Enable the ability to use an external PSK for sending early_data
[openssl.git] / ssl / tls13_enc.c
index 2ae45528433857411d8547b9e1b15d6a3f19dd64..1a6ed98d10f9d7609dee59736bf1645fd9b10e08 100644 (file)
 static const unsigned char default_zeros[EVP_MAX_MD_SIZE];
 
 /*
- * Given a |secret|; a |label| of length |labellen|; and a |hash| of the
- * handshake messages, derive a new secret |outlen| bytes long and store it in
- * the location pointed to be |out|. The |hash| value may be NULL. Returns 1 on
- * success  0 on failure.
+ * Given a |secret|; a |label| of length |labellen|; and |data| of length
+ * |datalen| (e.g. typically a hash of the handshake messages), derive a new
+ * secret |outlen| bytes long and store it in the location pointed to be |out|.
+ * The |data| value may be zero length. Returns 1 on success  0 on failure.
  */
 int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
                              const unsigned char *label, size_t labellen,
-                             const unsigned char *hash,
+                             const unsigned char *data, size_t datalen,
                              unsigned char *out, size_t outlen)
 {
-    const unsigned char label_prefix[] = "TLS 1.3, ";
+    const unsigned char label_prefix[] = "tls13 ";
     EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
     int ret;
     size_t hkdflabellen;
@@ -53,7 +53,7 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
             || !WPACKET_memcpy(&pkt, label_prefix, sizeof(label_prefix) - 1)
             || !WPACKET_memcpy(&pkt, label, labellen)
             || !WPACKET_close(&pkt)
-            || !WPACKET_sub_memcpy_u8(&pkt, hash, (hash == NULL) ? 0 : hashlen)
+            || !WPACKET_sub_memcpy_u8(&pkt, data, (data == NULL) ? 0 : datalen)
             || !WPACKET_get_total_written(&pkt, &hkdflabellen)
             || !WPACKET_finish(&pkt)) {
         EVP_PKEY_CTX_free(pctx);
@@ -84,7 +84,7 @@ int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
     static const unsigned char keylabel[] = "key";
 
     return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
-                             NULL, key, keylen);
+                             NULL, 0, key, keylen);
 }
 
 /*
@@ -97,7 +97,7 @@ int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
     static const unsigned char ivlabel[] = "iv";
 
     return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
-                             NULL, iv, ivlen);
+                             NULL, 0, iv, ivlen);
 }
 
 int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
@@ -107,7 +107,7 @@ int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
     static const unsigned char finishedlabel[] = "finished";
 
     return tls13_hkdf_expand(s, md, secret, finishedlabel,
-                             sizeof(finishedlabel) - 1, NULL, fin, finlen);
+                             sizeof(finishedlabel) - 1, NULL, 0, fin, finlen);
 }
 
 /*
@@ -124,7 +124,7 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
     size_t mdlen, prevsecretlen;
     int ret;
     EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_HKDF, NULL);
-    static const char derived_secret_label[] = "derived secret";
+    static const char derived_secret_label[] = "derived";
     unsigned char preextractsec[EVP_MAX_MD_SIZE];
 
     if (pctx == NULL)
@@ -148,6 +148,7 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
                 || EVP_DigestInit_ex(mctx, md, NULL) <= 0
                 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) {
             EVP_MD_CTX_free(mctx);
+            EVP_PKEY_CTX_free(pctx);
             return 0;
         }
         EVP_MD_CTX_free(mctx);
@@ -155,9 +156,11 @@ int tls13_generate_secret(SSL *s, const EVP_MD *md,
         /* Generate the pre-extract secret */
         if (!tls13_hkdf_expand(s, md, prevsecret,
                                (unsigned char *)derived_secret_label,
-                               sizeof(derived_secret_label) - 1, hash,
-                               preextractsec, mdlen))
+                               sizeof(derived_secret_label) - 1, hash, mdlen,
+                               preextractsec, mdlen)) {
+            EVP_PKEY_CTX_free(pctx);
             return 0;
+        }
 
         prevsecret = preextractsec;
         prevsecretlen = mdlen;
@@ -267,7 +270,7 @@ int tls13_setup_key_block(SSL *s)
     return 1;
 }
 
