From 0c264af7be2013266c5b4c644f3f366399ee490a Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Sun, 20 Aug 2017 15:54:26 +0900
Subject: [PATCH] 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: 324540c4e05c ('ALSA: fireface: postpone sound card registration') at v4.12
Fixes: 8865a31e0fd8 ('ALSA: firewire-motu: postpone sound card registration') at v4.12
Fixes: b610386c8afb ('ALSA: firewire-tascam: deleyed registration of sound card') at v4.7
Fixes: 86c8dd7f4da3 ('ALSA: firewire-digi00x: delayed registration of sound card') at v4.7
Fixes: 6c29230e2a5f ('ALSA: oxfw: delayed registration of sound card') at v4.7
Fixes: 7d3c1d5901aa ('ALSA: fireworks: delayed registration of sound card') at v4.7
Fixes: 04a2c73c97eb ('ALSA: bebob: delayed registration of sound card') at v4.7
Fixes: b59fb1900b4f ('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>
---
sound/firewire/iso-resources.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/sound/firewire/iso-resources.c b/sound/firewire/iso-resources.c
index f0e4d502d6048..066b5df666f42 100644
--- a/sound/firewire/iso-resources.c
+++ b/sound/firewire/iso-resources.c
@@ -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) {
--
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