[PATCH 4.9 302/329] ALSA: vmaster: Propagate slave error

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 06:39:55 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@xxxxxxx>

[ Upstream commit 2e2c177ca84aff092c3c96714b0f6a12900f3946 ]

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@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/core/vmaster.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -68,10 +68,13 @@ static int slave_update(struct link_slav
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 */