-static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md,
+static int derive_secret_key_and_iv(SSL *s, int sending, const EVP_MD *md,
                                     const EVP_CIPHER *ciph,
                                     const unsigned char *insecret,
                                     const unsigned char *hash,
@@ -279,8 +282,8 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md,
     size_t ivlen, keylen, taglen;
     size_t hashlen = EVP_MD_size(md);
 
-    if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, secret,
-                           hashlen)) {
+    if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, hashlen,
+                           secret, hashlen)) {
         SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR);
         goto err;
     }
@@ -312,7 +315,7 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md,
         goto err;
     }
 
-    if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, send) <= 0
+    if (EVP_CipherInit_ex(ciph_ctx, ciph, NULL, NULL, NULL, sending) <= 0
         || !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_IVLEN, ivlen, NULL)
         || (taglen != 0 && !EVP_CIPHER_CTX_ctrl(ciph_ctx, EVP_CTRL_AEAD_SET_TAG,
                                                 taglen, NULL))
@@ -321,20 +324,6 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md,
         goto err;
     }
 
-#ifdef OPENSSL_SSL_TRACE_CRYPTO
-    if (s->msg_callback) {
-        int wh = send ? TLS1_RT_CRYPTO_WRITE : 0;
-
-        if (ciph->key_len)
-            s->msg_callback(2, s->version, wh | TLS1_RT_CRYPTO_KEY,
-                            key, ciph->key_len, s, s->msg_callback_arg);
-
-        wh |= TLS1_RT_CRYPTO_IV;
-        s->msg_callback(2, s->version, wh, iv, ivlen, s,
-                        s->msg_callback_arg);
-    }
-#endif
-
     return 1;
  err:
     OPENSSL_cleanse(key, sizeof(key));
@@ -343,18 +332,13 @@ static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md,
 
 int tls13_change_cipher_state(SSL *s, int which)
 {
-    static const unsigned char client_early_traffic[] =
-        "client early traffic secret";
-    static const unsigned char client_handshake_traffic[] =
-        "client handshake traffic secret";
-    static const unsigned char client_application_traffic[] =
-        "client application traffic secret";
-    static const unsigned char server_handshake_traffic[] =
-        "server handshake traffic secret";
-    static const unsigned char server_application_traffic[] =
-        "server application traffic secret";
-    static const unsigned char resumption_master_secret[] =
-        "resumption master secret";
+    static const unsigned char client_early_traffic[] = "c e traffic";
+    static const unsigned char client_handshake_traffic[] = "c hs traffic";
+    static const unsigned char client_application_traffic[] = "c ap traffic";
+    static const unsigned char server_handshake_traffic[] = "s hs traffic";
+    static const unsigned char server_application_traffic[] = "s ap traffic";
+    static const unsigned char exporter_master_secret[] = "exp master";
+    static const unsigned char resumption_master_secret[] = "res master";
     unsigned char *iv;
     unsigned char secret[EVP_MAX_MD_SIZE];
     unsigned char hashval[EVP_MAX_MD_SIZE];
@@ -420,6 +404,9 @@ int tls13_change_cipher_state(SSL *s, int which)
                        SSL_R_BAD_HANDSHAKE_LENGTH);
                 goto err;
             }
+
+            if (sslcipher == NULL && s->psksession != NULL)
+                sslcipher = SSL_SESSION_get0_cipher(s->psksession);
             if (sslcipher == NULL) {
                 SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
                 goto err;
@@ -521,11 +508,22 @@ int tls13_change_cipher_state(SSL *s, int which)
         if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
                                resumption_master_secret,
                                sizeof(resumption_master_secret) - 1,
-                               hashval, s->session->master_key, hashlen)) {
+                               hashval, hashlen, s->session->master_key,
+                               hashlen)) {
             SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
             goto err;
         }
         s->session->master_key_length = hashlen;
+
+        /* Now we create the exporter master secret */
+        if (!tls13_hkdf_expand(s, ssl_handshake_md(s), insecret,
+                               exporter_master_secret,
+                               sizeof(exporter_master_secret) - 1,
+                               hash, hashlen, s->exporter_master_secret,
+                               hashlen)) {
+            SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
     }
 
