Split out ECDHE from tls_process_key_exchange()

Continuing from the previous commit. Refactor tls_process_key_exchange() to
split out into a separate function the ECDHE aspects.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

ssl/statem/statem_clnt.c

@@ -1489,48 +1489,9 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
 #endif
 }
 
-MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
+static int tls_process_ske_ecdhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey, int *al)
 {
-    EVP_MD_CTX *md_ctx;
-    int al = -1;
-    long alg_k, alg_a;
-    EVP_PKEY *pkey = NULL;
-    PACKET save_param_start, signature;
-
-    md_ctx = EVP_MD_CTX_new();
-    if (md_ctx == NULL) {
-        al = SSL_AD_INTERNAL_ERROR;
-        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
-        goto f_err;
-    }
-
-    alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
-
-    save_param_start = *pkt;
-
-#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)
-    EVP_PKEY_free(s->s3->peer_tmp);
-    s->s3->peer_tmp = NULL;
-#endif
-
-    alg_a = s->s3->tmp.new_cipher->algorithm_auth;
-
-    if (alg_k & SSL_PSK) {
-        if (!tls_process_ske_psk_preamble(s, pkt, &al))
-            goto err;
-    }
-
-    /* Nothing else to do for plain PSK or RSAPSK */
-    if (alg_k & (SSL_kPSK | SSL_kRSAPSK)) {
-    } else if (alg_k & SSL_kSRP) {
-        if (!tls_process_ske_srp(s, pkt, &pkey, &al))
-            goto err;
-    } else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
-        if (!tls_process_ske_dhe(s, pkt, &pkey, &al))
-            goto err;
-    }
 #ifndef OPENSSL_NO_EC
-    else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
     PACKET encoded_pt;
     const unsigned char *ecparams;
     int curve_nid;
@@ -1542,24 +1503,26 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
      * ECParameters in this case is just three bytes.
      */
     if (!PACKET_get_bytes(pkt, &ecparams, 3)) {
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_TOO_SHORT);
-            goto f_err;
+        return 0;
     }
     /*
      * Check curve is one of our preferences, if not server has sent an
      * invalid curve. ECParameters is 3 bytes.
      */
     if (!tls1_check_curve(s, ecparams, 3)) {
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_WRONG_CURVE);
-            goto f_err;
+        return 0;
     }
 
     curve_nid = tls1_ec_curve_id2nid(*(ecparams + 2));
     if (curve_nid  == 0) {
-            al = SSL_AD_INTERNAL_ERROR;
+        *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE,
                SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
-            goto f_err;
+        return 0;
     }
 
     /* Set up EVP_PKEY with named curve as parameters */
@@ -1568,24 +1531,26 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
         || EVP_PKEY_paramgen_init(pctx) <= 0
         || EVP_PKEY_CTX_set_ec_paramgen_curve_nid(pctx, curve_nid) <= 0
         || EVP_PKEY_paramgen(pctx, &s->s3->peer_tmp) <= 0) {
-            al = SSL_AD_INTERNAL_ERROR;
+        *al = SSL_AD_INTERNAL_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_EVP_LIB);
         EVP_PKEY_CTX_free(pctx);
-            goto f_err;
+        return 0;
     }
     EVP_PKEY_CTX_free(pctx);
     pctx = NULL;
 
     if (!PACKET_get_length_prefixed_1(pkt, &encoded_pt)) {
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_LENGTH_MISMATCH);
-            goto f_err;
+        return 0;
     }
 
     if (EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(s->s3->peer_tmp),
                        PACKET_data(&encoded_pt),
                        PACKET_remaining(&encoded_pt), NULL) == 0) {
+        *al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_ECPOINT);
-            goto f_err;
+        return 0;
     }
 
     /*
@@ -1593,22 +1558,67 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
      * ECParameters in the server key exchange message. We do support RSA
      * and ECDSA.
      */
-        if (0) ;
-# ifndef OPENSSL_NO_RSA
-        else if (alg_a & SSL_aRSA)
-            pkey = X509_get0_pubkey(s->session->peer);
-# endif
-# ifndef OPENSSL_NO_EC
-        else if (alg_a & SSL_aECDSA)
-            pkey = X509_get0_pubkey(s->session->peer);
-# endif
+    if (s->s3->tmp.new_cipher->algorithm_auth & SSL_aECDSA)
+        *pkey = X509_get0_pubkey(s->session->peer);
+    else if (s->s3->tmp.new_cipher->algorithm_auth & SSL_aRSA)
+        *pkey = X509_get0_pubkey(s->session->peer);
     /* else anonymous ECDH, so no certificate or pkey. */
+
+    return 1;
+#else
+    SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+    *al = SSL_AD_INTERNAL_ERROR;
+    return 0;
+#endif
+}
+
+MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
+{
+    EVP_MD_CTX *md_ctx;
+    int al = -1;
+    long alg_k, alg_a;
+    EVP_PKEY *pkey = NULL;
+    PACKET save_param_start, signature;
+
+    md_ctx = EVP_MD_CTX_new();
+    if (md_ctx == NULL) {
+        al = SSL_AD_INTERNAL_ERROR;
+        SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+        goto f_err;
+    }
+
+    alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
+
+    save_param_start = *pkt;
+
+#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)
+    EVP_PKEY_free(s->s3->peer_tmp);
+    s->s3->peer_tmp = NULL;
+#endif
+
+    alg_a = s->s3->tmp.new_cipher->algorithm_auth;
+
+    if (alg_k & SSL_PSK) {
+        if (!tls_process_ske_psk_preamble(s, pkt, &al))
+            goto err;
+    }
+
+    /* Nothing else to do for plain PSK or RSAPSK */
+    if (alg_k & (SSL_kPSK | SSL_kRSAPSK)) {
+    } else if (alg_k & SSL_kSRP) {
+        if (!tls_process_ske_srp(s, pkt, &pkey, &al))
+            goto err;
+    } else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
+        if (!tls_process_ske_dhe(s, pkt, &pkey, &al))
+            goto err;
+    } else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
+        if (!tls_process_ske_ecdhe(s, pkt, &pkey, &al))
+            goto err;
     } else if (alg_k) {
         al = SSL_AD_UNEXPECTED_MESSAGE;
         SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_UNEXPECTED_MESSAGE);
         goto f_err;
     }
-#endif                          /* !OPENSSL_NO_EC */
 
     /* if it was signed, check the signature */
     if (pkey != NULL) {