diff options
Diffstat (limited to 'src/openvpn/ssl_verify.c')
| -rw-r--r-- | src/openvpn/ssl_verify.c | 1265 |
1 files changed, 1265 insertions, 0 deletions
diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c new file mode 100644 index 0000000..cac46e9 --- /dev/null +++ b/src/openvpn/ssl_verify.c @@ -0,0 +1,1265 @@ +/* + * OpenVPN -- An application to securely tunnel IP networks + * over a single TCP/UDP port, with support for SSL/TLS-based + * session authentication and key exchange, + * packet encryption, packet authentication, and + * packet compression. + * + * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net> + * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program (see the file COPYING included with this + * distribution); if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +/** + * @file Control Channel Verification Module + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#elif defined(_MSC_VER) +#include "config-msvc.h" +#endif + +#include "syshead.h" + +#if defined(ENABLE_CRYPTO) && defined(ENABLE_SSL) + +#include "misc.h" +#include "manage.h" +#include "ssl_verify.h" +#include "ssl_verify_backend.h" + +#ifdef ENABLE_CRYPTO_OPENSSL +#include "ssl_verify_openssl.h" +#endif + +/** Maximum length of common name */ +#define TLS_USERNAME_LEN 64 + +/** Legal characters in an X509 name with --compat-names */ +#define X509_NAME_CHAR_CLASS (CC_ALNUM|CC_UNDERBAR|CC_DASH|CC_DOT|CC_AT|CC_SLASH|CC_COLON|CC_EQUAL) + +/** Legal characters in a common name with --compat-names */ +#define COMMON_NAME_CHAR_CLASS (CC_ALNUM|CC_UNDERBAR|CC_DASH|CC_DOT|CC_AT|CC_SLASH) + +static void +string_mod_remap_name (char *str, const unsigned int restrictive_flags) +{ + if (compat_flag (COMPAT_FLAG_QUERY | COMPAT_NAMES) + && !compat_flag (COMPAT_FLAG_QUERY | COMPAT_NO_NAME_REMAPPING)) + string_mod (str, restrictive_flags, 0, '_'); + else + string_mod (str, CC_PRINT, CC_CRLF, '_'); +} + +/* + * Export the untrusted IP address and port to the environment + */ +static void +setenv_untrusted (struct tls_session *session) +{ + setenv_link_socket_actual (session->opt->es, "untrusted", &session->untrusted_addr, SA_IP_PORT); +} + +/* + * Remove authenticated state from all sessions in the given tunnel + */ +static 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; + } +} + +/* + * Set the given session's common_name + */ +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; +#ifdef ENABLE_PF + session->common_name_hashval = 0; +#endif + } + if (common_name) + { + /* FIXME: Last alloc will never be freed */ + session->common_name = string_alloc (common_name, NULL); +#ifdef ENABLE_PF + { + const uint32_t len = (uint32_t) strlen (common_name); + if (len) + session->common_name_hashval = hash_func ((const uint8_t*)common_name, len+1, 0); + else + session->common_name_hashval = 0; + } +#endif + } +} + +/* + * Retrieve the common name for the given tunnel's active session. If the + * common name is NULL or empty, return NULL if null is true, or "UNDEF" if + * null is false. + */ +const char * +tls_common_name (const struct tls_multi *multi, const 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"; +} + +/* + * Lock the common name for the given tunnel. + */ +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); +} + +/* + * Lock the username for the given tunnel + */ +static bool +tls_lock_username (struct tls_multi *multi, const char *username) +{ + if (multi->locked_username) + { + if (!username || strcmp (username, multi->locked_username)) + { + msg (D_TLS_ERRORS, "TLS Auth Error: username attempted to change from '%s' to '%s' -- tunnel disabled", + multi->locked_username, + np(username)); + + /* disable the tunnel */ + tls_deauthenticate (multi); + return