/* * OpenVPN -- An application to securely tunnel IP networks * over a single TCP/UDP port, with support for SSL/TLS-based * session authentication and key exchange, * packet encryption, packet authentication, and * packet compression. * * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. * Copyright (C) 2010 Fox Crypto B.V. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program (see the file COPYING included with this * distribution); if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /** * @file Control Channel OpenSSL Backend */ #ifdef HAVE_CONFIG_H #include "config.h" #elif defined(_MSC_VER) #include "config-msvc.h" #endif #include "syshead.h" #if defined(ENABLE_CRYPTO) && defined(ENABLE_CRYPTO_OPENSSL) #include "errlevel.h" #include "buffer.h" #include "misc.h" #include "manage.h" #include "memdbg.h" #include "ssl_backend.h" #include "ssl_common.h" #include "base64.h" #ifdef ENABLE_CRYPTOAPI #include "cryptoapi.h" #endif #include "ssl_verify_openssl.h" #include #include #include #include #ifndef OPENSSL_NO_EC #include #endif /* * Allocate space in SSL objects in which to store a struct tls_session * pointer back to parent. * */ int mydata_index; /* GLOBAL */ void tls_init_lib() { SSL_library_init(); #ifndef ENABLE_SMALL SSL_load_error_strings(); #endif OpenSSL_add_all_algorithms (); mydata_index = SSL_get_ex_new_index(0, "struct session *", NULL, NULL, NULL); ASSERT (mydata_index >= 0); } void tls_free_lib() { EVP_cleanup(); #ifndef ENABLE_SMALL ERR_free_strings(); #endif } void tls_clear_error() { ERR_clear_error (); } void tls_ctx_server_new(struct tls_root_ctx *ctx) { ASSERT(NULL != ctx); ctx->ctx = SSL_CTX_new (SSLv23_server_method ()); if (ctx->ctx == NULL) crypto_msg (M_FATAL, "SSL_CTX_new SSLv23_server_method"); } void tls_ctx_client_new(struct tls_root_ctx *ctx) { ASSERT(NULL != ctx); ctx->ctx = SSL_CTX_new (SSLv23_client_method ()); if (ctx->ctx == NULL) crypto_msg (M_FATAL, "SSL_CTX_new SSLv23_client_method"); } void tls_ctx_free(struct tls_root_ctx *ctx) { ASSERT(NULL != ctx); if (NULL != ctx->ctx) SSL_CTX_free (ctx->ctx); ctx->ctx = NULL; } bool tls_ctx_initialised(struct tls_root_ctx *ctx) { ASSERT(NULL != ctx); return NULL != ctx->ctx; } void key_state_export_keying_material(struct key_state_ssl *ssl, struct tls_session *session) { if (session->opt->ekm_size > 0) { #if (OPENSSL_VERSION_NUMBER >= 0x10001000) unsigned int size = session->opt->ekm_size; unsigned char ekm[size]; if (SSL_export_keying_material(ssl->ssl, ekm, sizeof(ekm), session->opt->ekm_label, session->opt->ekm_label_size, NULL, 0, 0)) { struct gc_arena gc = gc_new(); unsigned int len = (size * 2) + 2; const char *key = format_hex_ex (ekm, size, len, 0, NULL, &gc); setenv_str (session->opt->es, "exported_keying_material", key); dmsg(D_TLS_DEBUG_MED, "%s: exported keying material: %s", __func__, key); gc_free(&gc); } else { msg (M_WARN, "WARNING: Export keying material failed!"); setenv_del (session->opt->es, "exported_keying_material"); } #endif } } /* * Print debugging information on SSL/TLS session negotiation. */ #ifndef INFO_CALLBACK_SSL_CONST #define INFO_CALLBACK_SSL_CONST const #endif static void info_callback (INFO_CALLBACK_SSL_CONST SSL * s, int where, int ret) { if (where & SSL_CB_LOOP) { dmsg (D_HANDSHAKE_VERBOSE, "SSL state (%s): %s", where & SSL_ST_CONNECT ? "connect" : where & SSL_ST_ACCEPT ? "accept" : "undefined", SSL_state_string_long (s)); } else if (where & SSL_CB_ALERT) { dmsg (D_HANDSHAKE_VERBOSE, "SSL alert (%s): %s: %s", where & SSL_CB_READ ? "read" : "write", SSL_alert_type_string_long (ret), SSL_alert_desc_string_long (ret)); } } /* * Return maximum TLS version supported by local OpenSSL library. * Assume that presence of SSL_OP_NO_TLSvX macro indicates that * TLSvX is supported. */ int tls_version_max(void) { #if defined(SSL_OP_NO_TLSv1_2) return TLS_VER_1_2; #elif defined(SSL_OP_NO_TLSv1_1) return TLS_VER_1_1; #else return TLS_VER_1_0; #endif } void tls_ctx_set_options (struct tls_root_ctx *ctx, unsigned int ssl_flags) { ASSERT(NULL != ctx); /* process SSL options including minimum TLS version we will accept from peer */ { long sslopt = SSL_OP_SINGLE_DH_USE | SSL_OP_NO_TICKET | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3; int tls_ver_max = TLS_VER_UNSPEC; const int tls_ver_min = (ssl_flags >> SSLF_TLS_VERSION_MIN_SHIFT) & SSLF_TLS_VERSION_MIN_MASK; tls_ver_max = (ssl_flags >> SSLF_TLS_VERSION_MAX_SHIFT) & SSLF_TLS_VERSION_MAX_MASK; if (tls_ver_max <= TLS_VER_UNSPEC) tls_ver_max = tls_version_max(); if (tls_ver_min > TLS_VER_1_0 || tls_ver_max < TLS_VER_1_0) sslopt |= SSL_OP_NO_TLSv1; #ifdef SSL_OP_NO_TLSv1_1 if (tls_ver_min > TLS_VER_1_1 || tls_ver_max < TLS_VER_1_1) sslopt |= SSL_OP_NO_TLSv1_1; #endif #ifdef SSL_OP_NO_TLSv1_2 if (tls_ver_min > TLS_VER_1_2 || tls_ver_max < TLS_VER_1_2) sslopt |= SSL_OP_NO_TLSv1_2; #endif #ifdef SSL_OP_NO_COMPRESSION /* Disable compression - flag not available in OpenSSL 0.9.8 */ sslopt |= SSL_OP_NO_COMPRESSION; #endif SSL_CTX_set_options (ctx->ctx, sslopt); } #ifdef SSL_MODE_RELEASE_BUFFERS SSL_CTX_set_mode (ctx->ctx, SSL_MODE_RELEASE_BUFFERS); #endif SSL_CTX_set_session_cache_mode (ctx->ctx, SSL_SESS_CACHE_OFF); SSL_CTX_set_default_passwd_cb (ctx->ctx, pem_password_callback); /* Require peer certificate verification */ #if P2MP_SERVER if (ssl_flags & SSLF_CLIENT_CERT_NOT_REQUIRED) { msg (M_WARN, "WARNING: POTENTIALLY DANGEROUS OPTION " "--client-cert-not-required may accept clients which do not present " "a certificate"); } else #endif SSL_CTX_set_verify (ctx->ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, verify_callback); SSL_CTX_set_info_callback (ctx->ctx, info_callback); } void tls_ctx_restrict_ciphers(struct tls_root_ctx *ctx, const char *ciphers) { if (ciphers == NULL) { /* Use sane default (disable export, and unsupported cipher modes) */ if(!SSL_CTX_set_cipher_list(ctx->ctx, "DEFAULT:!EXP:!PSK:!SRP:!kRSA")) crypto_msg (M_FATAL, "Failed to set default TLS cipher list."); return; } /* Parse supplied cipher list and pass on to OpenSSL */ size_t begin_of_cipher, end_of_cipher; const char *current_cipher; size_t current_cipher_len; const tls_cipher_name_pair *cipher_pair; char openssl_ciphers[4096]; size_t openssl_ciphers_len = 0; openssl_ciphers[0] = '\0'; ASSERT(NULL != ctx); // Translate IANA cipher suite names to OpenSSL names begin_of_cipher = end_of_cipher = 0; for (; begin_of_cipher < strlen(ciphers); begin_of_cipher = end_of_cipher) { end_of_cipher += strcspn(&ciphers[begin_of_cipher], ":"); cipher_pair = tls_get_cipher_name_pair(&ciphers[begin_of_cipher], end_of_cipher - begin_of_cipher); if (NULL == cipher_pair) { // No translation found, use original current_cipher = &ciphers[begin_of_cipher]; current_cipher_len = end_of_cipher - begin_of_cipher; // Issue warning on missing translation // %.*s format specifier expects length of type int, so guarantee // that length is small enough and cast to int. msg (D_LOW, "No valid translation found for TLS cipher '%.*s'", constrain_int(current_cipher_len, 0, 256), current_cipher); } else { // Use OpenSSL name current_cipher = cipher_pair->openssl_name; current_cipher_len = strlen(current_cipher); if (end_of_cipher - begin_of_cipher == current_cipher_len && 0 != memcmp (&ciphers[begin_of_cipher], cipher_pair->iana_name, end_of_cipher - begin_of_cipher)) { // Non-IANA name used, show warning msg (M_WARN, "Deprecated TLS cipher name '%s', please use IANA name '%s'", cipher_pair->openssl_name, cipher_pair->iana_name); } } // Make sure new cipher name fits in cipher string if (((sizeof(openssl_ciphers)-1) - openssl_ciphers_len) < current_cipher_len) { msg (M_FATAL, "Failed to set restricted TLS cipher list, too long (>%d).", (int)sizeof(openssl_ciphers)-1); } // Concatenate cipher name to OpenSSL cipher string memcpy(&openssl_ciphers[openssl_ciphers_len], current_cipher, current_cipher_len); openssl_ciphers_len += current_cipher_len; openssl_ciphers[openssl_ciphers_len] = ':'; openssl_ciphers_len++; end_of_cipher++; } if (openssl_ciphers_len > 0) openssl_ciphers[openssl_ciphers_len-1] = '\0'; // Set OpenSSL cipher list if(!SSL_CTX_set_cipher_list(ctx->ctx, openssl_ciphers)) crypto_msg (M_FATAL, "Failed to set restricted TLS cipher list: %s", openssl_ciphers); } void tls_ctx_load_dh_params (struct tls_root_ctx *ctx, const char *dh_file, const char *dh_file_inline ) { DH *dh; BIO *bio; ASSERT(NULL != ctx); if (!strcmp (dh_file, INLINE_FILE_TAG) && dh_file_inline) { if (!