Add support for ECDHE with X25519.

Testing of an earlier revision by naddy@.

ok beck@

7 files changed, 316 insertions, 91 deletions

diff --git a/src/lib/libssl/s3_clnt.c b/src/lib/libssl/s3_clnt.c
index be6e461a1e..07457e95a7 100644
--- a/src/lib/libssl/s3_clnt.c
+++ b/src/lib/libssl/s3_clnt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_clnt.c,v 1.156 2016/12/18 13:52:53 jsing Exp $ */
+/* $OpenBSD: s3_clnt.c,v 1.157 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -156,6 +156,7 @@
 
 #include <openssl/bn.h>
 #include <openssl/buffer.h>
+#include <openssl/curve25519.h>
 #include <openssl/dh.h>
 #include <openssl/evp.h>
 #include <openssl/md5.h>
@@ -1184,19 +1185,99 @@ ssl3_get_server_kex_dhe(SSL *s, EVP_PKEY **pkey, unsigned char **pp, long *nn)
 }
 
 static int
+ssl3_get_server_kex_ecdhe_ecp(SSL *s, SESS_CERT *sc, int nid, CBS *public)
+{
+        const EC_GROUP *group;
+        EC_GROUP *ngroup = NULL;
+        EC_POINT *point = NULL;
+        BN_CTX *bn_ctx = NULL;
+        EC_KEY *ecdh = NULL;
+        int ret = -1;
+
+        /*
+         * Extract the server's ephemeral ECDH public key.
+         */
+
+        if ((ecdh = EC_KEY_new()) == NULL) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+                goto err;
+        }
+
+        if ((ngroup = EC_GROUP_new_by_curve_name(nid)) == NULL) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_EC_LIB);
+                goto err;
+        }
+        if (EC_KEY_set_group(ecdh, ngroup) == 0) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_EC_LIB);
+                goto err;
+        }
+
+        group = EC_KEY_get0_group(ecdh);
+
+        if ((point = EC_POINT_new(group)) == NULL ||
+            (bn_ctx = BN_CTX_new()) == NULL) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+                goto err;
+        }
+
+        if (EC_POINT_oct2point(group, point, CBS_data(public),
+            CBS_len(public), bn_ctx) == 0) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_ECPOINT);
+                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+                goto err;
+        }
+
+        EC_KEY_set_public_key(ecdh, point);
+        sc->peer_ecdh_tmp = ecdh;
+        ecdh = NULL;
+
+        ret = 1;
+
+ err:
+        BN_CTX_free(bn_ctx);
+        EC_GROUP_free(ngroup);
+        EC_POINT_free(point);
+        EC_KEY_free(ecdh);
+
+        return (ret);
+}
+
+static int
+ssl3_get_server_kex_ecdhe_ecx(SSL *s, SESS_CERT *sc, int nid, CBS *public)
+{
+        size_t outlen;
+
+        if (nid != NID_X25519) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+                goto err;
+        }
+
+        if (CBS_len(public) != X25519_KEY_LENGTH) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_ECPOINT);
+                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+                goto err;
+        }
+
+        if (!CBS_stow(public, &sc->peer_x25519_tmp, &outlen)) {
+                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+                goto err;
+        }
+
+        return (1);
+
+ err:
+        return (-1);
+}
+
+static int
 ssl3_get_server_kex_ecdhe(SSL *s, EVP_PKEY **pkey, unsigned char **pp, long *nn)
 {
-        CBS cbs, ecpoint;
+        CBS cbs, public;
         uint8_t curve_type;
         uint16_t curve_id;
-        EC_POINT *srvr_ecpoint = NULL;
-        EC_KEY *ecdh = NULL;
-        BN_CTX *bn_ctx = NULL;
-        const EC_GROUP *group;
-        EC_GROUP *ngroup = NULL;
         SESS_CERT *sc;
-        int curve_nid;
         long alg_a;
+        int nid;
         int al;
 
         alg_a = s->s3->tmp.new_cipher->algorithm_auth;
@@ -1207,15 +1288,6 @@ ssl3_get_server_kex_ecdhe(SSL *s, EVP_PKEY **pkey, unsigned char **pp, long *nn)
 
         CBS_init(&cbs, *pp, *nn);
 
