tls: improve wildcard matching (#11921)

VERSION

@@ -1 +1 @@
-1.14.3
+1.14.4

docs/root/intro/version_history.rst

@@ -1,6 +1,10 @@
 Version history
 ---------------
 
+1.14.4 (July 7, 2020)
+=====================
+* tls: fixed a bug where wilcard matching for "\*.foo.com" also matched domains of the form "a.b.foo.com". This behavior can be temporarily reverted by setting runtime feature `envoy.reloadable_features.fix_wildcard_matching` to false.
+
 1.14.3 (June 30, 2020)
 ======================
 * buffer: fixed CVE-2020-12603 by avoiding fragmentation, and tracking of HTTP/2 data and control frames in the output buffer.

source/common/runtime/runtime_features.cc

@@ -35,6 +35,7 @@ constexpr const char* runtime_features[] = {
     "envoy.reloadable_features.new_http2_connection_pool_behavior",
     "envoy.deprecated_features.allow_deprecated_extension_names",
     "envoy.reloadable_features.ext_authz_http_service_enable_case_sensitive_string_matcher",
+    "envoy.reloadable_features.fix_wildcard_matching",
 };
 
 // This is a section for officially sanctioned runtime features which are too

source/extensions/transport_sockets/tls/BUILD

@@ -109,6 +109,7 @@ envoy_cc_library(
         "//source/common/common:utility_lib",
         "//source/common/network:address_lib",
         "//source/common/protobuf:utility_lib",
+        "//source/common/runtime:runtime_lib",
         "//source/common/stats:symbol_table_lib",
         "//source/extensions/transport_sockets/tls/private_key:private_key_manager_lib",
         "@envoy_api//envoy/admin/v3:pkg_cc_proto",

source/extensions/transport_sockets/tls/context_impl.cc

@@ -19,6 +19,7 @@
 #include "common/common/utility.h"
 #include "common/network/address_impl.h"
 #include "common/protobuf/utility.h"
+#include "common/runtime/runtime_impl.h"
 
 #include "extensions/transport_sockets/tls/utility.h"
 
@@ -696,7 +697,12 @@ bool ContextImpl::dnsNameMatch(const std::string& dns_name, const char* pattern)
   if (pattern_len > 1 && pattern[0] == '*' && pattern[1] == '.') {
     if (dns_name.length() > pattern_len - 1) {
       const size_t off = dns_name.length() - pattern_len + 1;
-      return dns_name.compare(off, pattern_len - 1, pattern + 1) == 0;
+      if (Runtime::runtimeFeatureEnabled("envoy.reloadable_features.fix_wildcard_matching")) {
+        return dns_name.substr(0, off).find('.') == std::string::npos &&
+               dns_name.compare(off, pattern_len - 1, pattern + 1) == 0;
+      } else {
+        return dns_name.compare(off, pattern_len - 1, pattern + 1) == 0;
+      }
     }
   }
 

test/extensions/transport_sockets/tls/BUILD

@@ -83,6 +83,7 @@ envoy_cc_test(
         "//test/mocks/ssl:ssl_mocks",
         "//test/test_common:environment_lib",
         "//test/test_common:simulated_time_system_lib",
+        "//test/test_common:test_runtime_lib",
         "@envoy_api//envoy/admin/v3:pkg_cc_proto",
         "@envoy_api//envoy/extensions/transport_sockets/tls/v3:pkg_cc_proto",
         "@envoy_api//envoy/type/matcher/v3:pkg_cc_proto",

test/extensions/transport_sockets/tls/context_impl_test.cc

@@ -24,6 +24,7 @@
 #include "test/mocks/ssl/mocks.h"
 #include "test/test_common/environment.h"
 #include "test/test_common/simulated_time_system.h"
+#include "test/test_common/test_runtime.h"
 #include "test/test_common/utility.h"
 
 #include "gtest/gtest.h"
@@ -48,6 +49,23 @@ class SslContextImplTest : public SslCertsTest {
 TEST_F(SslContextImplTest, TestDnsNameMatching) {
   EXPECT_TRUE(ContextImpl::dnsNameMatch("lyft.com", "lyft.com"));
   EXPECT_TRUE(ContextImpl::dnsNameMatch("a.lyft.com", "*.lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("a.b.lyft.com", "*.lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("foo.test.com", "*.lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("lyft.com", "*.lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("alyft.com", "*.lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("alyft.com", "*lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("lyft.com", "*lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("", "*lyft.com"));
+  EXPECT_FALSE(ContextImpl::dnsNameMatch("lyft.com", ""));
+}
+
+TEST_F(SslContextImplTest, TestDnsNameMatchingLegacy) {
+  TestScopedRuntime scoped_runtime;
+  Runtime::LoaderSingleton::getExisting()->mergeValues(
+      {{"envoy.reloadable_features.fix_wildcard_matching", "false"}});
+  EXPECT_TRUE(ContextImpl::dnsNameMatch("lyft.com", "lyft.com"));
+  EXPECT_TRUE(ContextImpl::dnsNameMatch("a.lyft.com", "*.lyft.com"));
+  // Legacy behavior
   EXPECT_TRUE(ContextImpl::dnsNameMatch("a.b.lyft.com", "*.lyft.com"));
   EXPECT_FALSE(ContextImpl::dnsNameMatch("foo.test.com", "*.lyft.com"));
   EXPECT_FALSE(ContextImpl::dnsNameMatch("lyft.com", "*.lyft.com"));
@@ -87,6 +105,32 @@ TEST_F(SslContextImplTest, TestMatchSubjectAltNameWildcardDNSMatched) {
   EXPECT_TRUE(ContextImpl::matchSubjectAltName(cert.get(), subject_alt_name_matchers));
 }
 
