/*************************************************************************/ /* stream_peer_openssl.cpp */ /*************************************************************************/ /* This file is part of: */ /* GODOT ENGINE */ /* http://www.godotengine.org */ /*************************************************************************/ /* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */ /* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */ /* */ /* Permission is hereby granted, free of charge, to any person obtaining */ /* a copy of this software and associated documentation files (the */ /* "Software"), to deal in the Software without restriction, including */ /* without limitation the rights to use, copy, modify, merge, publish, */ /* distribute, sublicense, and/or sell copies of the Software, and to */ /* permit persons to whom the Software is furnished to do so, subject to */ /* the following conditions: */ /* */ /* The above copyright notice and this permission notice shall be */ /* included in all copies or substantial portions of the Software. */ /* */ /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /*************************************************************************/ #include "stream_peer_openssl.h" //hostname matching code from curl //#include // To prevent crashing (see the OpenSSL FAQ) bool StreamPeerOpenSSL::_match_host_name(const char *name, const char *hostname) { return Tool_Curl_cert_hostcheck(name, hostname) == CURL_HOST_MATCH; // print_line("MATCH: "+String(name)+" vs "+String(hostname)); // return true; } Error StreamPeerOpenSSL::_match_common_name(const char *hostname, const X509 *server_cert) { int common_name_loc = -1; X509_NAME_ENTRY *common_name_entry = NULL; ASN1_STRING *common_name_asn1 = NULL; char *common_name_str = NULL; // Find the position of the CN field in the Subject field of the certificate common_name_loc = X509_NAME_get_index_by_NID(X509_get_subject_name((X509 *)server_cert), NID_commonName, -1); ERR_FAIL_COND_V(common_name_loc < 0, ERR_INVALID_PARAMETER); // Extract the CN field common_name_entry = X509_NAME_get_entry(X509_get_subject_name((X509 *)server_cert), common_name_loc); ERR_FAIL_COND_V(common_name_entry == NULL, ERR_INVALID_PARAMETER); // Convert the CN field to a C string common_name_asn1 = X509_NAME_ENTRY_get_data(common_name_entry); ERR_FAIL_COND_V(common_name_asn1 == NULL, ERR_INVALID_PARAMETER); common_name_str = (char *)ASN1_STRING_data(common_name_asn1); // Make sure there isn't an embedded NUL character in the CN bool malformed_certificate = (size_t)ASN1_STRING_length(common_name_asn1) != strlen(common_name_str); ERR_FAIL_COND_V(malformed_certificate, ERR_INVALID_PARAMETER); // Compare expected hostname with the CN return _match_host_name(common_name_str, hostname) ? OK : FAILED; } /** * Tries to find a match for hostname in the certificate's Subject Alternative Name extension. * */ Error StreamPeerOpenSSL::_match_subject_alternative_name(const char *hostname, const X509 *server_cert) { Error result = FAILED; int i; int san_names_nb = -1; STACK_OF(GENERAL_NAME) *san_names = NULL; // Try to extract the names within the SAN extension from the certificate san_names = (STACK_OF(GENERAL_NAME) *)X509_get_ext_d2i((X509 *)server_cert, NID_subject_alt_name, NULL, NULL); if (san_names == NULL) { return ERR_FILE_NOT_FOUND; } san_names_nb = sk_GENERAL_NAME_num(san_names); // Check each name within the extension for (i = 0; i < san_names_nb; i++) { const GENERAL_NAME *current_name = sk_GENERAL_NAME_value(san_names, i); if (current_name->type == GEN_DNS) { // Current name is a DNS name, let's check it char *dns_name = (char *)ASN1_STRING_data(current_name->d.dNSName); // Make sure there isn't an embedded NUL character in the DNS name if ((size_t)ASN1_STRING_length(current_name->d.dNSName) != strlen(dns_name)) { result = ERR_INVALID_PARAMETER; break; } else { // Compare expected hostname with