diff options
Diffstat (limited to 'src/openvpn/ssl.c')
| -rw-r--r-- | src/openvpn/ssl.c | 4099 |
1 files changed, 0 insertions, 4099 deletions
diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c deleted file mode 100644 index 9cde47d..0000000 --- a/src/openvpn/ssl.c +++ /dev/null @@ -1,4099 +0,0 @@ -/* - * 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) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net> - * - * 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 - */ - -/* - * The routines in this file deal with dynamically negotiating - * the data channel HMAC and cipher keys through a TLS session. - * - * Both the TLS session and the data channel are multiplexed - * over the same TCP/UDP port. - */ - -#ifdef WIN32 -#include "config-win32.h" -#else -#include "config.h" -#endif - -#if defined(USE_CRYPTO) && defined(USE_SSL) - -#include "syshead.h" - -#include "ssl.h" -#include "error.h" -#include "common.h" -#include "integer.h" -#include "socket.h" -#include "thread.h" -#include "misc.h" -#include "fdmisc.h" -#include "interval.h" -#include "perf.h" -#include "status.h" -#include "gremlin.h" - -#ifdef WIN32 -#include "cryptoapi.h" -#endif - -#include "memdbg.h" - -#ifndef ENABLE_OCC -static const char ssl_default_options_string[] = "V0 UNDEF"; -#endif - -static inline const char * -local_options_string (const struct tls_session *session) -{ -#ifdef ENABLE_OCC - return session->opt->local_options; -#else - return ssl_default_options_string; -#endif -} - -#ifdef MEASURE_TLS_HANDSHAKE_STATS - -static int tls_handshake_success; /* GLOBAL */ -static int tls_handshake_error; /* GLOBAL */ -static int tls_packets_generated; /* GLOBAL */ -static int tls_packets_sent; /* GLOBAL */ - -#define INCR_SENT ++tls_packets_sent -#define INCR_GENERATED ++tls_packets_generated -#define INCR_SUCCESS ++tls_handshake_success -#define INCR_ERROR ++tls_handshake_error - -void -show_tls_performance_stats(void) -{ - msg (D_TLS_DEBUG_LOW, "TLS Handshakes, success=%f%% (good=%d, bad=%d), retransmits=%f%%", - (double) tls_handshake_success / (tls_handshake_success + tls_handshake_error) * 100.0, - tls_handshake_success, tls_handshake_error, - (double) (tls_packets_sent - tls_packets_generated) / tls_packets_generated * 100.0); -} -#else - -#define INCR_SENT -#define INCR_GENERATED -#define INCR_SUCCESS -#define INCR_ERROR - -#endif - -#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 - -/* - * Max number of bytes we will add - * for data structures common to both - * data and control channel packets. - * (opcode only). - */ -void -tls_adjust_frame_parameters(struct frame *frame) -{ - frame_add_to_extra_frame (frame, 1); /* space for opcode */ -} - -/* - * Max number of bytes we will add - * to control channel packet. - */ -static void -tls_init_control_channel_frame_parameters(const struct frame *data_channel_frame, - struct frame *frame) -{ - /* - * frame->extra_frame is already initialized with tls_auth buffer requirements, - * if --tls-auth is enabled. - */ - - /* inherit link MTU and extra_link from data channel */ - frame->link_mtu = data_channel_frame->link_mtu; - frame->extra_link = data_channel_frame->extra_link; - - /* set extra_frame */ - tls_adjust_frame_parameters (frame); - reliable_ack_adjust_frame_parameters (frame, CONTROL_SEND_ACK_MAX); - frame_add_to_extra_frame (frame, SID_SIZE + sizeof (packet_id_type)); - - /* set dynamic link MTU to minimum value */ - frame_set_mtu_dynamic (frame, 0, SET_MTU_TUN); -} - -/* - * Allocate space in SSL objects - * in which to store a struct tls_session - * pointer back to parent. - */ - -static int mydata_index; /* GLOBAL */ - -static void -ssl_set_mydata_index () -{ - mydata_index = SSL_get_ex_new_index (0, "struct session *", NULL, NULL, NULL); - ASSERT (mydata_index >= 0); -} - -void -init_ssl_lib () -{ - SSL_library_init (); - SSL_load_error_strings (); - OpenSSL_add_all_algorithms (); - - init_crypto_lib(); - - /* - * If you build the OpenSSL library and OpenVPN with - * CRYPTO_MDEBUG, you will get a listing of OpenSSL - * memory leaks on program termination. - */ -#ifdef CRYPTO_MDEBUG - CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON); -#endif - - ssl_set_mydata_index (); -} - -void -free_ssl_lib () -{ -#ifdef CRYPTO_MDEBUG - FILE* fp = fopen ("sdlog", "w"); - ASSERT (fp); - CRYPTO_mem_leaks_fp (fp); - fclose (fp); -#endif - - uninit_crypto_lib (); - EVP_cleanup (); - ERR_free_strings (); -} - -/* - * OpenSSL library calls pem_password_callback if the - * private key is protected by a password. - */ - -static struct user_pass passbuf; /* GLOBAL */ - -void -pem_password_setup (const char *auth_file) -{ - if (!strlen (passbuf.password)) - get_user_pass (&passbuf, auth_file, true, UP_TYPE_PRIVATE_KEY, GET_USER_PASS_MANAGEMENT|GET_USER_PASS_SENSITIVE); -} - -int -pem_password_callback (char *buf, int size, int rwflag, void *u) -{ - if (buf) - { - /* prompt for password even if --askpass wasn't specified */ - pem_password_setup (NULL); - strncpynt (buf, passbuf.password, size); - purge_user_pass (&passbuf, false); - - return strlen (buf); - } - return 0; -} - -/* - * Auth username/password handling - */ - -static bool auth_user_pass_enabled; /* GLOBAL */ -static struct user_pass auth_user_pass; /* GLOBAL */ - -void -auth_user_pass_setup (const char *auth_file) -{ - auth_user_pass_enabled = true; - if (!auth_user_pass.defined) - get_user_pass (&auth_user_pass, auth_file, false, UP_TYPE_AUTH, GET_USER_PASS_MANAGEMENT|GET_USER_PASS_SENSITIVE); -} - -/* - * Disable password caching - */ -void -ssl_set_auth_nocache (void) -{ - passbuf.nocache = true; - auth_user_pass.nocache = true; -} - -/* - * Forget private key password AND auth-user-pass username/password. - */ -void -ssl_purge_auth (void) -{ -#if 1 /* JYFIXME -- todo: bad private key should trigger a signal, then this code can be included */ - purge_user_pass (&passbuf, true); -#endif - purge_user_pass (&auth_user_pass, true); -} - -/* - * 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); -} - -/* - * Extract a field from an X509 subject name. - * - * Example: - * - * /C=US/ST=CO/L=Denver/O=ORG/CN=Test-CA/Email=jim@yonan.net - * - * The common name is 'Test-CA' - */ -static void -extract_x509_field (const char *x509, const char *field_name, char *out, int size) -{ - char field_buf[256]; - struct buffer x509_buf; - - ASSERT (size > 0); - *out = '\0'; - buf_set_read (&x509_buf, (uint8_t *)x509, strlen (x509)); - while (buf_parse (&x509_buf, '/', field_buf, sizeof (field_buf))) - { - struct buffer component_buf; - char field_name_buf[64]; - char field_value_buf[256]; - buf_set_read (&component_buf, (const uint8_t *) field_buf, strlen (field_buf)); - buf_parse (&component_buf, '=', field_name_buf, sizeof (field_name_buf)); - buf_parse (&component_buf, '=', field_value_buf, sizeof (field_value_buf)); - if (!strcmp (field_name_buf, field_name)) - { - strncpynt (out, field_value_buf, size); - break; - } - } -} - -static void -setenv_untrusted (struct tls_session *session) -{ - setenv_sockaddr (session->opt->es, "untrusted", &session->untrusted_sockaddr, SA_IP_PORT); -} - -static void -set_common_name (struct tls_session *session, const char *common_name) -{ - if (session->common_name) - { - free (session->common_name); - session->common_name = NULL; - } - if (common_name) - { - session->common_name = string_alloc (common_name, NULL); - } -} - -/* - * nsCertType checking - */ - -#define verify_nsCertType(x, usage) (((x)->ex_flags & EXFLAG_NSCERT) && ((x)->ex_nscert & (usage))) - -static const char * -print_nsCertType (int type) -{ - switch (type) - { - case NS_SSL_SERVER: - return "SERVER"; - case NS_SSL_CLIENT: - return "CLIENT"; - default: - return "?"; - } -} - -/* - * Our verify callback function -- check - * that an incoming peer certificate is good. - */ - -static int -verify_callback (int preverify_ok, X509_STORE_CTX * ctx) -{ - char subject[256]; - char envname[64]; - char common_name[TLS_CN_LEN]; - SSL *ssl; - struct tls_session *session; - const struct tls_options *opt; - const int max_depth = 8; - - /* get the tls_session pointer */ - ssl = X509_STORE_CTX_get_ex_data (ctx, SSL_get_ex_data_X509_STORE_CTX_idx()); - ASSERT (ssl); - session = (struct tls_session *) SSL_get_ex_data (ssl, mydata_index); - ASSERT (session); - opt = session->opt; - ASSERT (opt); - - session->verified = false; - - /* get the X509 name */ - X509_NAME_oneline (X509_get_subject_name (ctx->current_cert), subject, - sizeof (subject)); - subject[sizeof (subject) - 1] = '\0'; - - /* enforce character class restrictions in X509 name */ - string_mod (subject, X509_NAME_CHAR_CLASS, 0, '_'); - - /* extract the common name */ - extract_x509_field (subject, "CN", common_name, TLS_CN_LEN); - string_mod (common_name, COMMON_NAME_CHAR_CLASS, 0, '_'); - -#if 0 /* print some debugging info */ - msg (D_LOW, "LOCAL OPT: %s", opt->local_options); - msg (D_LOW, "X509: %s", subject); -#endif - - /* did peer present cert which was signed our root cert? */ - if (!preverify_ok) - { - /* Remote site specified a certificate, but it's not correct */ - msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, error=%s: %s", - ctx->error_depth, X509_verify_cert_error_string (ctx->error), subject); - goto err; /* Reject connection */ - } - - /* warn if cert chain is too deep */ - if (ctx->error_depth >= max_depth) - msg (M_WARN, "TLS Warning: Convoluted certificate chain detected with depth [%d] greater than %d", ctx->error_depth, max_depth); - - /* save common name in session object */ - if (ctx->error_depth == 0) - set_common_name (session, common_name); - - /* export subject name string as environmental variable */ - session->verify_maxlevel = max_int (session->verify_maxlevel, ctx->error_depth); - openvpn_snprintf (envname, sizeof(envname), "tls_id_%d", ctx->error_depth); - setenv_str (opt->es, envname, subject); - -#if 0 - /* export common name string as environmental variable */ - openvpn_snprintf (envname, sizeof(envname), "tls_common_name_%d", ctx->error_depth); - setenv_str (opt->es, envname, common_name); -#endif - - /* export serial number as environmental variable */ - { - const int serial = (int) ASN1_INTEGER_get (X509_get_serialNumber (ctx->current_cert)); - openvpn_snprintf (envname, sizeof(envname), "tls_serial_%d", ctx->error_depth); - setenv_int (opt->es, envname, serial); - } - - /* export current untrusted IP */ - setenv_untrusted (session); - - /* verify certificate nsCertType */ - if (opt->ns_cert_type && ctx->error_depth == 0) - { - if (verify_nsCertType (ctx->current_cert, opt->ns_cert_type)) - { - msg (D_HANDSHAKE, "VERIFY OK: nsCertType=%s", - print_nsCertType (opt->ns_cert_type)); - } - else - { - msg (D_HANDSHAKE, "VERIFY nsCertType ERROR: %s, require nsCertType=%s", - subject, print_nsCertType (opt->ns_cert_type)); - goto err; /* Reject connection */ - } - } - - /* verify X509 name or common name against --tls-remote */ - if (opt->verify_x509name && strlen (opt->verify_x509name) > 0 && ctx->error_depth == 0) - { - if (strcmp (opt->verify_x509name, subject) == 0 - || strncmp (opt->verify_x509name, common_name, strlen (opt->verify_x509name)) == 0) - msg (D_HANDSHAKE, "VERIFY X509NAME OK: %s", subject); - else - { - msg (D_HANDSHAKE, "VERIFY X509NAME ERROR: %s, must be %s", - subject, opt->verify_x509name); - goto err; /* Reject connection */ - } - } - - /* call --tls-verify plug-in(s) */ - if (plugin_defined (opt->plugins, OPENVPN_PLUGIN_TLS_VERIFY)) - { - char command[256]; - struct buffer out; - int ret; - - buf_set_write (&out, (uint8_t*)command, sizeof (command)); - buf_printf (&out, "%d %s", - ctx->error_depth, - subject); - - ret = plugin_call (opt->plugins, OPENVPN_PLUGIN_TLS_VERIFY, command, opt->es); - - if (!ret) - { - msg (D_HANDSHAKE, "VERIFY PLUGIN OK: depth=%d, %s", - ctx->error_depth, subject); - } - else - { - msg (D_HANDSHAKE, "VERIFY PLUGIN