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authorVladis Dronov <vdronov@redhat.com>2016-03-31 19:05:43 +0300
committerTakashi Iwai <tiwai@suse.de>2016-03-31 19:07:31 +0300
commit836b34a935abc91e13e63053d0a83b24dfb5ea78 (patch)
treeb2aaeb09188148c679f23eda13f7db4b933a65e9 /sound/usb/quirks.c
parent8eb22214b7cb0c0a28be6caf3b81201629d8ea7c (diff)
downloadlinux-836b34a935abc91e13e63053d0a83b24dfb5ea78.tar.xz
ALSA: usb-audio: Fix double-free in error paths after snd_usb_add_audio_stream() call
create_fixed_stream_quirk(), snd_usb_parse_audio_interface() and create_uaxx_quirk() functions allocate the audioformat object by themselves and free it upon error before returning. However, once the object is linked to a stream, it's freed again in snd_usb_audio_pcm_free(), thus it'll be double-freed, eventually resulting in a memory corruption. This patch fixes these failures in the error paths by unlinking the audioformat object before freeing it. Based on a patch by Takashi Iwai <tiwai@suse.de> [Note for stable backports: this patch requires the commit 902eb7fd1e4a ('ALSA: usb-audio: Minor code cleanup in create_fixed_stream_quirk()')] Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1283358 Reported-by: Ralf Spenneberg <ralf@spenneberg.net> Cc: <stable@vger.kernel.org> # see the note above Signed-off-by: Vladis Dronov <vdronov@redhat.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/quirks.c')
-rw-r--r--sound/usb/quirks.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index fb62bce2435c..6178bb5d0731 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -150,6 +150,7 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
usb_audio_err(chip, "cannot memdup\n");
return -ENOMEM;
}
+ INIT_LIST_HEAD(&fp->list);
if (fp->nr_rates > MAX_NR_RATES) {
kfree(fp);
return -EINVAL;
@@ -193,6 +194,7 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
return 0;
error:
+ list_del(&fp->list); /* unlink for avoiding double-free */
kfree(fp);
kfree(rate_table);
return err;
@@ -469,6 +471,7 @@ static int create_uaxx_quirk(struct snd_usb_audio *chip,
fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
fp->datainterval = 0;
fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
+ INIT_LIST_HEAD(&fp->list);
switch (fp->maxpacksize) {
case 0x120:
@@ -492,6 +495,7 @@ static int create_uaxx_quirk(struct snd_usb_audio *chip,
? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
err = snd_usb_add_audio_stream(chip, stream, fp);
if (err < 0) {
+ list_del(&fp->list); /* unlink for avoiding double-free */
kfree(fp);
return err;
}