the DNS name if (_match_host_name(dns_name, hostname)) { result = OK; break; } } } } sk_GENERAL_NAME_pop_free(san_names, GENERAL_NAME_free); return result; } /* See http://archives.seul.org/libevent/users/Jan-2013/msg00039.html */ int StreamPeerOpenSSL::_cert_verify_callback(X509_STORE_CTX *x509_ctx, void *arg) { /* This is the function that OpenSSL would call if we hadn't called * SSL_CTX_set_cert_verify_callback(). Therefore, we are "wrapping" * the default functionality, rather than replacing it. */ bool base_cert_valid = X509_verify_cert(x509_ctx); if (!base_cert_valid) { print_line("Cause: " + String(X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509_ctx)))); ERR_print_errors_fp(stdout); } X509 *server_cert = X509_STORE_CTX_get_current_cert(x509_ctx); ERR_FAIL_COND_V(!server_cert, 0); char cert_str[256]; X509_NAME_oneline(X509_get_subject_name(server_cert), cert_str, sizeof(cert_str)); print_line("CERT STR: " + String(cert_str)); print_line("VALID: " + itos(base_cert_valid)); if (!base_cert_valid) return 0; StreamPeerOpenSSL *ssl = (StreamPeerOpenSSL *)arg; if (ssl->validate_hostname) { Error err = _match_subject_alternative_name(ssl->hostname.utf8().get_data(), server_cert); if (err == ERR_FILE_NOT_FOUND) { err = _match_common_name(ssl->hostname.utf8().get_data(), server_cert); } if (err != OK) { ssl->status = STATUS_ERROR_HOSTNAME_MISMATCH; return 0; } } return 1; } int StreamPeerOpenSSL::_bio_create(BIO *b) { b->init = 1; b->num = 0; b->ptr = NULL; b->flags = 0; return 1; } int StreamPeerOpenSSL::_bio_destroy(BIO *b) { if (b == NULL) return 0; b->ptr = NULL; /* sb_tls_remove() will free it */ b->init = 0; b->flags = 0; return 1; } int StreamPeerOpenSSL::_bio_read(BIO *b, char *buf, int len) { if (buf == NULL || len <= 0) return 0; StreamPeerOpenSSL *sp = (StreamPeerOpenSSL *)b->ptr; ERR_FAIL_COND_V(sp == NULL, 0); BIO_clear_retry_flags(b); if (sp->use_blocking) { Error err = sp->base->get_data((uint8_t *)buf, len); if (err != OK) { return -1; } return len; } else { int got; Error err = sp->base->get_partial_data((uint8_t *)buf, len, got); if (err != OK) { return -1; } if (got == 0) { BIO_set_retry_read(b); } return got; } //unreachable return 0; } int StreamPeerOpenSSL::_bio_write(BIO *b, const char *buf, int len) { if (buf == NULL || len <= 0) return 0; StreamPeerOpenSSL *sp = (StreamPeerOpenSSL *)b->ptr; ERR_FAIL_COND_V(sp == NULL, 0); BIO_clear_retry_flags(b); if (sp->use_blocking) { Error err = sp->base->put_data((const uint8_t *)buf, len); if (err != OK) { return -1; } return len; } else { int sent; Error err = sp->base->put_partial_data((const uint8_t *)buf, len, sent); if (err != OK) { return -1; } if (sent == 0) { BIO_set_retry_write(b); } return sent; } //unreachable return 0; } long StreamPeerOpenSSL::_bio_ctrl(BIO *b, int cmd, long num, void *ptr) { if (cmd == BIO_CTRL_FLUSH) { /* The OpenSSL library needs this */ return 1; } return 0; } int StreamPeerOpenSSL::_bio_gets(BIO *b, char *buf, int len) { return -1; } int StreamPeerOpenSSL::_bio_puts(BIO *b, const char *str) { return _bio_write(b, str, strlen(str)); } BIO_METHOD StreamPeerOpenSSL::_bio_method = { /* it's a source/sink BIO */ (100 | 0x400), "streampeer glue", _bio_write, _bio_read, _bio_puts, _bio_gets, _bio_ctrl, _bio_create, _bio_destroy }; Error StreamPeerOpenSSL::connect(Ref p_base, bool p_validate_certs, const String &p_for_hostname) { if (connected) disconnect(); hostname = p_for_hostname; status = STATUS_DISCONNECTED; // Set up a SSL_CTX object, which will tell our BIO object how to do its work ctx = SSL_CTX_new(SSLv23_client_method()); base = p_base; validate_certs = p_validate_certs; validate_hostname = p_for_hostname != ""; if (p_validate_certs) { if (certs.size()) { //yay for undocumented OpenSSL functions X509_STORE *store = SSL_CTX_get_cert_store(ctx); for (int i = 0; i < certs.size(); i++) { X509_STORE_add_cert(store, certs[i]); } #if 0 const unsigned char *in=(const unsigned char *)certs.ptr(); X509 *Cert = d2i_X509(NULL, &in, certs.size()-1); if (!Cert) { print_line(String(ERR_error_string(ERR_get_error(),NULL))); } ERR_FAIL_COND_V(!Cert,ERR_PARSE_ERROR); X509_STORE *store = SSL_CTX_get_cert_store(ctx); X509_STORE_add_cert(store,Cert); //char *str = X509_NAME_oneline(X509_get_subject_name(Cert),0,0); //printf ("subject: %s\n", str); /* [1] */ #endif } //used for testing //int res = SSL_CTX_load_verify_locations(ctx,"/etc/ssl/certs/ca-certificates.crt",NULL); //print_line("verify locations res: "+itos(res)); /* Ask OpenSSL to verify the server certificate. Note that this * does NOT include verifying that the hostname is correct. * So, by itself, this means anyone with any legitimate * CA-issued certificate for any website, can impersonate any * other website in the world. This is not good. See "The * Most Dangerous Code in the World" article at * https://crypto.stanford.edu/~dabo/pubs/abstracts/ssl-client-bugs.html */ SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL); /* This is how we solve the problem mentioned in the previous * comment. We "wrap" OpenSSL's validation routine in our * own routine, which also validates the hostname by calling * the code provided by iSECPartners. Note that even though * the "Everything You've Always Wanted to Know About * Certificate Validation With OpenSSL (But Were Afraid to * Ask)" paper from iSECPartners says very explicitly not to * call SSL_CTX_set_cert_verify_callback (at the bottom of * page 2), what we're doing here is safe because our * cert_verify_callback() calls X509_verify_cert(), which is * OpenSSL's built-in routine which would have been called if * we hadn't set the callback. Therefore, we're just * "wrapping" OpenSSL's routine, not replacing it. */ SSL_CTX_set_cert_verify_callback(ctx, _cert_verify_callback, this); //Let the verify_callback catch the verify_depth error so that we get an appropriate error in the logfile. (??) SSL_CTX_set_verify_depth(ctx, max_cert_chain_depth + 1); } ssl = SSL_new(ctx); bio = BIO_new(&_bio_method); bio->ptr = this; SSL_set_bio(ssl, bio, bio); if (p_for_hostname != String()) { SSL_set_tlsext_host_name(ssl, p_for_hostname.utf8().get_data()); } use_blocking = true; // let handshake use blocking // Set the SSL to automatically retry on failure. SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY); // Same as before, try to connect. int result = SSL_connect(ssl); print_line("CONNECTION RESULT: " + itos(result)); if (result < 1) { ERR_print_errors_fp(stdout); _print_error(result); } X509 *peer = SSL_get_peer_certificate(ssl); if (peer) { bool cert_ok = SSL_get_verify_result(ssl) == X509_V_OK; print_line("cert_ok: " + itos(cert_ok)); } else if (validate_certs) { status = STATUS_ERROR_NO_CERTIFICATE; } connected = true; status = STATUS_CONNECTED; return OK; } Error StreamPeerOpenSSL::accept(Ref p_base) { return ERR_UNAVAILABLE; } void StreamPeerOpenSSL::_print_error(int err) { err = SSL_get_error(ssl, err); switch (err) { case SSL_ERROR_NONE: ERR_PRINT("NO ERROR: The TLS/SSL I/O operation completed"); break; case SSL_ERROR_ZERO_RETURN: ERR_PRINT("The TLS/SSL connection has been closed."); case SSL_ERROR_WANT_READ: case SSL_ERROR_WANT_WRITE: ERR_PRINT("The operation did not complete."); break; case SSL_ERROR_WANT_CONNECT: case SSL_ERROR_WANT_ACCEPT: ERR_PRINT("The connect/accept operation did not complete"); break; case SSL_ERROR_WANT_X509_LOOKUP: ERR_PRINT("The operation did not complete because an application callback set by SSL_CTX_set_client_cert_cb() has asked to be called again."); break; case SSL_ERROR_SYSCALL: ERR_PRINT("Some I/O error occurred. The OpenSSL error queue may contain more information on the error."); break; case SSL_ERROR_SSL: ERR_PRINT("A failure in the SSL library occurred, usually a protocol error."); break; } } Error StreamPeerOpenSSL::put_data(const uint8_t *p_data, int