dh: Add diffie-hellman-group16-sha512 support

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

11 files changed, 184 insertions, 47 deletions

diff --git a/include/libssh/crypto.h b/include/libssh/crypto.h
index 490910fa..fdf23191 100644
--- a/include/libssh/crypto.h
+++ b/include/libssh/crypto.h
@@ -62,7 +62,9 @@ enum ssh_key_exchange_e {
   /* curve25519-sha256@libssh.org */
   SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG,
   /* curve25519-sha256 */
-  SSH_KEX_CURVE25519_SHA256
+  SSH_KEX_CURVE25519_SHA256,
+  /* diffie-hellman-group16-sha512 */
+  SSH_KEX_DH_GROUP16_SHA512,
 };
 
 enum ssh_cipher_e {
diff --git a/src/client.c b/src/client.c
index a4745380..2b1d5a61 100644
--- a/src/client.c
+++ b/src/client.c
@@ -250,6 +250,7 @@ static int dh_handshake(ssh_session session) {
       switch(session->next_crypto->kex_type){
         case SSH_KEX_DH_GROUP1_SHA1:
         case SSH_KEX_DH_GROUP14_SHA1:
+        case SSH_KEX_DH_GROUP16_SHA512:
           rc = ssh_client_dh_init(session);
           break;
 #ifdef HAVE_ECDH
diff --git a/src/dh.c b/src/dh.c
index 19645d52..5b607abe 100644
--- a/src/dh.c
+++ b/src/dh.c
@@ -112,14 +112,71 @@ static unsigned char p_group14_value[] = {
 
