diff options
author | Vladis Dronov <vdronov@redhat.com> | 2016-03-31 12:05:43 -0400 |
---|---|---|
committer | Sasha Levin <sasha.levin@oracle.com> | 2016-07-10 23:06:55 -0400 |
commit | 03e046efdbd3bccaac952553065adb70fb6976aa (patch) | |
tree | ef83c15bc17108e4b47d0d3d4608cffa0b7707d7 | |
parent | 00ef5df8687ff1a51660a5d27c202417a69b5018 (diff) |
ALSA: usb-audio: Fix double-free in error paths after snd_usb_add_audio_stream() call
[ Upstream commit 836b34a935abc91e13e63053d0a83b24dfb5ea78 ]
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>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r-- | sound/usb/quirks.c | 4 | ||||
-rw-r--r-- | sound/usb/stream.c | 6 |
2 files changed, 9 insertions, 1 deletions
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index dcd4b232544a..e27df0d3898b 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -147,6 +147,7 @@ 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; @@ -190,6 +191,7 @@ 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; @@ -465,6 +467,7 @@ 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: @@ -488,6 +491,7 @@ 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; } diff --git a/sound/usb/stream.c b/sound/usb/stream.c index 310a3822d2b7..25e8075f9ea3 100644 --- a/sound/usb/stream.c +++ b/sound/usb/stream.c @@ -315,7 +315,9 @@ static struct snd_pcm_chmap_elem *convert_chmap(int channels, unsigned int bits, /* * add this endpoint to the chip instance. * if a stream with the same endpoint already exists, append to it. - * if not, create a new pcm stream. + * if not, create a new pcm stream. note, fp is added to the substream + * fmt_list and will be freed on the chip instance release. do not free + * fp or do remove it from the substream fmt_list to avoid double-free. */ int snd_usb_add_audio_stream(struct snd_usb_audio *chip, int stream, @@ -668,6 +670,7 @@ int snd_usb_parse_audio_interface(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 */ @@ -716,6 +719,7 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no) dev_dbg(&dev->dev, "%u:%d: add audio endpoint %#x\n", iface_no, altno, fp->endpoint); err = snd_usb_add_audio_stream(chip, stream, fp); if (err < 0) { + list_del(&fp->list); /* unlink for avoiding double-free */ kfree(fp->rate_table); kfree(fp->chmap); kfree(fp); |