-        /*
-         * Extract EC parameters and the server's ephemeral ECDH public key.
-         */
-
-        if ((ecdh = EC_KEY_new()) == NULL) {
-                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
-                goto err;
-        }
-
         /* Only named curves are supported. */
         if (!CBS_get_u8(&cbs, &curve_type) ||
             curve_type != NAMED_CURVE_TYPE ||
@@ -1235,39 +1307,22 @@ ssl3_get_server_kex_ecdhe(SSL *s, EVP_PKEY **pkey, unsigned char **pp, long *nn)
                 goto f_err;
         }
 
-        if ((curve_nid = tls1_ec_curve_id2nid(curve_id)) == 0) {
+        if ((nid = tls1_ec_curve_id2nid(curve_id)) == 0) {
                 al = SSL_AD_INTERNAL_ERROR;
                 SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE,
                     SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS);
                 goto f_err;
         }
 
-        if ((ngroup = EC_GROUP_new_by_curve_name(curve_nid)) == NULL) {
-                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_EC_LIB);
-                goto err;
-        }
-        if (EC_KEY_set_group(ecdh, ngroup) == 0) {
-                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_EC_LIB);
-                goto err;
-        }
-
-        group = EC_KEY_get0_group(ecdh);
-
-        /* Next, get the encoded ECPoint */
-        if ((srvr_ecpoint = EC_POINT_new(group)) == NULL ||
-            (bn_ctx = BN_CTX_new()) == NULL) {
-                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
-                goto err;
-        }
-
-        if (!CBS_get_u8_length_prefixed(&cbs, &ecpoint))
+        if (!CBS_get_u8_length_prefixed(&cbs, &public))
                 goto truncated;
 
-        if (EC_POINT_oct2point(group, srvr_ecpoint, CBS_data(&ecpoint),
-            CBS_len(&ecpoint), bn_ctx) == 0) {
-                al = SSL_AD_DECODE_ERROR;
-                SSLerr(SSL_F_SSL3_GET_KEY_EXCHANGE, SSL_R_BAD_ECPOINT);
-                goto f_err;
+        if (nid == NID_X25519) {
+                if (ssl3_get_server_kex_ecdhe_ecx(s, sc, nid, &public) != 1)
+                        goto err;
+        } else {
+                if (ssl3_get_server_kex_ecdhe_ecp(s, sc, nid, &public) != 1)
+                        goto err;
         }
 
         /*
@@ -1283,13 +1338,6 @@ ssl3_get_server_kex_ecdhe(SSL *s, EVP_PKEY **pkey, unsigned char **pp, long *nn)
                 /* XXX - Anonymous ECDH, so no certificate or pkey. */
                 *pkey = NULL;
 
-        EC_KEY_set_public_key(ecdh, srvr_ecpoint);
-        sc->peer_ecdh_tmp = ecdh;
-
-        BN_CTX_free(bn_ctx);
-        EC_GROUP_free(ngroup);
-        EC_POINT_free(srvr_ecpoint);
-
         *nn = CBS_len(&cbs);
         *pp = (unsigned char *)CBS_data(&cbs);
 
@@ -1303,11 +1351,6 @@ ssl3_get_server_kex_ecdhe(SSL *s, EVP_PKEY **pkey, unsigned char **pp, long *nn)
         ssl3_send_alert(s, SSL3_AL_FATAL, al);
 
  err:
-        BN_CTX_free(bn_ctx);
-        EC_GROUP_free(ngroup);
-        EC_POINT_free(srvr_ecpoint);
-        EC_KEY_free(ecdh);
-
         return (-1);
 }
 
@@ -1360,6 +1403,9 @@ ssl3_get_server_key_exchange(SSL *s)
 
                 EC_KEY_free(s->session->sess_cert->peer_ecdh_tmp);
                 s->session->sess_cert->peer_ecdh_tmp = NULL;
+
+                free(s->session->sess_cert->peer_x25519_tmp);
+                s->session->sess_cert->peer_x25519_tmp = NULL;
         } else {
                 s->session->sess_cert = ssl_sess_cert_new();
                 if (s->session->sess_cert == NULL)
@@ -2010,11 +2056,11 @@ err:
 }
 
 static int
-ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
+ssl3_send_client_kex_ecdhe_ecp(SSL *s, SESS_CERT *sc, CBB *cbb)
 {
-        EC_KEY *clnt_ecdh = NULL;
-        const EC_GROUP *srvr_group = NULL;
-        const EC_POINT *srvr_ecpoint = NULL;
+        const EC_GROUP *group = NULL;
+        const EC_POINT *point = NULL;
+        EC_KEY *ecdh = NULL;
         BN_CTX *bn_ctx = NULL;
         unsigned char *key = NULL;
         unsigned char *data;
@@ -2023,40 +2069,30 @@ ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
         int ret = -1;
         CBB ecpoint;
 
