ssl: add support for multiple CAs for client certificates.

Partially fixes envoyproxy#1220.

Signed-off-by: Piotr Sikora <piotrsikora@google.com>

include/envoy/ssl/BUILD

@@ -11,6 +11,7 @@ envoy_package()
 envoy_cc_library(
     name = "connection_interface",
     hdrs = ["connection.h"],
+    external_deps = ["ssl"],
 )
 
 envoy_cc_library(

include/envoy/ssl/connection.h

@@ -4,6 +4,8 @@
 
 #include "envoy/common/pure.h"
 
+#include "openssl/ssl.h"
+
 namespace Envoy {
 namespace Ssl {
 
@@ -42,6 +44,11 @@ class Connection {
    *         certificate, or no SAN field, or no URI.
    **/
   virtual std::string uriSanPeerCertificate() PURE;
+
+  /**
+   * @return underlying SSL object for use with BoringSSL.
+   **/
+  virtual SSL* rawSslForTest() PURE;
 };
 
 } // namespace Ssl

source/common/ssl/BUILD

@@ -12,6 +12,7 @@ envoy_cc_library(
     name = "connection_lib",
     srcs = ["connection_impl.cc"],
     hdrs = ["connection_impl.h"],
+    external_deps = ["ssl"],
     deps = [
         ":context_lib",
         "//source/common/common:assert_lib",

source/common/ssl/connection_impl.h

@@ -6,6 +6,8 @@
 #include "common/network/connection_impl.h"
 #include "common/ssl/context_impl.h"
 
+#include "openssl/ssl.h"
+
 namespace Envoy {
 namespace Ssl {
 
@@ -29,6 +31,7 @@ class ConnectionImpl : public Network::ConnectionImpl, public Connection {
   std::string sha256PeerCertificateDigest() override;
   std::string subjectPeerCertificate() override;
   std::string uriSanPeerCertificate() override;
+  SSL* rawSslForTest() override { return ssl_.get(); }
 
 private:
   PostIoAction doHandshake();

source/common/ssl/context_impl.cc

@@ -44,11 +44,6 @@ ContextImpl::ContextImpl(ContextManagerImpl& parent, Stats::Scope& scope, Contex
       throw EnvoyException(
           fmt::format("Failed to load verify locations file {}", config.caCertFile()));
     }
-
-    // This will send an acceptable CA list to browsers which will prevent pop ups.
-    rc = SSL_CTX_add_client_CA(ctx_.get(), ca_cert_.get());
-    RELEASE_ASSERT(1 == rc);
-
     verify_mode = SSL_VERIFY_PEER;
   }
 
@@ -351,6 +346,15 @@ bssl::UniquePtr<SSL> ClientContextImpl::newSsl() const {
 ServerContextImpl::ServerContextImpl(ContextManagerImpl& parent, Stats::Scope& scope,
                                      ContextConfig& config, Runtime::Loader& runtime)
     : ContextImpl(parent, scope, config), runtime_(runtime) {
+  if (!config.caCertFile().empty()) {
+    bssl::UniquePtr<STACK_OF(X509_NAME)> list(SSL_load_client_CA_file(config.caCertFile().c_str()));
+    if (nullptr == list) {
+      throw EnvoyException(fmt::format("Failed to load client CA file {}", config.caCertFile()));
+    }
+    SSL_CTX_set_client_CA_list(ctx_.get(), list.release());
+    // SSL_CTX_set_verify() was already set in ContextImpl::ContextImpl().
+  }
+
   parsed_alt_alpn_protocols_ = parseAlpnProtocols(config.altAlpnProtocols());
 
   if (!parsed_alpn_protocols_.empty()) {

test/common/ssl/BUILD

@@ -18,6 +18,7 @@ envoy_cc_test(
         "gen_unittest_certs.sh",
         "//test/common/ssl/test_data:certs",
     ],
+    external_deps = ["ssl"],
     deps = [
         "//source/common/buffer:buffer_lib",
         "//source/common/event:dispatcher_includes",

test/common/ssl/connection_impl_test.cc

@@ -24,6 +24,7 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "openssl/ssl.h"
 
 namespace Envoy {
 using testing::Invoke;
@@ -263,6 +264,80 @@ TEST_P(SslConnectionImplTest, FailedClientAuthHashVerification) {
            GetParam());
 }
 
