diff options
Diffstat (limited to 'src/openvpn/ssl_openssl.c')
| -rw-r--r-- | src/openvpn/ssl_openssl.c | 1175 |
1 files changed, 1175 insertions, 0 deletions
diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c new file mode 100644 index 0000000..a727b60 --- /dev/null +++ b/src/openvpn/ssl_openssl.c @@ -0,0 +1,1175 @@ +/* + * 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. <sales@openvpn.net> + * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com> + * + * 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_SSL) && 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 <openssl/err.h> +#include <openssl/pkcs12.h> +#include <openssl/x509.h> +#include <openssl/crypto.h> + +/* + * 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 (); +} + +/* + * OpenSSL callback to get a temporary RSA key, mostly + * used for export ciphers. + */ +static RSA * +tmp_rsa_cb (SSL * s, int is_export, int keylength) +{ + static RSA *rsa_tmp = NULL; + if (rsa_tmp == NULL) + { + msg (D_HANDSHAKE, "Generating temp (%d bit) RSA key", keylength); + rsa_tmp = RSA_generate_key (keylength, RSA_F4, NULL, NULL); + } + return (rsa_tmp); +} + +void +tls_ctx_server_new(struct tls_root_ctx *ctx) +{ + ASSERT(NULL != ctx); + + ctx->ctx = SSL_CTX_new (TLSv1_server_method ()); + + if (ctx->ctx == NULL) + msg (M_SSLERR, "SSL_CTX_new TLSv1_server_method"); + + SSL_CTX_set_tmp_rsa_callback (ctx->ctx, tmp_rsa_cb); +} + +void +tls_ctx_client_new(struct tls_root_ctx *ctx) +{ + ASSERT(NULL != ctx); + + ctx->ctx = SSL_CTX_new (TLSv1_client_method ()); + + if (ctx->ctx == NULL) + msg (M_SSLERR, "SSL_CTX_new TLSv1_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; +} + +/* + * 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)); + } +} + +void +tls_ctx_set_options (struct tls_root_ctx *ctx, unsigned int ssl_flags) +{ + ASSERT(NULL != ctx); + + SSL_CTX_set_session_cache_mode (ctx->ctx, SSL_SESS_CACHE_OFF); + SSL_CTX_set_options (ctx->ctx, SSL_OP_SINGLE_DH_USE); + 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) +{ + ASSERT(NULL != ctx); + + if(!SSL_CTX_set_cipher_list(ctx->ctx, ciphers)) + msg(M_SSLERR, "Failed to set restricted TLS cipher list: %s", 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))) + msg (M_SSLERR, "Cannot open memory BIO for inline DH parameters"); + } + else + { + /* Get Diffie Hellman Parameters */ + if (!(bio = BIO_new_file (dh_file, "r"))) + msg (M_SSLERR, "Cannot open %s for DH parameters", dh_file); + } + + dh = PEM_read_bio_DHparams (bio, NULL, NULL, NULL); + BIO_free (bio); + + if (!dh) + msg (M_SSLERR, "Cannot load DH parameters from %s", dh_file); + if (!SSL_CTX_set_tmp_dh (ctx->ctx, dh)) + msg (M_SSLERR, "SSL_CTX_set_tmp_dh"); + + msg (D_TLS_DEBUG_LOW, "Diffie-Hellman initialized with %d bit key", + 8 * DH_size (dh)); + + DH_free (dh); +} + +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) + msg(M_SSLERR, "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"))) + msg(M_SSLERR, "Error opening file %s", pkcs12_file); + p12 = d2i_PKCS12_fp(fp, NULL); + fclose(fp); + if (!p12) + msg(M_SSLERR, "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)) + msg (M_SSLERR, "Cannot use certificate"); + + /* Load Private Key */ + if (!SSL_CTX_use_PrivateKey (ctx->ctx, pkey)) + msg (M_SSLERR, "Cannot use private key"); + warn_if_group_others_accessible (pkcs12_file); + + /* Check Private Key */ + if (!SSL_CTX_check_private_key (ctx->ctx)) + msg (M_SSLERR, "Private key does not match the certificate"); + + /* Set Certificate Verification chain */ + if (load_ca_file) + { + 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))) + msg (M_SSLERR, "Cannot add certificate to certificate chain (X509_STORE_add_cert)"); + if (!SSL_CTX_add_client_CA(ctx->ctx, sk_X509_value(ca, i))) + msg (M_SSLERR, "Cannot add certificate to client CA list (SSL_CTX_add_client_CA)"); + } + } + } + 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)) + msg (M_SSLERR, "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) + msg (M_SSLERR, "Error reading extra certificate"); + if (SSL_CTX_add_extra_chain_cert(ctx->ctx, cert) != 1) + msg (M_SSLERR, "Error adding extra certificate"); + } +} + +void +tls_ctx_load_cert_file (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) + msg (M_SSLERR, "Cannot load inline certificate file"); + else + msg (M_SSLERR, "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_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 + ) +{ + int status; + 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 + msg (M_WARN|M_SSL, "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)) + msg (M_SSLERR, "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, X509 *cert) +{ + RSA *rsa = NULL; + RSA *pub_rsa; + RSA_METHOD *rsa_meth; + + ASSERT (NULL != ctx); + 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; + + RSA_free(rsa); /* doesn't necessarily free, just decrements refcount */ + return 1; + + err: + if (rsa) + RSA_free(rsa); + else + { + if (rsa_meth) + free(rsa_meth); + } + msg (M_SSLERR, "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; + + ASSERT(NULL != ctx); + + store = SSL_CTX_get_cert_store(ctx->ctx); + if (!store) + msg(M_SSLERR, "Cannot get certificate store (SSL_CTX_get_cert_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 (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); + } + } + } + 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 || (tls_server && sk_X509_NAME_num (cert_names) != added)) + msg (M_SSLERR, "Cannot load CA certificate file %s", np(ca_file)); + 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 + msg(M_SSLERR, "Cannot add lookup at --capath %s", ca_path); +#if OPENSSL_VERSION_NUMBER >= 0x00907000L + X509_STORE_set_flags (store, X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL); +#else + msg(M_WARN, "WARNING: this version of OpenSSL cannot handle CRL files in capath"); +#endif + } +} + +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) + msg (M_SSLERR, "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) + msg (M_SSLERR, "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 + { + msg (D_TLS_ERRORS | M_SSL, "TLS ERROR: BIO write %s error", + desc); + ret = -1; + ERR_clear_error (); + } + } + else if (i != size) + { + msg (D_TLS_ERRORS | M_SSL, + "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 + { + msg (D_TLS_ERRORS | M_SSL, "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, void *session) +{ + ASSERT(NULL != ssl_ctx); + ASSERT(ks_ssl); + CLEAR (*ks_ssl); + + ks_ssl->ssl = SSL_new (ssl_ctx->ctx); + if (!ks_ssl->ssl) + msg (M_SSLERR, "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 () +{ + SSL_CTX *ctx; + SSL *ssl; + const char *cipher_name; + int priority = 0; + + ctx = SSL_CTX_new (TLSv1_method ()); + if (!ctx) + msg (M_SSLERR, "Cannot create SSL_CTX object"); + + ssl = SSL_new (ctx); + if (!ssl) + msg (M_SSLERR, "Cannot create SSL object"); + + printf ("Available TLS Ciphers,\n"); + printf ("listed in order of preference:\n\n"); + while ((cipher_name = SSL_get_cipher_list (ssl, priority++))) + printf ("%s\n", cipher_name); + printf ("\n"); + + SSL_free (ssl); + SSL_CTX_free (ctx); +} + +void +get_highest_preference_tls_cipher (char *buf, int size) +{ + SSL_CTX *ctx; + SSL *ssl; + const char *cipher_name; + + ctx = SSL_CTX_new (TLSv1_method ()); + if (!ctx) + msg (M_SSLERR, "Cannot create SSL_CTX object"); + ssl = SSL_new (ctx); + if (!ssl) + msg (M_SSLERR, "Cannot create SSL object"); + + cipher_name = SSL_get_cipher_list (ssl, 0); + strncpynt (buf, cipher_name, size); + + SSL_free (ssl); + SSL_CTX_free (ctx); +} + +#endif /* defined(ENABLE_SSL) && defined(ENABLE_CRYPTO_OPENSSL) */ |