ALSA: firewire: fix NULL pointer dereference when releasing uninitialized data of iso-resource

When calling 'iso_resource_free()' for uninitialized data, this function
causes NULL pointer dereference due to its 'unit' member. This occurs when
unplugging audio and music units on IEEE 1394 bus at failure of card
registration.

This commit fixes the bug. The bug exists since kernel v4.5.

Fixes: 324540c4e0 ('ALSA: fireface: postpone sound card registration') at v4.12
Fixes: 8865a31e0f ('ALSA: firewire-motu: postpone sound card registration') at v4.12
Fixes: b610386c8a ('ALSA: firewire-tascam: deleyed registration of sound card') at v4.7
Fixes: 86c8dd7f4d ('ALSA: firewire-digi00x: delayed registration of sound card') at v4.7
Fixes: 6c29230e2a ('ALSA: oxfw: delayed registration of sound card') at v4.7
Fixes: 7d3c1d5901 ('ALSA: fireworks: delayed registration of sound card') at v4.7
Fixes: 04a2c73c97 ('ALSA: bebob: delayed registration of sound card') at v4.7
Fixes: b59fb1900b ('ALSA: dice: postpone card registration') at v4.5
Cc: <stable@vger.kernel.org> # v4.5+
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Sakamoto 2017-08-20 15:54:26 +09:00 committed by Takashi Iwai
parent 0b36f2bd28
commit 0c264af7be
1 changed files with 6 additions and 1 deletions

View File

@ -210,9 +210,14 @@ EXPORT_SYMBOL(fw_iso_resources_update);
*/
void fw_iso_resources_free(struct fw_iso_resources *r)
{
struct fw_card *card = fw_parent_device(r->unit)->card;
struct fw_card *card;
int bandwidth, channel;
/* Not initialized. */
if (r->unit == NULL)
return;
card = fw_parent_device(r->unit)->card;
mutex_lock(&r->mutex);
if (r->allocated) {