p_bytes) { ERR_FAIL_COND_V(!connected, ERR_UNCONFIGURED); while (p_bytes > 0) { int ret = SSL_write(ssl, p_data, p_bytes); if (ret <= 0) { _print_error(ret); disconnect(); return ERR_CONNECTION_ERROR; } p_data += ret; p_bytes -= ret; } return OK; } Error StreamPeerOpenSSL::put_partial_data(const uint8_t *p_data, int p_bytes, int &r_sent) { ERR_FAIL_COND_V(!connected, ERR_UNCONFIGURED); if (p_bytes == 0) return OK; Error err = put_data(p_data, p_bytes); if (err != OK) return err; r_sent = p_bytes; return OK; } Error StreamPeerOpenSSL::get_data(uint8_t *p_buffer, int p_bytes) { ERR_FAIL_COND_V(!connected, ERR_UNCONFIGURED); while (p_bytes > 0) { int ret = SSL_read(ssl, p_buffer, p_bytes); if (ret <= 0) { _print_error(ret); disconnect(); return ERR_CONNECTION_ERROR; } p_buffer += ret; p_bytes -= ret; } return OK; } Error StreamPeerOpenSSL::get_partial_data(uint8_t *p_buffer, int p_bytes, int &r_received) { ERR_FAIL_COND_V(!connected, ERR_UNCONFIGURED); if (p_bytes == 0) { r_received = 0; return OK; } Error err = get_data(p_buffer, p_bytes); if (err != OK) return err; r_received = p_bytes; return OK; } int StreamPeerOpenSSL::get_available_bytes() const { ERR_FAIL_COND_V(!connected, 0); return SSL_pending(ssl); } StreamPeerOpenSSL::StreamPeerOpenSSL() { ctx = NULL; ssl = NULL; bio = NULL; connected = false; use_blocking = true; //might be improved int the future, but for now it always blocks max_cert_chain_depth = 9; flags = 0; } void StreamPeerOpenSSL::disconnect() { if (!connected) return; SSL_shutdown(ssl); SSL_free(ssl); SSL_CTX_free(ctx); base = Ref(); connected = false; validate_certs = false; validate_hostname = false; status = STATUS_DISCONNECTED; } StreamPeerOpenSSL::Status StreamPeerOpenSSL::get_status() const { return status; } StreamPeerOpenSSL::~StreamPeerOpenSSL() { disconnect(); } StreamPeerSSL *StreamPeerOpenSSL::_create_func() { return memnew(StreamPeerOpenSSL); } Vector StreamPeerOpenSSL::certs; void StreamPeerOpenSSL::_load_certs(const ByteArray &p_array) { ByteArray::Read r = p_array.read(); BIO *mem = BIO_new(BIO_s_mem()); BIO_puts(mem, (const char *)r.ptr()); while (true) { X509 *cert = PEM_read_bio_X509(mem, NULL, 0, NULL); if (!cert) break; certs.push_back(cert); } BIO_free(mem); } void StreamPeerOpenSSL::initialize_ssl() { available = true; load_certs_func = _load_certs; _create = _create_func; CRYPTO_malloc_init(); // Initialize malloc, free, etc for OpenSSL's use SSL_library_init(); // Initialize OpenSSL's SSL libraries SSL_load_error_strings(); // Load SSL error strings ERR_load_BIO_strings(); // Load BIO error strings OpenSSL_add_all_algorithms(); // Load all available encryption algorithms String certs_path = GLOBAL_DEF("ssl/certificates", ""); Globals::get_singleton()->set_custom_property_info("ssl/certificates", PropertyInfo(Variant::STRING, "ssl/certificates", PROPERTY_HINT_FILE, "*.crt")); if (certs_path != "") { FileAccess *f = FileAccess::open(certs_path, FileAccess::READ); if (f) { ByteArray arr; int flen = f->get_len(); arr.resize(flen + 1); { ByteArray::Write w = arr.write(); f->get_buffer(w.ptr(), flen); w[flen] = 0; //end f string } memdelete(f); _load_certs(arr); print_line("Loaded certs from '" + certs_path + "': " + itos(certs.size())); } } String config_path = GLOBAL_DEF("ssl/config", ""); Globals::get_singleton()->set_custom_property_info("ssl/config", PropertyInfo(Variant::STRING, "ssl/config", PROPERTY_HINT_FILE, "*.cnf")); if (config_path != "") { Vector data = FileAccess::get_file_as_array(config_path); if (data.size()) { data.push_back(0); BIO *mem = BIO_new(BIO_s_mem()); BIO_puts(mem, (const char *)data.ptr()); while (true) { X509 *cert = PEM_read_bio_X509(mem, NULL, 0, NULL); if (!cert) break; certs.push_back(cert); } BIO_free(mem); } print_line("Loaded certs from '" + certs_path + "': " + itos(certs.size())); } } void StreamPeerOpenSSL::finalize_ssl() { for (int i = 0; i < certs.size(); i++) { X509_free(certs[i]); } certs.clear(); }