Merge pull request #6726 from julek-wolfssl/dropped-ccs

Server should not ignore plaintext packets as long as it has stuff to rtx

Author: JacobBarthelmeh

src/internal.c

@@ -9199,13 +9199,21 @@ int VerifyForDtlsMsgPoolSend(WOLFSSL* ssl, byte type, word32 fragOffset)
      * to be used for triggering retransmission of whole DtlsMsgPool.
      * change cipher suite type is not verified here
      */
-    return ((fragOffset == 0) &&
-           (((ssl->options.side == WOLFSSL_SERVER_END) &&
-             ((type == client_hello) ||
-             ((ssl->options.verifyPeer) && (type == certificate)) ||
-             ((!ssl->options.verifyPeer) && (type == client_key_exchange)))) ||
-            ((ssl->options.side == WOLFSSL_CLIENT_END) &&
-             (type == hello_request || type == server_hello))));
+    if (fragOffset == 0) {
+        if (ssl->options.side == WOLFSSL_SERVER_END) {
+            if (type == client_hello)
+                return 1;
+            else if (ssl->options.verifyPeer && type == certificate)
+                return 1;
+            else if (!ssl->options.verifyPeer && type == client_key_exchange)
+                return 1;
+        }
+        else {
+            if (type == hello_request || type == server_hello)
+                return 1;
+        }
+    }
+    return 0;
 }
 
 
@@ -20003,9 +20011,10 @@ static int HandleDTLSDecryptFailed(WOLFSSL* ssl)
 
 static int DtlsShouldDrop(WOLFSSL* ssl, int retcode)
 {
-    if (ssl->options.handShakeDone && !IsEncryptionOn(ssl, 0)) {
+    if (ssl->options.handShakeDone && !IsEncryptionOn(ssl, 0) &&
+            !ssl->options.dtlsHsRetain) {
         WOLFSSL_MSG("Silently dropping plaintext DTLS message "
-                    "on established connection.");
+                    "on established connection when we have nothing to send.");
         return 1;
     }
 

tests/api.c

@@ -64936,6 +64936,73 @@ static int test_dtls_client_hello_timeout(void)
     return EXPECT_RESULT();
 }
 
+/* DTLS test when dropping the changed cipher spec message */
+static int test_dtls_dropped_ccs(void)
+{
+    EXPECT_DECLS;
+#if defined(HAVE_MANUAL_MEMIO_TESTS_DEPENDENCIES) && defined(WOLFSSL_DTLS)
+    WOLFSSL_CTX *ctx_c = NULL;
+    WOLFSSL_CTX *ctx_s = NULL;
+    WOLFSSL *ssl_c = NULL;
+    WOLFSSL *ssl_s = NULL;
+    struct test_memio_ctx test_ctx;
+    DtlsRecordLayerHeader* dtlsRH;
+    size_t len;
+    byte data[1];
+
+
+    XMEMSET(&test_ctx, 0, sizeof(test_ctx));
+
+    ExpectIntEQ(test_memio_setup(&test_ctx, &ctx_c, &ctx_s, &ssl_c, &ssl_s,
+        wolfDTLSv1_2_client_method, wolfDTLSv1_2_server_method), 0);
+
+    /* CH1 */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_c), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
+    /* HVR */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_s), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
+    /* CH2 */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_c), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
+    /* Server first flight */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_s), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
+    /* Client flight */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_c), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
+    /* Server ccs + finished */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_s), 1);
+
+    /* Drop the ccs */
+    dtlsRH = (DtlsRecordLayerHeader*)test_ctx.c_buff;
+    len = (size_t)((dtlsRH->length[0] << 8) | dtlsRH->length[1]);
+    ExpectIntEQ(len, 1);
+    ExpectIntEQ(dtlsRH->type, change_cipher_spec);
+    if (EXPECT_SUCCESS()) {
+        XMEMMOVE(test_ctx.c_buff, test_ctx.c_buff +
+                sizeof(DtlsRecordLayerHeader) + len, test_ctx.c_len -
+               (sizeof(DtlsRecordLayerHeader) + len));
+    }
+    test_ctx.c_len -= sizeof(DtlsRecordLayerHeader) + len;
+
+    /* Client rtx flight */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_c), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_c, -1), WOLFSSL_ERROR_WANT_READ);
+    ExpectIntEQ(wolfSSL_dtls_got_timeout(ssl_c), WOLFSSL_SUCCESS);
+    /* Server ccs + finished rtx */
+    ExpectIntEQ(wolfSSL_read(ssl_s, data, sizeof(data)), -1);
+    ExpectIntEQ(wolfSSL_get_error(ssl_s, -1), WOLFSSL_ERROR_WANT_READ);
+    /* Client processes finished */
+    ExpectIntEQ(wolfSSL_negotiate(ssl_c), 1);
+
+    wolfSSL_free(ssl_c);
+    wolfSSL_free(ssl_s);
+    wolfSSL_CTX_free(ctx_c);
+    wolfSSL_CTX_free(ctx_s);
+#endif
+    return EXPECT_RESULT();
+}
 /**
  * Make sure we don't send RSA Signature Hash Algorithms in the
  * CertificateRequest when we don't have any such ciphers set.
@@ -66286,6 +66353,7 @@ TEST_CASE testCases[] = {
     TEST_DECL(test_dtls_downgrade_scr),
     TEST_DECL(test_dtls_client_hello_timeout_downgrade),
     TEST_DECL(test_dtls_client_hello_timeout),
+    TEST_DECL(test_dtls_dropped_ccs),
     TEST_DECL(test_certreq_sighash_algos),
     /* This test needs to stay at the end to clean up any caches allocated. */
     TEST_DECL(test_wolfSSL_Cleanup)