ERROR: depth=%d, %s", - ctx->error_depth, subject); - goto err; /* Reject connection */ - } - } - - /* run --tls-verify script */ - if (opt->verify_command) - { - char command[256]; - struct buffer out; - int ret; - - setenv_str (opt->es, "script_type", "tls-verify"); - - buf_set_write (&out, (uint8_t*)command, sizeof (command)); - buf_printf (&out, "%s %d %s", - opt->verify_command, - ctx->error_depth, - subject); - dmsg (D_TLS_DEBUG, "TLS: executing verify command: %s", command); - ret = openvpn_system (command, opt->es, S_SCRIPT); - - if (system_ok (ret)) - { - msg (D_HANDSHAKE, "VERIFY SCRIPT OK: depth=%d, %s", - ctx->error_depth, subject); - } - else - { - if (!system_executed (ret)) - msg (M_ERR, "Verify command failed to execute: %s", command); - msg (D_HANDSHAKE, "VERIFY SCRIPT ERROR: depth=%d, %s", - ctx->error_depth, subject); - goto err; /* Reject connection */ - } - } - - /* check peer cert against CRL */ - if (opt->crl_file) - { - X509_CRL *crl=NULL; - X509_REVOKED *revoked; - BIO *in=NULL; - int n,i,retval = 0; - - in=BIO_new(BIO_s_file()); - - if (in == NULL) { - msg (M_ERR, "CRL: BIO err"); - goto end; - } - if (BIO_read_filename(in, opt->crl_file) <= 0) { - msg (M_ERR, "CRL: cannot read: %s", opt->crl_file); - goto end; - } - crl=PEM_read_bio_X509_CRL(in,NULL,NULL,NULL); - if (crl == NULL) { - msg (M_ERR, "CRL: cannot read CRL from file %s", opt->crl_file); - goto end; - } - - if (X509_NAME_cmp(X509_CRL_get_issuer(crl), X509_get_issuer_name(ctx->current_cert)) != 0) { - msg (M_WARN, "CRL: CRL %s is from a different issuer than the issuer of certificate %s", opt->crl_file, subject); - retval = 1; - goto end; - } - - n = sk_num(X509_CRL_get_REVOKED(crl)); - - for (i = 0; i < n; i++) { - revoked = (X509_REVOKED *)sk_value(X509_CRL_get_REVOKED(crl), i); - if (ASN1_INTEGER_cmp(revoked->serialNumber, X509_get_serialNumber(ctx->current_cert)) == 0) { - msg (D_HANDSHAKE, "CRL CHECK FAILED: %s is REVOKED",subject); - goto end; - } - } - - retval = 1; - msg (D_HANDSHAKE, "CRL CHECK OK: %s",subject); - - end: - - BIO_free(in); - if (crl) - X509_CRL_free (crl); - if (!retval) - goto err; - } - - msg (D_HANDSHAKE, "VERIFY OK: depth=%d, %s", ctx->error_depth, subject); - - session->verified = true; - return 1; /* Accept connection */ - - err: - ERR_clear_error (); - return 0; /* Reject connection */ -} - -void -tls_set_common_name (struct tls_multi *multi, const char *common_name) -{ - if (multi) - set_common_name (&multi->session[TM_ACTIVE], common_name); -} - -const char * -tls_common_name (struct tls_multi *multi, bool null) -{ - const char *ret = NULL; - if (multi) - ret = multi->session[TM_ACTIVE].common_name; - if (ret && strlen (ret)) - return ret; - else if (null) - return NULL; - else - return "UNDEF"; -} - -void -tls_lock_common_name (struct tls_multi *multi) -{ - const char *cn = multi->session[TM_ACTIVE].common_name; - if (cn && !multi->locked_cn) - multi->locked_cn = string_alloc (cn, NULL); -} - -/* - * Return true if at least one valid key state exists - * which has passed authentication. If we are using - * username/password authentication, and the authentication - * failed, we may have a live S_ACTIVE/S_NORMAL key state - * even though the 'authenticated' var might be false. - * - * This is so that we can return an AUTH_FAILED error - * message to the client over the TLS channel. - * - * If 'authenticated' is false, tunnel traffic forwarding - * is disabled but TLS channel data can still be sent - * or received. - */ -bool -tls_authenticated (struct tls_multi *multi) -{ - if (multi) - { - int i; - for (i = 0; i < KEY_SCAN_SIZE; ++i) - { - const struct key_state *ks = multi->key_scan[i]; - if (DECRYPT_KEY_ENABLED (multi, ks) && ks->authenticated) - return true; - } - } - return false; -} - -void -tls_deauthenticate (struct tls_multi *multi) -{ - if (multi) - { - int i, j; - for (i = 0; i < TM_SIZE; ++i) - for (j = 0; j < KS_SIZE; ++j) - multi->session[i].key[j].authenticated = false; - } -} - -/* - * Print debugging information on SSL/TLS session negotiation. - */ -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)); - } -} - -/* - * Initialize SSL context. - * All files are in PEM format. - */ -SSL_CTX * -init_ssl (const struct options *options) -{ - SSL_CTX *ctx = NULL; - DH *dh; - BIO *bio; - bool using_cert_file = false; - - ERR_clear_error (); - - if (options->tls_server) - { - ctx = SSL_CTX_new (TLSv1_server_method ()); - if (ctx == NULL) - msg (M_SSLERR, "SSL_CTX_new TLSv1_server_method"); - - SSL_CTX_set_tmp_rsa_callback (ctx, tmp_rsa_cb); - - /* Get Diffie Hellman Parameters */ - if (!(bio = BIO_new_file (options->dh_file, "r"))) - msg (M_SSLERR, "Cannot open %s for DH parameters", options->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", options->dh_file); - if (!SSL_CTX_set_tmp_dh (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); - } - else /* if client */ - { - ctx = SSL_CTX_new (TLSv1_client_method ()); - if (ctx == NULL) - msg (M_SSLERR, "SSL_CTX_new TLSv1_client_method"); - } - - /* Set SSL options */ - SSL_CTX_set_session_cache_mode (ctx, SSL_SESS_CACHE_OFF); - SSL_CTX_set_options (ctx, SSL_OP_SINGLE_DH_USE); - - /* Set callback for getting password from user to decrypt private key */ - SSL_CTX_set_default_passwd_cb (ctx, pem_password_callback); - - if (options->pkcs12_file) - { - /* Use PKCS #12 file for key, cert and CA certs */ - - FILE *fp; - EVP_PKEY *pkey; - X509 *cert; - STACK_OF(X509) *ca = NULL; - PKCS12 *p12; - int i; - char password[256]; - - /* Load the PKCS #12 file */ - if (!(fp = fopen(options->pkcs12_file, "rb"))) - msg (M_SSLERR, "Error opening file %s", options->pkcs12_file); - p12 = d2i_PKCS12_fp(fp, NULL); - fclose (fp); - if (!p12) msg (M_SSLERR, "Error reading PKCS#12 file %s", options->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)) - { - PKCS12_free(p12); - msg (M_WARN|M_SSL, "Error parsing PKCS#12 file %s", options->pkcs12_file); - goto err; - } - } - PKCS12_free(p12); - - /* Load Certificate */ - if (!SSL_CTX_use_certificate (ctx, cert)) - msg (M_SSLERR, "Cannot use certificate"); - - /* Load Private Key */ - if (!SSL_CTX_use_PrivateKey (ctx, pkey)) - msg (M_SSLERR, "Cannot use private key"); - warn_if_group_others_accessible (options->pkcs12_file); - - /* Check Private Key */ - if (!SSL_CTX_check_private_key (ctx)) - msg (M_SSLERR, "Private key does not match the certificate"); - - /* Set Certificate Verification chain */ - if (ca && sk_num(ca)) - { - for (i = 0; i < sk_X509_num(ca); i++) - { - if (!X509_STORE_add_cert(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, sk_X509_value(ca, i))) - msg (M_SSLERR, "Cannot add certificate to client CA list (SSL_CTX_add_client_CA)"); - } - } - } - else - { - /* Use seperate PEM files for key, cert and CA certs */ - -#ifdef WIN32 - if (options->cryptoapi_cert) - { - /* Load Certificate and Private Key */ - if (!SSL_CTX_use_CryptoAPI_certificate (ctx, options->cryptoapi_cert)) - msg (M_SSLERR, "Cannot load certificate \"%s\" from Microsoft Certificate Store", - options->cryptoapi_cert); - } - else -#endif - { - /* Load Certificate */ - if (options->cert_file) - { - using_cert_file = true; - if (!SSL_CTX_use_certificate_file (ctx, options->cert_file, SSL_FILETYPE_PEM)) - msg (M_SSLERR, "Cannot load certificate file %s", options->cert_file); - } - - /* Load Private Key */ - if (options->priv_key_file) - { - if (!SSL_CTX_use_PrivateKey_file (ctx, options->priv_key_file, SSL_FILETYPE_PEM)) - { -#ifdef ENABLE_MANAGEMENT - if (management && (ERR_GET_REASON (ERR_peek_error()) == EVP_R_BAD_DECRYPT)) - management_auth_failure (management, UP_TYPE_PRIVATE_KEY); -#endif - msg (M_WARN|M_SSL, "Cannot load private key file %s", options->priv_key_file); - goto err; - } - warn_if_group_others_accessible (options->priv_key_file); - - /* Check Private Key */ - if (!SSL_CTX_check_private_key (ctx)) - msg (M_SSLERR, "Private key does not match the certificate"); - } - } - - /* Load CA file for verifying peer supplied certificate */ - ASSERT (options->ca_file); - if (!SSL_CTX_load_verify_locations (ctx, options->ca_file, NULL)) - msg (M_SSLERR, "Cannot load CA certificate file %s (SSL_CTX_load_verify_locations)", options->ca_file); - - /* Load names of CAs from file and use it as a client CA list */ - { - STACK_OF(X509_NAME) *cert_names; - cert_names = SSL_load_client_CA_file (options->ca_file); - if (!cert_names) - msg (M_SSLERR, "Cannot load CA certificate file %s (SSL_load_client_CA_file)", options->ca_file); - SSL_CTX_set_client_CA_list (ctx, cert_names); - } - - } - - /* Enable the use of certificate chains */ - if (using_cert_file) - { - if (!SSL_CTX_use_certificate_chain_file (ctx, options->cert_file)) - msg (M_SSLERR, "Cannot load certificate chain file %s (SSL_use_certificate_chain_file)", options->cert_file); - } - - /* Require peer certificate verification */ -#if P2MP_SERVER - if (options->client_cert_not_required) - { - msg (M_WARN, "WARNING: This configuration may accept clients which do not present a certificate"); - } - else -#endif - SSL_CTX_set_verify (ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, - verify_callback); - - /* Connection information callback */ - SSL_CTX_set_info_callback (ctx, info_callback); - - /* Allowable ciphers */ - if (options->cipher_list) - { - if (!SSL_CTX_set_cipher_list (ctx, options->cipher_list)) - msg (M_SSLERR, "Problem with cipher list: %s", options->cipher_list); - } - - ERR_clear_error (); - - return ctx; - - err: - ERR_clear_error (); - if (ctx) - SSL_CTX_free (ctx); - return NULL; -} - -/* - * Print a one line summary of SSL/TLS session handshake. - */ -static void -print_details (SSL * c_ssl, const char *prefix) -{ - SSL_CIPHER *ciph; - X509 *cert; - char s1[256]; - char s2[256]; - - s1[0] = s2[0] = 0; - ciph = SSL_get_current_cipher (c_ssl); - openvpn_snprintf (s1, sizeof (s1), "%s %s, cipher %s %s", - prefix, - SSL_get_version (c_ssl), - SSL_CIPHER_get_version (ciph), - SSL_CIPHER_get_name (ciph)); - cert = SSL_get_peer_certificate (c_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); -} - -/* - * Show the TLS ciphers that are available for us to use - * in the OpenSSL library. - */ -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); -} - -/* - * The OpenSSL library has a notion of preference in TLS - * ciphers. Higher preference == more secure. - * Return the highest preference cipher. - */ -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); -} - -/* - * Map internal constants to ascii names. - */ -static const char * -state_name (int state) -{ - switch (state) - { - case S_UNDEF: - return "S_UNDEF"; - case S_INITIAL: - return "S_INITIAL"; - case S_PRE_START: - return "S_PRE_START"; - case S_START: - return "S_START"; - case S_SENT_KEY: - return "S_SENT_KEY"; - case S_GOT_KEY: - return "S_GOT_KEY"; - case S_ACTIVE: - return "S_ACTIVE"; - case S_NORMAL: - return "S_NORMAL"; - case S_ERROR: - return "S_ERROR"; - default: - return "S_???"; - } -} - -static const char * -packet_opcode_name (int op) -{ - switch (op) - { - case P_CONTROL_HARD_RESET_CLIENT_V1: - return "P_CONTROL_HARD_RESET_CLIENT_V1"; - case P_CONTROL_HARD_RESET_SERVER_V1: - return "P_CONTROL_HARD_RESET_SERVER_V1"; - case P_CONTROL_HARD_RESET_CLIENT_V2: - return "P_CONTROL_HARD_RESET_CLIENT_V2"; - case P_CONTROL_HARD_RESET_SERVER_V2: - return "P_CONTROL_HARD_RESET_SERVER_V2"; - case P_CONTROL_SOFT_RESET_V1: - return "P_CONTROL_SOFT_RESET_V1"; - case P_CONTROL_V1: - return "P_CONTROL_V1"; - case P_ACK_V1: - return "P_ACK_V1"; - case P_DATA_V1: - return "P_DATA_V1"; - default: - return "P_???"; - } -} - -static const char * -session_index_name (int index) -{ - switch (index) - { - case TM_ACTIVE: - return "TM_ACTIVE"; - case TM_UNTRUSTED: - return "TM_UNTRUSTED"; - case TM_LAME_DUCK: - return "TM_LAME_DUCK"; - default: - return "TM_???"; - } -} - -/* - * For debugging. - */ -static const