Bug 1418943 - Properly handle absent cookie on second ClientHello, r=ekr

4 files changed, 24 insertions, 1 deletions

diff --git a/gtests/ssl_gtest/ssl_hrr_unittest.cc b/gtests/ssl_gtest/ssl_hrr_unittest.cc
index 844e08c48..2251584c1 100644
--- a/gtests/ssl_gtest/ssl_hrr_unittest.cc
+++ b/gtests/ssl_gtest/ssl_hrr_unittest.cc
@@ -595,6 +595,20 @@ TEST_P(TlsConnectTls13, RetryStateless) {
   SendReceive();
 }
 
+TEST_P(TlsConnectTls13, RetryStatefulDropCookie) {
+  ConfigureSelfEncrypt();
+  EnsureTlsSetup();
+
+  TriggerHelloRetryRequest(client_, server_);
+  client_->SetPacketFilter(
+      std::make_shared<TlsExtensionDropper>(ssl_tls13_cookie_xtn));
+
+  ExpectAlert(server_, kTlsAlertMissingExtension);
+  Handshake();
+  client_->CheckErrorCode(SSL_ERROR_MISSING_EXTENSION_ALERT);
+  server_->CheckErrorCode(SSL_ERROR_MISSING_COOKIE_EXTENSION);
+}
+
 // Stream only because DTLS drops bad packets.
 TEST_F(TlsConnectStreamTls13, RetryStatelessDamageFirstClientHello) {
   ConfigureSelfEncrypt();
diff --git a/lib/ssl/SSLerrs.h b/lib/ssl/SSLerrs.h
index e93025aa7..160204201 100644
--- a/lib/ssl/SSLerrs.h
+++ b/lib/ssl/SSLerrs.h
@@ -528,3 +528,6 @@ ER3(SSL_ERROR_APP_CALLBACK_ERROR, (SSL_ERROR_BASE + 166),
 
 ER3(SSL_ERROR_NO_TIMERS_ERROR, (SSL_ERROR_BASE + 167),
     "No timers are currently running.")
+
+ER3(SSL_ERROR_MISSING_COOKIE_EXTENSION, (SSL_ERROR_BASE + 168),
+    "A second ClientHello was received without a cookie extension.")
diff --git a/lib/ssl/sslerr.h b/lib/ssl/sslerr.h
index 275905a42..00e580ab3 100644
--- a/lib/ssl/sslerr.h
+++ b/lib/ssl/sslerr.h
@@ -255,6 +255,7 @@ typedef enum {
     SSL_ERROR_APPLICATION_ABORT = (SSL_ERROR_BASE + 165),
     SSL_ERROR_APP_CALLBACK_ERROR = (SSL_ERROR_BASE + 166),
     SSL_ERROR_NO_TIMERS_FOUND = (SSL_ERROR_BASE + 167),
+    SSL_ERROR_MISSING_COOKIE_EXTENSION = (SSL_ERROR_BASE + 168),
 
     SSL_ERROR_END_OF_LIST   /* let the c compiler determine the value of this. */
 } SSLErrorCodes;
diff --git a/lib/ssl/tls13con.c b/lib/ssl/tls13con.c
index 7a7134416..18a330eba 100644
--- a/lib/ssl/tls13con.c
+++ b/lib/ssl/tls13con.c
@@ -1375,7 +1375,12 @@ tls13_HandleClientHelloPart2(sslSocket *ss,
             ssl_ReleaseSpecWriteLock(ss);
         }
 
-        PORT_Assert(ss->xtnData.cookie.len);
+        if (!ssl3_ExtensionNegotiated(ss, ssl_tls13_cookie_xtn) ||
+            !ss->xtnData.cookie.len) {
+            FATAL_ERROR(ss, SSL_ERROR_MISSING_COOKIE_EXTENSION,
+                        missing_extension);
+            goto loser;
+        }
         PRINT_BUF(50, (ss, "Client sent cookie",
                        ss->xtnData.cookie.data, ss->xtnData.cookie.len));