319 lines
6.5 KiB
C
319 lines
6.5 KiB
C
/**
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* FreeRDP: A Remote Desktop Protocol Client
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* Transport Layer Security
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*
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* Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <freerdp/utils/stream.h>
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#include <freerdp/utils/memory.h>
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#include "tls.h"
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boolean tls_connect(rdpTls* tls)
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{
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int connection_status;
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tls->ctx = SSL_CTX_new(TLSv1_client_method());
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if (tls->ctx == NULL)
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{
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printf("SSL_CTX_new failed\n");
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return False;
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}
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/*
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* This is necessary, because the Microsoft TLS implementation is not perfect.
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* SSL_OP_ALL enables a couple of workarounds for buggy TLS implementations,
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* but the most important workaround being SSL_OP_TLS_BLOCK_PADDING_BUG.
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* As the size of the encrypted payload may give hints about its contents,
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* block padding is normally used, but the Microsoft TLS implementation
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* won't recognize it and will disconnect you after sending a TLS alert.
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*/
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SSL_CTX_set_options(tls->ctx, SSL_OP_ALL);
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tls->ssl = SSL_new(tls->ctx);
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if (tls->ssl == NULL)
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{
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printf("SSL_new failed\n");
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return False;
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}
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if (SSL_set_fd(tls->ssl, tls->sockfd) < 1)
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{
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printf("SSL_set_fd failed\n");
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return False;
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}
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connection_status = SSL_connect(tls->ssl);
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if (connection_status <= 0)
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{
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if (tls_print_error("SSL_connect", tls->ssl, connection_status))
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return False;
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}
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return True;
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}
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boolean tls_accept(rdpTls* tls, const char* cert_file, const char* privatekey_file)
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{
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int connection_status;
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tls->ctx = SSL_CTX_new(TLSv1_server_method());
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if (tls->ctx == NULL)
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{
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printf("SSL_CTX_new failed\n");
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return False;
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}
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if (SSL_CTX_use_RSAPrivateKey_file(tls->ctx, privatekey_file, SSL_FILETYPE_PEM) <= 0)
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{
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printf("SSL_CTX_use_RSAPrivateKey_file failed\n");
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return False;
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}
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tls->ssl = SSL_new(tls->ctx);
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if (tls->ssl == NULL)
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{
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printf("SSL_new failed\n");
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return False;
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}
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if (SSL_use_certificate_file(tls->ssl, cert_file, SSL_FILETYPE_PEM) <= 0)
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{
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printf("SSL_use_certificate_file failed\n");
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return False;
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}
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if (SSL_set_fd(tls->ssl, tls->sockfd) < 1)
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{
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printf("SSL_set_fd failed\n");
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return False;
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}
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connection_status = SSL_accept(tls->ssl);
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if (connection_status <= 0)
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{
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if (tls_print_error("SSL_accept", tls->ssl, connection_status))
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return False;
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}
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printf("TLS connection accepted\n");
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return True;
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}
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boolean tls_disconnect(rdpTls* tls)
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{
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SSL_shutdown(tls->ssl);
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return True;
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}
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int tls_read(rdpTls* tls, uint8* data, int length)
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{
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int status;
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status = SSL_read(tls->ssl, data, length);
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switch (SSL_get_error(tls->ssl, status))
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{
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case SSL_ERROR_NONE:
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break;
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case SSL_ERROR_WANT_READ:
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case SSL_ERROR_WANT_WRITE:
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status = 0;
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break;
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default:
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tls_print_error("SSL_read", tls->ssl, status);
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status = -1;
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break;
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}
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return status;
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}
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int tls_write(rdpTls* tls, uint8* data, int length)
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{
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int status;
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status = SSL_write(tls->ssl, data, length);
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switch (SSL_get_error(tls->ssl, status))
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{
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case SSL_ERROR_NONE:
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break;
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case SSL_ERROR_WANT_READ:
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case SSL_ERROR_WANT_WRITE:
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status = 0;
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break;
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default:
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tls_print_error("SSL_write", tls->ssl, status);
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status = -1;
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break;
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}
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return status;
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}
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boolean tls_print_error(char *func, SSL *connection, int value)
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{
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switch (SSL_get_error(connection, value))
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{
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case SSL_ERROR_ZERO_RETURN:
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printf("%s: Server closed TLS connection\n", func);
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return True;
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case SSL_ERROR_WANT_READ:
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printf("SSL_ERROR_WANT_READ\n");
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return False;
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case SSL_ERROR_WANT_WRITE:
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printf("SSL_ERROR_WANT_WRITE\n");
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return False;
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case SSL_ERROR_SYSCALL:
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printf("%s: I/O error\n", func);
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return True;
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case SSL_ERROR_SSL:
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printf("%s: Failure in SSL library (protocol error?)\n", func);
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return True;
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default:
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printf("%s: Unknown error\n", func);
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return True;
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}
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}
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CryptoCert tls_get_certificate(rdpTls * tls)
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{
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CryptoCert cert;
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X509* server_cert;
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server_cert = SSL_get_peer_certificate(tls->ssl);
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if (!server_cert)
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{
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printf("ssl_verify: failed to get the server SSL certificate\n");
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cert = NULL;
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}
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else
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{
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cert = xmalloc(sizeof(*cert));
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cert->px509 = server_cert;
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}
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return cert;
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}
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rdpTls* tls_new()
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{
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rdpTls* tls;
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tls = (rdpTls*) xzalloc(sizeof(rdpTls));
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if (tls != NULL)
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{
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SSL_load_error_strings();
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SSL_library_init();
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}
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return tls;
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}
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int tls_verify_certificate(CryptoCert cert, rdpSettings* settings, char* hostname)
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{
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boolean status;
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rdpCertStore* certstore;
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status = x509_verify_cert(cert, settings);
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if (status != True)
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{
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rdpCertData* certdata;
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certdata = crypto_get_cert_data(cert->px509, hostname);
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certstore = certstore_new(certdata, settings->home_path);
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if (cert_data_match(certstore) == 0)
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goto end;
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if (certstore->match == 1)
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{
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boolean accept_certificate = settings->ignore_certificate;
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if(!accept_certificate)
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{
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char* issuer = crypto_cert_issuer(cert->px509);
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char* subject = crypto_cert_subject(cert->px509);
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char* fingerprint = crypto_cert_fingerprint(cert->px509);
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freerdp* instance = (freerdp*)settings->instance;
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if(instance->VerifyCertificate)
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accept_certificate = instance->VerifyCertificate(instance, subject, issuer, fingerprint);
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xfree(issuer);
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xfree(subject);
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xfree(fingerprint);
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}
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if(!accept_certificate)
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return 1;
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}
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else if (certstore->match == -1)
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{
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tls_print_cert_error();
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certstore_free(certstore);
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return 1;
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}
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end:
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certstore_free(certstore);
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}
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return 0;
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}
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void tls_print_cert_error()
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{
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printf("#####################################\n");
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printf("##############WARNING################\n");
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printf("#####################################\n");
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printf("The thumbprint of certificate received\n");
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printf("did not match the stored thumbprint.You\n");
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printf("might be a victim of MAN in the MIDDLE\n");
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printf("ATTACK.It is also possible that server's\n");
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printf("certificate have been changed.In that case\n");
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printf("contact your server administrator\n");
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}
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void tls_free(rdpTls* tls)
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{
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if (tls != NULL)
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{
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if (tls->ssl)
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SSL_free(tls->ssl);
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if (tls->ctx)
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SSL_CTX_free(tls->ctx);
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xfree(tls);
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}
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}
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