char * -print_key_id (struct tls_multi *multi, struct gc_arena *gc) -{ - int i; - struct buffer out = alloc_buf_gc (256, gc); - - for (i = 0; i < KEY_SCAN_SIZE; ++i) - { - struct key_state *ks = multi->key_scan[i]; - buf_printf (&out, " [key#%d state=%s id=%d sid=%s]", i, - state_name (ks->state), ks->key_id, - session_id_print (&ks->session_id_remote, gc)); - } - - return BSTR (&out); -} - -/* - * Given a key_method, return true if op - * represents the required form of hard_reset. - * - * If key_method = 0, return true if any - * form of hard reset is used. - */ -static bool -is_hard_reset (int op, int key_method) -{ - if (!key_method || key_method == 1) - if (op == P_CONTROL_HARD_RESET_CLIENT_V1 || op == P_CONTROL_HARD_RESET_SERVER_V1) - return true; - - if (!key_method || key_method >= 2) - if (op == P_CONTROL_HARD_RESET_CLIENT_V2 || op == P_CONTROL_HARD_RESET_SERVER_V2) - return true; - - return false; -} - -/* - * 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 (struct tls_multi* multi, 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; -} - -/* - * Read from an OpenSSL BIO in non-blocking mode. - */ -static int -bio_read (struct tls_multi* multi, 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; -} - -/* - * 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; - } -} - -static int -key_state_write_plaintext (struct tls_multi *multi, struct key_state *ks, struct buffer *buf) -{ - int ret; - perf_push (PERF_BIO_WRITE_PLAINTEXT); - ret = bio_write (multi, ks->ssl_bio, BPTR(buf), BLEN(buf), "tls_write_plaintext"); - bio_write_post (ret, buf); - perf_pop (); - return ret; -} - -static int -key_state_write_plaintext_const (struct tls_multi *multi, struct key_state *ks, const uint8_t *data, int len) -{ - int ret; - perf_push (PERF_BIO_WRITE_PLAINTEXT); - ret = bio_write (multi, ks->ssl_bio, data, len, "tls_write_plaintext_const"); - perf_pop (); - return ret; -} - -static int -key_state_write_ciphertext (struct tls_multi *multi, struct key_state *ks, struct buffer *buf) -{ - int ret; - perf_push (PERF_BIO_WRITE_CIPHERTEXT); - ret = bio_write (multi, ks->ct_in, BPTR(buf), BLEN(buf), "tls_write_ciphertext"); - bio_write_post (ret, buf); - perf_pop (); - return ret; -} - -static int -key_state_read_plaintext (struct tls_multi *multi, struct key_state *ks, struct buffer *buf, - int maxlen) -{ - int ret; - perf_push (PERF_BIO_READ_PLAINTEXT); - ret = bio_read (multi, ks->ssl_bio, buf, maxlen, "tls_read_plaintext"); - perf_pop (); - return ret; -} - -static int -key_state_read_ciphertext (struct tls_multi *multi, struct key_state *ks, struct buffer *buf, - int maxlen) -{ - int ret; - perf_push (PERF_BIO_READ_CIPHERTEXT); - ret = bio_read (multi, ks->ct_out, buf, maxlen, "tls_read_ciphertext"); - perf_pop (); - return ret; -} - -/* - * Initialize a key_state. Each key_state corresponds to - * a specific SSL/TLS session. - */ -static void -key_state_init (struct tls_session *session, struct key_state *ks) -{ - update_time (); - - /* - * Build TLS object that reads/writes ciphertext - * to/from memory BIOs. - */ - CLEAR (*ks); - - ks->ssl = SSL_new (session->opt->ssl_ctx); - if (!ks->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, mydata_index, session); - - ks->ssl_bio = getbio (BIO_f_ssl (), "ssl_bio"); - ks->ct_in = getbio (BIO_s_mem (), "ct_in"); - ks->ct_out = getbio (BIO_s_mem (), "ct_out"); - -#ifdef BIO_DEBUG - bio_debug_oc ("open ssl_bio", ks->ssl_bio); - bio_debug_oc ("open ct_in", ks->ct_in); - bio_debug_oc ("open ct_out", ks->ct_out); -#endif - - if (session->opt->server) - SSL_set_accept_state (ks->ssl); - else - SSL_set_connect_state (ks->ssl); - - SSL_set_bio (ks->ssl, ks->ct_in, ks->ct_out); - BIO_set_ssl (ks->ssl_bio, ks->ssl, BIO_NOCLOSE); - - /* Set control-channel initiation mode */ - ks->initial_opcode = session->initial_opcode; - session->initial_opcode = P_CONTROL_SOFT_RESET_V1; - ks->state = S_INITIAL; - ks->key_id = session->key_id; - - /* - * key_id increments to KEY_ID_MASK then recycles back to 1. - * This way you know that if key_id is 0, it is the first key. - */ - ++session->key_id; - session->key_id &= P_KEY_ID_MASK; - if (!session->key_id) - session->key_id = 1; - - /* allocate key source material object */ - ALLOC_OBJ_CLEAR (ks->key_src, struct key_source2); - - /* allocate reliability objects */ - ALLOC_OBJ_CLEAR (ks->send_reliable, struct reliable); - ALLOC_OBJ_CLEAR (ks->rec_reliable, struct reliable); - ALLOC_OBJ_CLEAR (ks->rec_ack, struct reliable_ack); - - /* allocate buffers */ - ks->plaintext_read_buf = alloc_buf (PLAINTEXT_BUFFER_SIZE); - ks->plaintext_write_buf = alloc_buf (PLAINTEXT_BUFFER_SIZE); - ks->ack_write_buf = alloc_buf (BUF_SIZE (&session->opt->frame)); - reliable_init (ks->send_reliable, BUF_SIZE (&session->opt->frame), - FRAME_HEADROOM (&session->opt->frame), TLS_RELIABLE_N_SEND_BUFFERS); - reliable_init (ks->rec_reliable, BUF_SIZE (&session->opt->frame), - FRAME_HEADROOM (&session->opt->frame), TLS_RELIABLE_N_REC_BUFFERS); - reliable_set_timeout (ks->send_reliable, session->opt->packet_timeout); - - /* init packet ID tracker */ - packet_id_init (&ks->packet_id, - session->opt->replay_window, - session->opt->replay_time); -} - -static void -key_state_free (struct key_state *ks, bool clear) -{ - ks->state = S_UNDEF; - - if (ks->ssl) { -#ifdef BIO_DEBUG - bio_debug_oc ("close ssl_bio", ks->ssl_bio); - bio_debug_oc ("close ct_in", ks->ct_in); - bio_debug_oc ("close ct_out", ks->ct_out); -#endif - BIO_free_all(ks->ssl_bio); - SSL_free (ks->ssl); - } - - free_key_ctx_bi (&ks->key); - free_buf (&ks->plaintext_read_buf); - free_buf (&ks->plaintext_write_buf); - free_buf (&ks->ack_write_buf); - - if (ks->send_reliable) - { - reliable_free (ks->send_reliable); - free (ks->send_reliable); - } - - if (ks->rec_reliable) - { - reliable_free (ks->rec_reliable); - free (ks->rec_reliable); - } - - if (ks->rec_ack) - free (ks->rec_ack); - - if (ks->key_src) - free (ks->key_src); - - packet_id_free (&ks->packet_id); - - if (clear) - CLEAR (*ks); -} - -/* - * Must be called if we move a tls_session in memory. - */ -static inline void tls_session_set_self_referential_pointers (struct tls_session* session) { - session->tls_auth.packet_id = &session->tls_auth_pid; -} - -/* - * Initialize a TLS session. A TLS session normally has 2 key_state objects, - * one for the current key, and one for the lame duck (i.e. retiring) key. - */ -static void -tls_session_init (struct tls_multi *multi, struct tls_session *session) -{ - struct gc_arena gc = gc_new (); - - dmsg (D_TLS_DEBUG, "TLS: tls_session_init: entry"); - - CLEAR (*session); - - /* Set options data to point to parent's option structure */ - session->opt = &multi->opt; - - /* Randomize session # if it is 0 */ - while (!session_id_defined(&session->session_id)) - session_id_random (&session->session_id); - - /* Are we a TLS server or client? */ - ASSERT (session->opt->key_method >= 1); - if (session->opt->key_method == 1) - { - session->initial_opcode = session->opt->server ? - P_CONTROL_HARD_RESET_SERVER_V1 : P_CONTROL_HARD_RESET_CLIENT_V1; - } - else /* session->opt->key_method >= 2 */ - { - session->initial_opcode = session->opt->server ? - P_CONTROL_HARD_RESET_SERVER_V2 : P_CONTROL_HARD_RESET_CLIENT_V2; - } - - /* Initialize control channel authentication parameters */ - session->tls_auth = session->opt->tls_auth; - - /* Set session internal pointers (also called if session object is moved in memory) */ - tls_session_set_self_referential_pointers (session); - - /* initialize packet ID replay window for --tls-auth */ - packet_id_init (session->tls_auth.packet_id, - session->opt->replay_window, - session->opt->replay_time); - - /* load most recent packet-id to replay protect on --tls-auth */ - packet_id_persist_load_obj (session->tls_auth.pid_persist, session->tls_auth.packet_id); - - key_state_init (session, &session->key[KS_PRIMARY]); - - dmsg (D_TLS_DEBUG, "TLS: tls_session_init: new session object, sid=%s", - session_id_print (&session->session_id, &gc)); - - gc_free (&gc); -} - -static void -tls_session_free (struct tls_session *session, bool clear) -{ - int i; - - if (session->tls_auth.packet_id) - packet_id_free (session->tls_auth.packet_id); - - for (i = 0; i < KS_SIZE; ++i) - key_state_free (&session->key[i], false); - - if (session->common_name) - free (session->common_name); - - if (clear) - CLEAR (*session); -} - -static void -move_session (struct tls_multi* multi, int dest, int src, bool reinit_src) -{ - msg (D_TLS_DEBUG_LOW, "TLS: move_session: dest=%s src=%s reinit_src=%d", - session_index_name(dest), - session_index_name(src), - reinit_src); - ASSERT (src != dest); - ASSERT (src >= 0 && src < TM_SIZE); - ASSERT (dest >= 0 && dest < TM_SIZE); - tls_session_free (&multi->session[dest], false); - multi->session[dest] = multi->session[src]; - tls_session_set_self_referential_pointers (&multi->session[dest]); - - if (reinit_src) - tls_session_init (multi, &multi->session[src]); - else - CLEAR (multi->session[src]); - - dmsg (D_TLS_DEBUG, "TLS: move_session: exit"); -} - -static void -reset_session (struct tls_multi *multi, struct tls_session *session) -{ - tls_session_free (session, false); - tls_session_init (multi, session); -} - -#if 0 -/* - * Transmit a TLS reset on our untrusted channel. - */ -static void -initiate_untrusted_session (struct tls_multi *multi, struct sockaddr_in *to) -{ - struct tls_session *session = &multi->session[TM_UNTRUSTED]; - struct key_state *ks = &session->key[KS_PRIMARY]; - - reset_session (multi, session); - ks->remote_addr = *to; - msg (D_TLS_DEBUG_LOW, "TLS: initiate_untrusted_session: addr=%s", print_sockaddr (to)); -} -#endif - -/* - * Used to determine in how many seconds we should be - * called again. - */ -static inline void -compute_earliest_wakeup (interval_t *earliest, interval_t seconds_from_now) { - if (seconds_from_now < *earliest) - *earliest = seconds_from_now; - if (*earliest < 0) - *earliest = 0; -} - -/* - * Return true if "lame duck" or retiring key has expired and can - * no longer be used. - */ -static inline bool -lame_duck_must_die (const struct tls_session* session, interval_t *wakeup) -{ - const struct key_state* lame = &session->key[KS_LAME_DUCK]; - if (lame->state >= S_INITIAL) - { - const time_t local_now = now; - ASSERT (lame->must_die); /* a lame duck key must always have an expiration */ - if (local_now < lame->must_die) - { - compute_earliest_wakeup (wakeup, lame->must_die - local_now); - return false; - } - else - return true; - } - else if (lame->state == S_ERROR) - return true; - else - return false; -} - -/* - * A tls_multi object fully encapsulates OpenVPN's TLS state. - * See ssl.h for more comments. - */ -struct tls_multi * -tls_multi_init (struct tls_options *tls_options) -{ - struct tls_multi *ret; - - ALLOC_OBJ_CLEAR (ret, struct tls_multi); - - /* get command line derived options */ - ret->opt = *tls_options; - - /* set up pointer to HMAC object for TLS packet authentication */ - ret->opt.tls_auth.key_ctx_bi = &ret->opt.tls_auth_key; - - /* set up list of keys to be scanned by data channel encrypt and decrypt routines */ - ASSERT (SIZE (ret->key_scan) == 3); - ret->key_scan[0] = &ret->session[TM_ACTIVE].key[KS_PRIMARY]; - ret->key_scan[1] = &ret->session[TM_ACTIVE].key[KS_LAME_DUCK]; - ret->key_scan[2] = &ret->session[TM_LAME_DUCK].key[KS_LAME_DUCK]; - - return ret; -} - -/* - * Finalize our computation of frame sizes. - */ -void -tls_multi_init_finalize (struct tls_multi* multi, const struct frame* frame) -{ - tls_init_control_channel_frame_parameters (frame, &multi->opt.frame); - - /* initialize the active and untrusted sessions */ - - tls_session_init (multi, &multi->session[TM_ACTIVE]); - - if (!multi->opt.single_session) - tls_session_init (multi, &multi->session[TM_UNTRUSTED]); -} - -/* - * Initialize and finalize a standalone tls-auth verification