+TEST_P(SslConnectionImplTest, ClientAuthMultipleCAs) {
+  Stats::IsolatedStoreImpl stats_store;
+  Runtime::MockLoader runtime;
+
+  std::string server_ctx_json = R"EOF(
+  {
+    "cert_chain_file": "{{ test_tmpdir }}/unittestcert.pem",
+    "private_key_file": "{{ test_tmpdir }}/unittestkey.pem",
+    "ca_cert_file": "{{ test_rundir }}/test/common/ssl/test_data/ca_certificates.pem"
+  }
+  )EOF";
+
+  Json::ObjectSharedPtr server_ctx_loader = TestEnvironment::jsonLoadFromString(server_ctx_json);
+  ContextConfigImpl server_ctx_config(*server_ctx_loader);
+  ContextManagerImpl manager(runtime);
+  ServerContextPtr server_ctx(manager.createSslServerContext(stats_store, server_ctx_config));
+
+  Event::DispatcherImpl dispatcher;
+  Network::TcpListenSocket socket(Network::Test::getCanonicalLoopbackAddress(GetParam()), true);
+  Network::MockListenerCallbacks callbacks;
+  Network::MockConnectionHandler connection_handler;
+  Network::ListenerPtr listener =
+      dispatcher.createSslListener(connection_handler, *server_ctx, socket, callbacks, stats_store,
+                                   Network::ListenerOptions::listenerOptionsWithBindToPort());
+
+  std::string client_ctx_json = R"EOF(
+  {
+    "cert_chain_file": "{{ test_rundir }}/test/common/ssl/test_data/no_san_cert.pem",
+    "private_key_file": "{{ test_rundir }}/test/common/ssl/test_data/no_san_key.pem"
+  }
+  )EOF";
+
+  Json::ObjectSharedPtr client_ctx_loader = TestEnvironment::jsonLoadFromString(client_ctx_json);
+  ContextConfigImpl client_ctx_config(*client_ctx_loader);
+  ClientContextPtr client_ctx(manager.createSslClientContext(stats_store, client_ctx_config));
+  Network::ClientConnectionPtr client_connection =
+      dispatcher.createSslClientConnection(*client_ctx, socket.localAddress());
+
+  Ssl::Connection* ssl_connection = client_connection->ssl();
+  ASSERT(ssl_connection != nullptr);
+  SSL* ssl = ssl_connection->rawSslForTest();
+  ASSERT(ssl != nullptr);
+  SSL_set_cert_cb(ssl,
+                  [](SSL* ssl, void*) -> int {
+                    STACK_OF(X509_NAME)* list = SSL_get_client_CA_list(ssl);
+                    EXPECT_NE(nullptr, list);
+                    EXPECT_EQ(2U, sk_X509_NAME_num(list));
+                    return 1;
+                  },
+                  nullptr);
+
+  client_connection->connect();
+
+  Network::ConnectionPtr server_connection;
+  Network::MockConnectionCallbacks server_connection_callbacks;
+  EXPECT_CALL(callbacks, onNewConnection_(_))
+      .WillOnce(Invoke([&](Network::ConnectionPtr& conn) -> void {
+        server_connection = std::move(conn);
+        server_connection->addConnectionCallbacks(server_connection_callbacks);
+      }));
+
+  EXPECT_CALL(server_connection_callbacks, onEvent(Network::ConnectionEvent::Connected))
+      .WillOnce(Invoke([&](uint32_t) -> void {
+        server_connection->close(Network::ConnectionCloseType::NoFlush);
+        client_connection->close(Network::ConnectionCloseType::NoFlush);
+        dispatcher.exit();
+      }));
+  EXPECT_CALL(server_connection_callbacks, onEvent(Network::ConnectionEvent::LocalClose));
+
+  dispatcher.run(Event::Dispatcher::RunType::Block);
+
+  EXPECT_EQ(1UL, stats_store.counter("ssl.handshake").value());
+}
+
 TEST_P(SslConnectionImplTest, SslError) {
   Stats::IsolatedStoreImpl stats_store;
   Runtime::MockLoader runtime;