-        if (sess_cert->peer_ecdh_tmp == NULL) {
-                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+        if ((group = EC_KEY_get0_group(sc->peer_ecdh_tmp)) == NULL ||
+            (point = EC_KEY_get0_public_key(sc->peer_ecdh_tmp)) == NULL) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,
                     ERR_R_INTERNAL_ERROR);
                 goto err;
         }
 
-        srvr_group = EC_KEY_get0_group(sess_cert->peer_ecdh_tmp);
-        srvr_ecpoint = EC_KEY_get0_public_key(sess_cert->peer_ecdh_tmp);
-
-        if (srvr_group == NULL || srvr_ecpoint == NULL) {
-                SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,
-                    ERR_R_INTERNAL_ERROR);
-                goto err;
-        }
-
-        if ((clnt_ecdh = EC_KEY_new()) == NULL) {
+        if ((ecdh = EC_KEY_new()) == NULL) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,
                     ERR_R_MALLOC_FAILURE);
                 goto err;
         }
 
-        if (!EC_KEY_set_group(clnt_ecdh, srvr_group)) {
+        if (!EC_KEY_set_group(ecdh, group)) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
                 goto err;
         }
 
         /* Generate a new ECDH key pair. */
-        if (!(EC_KEY_generate_key(clnt_ecdh))) {
+        if (!(EC_KEY_generate_key(ecdh))) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                 goto err;
         }
-        key_size = ECDH_size(clnt_ecdh);
-        if (key_size <= 0) {
+        if ((key_size = ECDH_size(ecdh)) <= 0) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                 goto err;
         }
@@ -2064,7 +2100,7 @@ ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,
                     ERR_R_MALLOC_FAILURE);
         }
-        key_len = ECDH_compute_key(key, key_size, srvr_ecpoint, clnt_ecdh, NULL);
+        key_len = ECDH_compute_key(key, key_size, point, ecdh, NULL);
         if (key_len <= 0) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB);
                 goto err;
@@ -2075,8 +2111,7 @@ ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
             s->method->ssl3_enc->generate_master_secret(s,
                 s->session->master_key, key, key_len);
 
-        encoded_len = EC_POINT_point2oct(srvr_group,
-            EC_KEY_get0_public_key(clnt_ecdh),
+        encoded_len = EC_POINT_point2oct(group, EC_KEY_get0_public_key(ecdh),
             POINT_CONVERSION_UNCOMPRESSED, NULL, 0, NULL);
         if (encoded_len == 0) {
                 SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE, ERR_R_ECDH_LIB);
@@ -2094,7 +2129,7 @@ ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
                 goto err;
         if (!CBB_add_space(&ecpoint, &data, encoded_len))
                 goto err;
-        if (EC_POINT_point2oct(srvr_group, EC_KEY_get0_public_key(clnt_ecdh),
+        if (EC_POINT_point2oct(group, EC_KEY_get0_public_key(ecdh),
             POINT_CONVERSION_UNCOMPRESSED, data, encoded_len,
             bn_ctx) == 0)
                 goto err;
@@ -2108,13 +2143,78 @@ ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
                 explicit_bzero(key, key_size);
         free(key);
 
-        BN_CTX_free(bn_ctx);
-        EC_KEY_free(clnt_ecdh);
+        return (ret);
+}
+
+static int
+ssl3_send_client_kex_ecdhe_ecx(SSL *s, SESS_CERT *sc, CBB *cbb)
+{
+        uint8_t *public_key = NULL, *private_key = NULL, *shared_key = NULL;
+        int ret = -1;
+        CBB ecpoint;
+
+        /* Generate X25519 key pair and derive shared key. */
+        if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL)
+                goto err;
+        if ((private_key = malloc(X25519_KEY_LENGTH)) == NULL)
+                goto err;
+        if ((shared_key = malloc(X25519_KEY_LENGTH)) == NULL)
+                goto err;
+        X25519_keypair(public_key, private_key);
+        if (!X25519(shared_key, private_key, sc->peer_x25519_tmp))
+                goto err;
+
+        /* Serialize the public key. */
+        if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
+                goto err;
+        if (!CBB_add_bytes(&ecpoint, public_key, X25519_KEY_LENGTH))
+                goto err;
+        if (!CBB_flush(cbb))
+                goto err;
+
+        /* Generate master key from the result. */
+        s->session->master_key_length =
+            s->method->ssl3_enc->generate_master_secret(s,
+                s->session->master_key, shared_key, X25519_KEY_LENGTH);
+
+        ret = 1;
+
+ err:
+        if (private_key != NULL)
+                explicit_bzero(private_key, X25519_KEY_LENGTH);
+        if (shared_key != NULL)
+                explicit_bzero(shared_key, X25519_KEY_LENGTH);
+
+        free(public_key);
+        free(private_key);
+        free(shared_key);
 
