/* Written by Simon Josefsson . * Copyright (c) 2006-2014 Yubico AB * Copyright (c) 2011 Tollef Fog Heen * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #include #include #include "util.h" #include "drop_privs.h" #include #if HAVE_CR /* for yubikey_hex_encode */ #include /* for yubikey pbkdf2*/ #include #endif /* HAVE_CR */ /* Libtool defines PIC for shared objects */ #ifndef PIC #define PAM_STATIC #endif /* These #defines must be present according to PAM documentation. */ #define PAM_SM_AUTH #ifdef HAVE_SECURITY_PAM_APPL_H #include #endif #ifdef HAVE_SECURITY_PAM_MODULES_H #include #endif #ifdef HAVE_LIBLDAP /* Some functions like ldap_init, ldap_simple_bind_s, ldap_unbind are deprecated but still available. We will drop support for 'ldapserver' (in favour of 'ldap_uri' and update to using the new functions instead soon. */ #define LDAP_DEPRECATED 1 #include #define PORT_NUMBER LDAP_PORT #endif #ifndef PAM_EXTERN #ifdef PAM_STATIC #define PAM_EXTERN static #else #define PAM_EXTERN extern #endif #endif #define TOKEN_OTP_LEN 32u #define MAX_TOKEN_ID_LEN 16u #define DEFAULT_TOKEN_ID_LEN 12u #define TMPFILE_SUFFIX ".XXXXXX" enum key_mode { CHRESP, CLIENT }; struct cfg { unsigned int client_id; const char *client_key; int debug; int alwaysok; int verbose_otp; int try_first_pass; int use_first_pass; const char *auth_file; const char *capath; const char *cainfo; const char *proxy; const char *url; const char *urllist; const char *ldapserver; const char *ldap_uri; const char *ldap_bind_user; const char *ldap_bind_password; const char *ldap_filter; const char *ldap_cacertfile; const char *ldapdn; const char *user_attr; const char *yubi_attr; const char *yubi_attr_prefix; unsigned int token_id_length; enum key_mode mode; const char *chalresp_path; }; #ifdef DBG #undef DBG #endif #define DBG(x) if (cfg->debug) { D(x); } /* * Authorize authenticated OTP_ID for login as USERNAME using * AUTHFILE. Return -2 if the user is unknown, -1 if the OTP_ID does not match, 0 on internal failures, otherwise success. */ static int authorize_user_token (struct cfg *cfg, const char *username, const char *otp_id, pam_handle_t *pamh) { int retval; if (cfg->auth_file) { /* Administrator had configured the file and specified is name as an argument for this module. */ DBG (("Using system-wide auth_file %s", cfg->auth_file)); retval = check_user_token (cfg->auth_file, username, otp_id, cfg->debug); } else { char *userfile = NULL; struct passwd *p; PAM_MODUTIL_DEF_PRIVS(privs); #ifdef HAVE_PAM_MODUTIL_GETPWNAM p = pam_modutil_getpwnam (pamh, username); #else p = getpwnam (username); #endif if (p == NULL) { DBG (("getpwnam: %s", strerror(errno))); return 0; } /* Getting file from user home directory ..... i.e. ~/.yubico/authorized_yubikeys */ if (! get_user_cfgfile_path (NULL, "authorized_yubikeys", p, &userfile)) { D (("Failed figuring out per-user cfgfile")); return 0; } DBG (("Dropping privileges")); if(pam_modutil_drop_priv(pamh, &privs, p)) { DBG (("could not drop privileges")); retval = 0; goto free_out; } retval = check_user_token (userfile, username, otp_id, cfg->debug); if(pam_modutil_regain_priv(pamh, &privs)) { DBG (("could not restore privileges")); retval = 0; goto free_out; } free_out: