[patch] Fix snd-usb-audio in 32-bit compat environemt

[Juergen Kreileder <jk@blackdown.de>]

Hi,

I'm getting oopses with snd-usb-audio in 32-bit compat environments:
control_compat.c:get_ctl_type() doesn't initialize 'info', so
'itemlist[uinfo->value.enumerated.item]' in
usbmixer.c:mixer_ctl_selector_info() might access random memory
(The 'if ((int)uinfo->value.enumerated.item >= cval->max)' doesn't fix
all problems because of the unsigned -> signed conversion.)

Here's a fix:

Signed-off-by: Juergen Kreileder <jk@blackdown.de>

--- linux-mm-vanilla/sound/core/control_compat.c	2006-02-18 17:00:17.000000000 +0100
+++ linux-mm/sound/core/control_compat.c	2006-02-18 19:17:45.000000000 +0100
@@ -167,7 +167,7 @@ static int get_ctl_type(struct snd_card 
 			int *countp)
 {
 	struct snd_kcontrol *kctl;
-	struct snd_ctl_elem_info info;
+	struct snd_ctl_elem_info *info;
 	int err;
 
 	down_read(&card->controls_rwsem);
@@ -176,13 +176,19 @@ static int get_ctl_type(struct snd_card 
 		up_read(&card->controls_rwsem);
 		return -ENXIO;
 	}
-	info.id = *id;
-	err = kctl->info(kctl, &info);
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (info == NULL) {
+		up_read(&card->controls_rwsem);
+		return -ENOMEM;
+	}
+	info->id = *id;
+	err = kctl->info(kctl, info);
 	up_read(&card->controls_rwsem);
 	if (err >= 0) {
-		err = info.type;
-		*countp = info.count;
+		err = info->type;
+		*countp = info->count;
 	}
+	kfree(info);
 	return err;
 }
 
=

Tested on ppc64.


        Juergen

-- 
Juergen Kreileder, Blackdown Java-Linux Team
http://blog.blackdown.de/
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