res_stir_shaken.c: Fix crash when stir_shaken.conf is invalid

* If the call to ast_config_load() returns CONFIG_STATUS_FILEINVALID,
check_for_old_config() now returns LOAD_DECLINE instead of continuing
on with a bad pointer.

* If CONFIG_STATUS_FILEMISSING is returned, check_for_old_config()
assumes the config is being loaded from realtime and now returns
LOAD_SUCCESS.  If it's actually not being loaded from realtime,
sorcery will catch that later on.

* Also refactored the error handling in load_module() a bit.

Resolves: #884

diff --git a/res/res_stir_shaken.c b/res/res_stir_shaken.c
index 4e268508bf710c249169c1f7cfdb410d1ba44d24..2405ee527f498241467423ec66e31d578f0c886d 100644 (file)
--- a/res/res_stir_shaken.c
+++ b/res/res_stir_shaken.c
@@ -311,13 +311,22 @@ static int check_for_old_config(void)
        char *cat = NULL;
 
        cfg = ast_config_load("stir_shaken.conf", config_flags);
-       if (cfg == NULL) {
+       if (cfg == CONFIG_STATUS_FILEMISSING) {
                /*
                 * They may be loading from realtime so the fact that there's
                 * no stir-shaken.conf file isn't an issue for this purpose.
                 */
+               return AST_MODULE_LOAD_SUCCESS;
+       } else if (cfg == CONFIG_STATUS_FILEINVALID) {
+               cfg = NULL;
+               ast_log(LOG_ERROR, "The stir_shaken.conf file is invalid\n");
                return AST_MODULE_LOAD_DECLINE;
+       } else if (cfg == CONFIG_STATUS_FILEUNCHANGED) {
+               /* This can never happen but is included for completeness */
+               cfg = NULL;
+               return AST_MODULE_LOAD_SUCCESS;
        }
+
        while ((cat = ast_category_browse(cfg, cat))) {
                const char *val;
                if (strcasecmp(cat, "general") == 0) {
@@ -339,13 +348,14 @@ static int load_module(void)
 {
        int res = 0;
 
-       if (check_for_old_config()) {
-               return AST_MODULE_LOAD_DECLINE;
+       res = check_for_old_config();
+       if (res != AST_MODULE_LOAD_SUCCESS) {
+               return res;
        }
 
-       if (crypto_load()) {
-               unload_module();
-               return AST_MODULE_LOAD_DECLINE;
+       res = crypto_load();
+       if (res != AST_MODULE_LOAD_SUCCESS) {
+               return res;
        }
 
        tn_auth_list_nid = crypto_register_x509_extension(TN_AUTH_LIST_OID,
@@ -355,14 +365,19 @@ static int load_module(void)
                return AST_MODULE_LOAD_DECLINE;
        }
 
-       if (common_config_load()) {
+       res = common_config_load();
+       if (res != AST_MODULE_LOAD_SUCCESS) {
                unload_module();
-               return AST_MODULE_LOAD_DECLINE;
+               return res;
        }
 
-       res |= ast_custom_function_register(&stir_shaken_function);
+       res = ast_custom_function_register(&stir_shaken_function);
+       if (res != 0) {
+               unload_module();
+               return AST_MODULE_LOAD_DECLINE;
+       }
 
-       return res;
+       return AST_MODULE_LOAD_SUCCESS;
 }
 
 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "STIR/SHAKEN Module for Asterisk",