free (userfile); } return retval; } /* * This function will look in ldap id the token correspond to the * requested user. It will returns 0 for failure and 1 for success. * * ldaps is only supported for ldap_uri based connections. * ldap_cacertfile usually needs to be set for this to work. * * ldap serve can be on a remote host. * * You need the following parameters in you pam config: * ldapserver= OR ldap_uri= * ldapdn= * user_attr= * yubi_attr= * * If using ldap_uri, you can specify multiple failover hosts * eg. * ldap_uri=ldaps://host1.fqdn.example.com,ldaps://host2.fqdn.example.com */ static int authorize_user_token_ldap (struct cfg *cfg, const char *user, const char *token_id) { int retval = 0; #ifdef HAVE_LIBLDAP /* LDAPv2 is historical -- RFC3494. */ int protocol = LDAP_VERSION3; size_t yubi_attr_prefix_len = 0; LDAP *ld = NULL; LDAPMessage *result = NULL, *e; BerElement *ber; char *a; char *attrs[2] = {NULL, NULL}; struct berval **vals; int rc; size_t i; char *filter = NULL; char *find = NULL; int scope = LDAP_SCOPE_BASE; #endif DBG(("called")); #ifdef HAVE_LIBLDAP if (cfg->yubi_attr == NULL) { DBG (("Trying to look up user to YubiKey mapping in LDAP, but yubi_attr not set!")); return 0; } if (cfg->user_attr && cfg->ldapdn == NULL) { DBG (("Trying to look up user to YubiKey mapping in LDAP, user_attr set but ldapdn not set!")); return 0; } /* Get a handle to an LDAP connection. */ if (cfg->ldap_uri) { rc = ldap_initialize (&ld, cfg->ldap_uri); if (rc != LDAP_SUCCESS) { DBG (("ldap_initialize: %s", ldap_err2string (rc))); retval = 0; goto done; } } else { if ((ld = ldap_init (cfg->ldapserver, PORT_NUMBER)) == NULL) { DBG (("ldap_init")); retval = 0; goto done; } } ldap_set_option(ld, LDAP_OPT_REFERRALS, LDAP_OPT_OFF); ldap_set_option (ld, LDAP_OPT_PROTOCOL_VERSION, &protocol); if (cfg->ldap_uri && cfg->ldap_cacertfile) { /* Set CA CERTFILE. This makes ldaps work when using ldap_uri */ ldap_set_option (0, LDAP_OPT_X_TLS_CACERTFILE, cfg->ldap_cacertfile); } /* Bind anonymously to the LDAP server. */ if (cfg->ldap_bind_user && cfg->ldap_bind_password) { DBG (("try bind with: %s:[%s]", cfg->ldap_bind_user, cfg->ldap_bind_password)); rc = ldap_simple_bind_s (ld, cfg->ldap_bind_user, cfg->ldap_bind_password); } else { DBG (("try bind anonymous")); rc = ldap_simple_bind_s (ld, NULL, NULL); } if (rc != LDAP_SUCCESS) { DBG (("ldap_simple_bind_s: %s", ldap_err2string (rc))); retval = 0; goto done; } /* Allocation of memory for search strings depending on input size */ if (cfg->user_attr && cfg->yubi_attr && cfg->ldapdn) { i = (strlen(cfg->user_attr) + strlen(cfg->ldapdn) + strlen(user) + 3) * sizeof(char); if ((find = malloc(i)) == NULL) { DBG (("Failed allocating %zu bytes", i)); retval = 0; goto done; } sprintf (find, "%s=%s,%s", cfg->user_attr, user, cfg->ldapdn); filter = NULL; } else if (cfg->ldapdn) { find = strdup(cfg->ldapdn); /* allow free later */ } if (cfg->ldap_filter) { filter = filter_printf(cfg->ldap_filter, user); scope = LDAP_SCOPE_SUBTREE; } attrs[0] = (char *) cfg->yubi_attr; DBG(("LDAP : look up object base='%s' filter='%s', ask for attribute '%s'", find, filter ? filter:"(null)", cfg->yubi_attr)); /* Search for the entry. */ if ((rc = ldap_search_ext_s (ld, find, scope, filter, attrs, 0, NULL, NULL, LDAP_NO_LIMIT, LDAP_NO_LIMIT, &result)) != LDAP_SUCCESS) { DBG (("ldap_search_ext_s: %s", ldap_err2string (rc))); retval = 0; goto done; } e = ldap_first_entry (ld, result); if (e == NULL) { DBG (("No result from LDAP search")); retval = -2; } else { retval = -1; /* Iterate through each returned attribute. */ for (a = ldap_first_attribute (ld, e, &ber); a != NULL; a = ldap_next_attribute (ld, e, ber)) { if ((vals = ldap_get_values_len (ld, e, a)) != NULL) { yubi_attr_prefix_len = cfg->yubi_attr_prefix ? strlen(cfg->yubi_attr_prefix) : 0; /* Compare each value for the attribute against the token id. */ for (i = 0; vals[i] != NULL; i++) { DBG(("LDAP : Found %i values - checking if any of them match '%s:%s:%s'", ldap_count_values_len(vals), vals[i]->bv_val, cfg->yubi_attr_prefix ? cfg->yubi_attr_prefix : "", token_id)); /* Only values containing this prefix are considered. */ if ((!cfg->yubi_attr_prefix || !strncmp (cfg->yubi_attr_prefix, vals[i]->bv_val, yubi_attr_prefix_len))) { if(!strncmp (token_id, vals[i]->bv_val + yubi_attr_prefix_len, strlen (token_id))) { DBG (("Token Found :: %s", vals[i]->bv_val)); retval = 1; } } } ldap_value_free_len (vals); } ldap_memfree (a); } if (ber != NULL) ber_free (ber, 0); } done: if (result != NULL) ldap_msgfree (result); if (ld != NULL) ldap_unbind (ld); /* free memory allocated for search strings */ if (find != NULL) free(find); if (filter != NULL) free(filter); #else DBG (("Trying to use LDAP, but this function is not compiled in pam_yubico!!")); DBG (("Install libldap-dev and then recompile pam_yubico.")); #endif return retval; } #if HAVE_CR static int display_error(pam_handle_t *pamh, const char *message) { struct pam_conv *conv; const struct pam_message *pmsg[1]; struct pam_message msg[1]; struct pam_response *resp = NULL; int retval; retval = pam_get_item (pamh, PAM_CONV, (const void **) &conv); if (retval != PAM_SUCCESS) { D(("get conv returned error: %s", pam_strerror (pamh, retval))); return retval; } if(!conv || !conv->conv){ D(("conv() function invalid")); return PAM_CONV_ERR; } pmsg[0] = &msg[0]; msg[0].msg = (char *) message; /* on some systems, pam_message.msg isn't const */ msg[0].msg_style = PAM_ERROR_MSG; retval = conv->conv(1, pmsg, &resp, conv->appdata_ptr); if (retval != PAM_SUCCESS) { D(("conv returned error: %s", pam_strerror (pamh, retval))); return retval; } if (resp) { D(("conv returned: '%s'", resp->resp)); if (resp->resp) free (resp->resp); free (resp); } return retval; } #endif /* HAVE_CR */ #if HAVE_CR static int do_challenge_response(pam_handle_t *pamh, struct cfg *cfg, const char *username) { char *userfile = NULL, *tmpfile = NULL; FILE *f = NULL; char buf[CR_RESPONSE_SIZE + 16], response_hex[CR_RESPONSE_SIZE * 2 + 1]; int ret, fd; unsigned int response_len = 0; YK_KEY *yk = NULL; CR_STATE state; const char *errstr = NULL; struct passwd *p; struct stat st; /* we must declare two sepparate privs structures as they can't be reused */ PAM_MODUTIL_DEF_PRIVS(privs); PAM_MODUTIL_DEF_PRIVS(privs2); ret = PAM_AUTH_ERR; if (! init_yubikey(&yk)) { DBG(("Failed initializing YubiKey")); goto out; } if (! check_firmware_version(yk, false, true)) { DBG(("YubiKey