fix: usr: Unknown directive in resolv.conf not handled properly

The line after an unknown directive in resolv.conf could accidentally be skipped, potentially affecting dig, host, nslookup, nsupdate, or delv. This has been fixed.

Closes #5084

Merge branch '5084-plain-unknown-keyword-in-resolv-conf-not-handled-propely' into 'main'

See merge request isc-projects/bind9!9865

lib/dns/resconf.c

@@ -585,9 +585,11 @@ irs_resconf_load(isc_mem_t *mctx, const char *filename, irs_resconf_t **confp) {
 			} else {
 				/* unrecognised word. Ignore entire line */
 				rval = ISC_R_SUCCESS;
-				stopchar = eatline(fp);
-				if (stopchar == EOF) {
-					break;
+				if (stopchar != '\n') {
+					stopchar = eatline(fp);
+					if (stopchar == EOF) {
+						break;
+					}
 				}
 			}
 			if (ret == ISC_R_SUCCESS && rval != ISC_R_SUCCESS) {

tests/irs/resconf_test.c

@@ -11,8 +11,6 @@
  * information regarding copyright ownership.
  */
 
-#if HAVE_CMOCKA
-
 #include <inttypes.h>
 #include <sched.h> /* IWYU pragma: keep */
 #include <setjmp.h>
@@ -31,19 +29,7 @@
 
 #include <irs/resconf.h>
 
-static isc_mem_t *mctx = NULL;
-
-static void
-setup_test(void) {
-	isc_mem_create(&mctx);
-
-	/*
-	 * the caller might run from another directory, but tests
-	 * that access test data files must first chdir to the proper
-	 * location.
-	 */
-	assert_return_code(chdir(TESTS_DIR), 0);
-}
+#include <tests/isc.h>
 
 static isc_result_t
 check_number(unsigned int n, unsigned int expected) {
@@ -65,6 +51,24 @@ check_ndots(irs_resconf_t *resconf) {
 	return check_number(irs_resconf_getndots(resconf), 2);
 }
 
+static isc_result_t
+search_example(irs_resconf_t *resconf) {
+	irs_resconf_search_t *entry;
+	irs_resconf_searchlist_t *list;
+	list = irs_resconf_getsearchlist(resconf);
+	if (list == NULL) {
+		return ISC_R_NOTFOUND;
+	}
+	entry = ISC_LIST_HEAD(*list);
+	assert_true(entry != NULL && entry->domain != NULL);
+	assert_string_equal(entry->domain, "example.com");
+
+	entry = ISC_LIST_TAIL(*list);
+	assert_true(entry != NULL && entry->domain != NULL);
+	assert_string_equal(entry->domain, "example.net");
+	return ISC_R_SUCCESS;
+}
+
 static isc_result_t
 check_options(irs_resconf_t *resconf) {
 	if (irs_resconf_getattempts(resconf) != 3) {
@@ -83,8 +87,7 @@ check_options(irs_resconf_t *resconf) {
 }
 
 /* test irs_resconf_load() */
-static void
-irs_resconf_load_test(void **state) {
+ISC_RUN_TEST_IMPL(irs_resconf_load) {
 	isc_result_t result;
 	irs_resconf_t *resconf = NULL;
 	unsigned int i;
@@ -119,18 +122,27 @@ irs_resconf_load_test(void **state) {
 		  ISC_R_SUCCESS },
 		{ "testdata/port.conf", ISC_R_SUCCESS, NULL, ISC_R_SUCCESS },
 		{ "testdata/resolv.conf", ISC_R_SUCCESS, NULL, ISC_R_SUCCESS },
-		{ "testdata/search.conf", ISC_R_SUCCESS, NULL, ISC_R_SUCCESS },
+		{ "testdata/search.conf", ISC_R_SUCCESS, search_example,
+		  ISC_R_SUCCESS },
 		{ "testdata/sortlist-v4.conf", ISC_R_SUCCESS, NULL,
 		  ISC_R_SUCCESS },
 		{ "testdata/timeout.conf", ISC_R_SUCCESS, NULL, ISC_R_SUCCESS },
-		{ "testdata/unknown.conf", ISC_R_SUCCESS, NULL, ISC_R_SUCCESS }
+		{ "testdata/unknown-with-value.conf", ISC_R_SUCCESS, NULL,
+		  ISC_R_SUCCESS },
+		{ "testdata/unknown-without-value.conf", ISC_R_SUCCESS, NULL,
+		  ISC_R_SUCCESS },
+		{ "testdata/unknown+search.conf", ISC_R_SUCCESS, search_example,
+		  ISC_R_SUCCESS }
 	};
 
 	UNUSED(state);
 
-	setup_test();
+	assert_return_code(chdir(TESTS_DIR), 0);
 
 	for (i = 0; i < sizeof(tests) / sizeof(tests[1]); i++) {
+		if (debug) {
+			fprintf(stderr, "# testing '%s'\n", tests[i].file);
+		}
 		result = irs_resconf_load(mctx, tests[i].file, &resconf);
 		if (result != tests[i].loadres) {
 			fail_msg("# unexpected result %s loading %s",
@@ -156,27 +168,10 @@ irs_resconf_load_test(void **state) {
 			irs_resconf_destroy(&resconf);
 		}
 	}
-
-	isc_mem_detach(&mctx);
 }
 
-int
-main(void) {
-	const struct CMUnitTest tests[] = {
-		cmocka_unit_test(irs_resconf_load_test),
-	};
+ISC_TEST_LIST_START
+ISC_TEST_ENTRY(irs_resconf_load)
+ISC_TEST_LIST_END
 
-	return cmocka_run_group_tests(tests, NULL, NULL);
-}
-
-#else /* HAVE_CMOCKA */
-
-#include <stdio.h>
-
-int
-main(void) {
-	printf("1..0 # Skipped: cmocka not available\n");
-	return SKIPPED_TEST_EXIT_CODE;
-}
-
-#endif /* if HAVE_CMOCKA */
+ISC_TEST_MAIN

tests/irs/testdata/unknown+search.conf

@@ -0,0 +1,13 @@
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+unknown
+search example.com example.net

tests/irs/testdata/unknown-without-value.conf

@@ -0,0 +1,12 @@
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+unknown