UCM: Disallow gets of undefined system properties

In UCM, there are various system-defined properties whose names start
with "_". Explicitly prevent any gets from falling back to properties
defined in a config file if the property name starts with "_", in order
to reserve the entire "_" namespace for system-defined properties.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/ucm/main.c b/src/ucm/main.c
index e5d06e6e92b3f3938394d52cf144153c1808f8cf..d319160c53e34b6c3bd3588c0aab8bb77b4730a8 100644 (file)
--- a/src/ucm/main.c
+++ b/src/ucm/main.c
@@ -1032,6 +1032,8 @@ int snd_use_case_get_list(snd_use_case_mgr_t *uc_mgr,
                        err = get_device_list(uc_mgr, list, str);
                 else if (check_identifier(identifier, "_modifiers"))
                         err = get_modifier_list(uc_mgr, list, str);
+               else if (identifier[0] == '_')
+                       err = -ENOENT;
                 else
                         err = get_value_list(uc_mgr, identifier, list, str);
                if (str)
@@ -1159,6 +1161,9 @@ int snd_use_case_get(snd_use_case_mgr_t *uc_mgr,
                         goto __end;
                 }
                err = 0;
+       } else if (identifier[0] == '_') {
+               err = -ENOENT;
+               goto __end;
         } else {
                 str1 = strchr(identifier, '/');
                 if (str1) {
@@ -1247,8 +1252,16 @@ int snd_use_case_geti(snd_use_case_mgr_t *uc_mgr,
                                *value = err;
                                err = 0;
                        }
+#if 0
+               /*
+                * enable this block if the else clause below is expanded to query
+                * user-supplied values
+                */
+               } else if (identifier[0] == '_')
+                       err = -ENOENT;
+#endif
                } else
-                        err = -EINVAL;
+                        err = -ENOENT;
                 if (str)
                         free(str);
         }