 #define P_GROUP14_LEN 256 /* Size in bytes of the p number for group 14 */
 
+static unsigned char p_group16_value[] = {
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2,
+    0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1,
+    0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6,
+    0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD,
+    0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D,
+    0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45,
+    0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9,
+    0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED,
+    0xEE, 0x38, 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11,
+    0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE4, 0x5B, 0x3D,
+    0xC2, 0x00, 0x7C, 0xB8, 0xA1, 0x63, 0xBF, 0x05, 0x98, 0xDA, 0x48, 0x36,
+    0x1C, 0x55, 0xD3, 0x9A, 0x69, 0x16, 0x3F, 0xA8, 0xFD, 0x24, 0xCF, 0x5F,
+    0x83, 0x65, 0x5D, 0x23, 0xDC, 0xA3, 0xAD, 0x96, 0x1C, 0x62, 0xF3, 0x56,
+    0x20, 0x85, 0x52, 0xBB, 0x9E, 0xD5, 0x29, 0x07, 0x70, 0x96, 0x96, 0x6D,
+    0x67, 0x0C, 0x35, 0x4E, 0x4A, 0xBC, 0x98, 0x04, 0xF1, 0x74, 0x6C, 0x08,
+    0xCA, 0x18, 0x21, 0x7C, 0x32, 0x90, 0x5E, 0x46, 0x2E, 0x36, 0xCE, 0x3B,
+    0xE3, 0x9E, 0x77, 0x2C, 0x18, 0x0E, 0x86, 0x03, 0x9B, 0x27, 0x83, 0xA2,
+    0xEC, 0x07, 0xA2, 0x8F, 0xB5, 0xC5, 0x5D, 0xF0, 0x6F, 0x4C, 0x52, 0xC9,
+    0xDE, 0x2B, 0xCB, 0xF6, 0x95, 0x58, 0x17, 0x18, 0x39, 0x95, 0x49, 0x7C,
+    0xEA, 0x95, 0x6A, 0xE5, 0x15, 0xD2, 0x26, 0x18, 0x98, 0xFA, 0x05, 0x10,
+    0x15, 0x72, 0x8E, 0x5A, 0x8A, 0xAA, 0xC4, 0x2D, 0xAD, 0x33, 0x17, 0x0D,
+    0x04, 0x50, 0x7A, 0x33, 0xA8, 0x55, 0x21, 0xAB, 0xDF, 0x1C, 0xBA, 0x64,
+    0xEC, 0xFB, 0x85, 0x04, 0x58, 0xDB, 0xEF, 0x0A, 0x8A, 0xEA, 0x71, 0x57,
+    0x5D, 0x06, 0x0C, 0x7D, 0xB3, 0x97, 0x0F, 0x85, 0xA6, 0xE1, 0xE4, 0xC7,
+    0xAB, 0xF5, 0xAE, 0x8C, 0xDB, 0x09, 0x33, 0xD7, 0x1E, 0x8C, 0x94, 0xE0,
+    0x4A, 0x25, 0x61, 0x9D, 0xCE, 0xE3, 0xD2, 0x26, 0x1A, 0xD2, 0xEE, 0x6B,
+    0xF1, 0x2F, 0xFA, 0x06, 0xD9, 0x8A, 0x08, 0x64, 0xD8, 0x76, 0x02, 0x73,
+    0x3E, 0xC8, 0x6A, 0x64, 0x52, 0x1F, 0x2B, 0x18, 0x17, 0x7B, 0x20, 0x0C,
+    0xBB, 0xE1, 0x17, 0x57, 0x7A, 0x61, 0x5D, 0x6C, 0x77, 0x09, 0x88, 0xC0,
+    0xBA, 0xD9, 0x46, 0xE2, 0x08, 0xE2, 0x4F, 0xA0, 0x74, 0xE5, 0xAB, 0x31,
+    0x43, 0xDB, 0x5B, 0xFC, 0xE0, 0xFD, 0x10, 0x8E, 0x4B, 0x82, 0xD1, 0x20,
+    0xA9, 0x21, 0x08, 0x01, 0x1A, 0x72, 0x3C, 0x12, 0xA7, 0x87, 0xE6, 0xD7,
+    0x88, 0x71, 0x9A, 0x10, 0xBD, 0xBA, 0x5B, 0x26, 0x99, 0xC3, 0x27, 0x18,
+    0x6A, 0xF4, 0xE2, 0x3C, 0x1A, 0x94, 0x68, 0x34, 0xB6, 0x15, 0x0B, 0xDA,
+    0x25, 0x83, 0xE9, 0xCA, 0x2A, 0xD4, 0x4C, 0xE8, 0xDB, 0xBB, 0xC2, 0xDB,
+    0x04, 0xDE, 0x8E, 0xF9, 0x2E, 0x8E, 0xFC, 0x14, 0x1F, 0xBE, 0xCA, 0xA6,
+    0x28, 0x7C, 0x59, 0x47, 0x4E, 0x6B, 0xC0, 0x5D, 0x99, 0xB2, 0x96, 0x4F,
+    0xA0, 0x90, 0xC3, 0xA2, 0x23, 0x3B, 0xA1, 0x86, 0x51, 0x5B, 0xE7, 0xED,
+    0x1F, 0x61, 0x29, 0x70, 0xCE, 0xE2, 0xD7, 0xAF, 0xB8, 0x1B, 0xDD, 0x76,
+    0x21, 0x70, 0x48, 0x1C, 0xD0, 0x06, 0x91, 0x27, 0xD5, 0xB0, 0x5A, 0xA9,
+    0x93, 0xB4, 0xEA, 0x98, 0x8D, 0x8F, 0xDD, 0xC1, 0x86, 0xFF, 0xB7, 0xDC,
+    0x90, 0xA6, 0xC0, 0x8F, 0x4D, 0xF4, 0x35, 0xC9, 0x34, 0x06, 0x31, 0x99,
+    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
+
+#define P_GROUP16_LEN 512 /* Size in bytes of the p number for group 16 */
+
 static unsigned long g_int = 2 ;	/* G is defined as 2 by the ssh2 standards */
 static bignum g;
 static bignum p_group1;
 static bignum p_group14;
+static bignum p_group16;
 static int dh_crypto_initialized;
 
 static bignum select_p(enum ssh_key_exchange_e type) {
-    return type == SSH_KEX_DH_GROUP14_SHA1 ? p_group14 : p_group1;
+    switch(type) {
+    case SSH_KEX_DH_GROUP1_SHA1:
+        return p_group1;
+    case SSH_KEX_DH_GROUP14_SHA1:
+        return p_group14;
+    case SSH_KEX_DH_GROUP16_SHA512:
+        return p_group16;
+    default:
+        return NULL;
+    }
 }
 