object. - */ - -struct tls_auth_standalone * -tls_auth_standalone_init (struct tls_options *tls_options, - struct gc_arena *gc) -{ - struct tls_auth_standalone *tas; - - ALLOC_OBJ_CLEAR_GC (tas, struct tls_auth_standalone, gc); - - /* set up pointer to HMAC object for TLS packet authentication */ - tas->tls_auth_key = tls_options->tls_auth_key; - tas->tls_auth_options.key_ctx_bi = &tas->tls_auth_key; - tas->tls_auth_options.flags |= CO_PACKET_ID_LONG_FORM; - - /* get initial frame parms, still need to finalize */ - tas->frame = tls_options->frame; - - return tas; -} - -void -tls_auth_standalone_finalize (struct tls_auth_standalone *tas, - const struct frame *frame) -{ - tls_init_control_channel_frame_parameters (frame, &tas->frame); -} - -/* - * Set local and remote option compatibility strings. - * Used to verify compatibility of local and remote option - * sets. - */ -void -tls_multi_init_set_options (struct tls_multi* multi, - const char *local, - const char *remote) -{ -#ifdef ENABLE_OCC - /* initialize options string */ - multi->opt.local_options = local; - multi->opt.remote_options = remote; -#endif -} - -void -tls_multi_free (struct tls_multi *multi, bool clear) -{ - int i; - - ASSERT (multi); - - if (multi->locked_cn) - free (multi->locked_cn); - - for (i = 0; i < TM_SIZE; ++i) - tls_session_free (&multi->session[i], false); - - if (clear) - CLEAR (*multi); - - free(multi); -} - -/* - * Move a packet authentication HMAC + related fields to or from the front - * of the buffer so it can be processed by encrypt/decrypt. - */ - -/* - * Dependent on hmac size, opcode size, and session_id size. - * Will assert if too small. - */ -#define SWAP_BUF_SIZE 256 - -static bool -swap_hmac (struct buffer *buf, const struct crypto_options *co, bool incoming) -{ - struct key_ctx *ctx; - - ASSERT (co); - - ctx = (incoming ? &co->key_ctx_bi->decrypt : &co->key_ctx_bi->encrypt); - ASSERT (ctx->hmac); - - { - /* hmac + packet_id (8 bytes) */ - const int hmac_size = HMAC_size (ctx->hmac) + packet_id_size (true); - - /* opcode + session_id */ - const int osid_size = 1 + SID_SIZE; - - int e1, e2; - uint8_t *b = BPTR (buf); - uint8_t buf1[SWAP_BUF_SIZE]; - uint8_t buf2[SWAP_BUF_SIZE]; - - if (incoming) - { - e1 = osid_size; - e2 = hmac_size; - } - else - { - e1 = hmac_size; - e2 = osid_size; - } - - ASSERT (e1 <= SWAP_BUF_SIZE && e2 <= SWAP_BUF_SIZE); - - if (buf->len >= e1 + e2) - { - memcpy (buf1, b, e1); - memcpy (buf2, b + e1, e2); - memcpy (b, buf2, e2); - memcpy (b + e2, buf1, e1); - return true; - } - else - return false; - } -} - -#undef SWAP_BUF_SIZE - -/* - * Write a control channel authentication record. - */ -static void -write_control_auth (struct tls_session *session, - struct key_state *ks, - struct buffer *buf, - struct sockaddr_in *to_link_addr, - int opcode, - int max_ack, - bool prepend_ack) -{ - uint8_t *header; - struct buffer null = clear_buf (); - - ASSERT (addr_defined (&ks->remote_addr)); - ASSERT (reliable_ack_write - (ks->rec_ack, buf, &ks->session_id_remote, max_ack, prepend_ack)); - ASSERT (session_id_write_prepend (&session->session_id, buf)); - ASSERT (header = buf_prepend (buf, 1)); - *header = ks->key_id | (opcode << P_OPCODE_SHIFT); - if (session->tls_auth.key_ctx_bi->encrypt.hmac) - { - /* no encryption, only write hmac */ - openvpn_encrypt (buf, null, &session->tls_auth, NULL); - ASSERT (swap_hmac (buf, &session->tls_auth, false)); - } - *to_link_addr = ks->remote_addr; -} - -/* - * Read a control channel authentication record. - */ -static bool -read_control_auth (struct buffer *buf, - const struct crypto_options *co, - const struct sockaddr_in *from) -{ - struct gc_arena gc = gc_new (); - - if (co->key_ctx_bi->decrypt.hmac) - { - struct buffer null = clear_buf (); - - /* move the hmac record to the front of the packet */ - if (!swap_hmac (buf, co, true)) - { - msg (D_TLS_ERRORS, - "TLS Error: cannot locate HMAC in incoming packet from %s", - print_sockaddr (from, &gc)); - gc_free (&gc); - return false; - } - - /* authenticate only (no decrypt) and remove the hmac record - from the head of the buffer */ - openvpn_decrypt (buf, null, co, NULL); - if (!buf->len) - { - msg (D_TLS_ERRORS, - "TLS Error: incoming packet authentication failed from %s", - print_sockaddr (from, &gc)); - gc_free (&gc); - return false; - } - - } - - /* advance buffer pointer past opcode & session_id since our caller - already read it */ - buf_advance (buf, SID_SIZE + 1); - - gc_free (&gc); - return true; -} - -/* - * For debugging, print contents of key_source2 structure. - */ - -static void -key_source_print (const struct key_source *k, - const char *prefix) -{ - struct gc_arena gc = gc_new (); - - VALGRIND_MAKE_READABLE ((void *)k->pre_master, sizeof (k->pre_master)); - VALGRIND_MAKE_READABLE ((void *)k->random1, sizeof (k->random1)); - VALGRIND_MAKE_READABLE ((void *)k->random2, sizeof (k->random2)); - - dmsg (D_SHOW_KEY_SOURCE, - "%s pre_master: %s", - prefix, - format_hex (k->pre_master, sizeof (k->pre_master), 0, &gc)); - dmsg (D_SHOW_KEY_SOURCE, - "%s random1: %s", - prefix, - format_hex (k->random1, sizeof (k->random1), 0, &gc)); - dmsg (D_SHOW_KEY_SOURCE, - "%s random2: %s", - prefix, - format_hex (k->random2, sizeof (k->random2), 0, &gc)); - - gc_free (&gc); -} - -static void -key_source2_print (const struct key_source2 *k) -{ - key_source_print (&k->client, "Client"); - key_source_print (&k->server, "Server"); -} - -/* - * Use the TLS PRF function for generating data channel keys. - * This code is taken from the OpenSSL library. - * - * TLS generates keys as such: - * - * master_secret[48] = PRF(pre_master_secret[48], "master secret", - * ClientHello.random[32] + ServerHello.random[32]) - * - * key_block[] = PRF(SecurityParameters.master_secret[48], - * "key expansion", - * SecurityParameters.server_random[32] + - * SecurityParameters.client_random[32]); - * - * Notes: - * - * (1) key_block contains a full set of 4 keys. - * (2) The pre-master secret is generated by the client. - */ - -static void -tls1_P_hash(const EVP_MD *md, - const uint8_t *sec, - int sec_len, - const uint8_t *seed, - int seed_len, - uint8_t *out, - int olen) -{ - struct gc_arena gc = gc_new (); - int chunk,n; - unsigned int j; - HMAC_CTX ctx; - HMAC_CTX ctx_tmp; - uint8_t A1[EVP_MAX_MD_SIZE]; - unsigned int A1_len; - -#ifdef ENABLE_DEBUG - const int olen_orig = olen; - const uint8_t *out_orig = out; -#endif - - dmsg (D_SHOW_KEY_SOURCE, "tls1_P_hash sec: %s", format_hex (sec, sec_len, 0, &gc)); - dmsg (D_SHOW_KEY_SOURCE, "tls1_P_hash seed: %s", format_hex (seed, seed_len, 0, &gc)); - - chunk=EVP_MD_size(md); - - HMAC_CTX_init(&ctx); - HMAC_CTX_init(&ctx_tmp); - HMAC_Init_ex(&ctx,sec,sec_len,md, NULL); - HMAC_Init_ex(&ctx_tmp,sec,sec_len,md, NULL); - HMAC_Update(&ctx,seed,seed_len); - HMAC_Final(&ctx,A1,&A1_len); - - n=0; - for (;;) - { - HMAC_Init_ex(&ctx,NULL,0,NULL,NULL); /* re-init */ - HMAC_Init_ex(&ctx_tmp,NULL,0,NULL,NULL); /* re-init */ - HMAC_Update(&ctx,A1,A1_len); - HMAC_Update(&ctx_tmp,A1,A1_len); - HMAC_Update(&ctx,seed,seed_len); - - if (olen > chunk) - { - HMAC_Final(&ctx,out,&j); - out+=j; - olen-=j; - HMAC_Final(&ctx_tmp,A1,&A1_len); /* calc the next A1 value */ - } - else /* last one */ - { - HMAC_Final(&ctx,A1,&A1_len); - memcpy(out,A1,olen); - break; - } - } - HMAC_CTX_cleanup(&ctx); - HMAC_CTX_cleanup(&ctx_tmp); - CLEAR (A1); - - dmsg (D_SHOW_KEY_SOURCE, "tls1_P_hash out: %s", format_hex (out_orig, olen_orig, 0, &gc)); - gc_free (&gc); -} - -static void -tls1_PRF(uint8_t *label, - int label_len, - const uint8_t *sec, - int slen, - uint8_t *out1, - int olen) -{ - struct gc_arena gc = gc_new (); - const EVP_MD *md5 = EVP_md5(); - const EVP_MD *sha1 = EVP_sha1(); - int len,i; - const uint8_t *S1,*S2; - uint8_t *out2; - - out2 = (uint8_t *) gc_malloc (olen, false, &gc); - - len=slen/2; - S1=sec; - S2= &(sec[len]); - len+=(slen&1); /* add for odd, make longer */ - - - tls1_P_hash(md5 ,S1,len,label,label_len,out1,olen); - tls1_P_hash(sha1,S2,len,label,label_len,out2,olen); - - for (i=0; i<olen; i++) - out1[i]^=out2[i]; - - memset (out2, 0, olen); - - dmsg (D_SHOW_KEY_SOURCE, "tls1_PRF out[%d]: %s", olen, format_hex (out1, olen, 0, &gc)); - - gc_free (&gc); -} - -static void -openvpn_PRF (const uint8_t *secret, - int secret_len, - const char *label, - const uint8_t *client_seed, - int client_seed_len, - const uint8_t *server_seed, - int server_seed_len, - const struct session_id *client_sid, - const struct session_id *server_sid, - uint8_t *output, - int output_len) -{ - /* concatenate seed components */ - - struct buffer seed = alloc_buf (strlen (label) - + client_seed_len - + server_seed_len - + SID_SIZE * 2); - - ASSERT (buf_write (&seed, label, strlen (label))); - ASSERT (buf_write (&seed, client_seed, client_seed_len)); - ASSERT (buf_write (&seed, server_seed, server_seed_len)); - - if (client_sid) - ASSERT (buf_write (&seed, client_sid->id, SID_SIZE)); - if (server_sid) - ASSERT (buf_write (&seed, server_sid->id, SID_SIZE)); - - /* compute PRF */ - tls1_PRF (BPTR(&seed), BLEN(&seed), secret, secret_len, output, output_len); - - buf_clear (&seed); - free_buf (&seed); - - VALGRIND_MAKE_READABLE ((void *)output, output_len); -} - -/* - * Using source entropy from local and remote hosts, mix into - * master key. - */ -static bool -generate_key_expansion (struct key_ctx_bi *key, - const struct key_type *key_type, - const struct key_source2 *key_src, - const struct session_id *client_sid, - const struct session_id *server_sid, - bool server) -{ - uint8_t master[48]; - struct key2 key2; - bool ret = false; - int i; - - CLEAR (master); - CLEAR (key2); - - /* debugging print of source key material */ - key_source2_print (key_src); - - /* compute master secret */ - openvpn_PRF (key_src->client.pre_master, - sizeof(key_src->client.pre_master), - KEY_EXPANSION_ID " master secret", - key_src->client.random1, - sizeof(key_src->client.random1), - key_src->server.random1, - sizeof(key_src->server.random1), - NULL, - NULL, - master, - sizeof(master)); - - /* compute key expansion */ - openvpn_PRF (master, - sizeof(master), - KEY_EXPANSION_ID " key expansion", - key_src->client.random2, - sizeof(key_src->client.random2), - key_src->server.random2, - sizeof(key_src->server.random2), - client_sid, - server_sid, - (uint8_t*)key2.keys, - sizeof(key2.keys)); - - key2.n = 2; - - key2_print (&key2, key_type, "Master Encrypt", "Master Decrypt"); - - /* check for weak keys */ - for (i = 0; i < 2; ++i) - { - fixup_key (&key2.keys[i], key_type); - if (!check_key (&key2.keys[i], key_type)) - { - msg (D_TLS_ERRORS, "TLS Error: Bad dynamic key generated"); - goto exit; - } - } - - /* Initialize OpenSSL key contexts */ - - ASSERT (server == true || server == false); - - init_key_ctx (&key->encrypt, - &key2.keys[(int)server], - key_type, - DO_ENCRYPT, - "Data Channel Encrypt"); - - init_key_ctx (&key->decrypt, - &key2.keys[1-(int)server], - key_type, - DO_DECRYPT, - "Data Channel Decrypt"); - - ret = true; - - exit: - CLEAR (master); - CLEAR (key2); - - return ret; -} - -static bool -random_bytes_to_buf (struct buffer *buf, - uint8_t *out, - int outlen) -{ - if (!RAND_bytes (out, outlen)) - msg (M_FATAL, "ERROR: Random number generator cannot obtain entropy for key generation [SSL]"); - if (!buf_write (buf, out, outlen)) - return false; - return true; -} - -static bool -key_source2_randomize_write (struct key_source2 *k2, - struct buffer *buf, - bool server) -{ - struct key_source *k = &k2->client; - if (server) - k = &k2->server; - - CLEAR (*k); - - if (!server) - { - if (!random_bytes_to_buf (buf, k->pre_master, sizeof (k->pre_master))) - return false; - } - - if (!random_bytes_to_buf (buf, k->random1, sizeof (k->random1))) - return false; - if (!random_bytes_to_buf (buf, k->random2, sizeof (k->random2))) - return false; - - return true; -} - -static int -key_source2_read (struct