test/common/ssl/test_data/README.md

@@ -1,8 +1,11 @@
 # What are the identities, certificates and keys
-There are 5 identities:
+There are 6 identities:
 - **CA**: Certificate Authority for **No SAN**, **SAN With URI** and **SAN With
   DNS**. It has the self-signed certificate *ca_cert.pem*. *ca_key.pem* is its
   private key.
+-- **Fake CA**: Fake Certificate Authority used to validate verification logic.
+-  It has the self-signed certificate *fake_ca_cert.pem"*. *fake_ca_key.pem" is
+-  its private key.
 - **No SAN**: It has the certificate *no_san_cert.pem*, signed by the **CA**.
   The certificate does not have SAN field. *no_san_key.pem* is its private key.
 - **SAN With URI**: It has the certificate *san_uri_cert.pem*, which is signed

test/common/ssl/test_data/ca_certificates.pem

@@ -0,0 +1,36 @@
+-----BEGIN CERTIFICATE-----
+MIICzTCCAjagAwIBAgIJAPAEjHA3MX2BMA0GCSqGSIb3DQEBCwUAMHYxCzAJBgNV
+BAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1TYW4gRnJhbmNp
+c2NvMQ0wCwYDVQQKEwRMeWZ0MRkwFwYDVQQLExBMeWZ0IEVuZ2luZWVyaW5nMRAw
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+djELMAkGA1UEBhMCVVMxEzARBgNVBAgTCkNhbGlmb3JuaWExFjAUBgNVBAcTDVNh
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+IPLTWXLVyh49yh5FCs6nt2/LrIuZX/K2cZQx+VuLCcg5sTllAgMBAAGjYzBhMA8G
+A1UdEwEB/wQFMAMBAf8wDgYDVR0PAQH/BAQDAgEGMB0GA1UdDgQWBBRRsE37S/H/
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+Sj+kenx0v3GMrPZMAsELiPG5PcSk8l5prDgU7VkzNvoCtypCsB7RQRyvZs52Qih3
+Ug==
+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----
+MIICzTCCAjagAwIBAgIJAOrzsOodDleaMA0GCSqGSIb3DQEBCwUAMHYxCzAJBgNV
+BAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1TYW4gRnJhbmNp
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+gCp7/9TRW0bRGL6Qp6od/u62L8dprdHXxnck/+sZMupam9YrAgMBAAGjYzBhMA8G
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+kxxIKHoMrSuWQcp9eTAfBgNVHSMEGDAWgBQ7eKRRTxaEkxxIKHoMrSuWQcp9eTAN
+BgkqhkiG9w0BAQsFAAOBgQCN00/2k9k8HNeJ8eYuFH10jnc+td7+OaYWpRSEKCS7
+ux3KAu0UFt90mojEMClt4Y6uP4oXTWbRzMzAgQHldHU8Gkj8tYnv7mToX7Bh/xdc
+19epzjCmo/4Q6+16GZZvltiFjkkHSZEVI5ggljy1QdMIPRegsKKmX9mjZSCSSXD6
+SA==
+-----END CERTIFICATE-----

test/common/ssl/test_data/certs.sh

@@ -4,14 +4,23 @@ set -e
 
 # Uncomment the following lines if you want to regenerate the private keys.
 # openssl genrsa -out ca_key.pem 1024
+# openssl genrsa -out fake_ca_key.pem 1024
 # openssl genrsa -out no_san_key.pem 1024
 # openssl genrsa -out san_dns_key.pem 1024
 # openssl genrsa -out san_uri_key.pem 1024
+# openssl genrsa -out selfsigned_key.pem 1024
 
 # Generate ca_cert.pem.
 openssl req -new -key ca_key.pem -out ca_cert.csr -config ca_cert.cfg -batch -sha256
 openssl x509 -req -days 3650 -in ca_cert.csr -signkey ca_key.pem -out ca_cert.pem -extensions v3_ca -extfile ca_cert.cfg
 