 /**
@@ -153,6 +210,14 @@ int ssh_dh_init(void)
 
         return SSH_ERROR;
     }
+    bignum_bin2bn(p_group16_value, P_GROUP16_LEN, &p_group16);
+    if (p_group16 == NULL) {
+        bignum_safe_free(g);
+        bignum_safe_free(p_group1);
+        bignum_safe_free(p_group14);
+
+        return SSH_ERROR;
+    }
 #elif defined(HAVE_LIBCRYPTO)
     p_group1 = bignum_new();
     if (p_group1 == NULL) {
@@ -170,12 +235,25 @@ int ssh_dh_init(void)
         return SSH_ERROR;
     }
     bignum_bin2bn(p_group14_value, P_GROUP14_LEN, p_group14);
+
+    p_group16 = bignum_new();
+    if (p_group16 == NULL) {
+        bignum_safe_free(g);
+        bignum_safe_free(p_group1);
+        bignum_safe_free(p_group14);
+
+        return SSH_ERROR;
+    }
+    bignum_bin2bn(p_group16_value, P_GROUP16_LEN, p_group16);
 #elif defined(HAVE_LIBMBEDCRYPTO)
     p_group1 = bignum_new();
     bignum_bin2bn(p_group1_value, P_GROUP1_LEN, p_group1);
 
     p_group14 = bignum_new();
     bignum_bin2bn(p_group14_value, P_GROUP14_LEN, p_group14);
+
+    p_group16 = bignum_new();
+    bignum_bin2bn(p_group16_value, P_GROUP16_LEN, p_group16);
 #endif
     dh_crypto_initialized = 1;
 
@@ -195,53 +273,76 @@ void ssh_dh_finalize(void)
     bignum_safe_free(g);
     bignum_safe_free(p_group1);
     bignum_safe_free(p_group14);
+    bignum_safe_free(p_group16);
 
     dh_crypto_initialized = 0;
 }
 
-int ssh_dh_generate_x(ssh_session session) {
-  int keysize;
-  if (session->next_crypto->kex_type == SSH_KEX_DH_GROUP1_SHA1) {
-    keysize = 1023;
-  } else {
-    keysize = 2047;
-  }
-  session->next_crypto->x = bignum_new();
-  if (session->next_crypto->x == NULL) {
-    return -1;
-  }
+int ssh_dh_generate_x(ssh_session session)
+{
+    size_t keysize;
+
+    switch(session->next_crypto->kex_type) {
+    case SSH_KEX_DH_GROUP1_SHA1:
+        keysize = 1023;
+        break;
+    case SSH_KEX_DH_GROUP14_SHA1:
+        keysize = 2047;
+        break;
+    case SSH_KEX_DH_GROUP16_SHA512:
+        keysize = 4095;
+        break;
+    default:
+        return -1;
+    }
 
-  bignum_rand(session->next_crypto->x, keysize);
+    session->next_crypto->x = bignum_new();
+    if (session->next_crypto->x == NULL) {
+        return -1;
+    }
 
-  /* not harder than this */
+    bignum_rand(session->next_crypto->x, keysize);
+
+    /* not harder than this */
 #ifdef DEBUG_CRYPTO
-  ssh_print_bignum("x", session->next_crypto->x);
+    ssh_print_bignum("x", session->next_crypto->x);
 #endif
 
-  return 0;
+    return 0;
 }
 
 /* used by server */
-int ssh_dh_generate_y(ssh_session session) {
-  int keysize;
-  if (session->next_crypto->kex_type == SSH_KEX_DH_GROUP1_SHA1) {
-    keysize = 1023;
-  } else {
-    keysize = 2047;
-  }
-  session->next_crypto->y = bignum_new();
-  if (session->next_crypto->y == NULL) {
-    return -1;
-  }
+int ssh_dh_generate_y(ssh_session session)
+{
+    size_t keysize;
+
+    switch(session->next_crypto->kex_type) {
+    case SSH_KEX_DH_GROUP1_SHA1:
+        keysize = 1023;
+        break;
+    case SSH_KEX_DH_GROUP14_SHA1:
+        keysize = 2047;
+        break;
+    case SSH_KEX_DH_GROUP16_SHA512:
+        keysize = 4095;
+        break;
+    default:
+        return -1;
+    }
+
+    session->next_crypto->y = bignum_new();
+    if (session->next_crypto->y == NULL) {
+        return -1;
+    }
 
-  bignum_rand(session->next_crypto->y, keysize);
+    bignum_rand(session->next_crypto->y, keysize);
 