does not support Challenge-Response (version 2.2 required)")); goto out; } #ifdef HAVE_PAM_MODUTIL_GETPWNAM p = pam_modutil_getpwnam (pamh, username); #else p = getpwnam (username); #endif if (p == NULL) { DBG (("getpwnam: %s", strerror(errno))); goto out; } if (! get_user_challenge_file (yk, cfg->chalresp_path, p, &userfile)) { DBG(("Failed getting user challenge file for user %s", username)); goto out; } DBG(("Loading challenge from file %s", userfile)); /* Drop privileges before opening user file (if we're not using system-wide dir). */ if (!cfg->chalresp_path) { if (pam_modutil_drop_priv(pamh, &privs, p)) { DBG (("could not drop privileges")); goto out; } } fd = open(userfile, O_RDONLY, 0); if (fd < 0) { DBG (("Cannot open file: %s (%s)", userfile, strerror(errno))); goto restpriv_out; } if (fstat(fd, &st) < 0) { DBG (("Cannot stat file: %s (%s)", userfile, strerror(errno))); close(fd); goto restpriv_out; } if (!S_ISREG(st.st_mode)) { DBG (("%s is not a regular file", userfile)); close(fd); goto restpriv_out; } f = fdopen(fd, "r"); if (f == NULL) { DBG (("fdopen: %s", strerror(errno))); close(fd); goto restpriv_out; } if (! load_chalresp_state(f, &state, cfg->debug)) goto restpriv_out; if (fclose(f) < 0) { f = NULL; goto restpriv_out; } f = NULL; if (!cfg->chalresp_path) { if (pam_modutil_regain_priv(pamh, &privs)) { DBG (("could not restore privileges")); goto out; } } if (! challenge_response(yk, state.slot, state.challenge, state.challenge_len, true, true, false, buf, sizeof(buf), &response_len)) { DBG(("Challenge-response FAILED")); goto out; } /* * Check YubiKey response against the expected response */ yubikey_hex_encode(response_hex, buf, response_len); if(state.salt_len > 0) { /* the expected response has gone through pbkdf2 */ YK_PRF_METHOD prf_method = {20, yk_hmac_sha1}; yk_pbkdf2(response_hex, (unsigned char*)state.salt, state.salt_len, state.iterations, (unsigned char*)buf, response_len, &prf_method); } if (memcmp(buf, state.response, state.response_len) == 0) { ret = PAM_SUCCESS; } else { DBG(("Unexpected C/R response : %s", response_hex)); goto out; } DBG(("Got the expected response, generating new challenge (%u bytes).", CR_CHALLENGE_SIZE)); errstr = "Error generating new challenge, please check syslog or contact your system administrator"; if (generate_random(state.challenge, sizeof(state.challenge))) { DBG(("Failed generating new challenge!")); goto out; } errstr = "Error communicating with Yubikey, please check syslog or contact your system administrator"; if (! challenge_response(yk, state.slot, state.challenge, CR_CHALLENGE_SIZE, true, true, false, buf, sizeof(buf), &response_len)) { DBG(("Second challenge-response FAILED")); goto out; } /* There is a bug that makes the YubiKey 2.2 send the same response for all challenges unless HMAC_LT64 is set, check for that here */ if (memcmp(buf, state.response, state.response_len) == 0) { errstr = "Same response for second challenge, YubiKey should be reconfigured with the option HMAC_LT64"; goto out; } /* the yk_* functions leave 'junk' in errno */ errno = 0; /* * Write the challenge and response we will expect the next time to the state file. */ if (response_len > sizeof(state.response)) { DBG(("Got too long response ??? (%u/%zu)", response_len, sizeof(state.response))); goto out; } memcpy (state.response, buf, response_len); state.response_len = response_len; /* point to the fresh privs structure.. */ privs = privs2; /* Drop privileges before creating new challenge file. */ if (!cfg->chalresp_path) { if (pam_modutil_drop_priv(pamh, &privs, p)) { DBG (("could not drop privileges")); goto out; } } /* Write out the new file */ tmpfile = malloc(strlen(userfile) + 1 + strlen(TMPFILE_SUFFIX)); if (! tmpfile) goto restpriv_out; strcpy(tmpfile, userfile); strcat(tmpfile, TMPFILE_SUFFIX); fd = mkstemp(tmpfile); if (fd < 0) { DBG (("Cannot open file: %s (%s)", tmpfile, strerror(errno))); goto restpriv_out; } if (fchmod (fd, S_IRUSR | S_IWUSR) != 0) { DBG (("could not set correct file permissions")); goto restpriv_out; } f = fdopen(fd, "w"); if (! f) { close(fd); goto restpriv_out; } errstr = "Error updating Yubikey challenge, please check syslog or contact your system administrator"; if (! write_chalresp_state (f, &state)) goto out; if (fclose(f) < 0) { f = NULL; goto restpriv_out; } f = NULL; if (rename(tmpfile, userfile) < 0) { goto restpriv_out; } DBG(("Challenge-response success!")); errstr = NULL; errno = 0; yk_errno = 0; restpriv_out: if (!cfg->chalresp_path) { if (pam_modutil_regain_priv(pamh, &privs)) { DBG (("could not restore privileges")); } } out: if (yk_errno) { if (yk_errno == YK_EUSBERR) { syslog(LOG_ERR, "USB error: %s", yk_usb_strerror()); DBG(("USB error: %s", yk_usb_strerror())); } else { syslog(LOG_ERR, "Yubikey core error: %s", yk_strerror(yk_errno)); DBG(("Yubikey core error: %s", yk_strerror(yk_errno))); } } if (errstr) display_error(pamh, errstr); if (errno) { syslog(LOG_ERR, "Challenge response failed: %s", strerror(errno)); DBG(("Challenge response failed: %s", strerror(errno))); } if (yk) yk_close_key(yk); yk_release(); if (f) fclose(f); free(userfile); free(tmpfile); return ret; } #endif /* HAVE_CR */ static void parse_cfg (int flags, int argc, const char **argv, struct cfg *cfg) { int i; memset (cfg, 0, sizeof(struct cfg)); cfg->client_id = 0; cfg->token_id_length = DEFAULT_TOKEN_ID_LEN; cfg->mode = CLIENT; for (i = 0; i < argc; i++) { if (strncmp (argv[i], "id=", 3) == 0) sscanf (argv[i], "id=%d", &cfg->client_id); if (strncmp (argv[i], "key=", 4) == 0) cfg->client_key = argv[i] + 4; if (strcmp (argv[i], "debug") == 0) cfg->debug = 1; if (strcmp (argv[i], "alwaysok") == 0) cfg->alwaysok = 1; if (strcmp (argv[i], "verbose_otp") == 0) cfg->verbose_otp = 1; if (strcmp (argv[i], "try_first_pass") == 0) cfg->try_first_pass = 1; if (strcmp (argv[i], "use_first_pass") == 0) cfg->use_first_pass = 1; if (strncmp (argv[i], "authfile=", 9) == 0) cfg->auth_file = argv[i] + 9; if (strncmp (argv[i], "capath=", 7) == 0) cfg->capath = argv[i] + 7; if (strncmp (argv[i], "cainfo=", 7) == 0) cfg->cainfo = argv[i] + 7; if (strncmp (argv[i], "proxy=", 6) == 0) cfg->proxy = argv[i] + 6; if (strncmp (argv[i], "url=", 4) == 0) cfg->url = argv[i] + 4; if (strncmp (argv[i], "urllist=", 8) == 0) cfg->urllist = argv[i] + 8; if (strncmp (argv[i], "ldapserver=", 11) == 0) cfg->ldapserver = argv[i] + 11; if (strncmp (argv[i], "ldap_uri=", 9) == 