Use the TLSv1.3 record header as AAD

As of TLSv1.3 draft-25 the record header data must be used as AAD
Reviewed-by: NBen Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/5604)

engines/e_ossltest.c

@@ -637,7 +637,7 @@ int ossltest_aes128_gcm_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
     EVP_CIPHER_meth_get_do_cipher(EVP_aes_128_gcm())(ctx, out, in, inl);
 
     /* Throw it all away and just use the plaintext as the output */
-    if (tmpbuf != NULL)
+    if (tmpbuf != NULL && out != NULL)
         memcpy(out, tmpbuf, inl);
     OPENSSL_free(tmpbuf);
 

ssl/record/rec_layer_s3.c

@@ -825,7 +825,6 @@ int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
         thispkt = &pkt[j];
         thiswr = &wr[j];
 
-        SSL3_RECORD_set_type(thiswr, type);
         /*
          * In TLSv1.3, once encrypting, we always use application data for the
          * record type
@@ -834,6 +833,8 @@ int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
             rectype = SSL3_RT_APPLICATION_DATA;
         else
             rectype = type;
+        SSL3_RECORD_set_type(thiswr, rectype);
+
         /*
          * Some servers hang if initial client hello is larger than 256 bytes
          * and record version number > TLS 1.0
@@ -843,6 +844,7 @@ int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
                 && TLS1_get_version(s) > TLS1_VERSION
                 && s->hello_retry_request == SSL_HRR_NONE)
             version = TLS1_VERSION;
+        SSL3_RECORD_set_rec_version(thiswr, version);
 
         maxcomplen = pipelens[j];
         if (s->compress != NULL)

ssl/record/record_locl.h

@@ -80,6 +80,7 @@ int ssl3_release_write_buffer(SSL *s);
 
 #define SSL3_RECORD_get_type(r)                 ((r)->type)
 #define SSL3_RECORD_set_type(r, t)              ((r)->type = (t))
+#define SSL3_RECORD_set_rec_version(r, v)       ((r)->rec_version = (v))
 #define SSL3_RECORD_get_length(r)               ((r)->length)
 #define SSL3_RECORD_set_length(r, l)            ((r)->length = (l))
 #define SSL3_RECORD_add_length(r, l)            ((r)->length += (l))

ssl/record/ssl3_record.c

@@ -270,7 +270,8 @@ int ssl3_get_record(SSL *s)
                 thisrr->rec_version = version;
 
                 /*
-                 * Lets check version. In TLSv1.3 we ignore this field. For the
+                 * Lets check version. In TLSv1.3 we only check this field
+                 * when encryption is occurring (see later check). For the
                  * ServerHello after an HRR we haven't actually selected TLSv1.3
                  * yet, but we still treat it as TLSv1.3, so we must check for
                  * that explicitly
@@ -333,14 +334,19 @@ int ssl3_get_record(SSL *s)
                     }
                 }
 
-                if (SSL_IS_TLS13(s)
-                        && s->enc_read_ctx != NULL
-                        && thisrr->type != SSL3_RT_APPLICATION_DATA
-                        && (thisrr->type != SSL3_RT_CHANGE_CIPHER_SPEC
-                            || !SSL_IS_FIRST_HANDSHAKE(s))) {
-                    SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
-                             SSL_F_SSL3_GET_RECORD, SSL_R_BAD_RECORD_TYPE);
-                    return -1;
+                if (SSL_IS_TLS13(s) && s->enc_read_ctx != NULL) {
+                    if (thisrr->type != SSL3_RT_APPLICATION_DATA
+                            && (thisrr->type != SSL3_RT_CHANGE_CIPHER_SPEC
+                                || !SSL_IS_FIRST_HANDSHAKE(s))) {
+                        SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE,
+                                 SSL_F_SSL3_GET_RECORD, SSL_R_BAD_RECORD_TYPE);
+                        return -1;
+                    }
+                    if (thisrr->rec_version != TLS1_2_VERSION) {
+                        SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD,
+                                 SSL_R_WRONG_VERSION_NUMBER);
+                        return -1;
+                    }
                 }
 