false; + } + } + else + { + if (username) + multi->locked_username = string_alloc (username, NULL); + } + return true; +} + +const char * +tls_username (const struct tls_multi *multi, const bool null) +{ + const char *ret = NULL; + if (multi) + ret = multi->locked_username; + if (ret && strlen (ret)) + return ret; + else if (null) + return NULL; + else + return "UNDEF"; +} + +void +cert_hash_remember (struct tls_session *session, const int error_depth, const unsigned char *sha1_hash) +{ + if (error_depth >= 0 && error_depth < MAX_CERT_DEPTH) + { + if (!session->cert_hash_set) + ALLOC_OBJ_CLEAR (session->cert_hash_set, struct cert_hash_set); + if (!session->cert_hash_set->ch[error_depth]) + ALLOC_OBJ (session->cert_hash_set->ch[error_depth], struct cert_hash); + { + struct cert_hash *ch = session->cert_hash_set->ch[error_depth]; + memcpy (ch->sha1_hash, sha1_hash, SHA_DIGEST_LENGTH); + } + } +} + +#if 0 +static void +cert_hash_print (const struct cert_hash_set *chs, int msglevel) +{ + struct gc_arena gc = gc_new (); + msg (msglevel, "CERT_HASH"); + if (chs) + { + int i; + for (i = 0; i < MAX_CERT_DEPTH; ++i) + { + const struct cert_hash *ch = chs->ch[i]; + if (ch) + msg (msglevel, "%d:%s", i, format_hex(ch->sha1_hash, SHA_DIGEST_LENGTH, 0, &gc)); + } + } + gc_free (&gc); +} +#endif + +void +cert_hash_free (struct cert_hash_set *chs) +{ + if (chs) + { + int i; + for (i = 0; i < MAX_CERT_DEPTH; ++i) + free (chs->ch[i]); + free (chs); + } +} + +static bool +cert_hash_compare (const struct cert_hash_set *chs1, const struct cert_hash_set *chs2) +{ + if (chs1 && chs2) + { + int i; + for (i = 0; i < MAX_CERT_DEPTH; ++i) + { + const struct cert_hash *ch1 = chs1->ch[i]; + const struct cert_hash *ch2 = chs2->ch[i]; + + if (!ch1 && !ch2) + continue; + else if (ch1 && ch2 && !memcmp (ch1->sha1_hash, ch2->sha1_hash, SHA_DIGEST_LENGTH)) + continue; + else + return false; + } + return true; + } + else if (!chs1 && !chs2) + return true; + else + return false; +} + +static struct cert_hash_set * +cert_hash_copy (const struct cert_hash_set *chs) +{ + struct cert_hash_set *dest = NULL; + if (chs) + { + int i; + ALLOC_OBJ_CLEAR (dest, struct cert_hash_set); + for (i = 0; i < MAX_CERT_DEPTH; ++i) + { + const struct cert_hash *ch = chs->ch[i]; + if (ch) + { + ALLOC_OBJ (dest->ch[i], struct cert_hash); + memcpy (dest->ch[i]->sha1_hash, ch->sha1_hash, SHA_DIGEST_LENGTH); + } + } + } + return dest; +} +void +tls_lock_cert_hash_set (struct tls_multi *multi) +{ + const struct cert_hash_set *chs = multi->session[TM_ACTIVE].cert_hash_set; + if (chs && !multi->locked_cert_hash_set) + multi->locked_cert_hash_set = cert_hash_copy (chs); +} + +/* + * Returns the string associated with the given certificate type. + */ +static const char * +print_nsCertType (int type) +{ + switch (type) + { + case NS_CERT_CHECK_SERVER: + return "SERVER"; + case NS_CERT_CHECK_CLIENT: + return "CLIENT"; + default: + return "?"; + } +} + +/* + * Verify the peer's certificate fields. + * + * @param opt the tls options to verify against + * @param peer_cert the peer's certificate + * @param subject the peer's extracted subject name + * @param subject the peer's extracted common name + */ +static result_t +verify_peer_cert(const struct tls_options *opt, openvpn_x509_cert_t *peer_cert, + const char *subject, const char *common_name) +{ + /* verify certificate nsCertType */ + if (opt->ns_cert_type != NS_CERT_CHECK_NONE) + { + if (SUCCESS == x509_verify_ns_cert_type (peer_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)); + return FAILURE; /* Reject connection */ + } + } + +#if OPENSSL_VERSION_NUMBER >= 0x00907000L || ENABLE_CRYPTO_POLARSSL + + /* verify certificate ku */ + if (opt->remote_cert_ku[0] != 0) + { + if (SUCCESS == x509_verify_cert_ku (peer_cert, opt->remote_cert_ku, MAX_PARMS)) + { + msg (D_HANDSHAKE, "VERIFY KU OK"); + } + else + { + msg (D_HANDSHAKE, "VERIFY KU ERROR"); + return FAILURE; /* Reject connection */ + } + } + + /* verify certificate eku */ + if (opt->remote_cert_eku != NULL) + { + if (SUCCESS == x509_verify_cert_eku (peer_cert, opt->remote_cert_eku)) + { + msg (D_HANDSHAKE, "VERIFY EKU OK"); + } + else + { + msg (D_HANDSHAKE, "VERIFY EKU ERROR"); + return FAILURE; /* Reject connection */ + } + } + +#endif /* OPENSSL_VERSION_NUMBER */ + + /* verify X509 name or common name against --tls-remote */ + if (opt->verify_x509name && strlen (opt->verify_x509name) > 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); + return FAILURE; /* Reject connection */ + } + } + + return SUCCESS; +} + +/* + * Export the subject, common_name, and raw certificate fields to the + * environment for later verification by scripts and plugins. + */ +static void +verify_cert_set_env(struct env_set *es, openvpn_x509_cert_t *peer_cert, int cert_depth, + const char *subject, const char *common_name +#ifdef ENABLE_X509_TRACK + , const struct x509_track *x509_track +#endif + ) +{ + char envname[64]; + char *serial = NULL; + struct gc_arena gc = gc_new (); + + /* Save X509 fields in environment */ +#ifdef ENABLE_X509_TRACK + if (x509_track) + x509_setenv_track (x509_track, es, cert_depth, peer_cert); + else +#endif + x509_setenv (es, cert_depth, peer_cert); + + /* export subject name string as environmental variable */ + openvpn_snprintf (envname, sizeof(envname), "tls_id_%d", cert_depth); + setenv_str (es, envname, subject); + +#if 0 + /* export common name string as environmental variable */ + openvpn_snprintf (envname, sizeof(envname), "tls_common_name_%d", cert_depth); + setenv_str (es, envname, common_name); +#endif + +#ifdef ENABLE_EUREPHIA + /* export X509 cert SHA1 fingerprint */ + { + unsigned char *sha1_hash = x509_get_sha1_hash(peer_cert, &gc); + + openvpn_snprintf (envname, sizeof(envname), "tls_digest_%d", cert_depth); + setenv_str (es, envname, format_hex_ex(sha1_hash, SHA_DIGEST_LENGTH, 0, 1, + ":", &gc)); + } +#endif + + /* export serial number as environmental variable */ + serial = x509_get_serial(peer_cert, &gc); + openvpn_snprintf (envname, sizeof(envname), "tls_serial_%d", cert_depth); + setenv_str (es, envname, serial); + + gc_free(&gc); +} + +/* + * call --tls-verify plug-in(s) + */ +static result_t +verify_cert_call_plugin(const struct plugin_list *plugins, struct env_set *es, + int cert_depth, openvpn_x509_cert_t *cert, char *subject) +{ + if (plugin_defined (plugins, OPENVPN_PLUGIN_TLS_VERIFY)) + { + int ret; + struct argv argv = argv_new (); + + argv_printf (&argv, "%d %s", cert_depth, subject); + + ret = plugin_call_ssl (plugins, OPENVPN_PLUGIN_TLS_VERIFY, &argv, NULL, es, cert_depth, cert); + + argv_reset (&argv); + + if (ret == OPENVPN_PLUGIN_FUNC_SUCCESS) + { + msg (D_HANDSHAKE, "VERIFY PLUGIN OK: depth=%d, %s", + cert_depth, subject); + } + else + { + msg (D_HANDSHAKE, "VERIFY PLUGIN ERROR: depth=%d, %s", + cert_depth, subject); + return FAILURE; /* Reject connection */ + } + } + return SUCCESS; +} + +static const char * +verify_cert_export_cert(openvpn_x509_cert_t *peercert, const char *tmp_dir, struct gc_arena *gc) +{ + FILE *peercert_file; + const char *peercert_filename=""; + + if(!tmp_dir) + return NULL; + + /* create tmp file to store peer cert */ + peercert_filename = create_temp_file (tmp_dir, "pcf", gc); + + /* write peer-cert in tmp-file */ + peercert_file = fopen(peercert_filename, "w+"); + if(!peercert_file) + { + msg (M_ERR, "Failed to open temporary file : %s", peercert_filename); + return NULL; + } + + if (SUCCESS != x509_write_pem(peercert_file, peercert)) + msg (M_ERR, "Error writing PEM file containing certificate"); + + fclose(peercert_file); + return peercert_filename; +} + + +/* + * run --tls-verify script + */ +static result_t +verify_cert_call_command(const char *verify_command, struct env_set *es, + int cert_depth, openvpn_x509_cert_t *cert, char *subject, const char *verify_export_cert) +{ + const char *tmp_file = NULL; + int ret; + struct gc_arena gc = gc_new(); + struct argv argv = argv_new (); + + setenv_str (es, "script_type", "tls-verify"); + + if (verify_export_cert) + { + if ((tmp_file=verify_cert_export_cert(cert, verify_export_cert, &gc))) + { + setenv_str(es, "peer_cert", tmp_file); + } + } + + argv_printf (&argv, "%sc %d %s", verify_command, cert_depth, subject); + + argv_msg_prefix (D_TLS_DEBUG, &argv, "TLS: executing verify command"); + ret = openvpn_run_script (&argv, es, 0, "--tls-verify script"); + + if (verify_export_cert) + { + if (tmp_file) + platform_unlink(tmp_file); + } + + gc_free(&gc); + argv_reset (&argv); + + if (ret) + { + msg (D_HANDSHAKE, "VERIFY SCRIPT OK: depth=%d, %s", + cert_depth, subject); + return SUCCESS; + } + + msg (D_HANDSHAKE, "VERIFY SCRIPT ERROR: depth=%d, %s", + cert_depth, subject); + return FAILURE; /* Reject connection */ +} + +/* + * check peer cert against CRL directory + */ +static result_t +verify_check_crl_dir(const char *crl_dir, openvpn_x509_cert_t *cert) +{ + result_t ret = FAILURE; + char fn[256]; + int fd = -1; + struct gc_arena gc = gc_new(); + + char *serial = x509_get_serial(cert, &gc); + + if (!openvpn_snprintf(fn, sizeof(fn), "%s%c%s", crl_dir, OS_SPECIFIC_DIRSEP, serial)) + { + msg (D_HANDSHAKE, "VERIFY CRL: filename overflow"); + goto cleanup; + } + fd = platform_open (fn, O_RDONLY, 0); + if (fd >= 0) + { + msg (D_HANDSHAKE, "VERIFY CRL: certificate serial number %s is revoked", serial); + goto cleanup; + } + + ret = SUCCESS; + +cleanup: + + if (fd != -1) + close(fd); + gc_free(&gc); + return ret; +} + +result_t +verify_cert(struct tls_session *session, openvpn_x509_cert_t *cert, int cert_depth) +{ + result_t ret = FAILURE; + char *subject = NULL; + char common_name[TLS_USERNAME_LEN] = {0}; + const struct tls_options *opt; + struct gc_arena gc = gc_new(); + + opt = session->opt; + ASSERT (opt); + + session->verified = false; + + /* get the X509 name */ + subject = x509_get_subject(cert, &gc); + if (!subject) + { + msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, could not extract X509 " + "subject string from certificate", cert_depth); + goto cleanup; + } + + /* enforce character class restrictions in X509 name */ + string_mod_remap_name (subject, X509_NAME_CHAR_CLASS); + string_replace_leading (subject, '-', '_'); + + /* extract the username (default is CN) */ + if (SUCCESS != x509_get_username (common_name, TLS_USERNAME_LEN, + opt->x509_username_field, cert)) + { + if (!cert_depth) + { + msg (D_TLS_ERRORS, "VERIFY ERROR: could not extract %s from X509 " + "subject string ('%s') -- note that the username length is " + "limited to %d characters", + opt->x509_username_field, + subject, + TLS_USERNAME_LEN); + goto cleanup; + } + } + + /* enforce character class restrictions in common name */ + string_mod_remap_name (common_name, COMMON_NAME_CHAR_CLASS); + + /* warn if cert chain is too deep */ + if (cert_depth >= MAX_CERT_DEPTH) + { + msg (D_TLS_ERRORS, "TLS Error: Convoluted certificate chain detected with depth [%d] greater than %d", cert_depth, MAX_CERT_DEPTH); + goto cleanup; /* Reject connection */ + } + + /* verify level 1 cert, i.e. the CA that signed our leaf cert */ + if (cert_depth == 1 && opt->verify_hash) + { + unsigned char *sha1_hash = x509_get_sha1_hash(cert, &gc); + if (memcmp (sha1_hash, opt->verify_hash, SHA_DIGEST_LENGTH)) + { + msg (D_TLS_ERRORS, "TLS Error: level-1 certificate hash verification failed"); + goto cleanup; + } + } + + /* save common name in session object */ + if (cert_depth == 0) + set_common_name (session, common_name); + + session->verify_maxlevel = max_int (session->verify_maxlevel, cert_depth); + + /* export certificate values to the environment */ + verify_cert_set_env(opt->es, cert, cert_depth, subject, common_name +#ifdef ENABLE_X509_TRACK + , opt->x509_track +#endif + ); + + /* export current untrusted IP */ + setenv_untrusted (session); + + /* If this is the peer's own certificate, verify it */ + if (cert_depth == 0 && SUCCESS != verify_peer_cert(opt, cert, subject, common_name)) + goto cleanup; + + /* call --tls-verify plug-in(s), if registered */ + if (SUCCESS != verify_cert_call_plugin(opt->plugins, opt->es, cert_depth, cert, subject)) + goto cleanup; + + /* run --tls-verify script */ + if (opt->verify_command && SUCCESS != verify_cert_call_command(opt->verify_command, + opt->es, cert_depth, cert, subject, opt->verify_export_cert)) + goto cleanup; + + /* check peer cert against CRL */ + if (opt->crl_file) + { + if (opt->ssl_flags & SSLF_CRL_VERIFY_DIR) + { + if (SUCCESS != verify_check_crl_dir(opt->crl_file, cert)) + goto cleanup; + } + else + { + if (SUCCESS != x509_verify_crl(opt->crl_file, cert, subject)) + goto cleanup; + } + } + + msg (D_HANDSHAKE, "VERIFY OK: depth=%d, %s", cert_depth, subject); + session->verified = true; + ret = SUCCESS; + +cleanup: + + if (ret != SUCCESS) + { + tls_clear_error(); /* always? */ + session->verified = false; /* double sure? */ + } + gc_free(&gc); + + return ret; +} + +/* *************************************************************************** + * Functions for the management of deferred authentication when using + * user/password authentication. + *************************************************************************** */ + +#ifdef ENABLE_DEF_AUTH +/* key_state_test_auth_control_file return values, + NOTE: acf_merge indexing depends on these values */ +#define ACF_UNDEFINED 0 +#define ACF_SUCCEEDED 1 +#define ACF_DISABLED 2 +#define ACF_FAILED 3 +#endif + +#ifdef MANAGEMENT_DEF_AUTH +void +man_def_auth_set_client_reason (struct tls_multi *multi, const char *client_reason) +{ + if (multi->client_reason) + { + free (multi->client_reason); + multi->client_reason = NULL; + } + if (client_reason && strlen (client_reason)) + /* FIXME: Last alloc will never be freed */ + multi->client_reason = string_alloc (client_reason, NULL); +} + +static inline unsigned int +man_def_auth_test (const struct key_state *ks) +{ + if (management_enable_def_auth (management)) + return ks->mda_status; + else + return ACF_DISABLED; +} +#endif + +#ifdef PLUGIN_DEF_AUTH + +/* + * auth_control_file functions + */ + +void +key_state_rm_auth_control_file (struct key_state *ks) +{ + if (ks && ks->auth_control_file) + { + platform_unlink (ks->auth_control_file); + free (ks->auth_control_file); + ks->auth_control_file = NULL; + } +} + +static void +key_state_gen_auth_control_file (struct key_state *ks, const struct tls_options *opt) +{ + struct gc_arena gc = gc_new (); + const char *acf; + + key_state_rm_auth_control_file (ks); + acf = create_temp_file (opt->tmp_dir, "acf", &gc); + if (acf) { + ks->auth_control_file = string_alloc (acf, NULL); + setenv_str (opt->es, "auth_control_file", ks->auth_control_file); + } /* FIXME: Should have better error handling? */ + + gc_free (&gc); +} + +static unsigned int +key_state_test_auth_control_file (struct key_state *ks) +{ + if (ks && ks->auth_control_file) + { + unsigned int ret = ks->auth_control_status; + if (ret == ACF_UNDEFINED) + { + FILE *fp = fopen (ks->auth_control_file, "r"); + if (fp) + { + const int c = fgetc (fp); + if (c == '1') + ret = ACF_SUCCEEDED; + else if (c == '0') + ret = ACF_FAILED; + fclose (fp); + ks->auth_control_status = ret; + } + } + return ret; + } + return ACF_DISABLED; +} + +#endif + +/* + * Return current session authentication state. Return + * value is TLS_AUTHENTICATION_x. + */ + +int +tls_authentication_status (struct tls_multi *multi, const int latency) +{ + bool deferred = false; + bool success = false; + bool active = false; + +#ifdef ENABLE_DEF_AUTH + static const unsigned char acf_merge[] = + { + ACF_UNDEFINED, /* s1=ACF_UNDEFINED s2=ACF_UNDEFINED */ + ACF_UNDEFINED, /* s1=ACF_UNDEFINED s2=ACF_SUCCEEDED */ + ACF_UNDEFINED, /* s1=ACF_UNDEFINED s2=ACF_DISABLED */ + ACF_FAILED, /* s1=ACF_UNDEFINED s2=ACF_FAILED */ + ACF_UNDEFINED, /* s1=ACF_SUCCEEDED s2=ACF_UNDEFINED */ + ACF_SUCCEEDED, /* s1=ACF_SUCCEEDED s2=ACF_SUCCEEDED */ + ACF_SUCCEEDED, /* s1=ACF_SUCCEEDED s2=ACF_DISABLED */ + ACF_FAILED, /* s1=ACF_SUCCEEDED s2=ACF_FAILED */ + ACF_UNDEFINED, /* s1=ACF_DISABLED s2=ACF_UNDEFINED */ + ACF_SUCCEEDED, /* s1=ACF_DISABLED s2=ACF_SUCCEEDED */ + ACF_DISABLED, /* s1=ACF_DISABLED s2=ACF_DISABLED */ + ACF_FAILED, /* s1=ACF_DISABLED s2=ACF_FAILED */ + ACF_FAILED, /* s1=ACF_FAILED s2=ACF_UNDEFINED */ + ACF_FAILED, /* s1=ACF_FAILED s2=ACF_SUCCEEDED */ + ACF_FAILED, /* s1=ACF_FAILED s2=ACF_DISABLED */ + ACF_FAILED /* s1=ACF_FAILED s2=ACF_FAILED */ + }; +#endif /* ENABLE_DEF_AUTH */ + + if (multi) + { + int i; + +#ifdef ENABLE_DEF_AUTH + if (latency && multi->tas_last && multi->tas_last + latency >= now) + return TLS_AUTHENTICATION_UNDEFINED; + multi->tas_last = now; +#endif /* ENABLE_DEF_AUTH */ + + for (i = 0; i < KEY_SCAN_SIZE; ++i) + { + struct key_state *ks = multi->key_scan[i]; + if (DECRYPT_KEY_ENABLED (multi, ks)) + { + active = true; + if (ks->authenticated) + { +#ifdef ENABLE_DEF_AUTH + unsigned int s1 = ACF_DISABLED; + unsigned int s2 = ACF_DISABLED; +#ifdef PLUGIN_DEF_AUTH + s1 = key_state_test_auth_control_file (ks); +#endif /* PLUGIN_DEF_AUTH */ +#ifdef MANAGEMENT_DEF_AUTH + s2 = man_def_auth_test (ks); +#endif /* MANAGEMENT_DEF_AUTH */ + ASSERT (s1 < 4 && s2 < 4); + switch (acf_merge[(s1<<2) + s2]) + { + case ACF_SUCCEEDED: + case ACF_DISABLED: + success = true; + ks->auth_deferred = false; + break; + case ACF_UNDEFINED: + if (now < ks->auth_deferred_expire) + deferred = true; + break; + case ACF_FAILED: + ks->authenticated = false; + break; + default: + ASSERT (0); + } +#else /* !ENABLE_DEF_AUTH */ + success = true; +#endif /* ENABLE_DEF_AUTH */ + } + } + } + } + +#if 0 + dmsg (D_TLS_ERRORS, "TAS: a=%d s=%d d=%d", active, success, deferred); +#endif + + if (success) + return TLS_AUTHENTICATION_SUCCEEDED; + else if (!active || deferred) + return TLS_AUTHENTICATION_DEFERRED; + else + return TLS_AUTHENTICATION_FAILED; +} + +#ifdef MANAGEMENT_DEF_AUTH +/* + * For deferred auth, this is where the management interface calls (on server) + * to indicate auth failure/success. + */ +bool +tls_authenticate_key (struct tls_multi *multi, const unsigned int mda_key_id, const bool auth, const char *client_reason) +{ + bool ret = false; + if (multi) + { + int i; + man_def_auth_set_client_reason (multi, client_reason); + for (i = 0; i < KEY_SCAN_SIZE; ++i) + { + struct key_state *ks = multi->key_scan[i]; + if (ks->mda_key_id == mda_key_id) + { + ks->mda_status = auth ? ACF_SUCCEEDED : ACF_FAILED; + ret = true; + } + } + } + return ret; +} +#endif + + +/* **************************************************************************** + * Functions to verify username and password + * + * Authenticate a client using username/password. + * Runs on server. + * + * If you want to add new authentication methods, + * this is