server: Add ecdsa hostkey support.

include/libssh/bind.h

@@ -34,8 +34,10 @@ struct ssh_bind_struct {
   /* options */
   char *wanted_methods[10];
   char *banner;
+  char *ecdsakey;
   char *dsakey;
   char *rsakey;
+  ssh_key ecdsa;
   ssh_key dsa;
   ssh_key rsa;
   char *bindaddr;

include/libssh/session.h

@@ -141,6 +141,7 @@ struct ssh_session_struct {
     struct {
         ssh_key rsa_key;
         ssh_key dsa_key;
+        ssh_key ecdsa_key;
 
         /* The type of host key wanted by client */
         enum ssh_keytypes_e hostkey;

src/bind.c

@@ -165,12 +165,36 @@ int ssh_bind_listen(ssh_bind sshbind) {
     return -1;
   }
 
-  if (sshbind->dsakey == NULL && sshbind->rsakey == NULL) {
+  if (sshbind->ecdsakey == NULL &&
+      sshbind->dsakey == NULL &&
+      sshbind->rsakey == NULL) {
       ssh_set_error(sshbind, SSH_FATAL,
               "DSA or RSA host key file must be set before listen()");
       return SSH_ERROR;
   }
 
+#ifdef HAVE_ECC
+  if (sshbind->ecdsakey) {
+      rc = ssh_pki_import_privkey_file(sshbind->ecdsakey,
+                                       NULL,
+                                       NULL,
+                                       NULL,
+                                       &sshbind->ecdsa);
+      if (rc == SSH_ERROR) {
+          ssh_set_error(sshbind, SSH_FATAL,
+                  "Failed to import private ECDSA host key");
+          return SSH_ERROR;
+      }
+
+      if (ssh_key_type(sshbind->ecdsa) != SSH_KEYTYPE_ECDSA) {
+          ssh_set_error(sshbind, SSH_FATAL,
+                  "The ECDSA host key has the wrong type");
+          ssh_key_free(sshbind->ecdsa);
+          return SSH_ERROR;
+      }
+  }
+#endif
+
   if (sshbind->dsakey) {
       rc = ssh_pki_import_privkey_file(sshbind->dsakey,
                                        NULL,
@@ -385,6 +409,15 @@ int ssh_bind_accept_fd(ssh_bind sshbind, ssh_session session, socket_t fd){
     ssh_socket_set_fd(session->socket, fd);
     ssh_socket_get_poll_handle_out(session->socket);
 
+#ifdef HAVE_ECC
+    if (sshbind->ecdsa) {
+        session->srv.ecdsa_key = ssh_key_dup(sshbind->ecdsa);
+        if (session->srv.ecdsa_key == NULL) {
+          ssh_set_error_oom(sshbind);
+          return SSH_ERROR;
+        }
+    }
+#endif
     if (sshbind->dsa) {
         session->srv.dsa_key = ssh_key_dup(sshbind->dsa);
         if (session->srv.dsa_key == NULL) {

src/server.c

@@ -84,24 +84,47 @@ static int dh_handshake_server(ssh_session session);
 
 static int server_set_kex(ssh_session session) {
   struct ssh_kex_struct *server = &session->next_crypto->server_kex;
-  int i, j;
+  int i, j, rc;
   const char *wanted;
+  char hostkeys[64] = {0};
+  enum ssh_keytypes_e keytype;
+  size_t len;
 
   ZERO_STRUCTP(server);
   ssh_get_random(server->cookie, 16, 0);
-  if (session->srv.dsa_key != NULL && session->srv.rsa_key != NULL) {
-    if (ssh_options_set_algo(session, SSH_HOSTKEYS,
-          "ssh-dss,ssh-rsa") < 0) {
+
+#ifdef HAVE_ECC
+  if (session->srv.ecdsa_key != NULL) {
+      keytype = ssh_key_type(session->srv.ecdsa_key);
+
+      snprintf(hostkeys, sizeof(hostkeys),
+               "%s", session->srv.ecdsa_key->type_c);
+  }
+#endif
+  if (session->srv.dsa_key != NULL) {
+      len = strlen(hostkeys);
+      keytype = ssh_key_type(session->srv.dsa_key);
+
+      snprintf(hostkeys + len, sizeof(hostkeys) - len,
+               ",%s", ssh_key_type_to_char(keytype));
+  }
+  if (session->srv.rsa_key != NULL) {
+      len = strlen(hostkeys);
+      keytype = ssh_key_type(session->srv.rsa_key);
+
+      snprintf(hostkeys + len, sizeof(hostkeys) - len,
+               ",%s", ssh_key_type_to_char(keytype));
+  }
+
+  if (strlen(hostkeys) == 0) {
       return -1;
-    }
-  } else if (session->srv.dsa_key != NULL) {
-    if (ssh_options_set_algo(session, SSH_HOSTKEYS, "ssh-dss") < 0) {
+  }
+
+  rc = ssh_options_set_algo(session,
+                            SSH_HOSTKEYS,
+                            hostkeys[0] == ',' ? hostkeys + 1 : hostkeys);
+  if (rc < 0) {
       return -1;
-    }
-  } else {
-    if (ssh_options_set_algo(session, SSH_HOSTKEYS, "ssh-rsa") < 0) {
-      return -1;
-    }
   }
 
   for (i = 0; i < 10; i++) {
@@ -186,6 +209,8 @@ int ssh_get_key_params(ssh_session session, ssh_key *privkey){
         *privkey = session->srv.rsa_key;
         break;
       case SSH_KEYTYPE_ECDSA:
+        *privkey = session->srv.ecdsa_key;
+        break;
       case SSH_KEYTYPE_UNKNOWN:
         *privkey = NULL;
     }
@@ -263,6 +288,12 @@ static int dh_handshake_server(ssh_session session) {
       ssh_key_free(session->srv.dsa_key);
       session->srv.dsa_key = NULL;
   }
+#ifdef HAVE_ECC
+  if (session->srv.ecdsa_key) {
+      ssh_key_free(session->srv.ecdsa_key);
+      session->srv.ecdsa_key = NULL;
+  }
+#endif
 
   if (buffer_add_u8(session->out_buffer, SSH2_MSG_KEXDH_REPLY) < 0 ||
       buffer_add_ssh_string(session->out_buffer,