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Date: Sun, 11 Nov 2018 19:49:05 +0000
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org, "Bo Chen" <chenbo@....edu>,
"Takashi Iwai" <tiwai@...e.de>
Subject: [PATCH 3.16 104/366] ALSA: hda - Handle kzalloc() failure in
snd_hda_attach_pcm_stream()
3.16.61-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Bo Chen <chenbo@....edu>
commit a3aa60d511746bd6c0d0366d4eb90a7998bcde8b upstream.
When 'kzalloc()' fails in 'snd_hda_attach_pcm_stream()', a new pcm instance is
created without setting its operators via 'snd_pcm_set_ops()'. Following
operations on the new pcm instance can trigger kernel null pointer dereferences
and cause kernel oops.
This bug was found with my work on building a gray-box fault-injection tool for
linux-kernel-module binaries. A kernel null pointer dereference was confirmed
from line 'substream->ops->open()' in function 'snd_pcm_open_substream()' in
file 'sound/core/pcm_native.c'.
This patch fixes the bug by calling 'snd_device_free()' in the error handling
path of 'kzalloc()', which removes the new pcm instance from the snd card before
returns with an error code.
Signed-off-by: Bo Chen <chenbo@....edu>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
sound/pci/hda/hda_controller.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/sound/pci/hda/hda_controller.c
+++ b/sound/pci/hda/hda_controller.c
@@ -998,8 +998,10 @@ static int azx_attach_pcm_stream(struct
return err;
strlcpy(pcm->name, cpcm->name, sizeof(pcm->name));
apcm = kzalloc(sizeof(*apcm), GFP_KERNEL);
- if (apcm == NULL)
+ if (apcm == NULL) {
+ snd_device_free(chip->card, pcm);
return -ENOMEM;
+ }
apcm->chip = chip;
apcm->pcm = pcm;
apcm->codec = codec;
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