the place to start. + *************************************************************************** */ + +/* + * Verify the user name and password using a script + */ +static bool +verify_user_pass_script (struct tls_session *session, const struct user_pass *up) +{ + struct gc_arena gc = gc_new (); + struct argv argv = argv_new (); + const char *tmp_file = ""; + bool ret = false; + + /* Is username defined? */ + if ((session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL) || 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_file (session->opt->tmp_dir, "up", &gc); + if( tmp_file ) { + 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 { + msg (D_TLS_ERRORS, "TLS Auth Error: could not create write " + "username/password to temp file"); + } + } + 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 */ + argv_printf (&argv, "%sc %s", session->opt->auth_user_pass_verify_script, tmp_file); + + /* call command */ + ret = openvpn_run_script (&argv, session->opt->es, 0, + "--auth-user-pass-verify"); + + 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 (tmp_file && strlen (tmp_file) > 0) + platform_unlink (tmp_file); + + argv_reset (&argv); + gc_free (&gc); + return ret; +} + +/* + * Verify the username and password using a plugin + */ +static int +verify_user_pass_plugin (struct tls_session *session, const struct user_pass *up, const char *raw_username) +{ + int retval = OPENVPN_PLUGIN_FUNC_ERROR; + struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */ + + /* Is username defined? */ + if ((session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL) || strlen (up->username)) + { + /* set username/password in private env space */ + setenv_str (session->opt->es, "username", (raw_username ? raw_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); + +#ifdef PLUGIN_DEF_AUTH + /* generate filename for deferred auth control file */ + key_state_gen_auth_control_file (ks, session->opt); +#endif + + /* call command */ + retval = plugin_call (session->opt->plugins, OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY, NULL, NULL, session->opt->es); + +#ifdef PLUGIN_DEF_AUTH + /* purge auth control filename (and file itself) for non-deferred returns */ + if (retval != OPENVPN_PLUGIN_FUNC_DEFERRED) + key_state_rm_auth_control_file (ks); +#endif + + setenv_del (session->opt->es, "password"); + if (raw_username) + setenv_str (session->opt->es, "username", up->username); + } + else + { + msg (D_TLS_ERRORS, "TLS Auth Error (verify_user_pass_plugin): peer provided a blank username"); + } + + return retval; +} + + +#ifdef MANAGEMENT_DEF_AUTH +/* + * MANAGEMENT_DEF_AUTH internal ssl_verify.c status codes + */ +#define KMDA_ERROR 0 +#define KMDA_SUCCESS 1 +#define KMDA_UNDEF 2 +#define KMDA_DEF 3 + +static int +verify_user_pass_management (struct tls_session *session, const struct user_pass *up, const char *raw_username) +{ + int retval = KMDA_ERROR; + struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */ + + /* Is username defined? */ + if ((session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL) || strlen (up->username)) + { + /* set username/password in private env space */ + setenv_str (session->opt->es, "username", (raw_username ? raw_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); + + if (management) + management_notify_client_needing_auth (management, ks->mda_key_id, session->opt->mda_context, session->opt->es); + + setenv_del (session->opt->es, "password"); + if (raw_username) + setenv_str (session->opt->es, "username", up->username); + + retval = KMDA_SUCCESS; + } + else + { + msg (D_TLS_ERRORS, "TLS Auth Error (verify_user_pass_management): peer provided a blank username"); + } + + return retval; +} +#endif + +/* + * Main username/password