test-env-util: Verify that \r is disallowed in env var values

This adds tests to make sure that basic/env-util considers environment
variables containing \r characters invalid, and that it removes such
variables during environment cleanup in strv_env_clean*().

test-env-util has not verified this behaviour before.

As \r characters can be used to hide information, disallowing them
helps with systemd's security barrier role, even when the \r
character comes as part of a DOS style (\r\n) line ending.

Prompted-by: https://github.com/systemd/systemd/issues/17378

diff --git a/src/test/test-env-util.c b/src/test/test-env-util.c
index b0af660e3bad5861aecacc324efd6cafacca5e77..4fede158cd075eb9a403d4cd743052b0894e5285 100644 (file)
--- a/src/test/test-env-util.c
+++ b/src/test/test-env-util.c
@@ -264,6 +264,7 @@ static void test_env_clean(void) {
                                                 "xyz=xyz\n",
                                                 "another=one",
                                                 "another=final one",
+                                                "CRLF=\r\n",
                                                 "BASH_FUNC_foo%%=() {  echo foo\n}");
         assert_se(e);
         assert_se(!strv_env_is_valid(e));
@@ -306,6 +307,8 @@ static void test_env_value_is_valid(void) {
         assert_se(env_value_is_valid("printf \"\\x1b]0;<mock-chroot>\\x07<mock-chroot>\""));
         assert_se(env_value_is_valid("tab\tcharacter"));
         assert_se(env_value_is_valid("new\nline"));
+        assert_se(!env_value_is_valid("Show this?\rNope. Show that!"));
+        assert_se(!env_value_is_valid("new DOS\r\nline"));
 }
 
 static void test_env_assignment_is_valid(void) {