-  /* not harder than this */
+    /* not harder than this */
 #ifdef DEBUG_CRYPTO
-  ssh_print_bignum("y", session->next_crypto->y);
+    ssh_print_bignum("y", session->next_crypto->y);
 #endif
 
-  return 0;
+    return 0;
 }
 
 /* used by server */
@@ -597,8 +698,10 @@ int ssh_make_sessionid(ssh_session session) {
         goto error;
     }
 
-    if (session->next_crypto->kex_type == SSH_KEX_DH_GROUP1_SHA1 ||
-            session->next_crypto->kex_type == SSH_KEX_DH_GROUP14_SHA1) {
+    switch(session->next_crypto->kex_type) {
+    case SSH_KEX_DH_GROUP1_SHA1:
+    case SSH_KEX_DH_GROUP14_SHA1:
+    case SSH_KEX_DH_GROUP16_SHA512:
         rc = ssh_buffer_pack(buf,
                              "BB",
                              session->next_crypto->e,
@@ -606,11 +709,11 @@ int ssh_make_sessionid(ssh_session session) {
         if (rc != SSH_OK) {
             goto error;
         }
-
+        break;
 #ifdef HAVE_ECDH
-    } else if ((session->next_crypto->kex_type == SSH_KEX_ECDH_SHA2_NISTP256) ||
-               (session->next_crypto->kex_type == SSH_KEX_ECDH_SHA2_NISTP384) ||
-               (session->next_crypto->kex_type == SSH_KEX_ECDH_SHA2_NISTP521)) {
+    case SSH_KEX_ECDH_SHA2_NISTP256:
+    case SSH_KEX_ECDH_SHA2_NISTP384:
+    case SSH_KEX_ECDH_SHA2_NISTP521:
         if (session->next_crypto->ecdh_client_pubkey == NULL ||
             session->next_crypto->ecdh_server_pubkey == NULL) {
             SSH_LOG(SSH_LOG_WARNING, "ECDH parameted missing");
@@ -623,10 +726,11 @@ int ssh_make_sessionid(ssh_session session) {
         if (rc != SSH_OK) {
             goto error;
         }
+        break;
 #endif
 #ifdef HAVE_CURVE25519
-    } else if ((session->next_crypto->kex_type == SSH_KEX_CURVE25519_SHA256) ||
-               (session->next_crypto->kex_type == SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG)) {
+    case SSH_KEX_CURVE25519_SHA256:
+    case SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG:
         rc = ssh_buffer_pack(buf,
                              "dPdP",
                              CURVE25519_PUBKEY_SIZE,
@@ -637,6 +741,7 @@ int ssh_make_sessionid(ssh_session session) {
         if (rc != SSH_OK) {
             goto error;
         }
+        break;
 #endif
     }
     rc = ssh_buffer_pack(buf, "B", session->next_crypto->k);
@@ -661,6 +766,18 @@ int ssh_make_sessionid(ssh_session session) {
         sha1(ssh_buffer_get(buf), ssh_buffer_get_len(buf),
                                    session->next_crypto->secret_hash);
         break;
+    case SSH_KEX_DH_GROUP16_SHA512:
+        session->next_crypto->digest_len = SHA512_DIGEST_LENGTH;
+        session->next_crypto->mac_type = SSH_MAC_SHA512;
+        session->next_crypto->secret_hash = malloc(session->next_crypto->digest_len);
+        if (session->next_crypto->secret_hash == NULL) {
+            ssh_set_error_oom(session);
+            goto error;
+        }
+        sha512(ssh_buffer_get(buf),
+               ssh_buffer_get_len(buf),
+               session->next_crypto->secret_hash);
+        break;
     case SSH_KEX_ECDH_SHA2_NISTP256:
     case SSH_KEX_CURVE25519_SHA256:
     case SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG:
diff --git a/src/kex.c b/src/kex.c
index 04119907..25793ef6 100644
--- a/src/kex.c
+++ b/src/kex.c
@@ -98,7 +98,7 @@
 
 #define CHACHA20 "chacha20-poly1305@openssh.com,"
 
-#define KEY_EXCHANGE CURVE25519 ECDH "diffie-hellman-group14-sha1,diffie-hellman-group1-sha1"
+#define KEY_EXCHANGE CURVE25519 ECDH "diffie-hellman-group16-sha512,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1"
 #define KEX_METHODS_SIZE 10
 
