ALSA: ac97: Fix possible error value of *rac97

[PATCH] ALSA: ac97: Fix possible error value of *rac97

Posted by Su Hui 2 years, 3 months ago

Before committing 79597c8bf64c, *rac97 always be NULL if there is
an error. When error happens, make sure *rac97 is NULL is safer.

For examble, in snd_vortex_mixer():
	err = snd_ac97_mixer(pbus, &ac97, &vortex->codec);
	vortex->isquad = ((vortex->codec == NULL) ?
		0 : (vortex->codec->ext_id&0x80));
If error happened but vortex->codec isn't NULL, this may cause some
problems.

Move the judgement order to be clearer and better.

Fixes: 79597c8bf64c ("ALSA: ac97: Fix possible NULL dereference in snd_ac97_mixer")
Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Su Hui <suhui@nfschina.com>
---
 sound/pci/ac97/ac97_codec.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
index 80a65b8ad7b9..25f93e56cfc7 100644
--- a/sound/pci/ac97/ac97_codec.c
+++ b/sound/pci/ac97/ac97_codec.c
@@ -2069,10 +2069,9 @@ int snd_ac97_mixer(struct snd_ac97_bus *bus, struct snd_ac97_template *template,
 		.dev_disconnect =	snd_ac97_dev_disconnect,
 	};
 
-	if (!rac97)
-		return -EINVAL;
-	if (snd_BUG_ON(!bus || !template))
+	if (snd_BUG_ON(!bus || !template || !rac97))
 		return -EINVAL;
+	*rac97 = NULL;
 	if (snd_BUG_ON(template->num >= 4))
 		return -EINVAL;
 	if (bus->codec[template->num])
-- 
2.30.2

Re: [PATCH] ALSA: ac97: Fix possible error value of *rac97

Posted by Christophe JAILLET 2 years, 3 months ago

Le 23/08/2023 à 04:52, Su Hui a écrit :
> Before committing 79597c8bf64c, *rac97 always be NULL if there is
> an error. When error happens, make sure *rac97 is NULL is safer.
> 
> For examble, in snd_vortex_mixer():
> 	err = snd_ac97_mixer(pbus, &ac97, &vortex->codec);
> 	vortex->isquad = ((vortex->codec == NULL) ?
> 		0 : (vortex->codec->ext_id&0x80));
> If error happened but vortex->codec isn't NULL, this may cause some
> problems.
> 
> Move the judgement order to be clearer and better.
> 
> Fixes: 79597c8bf64c ("ALSA: ac97: Fix possible NULL dereference in snd_ac97_mixer")
> Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Signed-off-by: Su Hui <suhui@nfschina.com>
> ---
>   sound/pci/ac97/ac97_codec.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
> index 80a65b8ad7b9..25f93e56cfc7 100644
> --- a/sound/pci/ac97/ac97_codec.c
> +++ b/sound/pci/ac97/ac97_codec.c
> @@ -2069,10 +2069,9 @@ int snd_ac97_mixer(struct snd_ac97_bus *bus, struct snd_ac97_template *template,
>   		.dev_disconnect =	snd_ac97_dev_disconnect,
>   	};
>   
> -	if (!rac97)
> -		return -EINVAL;
> -	if (snd_BUG_ON(!bus || !template))
> +	if (snd_BUG_ON(!bus || !template || !rac97))
>   		return -EINVAL;
> +	*rac97 = NULL;
>   	if (snd_BUG_ON(template->num >= 4))
>   		return -EINVAL;
>   	if (bus->codec[template->num])

FWIW,

Acked-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

CJ

Re: [PATCH] ALSA: ac97: Fix possible error value of *rac97

Posted by Takashi Iwai 2 years, 3 months ago

On Wed, 23 Aug 2023 19:20:49 +0200,
Christophe JAILLET wrote:
> 
> Le 23/08/2023 à 04:52, Su Hui a écrit :
> > Before committing 79597c8bf64c, *rac97 always be NULL if there is
> > an error. When error happens, make sure *rac97 is NULL is safer.
> > 
> > For examble, in snd_vortex_mixer():
> > 	err = snd_ac97_mixer(pbus, &ac97, &vortex->codec);
> > 	vortex->isquad = ((vortex->codec == NULL) ?
> > 		0 : (vortex->codec->ext_id&0x80));
> > If error happened but vortex->codec isn't NULL, this may cause some
> > problems.
> > 
> > Move the judgement order to be clearer and better.
> > 
> > Fixes: 79597c8bf64c ("ALSA: ac97: Fix possible NULL dereference in snd_ac97_mixer")
> > Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > Signed-off-by: Su Hui <suhui@nfschina.com>
> > ---
> >   sound/pci/ac97/ac97_codec.c | 5 ++---
> >   1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
> > index 80a65b8ad7b9..25f93e56cfc7 100644
> > --- a/sound/pci/ac97/ac97_codec.c
> > +++ b/sound/pci/ac97/ac97_codec.c
> > @@ -2069,10 +2069,9 @@ int snd_ac97_mixer(struct snd_ac97_bus *bus, struct snd_ac97_template *template,
> >   		.dev_disconnect =	snd_ac97_dev_disconnect,
> >   	};
> >   -	if (!rac97)
> > -		return -EINVAL;
> > -	if (snd_BUG_ON(!bus || !template))
> > +	if (snd_BUG_ON(!bus || !template || !rac97))
> >   		return -EINVAL;
> > +	*rac97 = NULL;
> >   	if (snd_BUG_ON(template->num >= 4))
> >   		return -EINVAL;
> >   	if (bus->codec[template->num])
> 
> FWIW,
> 
> Acked-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

Applied now, thanks.


Takashi