From f93dc90c2e8ed664985e366aa6459ac83cdab236 Mon Sep 17 00:00:00 2001
From: Cezary Rojewski <cezary.rojewski@intel.com>
Date: Fri, 6 Oct 2023 12:28:55 +0200
Subject: [PATCH] ALSA: hda: Fix possible null-ptr-deref when assigning a stream
Git-commit: f93dc90c2e8ed664985e366aa6459ac83cdab236
Patch-mainline: v6.7-rc1
References: git-fixes
While AudioDSP drivers assign streams exclusively of HOST or LINK type,
nothing blocks a user to attempt to assign a COUPLED stream. As
supplied substream instance may be a stub, what is the case when
code-loading, such scenario ends with null-ptr-deref.
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20231006102857.749143-2-cezary.rojewski@intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/hda/hdac_stream.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c
index 5382894bebab..a132108fba40 100644
--- a/sound/hda/hdac_stream.c
+++ b/sound/hda/hdac_stream.c
@@ -362,8 +362,10 @@ struct hdac_stream *snd_hdac_stream_assign(struct hdac_bus *bus,
struct hdac_stream *res = NULL;
/* make a non-zero unique key for the substream */
- int key = (substream->pcm->device << 16) | (substream->number << 2) |
- (substream->stream + 1);
+ int key = (substream->number << 2) | (substream->stream + 1);
+
+ if (substream->pcm)
+ key |= (substream->pcm->device << 16);
spin_lock_irq(&bus->reg_lock);
list_for_each_entry(azx_dev, &bus->stream_list, list) {
--
2.35.3