87d0af5b8f6866f41a
Patch-mainline: v5.7-rc1
References: bsc#1051510

The beep control helper function blindly stores the values in two
stereo channels no matter whether the actual control is mono or
stereo.  This is practically harmless, but it annoys the recently
introduced sanity check, resulting in an error when the checker is
enabled.

This patch corrects the behavior to store only on the defined array
member.

Fixes: 0401e8548eac ("ALSA: hda - Move beep helper functions to hda_beep.c")
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=207139
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200407084402.25589-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/pci/hda/hda_beep.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_beep.c b/sound/pci/hda/hda_beep.c
index f5fd62ed4df5..841523f6b88d 100644
--- a/sound/pci/hda/hda_beep.c
+++ b/sound/pci/hda/hda_beep.c
@@ -290,8 +290,12 @@ int snd_hda_mixer_amp_switch_get_beep(struct snd_kcontrol *kcontrol,
 {
 	struct hda_codec *codec = snd_kcontrol_chip(kcontrol);
 	struct hda_beep *beep = codec->beep;
+	int chs = get_amp_channels(kcontrol);
+
 	if (beep && (!beep->enabled || !ctl_has_mute(kcontrol))) {
-		ucontrol->value.integer.value[0] =
+		if (chs & 1)
+			ucontrol->value.integer.value[0] = beep->enabled;
+		if (chs & 2)
 			ucontrol->value.integer.value[1] = beep->enabled;
 		return 0;
 	}
-- 
2.16.4