[mod_auth] skip blank lines and comment lines (fixes #2327)

x-ref:
  "Ignore comments and empty lines in ht{digest,passwd} files"
  https://redmine.lighttpd.net/issues/2327

src/http_auth.c

@@ -86,6 +86,9 @@ static int http_auth_get_password(server *srv, mod_auth_plugin_data *p, buffer *
 			char *f_pwd, *f_realm;
 			size_t u_len, r_len;
 
+			/* skip blank lines and comment lines (beginning '#') */
+			if (f_user[0] == '#' || f_user[0] == '\n' || f_user[0] == '\0') continue;
+
 			/*
 			 * htdigest format
 			 *
@@ -153,6 +156,9 @@ static int http_auth_get_password(server *srv, mod_auth_plugin_data *p, buffer *
 			char *f_pwd;
 			size_t u_len;
 
+			/* skip blank lines and comment lines (beginning '#') */
+			if (f_user[0] == '#' || f_user[0] == '\n' || f_user[0] == '\0') continue;
+
 			/*
 			 * htpasswd format
 			 *

tests/lighttpd.htpasswd

@@ -1,4 +1,6 @@
+# some comment
 des:12tMnfw882VDQ
+
 md5:$1$md5$kIa7Juuiv8zja0ILQPR36/
 sha:{SHA}2PRZAyDhNDqRW2OUFwZQqPNdaSY=
 apr-md5:$apr1$w2kLqmDN$uMe8ZCfMRT81wf43Y1hny0