 /* RFC 8308 */
@@ -755,6 +755,8 @@ int ssh_kex_select_methods (ssh_session session){
       session->next_crypto->kex_type=SSH_KEX_DH_GROUP1_SHA1;
     } else if(strcmp(session->next_crypto->kex_methods[SSH_KEX], "diffie-hellman-group14-sha1") == 0){
       session->next_crypto->kex_type=SSH_KEX_DH_GROUP14_SHA1;
+    } else if(strcmp(session->next_crypto->kex_methods[SSH_KEX], "diffie-hellman-group16-sha512") == 0){
+      session->next_crypto->kex_type=SSH_KEX_DH_GROUP16_SHA512;
     } else if(strcmp(session->next_crypto->kex_methods[SSH_KEX], "ecdh-sha2-nistp256") == 0){
       session->next_crypto->kex_type=SSH_KEX_ECDH_SHA2_NISTP256;
     } else if(strcmp(session->next_crypto->kex_methods[SSH_KEX], "ecdh-sha2-nistp384") == 0){
diff --git a/src/packet_cb.c b/src/packet_cb.c
index 6dfcbcab..eaad63d8 100644
--- a/src/packet_cb.c
+++ b/src/packet_cb.c
@@ -106,6 +106,7 @@ SSH_PACKET_CALLBACK(ssh_packet_dh_reply){
   switch(session->next_crypto->kex_type){
     case SSH_KEX_DH_GROUP1_SHA1:
     case SSH_KEX_DH_GROUP14_SHA1:
+    case SSH_KEX_DH_GROUP16_SHA512:
       rc=ssh_client_dh_reply(session, packet);
       break;
 #ifdef HAVE_ECDH
diff --git a/src/server.c b/src/server.c
index ff85d3a7..f98559a2 100644
--- a/src/server.c
+++ b/src/server.c
@@ -252,6 +252,7 @@ SSH_PACKET_CALLBACK(ssh_packet_kexdh_init){
   switch(session->next_crypto->kex_type){
       case SSH_KEX_DH_GROUP1_SHA1:
       case SSH_KEX_DH_GROUP14_SHA1:
+      case SSH_KEX_DH_GROUP16_SHA512:
         rc=ssh_server_kexdh_init(session, packet);
         break;
   #ifdef HAVE_ECDH
diff --git a/src/session.c b/src/session.c
index 28255221..d25c52cb 100644
--- a/src/session.c
+++ b/src/session.c
@@ -342,6 +342,8 @@ const char* ssh_get_kex_algo(ssh_session session) {
             return "diffie-hellman-group1-sha1";
         case SSH_KEX_DH_GROUP14_SHA1:
             return "diffie-hellman-group14-sha1";
+        case SSH_KEX_DH_GROUP16_SHA512:
+            return "diffie-hellman-group16-sha512";
         case SSH_KEX_ECDH_SHA2_NISTP256:
             return "ecdh-sha2-nistp256";
         case SSH_KEX_ECDH_SHA2_NISTP384:
diff --git a/tests/pkd/pkd_hello.c b/tests/pkd/pkd_hello.c
index 131883a1..3c727507 100644
--- a/tests/pkd/pkd_hello.c
+++ b/tests/pkd/pkd_hello.c
@@ -222,6 +222,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, rsa_ecdh_sha2_nistp256,                 kexcmd("ecdh-sha2-nistp256"),            setup_rsa,        teardown) \
     f(client, rsa_ecdh_sha2_nistp384,                 kexcmd("ecdh-sha2-nistp384"),            setup_rsa,        teardown) \
     f(client, rsa_ecdh_sha2_nistp521,                 kexcmd("ecdh-sha2-nistp521"),            setup_rsa,        teardown) \
+    f(client, rsa_diffie_hellman_group16_sha512,      kexcmd("diffie-hellman-group16-sha512"), setup_rsa,        teardown) \
     f(client, rsa_diffie_hellman_group14_sha1,        kexcmd("diffie-hellman-group14-sha1"),   setup_rsa,        teardown) \
     f(client, rsa_diffie_hellman_group1_sha1,         kexcmd("diffie-hellman-group1-sha1"),    setup_rsa,        teardown) \
     f(client, dsa_curve25519_sha256,                  kexcmd("curve25519-sha256"),             setup_dsa,        teardown) \
@@ -229,6 +230,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, dsa_ecdh_sha2_nistp256,                 kexcmd("ecdh-sha2-nistp256 "),           setup_dsa,        teardown) \
     f(client, dsa_ecdh_sha2_nistp384,                 kexcmd("ecdh-sha2-nistp384 "),           setup_dsa,        teardown) \
     f(client, dsa_ecdh_sha2_nistp521,                 kexcmd("ecdh-sha2-nistp521 "),           setup_dsa,        teardown) \
+    f(client, dsa_diffie_hellman_group16_sha512,      kexcmd("diffie-hellman-group16-sha512"), setup_dsa,        teardown) \
     f(client, dsa_diffie_hellman_group14_sha1,        kexcmd("diffie-hellman-group14-sha1"),   setup_dsa,        teardown) \
     f(client, dsa_diffie_hellman_group1_sha1,         kexcmd("diffie-hellman-group1-sha1"),    setup_dsa,        teardown) \
