[PATCH 3.12 047/155] ALSA: control: Add sanity checks for user ctl id name string

From: Jiri Slaby
Date: Tue Apr 07 2015 - 09:28:20 EST

From: Takashi Iwai <tiwai@xxxxxxx>

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


commit be3bb8236db2d0fcd705062ae2e2a9d75131222f upstream.

There was no check about the id string of user control elements, so we
accepted even a control element with an empty string, which is
obviously bogus. This patch adds more sanity checks of id strings.

Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
sound/core/control.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/sound/core/control.c b/sound/core/control.c
index 98a29b26c5f4..f2082a35b890 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1168,6 +1168,10 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,

if (info->count < 1)
return -EINVAL;
+ if (!*info->id.name)
+ return -EINVAL;
+ if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
+ return -EINVAL;
access = info->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :

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