ALSA: vmaster: Propagate slave error

BugLink: http://bugs.launchpad.net/bugs/1786352
[ 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@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index 8632301489fa66e9973b40330ac28a75026c20af..b67de2bb06a2f3ac6953ca13b8c22e43511a8d78 100644 (file)
--- 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 */