Use the TLSv1.3 record header as AAD

[openssl.git] / ssl / record / ssl3_record_tls13.c

diff --git a/ssl/record/ssl3_record_tls13.c b/ssl/record/ssl3_record_tls13.c
index 0c3fc6bf16073f5fbec9f27275d026522cf9901f..21073b637de6c5447520a9a69141f2cc5d97862a 100644 (file)
--- a/ssl/record/ssl3_record_tls13.c
+++ b/ssl/record/ssl3_record_tls13.c
@@ -12,7 +12,8 @@
 #include "internal/cryptlib.h"
 
 /*-
- * tls13_enc encrypts/decrypts |n_recs| in |recs|.
+ * tls13_enc encrypts/decrypts |n_recs| in |recs|. Will call SSLfatal() for
+ * internal errors, but not otherwise.
  *
  * Returns:
  *    0: (in non-constant time) if the record is publically invalid (i.e. too
@@ -24,17 +25,20 @@
 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 */
         /* TODO(TLS1.3): Support pipelining */
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                 ERR_R_INTERNAL_ERROR);
         return -1;
     }
 
@@ -58,17 +62,27 @@ int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
 
     if (s->early_data_state == SSL_EARLY_DATA_WRITING
             || s->early_data_state == SSL_EARLY_DATA_WRITE_RETRY) {
-        if (s->session != NULL && s->session->ext.max_early_data > 0)
+        if (s->session != NULL && s->session->ext.max_early_data > 0) {
             alg_enc = s->session->cipher->algorithm_enc;
-        else
+        } else {
+            if (!ossl_assert(s->psksession != NULL
+                             && s->psksession->ext.max_early_data > 0)) {
+                SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                         ERR_R_INTERNAL_ERROR);
+                return -1;
+            }
             alg_enc = s->psksession->cipher->algorithm_enc;
+        }
     } else {
         /*
          * To get here we must have selected a ciphersuite - otherwise ctx would
          * be NULL
          */
-        if (!ossl_assert(s->s3->tmp.new_cipher != NULL))
+        if (!ossl_assert(s->s3->tmp.new_cipher != NULL)) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                     ERR_R_INTERNAL_ERROR);
             return -1;
+        }
         alg_enc = s->s3->tmp.new_cipher->algorithm_enc;
     }
 
@@ -78,13 +92,18 @@ int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
          else
             taglen = EVP_CCM_TLS_TAG_LEN;
          if (sending && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, taglen,
-                                         NULL) <= 0)
+                                         NULL) <= 0) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                     ERR_R_INTERNAL_ERROR);
             return -1;
+        }
     } else if (alg_enc & SSL_AESGCM) {
         taglen = EVP_GCM_TLS_TAG_LEN;
     } else if (alg_enc & SSL_CHACHA20) {
         taglen = EVP_CHACHAPOLY_TLS_TAG_LEN;
     } else {
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                 ERR_R_INTERNAL_ERROR);
         return -1;
     }
 
@@ -101,6 +120,8 @@ int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
     /* Set up IV */
     if (ivlen < SEQ_NUM_SIZE) {
         /* Should not happen */
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                 ERR_R_INTERNAL_ERROR);
         return -1;
     }
     offset = ivlen - SEQ_NUM_SIZE;
@@ -123,7 +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
@@ -133,8 +178,11 @@ int tls13_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending)
     if (sending) {
         /* Add the tag */
         if (EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, taglen,
-                                rec->data + rec->length) <= 0)
+                                rec->data + rec->length) <= 0) {
+            SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS13_ENC,
+                     ERR_R_INTERNAL_ERROR);
             return -1;
+        }
         rec->length += taglen;
     }