(bio = BIO_new_mem_buf ((char *)dh_file_inline, -1))) crypto_msg (M_FATAL, "Cannot open memory BIO for inline DH parameters"); } else { /* Get Diffie Hellman Parameters */ if (!(bio = BIO_new_file (dh_file, "r"))) crypto_msg (M_FATAL, "Cannot open %s for DH parameters", dh_file); } dh = PEM_read_bio_DHparams (bio, NULL, NULL, NULL); BIO_free (bio); if (!dh) crypto_msg (M_FATAL, "Cannot load DH parameters from %s", dh_file); if (!SSL_CTX_set_tmp_dh (ctx->ctx, dh)) crypto_msg (M_FATAL, "SSL_CTX_set_tmp_dh"); msg (D_TLS_DEBUG_LOW, "Diffie-Hellman initialized with %d bit key", 8 * DH_size (dh)); DH_free (dh); } void tls_ctx_load_ecdh_params (struct tls_root_ctx *ctx, const char *curve_name ) { #ifndef OPENSSL_NO_EC int nid = NID_undef; EC_KEY *ecdh = NULL; const char *sname = NULL; /* Generate a new ECDH key for each SSL session (for non-ephemeral ECDH) */ SSL_CTX_set_options(ctx->ctx, SSL_OP_SINGLE_ECDH_USE); #if OPENSSL_VERSION_NUMBER >= 0x10002000L /* OpenSSL 1.0.2 and newer can automatically handle ECDH parameter loading */ if (NULL == curve_name) { SSL_CTX_set_ecdh_auto(ctx->ctx, 1); return; } #endif /* For older OpenSSL, we'll have to do the parameter loading on our own */ if (curve_name != NULL) { /* Use user supplied curve if given */ msg (D_TLS_DEBUG, "Using user specified ECDH curve (%s)", curve_name); nid = OBJ_sn2nid(curve_name); } else { /* Extract curve from key */ EC_KEY *eckey = NULL; const EC_GROUP *ecgrp = NULL; EVP_PKEY *pkey = NULL; /* Little hack to get private key ref from SSL_CTX, yay OpenSSL... */ SSL ssl; ssl.cert = ctx->ctx->cert; pkey = SSL_get_privatekey(&ssl); msg (D_TLS_DEBUG, "Extracting ECDH curve from private key"); if (pkey != NULL && (eckey = EVP_PKEY_get1_EC_KEY(pkey)) != NULL && (ecgrp = EC_KEY_get0_group(eckey)) != NULL) nid = EC_GROUP_get_curve_name(ecgrp); } /* Translate NID back to name , just for kicks */ sname = OBJ_nid2sn(nid); if (sname == NULL) sname = "(Unknown)"; /* Create new EC key and set as ECDH key */ if (NID_undef == nid || NULL == (ecdh = EC_KEY_new_by_curve_name(nid))) { /* Creating key failed, fall back on sane default */ ecdh = EC_KEY_new_by_curve_name(NID_secp384r1); const char *source = (NULL == curve_name) ? "extract curve from certificate" : "use supplied curve"; msg (D_TLS_DEBUG_LOW, "Failed to %s (%s), using secp384r1 instead.", source, sname); sname = OBJ_nid2sn(NID_secp384r1); } if (!SSL_CTX_set_tmp_ecdh(ctx->ctx, ecdh)) crypto_msg (M_FATAL, "SSL_CTX_set_tmp_ecdh: cannot add curve"); msg (D_TLS_DEBUG_LOW, "ECDH curve %s added", sname); EC_KEY_free(ecdh); #else msg (M_DEBUG, "Your OpenSSL library was built without elliptic curve support." " Skipping ECDH parameter loading."); #endif /* OPENSSL_NO_EC */ } int tls_ctx_load_pkcs12(struct tls_root_ctx *ctx, const char *pkcs12_file, const char *pkcs12_file_inline, bool load_ca_file ) { FILE *fp; EVP_PKEY *pkey; X509 *cert; STACK_OF(X509) *ca = NULL; PKCS12 *p12; int i; char password[256]; ASSERT(NULL != ctx); if (!strcmp (pkcs12_file, INLINE_FILE_TAG) && pkcs12_file_inline) { BIO *b64 = BIO_new(BIO_f_base64()); BIO *bio = BIO_new_mem_buf((void *) pkcs12_file_inline, (int) strlen(pkcs12_file_inline)); ASSERT(b64 && bio); BIO_push(b64, bio); p12 = d2i_PKCS12_bio(b64, NULL); if (!p12) crypto_msg (M_FATAL, "Error reading inline PKCS#12 file"); BIO_free(b64); BIO_free(bio); } else { /* Load the PKCS #12 file */ if (!(fp = platform_fopen(pkcs12_file, "rb"))) crypto_msg (M_FATAL, "Error opening file %s", pkcs12_file); p12 = d2i_PKCS12_fp(fp, NULL); fclose(fp); if (!p12) crypto_msg (M_FATAL, "Error reading PKCS#12 file %s", pkcs12_file); } /* Parse the PKCS #12 file */ if (!PKCS12_parse(p12, "", &pkey, &cert, &ca)) { pem_password_callback (password, sizeof(password) - 1, 0, NULL); /* Reparse the PKCS #12 file with password */ ca = NULL; if (!PKCS12_parse(p12, password, &pkey, &cert, &ca)) { #ifdef ENABLE_MANAGEMENT if (management && (ERR_GET_REASON (ERR_peek_error()) == PKCS12_R_MAC_VERIFY_FAILURE)) management_auth_failure (management, UP_TYPE_PRIVATE_KEY, NULL); #endif PKCS12_free(p12); return 1; } } PKCS12_free(p12); /* Load Certificate */ if (!SSL_CTX_use_certificate (ctx->ctx, cert)) crypto_msg (M_FATAL, "Cannot use certificate"); /* Load Private Key */ if (!SSL_CTX_use_PrivateKey (ctx->ctx, pkey)) crypto_msg (M_FATAL, "Cannot use private key"); warn_if_group_others_accessible (pkcs12_file); /* Check Private Key */ if (!SSL_CTX_check_private_key (ctx->ctx)) crypto_msg (M_FATAL, "Private key does not match the certificate"); /* Set Certificate Verification chain */ if (load_ca_file) { /* Add CAs from PKCS12 to the cert store and mark them as trusted. * They're also used to fill in the chain of intermediate certs as * necessary. */ if (ca && sk_X509_num(ca)) { for (i = 0; i < sk_X509_num(ca); i++) { if (!X509_STORE_add_cert(ctx->ctx->cert_store,sk_X509_value(ca, i))) crypto_msg (M_FATAL,"Cannot add certificate to certificate chain (X509_STORE_add_cert)"); if (!SSL_CTX_add_client_CA(ctx->ctx, sk_X509_value(ca, i))) crypto_msg (M_FATAL,"Cannot add certificate to client CA list (SSL_CTX_add_client_CA)"); } } } else { /* If trusted CA certs were loaded from a PEM file, and we ignore the * ones in PKCS12, do load PKCS12-provided certs to the client extra * certs chain just in case they include intermediate CAs needed to * prove my identity to the other end. This does not make them trusted. */ if (ca && sk_X509_num(ca)) { for (i = 0; i < sk_X509_num(ca); i++) { if (!SSL_CTX_add_extra_chain_cert(ctx->ctx,sk_X509_value(ca, i))) crypto_msg (M_FATAL, "Cannot add extra certificate to chain (SSL_CTX_add_extra_chain_cert)"); } } } return 0; } #ifdef ENABLE_CRYPTOAPI void tls_ctx_load_cryptoapi(struct tls_root_ctx *ctx, const char *cryptoapi_cert) { ASSERT(NULL != ctx); /* Load Certificate and Private Key */ if (!SSL_CTX_use_CryptoAPI_certificate (ctx->ctx, cryptoapi_cert)) crypto_msg (M_FATAL, "Cannot load certificate \"%s\" from Microsoft Certificate Store", cryptoapi_cert); } #endif /* WIN32 */ static void tls_ctx_add_extra_certs (struct tls_root_ctx *ctx, BIO *bio) { X509 *cert; for (;;) { cert = NULL; if (!PEM_read_bio_X509 (bio, &cert, 0, NULL)) /* takes ownership of cert */ break; if (!cert) crypto_msg (M_FATAL, "Error reading extra certificate"); if (SSL_CTX_add_extra_chain_cert(ctx->ctx, cert) != 1) crypto_msg (M_FATAL, "Error adding extra certificate"); } } /* Like tls_ctx_load_cert, but returns a copy of the certificate in **X509 */ static void tls_ctx_load_cert_file_and_copy (struct tls_root_ctx *ctx, const char *cert_file, const char *cert_file_inline, X509 **x509 ) { BIO *in = NULL; X509 *x = NULL; int ret = 0; bool inline_file = false; ASSERT (NULL != ctx); if (NULL != x509) ASSERT (NULL == *x509); inline_file = (strcmp (cert_file, INLINE_FILE_TAG) == 0); if (inline_file && cert_file_inline) in = BIO_new_mem_buf ((char *)cert_file_inline, -1); else in = BIO_new_file (cert_file, "r"); if (in == NULL) { SSLerr (SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_SYS_LIB); goto end; } x = PEM_read_bio_X509 (in, NULL, ctx->ctx->default_passwd_callback, ctx->ctx->default_passwd_callback_userdata); if (x == NULL) { SSLerr (SSL_F_SSL_CTX_USE_CERTIFICATE_FILE, ERR_R_PEM_LIB); goto end; } ret = SSL_CTX_use_certificate (ctx->ctx, x); if (ret) tls_ctx_add_extra_certs (ctx, in); end: if (!ret) { if (inline_file) crypto_msg (M_FATAL, "Cannot load inline certificate file"); else crypto_msg (M_FATAL, "Cannot load certificate file %s", cert_file); } if (in != NULL) BIO_free(in); if (x509) *x509 = x; else if (x) X509_free (x); } void tls_ctx_load_cert_file (struct tls_root_ctx *ctx, const char *cert_file, const char *cert_file_inline) { tls_ctx_load_cert_file_and_copy (ctx, cert_file, cert_file_inline, NULL); } void tls_ctx_free_cert_file (X509 *x509) { X509_free(x509); } int tls_ctx_load_priv_file (struct tls_root_ctx *ctx, const char *priv_key_file, const char *priv_key_file_inline ) { SSL_CTX *ssl_ctx = NULL; BIO *in = NULL; EVP_PKEY *pkey = NULL; int ret = 1; ASSERT(NULL != ctx); ssl_ctx = ctx->ctx; if (!strcmp (priv_key_file, INLINE_FILE_TAG) && priv_key_file_inline) in = BIO_new_mem_buf ((char *)priv_key_file_inline, -1); else in = BIO_new_file (priv_key_file, "r"); if (!in) goto end; pkey = PEM_read_bio_PrivateKey (in, NULL, ssl_ctx->default_passwd_callback, ssl_ctx->default_passwd_callback_userdata); if (!pkey) goto end; if (!SSL_CTX_use_PrivateKey (ssl_ctx, pkey)) { #ifdef ENABLE_MANAGEMENT if (management && (ERR_GET_REASON (ERR_peek_error()) == EVP_R_BAD_DECRYPT)) management_auth_failure (management, UP_TYPE_PRIVATE_KEY, NULL); #endif crypto_msg (M_WARN, "Cannot load private key file %s", priv_key_file); goto end; } warn_if_group_others_accessible (priv_key_file); /* Check Private Key */ if (!SSL_CTX_check_private_key (ssl_ctx)) crypto_msg (M_FATAL, "Private key does not match the certificate"); ret = 0; end: if (pkey) EVP_PKEY_free (pkey); if (in) BIO_free (in); return ret; } #ifdef MANAGMENT_EXTERNAL_KEY /* encrypt */ static int rsa_pub_enc(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) { ASSERT(0); return -1; } /* verify arbitrary data */ static int rsa_pub_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) { ASSERT(0); return -1; } /* decrypt */ static int rsa_priv_dec(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) { ASSERT(0); return -1; } /* called at RSA_free */ static int rsa_finish(RSA *rsa) { free ((void*)rsa->meth); rsa->meth = NULL; return 1; } /* sign arbitrary data */ static int rsa_priv_enc(int flen, const unsigned char *from, unsigned char *to, RSA *rsa, int padding) { /* optional app data in rsa->meth->app_data; */ char *in_b64 = NULL; char *out_b64 = NULL; int ret = -1; int len; if (padding != RSA_PKCS1_PADDING) { RSAerr (RSA_F_RSA_EAY_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE); goto done; } /* convert 'from' to base64 */ if (openvpn_base64_encode (from, flen, &in_b64) <= 0) goto done; /* call MI for signature */ if (management) out_b64 = management_query_rsa_sig (management, in_b64); if (!out_b64) goto done; /* decode base64 signature to binary */ len = RSA_size(rsa); ret = openvpn_base64_decode (out_b64, to, len); /* verify length */ if (ret != len) ret = -1; done: if (in_b64) free (in_b64); if (out_b64) free (out_b64); return ret; } int tls_ctx_use_external_private_key (struct tls_root_ctx *ctx, const char *cert_file, const char *cert_file_inline) { RSA *rsa = NULL; RSA *pub_rsa; RSA_METHOD *rsa_meth; X509 *cert = NULL; ASSERT (NULL != ctx); tls_ctx_load_cert_file_and_copy (ctx, cert_file, cert_file_inline, &cert); ASSERT (NULL != cert); /* allocate custom RSA method object */ ALLOC_OBJ_CLEAR (rsa_meth, RSA_METHOD); rsa_meth->name = "OpenVPN external private key RSA Method"; rsa_meth->rsa_pub_enc = rsa_pub_enc; rsa_meth->rsa_pub_dec = rsa_pub_dec; rsa_meth->rsa_priv_enc = rsa_priv_enc; rsa_meth->rsa_priv_dec = rsa_priv_dec; rsa_meth->init = NULL; rsa_meth->finish = rsa_finish; rsa_meth->flags = RSA_METHOD_FLAG_NO_CHECK; rsa_meth->app_data = NULL; /* allocate RSA object */ rsa = RSA_new(); if (rsa == NULL) { SSLerr(SSL_F_SSL_USE_PRIVATEKEY, ERR_R_MALLOC_FAILURE); goto err; } /* get the public key */ ASSERT(cert->cert_info->key->pkey); /* NULL before SSL_CTX_use_certificate() is called */ pub_rsa = cert->cert_info->key->pkey->pkey.rsa; /* initialize RSA object */ rsa->n = BN_dup(pub_rsa->n); rsa->flags |= RSA_FLAG_EXT_PKEY; if (!RSA_set_method(rsa, rsa_meth)) goto err; /* bind our custom RSA object to ssl_ctx */ if (!SSL_CTX_use_RSAPrivateKey(ctx->ctx, rsa)) goto err; X509_free(cert); RSA_free(rsa); /* doesn't necessarily free, just decrements refcount */ return 1; err: if (cert) X509_free(cert); if (rsa) RSA_free(rsa); else { if (rsa_meth) free(rsa_meth); } crypto_msg (M_FATAL, "Cannot enable SSL external private key capability"); return 0; } #endif static int sk_x509_name_cmp(const X509_NAME * const *a, const X509_NAME * const *b) { return X509_NAME_cmp (*a, *b); } void tls_ctx_load_ca (struct tls_root_ctx *ctx, const char *ca_file, const char *ca_file_inline, const char *ca_path, bool tls_server ) { STACK_OF(X509_INFO) *info_stack = NULL; STACK_OF(X509_NAME) *cert_names = NULL; X509_LOOKUP *lookup = NULL; X509_STORE *store = NULL; X509_NAME *xn = NULL; BIO *in = NULL; int i, added = 0, prev = 0; ASSERT(NULL != ctx); store = SSL_CTX_get_cert_store(ctx->ctx); if (!store) crypto_msg (M_FATAL, "Cannot get certificate store"); /* Try to add certificates and CRLs from ca_file */ if (ca_file) { if (!strcmp (ca_file, INLINE_FILE_TAG) && ca_file_inline) in = BIO_new_mem_buf ((char *)ca_file_inline, -1); else in = BIO_new_file (ca_file, "r"); if (in) info_stack = PEM_X509_INFO_read_bio (in, NULL, NULL, NULL); if (info_stack) { for (i = 0; i < sk_X509_INFO_num (info_stack); i++) { X509_INFO *info = sk_X509_INFO_value (info_stack, i); if (info->crl) X509_STORE_add_crl (store, info->crl); if (tls_server && !info->x509) { crypto_msg (M_FATAL, "X509 name was missing in TLS mode"); } if (info->x509) { X509_STORE_add_cert (store, info->x509); added++; if (!tls_server) continue; /* Use names of CAs as a client CA list */ if (cert_names == NULL) { cert_names = sk_X509_NAME_new (sk_x509_name_cmp); if (!cert_names) continue; } xn = X509_get_subject_name (info->x509); if (!xn) continue; /* Don't add duplicate CA names */ if (sk_X509_NAME_find (cert_names, xn) == -1) { xn = X509_NAME_dup (xn); if (!xn) continue; sk_X509_NAME_push (cert_names, xn); } } if (tls_server) { int cnum = sk_X509_NAME_num (cert_names); if (cnum != (prev + 1)) { crypto_msg (M_WARN, "Cannot load CA certificate file %s (entry %d did not validate)", np(ca_file), added); } prev = cnum; } } sk_X509_INFO_pop_free (info_stack, X509_INFO_free); } if (tls_server) SSL_CTX_set_client_CA_list (ctx->ctx, cert_names); if (!added) { crypto_msg (M_FATAL, "Cannot load CA certificate file %s (no entries were read)", np(ca_file)); } if (tls_server) { int cnum = sk_X509_NAME_num (cert_names); if (cnum != added) { crypto_msg (M_FATAL, "Cannot load CA certificate file %s (only %d " "of %d entries were valid X509 names)", np(ca_file), cnum, added); } } if (in) BIO_free (in); } /* Set a store for certs (CA & CRL) with a lookup on the "capath" hash directory */ if (ca_path) { lookup = X509_STORE_add_lookup (store, X509_LOOKUP_hash_dir ()); if (lookup && X509_LOOKUP_add_dir (lookup, ca_path, X509_FILETYPE_PEM)) msg(M_WARN, "WARNING: experimental option --capath %s", ca_path); else crypto_msg (M_FATAL, "Cannot add lookup at --capath %s", ca_path); X509_STORE_set_flags (store, X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL); } } void tls_ctx_load_extra_certs (struct tls_root_ctx *ctx, const char *extra_certs_file, const char *extra_certs_file_inline ) { BIO *in; if (!strcmp (extra_certs_file, INLINE_FILE_TAG) && extra_certs_file_inline) in = BIO_new_mem_buf ((char *)extra_certs_file_inline, -1); else in = BIO_new_file (extra_certs_file, "r"); if (in == NULL) crypto_msg (M_FATAL, "Cannot load extra-certs file: %s", extra_certs_file); else tls_ctx_add_extra_certs (ctx, in); BIO_free (in); } /* ************************************** * * Key-state specific functions * ***************************************/ /* * * BIO functions * */ #ifdef BIO_DEBUG #warning BIO_DEBUG defined static FILE *biofp; /* GLOBAL */ static bool biofp_toggle; /* GLOBAL */ static time_t biofp_last_open; /* GLOBAL */ static const int biofp_reopen_interval = 600; /* GLOBAL */ static void close_biofp() { if (biofp) { ASSERT (!fclose (biofp)); biofp = NULL; } } static void open_biofp() { const time_t current = time (NULL); const pid_t pid = getpid (); if (biofp_last_open + biofp_reopen_interval < current) close_biofp(); if (!biofp) { char fn[256]; openvpn_snprintf(fn, sizeof(fn), "bio/%d-%d.log", pid, biofp_toggle); biofp = fopen (fn, "w"); ASSERT (biofp); biofp_last_open = time (NULL); biofp_toggle ^= 1; } } static void bio_debug_data (const char *mode, BIO *bio, const uint8_t *buf, int len, const char *desc) { struct gc_arena gc = gc_new (); if (len > 0) { open_biofp(); fprintf(biofp, "BIO_%s %s time=" time_format " bio=" ptr_format " len=%d data=%s\n", mode, desc, time (NULL), (ptr_type)bio, len, format_hex (buf, len, 0, &gc)); fflush (biofp); } gc_free (&gc); } static void bio_debug_oc (const char *mode, BIO *bio) { open_biofp(); fprintf(biofp, "BIO %s time=" time_format " bio=" ptr_format "\n", mode, time (NULL), (ptr_type)bio); fflush (biofp); } #endif /* * OpenVPN's interface to SSL/TLS authentication, * encryption, and decryption is exclusively * through "memory BIOs". */ static BIO * getbio (BIO_METHOD * type, const char *desc) { BIO *ret; ret = BIO_new (type); if (!ret) crypto_msg (M_FATAL, "Error