verification entry point + */ +void +verify_user_pass(struct user_pass *up, struct tls_multi *multi, + struct tls_session *session) +{ + int s1 = OPENVPN_PLUGIN_FUNC_SUCCESS; + bool s2 = true; + struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */ + + struct gc_arena gc = gc_new (); + char *raw_username = NULL; + +#ifdef MANAGEMENT_DEF_AUTH + int man_def_auth = KMDA_UNDEF; + + if (management_enable_def_auth (management)) + man_def_auth = KMDA_DEF; +#endif + + /* + * Preserve the raw username before string_mod remapping, for plugins + * and management clients when in --compat-names mode + */ + if (compat_flag (COMPAT_FLAG_QUERY | COMPAT_NAMES)) + { + 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_remap_name (up->username, COMMON_NAME_CHAR_CLASS); + string_mod (up->password, CC_PRINT, CC_CRLF, '_'); + + /* call plugin(s) and/or script */ +#ifdef MANAGEMENT_DEF_AUTH + if (man_def_auth == KMDA_DEF) + man_def_auth = verify_user_pass_management (session, up, raw_username); +#endif + 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); + + /* check sizing of username if it will become our common name */ + if ((session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME) && strlen (up->username) >= TLS_USERNAME_LEN) + { + msg (D_TLS_ERRORS, "TLS Auth Error: --username-as-common name specified and username is longer than the maximum permitted Common Name length of %d characters", TLS_USERNAME_LEN); + s1 = OPENVPN_PLUGIN_FUNC_ERROR; + } + + /* auth succeeded? */ + if ((s1 == OPENVPN_PLUGIN_FUNC_SUCCESS +#ifdef PLUGIN_DEF_AUTH + || s1 == OPENVPN_PLUGIN_FUNC_DEFERRED +#endif + ) && s2 +#ifdef MANAGEMENT_DEF_AUTH + && man_def_auth != KMDA_ERROR +#endif + && tls_lock_username (multi, up->username)) + { + ks->authenticated = true; +#ifdef PLUGIN_DEF_AUTH + if (s1 == OPENVPN_PLUGIN_FUNC_DEFERRED) + ks->auth_deferred = true; +#endif +#ifdef MANAGEMENT_DEF_AUTH + if (man_def_auth != KMDA_UNDEF) + ks->auth_deferred = true; +#endif + if ((session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME)) + set_common_name (session, up->username); +#ifdef ENABLE_DEF_AUTH + msg (D_HANDSHAKE, "TLS: Username/Password authentication %s for username '%s' %s", + ks->auth_deferred ? "deferred" : "succeeded", + up->username, + (session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME) ? "[CN SET]" : ""); +#else + msg (D_HANDSHAKE, "TLS: Username/Password authentication %s for username '%s' %s", + "succeeded", + up->username, + (session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME) ? "[CN SET]" : ""); +#endif + } + else + { + msg (D_TLS_ERRORS, "TLS Auth Error: Auth Username/Password verification failed for peer"); + } + + gc_free (&gc); +} + +void +verify_final_auth_checks(struct tls_multi *multi, struct tls_session *session) +{ + struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */ + + /* 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); + } + } + + /* Don't allow the cert hashes to change once they have been locked */ + if (ks->authenticated && multi->locked_cert_hash_set) + { + const struct cert_hash_set *chs = session->cert_hash_set; + if (chs && !cert_hash_compare (chs, multi->locked_cert_hash_set)) + { + msg (D_TLS_ERRORS, "TLS Auth Error: TLS object CN=%s client-provided SSL certs unexpectedly changed during mid-session reauth", + session->common_name); + + /* disable the tunnel */ + tls_deauthenticate (multi); + } + } + + /* verify --client-config-dir based authentication */ + if (ks->authenticated && session->opt->client_config_dir_exclusive) + { + struct gc_arena gc = gc_new (); + + 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"); + } + + gc_free (&gc); + } +} +#endif /* defined(ENABLE_CRYPTO) && defined(ENABLE_SSL) */ |