112 lines
3.6 KiB
C
112 lines
3.6 KiB
C
/*
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luksrku - Tool to remotely unlock LUKS disks using TLS.
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Copyright (C) 2016-2016 Johannes Bauer
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This file is part of luksrku.
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luksrku is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; this program is ONLY licensed under
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version 3 of the License, later versions are explicitly excluded.
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luksrku is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with luksrku; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Johannes Bauer <JohannesBauer@gmx.de>
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*/
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#include <stdbool.h>
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#include <string.h>
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#include <openssl/evp.h>
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#include <openssl/ssl.h>
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#include <openssl/err.h>
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#include "openssl.h"
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#include "log.h"
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bool openssl_init(void) {
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OpenSSL_add_all_algorithms();
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ERR_load_ERR_strings();
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ERR_load_SSL_strings();
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return true;
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}
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bool create_generic_tls_context(struct generic_tls_ctx_t *gctx, bool server) {
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memset(gctx, 0, sizeof(struct generic_tls_ctx_t));
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gctx->conf_ctx = SSL_CONF_CTX_new();
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if (!gctx->conf_ctx) {
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log_openssl(LLVL_FATAL, "Cannot initialize TLS generic context config context.");
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return false;
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}
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if (server) {
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gctx->method = TLS_server_method();
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if (!gctx->method) {
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log_openssl(LLVL_FATAL, "Cannot initialize TLS server method.");
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return false;
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}
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} else {
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gctx->method = TLS_client_method();
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if (!gctx->method) {
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log_openssl(LLVL_FATAL, "Cannot initialize TLS client method.");
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return false;
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}
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}
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gctx->ctx = SSL_CTX_new(gctx->method);
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if (!gctx->ctx) {
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log_openssl(LLVL_FATAL, "Cannot initialize TLS generic context context.");
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return false;
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}
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/* Disable insecure previous protocol variants */
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/* Disable compression (not secure, should be disabled everywhere) */
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/* Disable DH param reuse (we use ECDH and this doesn't affect us, but in case someone changes to EDH) */
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/* Disable session resumption (unnecessary attack surface) */
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/* Disable resumption on renegotiation (unnecessary attack surface) */
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/* TODO: Disable renegotiation altogether! How? */
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const long flags = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1 | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_COMPRESSION | SSL_OP_SINGLE_DH_USE | SSL_OP_NO_TICKET | SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION;
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SSL_CTX_set_options(gctx->ctx, flags);
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if (!SSL_CTX_set_min_proto_version(gctx->ctx, TLS1_2_VERSION)) {
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log_openssl(LLVL_FATAL, "Cannot set TLS generic context minimal version.");
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return false;
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}
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if (!SSL_CTX_set_cipher_list(gctx->ctx, "ECDHE-PSK-CHACHA20-POLY1305")) {
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log_openssl(LLVL_FATAL, "Cannot set TLS generic context cipher suites.");
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return false;
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}
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/* In the cipher suite we're using, none of these should be used anyways
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* (PSK); however for the future we want to have proper crypto here as
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* well. */
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if (!SSL_CTX_set1_sigalgs_list(gctx->ctx, "ECDSA+SHA256:RSA+SHA256:ECDSA+SHA384:RSA+SHA384:ECDSA+SHA512:RSA+SHA512")) {
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log_openssl(LLVL_FATAL, "Cannot set TLS generic context signature algorithms.");
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return false;
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}
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/* TODO: When X448 becomes available, include it here. */
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if (!SSL_CTX_set1_curves_list(gctx->ctx, "X25519")) {
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log_openssl(LLVL_FATAL, "Cannot set TLS generic context ECDHE curves.");
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return false;
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}
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return true;
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}
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void free_generic_tls_context(struct generic_tls_ctx_t *gctx) {
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SSL_CTX_free(gctx->ctx);
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gctx->ctx = NULL;
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SSL_CONF_CTX_free(gctx->conf_ctx);
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gctx->conf_ctx = NULL;
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}
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