         return (ret);
 }
 
 static int
+ssl3_send_client_kex_ecdhe(SSL *s, SESS_CERT *sc, CBB *cbb)
+{
+        if (sc->peer_x25519_tmp != NULL) {
+                if (ssl3_send_client_kex_ecdhe_ecx(s, sc, cbb) != 1)
+                        goto err;
+        } else if (sc->peer_ecdh_tmp != NULL) {
+                if (ssl3_send_client_kex_ecdhe_ecp(s, sc, cbb) != 1)
+                        goto err;
+        } else {
+                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
+                SSLerr(SSL_F_SSL3_SEND_CLIENT_KEY_EXCHANGE,
+                    ERR_R_INTERNAL_ERROR);
+                goto err;
+        }
+
+        return (1);
+
+ err:
+        return (-1);
+}
+
+static int
 ssl3_send_client_kex_gost(SSL *s, SESS_CERT *sess_cert, CBB *cbb)
 {
         unsigned char premaster_secret[32], shared_ukm[32], tmp[256];
diff --git a/src/lib/libssl/s3_lib.c b/src/lib/libssl/s3_lib.c
index db9292172d..212de5f7a4 100644
--- a/src/lib/libssl/s3_lib.c
+++ b/src/lib/libssl/s3_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_lib.c,v 1.113 2016/12/06 13:17:52 jsing Exp $ */
+/* $OpenBSD: s3_lib.c,v 1.114 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -151,6 +151,7 @@
 #include <limits.h>
 #include <stdio.h>
 
+#include <openssl/curve25519.h>
 #include <openssl/dh.h>
 #include <openssl/md5.h>
 #include <openssl/objects.h>
@@ -1835,6 +1836,10 @@ ssl3_free(SSL *s)
         DH_free(s->s3->tmp.dh);
         EC_KEY_free(s->s3->tmp.ecdh);
 
+        if (s->s3->tmp.x25519 != NULL)
+                explicit_bzero(s->s3->tmp.x25519, X25519_KEY_LENGTH);
+        free(s->s3->tmp.x25519);
+
         if (s->s3->tmp.ca_names != NULL)
                 sk_X509_NAME_pop_free(s->s3->tmp.ca_names, X509_NAME_free);
         BIO_free(s->s3->handshake_buffer);
@@ -1861,6 +1866,11 @@ ssl3_clear(SSL *s)
         EC_KEY_free(s->s3->tmp.ecdh);
         s->s3->tmp.ecdh = NULL;
 
+        if (s->s3->tmp.x25519 != NULL)
+                explicit_bzero(s->s3->tmp.x25519, X25519_KEY_LENGTH);
+        free(s->s3->tmp.x25519);
+        s->s3->tmp.x25519 = NULL;
+
         rp = s->s3->rbuf.buf;
         wp = s->s3->wbuf.buf;
         rlen = s->s3->rbuf.len;
diff --git a/src/lib/libssl/s3_srvr.c b/src/lib/libssl/s3_srvr.c
index 3dd085115d..8e3dc11fc1 100644
--- a/src/lib/libssl/s3_srvr.c
+++ b/src/lib/libssl/s3_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_srvr.c,v 1.137 2016/12/07 13:18:38 jsing Exp $ */
+/* $OpenBSD: s3_srvr.c,v 1.138 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -154,6 +154,7 @@
 
 #include <openssl/bn.h>
 #include <openssl/buffer.h>
+#include <openssl/curve25519.h>
 #include <openssl/evp.h>
 #include <openssl/dh.h>
 #ifndef OPENSSL_NO_GOST
@@ -1268,8 +1269,8 @@ ssl3_send_server_kex_dhe(SSL *s, CBB *cbb)
         return (-1);
 }
 
