mod_session_dbd: set_cookie_name: ensure correct format

If args is an empty string, apr_strtok will return NULL and *last will never get set which results in a SIGSEGV in apr_isspace check

Author: thomasmey

modules/session/mod_session_dbd.c

@@ -571,6 +571,9 @@ static const char *set_cookie_name(cmd_parms * cmd, void *config, const char *ar
     char *line = apr_pstrdup(cmd->pool, args);
     session_dbd_dir_conf *conf = (session_dbd_dir_conf *) config;
     char *cookie = apr_strtok(line, " \t", &last);
+    if(!cookie) {
+        return "Invalid directive, skipping";
+    }
     conf->name = cookie;
     conf->name_set = 1;
     while (apr_isspace(*last)) {
@@ -586,6 +589,9 @@ static const char *set_cookie_name2(cmd_parms * cmd, void *config, const char *a
     char *line = apr_pstrdup(cmd->pool, args);
     session_dbd_dir_conf *conf = (session_dbd_dir_conf *) config;
     char *cookie = apr_strtok(line, " \t", &last);
+    if(!cookie) {
+        return "Invalid directive, skipping";
+    }
     conf->name2 = cookie;
     conf->name2_set = 1;
     while (apr_isspace(*last)) {