[alsa-devel] [PATCH 1/2] ALSA: vmaster: Propagate slave error
In slave_update() of vmaster code ignores the error from the slave get() callback and copies the values. It's not only about the missing error code but also that this may potentially lead to a leak of uninitialized variables when the slave get() don't clear them.
This patch fixes slave_update() not to copy the potentially uninitialized values when an error is returned from the slave get() callback, and to propagate the error value properly.
Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/vmaster.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c index 8632301489fa..b67de2bb06a2 100644 --- a/sound/core/vmaster.c +++ b/sound/core/vmaster.c @@ -68,10 +68,13 @@ static int slave_update(struct link_slave *slave) return -ENOMEM; uctl->id = slave->slave.id; err = slave->slave.get(&slave->slave, uctl); + if (err < 0) + goto error; for (ch = 0; ch < slave->info.count; ch++) slave->vals[ch] = uctl->value.integer.value[ch]; + error: kfree(uctl); - return 0; + return err < 0 ? err : 0; }
/* get the slave ctl info and save the initial values */
Use kzalloc() instead of kmalloc() so that we don't need to rely fully on the slave get() callback to clear the control value that might be copied to user-space.
Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/vmaster.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c index b67de2bb06a2..9e96186742d0 100644 --- a/sound/core/vmaster.c +++ b/sound/core/vmaster.c @@ -63,7 +63,7 @@ static int slave_update(struct link_slave *slave) struct snd_ctl_elem_value *uctl; int err, ch;
- uctl = kmalloc(sizeof(*uctl), GFP_KERNEL); + uctl = kzalloc(sizeof(*uctl), GFP_KERNEL); if (!uctl) return -ENOMEM; uctl->id = slave->slave.id;
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Takashi Iwai