     f(client, ecdsa_256_curve25519_sha256,            kexcmd("curve25519-sha256"),             setup_ecdsa_256,  teardown) \
@@ -236,6 +238,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ecdsa_256_ecdh_sha2_nistp256,           kexcmd("ecdh-sha2-nistp256"),            setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_ecdh_sha2_nistp384,           kexcmd("ecdh-sha2-nistp384"),            setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_ecdh_sha2_nistp521,           kexcmd("ecdh-sha2-nistp521"),            setup_ecdsa_256,  teardown) \
+    f(client, ecdsa_256_diffie_hellman_group16_sha512,kexcmd("diffie-hellman-group16-sha512"), setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_diffie_hellman_group14_sha1,  kexcmd("diffie-hellman-group14-sha1"),   setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_diffie_hellman_group1_sha1,   kexcmd("diffie-hellman-group1-sha1"),    setup_ecdsa_256,  teardown) \
     f(client, ecdsa_384_curve25519_sha256,            kexcmd("curve25519-sha256"),             setup_ecdsa_384,  teardown) \
@@ -243,6 +246,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ecdsa_384_ecdh_sha2_nistp256,           kexcmd("ecdh-sha2-nistp256"),            setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_ecdh_sha2_nistp384,           kexcmd("ecdh-sha2-nistp384"),            setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_ecdh_sha2_nistp521,           kexcmd("ecdh-sha2-nistp521"),            setup_ecdsa_384,  teardown) \
+    f(client, ecdsa_384_diffie_hellman_group16_sha512,kexcmd("diffie-hellman-group16-sha512"), setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_diffie_hellman_group14_sha1,  kexcmd("diffie-hellman-group14-sha1"),   setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_diffie_hellman_group1_sha1,   kexcmd("diffie-hellman-group1-sha1"),    setup_ecdsa_384,  teardown) \
     f(client, ecdsa_521_curve25519_sha256,            kexcmd("curve25519-sha256"),             setup_ecdsa_521,  teardown) \
@@ -250,6 +254,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ecdsa_521_ecdh_sha2_nistp256,           kexcmd("ecdh-sha2-nistp256"),            setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_ecdh_sha2_nistp384,           kexcmd("ecdh-sha2-nistp384"),            setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_ecdh_sha2_nistp521,           kexcmd("ecdh-sha2-nistp521"),            setup_ecdsa_521,  teardown) \
+    f(client, ecdsa_521_diffie_hellman_group16_sha512,kexcmd("diffie-hellman-group16-sha512"), setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_diffie_hellman_group14_sha1,  kexcmd("diffie-hellman-group14-sha1"),   setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_diffie_hellman_group1_sha1,   kexcmd("diffie-hellman-group1-sha1"),    setup_ecdsa_521,  teardown)
 #else
@@ -260,6 +265,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, rsa_ecdh_sha2_nistp256,                 kexcmd("ecdh-sha2-nistp256"),            setup_rsa,        teardown) \
     f(client, rsa_ecdh_sha2_nistp384,                 kexcmd("ecdh-sha2-nistp384"),            setup_rsa,        teardown) \
     f(client, rsa_ecdh_sha2_nistp521,                 kexcmd("ecdh-sha2-nistp521"),            setup_rsa,        teardown) \
+    f(client, rsa_diffie_hellman_group16_sha512,      kexcmd("diffie-hellman-group16-sha512"), setup_rsa,        teardown) \
     f(client, rsa_diffie_hellman_group14_sha1,        kexcmd("diffie-hellman-group14-sha1"),   setup_rsa,        teardown) \
     f(client, rsa_diffie_hellman_group1_sha1,         kexcmd("diffie-hellman-group1-sha1"),    setup_rsa,        teardown) \
     f(client, ecdsa_256_curve25519_sha256,            kexcmd("curve25519-sha256"),             setup_ecdsa_256,  teardown) \
@@ -267,6 +273,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ecdsa_256_ecdh_sha2_nistp256,           kexcmd("ecdh-sha2-nistp256"),            setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_ecdh_sha2_nistp384,           kexcmd("ecdh-sha2-nistp384"),            setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_ecdh_sha2_nistp521,           kexcmd("ecdh-sha2-nistp521"),            setup_ecdsa_256,  teardown) \