+# Generate fake_ca_cert.pem.
+openssl req -new -key fake_ca_key.pem -out fake_ca_cert.csr -config fake_ca_cert.cfg -batch -sha256
+openssl x509 -req -days 3650 -in fake_ca_cert.csr -signkey fake_ca_key.pem -out fake_ca_cert.pem -extensions v3_ca -extfile fake_ca_cert.cfg
+
+# Concatenate Fake CA (fake_ca_cert.pem) and Test CA (ca_cert.pem) to create CA file with multiple entries.
+cat fake_ca_cert.pem ca_cert.pem > ca_certificates.pem
+
 # Generate no_san_cert.pem.
 openssl req -new -key no_san_key.pem -out no_san_cert.csr -config no_san_cert.cfg -batch -sha256
 openssl x509 -req -days 730 -in no_san_cert.csr -sha256 -CA ca_cert.pem -CAkey ca_key.pem -CAcreateserial -out no_san_cert.pem -extensions v3_ca -extfile no_san_cert.cfg

test/common/ssl/test_data/fake_ca_cert.cfg

@@ -0,0 +1,29 @@
+[req]
+distinguished_name = req_distinguished_name
+req_extensions = v3_req
+
+[req_distinguished_name]
+countryName = US
+countryName_default = US
+stateOrProvinceName = California
+stateOrProvinceName_default = California
+localityName = San Francisco
+localityName_default = San Francisco
+organizationName = Lyft
+organizationName_default = Lyft
+organizationalUnitName = Lyft Engineering
+organizationalUnitName_default = Lyft Engineering
+commonName = Fake CA
+commonName_default = Fake CA
+commonName_max  = 64
+
+[v3_req]
+basicConstraints = CA:TRUE
+keyUsage = critical, cRLSign, keyCertSign
+subjectKeyIdentifier = hash
+
+[v3_ca]
+basicConstraints = critical, CA:TRUE
+keyUsage = critical, cRLSign, keyCertSign
+subjectKeyIdentifier = hash
+authorityKeyIdentifier = keyid:always

test/common/ssl/test_data/fake_ca_cert.pem

@@ -0,0 +1,18 @@
+-----BEGIN CERTIFICATE-----
+MIICzTCCAjagAwIBAgIJAPAEjHA3MX2BMA0GCSqGSIb3DQEBCwUAMHYxCzAJBgNV
+BAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1TYW4gRnJhbmNp
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+Ug==
+-----END CERTIFICATE-----

test/common/ssl/test_data/fake_ca_key.pem

@@ -0,0 +1,15 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIICXAIBAAKBgQCv/PUe49JMIRoezQwIroZVZjdR4e97BkcwwYDjf2X5iUoJL2SM
+EOPobtMGesIzdGptYiCsqfDtTpJirq3HwkUDNkBoiFCO7+60mtBs6hDaBLEBl1ZP
+P8ocA/GLPSDy01ly1coePcoeRQrOp7dvy6yLmV/ytnGUMflbiwnIObE5ZQIDAQAB
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+f2owZgkfS+pA3OPILNNBF7LtClqmc3frPMXcO/NILlgNrkRLYy4MjWUOrMQ86VP0
+ZM1VmiuK9ouEx8X7RKMCQB4NOyFDGIP0IKNCrLKZcMG2c3utcd23CbwH70BgH9kt
+2SOc0pEXdbuVLtgofLS/dULXj7gyDekYejZzqYeY/1E=
+-----END RSA PRIVATE KEY-----

test/mocks/ssl/BUILD

@@ -12,6 +12,7 @@ envoy_cc_mock(
     name = "ssl_mocks",
     srcs = ["mocks.cc"],
     hdrs = ["mocks.h"],
+    external_deps = ["ssl"],
     deps = [
         "//include/envoy/ssl:connection_interface",
         "//include/envoy/ssl:context_config_interface",

test/mocks/ssl/mocks.h

@@ -10,6 +10,7 @@
 #include "envoy/stats/stats.h"
 
 #include "gmock/gmock.h"
+#include "openssl/ssl.h"
 
 namespace Envoy {
 namespace Ssl {
@@ -43,6 +44,7 @@ class MockConnection : public Connection {
   MOCK_METHOD0(sha256PeerCertificateDigest, std::string());
   MOCK_METHOD0(subjectPeerCertificate, std::string());
   MOCK_METHOD0(uriSanPeerCertificate, std::string());
+  MOCK_METHOD0(rawSslForTest, SSL*());
 };
 
 class MockClientContext : public ClientContext {