0) cfg->ldap_uri = argv[i] + 9; if (strncmp (argv[i], "ldap_bind_user=", 15) == 0) cfg->ldap_bind_user = argv[i] + 15; if (strncmp (argv[i], "ldap_bind_password=", 19) == 0) cfg->ldap_bind_password = argv[i] + 19; if (strncmp (argv[i], "ldap_filter=", 12) == 0) cfg->ldap_filter = argv[i] + 12; if (strncmp (argv[i], "ldap_cacertfile=", 16) == 0) cfg->ldap_cacertfile = argv[i] + 16; if (strncmp (argv[i], "ldapdn=", 7) == 0) cfg->ldapdn = argv[i] + 7; if (strncmp (argv[i], "user_attr=", 10) == 0) cfg->user_attr = argv[i] + 10; if (strncmp (argv[i], "yubi_attr=", 10) == 0) cfg->yubi_attr = argv[i] + 10; if (strncmp (argv[i], "yubi_attr_prefix=", 17) == 0) cfg->yubi_attr_prefix = argv[i] + 17; if (strncmp (argv[i], "token_id_length=", 16) == 0) sscanf (argv[i], "token_id_length=%u", &cfg->token_id_length); if (strcmp (argv[i], "mode=challenge-response") == 0) cfg->mode = CHRESP; if (strcmp (argv[i], "mode=client") == 0) cfg->mode = CLIENT; if (strncmp (argv[i], "chalresp_path=", 14) == 0) cfg->chalresp_path = argv[i] + 14; } if (cfg->debug) { D (("called.")); D (("flags %d argc %d", flags, argc)); for (i = 0; i < argc; i++) D (("argv[%d]=%s", i, argv[i])); D (("id=%u", cfg->client_id)); D (("key=%s", cfg->client_key ? cfg->client_key : "(null)")); D (("debug=%d", cfg->debug)); D (("alwaysok=%d", cfg->alwaysok)); D (("verbose_otp=%d", cfg->verbose_otp)); D (("try_first_pass=%d", cfg->try_first_pass)); D (("use_first_pass=%d", cfg->use_first_pass)); D (("authfile=%s", cfg->auth_file ? cfg->auth_file : "(null)")); D (("ldapserver=%s", cfg->ldapserver ? cfg->ldapserver : "(null)")); D (("ldap_uri=%s", cfg->ldap_uri ? cfg->ldap_uri : "(null)")); D (("ldap_bind_user=%s", cfg->ldap_bind_user ? cfg->ldap_bind_user : "(null)")); D (("ldap_bind_password=%s", cfg->ldap_bind_password ? cfg->ldap_bind_password : "(null)")); D (("ldap_filter=%s", cfg->ldap_filter ? cfg->ldap_filter : "(null)")); D (("ldap_cacertfile=%s", cfg->ldap_cacertfile ? cfg->ldap_cacertfile : "(null)")); D (("ldapdn=%s", cfg->ldapdn ? cfg->ldapdn : "(null)")); D (("user_attr=%s", cfg->user_attr ? cfg->user_attr : "(null)")); D (("yubi_attr=%s", cfg->yubi_attr ? cfg->yubi_attr : "(null)")); D (("yubi_attr_prefix=%s", cfg->yubi_attr_prefix ? cfg->yubi_attr_prefix : "(null)")); D (("url=%s", cfg->url ? cfg->url : "(null)")); D (("urllist=%s", cfg->urllist ? cfg->urllist : "(null)")); D (("capath=%s", cfg->capath ? cfg->capath : "(null)")); D (("cainfo=%s", cfg->cainfo ? cfg->cainfo : "(null)")); D (("proxy=%s", cfg->proxy ? cfg->proxy : "(null)")); D (("token_id_length=%d", cfg->token_id_length)); D (("mode=%s", cfg->mode == CLIENT ? "client" : "chresp" )); D (("chalresp_path=%s", cfg->chalresp_path ? cfg->chalresp_path : "(null)")); } } PAM_EXTERN int pam_sm_authenticate (pam_handle_t * pamh, int flags, int argc, const char **argv) { int retval, rc; const char *user = NULL; const char *password = NULL; char otp[MAX_TOKEN_ID_LEN + TOKEN_OTP_LEN + 1] = { 0 }; char otp_id[MAX_TOKEN_ID_LEN + 1] = { 0 }; size_t password_len = 0; int skip_bytes = 0; int valid_token = 0; struct pam_conv *conv; const struct pam_message *pmsg[1]; struct pam_message msg[1] = {{0}}; struct pam_response *resp = NULL; int nargs = 