+    f(client, ecdsa_256_diffie_hellman_group16_sha512,kexcmd("diffie-hellman-group16-sha512"), setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_diffie_hellman_group14_sha1,  kexcmd("diffie-hellman-group14-sha1"),   setup_ecdsa_256,  teardown) \
     f(client, ecdsa_256_diffie_hellman_group1_sha1,   kexcmd("diffie-hellman-group1-sha1"),    setup_ecdsa_256,  teardown) \
     f(client, ecdsa_384_curve25519_sha256,            kexcmd("curve25519-sha256"),             setup_ecdsa_384,  teardown) \
@@ -274,6 +281,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ecdsa_384_ecdh_sha2_nistp256,           kexcmd("ecdh-sha2-nistp256"),            setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_ecdh_sha2_nistp384,           kexcmd("ecdh-sha2-nistp384"),            setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_ecdh_sha2_nistp521,           kexcmd("ecdh-sha2-nistp521"),            setup_ecdsa_384,  teardown) \
+    f(client, ecdsa_384_diffie_hellman_group16_sha512,kexcmd("diffie-hellman-group16-sha512"), setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_diffie_hellman_group14_sha1,  kexcmd("diffie-hellman-group14-sha1"),   setup_ecdsa_384,  teardown) \
     f(client, ecdsa_384_diffie_hellman_group1_sha1,   kexcmd("diffie-hellman-group1-sha1"),    setup_ecdsa_384,  teardown) \
     f(client, ecdsa_521_curve25519_sha256,            kexcmd("curve25519-sha256"),             setup_ecdsa_521,  teardown) \
@@ -281,6 +289,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ecdsa_521_ecdh_sha2_nistp256,           kexcmd("ecdh-sha2-nistp256"),            setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_ecdh_sha2_nistp384,           kexcmd("ecdh-sha2-nistp384"),            setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_ecdh_sha2_nistp521,           kexcmd("ecdh-sha2-nistp521"),            setup_ecdsa_521,  teardown) \
+    f(client, ecdsa_521_diffie_hellman_group16_sha512,kexcmd("diffie-hellman-group16-sha512"), setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_diffie_hellman_group14_sha1,  kexcmd("diffie-hellman-group14-sha1"),   setup_ecdsa_521,  teardown) \
     f(client, ecdsa_521_diffie_hellman_group1_sha1,   kexcmd("diffie-hellman-group1-sha1"),    setup_ecdsa_521,  teardown)
 #endif
@@ -294,6 +303,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ed25519_ecdh_sha2_nistp256,             kexcmd("ecdh-sha2-nistp256"),            setup_ed25519,    teardown) \
     f(client, ed25519_ecdh_sha2_nistp384,             kexcmd("ecdh-sha2-nistp384"),            setup_ed25519,    teardown) \
     f(client, ed25519_ecdh_sha2_nistp521,             kexcmd("ecdh-sha2-nistp521"),            setup_ed25519,    teardown) \
+    f(client, ed25519_diffie_hellman_group16_sha512,  kexcmd("diffie-hellman-group16-sha512"), setup_ed25519,    teardown) \
     f(client, ed25519_diffie_hellman_group14_sha1,    kexcmd("diffie-hellman-group14-sha1"),   setup_ed25519,    teardown) \
     f(client, ed25519_diffie_hellman_group1_sha1,     kexcmd("diffie-hellman-group1-sha1"),    setup_ed25519,    teardown)
 #else
@@ -304,7 +314,7 @@ static int torture_pkd_setup_ecdsa_521(void **state) {
     f(client, ed25519_ecdh_sha2_nistp256,             kexcmd("ecdh-sha2-nistp256"),            setup_ed25519,    teardown) \
     f(client, ed25519_ecdh_sha2_nistp384,             kexcmd("ecdh-sha2-nistp384"),            setup_ed25519,    teardown) \
     f(client, ed25519_ecdh_sha2_nistp521,             kexcmd("ecdh-sha2-nistp521"),            setup_ed25519,    teardown) \
-    f(client, ed25519_diffie_hellman_group14_sha1,    kexcmd("diffie-hellman-group14-sha1"),   setup_ed25519,    teardown) \
+    f(client, ed25519_diffie_hellman_group16_sha512,  kexcmd("diffie-hellman-group16-sha512"), setup_ed25519,    teardown) \
     f(client, ed25519_diffie_hellman_group1_sha1,     kexcmd("diffie-hellman-group1-sha1"),    setup_ed25519,    teardown)
 #endif
 