key_source2 *k2, - struct buffer *buf, - bool server) -{ - struct key_source *k = &k2->client; - - if (!server) - k = &k2->server; - - CLEAR (*k); - - if (server) - { - if (!buf_read (buf, k->pre_master, sizeof (k->pre_master))) - return 0; - } - - if (!buf_read (buf, k->random1, sizeof (k->random1))) - return 0; - if (!buf_read (buf, k->random2, sizeof (k->random2))) - return 0; - - return 1; -} - -/* - * Macros for key_state_soft_reset & tls_process - */ -#define ks (&session->key[KS_PRIMARY]) /* primary key */ -#define ks_lame (&session->key[KS_LAME_DUCK]) /* retiring key */ - -/* true if no in/out acknowledgements pending */ -#define FULL_SYNC \ - (reliable_empty(ks->send_reliable) && reliable_ack_empty (ks->rec_ack)) - -/* - * Move the active key to the lame duck key and reinitialize the - * active key. - */ -static void -key_state_soft_reset (struct tls_session *session) -{ - ks->must_die = now + session->opt->transition_window; /* remaining lifetime of old key */ - key_state_free (ks_lame, false); - *ks_lame = *ks; - - key_state_init (session, ks); - ks->session_id_remote = ks_lame->session_id_remote; - ks->remote_addr = ks_lame->remote_addr; -} - -/* - * Read/write strings from/to a struct buffer with a u16 length prefix. - */ - -static bool -write_string (struct buffer *buf, const char *str, const int maxlen) -{ - const int len = strlen (str) + 1; - if (len < 1 || (maxlen >= 0 && len > maxlen)) - return false; - if (!buf_write_u16 (buf, len)) - return false; - if (!buf_write (buf, str, len)) - return false; - return true; -} - -static bool -read_string (struct buffer *buf, char *str, const unsigned int capacity) -{ - const int len = buf_read_u16 (buf); - if (len < 1 || len > (int)capacity) - return false; - if (!buf_read (buf, str, len)) - return false; - str[len-1] = '\0'; - return true; -} - -/* - * Authenticate a client using username/password. - * Runs on server. - * - * If you want to add new authentication methods, - * this is the place to start. - */ - -static bool -verify_user_pass_script (struct tls_session *session, const struct user_pass *up) -{ - struct gc_arena gc = gc_new (); - struct buffer cmd = alloc_buf_gc (256, &gc); - const char *tmp_file = ""; - int retval; - bool ret = false; - - /* Is username defined? */ - if (strlen (up->username)) - { - /* Set environmental variables prior to calling script */ - setenv_str (session->opt->es, "script_type", "user-pass-verify"); - - if (session->opt->auth_user_pass_verify_script_via_file) - { - struct status_output *so; - - tmp_file = create_temp_filename (session->opt->tmp_dir, &gc); - so = status_open (tmp_file, 0, -1, NULL, STATUS_OUTPUT_WRITE); - status_printf (so, "%s", up->username); - status_printf (so, "%s", up->password); - if (!status_close (so)) - { - msg (D_TLS_ERRORS, "TLS Auth Error: could not write username/password to file: %s", - tmp_file); - goto done; - } - } - else - { - setenv_str (session->opt->es, "username", up->username); - setenv_str (session->opt->es, "password", up->password); - } - - /* setenv incoming cert common name for script */ - setenv_str (session->opt->es, "common_name", session->common_name); - - /* setenv client real IP address */ - setenv_untrusted (session); - - /* format command line */ - buf_printf (&cmd, "%s %s", session->opt->auth_user_pass_verify_script, tmp_file); - - /* call command */ - retval = openvpn_system (BSTR (&cmd), session->opt->es, S_SCRIPT); - - /* test return status of command */ - if (system_ok (retval)) - ret = true; - else if (!system_executed (retval)) - msg (D_TLS_ERRORS, "TLS Auth Error: user-pass-verify script failed to execute: %s", BSTR (&cmd)); - - if (!session->opt->auth_user_pass_verify_script_via_file) - setenv_del (session->opt->es, "password"); - } - else - { - msg (D_TLS_ERRORS, "TLS Auth Error: peer provided a blank username"); - } - - done: - if (strlen (tmp_file) > 0) - delete_file (tmp_file); - - gc_free (&gc); - return ret; -} - -static bool -verify_user_pass_plugin (struct tls_session *session, const struct user_pass *up, const char *raw_username) -{ - int retval; - bool ret = false; - - /* Is username defined? */ - if (strlen (up->username)) - { - /* set username/password in private env space */ - setenv_str (session->opt->es, "username", raw_username); - setenv_str (session->opt->es, "password", up->password); - - /* setenv incoming cert common name for script */ - setenv_str (session->opt->es, "common_name", session->common_name); - - /* setenv client real IP address */ - setenv_untrusted (session); - - /* call command */ - retval = plugin_call (session->opt->plugins, OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY, NULL, session->opt->es); - - if (!retval) - ret = true; - - setenv_del (session->opt->es, "password"); - setenv_str (session->opt->es, "username", up->username); - } - else - { - msg (D_TLS_ERRORS, "TLS Auth Error: peer provided a blank username"); - } - - return ret; -} - -/* - * Handle the reading and writing of key data to and from - * the TLS control channel (cleartext). - */ - -static bool -key_method_1_write (struct buffer *buf, struct tls_session *session) -{ - struct key key; - - ASSERT (session->opt->key_method == 1); - ASSERT (buf_init (buf, 0)); - - generate_key_random (&key, &session->opt->key_type); - if (!check_key (&key, &session->opt->key_type)) - { - msg (D_TLS_ERRORS, "TLS Error: Bad encrypting key generated"); - return false; - } - - if (!write_key (&key, &session->opt->key_type, buf)) - { - msg (D_TLS_ERRORS, "TLS Error: write_key failed"); - return false; - } - - init_key_ctx (&ks->key.encrypt, &key, &session->opt->key_type, - DO_ENCRYPT, "Data Channel Encrypt"); - CLEAR (key); - - /* send local options string */ - { - const char *local_options = local_options_string (session); - const int optlen = strlen (local_options) + 1; - if (!buf_write (buf, local_options, optlen)) - { - msg (D_TLS_ERRORS, "TLS Error: KM1 write options failed"); - return false; - } - } - - return true; -} - -static bool -key_method_2_write (struct buffer *buf, struct tls_session *session) -{ - ASSERT (session->opt->key_method == 2); - ASSERT (buf_init (buf, 0)); - - /* write a uint32 0 */ - if (!buf_write_u32 (buf, 0)) - goto error; - - /* write key_method + flags */ - if (!buf_write_u8 (buf, (session->opt->key_method & KEY_METHOD_MASK))) - goto error; - - /* write key source material */ - if (!key_source2_randomize_write (ks->key_src, buf, session->opt->server)) - goto error; - - /* write options string */ - { - if (!write_string (buf, local_options_string (session), TLS_OPTIONS_LEN)) - goto error; - } - - /* write username/password if specified */ - if (auth_user_pass_enabled) - { - auth_user_pass_setup (NULL); - if (!write_string (buf, auth_user_pass.username, -1)) - goto error; - if (!write_string (buf, auth_user_pass.password, -1)) - goto error; - purge_user_pass (&auth_user_pass, false); - } - - /* - * generate tunnel keys if server - */ - if (session->opt->server) - { - if (ks->authenticated) - { - if (!generate_key_expansion (&ks->key, - &session->opt->key_type, - ks->key_src, - &ks->session_id_remote, - &session->session_id, - true)) - { - msg (D_TLS_ERRORS, "TLS Error: server generate_key_expansion failed"); - goto error; - } - } - - CLEAR (*ks->key_src); - } - - return true; - - error: - msg (D_TLS_ERRORS, "TLS Error: Key Method #2 write failed"); - CLEAR (*ks->key_src); - return false; -} - -static bool -key_method_1_read (struct buffer *buf, struct tls_session *session) -{ - int status; - struct key key; - - ASSERT (session->opt->key_method == 1); - - if (!session->verified) - { - msg (D_TLS_ERRORS, - "TLS Error: Certificate verification failed (key-method 1)"); - goto error; - } - - status = read_key (&key, &session->opt->key_type, buf); - if (status != 1) - { - msg (D_TLS_ERRORS, - "TLS Error: Error reading data channel key from plaintext buffer"); - goto error; - } - - if (!check_key (&key, &session->opt->key_type)) - { - msg (D_TLS_ERRORS, "TLS Error: Bad decrypting key received from peer"); - goto error; - } - - if (buf->len < 1) - { - msg (D_TLS_ERRORS, "TLS Error: Missing options string"); - goto error; - } - -#ifdef ENABLE_OCC - /* compare received remote options string - with our locally computed options string */ - if (!session->opt->disable_occ && - !options_cmp_equal_safe ((char *) BPTR (buf), session->opt->remote_options, buf->len)) - { - options_warning_safe ((char *) BPTR (buf), session->opt->remote_options, buf->len); - } -#endif - - buf_clear (buf); - - init_key_ctx (&ks->key.decrypt, &key, &session->opt->key_type, - DO_DECRYPT, "Data Channel Decrypt"); - CLEAR (key); - ks->authenticated = true; - return true; - - error: - buf_clear (buf); - CLEAR (key); - return false; -} - -static bool -key_method_2_read (struct buffer *buf, struct tls_multi *multi, struct tls_session *session) -{ - struct gc_arena gc = gc_new (); - int key_method_flags; - char *options; - struct user_pass *up; - - ASSERT (session->opt->key_method == 2); - - /* allocate temporary objects */ - ALLOC_ARRAY_CLEAR_GC (options, char, TLS_OPTIONS_LEN, &gc); - - /* discard leading uint32 */ - ASSERT (buf_advance (buf, 4)); - - /* get key method */ - key_method_flags = buf_read_u8 (buf); - if ((key_method_flags & KEY_METHOD_MASK) != 2) - { - msg (D_TLS_ERRORS, - "TLS ERROR: Unknown key_method/flags=%d received from remote host", - key_method_flags); - goto error; - } - - /* get key source material (not actual keys yet) */ - if (!key_source2_read (ks->key_src, buf, session->opt->server)) - { - msg (D_TLS_ERRORS, "TLS Error: Error reading remote data channel key source entropy from plaintext buffer"); - goto error; - } - - /* get options */ - if (!read_string (buf, options, TLS_OPTIONS_LEN)) - { - msg (D_TLS_ERRORS, "TLS Error: Failed to read required OCC options string"); - goto error; - } - - /* should we check username/password? */ - ks->authenticated = false; - if (session->opt->auth_user_pass_verify_script - || plugin_defined (session->opt->plugins, OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY)) - { - bool s1 = true; - bool s2 = true; - char *raw_username; - - /* get username/password from plaintext buffer */ - ALLOC_OBJ_CLEAR_GC (up, struct user_pass, &gc); - if (!read_string (buf, up->username, USER_PASS_LEN) - || !read_string (buf, up->password, USER_PASS_LEN)) - { - msg (D_TLS_ERRORS, "TLS Error: Auth Username/Password was not provided by peer"); - CLEAR (*up); - goto error; - } - - /* preserve raw username before string_mod remapping, for plugins */ - ALLOC_ARRAY_CLEAR_GC (raw_username, char, USER_PASS_LEN, &gc); - strcpy (raw_username, up->username); - string_mod (raw_username, CC_PRINT, CC_CRLF, '_'); - - /* enforce character class restrictions in username/password */ - string_mod (up->username, COMMON_NAME_CHAR_CLASS, 0, '_'); - string_mod (up->password, CC_PRINT, CC_CRLF, '_'); - - /* call plugin(s) and/or script */ - if (plugin_defined (session->opt->plugins, OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY)) - s1 = verify_user_pass_plugin (session, up, raw_username); - if (session->opt->auth_user_pass_verify_script) - s2 = verify_user_pass_script (session, up); - - /* auth succeeded? */ - if (s1 && s2) - { - ks->authenticated = true; - if (session->opt->username_as_common_name) - set_common_name (session, up->username); - msg (D_HANDSHAKE, "TLS: Username/Password authentication succeeded for username '%s' %s", - up->username, - session->opt->username_as_common_name ? "[CN SET]" : ""); - } - else - { - msg (D_TLS_ERRORS, "TLS Auth Error: Auth Username/Password verification failed for peer"); - } - - CLEAR (*up); - } - else - { - if (!session->verified) - { - msg (D_TLS_ERRORS, - "TLS Error: Certificate verification failed (key-method 2)"); - goto error; - } - ks->authenticated = true; - } - - /* While it shouldn't really happen, don't allow the common name