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authorVladis Dronov <vdronov@redhat.com>2016-03-31 12:05:43 -0400
committerSimon Shields <keepcalm444@gmail.com>2016-11-11 13:26:51 +1100
commit4c72b649cb557ff8b613b94bd68471ecfb42f0fb (patch)
treebe973a58f8ba162d20a0d9e6218a22ba799fd775
parent60117f1016086f658c7d765a7f928e217699dbc4 (diff)
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ALSA: usb-audio: Fix double-free in error paths after snd_usb_add_audio_stream() call
commit 836b34a935abc91e13e63053d0a83b24dfb5ea78 upstream. 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()')] Change-Id: Ia332409f06bbd20c0abf9cf915f4a041200e4736 Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1283358 Reported-by: Ralf Spenneberg <ralf@spenneberg.net> Signed-off-by: Vladis Dronov <vdronov@redhat.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--sound/usb/endpoint.c2
-rw-r--r--sound/usb/quirks.c4
2 files changed, 6 insertions, 0 deletions
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 05842c8b067..2d7b5e719bd 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -393,6 +393,7 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
* (fp->maxpacksize & 0x7ff);
fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
fp->clock = clock;
+ INIT_LIST_HEAD(&fp->list);
/* some quirks for attributes here */
@@ -434,6 +435,7 @@ int snd_usb_parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no)
snd_printdd(KERN_INFO "%d:%u:%d: add audio endpoint %#x\n", dev->devnum, iface_no, altno, fp->endpoint);
err = snd_usb_add_audio_endpoint(chip, stream, fp);
if (err < 0) {
+ list_del(&fp->list); /* unlink for avoiding double-free */
kfree(fp->rate_table);
kfree(fp);
return err;
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 39e5c776ac6..d7f182228aa 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -139,6 +139,7 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
kfree(fp);
return -EINVAL;
}
+ INIT_LIST_HEAD(&fp->list);
if (fp->nr_rates > 0) {
rate_table = kmalloc(sizeof(int) * fp->nr_rates, GFP_KERNEL);
if (!rate_table) {
@@ -173,6 +174,7 @@ 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;
@@ -243,6 +245,7 @@ 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:
@@ -266,6 +269,7 @@ static int create_uaxx_quirk(struct snd_usb_audio *chip,
? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
err = snd_usb_add_audio_endpoint(chip, stream, fp);
if (err < 0) {
+ list_del(&fp->list); /* unlink for avoiding double-free */
kfree(fp);
return err;
}