+TEST_F(SslContextImplTest, TestMultiLevelMatch) {
+  // san_multiple_dns_cert matches *.example.com
+  bssl::UniquePtr<X509> cert = readCertFromFile(TestEnvironment::substitute(
+      "{{ test_rundir "
+      "}}/test/extensions/transport_sockets/tls/test_data/san_multiple_dns_cert.pem"));
+  envoy::type::matcher::v3::StringMatcher matcher;
+  matcher.set_exact("foo.api.example.com");
+  std::vector<Matchers::StringMatcherImpl> subject_alt_name_matchers;
+  subject_alt_name_matchers.push_back(Matchers::StringMatcherImpl(matcher));
+  EXPECT_FALSE(ContextImpl::matchSubjectAltName(cert.get(), subject_alt_name_matchers));
+}
+
+TEST_F(SslContextImplTest, TestMultiLevelMatchLegacy) {
+  TestScopedRuntime scoped_runtime;
+  Runtime::LoaderSingleton::getExisting()->mergeValues(
+      {{"envoy.reloadable_features.fix_wildcard_matching", "false"}});
+  bssl::UniquePtr<X509> cert = readCertFromFile(TestEnvironment::substitute(
+      "{{ test_rundir "
+      "}}/test/extensions/transport_sockets/tls/test_data/san_multiple_dns_cert.pem"));
+  envoy::type::matcher::v3::StringMatcher matcher;
+  matcher.set_exact("foo.api.example.com");
+  std::vector<Matchers::StringMatcherImpl> subject_alt_name_matchers;
+  subject_alt_name_matchers.push_back(Matchers::StringMatcherImpl(matcher));
+  EXPECT_TRUE(ContextImpl::matchSubjectAltName(cert.get(), subject_alt_name_matchers));
+}
+
 TEST_F(SslContextImplTest, TestVerifySubjectAltNameURIMatched) {
   bssl::UniquePtr<X509> cert = readCertFromFile(TestEnvironment::substitute(
       "{{ test_rundir }}/test/extensions/transport_sockets/tls/test_data/san_uri_cert.pem"));
@@ -95,6 +139,25 @@ TEST_F(SslContextImplTest, TestVerifySubjectAltNameURIMatched) {
   EXPECT_TRUE(ContextImpl::verifySubjectAltName(cert.get(), verify_subject_alt_name_list));
 }
 
+TEST_F(SslContextImplTest, TestVerifySubjectAltMultiDomain) {
+  bssl::UniquePtr<X509> cert = readCertFromFile(TestEnvironment::substitute(
+      "{{ test_rundir "
+      "}}/test/extensions/transport_sockets/tls/test_data/san_multiple_dns_cert.pem"));
+  std::vector<std::string> verify_subject_alt_name_list = {"https://a.www.example.com"};
+  EXPECT_FALSE(ContextImpl::verifySubjectAltName(cert.get(), verify_subject_alt_name_list));
+}
+
+TEST_F(SslContextImplTest, TestVerifySubjectAltMultiDomainLegacy) {
+  TestScopedRuntime scoped_runtime;
+  Runtime::LoaderSingleton::getExisting()->mergeValues(
+      {{"envoy.reloadable_features.fix_wildcard_matching", "false"}});
+  bssl::UniquePtr<X509> cert = readCertFromFile(TestEnvironment::substitute(
+      "{{ test_rundir "
+      "}}/test/extensions/transport_sockets/tls/test_data/san_multiple_dns_cert.pem"));
+  std::vector<std::string> verify_subject_alt_name_list = {"https://a.www.example.com"};
+  EXPECT_TRUE(ContextImpl::verifySubjectAltName(cert.get(), verify_subject_alt_name_list));
+}
+
 TEST_F(SslContextImplTest, TestMatchSubjectAltNameURIMatched) {
   bssl::UniquePtr<X509> cert = readCertFromFile(TestEnvironment::substitute(
       "{{ test_rundir }}/test/extensions/transport_sockets/tls/test_data/san_uri_cert.pem"));