to be NULL */ - if (!session->common_name) - set_common_name (session, ""); - - /* Don't allow the CN to change once it's been locked */ - if (ks->authenticated && multi->locked_cn) - { - const char *cn = session->common_name; - if (cn && strcmp (cn, multi->locked_cn)) - { - msg (D_TLS_ERRORS, "TLS Auth Error: TLS object CN attempted to change from '%s' to '%s' -- tunnel disabled", - multi->locked_cn, - cn); - - /* change the common name back to its original value and disable the tunnel */ - set_common_name (session, multi->locked_cn); - tls_deauthenticate (multi); - } - } - - /* verify --client-config-dir based authentication */ - if (ks->authenticated && session->opt->client_config_dir_exclusive) - { - const char *cn = session->common_name; - const char *path = gen_path (session->opt->client_config_dir_exclusive, cn, &gc); - if (!cn || !strcmp (cn, CCD_DEFAULT) || !test_file (path)) - { - ks->authenticated = false; - msg (D_TLS_ERRORS, "TLS Auth Error: --client-config-dir authentication failed for common name '%s' file='%s'", - session->common_name, - path ? path : "UNDEF"); - } - } - -#ifdef ENABLE_OCC - /* check options consistency */ - if (!session->opt->disable_occ && - !options_cmp_equal (options, session->opt->remote_options)) - { - options_warning (options, session->opt->remote_options); - } -#endif - - buf_clear (buf); - - /* - * generate tunnel keys if client - */ - if (!session->opt->server) - { - if (!generate_key_expansion (&ks->key, - &session->opt->key_type, - ks->key_src, - &session->session_id, - &ks->session_id_remote, - false)) - { - msg (D_TLS_ERRORS, "TLS Error: client generate_key_expansion failed"); - goto error; - } - - CLEAR (*ks->key_src); - } - - gc_free (&gc); - return true; - - error: - CLEAR (*ks->key_src); - buf_clear (buf); - gc_free (&gc); - return false; -} - -/* - * This is the primary routine for processing TLS stuff inside the - * the main event loop. When this routine exits - * with non-error status, it will set *wakeup to the number of seconds - * when it wants to be called again. - * - * Return value is true if we have placed a packet in *to_link which we - * want to send to our peer. - */ -static bool -tls_process (struct tls_multi *multi, - struct tls_session *session, - struct buffer *to_link, - struct sockaddr_in *to_link_addr, - struct link_socket_info *to_link_socket_info, - interval_t *wakeup) -{ - struct gc_arena gc = gc_new (); - struct buffer *buf; - bool state_change = false; - bool active = false; - - /* Make sure we were initialized and that we're not in an error state */ - ASSERT (ks->state != S_UNDEF); - ASSERT (ks->state != S_ERROR); - ASSERT (session_id_defined (&session->session_id)); - - /* Should we trigger a soft reset? -- new key, keeps old key for a while */ - if (ks->state >= S_ACTIVE && - ((session->opt->renegotiate_seconds - && now >= ks->established + session->opt->renegotiate_seconds) - || (session->opt->renegotiate_bytes - && ks->n_bytes >= session->opt->renegotiate_bytes) - || (session->opt->renegotiate_packets - && ks->n_packets >= session->opt->renegotiate_packets) - || (packet_id_close_to_wrapping (&ks->packet_id.send)))) - { - msg (D_TLS_DEBUG_LOW, "TLS: soft reset sec=%d bytes=%d/%d pkts=%d/%d", - (int)(ks->established + session->opt->renegotiate_seconds - now), - ks->n_bytes, session->opt->renegotiate_bytes, - ks->n_packets, session->opt->renegotiate_packets); - key_state_soft_reset (session); - } - - /* Kill lame duck key transition_window seconds after primary key negotiation */ - if (lame_duck_must_die (session, wakeup)) { - key_state_free (ks_lame, true); - msg (D_TLS_DEBUG_LOW, "TLS: tls_process: killed expiring key"); - } - - /*mutex_cycle (multi->mutex);*/ - - do - { - update_time (); - - dmsg (D_TLS_DEBUG, "TLS: tls_process: chg=%d ks=%s lame=%s to_link->len=%d wakeup=%d", - state_change, - state_name (ks->state), - state_name (ks_lame->state), - to_link->len, - *wakeup); - - state_change = false; - - /* - * TLS activity is finished once we get to S_ACTIVE, - * though we will still process acknowledgements. - * - * CHANGED with 2.0 -> now we may send tunnel configuration - * info over the control channel. - */ - if (true) - { - /* Initial handshake */ - if (ks->state == S_INITIAL) - { - buf = reliable_get_buf_output_sequenced (ks->send_reliable); - if (buf) - { - ks->must_negotiate = now + session->opt->handshake_window; - - /* null buffer */ - reliable_mark_active_outgoing (ks->send_reliable, buf, ks->initial_opcode); - INCR_GENERATED; - - ks->state = S_PRE_START; - state_change = true; - dmsg (D_TLS_DEBUG, "TLS: Initial Handshake, sid=%s", - session_id_print (&session->session_id, &gc)); - -#ifdef ENABLE_MANAGEMENT - if (management && ks->initial_opcode != P_CONTROL_SOFT_RESET_V1) - { - management_set_state (management, - OPENVPN_STATE_WAIT, - NULL, - 0); - } -#endif - } - } - - /* Are we timed out on receive? */ - if (now >= ks->must_negotiate) - { - if (ks->state < S_ACTIVE) - { - msg (D_TLS_ERRORS, - "TLS Error: TLS key negotiation failed to occur within %d seconds (check your network connectivity)", - session->opt->handshake_window); - goto error; - } - else /* assume that ks->state == S_ACTIVE */ - { - dmsg (D_TLS_DEBUG_MED, "STATE S_NORMAL"); - ks->state = S_NORMAL; - ks->must_negotiate = 0; - } - } - - /* Wait for Initial Handshake ACK */ - if (ks->state == S_PRE_START && FULL_SYNC) - { - ks->state = S_START; - state_change = true; - dmsg (D_TLS_DEBUG_MED, "STATE S_START"); - } - - /* Wait for ACK */ - if (((ks->state == S_GOT_KEY && !session->opt->server) || - (ks->state == S_SENT_KEY && session->opt->server))) - { - if (FULL_SYNC) - { - ks->established = now; - dmsg (D_TLS_DEBUG_MED, "STATE S_ACTIVE"); - if (check_debug_level (D_HANDSHAKE)) - print_details (ks->ssl, "Control Channel:"); - state_change = true; - ks->state = S_ACTIVE; - INCR_SUCCESS; - - /* Set outgoing address for data channel packets */ - link_socket_set_outgoing_addr (NULL, to_link_socket_info, &ks->remote_addr, session->common_name, session->opt->es); - -#ifdef MEASURE_TLS_HANDSHAKE_STATS - show_tls_performance_stats(); -#endif - } - } - - /* Reliable buffer to outgoing TCP/UDP (send up to CONTROL_SEND_ACK_MAX ACKs - for previously received packets) */ - if (!to_link->len && reliable_can_send (ks->send_reliable)) - { - int opcode; - struct buffer b; - - buf = reliable_send (ks->send_reliable, &opcode); - ASSERT (buf); - b = *buf; - INCR_SENT; - - write_control_auth (session, ks, &b, to_link_addr, opcode, - CONTROL_SEND_ACK_MAX, true); - *to_link = b; - active = true; - state_change = true; - dmsg (D_TLS_DEBUG, "Reliable -> TCP/UDP"); - break; - } - -#ifndef TLS_AGGREGATE_ACK - /* Send 1 or more ACKs (each received control packet gets one ACK) */ - if (!to_link->len && !reliable_ack_empty (ks->rec_ack)) - { - buf = &ks->ack_write_buf; - ASSERT (buf_init (buf, FRAME_HEADROOM (&multi->opt.frame))); - write_control_auth (session, ks, buf, to_link_addr, P_ACK_V1, - RELIABLE_ACK_SIZE, false); - *to_link = *buf; - active = true; - state_change = true; - dmsg (D_TLS_DEBUG, "Dedicated ACK -> TCP/UDP"); - break; - } -#endif - - /* Write incoming ciphertext to TLS object */ - buf = reliable_get_buf_sequenced (ks->rec_reliable); - if (buf) - { - int status = 0; - if (buf->len) - { - status = key_state_write_ciphertext (multi, ks, buf); - if (status == -1) - { - msg (D_TLS_ERRORS, - "TLS Error: Incoming Ciphertext -> TLS object write error"); - goto error; - } - } - else - { - status = 1; - } - if (status == 1) - { - reliable_mark_deleted (ks->rec_reliable, buf, true); - state_change = true; - dmsg (D_TLS_DEBUG, "Incoming Ciphertext -> TLS"); - } - } - - /* Read incoming plaintext from TLS object */ - buf = &ks->plaintext_read_buf; - if (!buf->len) - { - int status; - - ASSERT (buf_init (buf, 0)); - status = key_state_read_plaintext (multi, ks, buf, PLAINTEXT_BUFFER_SIZE); - update_time (); - if (status == -1) - { - msg (D_TLS_ERRORS, "TLS Error: TLS object -> incoming plaintext read error"); - goto error; - } - if (status == 1) - { - state_change = true; - dmsg (D_TLS_DEBUG, "TLS -> Incoming Plaintext"); - } -#if 0 /* show null plaintext reads */ - if (!status) - msg (M_INFO, "TLS plaintext read -> NULL return"); -#endif - } - - /* Send Key */ - buf = &ks->plaintext_write_buf; - if (!buf->len && ((ks->state == S_START && !session->opt->server) || - (ks->state == S_GOT_KEY && session->opt->server))) - { - if (session->opt->key_method == 1) - { - if (!key_method_1_write (buf, session)) - goto error; - } - else if (session->opt->key_method == 2) - { - if (!key_method_2_write (buf, session)) - goto error; - } - else - { - ASSERT (0); - } - - state_change = true; - dmsg (D_TLS_DEBUG_MED, "STATE S_SENT_KEY"); - ks->state = S_SENT_KEY; - } - - /* Receive Key */ - buf = &ks->plaintext_read_buf; - if (buf->len - && ((ks->state == S_SENT_KEY && !session->opt->server) - || (ks->state == S_START && session->opt->server))) - { - if (session->opt->key_method == 1) - { - if (!key_method_1_read (buf, session)) - goto error; - } - else if (session->opt->key_method == 2) - { - if (!key_method_2_read (buf, multi, session)) - goto error; - } - else - { - ASSERT (0); - } - - state_change = true; - dmsg (D_TLS_DEBUG_MED, "STATE S_GOT_KEY"); - ks->state = S_GOT_KEY; - } - - /* Write outgoing plaintext to TLS object */ - buf = &ks->plaintext_write_buf; - if (buf->len) - { - int status = key_state_write_plaintext (multi, ks, buf); - if (status == -1) - { - msg (D_TLS_ERRORS, - "TLS ERROR: Outgoing Plaintext -> TLS object write error"); - goto error; - } - if (status == 1) - { - state_change = true; - dmsg (D_TLS_DEBUG, "Outgoing Plaintext -> TLS"); - } - } - - /* Outgoing Ciphertext to reliable buffer */ - if (ks->state >= S_START) - { - buf = reliable_get_buf_output_sequenced (ks->send_reliable); - if (buf) - { - int status = key_state_read_ciphertext (multi, ks, buf, PAYLOAD_SIZE_DYNAMIC (&multi->opt.frame)); - if (status == -1) - { - msg (D_TLS_ERRORS, - "TLS Error: Ciphertext -> reliable TCP/UDP transport read error"); - goto error; - } - if (status == 1) - { - reliable_mark_active_outgoing (ks->send_reliable, buf, P_CONTROL_V1); - INCR_GENERATED; - state_change = true; - dmsg (D_TLS_DEBUG, "Outgoing Ciphertext -> Reliable"); - } - } - } - } - /*mutex_cycle (multi->mutex);*/ - } - while (state_change); - - update_time (); - -#ifdef TLS_AGGREGATE_ACK - /* Send 1 or more ACKs (each received control packet gets one ACK) */ - if (!to_link->len && !reliable_ack_empty (ks->rec_ack)) - { - buf = &ks->ack_write_buf; - ASSERT (buf_init (buf, FRAME_HEADROOM (&multi->opt.frame))); - write_control_auth (session, ks, buf, to_link_addr, P_ACK_V1, - RELIABLE_ACK_SIZE, false); - *to_link = *buf; - active = true; - state_change = true; - dmsg (D_TLS_DEBUG, "Dedicated ACK -> TCP/UDP"); - } -#endif - - /* When should we wake up again? */ - { - if (ks->state >= S_INITIAL) - { - compute_earliest_wakeup (wakeup, - reliable_send_timeout (ks->send_reliable)); - - if (ks->must_negotiate) - compute_earliest_wakeup (wakeup, ks->must_negotiate - now); - } - - if (ks->established && session->opt->renegotiate_seconds) - compute_earliest_wakeup (wakeup, - ks->established + session->opt->renegotiate_seconds - now); - - /* prevent event-loop spinning by setting minimum wakeup of 1 second */ - if (*wakeup <= 0) - { - *wakeup = 1; - - /* if we had something to send to remote, but to_link was busy, - let caller know we need to be called again soon */ - active = true; - } - - dmsg (D_TLS_DEBUG, "TLS: tls_process: timeout set to %d", *wakeup); - - gc_free (&gc); - return active; - } - -error: - ERR_clear_error (); - ks->state = S_ERROR; - msg (D_TLS_ERRORS, "TLS Error: TLS handshake failed"); - INCR_ERROR; - gc_free (&gc); - return false; -} - -#undef ks -#undef ks_lame - -/* - * Called by the top-level event loop. - * - * Basically decides if we