                 if (thisrr->length >

ssl/record/ssl3_record_tls13.c

@@ -25,13 +25,14 @@
 int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
 {
     EVP_CIPHER_CTX *ctx;
-    unsigned char iv[EVP_MAX_IV_LENGTH];
-    size_t ivlen, taglen, offset, loop;
+    unsigned char iv[EVP_MAX_IV_LENGTH], recheader[SSL3_RT_HEADER_LENGTH];
+    size_t ivlen, taglen, offset, loop, hdrlen;
     unsigned char *staticiv;
     unsigned char *seq;
     int lenu, lenf;
     SSL3_RECORD *rec = &recs[0];
     uint32_t alg_enc;
+    WPACKET wpkt;
 
     if (n_recs != 1) {
         /* Should not happen */
@@ -143,7 +144,31 @@ int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
     if (EVP_CipherInit_ex(ctx, NULL, NULL, NULL, iv, sending) <= 0
             || (!sending && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG,
                                              taglen,
-                                             rec->data + rec->length) <= 0)
+                                             rec->data + rec->length) <= 0)) {
+        return -1;
+    }
+
+    /* Set up the AAD */
+    if (!WPACKET_init_static_len(&wpkt, recheader, sizeof(recheader), 0)
+            || !WPACKET_put_bytes_u8(&wpkt, rec->type)
+            || !WPACKET_put_bytes_u16(&wpkt, rec->rec_version)
+            || !WPACKET_put_bytes_u16(&wpkt, rec->length + taglen)
+            || !WPACKET_get_total_written(&wpkt, &hdrlen)
+            || hdrlen != SSL3_RT_HEADER_LENGTH
+            || !WPACKET_finish(&wpkt)) {
+        WPACKET_cleanup(&wpkt);
+        return -1;
+    }
+
+    /*
+     * For CCM we must explicitly set the total plaintext length before we add
+     * any AAD.
+     */
+    if (((alg_enc & SSL_AESCCM) != 0
+                 && EVP_CipherUpdate(ctx, NULL, &lenu, NULL,
+                                     (unsigned int)rec->length) <= 0)
+            || EVP_CipherUpdate(ctx, NULL, &lenu, recheader,
+                                sizeof(recheader)) <= 0
             || EVP_CipherUpdate(ctx, rec->data, &lenu, rec->input,
                                 (unsigned int)rec->length) <= 0
             || EVP_CipherFinal_ex(ctx, rec->data + lenu, &lenf) <= 0

test/recipes/70-test_sslrecords.t

@@ -149,11 +149,11 @@ ok(TLSProxy::Message->fail(), "Changed record version in TLS1.2");
 SKIP: {
     skip "TLSv1.3 disabled", 6 if disabled("tls1_3");
 
-    #Test 13: Sending a different record version in TLS1.3 should succeed
+    #Test 13: Sending a different record version in TLS1.3 should fail
     $proxy->clear();
     $proxy->filter(\&change_version);
     $proxy->start();
-    ok(TLSProxy::Message->success(), "Changed record version in TLS1.3");
+    ok(TLSProxy::Message->fail(), "Changed record version in TLS1.3");
 
     #Test 14: Sending an unrecognised record type in TLS1.3 should fail
     $proxy->clear();
@@ -464,7 +464,7 @@ sub change_version
     my $proxy = shift;
 
     # We'll change a version after the initial version neg has taken place
-    if ($proxy->flight != 2) {
+    if ($proxy->flight != 1) {
         return;
     }
 

test/recordlentest.c

@@ -157,11 +157,7 @@ static int test_record_overflow(int idx)
         overf_expected = 0;
     }
 
-    if (idx == TEST_ENCRYPTED_OVERFLOW_TLS1_3_OK
-            || idx == TEST_ENCRYPTED_OVERFLOW_TLS1_3_NOT_OK)
-        recversion = TLS1_VERSION;
-    else
-        recversion = TLS1_2_VERSION;
+    recversion = TLS1_2_VERSION;
 
     if (!TEST_true(write_record(serverbio, len, SSL3_RT_APPLICATION_DATA,
                                 recversion)))