diff --git a/tests/torture.c b/tests/torture.c
index 23b1d1fd..3fe4402f 100644
--- a/tests/torture.c
+++ b/tests/torture.c
@@ -603,6 +603,7 @@ static void torture_setup_create_sshd_config(void **state)
                            "ecdh-sha2-nistp384,ecdh-sha2-nistp521,"
                            "diffie-hellman-group-exchange-sha256,"
                            "diffie-hellman-group-exchange-sha1,"
+                           "diffie-hellman-group16-sha512,"
                            "diffie-hellman-group14-sha1,"
                            "diffie-hellman-group1-sha1\n"
 #endif /* OPENSSH_VERSION >= 6.7 */
diff --git a/tests/unittests/torture_config.c b/tests/unittests/torture_config.c
index 56c42093..e61ea99c 100644
--- a/tests/unittests/torture_config.c
+++ b/tests/unittests/torture_config.c
@@ -23,7 +23,7 @@ extern LIBSSH_THREAD int ssh_log_level;
 #define USERNAME "testuser"
 #define PROXYCMD "ssh -q -W %h:%p gateway.example.com"
 #define ID_FILE "/etc/xxx"
-#define KEXALGORITHMS "ecdh-sha2-nistp521,diffie-hellman-group14-sha1"
+#define KEXALGORITHMS "ecdh-sha2-nistp521,diffie-hellman-group16-sha512,diffie-hellman-group14-sha1"
 #define HOSTKEYALGORITHMS "ssh-ed25519,ecdsa-sha2-nistp521,ssh-rsa"
 #define PUBKEYACCEPTEDTYPES "rsa-sha2-512,ssh-rsa,ecdsa-sha2-nistp521"
 #define MACS "hmac-sha1,hmac-sha2-256"
diff --git a/tests/unittests/torture_options.c b/tests/unittests/torture_options.c
index 0053cf1b..f206919a 100644
--- a/tests/unittests/torture_options.c
+++ b/tests/unittests/torture_options.c
@@ -76,18 +76,18 @@ static void torture_options_set_key_exchange(void **state)
     /* Test known kexes */
     rc = ssh_options_set(session,
                          SSH_OPTIONS_KEY_EXCHANGE,
-                         "curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,diffie-hellman-group14-sha1");
+                         "curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,diffie-hellman-group16-sha512,diffie-hellman-group14-sha1");
     assert_true(rc == 0);
     assert_string_equal(session->opts.wanted_methods[SSH_KEX],
-                        "curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,diffie-hellman-group14-sha1");
+                        "curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,diffie-hellman-group16-sha512,diffie-hellman-group14-sha1");
 
     /* Test one unknown kex */
     rc = ssh_options_set(session,
                          SSH_OPTIONS_KEY_EXCHANGE,
-                         "curve25519-sha256,curve25519-sha256@libssh.org,unknown-crap@example.com,diffie-hellman-group14-sha1");
+                         "curve25519-sha256,curve25519-sha256@libssh.org,unknown-crap@example.com,diffie-hellman-group16-sha512,diffie-hellman-group14-sha1");
     assert_true(rc == 0);
     assert_string_equal(session->opts.wanted_methods[SSH_KEX],
-                        "curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group14-sha1");
+                        "curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group16-sha512,diffie-hellman-group14-sha1");
 
     /* Test all unknown kexes */
     rc = ssh_options_set(session,