should call tls_process for - * the active or untrusted sessions. - */ - -bool -tls_multi_process (struct tls_multi *multi, - struct buffer *to_link, - struct sockaddr_in *to_link_addr, - struct link_socket_info *to_link_socket_info, - interval_t *wakeup) -{ - struct gc_arena gc = gc_new (); - int i; - bool active = false; - bool error = false; - - perf_push (PERF_TLS_MULTI_PROCESS); - - ERR_clear_error (); - - /* - * Process each session object having state of S_INITIAL or greater, - * and which has a defined remote IP addr. - */ - - for (i = 0; i < TM_SIZE; ++i) - { - struct tls_session *session = &multi->session[i]; - struct key_state *ks = &session->key[KS_PRIMARY]; - struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; - - /* set initial remote address */ - if (i == TM_ACTIVE && ks->state == S_INITIAL && - addr_defined (&to_link_socket_info->lsa->actual)) - ks->remote_addr = to_link_socket_info->lsa->actual; - - dmsg (D_TLS_DEBUG, - "TLS: tls_multi_process: i=%d state=%s, mysid=%s, stored-sid=%s, stored-ip=%s", - i, - state_name (ks->state), - session_id_print (&session->session_id, &gc), - session_id_print (&ks->session_id_remote, &gc), - print_sockaddr (&ks->remote_addr, &gc)); - - if (ks->state >= S_INITIAL && addr_defined (&ks->remote_addr)) - { - update_time (); - - if (tls_process (multi, session, to_link, to_link_addr, - to_link_socket_info, wakeup)) - active = true; - - /* - * If tls_process hits an error: - * (1) If the session has an unexpired lame duck key, preserve it. - * (2) Reinitialize the session. - * (3) Increment soft error count - */ - if (ks->state == S_ERROR) - { - ++multi->n_soft_errors; - - if (i == TM_ACTIVE) - error = true; - - if (i == TM_ACTIVE - && ks_lame->state >= S_ACTIVE - && !multi->opt.single_session) - move_session (multi, TM_LAME_DUCK, TM_ACTIVE, true); - else - reset_session (multi, session); - } - } - /*mutex_cycle (multi->mutex);*/ - } - - update_time (); - - /* - * If lame duck session expires, kill it. - */ - if (lame_duck_must_die (&multi->session[TM_LAME_DUCK], wakeup)) { - tls_session_free (&multi->session[TM_LAME_DUCK], true); - msg (D_TLS_DEBUG_LOW, "TLS: tls_multi_process: killed expiring key"); - } - - /* - * If untrusted session achieves TLS authentication, - * move it to active session, usurping any prior session. - * - * A semi-trusted session is one in which the certificate authentication - * succeeded (if cert verification is enabled) but the username/password - * verification failed. A semi-trusted session can forward data on the - * TLS control channel but not on the tunnel channel. - */ - if (DECRYPT_KEY_ENABLED (multi, &multi->session[TM_UNTRUSTED].key[KS_PRIMARY])) { - move_session (multi, TM_ACTIVE, TM_UNTRUSTED, true); - msg (D_TLS_DEBUG_LOW, "TLS: tls_multi_process: untrusted session promoted to %strusted", - tls_authenticated (multi) ? "" : "semi-"); - } - - /* - * A hard error means that TM_ACTIVE hit an S_ERROR state and that no - * other key state objects are S_ACTIVE or higher. - */ - if (error) - { - for (i = 0; i < (int) SIZE (multi->key_scan); ++i) - { - if (multi->key_scan[i]->state >= S_ACTIVE) - goto nohard; - } - ++multi->n_hard_errors; - } - nohard: - -#ifdef ENABLE_DEBUG - /* DEBUGGING -- flood peer with repeating connection attempts */ - { - const int throw_level = GREMLIN_CONNECTION_FLOOD_LEVEL (multi->opt.gremlin); - if (throw_level) - { - for (i = 0; i < (int) SIZE (multi->key_scan); ++i) - { - if (multi->key_scan[i]->state >= throw_level) - { - ++multi->n_hard_errors; - ++multi->n_soft_errors; - } - } - } - } -#endif - - perf_pop (); - gc_free (&gc); - return active; -} - -/* - * Pre and post-process the encryption & decryption buffers in order - * to implement a multiplexed TLS channel over the TCP/UDP port. - */ - -/* - * - * When we are in TLS mode, this is the first routine which sees - * an incoming packet. - * - * If it's a data packet, we set opt so that our caller can - * decrypt it. We also give our caller the appropriate decryption key. - * - * If it's a control packet, we authenticate it and process it, - * possibly creating a new tls_session if it represents the - * first packet of a new session. For control packets, we will - * also zero the size of *buf so that our caller ignores the - * packet on our return. - * - * Note that openvpn only allows one active session at a time, - * so a new session (once authenticated) will always usurp - * an old session. - * - * Return true if input was an authenticated control channel - * packet. - * - * If we are running in TLS thread mode, all public routines - * below this point must be called with the L_TLS lock held. - */ - -bool -tls_pre_decrypt (struct tls_multi *multi, - struct sockaddr_in *from, - struct buffer *buf, - struct crypto_options *opt) -{ - struct gc_arena gc = gc_new (); - bool ret = false; - - if (buf->len > 0) - { - int i; - int op; - int key_id; - - /* get opcode and key ID */ - { - uint8_t c = *BPTR (buf); - op = c >> P_OPCODE_SHIFT; - key_id = c & P_KEY_ID_MASK; - } - - if (op == P_DATA_V1) - { /* data channel packet */ - for (i = 0; i < KEY_SCAN_SIZE; ++i) - { - struct key_state *ks = multi->key_scan[i]; - - /* - * This is the basic test of TLS state compatibility between a local OpenVPN - * instance and its remote peer. - * - * If the test fails, it tells us that we are getting a packet from a source - * which claims reference to a prior negotiated TLS session, but the local - * OpenVPN instance has no memory of such a negotiation. - * - * It almost always occurs on UDP sessions when the passive side of the - * connection is restarted without the active side restarting as well (the - * passive side is the server which only listens for the connections, the - * active side is the client which initiates connections). - */ - if (DECRYPT_KEY_ENABLED (multi, ks) - && key_id == ks->key_id - && ks->authenticated - && addr_port_match(from, &ks->remote_addr)) - { - /* return appropriate data channel decrypt key in opt */ - opt->key_ctx_bi = &ks->key; - opt->packet_id = multi->opt.replay ? &ks->packet_id : NULL; - opt->pid_persist = NULL; - opt->flags &= multi->opt.crypto_flags_and; - opt->flags |= multi->opt.crypto_flags_or; - ASSERT (buf_advance (buf, 1)); - ++ks->n_packets; - ks->n_bytes += buf->len; - dmsg (D_TLS_DEBUG, - "TLS: data channel, key_id=%d, IP=%s", - key_id, print_sockaddr (from, &gc)); - gc_free (&gc); - return ret; - } -#if 0 /* keys out of sync? */ - else - { - dmsg (D_TLS_DEBUG, "TLS_PRE_DECRYPT: [%d] dken=%d rkid=%d lkid=%d auth=%d match=%d", - i, - DECRYPT_KEY_ENABLED (multi, ks), - key_id, - ks->key_id, - ks->authenticated, - addr_port_match (from, &ks->remote_addr)); - } -#endif - } - - msg (D_TLS_ERRORS, - "TLS Error: local/remote TLS keys are out of sync: %s [%d]", - print_sockaddr (from, &gc), key_id); - goto error; - } - else /* control channel packet */ - { - bool do_burst = false; - bool new_link = false; - struct session_id sid; /* remote session ID */ - - /* verify legal opcode */ - if (op < P_FIRST_OPCODE || op > P_LAST_OPCODE) - { - msg (D_TLS_ERRORS, - "TLS Error: unknown opcode received from %s op=%d", - print_sockaddr (from, &gc), op); - goto error; - } - - /* hard reset ? */ - if (is_hard_reset (op, 0)) - { - /* verify client -> server or server -> client connection */ - if (((op == P_CONTROL_HARD_RESET_CLIENT_V1 - || op == P_CONTROL_HARD_RESET_CLIENT_V2) && !multi->opt.server) - || ((op == P_CONTROL_HARD_RESET_SERVER_V1 - || op == P_CONTROL_HARD_RESET_SERVER_V2) && multi->opt.server)) - { - msg (D_TLS_ERRORS, - "TLS Error: client->client or server->server connection attempted from %s", - print_sockaddr (from, &gc)); - goto error; - } - } - - /* - * Authenticate Packet - */ - dmsg (D_TLS_DEBUG, "TLS: control channel, op=%s, IP=%s", - packet_opcode_name (op), print_sockaddr (from, &gc)); - - /* get remote session-id */ - { - struct buffer tmp = *buf; - buf_advance (&tmp, 1); - if (!session_id_read (&sid, &tmp) || !session_id_defined (&sid)) - { - msg (D_TLS_ERRORS, - "TLS Error: session-id not found in packet from %s", - print_sockaddr (from, &gc)); - goto error; - } - } - - /* use session ID to match up packet with appropriate tls_session object */ - for (i = 0; i < TM_SIZE; ++i) - { - struct tls_session *session = &multi->session[i]; - struct key_state *ks = &session->key[KS_PRIMARY]; - - dmsg (D_TLS_DEBUG, - "TLS: initial packet test, i=%d state=%s, mysid=%s, rec-sid=%s, rec-ip=%s, stored-sid=%s, stored-ip=%s", - i, - state_name (ks->state), - session_id_print (&session->session_id, &gc), - session_id_print (&sid, &gc), - print_sockaddr (from, &gc), - session_id_print (&ks->session_id_remote, &gc), - print_sockaddr (&ks->remote_addr, &gc)); - - if (session_id_equal (&ks->session_id_remote, &sid)) - /* found a match */ - { - if (i == TM_LAME_DUCK) { - msg (D_TLS_ERRORS, - "TLS ERROR: received control packet with stale session-id=%s", - session_id_print (&sid, &gc)); - goto error; - } - dmsg (D_TLS_DEBUG, - "TLS: found match, session[%d], sid=%s", - i, session_id_print (&sid, &gc)); - break; - } - } - - /* - * Initial packet received. - */ - - if (i == TM_SIZE && is_hard_reset (op, 0)) - { - struct tls_session *session = &multi->session[TM_ACTIVE]; - struct key_state *ks = &session->key[KS_PRIMARY]; - - if (!is_hard_reset (op, multi->opt.key_method)) - { - msg (D_TLS_ERRORS, "TLS ERROR: initial packet local/remote key_method mismatch, local key_method=%d, op=%s", - multi->opt.key_method, - packet_opcode_name (op)); - goto error; - } - - /* - * If we have no session currently in progress, the initial packet will - * open a new session in TM_ACTIVE rather than TM_UNTRUSTED. - */ - if (!session_id_defined (&ks->session_id_remote)) - { - if (multi->opt.single_session && multi->n_sessions) - { - msg (D_TLS_ERRORS, - "TLS Error: Cannot accept new session request from %s due to session context expire or --single-session [1]", - print_sockaddr (from, &gc)); - goto error; - } - -#ifdef ENABLE_MANAGEMENT - if (management) - { - management_set_state (management, - OPENVPN_STATE_AUTH, - NULL, - 0); - } -#endif - - msg (D_TLS_DEBUG_LOW, - "TLS: Initial packet from %s, sid=%s", - print_sockaddr (from, &gc), - session_id_print (&sid, &gc)); - - do_burst = true; - new_link = true; - i = TM_ACTIVE; - session->untrusted_sockaddr = *from; - } - } - - if (i == TM_SIZE && is_hard_reset (op, 0)) - { - /* - * No match with existing sessions, - * probably a new session. - */ - struct tls_session *session = &multi->session[TM_UNTRUSTED]; - - /* - * If --single-session, don't allow any hard-reset connection request - * unless it the the first packet of the session. - */ - if (multi->opt.single_session) - { - msg (D_TLS_ERRORS, - "TLS Error: Cannot accept new session request from %s due to session context expire or --single-session [2]", - print_sockaddr (from, &gc)); - goto error; - } - - if (!is_hard_reset (op, multi->opt.key_method)) - { - msg (D_TLS_ERRORS, "TLS ERROR: new session local/remote key_method mismatch, local key_method=%d, op=%s", - multi->opt.key_method, - packet_opcode_name (op)); - goto error; - } - - if (!read_control_auth (buf, &session->tls_auth, from)) - goto error; - - /* - * New session-initiating control packet is authenticated at this point, - * assuming that the --tls-auth command line option was used. - * - * Without --tls-auth, we leave authentication entirely up to TLS. - */ - msg (D_TLS_DEBUG_LOW, - "TLS: new session incoming connection from %s", - print_sockaddr (from, &gc)); - - new_link = true; - i = TM_UNTRUSTED; - session->untrusted_sockaddr = *from; - } - else - { - struct tls_session *session = &multi->session[i]; - struct key_state *ks = &session->key[KS_PRIMARY]; - - /* - * Packet must belong to an existing session. - */ - if (i != TM_ACTIVE && i != TM_UNTRUSTED) - { - msg (D_TLS_ERRORS, - "TLS Error: Unroutable control packet received