test/tls13encryptiontest.c

@@ -92,7 +92,7 @@ static RECORD_DATA refdata[] = {
             "83dd29f64508b2ec3e635a2134fc0e1a39d3ecb51dcddfcf8382c88ffe2a7378"
             "42ad1de7fe505b6c4d1673870f6fc2a0f2f7972acaee368a1599d64ba18798f1"
             "0333f9779bd5b05f9b084d03dab2f3d80c2eb74ec70c9866ea31c18b491cd597"
-            "aae3e941205fcc38a3a10ce8c0269f02ccc9c51278e25f1a0f0731a9"
+            "aae3e941205fcc38a3a10ce8f2e230d97e3406b77ee53d84d89ca548"
         },
         "d2dd45f87ad87801a85ac38187f9023b",
         "f0a14f808692cef87a3daf70",
@@ -106,7 +106,7 @@ static RECORD_DATA refdata[] = {
         },
         {
             "fa15e92daa21cd05d8f9c3152a61748d9aaf049da559718e583f95aacecad657"
-            "b52a6562da09a5819e864d86ac2989360a1eb22795","",""
+            "b52a6562da66864fd14969acc30dc04a78c38283c5","",""
         },
         "40e1201d75d419627f04c88530a15c9d",
         "a0f073f3b35e18f96969696b",
@@ -128,7 +128,7 @@ static RECORD_DATA refdata[] = {
             "836905229eac811c4ef8b2faa89867e9ffc586f7f03c216591aa5e620eac3c62"
             "dfe60f846036bd7ecc4464b584af184e9644e94ee1d7834dba408a51cbe42480"
             "04796ed9c558e0f5f96115a6f6ba487e17d16a2e20a3d3a650a9a070fb53d9da"
-            "82864b5621d77650bd0c7947e9889917b53d0515627c72b0ded521","",""
+            "82864b5621d77650bd0c7972f592aa8546de09b8e46921fab4d876","",""
         },
         "3381f6b3f94500f16226de440193e858",
         "4f1d73cc1d465eb30021c41f",
@@ -142,8 +142,8 @@ static RECORD_DATA refdata[] = {
         },
         {
             "e306178ad97f74bb64f35eaf3c39846b83aef8472cbc9046749b81a949dfb12c"
-            "fbc65cbabd20ade92c1f944605892ceeb12fdee8a927bce77c83036ac5a794a8"
-            "f54a69","",""
+            "fbc65cbabd20ade92c1f944605892ceeb12fde5781d40e2ca080fc921b750b8c"
+            "21bd8d","",""
         },
         "eb23a804904b80ba4fe8399e09b1ce42",
         "efa8c50c06b9c9b8c483e174",
@@ -157,8 +157,8 @@ static RECORD_DATA refdata[] = {
         },
         {
             "467d99a807dbf778e6ffd8be52456c70665f890811ef2f3c495d5bbe983feeda"
-            "b0c251dde596bc7e2b135909ec9f9166fb0152e8c16a84e4b1039256467f9538"
-            "be4463","",""
+            "b0c251dde596bc7e2b135909ec9f9166fb01526c70c7e42b6df52d63b0000222"
+            "cb2047","",""
         },
         "3381f6b3f94500f16226de440193e858",
         "4f1d73cc1d465eb30021c41f",
@@ -170,7 +170,7 @@ static RECORD_DATA refdata[] = {
             "010015","",""
         },
         {
-            "6bdf60847ba6fb650da36e872adc684a4af2e8","",""
+            "6bdf609107610cff95d70387a67b89e2494f0d","",""
         },
         "eb23a804904b80ba4fe8399e09b1ce42",
         "efa8c50c06b9c9b8c483e174",
@@ -182,7 +182,7 @@ static RECORD_DATA refdata[] = {
             "010015","",""
         },
         {
-            "621b7cc1962cd8a70109fee68a52efedf87d2e","",""
+            "621b7c60d32528b149b36a78c8891a8d2f65ad","",""
         },
         "3381f6b3f94500f16226de440193e858",
         "4f1d73cc1d465eb30021c41f",
@@ -306,7 +306,13 @@ static int test_tls13_encryption(void)
     int ret = 0;
     size_t ivlen, ctr;
 
+    /*
+     * Encrypted TLSv1.3 records always have an outer content type of
+     * application data, and a record version of TLSv1.2.
+     */
     rec.data = NULL;
+    rec.type = SSL3_RT_APPLICATION_DATA;
+    rec.rec_version = TLS1_2_VERSION;
 
     ctx = SSL_CTX_new(TLS_method());
     if (!TEST_ptr(ctx)) {