From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 3 Nov 2020 10:18:07 +0000 (+0300)
Subject: ALSA: hda: prevent undefined shift in snd_hdac_ext_bus_get_link()
X-Git-Tag: v4.4.244~56
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f1a6e0d012c9b1ab7a23a9baef4628d7670a0562;p=thirdparty%2Fkernel%2Fstable.git

ALSA: hda: prevent undefined shift in snd_hdac_ext_bus_get_link()

[ Upstream commit 158e1886b6262c1d1c96a18c85fac5219b8bf804 ]

This is harmless, but the "addr" comes from the user and it could lead
to a negative shift or to shift wrapping if it's too high.

Fixes: 0b00a5615dc4 ("ALSA: hdac_ext: add hdac extended controller")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201103101807.GC1127762@mwanda
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/sound/hda/ext/hdac_ext_controller.c b/sound/hda/ext/hdac_ext_controller.c
index 63215b17247c8..379250dd0668e 100644
--- a/sound/hda/ext/hdac_ext_controller.c
+++ b/sound/hda/ext/hdac_ext_controller.c
@@ -221,6 +221,8 @@ struct hdac_ext_link *snd_hdac_ext_bus_get_link(struct hdac_ext_bus *ebus,
 		return NULL;
 	if (ebus->idx != bus_idx)
 		return NULL;
+	if (addr < 0 || addr > 31)
+		return NULL;
 
 	list_for_each_entry(hlink, &ebus->hlink_list, list) {
 		for (i = 0; i < HDA_MAX_CODECS; i++) {