[RFC v2] ALSA: control: fix a error handling exist in snd_ctl_elem_add

[yangerkun]

CVE-2020-11725 report that 'count = info->owner' may result a
SIZE_OVERFLOW. 'info->owner' represent a pid, and actually, we should
use info->count.

Signed-off-by: yangerkun <yangerkun at huawei.com>
---
 sound/core/control.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

v1->v2: reword the patch head

diff --git a/sound/core/control.c b/sound/core/control.c
index aa0c0cf182af..c77ca7f39637 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1431,7 +1431,7 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
 		return -ENOMEM;
 
 	/* Check the number of elements for this userspace control. */
-	count = info->owner;
+	count = info->count;
 	if (count == 0)
 		count = 1;
 
-- 
2.21.1