[alsa-devel] [PATCH] ASoC: core: Fix use-after-free after deferred card registration
If snd_soc_register_card() fails because one of its links fails to instantiate with -EPROBE_DEFER, and the to-be-registered link is a legacy link, a subsequent retry will trigger a use-after-free and quite often a system crash.
Example:
byt-max98090 byt-max98090: ASoC: failed to init link Baytrail Audio byt-max98090 byt-max98090: snd_soc_register_card failed -517 .... BUG: KASAN: use-after-free in snd_soc_init_platform+0x233/0x312 Read of size 8 at addr ffff888067c43070 by task kworker/1:1/23
snd_soc_init_platform() allocates memory attached to the card device. This memory is released when the card device is released. However, the pointer to the memory (dai_link->platforms) is only cleared from soc_cleanup_platform(), which is called from soc_cleanup_card_resources(), but not if snd_soc_register_card() fails early.
Add the missing call to soc_cleanup_platform() in the error handling code of snd_soc_register_card() to fix the problem.
Fixes: 78a24e10cd94 ("ASoC: soc-core: clear platform pointers on error") Cc: Curtis Malainey cujomalainey@chromium.org Signed-off-by: Guenter Roeck linux@roeck-us.net --- sound/soc/soc-core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 93d316d5bf8e..6bf9884d0863 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -2799,6 +2799,7 @@ int snd_soc_register_card(struct snd_soc_card *card) if (ret) { dev_err(card->dev, "ASoC: failed to init link %s\n", link->name); + soc_cleanup_platform(card); mutex_unlock(&client_mutex); return ret; }
This has already been patched. See https://mailman.alsa-project.org/pipermail/alsa-devel/2019-March/146150.html
On Tue, Mar 26, 2019 at 10:23 AM Guenter Roeck linux@roeck-us.net wrote:
If snd_soc_register_card() fails because one of its links fails to instantiate with -EPROBE_DEFER, and the to-be-registered link is a legacy link, a subsequent retry will trigger a use-after-free and quite often a system crash.
Example:
byt-max98090 byt-max98090: ASoC: failed to init link Baytrail Audio byt-max98090 byt-max98090: snd_soc_register_card failed -517 .... BUG: KASAN: use-after-free in snd_soc_init_platform+0x233/0x312 Read of size 8 at addr ffff888067c43070 by task kworker/1:1/23
snd_soc_init_platform() allocates memory attached to the card device. This memory is released when the card device is released. However, the pointer to the memory (dai_link->platforms) is only cleared from soc_cleanup_platform(), which is called from soc_cleanup_card_resources(), but not if snd_soc_register_card() fails early.
Add the missing call to soc_cleanup_platform() in the error handling code of snd_soc_register_card() to fix the problem.
Fixes: 78a24e10cd94 ("ASoC: soc-core: clear platform pointers on error") Cc: Curtis Malainey cujomalainey@chromium.org Signed-off-by: Guenter Roeck linux@roeck-us.net
sound/soc/soc-core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 93d316d5bf8e..6bf9884d0863 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -2799,6 +2799,7 @@ int snd_soc_register_card(struct snd_soc_card *card) if (ret) { dev_err(card->dev, "ASoC: failed to init link %s\n", link->name);
soc_cleanup_platform(card); mutex_unlock(&client_mutex); return ret; }-- 2.7.4
On Tue, Mar 26, 2019 at 10:35:41AM -0700, Curtis Malainey wrote:
This has already been patched. See https://mailman.alsa-project.org/pipermail/alsa-devel/2019-March/146150.html
Ah, obviously. I missed that one. Sorry for the noise.
Guenter
On Tue, Mar 26, 2019 at 10:23 AM Guenter Roeck linux@roeck-us.net wrote:
If snd_soc_register_card() fails because one of its links fails to instantiate with -EPROBE_DEFER, and the to-be-registered link is a legacy link, a subsequent retry will trigger a use-after-free and quite often a system crash.
Example:
byt-max98090 byt-max98090: ASoC: failed to init link Baytrail Audio byt-max98090 byt-max98090: snd_soc_register_card failed -517 .... BUG: KASAN: use-after-free in snd_soc_init_platform+0x233/0x312 Read of size 8 at addr ffff888067c43070 by task kworker/1:1/23
snd_soc_init_platform() allocates memory attached to the card device. This memory is released when the card device is released. However, the pointer to the memory (dai_link->platforms) is only cleared from soc_cleanup_platform(), which is called from soc_cleanup_card_resources(), but not if snd_soc_register_card() fails early.
Add the missing call to soc_cleanup_platform() in the error handling code of snd_soc_register_card() to fix the problem.
Fixes: 78a24e10cd94 ("ASoC: soc-core: clear platform pointers on error") Cc: Curtis Malainey cujomalainey@chromium.org Signed-off-by: Guenter Roeck linux@roeck-us.net
sound/soc/soc-core.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 93d316d5bf8e..6bf9884d0863 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -2799,6 +2799,7 @@ int snd_soc_register_card(struct snd_soc_card *card) if (ret) { dev_err(card->dev, "ASoC: failed to init link %s\n", link->name);
soc_cleanup_platform(card); mutex_unlock(&client_mutex); return ret; }-- 2.7.4
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Guenter Roeck