     if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
@@ -557,10 +555,9 @@ int tls13_change_cipher_state(SSL *s, int which)
     return ret;
 }
 
-int tls13_update_key(SSL *s, int send)
+int tls13_update_key(SSL *s, int sending)
 {
-    static const unsigned char application_traffic[] =
-        "application traffic secret";
+    static const unsigned char application_traffic[] = "traffic upd";
     const EVP_MD *md = ssl_handshake_md(s);
     size_t hashlen = EVP_MD_size(md);
     unsigned char *insecret, *iv;
@@ -568,12 +565,12 @@ int tls13_update_key(SSL *s, int send)
     EVP_CIPHER_CTX *ciph_ctx;
     int ret = 0;
 
-    if (s->server == send)
+    if (s->server == sending)
         insecret = s->server_app_traffic_secret;
     else
         insecret = s->client_app_traffic_secret;
 
-    if (send) {
+    if (sending) {
         iv = s->write_iv;
         ciph_ctx = s->enc_write_ctx;
         RECORD_LAYER_reset_write_sequence(&s->rlayer);
@@ -583,7 +580,7 @@ int tls13_update_key(SSL *s, int send)
         RECORD_LAYER_reset_read_sequence(&s->rlayer);
     }
 
-    if (!derive_secret_key_and_iv(s, send, ssl_handshake_md(s),
+    if (!derive_secret_key_and_iv(s, sending, ssl_handshake_md(s),
                                   s->s3->tmp.new_sym_enc, insecret, NULL,
                                   application_traffic,
                                   sizeof(application_traffic) - 1, secret, iv,
@@ -605,3 +602,41 @@ int tls13_alert_code(int code)
 
     return tls1_alert_code(code);
 }
+
+int tls13_export_keying_material(SSL *s, unsigned char *out, size_t olen,
+                                 const char *label, size_t llen,
+                                 const unsigned char *context,
+                                 size_t contextlen, int use_context)
+{
+    unsigned char exportsecret[EVP_MAX_MD_SIZE];
+    static const unsigned char exporterlabel[] = "exporter";
+    unsigned char hash[EVP_MAX_MD_SIZE], data[EVP_MAX_MD_SIZE];
+    const EVP_MD *md = ssl_handshake_md(s);
+    EVP_MD_CTX *ctx = EVP_MD_CTX_new();
+    unsigned int hashsize, datalen;
+    int ret = 0;
+
+    if (ctx == NULL || !SSL_is_init_finished(s))
+        goto err;
+
+    if (!use_context)
+        contextlen = 0;
+
+    if (EVP_DigestInit_ex(ctx, md, NULL) <= 0
+            || EVP_DigestUpdate(ctx, context, contextlen) <= 0
+            || EVP_DigestFinal_ex(ctx, hash, &hashsize) <= 0
+            || EVP_DigestInit_ex(ctx, md, NULL) <= 0
+            || EVP_DigestFinal_ex(ctx, data, &datalen) <= 0
+            || !tls13_hkdf_expand(s, md, s->exporter_master_secret,
+                                  (const unsigned char *)label, llen,
+                                  data, datalen, exportsecret, hashsize)
+            || !tls13_hkdf_expand(s, md, exportsecret, exporterlabel,
+                                  sizeof(exporterlabel) - 1, hash, hashsize,
+                                  out, olen))
+        goto err;
+
+    ret = 1;
+ err:
+    EVP_MD_CTX_free(ctx);
+    return ret;
+}