-int
-ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
+static int
+ssl3_send_server_kex_ecdhe_ecp(SSL *s, int nid, CBB *cbb)
 {
         CBB ecpoint;
         unsigned char *data;
@@ -1283,7 +1284,6 @@ ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
 
         ecdhp = s->cert->ecdh_tmp;
         if (s->cert->ecdh_tmp_auto != 0) {
-                int nid = tls1_get_shared_curve(s);
                 if (nid != NID_undef)
                         ecdhp = EC_KEY_new_by_curve_name(nid);
         } else if (ecdhp == NULL && s->cert->ecdh_tmp_cb != NULL) {
@@ -1404,6 +1404,65 @@ ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
         return (-1);
 }
 
+static int
+ssl3_send_server_kex_ecdhe_ecx(SSL *s, int nid, CBB *cbb)
+{
+        uint8_t *public_key = NULL;
+        int curve_id;
+        CBB ecpoint;
+        int ret = -1;
+
+        /* Generate an X25519 key pair. */
+        if (s->s3->tmp.x25519 != NULL) {
+                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
+                    ERR_R_INTERNAL_ERROR);
+                goto err;
+        }
+        if ((s->s3->tmp.x25519 = malloc(X25519_KEY_LENGTH)) == NULL)
+                goto err;
+        if ((public_key = malloc(X25519_KEY_LENGTH)) == NULL)
+                goto err;
+        X25519_keypair(public_key, s->s3->tmp.x25519);
+
+        /* Serialize public key. */
+        if ((curve_id = tls1_ec_nid2curve_id(nid)) == 0) {
+                SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,
+                    SSL_R_UNSUPPORTED_ELLIPTIC_CURVE);
+                goto err;
+        }
+
+        if (!CBB_add_u8(cbb, NAMED_CURVE_TYPE))
+                goto err;
+        if (!CBB_add_u16(cbb, curve_id))
+                goto err;
+        if (!CBB_add_u8_length_prefixed(cbb, &ecpoint))
+                goto err;
+        if (!CBB_add_bytes(&ecpoint, public_key, X25519_KEY_LENGTH))
+                goto err;
+        if (!CBB_flush(cbb))
+                goto err;
+
+        ret = 1;
+
+ err:
+        free(public_key);
+
+        return (ret);
+}
+
+static int
+ssl3_send_server_kex_ecdhe(SSL *s, CBB *cbb)
+{
+        int nid;
+
+        nid = tls1_get_shared_curve(s);
+
+        if (s->cert->ecdh_tmp_auto != 0 && nid == NID_X25519)
+                return ssl3_send_server_kex_ecdhe_ecx(s, nid, cbb);
+
+        return ssl3_send_server_kex_ecdhe_ecp(s, nid, cbb);
+}
+
 int
 ssl3_send_server_key_exchange(SSL *s)
 {
@@ -1822,7 +1881,7 @@ ssl3_get_client_kex_dhe(SSL *s, unsigned char *p, long n)
 }
 
 static int
-ssl3_get_client_kex_ecdhe(SSL *s, unsigned char *p, long n)
+ssl3_get_client_kex_ecdhe_ecp(SSL *s, unsigned char *p, long n)
 {
         EC_KEY *srvr_ecdh = NULL;
         EVP_PKEY *clnt_pub_pkey = NULL;
@@ -1971,6 +2030,54 @@ ssl3_get_client_kex_ecdhe(SSL *s, unsigned char *p, long n)
 }
 
 static int
+ssl3_get_client_kex_ecdhe_ecx(SSL *s, unsigned char *p, long n)
+{
+        uint8_t *shared_key = NULL;
+        CBS cbs, ecpoint;
+        int ret = -1;
+
+        if (n < 0)
+                goto err;
+
+        CBS_init(&cbs, p, n);
+        if (!CBS_get_u8_length_prefixed(&cbs, &ecpoint))
+                goto err;
+        if (CBS_len(&ecpoint) != X25519_KEY_LENGTH)
+                goto err;
+
+        if ((shared_key = malloc(X25519_KEY_LENGTH)) == NULL)
+                goto err;
+        if (!X25519(shared_key, s->s3->tmp.x25519, CBS_data(&ecpoint)))
+                goto err;
+
+        explicit_bzero(s->s3->tmp.x25519, X25519_KEY_LENGTH);
+        free(s->s3->tmp.x25519);
+        s->s3->tmp.x25519 = NULL;
+
+        s->session->master_key_length =
+            s->method->ssl3_enc->generate_master_secret(
+                s, s->session->master_key, shared_key, X25519_KEY_LENGTH);
+
+        ret = 1;
+
+ err:
+        if (shared_key != NULL)
+                explicit_bzero(shared_key, X25519_KEY_LENGTH);
+        free(shared_key);
+
+        return (ret);
+}
+
+static int
+ssl3_get_client_kex_ecdhe(SSL *s, unsigned char *p, long n)
+{
+        if (s->s3->tmp.x25519 != NULL)
+                return ssl3_get_client_kex_ecdhe_ecx(s, p, n);
+
+        return ssl3_get_client_kex_ecdhe_ecp(s, p, n);
+}
+
+static int
 ssl3_get_client_kex_gost(SSL *s, unsigned char *p, long n)
 {
 
