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 24d9510ecfec44fbd0effd97605f38d3551d29d5..8cc92089a326aad945353a2ceaaad8918a9f7730 100644 (file)
--- 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;