creating %s BIO", desc); return ret; } /* * Write to an OpenSSL BIO in non-blocking mode. */ static int bio_write (BIO *bio, const uint8_t *data, int size, const char *desc) { int i; int ret = 0; ASSERT (size >= 0); if (size) { /* * Free the L_TLS lock prior to calling BIO routines * so that foreground thread can still call * tls_pre_decrypt or tls_pre_encrypt, * allowing tunnel packet forwarding to continue. */ #ifdef BIO_DEBUG bio_debug_data ("write", bio, data, size, desc); #endif i = BIO_write (bio, data, size); if (i < 0) { if (BIO_should_retry (bio)) { ; } else { crypto_msg (D_TLS_ERRORS, "TLS ERROR: BIO write %s error", desc); ret = -1; ERR_clear_error (); } } else if (i != size) { crypto_msg (D_TLS_ERRORS, "TLS ERROR: BIO write %s incomplete %d/%d", desc, i, size); ret = -1; ERR_clear_error (); } else { /* successful write */ dmsg (D_HANDSHAKE_VERBOSE, "BIO write %s %d bytes", desc, i); ret = 1; } } return ret; } /* * Inline functions for reading from and writing * to BIOs. */ static void bio_write_post (const int status, struct buffer *buf) { if (status == 1) /* success status return from bio_write? */ { memset (BPTR (buf), 0, BLEN (buf)); /* erase data just written */ buf->len = 0; } } /* * Read from an OpenSSL BIO in non-blocking mode. */ static int bio_read (BIO *bio, struct buffer *buf, int maxlen, const char *desc) { int i; int ret = 0; ASSERT (buf->len >= 0); if (buf->len) { ; } else { int len = buf_forward_capacity (buf); if (maxlen < len) len = maxlen; /* * BIO_read brackets most of the serious RSA * key negotiation number crunching. */ i = BIO_read (bio, BPTR (buf), len); VALGRIND_MAKE_READABLE ((void *) &i, sizeof (i)); #ifdef BIO_DEBUG bio_debug_data ("read", bio, BPTR (buf), i, desc); #endif if (i < 0) { if (BIO_should_retry (bio)) { ; } else { crypto_msg (D_TLS_ERRORS, "TLS_ERROR: BIO read %s error", desc); buf->len = 0; ret = -1; ERR_clear_error (); } } else if (!i) { buf->len = 0; } else { /* successful read */ dmsg (D_HANDSHAKE_VERBOSE, "BIO read %s %d bytes", desc, i); buf->len = i; ret = 1; VALGRIND_MAKE_READABLE ((void *) BPTR (buf), BLEN (buf)); } } return ret; } void key_state_ssl_init(struct key_state_ssl *ks_ssl, const struct tls_root_ctx *ssl_ctx, bool is_server, struct tls_session *session) { ASSERT(NULL != ssl_ctx); ASSERT(ks_ssl); CLEAR (*ks_ssl); ks_ssl->ssl = SSL_new (ssl_ctx->ctx); if (!ks_ssl->ssl) crypto_msg (M_FATAL, "SSL_new failed"); /* put session * in ssl object so we can access it from verify callback*/ SSL_set_ex_data (ks_ssl->ssl, mydata_index, session); ks_ssl->ssl_bio = getbio (BIO_f_ssl (), "ssl_bio"); ks_ssl->ct_in = getbio (BIO_s_mem (), "ct_in"); ks_ssl->ct_out = getbio (BIO_s_mem (), "ct_out"); #ifdef BIO_DEBUG bio_debug_oc ("open ssl_bio", ks_ssl->ssl_bio); bio_debug_oc ("open ct_in", ks_ssl->ct_in); bio_debug_oc ("open ct_out", ks_ssl->ct_out); #endif if (is_server) SSL_set_accept_state (ks_ssl->ssl); else SSL_set_connect_state (ks_ssl->ssl); SSL_set_bio (ks_ssl->ssl, ks_ssl->ct_in, ks_ssl->ct_out); BIO_set_ssl (ks_ssl->ssl_bio, ks_ssl->ssl, BIO_NOCLOSE); } void key_state_ssl_free(struct key_state_ssl *ks_ssl) { if (ks_ssl->ssl) { #ifdef BIO_DEBUG bio_debug_oc ("close ssl_bio", ks_ssl->ssl_bio); bio_debug_oc ("close ct_in", ks_ssl->ct_in); bio_debug_oc ("close ct_out", ks_ssl->ct_out); #endif BIO_free_all(ks_ssl->ssl_bio); SSL_free (ks_ssl->ssl); } } int key_state_write_plaintext (struct key_state_ssl *ks_ssl, struct buffer *buf) { int ret = 0; perf_push (PERF_BIO_WRITE_PLAINTEXT); #ifdef ENABLE_CRYPTO_OPENSSL ASSERT (NULL != ks_ssl); ret = bio_write (ks_ssl->ssl_bio, BPTR(buf), BLEN(buf), "tls_write_plaintext"); bio_write_post (ret, buf); #endif /* ENABLE_CRYPTO_OPENSSL */ perf_pop (); return ret; } int key_state_write_plaintext_const (struct key_state_ssl *ks_ssl, const uint8_t *data, int len) { int ret = 0; perf_push (PERF_BIO_WRITE_PLAINTEXT); ASSERT (NULL != ks_ssl); ret = bio_write (ks_ssl->ssl_bio, data, len, "tls_write_plaintext_const"); perf_pop (); return ret; } int key_state_read_ciphertext (struct key_state_ssl *ks_ssl, struct buffer *buf, int maxlen) { int ret = 0; perf_push (PERF_BIO_READ_CIPHERTEXT); ASSERT (NULL != ks_ssl); ret = bio_read (ks_ssl->ct_out, buf, maxlen, "tls_read_ciphertext"); perf_pop (); return ret; } int key_state_write_ciphertext (struct key_state_ssl *ks_ssl, struct buffer *buf) { int ret = 0; perf_push (PERF_BIO_WRITE_CIPHERTEXT); ASSERT (NULL != ks_ssl); ret = bio_write (ks_ssl->ct_in, BPTR(buf), BLEN(buf), "tls_write_ciphertext"); bio_write_post (ret, buf); perf_pop (); return ret; } int key_state_read_plaintext (struct key_state_ssl *ks_ssl, struct buffer *buf, int maxlen) { int ret = 0; perf_push (PERF_BIO_READ_PLAINTEXT); ASSERT (NULL != ks_ssl); ret = bio_read (ks_ssl->ssl_bio, buf, maxlen, "tls_read_plaintext"); perf_pop (); return ret; } /* ************************************** * * Information functions * * Print information for the end user. * ***************************************/ void print_details (struct key_state_ssl * ks_ssl, const char *prefix) { const SSL_CIPHER *ciph; X509 *cert; char s1[256]; char s2[256]; s1[0] = s2[0] = 0; ciph = SSL_get_current_cipher (ks_ssl->ssl); openvpn_snprintf (s1, sizeof (s1), "%s %s, cipher %s %s", prefix, SSL_get_version (ks_ssl->ssl), SSL_CIPHER_get_version (ciph), SSL_CIPHER_get_name (ciph)); cert = SSL_get_peer_certificate (ks_ssl->ssl); if (cert != NULL) { EVP_PKEY *pkey = X509_get_pubkey (cert); if (pkey != NULL) { if (pkey->type == EVP_PKEY_RSA && pkey->pkey.rsa != NULL && pkey->pkey.rsa->n != NULL) { openvpn_snprintf (s2, sizeof (s2), ", %d bit RSA", BN_num_bits (pkey->pkey.rsa->n)); } else if (pkey->type == EVP_PKEY_DSA && pkey->pkey.dsa != NULL && pkey->pkey.dsa->p != NULL) { openvpn_snprintf (s2, sizeof (s2), ", %d bit DSA", BN_num_bits (pkey->pkey.dsa->p)); } EVP_PKEY_free (pkey); } X509_free (cert); } /* The SSL API does not allow us to look at temporary RSA/DH keys, * otherwise we should print their lengths too */ msg (D_HANDSHAKE, "%s%s", s1, s2); } void show_available_tls_ciphers (const char *cipher_list) { struct tls_root_ctx tls_ctx; SSL *ssl; const char *cipher_name; const tls_cipher_name_pair *pair; int priority = 0; tls_ctx.ctx = SSL_CTX_new (SSLv23_method ()); if (!tls_ctx.ctx) crypto_msg (M_FATAL, "Cannot create SSL_CTX object"); ssl = SSL_new (tls_ctx.ctx); if (!ssl) crypto_msg (M_FATAL, "Cannot create SSL object"); tls_ctx_restrict_ciphers(&tls_ctx, cipher_list); printf ("Available TLS Ciphers,\n"); printf ("listed in order of preference:\n\n"); while ((cipher_name = SSL_get_cipher_list (ssl, priority++))) { pair = tls_get_cipher_name_pair(cipher_name, strlen(cipher_name)); if (NULL == pair) { // No translation found, print warning printf ("%s (No IANA name known to OpenVPN, use OpenSSL name.)\n", cipher_name); } else { printf ("%s\n", pair->iana_name); } } printf ("\n" SHOW_TLS_CIPHER_LIST_WARNING); SSL_free (ssl); SSL_CTX_free (tls_ctx.ctx); } /* * Show the Elliptic curves that are available for us to use * in the OpenSSL library. */ void show_available_curves() { #ifndef OPENSSL_NO_EC EC_builtin_curve *curves = NULL; size_t crv_len = 0; size_t n = 0; crv_len = EC_get_builtin_curves(NULL, 0); curves = OPENSSL_malloc((int)(sizeof(EC_builtin_curve) * crv_len)); if (curves == NULL) crypto_msg (M_FATAL, "Cannot create EC_builtin_curve object"); else { if (EC_get_builtin_curves(curves, crv_len)) { printf ("Available Elliptic curves:\n"); for (n = 0; n < crv_len; n++) { const char *sname; sname = OBJ_nid2sn(curves[n].nid); if (sname == NULL) sname = ""; printf("%s\n", sname); } } else { crypto_msg (M_FATAL, "Cannot get list of builtin curves"); } OPENSSL_free(curves); } #else msg (M_WARN, "Your OpenSSL library was built without elliptic curve support. " "No curves available."); #endif } void get_highest_preference_tls_cipher (char *buf, int size) { SSL_CTX *ctx; SSL *ssl; const char *cipher_name; ctx = SSL_CTX_new (SSLv23_method ()); if (!ctx) crypto_msg (M_FATAL, "Cannot create SSL_CTX object"); ssl = SSL_new (ctx); if (!ssl) crypto_msg (M_FATAL, "Cannot create SSL object"); cipher_name = SSL_get_cipher_list (ssl, 0); strncpynt (buf, cipher_name, size); SSL_free (ssl); SSL_CTX_free (ctx); } const char * get_ssl_library_version(void) { return SSLeay_version(SSLEAY_VERSION); } #endif /* defined(ENABLE_CRYPTO) && defined(ENABLE_CRYPTO_OPENSSL) */