Implement OCSP stapling in TLS 1.3.

Change-Id: Iad572f44448141c5e2be49bf25b42719c625a97a
Reviewed-on: https://boringssl-review.googlesource.com/8812
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

ssl/t1_lib.c

@@ -1184,6 +1184,12 @@ static int ext_ocsp_parse_serverhello(SSL *ssl, uint8_t *out_alert,
     return 1;
   }
 
+  /* OCSP stapling is forbidden on a non-certificate cipher. */
+  if (!ssl_cipher_uses_certificate_auth(ssl->s3->tmp.new_cipher)) {
+    return 0;
+  }
+
+  if (ssl3_protocol_version(ssl) < TLS1_3_VERSION) {
     if (CBS_len(contents) != 0) {
       return 0;
     }
@@ -1192,6 +1198,25 @@ static int ext_ocsp_parse_serverhello(SSL *ssl, uint8_t *out_alert,
     return 1;
   }
 
+  uint8_t status_type;
+  CBS ocsp_response;
+  if (!CBS_get_u8(contents, &status_type) ||
+      status_type != TLSEXT_STATUSTYPE_ocsp ||
+      !CBS_get_u24_length_prefixed(contents, &ocsp_response) ||
+      CBS_len(&ocsp_response) == 0 ||
+      CBS_len(contents) != 0) {
+    return 0;
+  }
+
+  if (!CBS_stow(&ocsp_response, &ssl->session->ocsp_response,
+                &ssl->session->ocsp_response_length)) {
+    *out_alert = SSL_AD_INTERNAL_ERROR;
+    return 0;
+  }
+
+  return 1;
+}
+
 static int ext_ocsp_parse_clienthello(SSL *ssl, uint8_t *out_alert,
                                       CBS *contents) {
   if (contents == NULL) {
@@ -1211,14 +1236,15 @@ static int ext_ocsp_parse_clienthello(SSL *ssl, uint8_t *out_alert,
 }
 
 static int ext_ocsp_add_serverhello(SSL *ssl, CBB *out) {
-  if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
+  if (!ssl->s3->tmp.ocsp_stapling_requested ||
+      ssl->ctx->ocsp_response_length == 0 ||
+      !ssl_cipher_uses_certificate_auth(ssl->s3->tmp.new_cipher)) {
     return 1;
   }
 
+  if (ssl3_protocol_version(ssl) < TLS1_3_VERSION) {
     /* The extension shouldn't be sent when resuming sessions. */
-  if (ssl->hit ||
+    if (ssl->hit) {
-      !ssl->s3->tmp.ocsp_stapling_requested ||
-      ssl->ctx->ocsp_response_length == 0) {
       return 1;
     }
 
@@ -1228,6 +1254,16 @@ static int ext_ocsp_add_serverhello(SSL *ssl, CBB *out) {
            CBB_add_u16(out, 0 /* length */);
   }
 
+  CBB body, ocsp_response;
+  return CBB_add_u16(out, TLSEXT_TYPE_status_request) &&
+         CBB_add_u16_length_prefixed(out, &body) &&
+         CBB_add_u8(&body, TLSEXT_STATUSTYPE_ocsp) &&
+         CBB_add_u24_length_prefixed(&body, &ocsp_response) &&
+         CBB_add_bytes(&ocsp_response, ssl->ctx->ocsp_response,
+                       ssl->ctx->ocsp_response_length) &&
+         CBB_flush(out);
+}
+
 
 /* Next protocol negotiation.
  *

ssl/test/runner/runner.go

@@ -507,7 +507,7 @@ func doExchange(test *testCase, config *Config, conn net.Conn, isResume bool) er
 	}
 
 	if test.expectedOCSPResponse != nil && !bytes.Equal(test.expectedOCSPResponse, tlsConn.OCSPResponse()) {
-		return fmt.Errorf("OCSP Response mismatch")
+		return fmt.Errorf("OCSP Response mismatch: got %x, wanted %x", tlsConn.OCSPResponse(), test.expectedOCSPResponse)
 	}
 
 	if test.expectedSCTList != nil && !bytes.Equal(test.expectedSCTList, connState.SCTList) {
@@ -3204,8 +3204,6 @@ func addStateMachineCoverageTests(config stateMachineTestConfig) {
 	})
 
 	// OCSP stapling tests.
-	//
-	// TODO(davidben): Test the TLS 1.3 version of OCSP stapling.
 	tests = append(tests, testCase{
 		testType: clientTest,
 		name:     "OCSPStapling-Client",
@@ -3233,6 +3231,37 @@ func addStateMachineCoverageTests(config stateMachineTestConfig) {
 		},
 		resumeSession: true,
 	})
+	tests = append(tests, testCase{
+		testType: clientTest,
+		name:     "OCSPStapling-Client-TLS13",
+		config: Config{
+			MaxVersion: VersionTLS13,
+		},
+		flags: []string{
+			"-enable-ocsp-stapling",
+			"-expect-ocsp-response",
+			base64.StdEncoding.EncodeToString(testOCSPResponse),
+			"-verify-peer",
+		},
+		// TODO(davidben): Enable this when resumption is implemented
+		// in TLS 1.3.
+		resumeSession: false,
+	})
+	tests = append(tests, testCase{
+		testType: serverTest,
+		name:     "OCSPStapling-Server-TLS13",
+		config: Config{
+			MaxVersion: VersionTLS13,
+		},
+		expectedOCSPResponse: testOCSPResponse,
+		flags: []string{
+			"-ocsp-response",
+			base64.StdEncoding.EncodeToString(testOCSPResponse),
+		},
+		// TODO(davidben): Enable this when resumption is implemented
+		// in TLS 1.3.
+		resumeSession: false,
+	})
 
 	// Certificate verification tests.
 	for _, vers := range tlsVersions {