From: Mark Andrews <marka@isc.org>
Date: Tue, 19 May 2026 00:44:04 +0000 (+1000)
Subject: Check that dns_name_fromwire honours the active region
X-Git-Tag: v9.21.24~13^2~8
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3ed821d68b15fe4e6288e3054397d6bce7e65968;p=thirdparty%2Fbind9.git

Check that dns_name_fromwire honours the active region

When reading DNS records from the wire the active region of the
source buffer is set to the end of the current record. dns_name_fromwire
should fail if it attempts to read past this setting.
---

diff --git a/tests/dns/name_test.c b/tests/dns/name_test.c
index dab4bbb4c94..f9a0dcf2e11 100644
--- a/tests/dns/name_test.c
+++ b/tests/dns/name_test.c
@@ -534,6 +534,32 @@ ISC_RUN_TEST_IMPL(fromregion) {
 	assert_false(dns_name_isabsolute(&name));
 }
 
+ISC_RUN_TEST_IMPL(fromwire) {
+	dns_fixedname_t fixed;
+	dns_name_t *name = dns_fixedname_initname(&fixed);
+	isc_buffer_t b;
+	unsigned char source[] = { 0x03, 'o', 'n', 'e',	 0x00, 0x03,
+				   't',	 'w', 'o', 0x00, 0x05, 't',
+				   'h',	 'r', 'e', 'e',	 0x00 };
+	isc_result_t result;
+
+	isc_buffer_init(&b, source, sizeof(source));
+	isc_buffer_add(&b, sizeof(source));
+	isc_buffer_setactive(&b, 10); /* names 'one.' and 'two.' */
+
+	/*
+	 * We should only be able to read two names from the buffer
+	 * as the active region has been set to cover only the first
+	 * two.
+	 */
+	result = dns_name_fromwire(name, &b, DNS_DECOMPRESS_NEVER, NULL);
+	assert_int_equal(result, ISC_R_SUCCESS);
+	result = dns_name_fromwire(name, &b, DNS_DECOMPRESS_NEVER, NULL);
+	assert_int_equal(result, ISC_R_SUCCESS);
+	result = dns_name_fromwire(name, &b, DNS_DECOMPRESS_NEVER, NULL);
+	assert_int_not_equal(result, ISC_R_SUCCESS);
+}
+
 /* is trust-anchor-telemetry test */
 ISC_RUN_TEST_IMPL(istat) {
 	dns_fixedname_t fixed;
@@ -1015,6 +1041,7 @@ ISC_TEST_ENTRY(fullcompare)
 ISC_TEST_ENTRY(compression)
 ISC_TEST_ENTRY(collision)
 ISC_TEST_ENTRY(fromregion)
+ISC_TEST_ENTRY(fromwire)
 ISC_TEST_ENTRY(istat)
 ISC_TEST_ENTRY(init)
 ISC_TEST_ENTRY(invalidate)