diff --git a/src/lib/libssl/ssl3.h b/src/lib/libssl/ssl3.h
index 5ec2fe6f88..90fcae7914 100644
--- a/src/lib/libssl/ssl3.h
+++ b/src/lib/libssl/ssl3.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl3.h,v 1.41 2015/07/19 06:23:51 doug Exp $ */
+/* $OpenBSD: ssl3.h,v 1.42 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -440,6 +440,8 @@ typedef struct ssl3_state_st {
 
                 EC_KEY *ecdh; /* holds short lived ECDH key */
 
+                uint8_t *x25519;
+
                 /* used when SSL_ST_FLUSH_DATA is entered */
                 int next_state;
 
diff --git a/src/lib/libssl/ssl_cert.c b/src/lib/libssl/ssl_cert.c
index 7e92812e56..294745c9f9 100644
--- a/src/lib/libssl/ssl_cert.c
+++ b/src/lib/libssl/ssl_cert.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_cert.c,v 1.52 2016/03/11 07:08:45 mmcc Exp $ */
+/* $OpenBSD: ssl_cert.c,v 1.53 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -403,6 +403,7 @@ ssl_sess_cert_free(SESS_CERT *sc)
 
         DH_free(sc->peer_dh_tmp);
         EC_KEY_free(sc->peer_ecdh_tmp);
+        free(sc->peer_x25519_tmp);
 
         free(sc);
 }
diff --git a/src/lib/libssl/ssl_locl.h b/src/lib/libssl/ssl_locl.h
index d7484dd7a0..858be71627 100644
--- a/src/lib/libssl/ssl_locl.h
+++ b/src/lib/libssl/ssl_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_locl.h,v 1.140 2016/12/18 13:52:53 jsing Exp $ */
+/* $OpenBSD: ssl_locl.h,v 1.141 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -468,6 +468,7 @@ typedef struct sess_cert_st {
 
         DH *peer_dh_tmp;
         EC_KEY *peer_ecdh_tmp;
+        uint8_t *peer_x25519_tmp;
 
         int references; /* actually always 1 at the moment */
 } SESS_CERT;
diff --git a/src/lib/libssl/t1_lib.c b/src/lib/libssl/t1_lib.c
index 0a5958341b..4e4fa21687 100644
--- a/src/lib/libssl/t1_lib.c
+++ b/src/lib/libssl/t1_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t1_lib.c,v 1.95 2016/12/18 13:52:53 jsing Exp $ */
+/* $OpenBSD: t1_lib.c,v 1.96 2016/12/21 16:44:31 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -241,7 +241,8 @@ static int nid_list[] = {
         NID_secp521r1,          /* secp521r1 (25) */
         NID_brainpoolP256r1,    /* brainpoolP256r1 (26) */
         NID_brainpoolP384r1,    /* brainpoolP384r1 (27) */
-        NID_brainpoolP512r1     /* brainpoolP512r1 (28) */
+        NID_brainpoolP512r1,    /* brainpoolP512r1 (28) */
+        NID_X25519,             /* X25519 (29) */
 };
 
 static const uint8_t ecformats_default[] = {
@@ -251,6 +252,7 @@ static const uint8_t ecformats_default[] = {
 };
 
 static const uint16_t eccurves_default[] = {
+        29,                     /* X25519 (29) */
         14,                     /* sect571r1 (14) */
         13,                     /* sect571k1 (13) */
         25,                     /* secp521r1 (25) */
@@ -352,6 +354,8 @@ tls1_ec_nid2curve_id(int nid)
                 return 27;
         case NID_brainpoolP512r1: /* brainpoolP512r1 (28) */
                 return 28;
+        case NID_X25519:                /* X25519 (29) */
+                return 29;
         default:
                 return 0;
         }