From 2f7a26abb8241a0208c68d22815aa247c5ddacab Mon Sep 17 00:00:00 2001
From: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Date: Sat, 9 Apr 2022 03:26:55 +0200
Subject: [PATCH] ALSA: pcm: Test for "silence" field in struct "pcm_format_data"
Git-commit: 2f7a26abb8241a0208c68d22815aa247c5ddacab
Patch-mainline: v5.18-rc3
References: git-fixes
Syzbot reports "KASAN: null-ptr-deref Write in
snd_pcm_format_set_silence".[1]
It is due to missing validation of the "silence" field of struct
"pcm_format_data" in "pcm_formats" array.
Add a test for valid "pat" and, if it is not so, return -EINVAL.
[1] https://lore.kernel.org/lkml/000000000000d188ef05dc2c7279@google.com/
Reported-and-tested-by: syzbot+205eb15961852c2c5974@syzkaller.appspotmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220409012655.9399-1-fmdefrancesco@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/core/pcm_misc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/core/pcm_misc.c b/sound/core/pcm_misc.c
index 4866aed97aac..5588b6a1ee8b 100644
--- a/sound/core/pcm_misc.c
+++ b/sound/core/pcm_misc.c
@@ -433,7 +433,7 @@ int snd_pcm_format_set_silence(snd_pcm_format_t format, void *data, unsigned int
return 0;
width = pcm_formats[(INT)format].phys; /* physical width */
pat = pcm_formats[(INT)format].silence;
- if (! width)
+ if (!width || !pat)
return -EINVAL;
/* signed or 1 byte data */
if (pcm_formats[(INT)format].signd == 1 || width <= 8) {
--
2.31.1