From 0e888a74e52db369e19aec908131cf171079b306 Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Fri, 19 Nov 2021 17:08:49 -0600
Subject: [PATCH] ALSA: pcm: unconditionally check if appl_ptr is in 0..boundary range
Git-commit: 0e888a74e52db369e19aec908131cf171079b306
Patch-mainline: v5.17-rc1
References: jsc#PED-850

In some cases, the appl_ptr passed by userspace is not checked before
being used. This patch adds an unconditional check and returns an
error code should the appl_ptr exceed the ALSA 'boundary'.

Suggested-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20211119230852.206310-2-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 sound/core/pcm_lib.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 4f4b4739f987..fdd992772b20 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -2133,6 +2133,9 @@ int pcm_lib_apply_appl_ptr(struct snd_pcm_substream *substream,
 	if (old_appl_ptr == appl_ptr)
 		return 0;
 
+	if (appl_ptr >= runtime->boundary)
+		return -EINVAL;
+
 	runtime->control->appl_ptr = appl_ptr;
 	if (substream->ops->ack) {
 		ret = substream->ops->ack(substream);
-- 
2.35.3