from %s (si=%d op=%s)", - print_sockaddr (from, &gc), - i, - packet_opcode_name (op)); - goto error; - } - - /* - * Verify remote IP address - */ - if (!new_link && !addr_port_match (&ks->remote_addr, from)) - { - msg (D_TLS_ERRORS, "TLS Error: Received control packet from unexpected IP addr: %s", - print_sockaddr (from, &gc)); - goto error; - } - - /* - * Remote is requesting a key renegotiation - */ - if (op == P_CONTROL_SOFT_RESET_V1 - && DECRYPT_KEY_ENABLED (multi, ks)) - { - if (!read_control_auth (buf, &session->tls_auth, from)) - goto error; - - key_state_soft_reset (session); - - dmsg (D_TLS_DEBUG, - "TLS: received P_CONTROL_SOFT_RESET_V1 s=%d sid=%s", - i, session_id_print (&sid, &gc)); - } - else - { - /* - * Remote responding to our key renegotiation request? - */ - if (op == P_CONTROL_SOFT_RESET_V1) - do_burst = true; - - if (!read_control_auth (buf, &session->tls_auth, from)) - goto error; - - dmsg (D_TLS_DEBUG, - "TLS: received control channel packet s#=%d sid=%s", - i, session_id_print (&sid, &gc)); - } - } - - /* - * We have an authenticated packet (if --tls-auth was set). - * Now pass to our reliability level which deals with - * packet acknowledgements, retransmits, sequencing, etc. - */ - { - struct tls_session *session = &multi->session[i]; - struct key_state *ks = &session->key[KS_PRIMARY]; - - /* Make sure we were initialized and that we're not in an error state */ - ASSERT (ks->state != S_UNDEF); - ASSERT (ks->state != S_ERROR); - ASSERT (session_id_defined (&session->session_id)); - - /* Let our caller know we processed a control channel packet */ - ret = true; - - /* - * Set our remote address and remote session_id - */ - if (new_link) - { - ks->session_id_remote = sid; - ks->remote_addr = *from; - ++multi->n_sessions; - } - else if (!addr_port_match (&ks->remote_addr, from)) - { - msg (D_TLS_ERRORS, - "TLS Error: Existing session control channel packet from unknown IP address: %s", - print_sockaddr (from, &gc)); - goto error; - } - - /* - * Should we do a retransmit of all unacknowledged packets in - * the send buffer? This improves the start-up efficiency of the - * initial key negotiation after the 2nd peer comes online. - */ - if (do_burst && !session->burst) - { - reliable_schedule_now (ks->send_reliable); - session->burst = true; - } - - /* Check key_id */ - if (ks->key_id != key_id) - { - msg (D_TLS_ERRORS, - "TLS ERROR: local/remote key IDs out of sync (%d/%d) ID: %s", - ks->key_id, key_id, print_key_id (multi, &gc)); - goto error; - } - - /* - * Process incoming ACKs for packets we can now - * delete from reliable send buffer - */ - { - /* buffers all packet IDs to delete from send_reliable */ - struct reliable_ack send_ack; - - send_ack.len = 0; - if (!reliable_ack_read (&send_ack, buf, &session->session_id)) - { - msg (D_TLS_ERRORS, - "TLS Error: reading acknowledgement record from packet"); - goto error; - } - reliable_send_purge (ks->send_reliable, &send_ack); - } - - if (op != P_ACK_V1 && reliable_can_get (ks->rec_reliable)) - { - packet_id_type id; - - /* Extract the packet ID from the packet */ - if (reliable_ack_read_packet_id (buf, &id)) - { - /* Avoid deadlock by rejecting packet that would de-sequentialize receive buffer */ - if (reliable_wont_break_sequentiality (ks->rec_reliable, id)) - { - if (reliable_not_replay (ks->rec_reliable, id)) - { - /* Save incoming ciphertext packet to reliable buffer */ - struct buffer *in = reliable_get_buf (ks->rec_reliable); - ASSERT (in); - ASSERT (buf_copy (in, buf)); - reliable_mark_active_incoming (ks->rec_reliable, in, id, op); - } - - /* Process outgoing acknowledgment for packet just received, even if it's a replay */ - reliable_ack_acknowledge_packet_id (ks->rec_ack, id); - } - } - } - } - } - } - - done: - buf->len = 0; - opt->key_ctx_bi = NULL; - opt->packet_id = NULL; - opt->pid_persist = NULL; - opt->flags &= multi->opt.crypto_flags_and; - gc_free (&gc); - return ret; - - error: - ERR_clear_error (); - ++multi->n_soft_errors; - goto done; -} - -/* - * This function is similar to tls_pre_decrypt, except it is called - * when we are in server mode and receive an initial incoming - * packet. Note that we don't modify - * any state in our parameter objects. The purpose is solely to - * determine whether we should generate a client instance - * object, in which case true is returned. - * - * This function is essentially the first-line HMAC firewall - * on the UDP port listener in --mode server mode. - */ -bool -tls_pre_decrypt_lite (const struct tls_auth_standalone *tas, - const struct sockaddr_in *from, - const struct buffer *buf) -{ - struct gc_arena gc = gc_new (); - bool ret = false; - - if (buf->len > 0) - { - int op; - int key_id; - - /* get opcode and key ID */ - { - uint8_t c = *BPTR (buf); - op = c >> P_OPCODE_SHIFT; - key_id = c & P_KEY_ID_MASK; - } - - /* this packet is from an as-yet untrusted source, so - scrutinize carefully */ - - if (op != P_CONTROL_HARD_RESET_CLIENT_V2) - { - /* - * This can occur due to bogus data or DoS packets. - */ - dmsg (D_TLS_STATE_ERRORS, - "TLS State Error: No TLS state for client %s, opcode=%d", - print_sockaddr (from, &gc), - op); - goto error; - } - - if (key_id != 0) - { - dmsg (D_TLS_STATE_ERRORS, - "TLS State Error: Unknown key ID (%d) received from %s -- 0 was expected", - key_id, - print_sockaddr (from, &gc)); - goto error; - } - - if (buf->len > EXPANDED_SIZE_DYNAMIC (&tas->frame)) - { - dmsg (D_TLS_STATE_ERRORS, - "TLS State Error: Large packet (size %d) received from %s -- a packet no larger than %d bytes was expected", - buf->len, - print_sockaddr (from, &gc), - EXPANDED_SIZE_DYNAMIC (&tas->frame)); - goto error; - } - - { - struct buffer newbuf = clone_buf (buf); - struct crypto_options co = tas->tls_auth_options; - bool status; - - /* - * We are in read-only mode at this point with respect to TLS - * control channel state. After we build a new client instance - * object, we will process this session-initiating packet for real. - */ - co.flags |= CO_IGNORE_PACKET_ID; - - /* HMAC test, if --tls-auth was specified */ - status = read_control_auth (&newbuf, &co, from); - free_buf (&newbuf); - if (!status) - goto error; - - /* - * At this point, if --tls-auth is being used, we know that - * the packet has passed the HMAC test, but we don't know if - * it is a replay yet. We will attempt to defeat replays - * by not advancing to the S_START state until we - * receive an ACK from our first reply to the client - * that includes an HMAC of our randomly generated 64 bit - * session ID. - * - * On the other hand if --tls-auth is not being used, we - * will proceed to begin the TLS authentication - * handshake with only cursory integrity checks having - * been performed, since we will be leaving the task - * of authentication solely up to TLS. - */ - - ret = true; - } - } - gc_free (&gc); - return ret; - - error: - ERR_clear_error (); - gc_free (&gc); - return ret; -} - -/* Choose the key with which to encrypt a data packet */ -void -tls_pre_encrypt (struct tls_multi *multi, - struct buffer *buf, struct crypto_options *opt) -{ - multi->save_ks = NULL; - if (buf->len > 0) - { - int i; - for (i = 0; i < KEY_SCAN_SIZE; ++i) - { - struct key_state *ks = multi->key_scan[i]; - if (ks->state >= S_ACTIVE && ks->authenticated) - { - opt->key_ctx_bi = &ks->key; - opt->packet_id = multi->opt.replay ? &ks->packet_id : NULL; - opt->pid_persist = NULL; - opt->flags &= multi->opt.crypto_flags_and; - opt->flags |= multi->opt.crypto_flags_or; - multi->save_ks = ks; - dmsg (D_TLS_DEBUG, "TLS: tls_pre_encrypt: key_id=%d", ks->key_id); - return; - } - } - - { - struct gc_arena gc = gc_new (); - dmsg (D_TLS_NO_SEND_KEY, "TLS Warning: no data channel send key available: %s", - print_key_id (multi, &gc)); - gc_free (&gc); - } - } - - buf->len = 0; - opt->key_ctx_bi = NULL; - opt->packet_id = NULL; - opt->pid_persist = NULL; - opt->flags &= multi->opt.crypto_flags_and; -} - -/* Prepend the appropriate opcode to encrypted buffer prior to TCP/UDP send */ -void -tls_post_encrypt (struct tls_multi *multi, struct buffer *buf) -{ - struct key_state *ks; - uint8_t *op; - - ks = multi->save_ks; - multi->save_ks = NULL; - if (buf->len > 0) - { - ASSERT (ks); - ASSERT (op = buf_prepend (buf, 1)); - *op = (P_DATA_V1 << P_OPCODE_SHIFT) | ks->key_id; - ++ks->n_packets; - ks->n_bytes += buf->len; - } -} - -/* - * Send a payload over the TLS control channel. - * Called externally. - */ - -bool -tls_send_payload (struct tls_multi *multi, - const uint8_t *data, - int size) -{ - struct tls_session *session; - struct key_state *ks; - bool ret = false; - - ERR_clear_error (); - - ASSERT (multi); - - session = &multi->session[TM_ACTIVE]; - ks = &session->key[KS_PRIMARY]; - - if (ks->state >= S_ACTIVE) - { - if (key_state_write_plaintext_const (multi, ks, data, size) == 1) - ret = true; - } - - ERR_clear_error (); - - return ret; -} - -bool -tls_rec_payload (struct tls_multi *multi, - struct buffer *buf) -{ - struct tls_session *session; - struct key_state *ks; - bool ret = false; - - ERR_clear_error (); - - ASSERT (multi); - - session = &multi->session[TM_ACTIVE]; - ks = &session->key[KS_PRIMARY]; - - if (ks->state >= S_ACTIVE && BLEN (&ks->plaintext_read_buf)) - { - if (buf_copy (buf, &ks->plaintext_read_buf)) - ret = true; - ks->plaintext_read_buf.len = 0; - } - - ERR_clear_error (); - - return ret; -} - -/* - * Dump a human-readable rendition of an openvpn packet - * into a garbage collectable string which is returned. - */ -const char * -protocol_dump (struct buffer *buffer, unsigned int flags, struct gc_arena *gc) -{ - struct buffer out = alloc_buf_gc (256, gc); - struct buffer buf = *buffer; - - uint8_t c; - int op; - int key_id; - - int tls_auth_hmac_size = (flags & PD_TLS_AUTH_HMAC_SIZE_MASK); - - if (buf.len <= 0) - { - buf_printf (&out, "DATA UNDEF len=%d", buf.len); - goto done; - } - - if (!(flags & PD_TLS)) - goto print_data; - - /* - * Initial byte (opcode) - */ - if (!buf_read (&buf, &c, sizeof (c))) - goto done; - op = (c >> P_OPCODE_SHIFT); - key_id = c & P_KEY_ID_MASK; - buf_printf (&out, "%s kid=%d", packet_opcode_name (op), key_id); - - if (op == P_DATA_V1) - goto print_data; - - /* - * Session ID - */ - { - struct session_id sid; - - if (!session_id_read (&sid, &buf)) - goto done; - if (flags & PD_VERBOSE) - buf_printf (&out, " sid=%s", session_id_print (&sid, gc)); - } - - /* - * tls-auth hmac + packet_id - */ - if (tls_auth_hmac_size) - { - struct packet_id_net pin; - uint8_t tls_auth_hmac[MAX_HMAC_KEY_LENGTH]; - - ASSERT (tls_auth_hmac_size <= MAX_HMAC_KEY_LENGTH); - - if (!buf_read (&buf, tls_auth_hmac, tls_auth_hmac_size)) - goto done; - if (flags & PD_VERBOSE) - buf_printf (&out, " tls_hmac=%s", format_hex (tls_auth_hmac, tls_auth_hmac_size, 0, gc)); - - if (!packet_id_read (&pin, &buf, true)) - goto done; - buf_printf(&out, " pid=%s", packet_id_net_print (&pin, (flags & PD_VERBOSE), gc)); - } - - /* - * ACK list - */ - buf_printf (&out, " %s", reliable_ack_print(&buf, (flags & PD_VERBOSE), gc)); - - if (op == P_ACK_V1) - goto done; - - /* - * Packet ID - */ - { - packet_id_type l; - if (!buf_read (&buf, &l, sizeof (l))) - goto done; - l = ntohpid (l); - buf_printf (&out, " pid=" packet_id_format, (packet_id_print_type)l); - } - -print_data: - if (flags & PD_SHOW_DATA) - buf_printf (&out, " DATA %s", format_hex (BPTR (&buf), BLEN (&buf), 80, gc)); - else - buf_printf (&out, " DATA len=%d", buf.len); - -done: - return BSTR (&out); -} - -#ifdef EXTRACT_X509_FIELD_TEST - -void -extract_x509_field_test (void) -{ - char line[8]; - char field[4]; - static const char field_name[] = "CN"; - - while (fgets (line, sizeof (line), stdin)) - { - chomp (line); - extract_x509_field (line, field_name, field, sizeof (field)); - printf ("CN: '%s'\n", field); - } -} - -#endif - -#else -static void dummy(void) {} -#endif /* USE_CRYPTO && USE_SSL*/ |