From: Antonio Ospite <ao2@ao2.it>
Date: Fri, 23 Sep 2016 16:11:16 +0000 (+0200)
Subject: ucm: fix crash when calling snd_use_case_geti() with no device or modifier
X-Git-Tag: v1.1.3~58
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=4ec907c773a807d58b17f909522c27d05878b5b5;p=alsa-lib.git

ucm: fix crash when calling snd_use_case_geti() with no device or modifier

When calling snd_use_case_geti(uc_mgr, "_devstatus", &lvalue) the code
ends up calling device_status(uc_mgr, NULL), which result in a crash in
strcmp(dev->name, NULL), when there are enabled devices.

This happens because snd_use_case_geti() allows a "_devstatus"
identifier even if it's only supposed to allow the form
"_devstatus/{device}".

So check that the device name is not null.

The same issue occurs with "_modstatus", this change fixes that as well.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

diff --git a/src/ucm/main.c b/src/ucm/main.c
index 24d9510e..8cc92089 100644
--- a/src/ucm/main.c
+++ b/src/ucm/main.c
@@ -1528,12 +1528,20 @@ int snd_use_case_geti(snd_use_case_mgr_t *uc_mgr,
                         str = NULL;
                 }
                 if (check_identifier(identifier, "_devstatus")) {
+			if (!str) {
+				err = -EINVAL;
+				goto __end;
+			}
                         err = device_status(uc_mgr, str);
 			if (err >= 0) {
 				*value = err;
 				err = 0;
 			}
 		} else if (check_identifier(identifier, "_modstatus")) {
+			if (!str) {
+				err = -EINVAL;
+				goto __end;
+			}
                         err = modifier_status(uc_mgr, str);
 			if (err >= 0) {
 				*value = err;