1; ykclient_t *ykc = NULL; struct cfg cfg_st; struct cfg *cfg = &cfg_st; /* for DBG macro */ size_t templates = 0; char *urls[10]; char *tmpurl = NULL; char *onlypasswd = NULL; parse_cfg (flags, argc, argv, cfg); DBG (("pam_yubico version: %s", VERSION)); if (cfg->token_id_length > MAX_TOKEN_ID_LEN) { DBG (("configuration error: token_id_length too long. Maximum acceptable value : %u", MAX_TOKEN_ID_LEN)); retval = PAM_AUTHINFO_UNAVAIL; goto done; } retval = pam_get_user (pamh, &user, NULL); if (retval != PAM_SUCCESS) { DBG (("get user returned error: %s", pam_strerror (pamh, retval))); goto done; } DBG (("get user returned: %s", user)); if (cfg->mode == CHRESP) { #if HAVE_CR return do_challenge_response(pamh, cfg, user); #else DBG (("no support for challenge/response")); retval = PAM_AUTH_ERR; goto done; #endif } if (cfg->try_first_pass || cfg->use_first_pass) { retval = pam_get_item (pamh, PAM_AUTHTOK, (const void **) &password); if (retval != PAM_SUCCESS) { DBG (("get password returned error: %s", pam_strerror (pamh, retval))); goto done; } DBG (("get password returned: %s", password)); } if (cfg->use_first_pass && password == NULL) { DBG (("use_first_pass set and no password, giving up")); retval = PAM_AUTH_ERR; goto done; } if(ykclient_global_init() != YKCLIENT_OK) { DBG (("Failed initializing ykclient library")); retval = PAM_AUTHINFO_UNAVAIL; goto done; } rc = ykclient_init (&ykc); if (rc != YKCLIENT_OK) { DBG (("ykclient_init() failed (%d): %s", rc, ykclient_strerror (rc))); retval = PAM_AUTHINFO_UNAVAIL; goto done; } rc = ykclient_set_client_b64 (ykc, cfg->client_id, cfg->client_key); if (rc != YKCLIENT_OK) { DBG (("ykclient_set_client_b64() failed (%d): %s", rc, ykclient_strerror (rc))); retval = PAM_AUTHINFO_UNAVAIL; goto done; } if (cfg->client_key) ykclient_set_verify_signature (ykc, 1); if (cfg->capath) ykclient_set_ca_path (ykc, cfg->capath); if (cfg->cainfo) ykclient_set_ca_info (ykc, cfg->cainfo); if (cfg->proxy) ykclient_set_proxy (ykc, cfg->proxy); if (cfg->url) { rc = ykclient_set_url_template (ykc, cfg->url); if (rc != YKCLIENT_OK) { DBG (("ykclient_set_url_template() failed (%d): %s", rc, ykclient_strerror (rc))); retval = PAM_AUTHINFO_UNAVAIL; goto done; } } if (cfg->urllist) { char *saveptr = NULL; char *part = NULL; tmpurl = strdup(cfg->urllist); while ((part = strtok_r(templates == 0 ? tmpurl : NULL, ";", &saveptr))) { if(templates == 10) { DBG (("maximum 10 urls supported in list.")); retval = PAM_AUTHINFO_UNAVAIL; goto done; } urls[templates] = strdup(part); templates++; } rc = ykclient_set_url_bases (ykc, templates, (const char **)urls); if (rc != YKCLIENT_OK) { DBG (("ykclient_set_url_bases() failed (%d): %s", rc, ykclient_strerror (rc))); retval = PAM_AUTHINFO_UNAVAIL; goto done; } } if (password == NULL) { retval = pam_get_item (pamh, PAM_CONV, (const void **) &conv); if (retval != PAM_SUCCESS) { DBG (("get conv returned error: %s", pam_strerror (pamh, retval))); goto done; } pmsg[0] = &msg[0]; { #define QUERY_TEMPLATE "YubiKey for `%s': " size_t len = strlen (QUERY_TEMPLATE) + strlen (user); int wrote; msg[0].msg = malloc (len); if (!msg[0].msg) { retval = PAM_BUF_ERR; goto done; } wrote = snprintf ((char *) msg[0].msg, len, QUERY_TEMPLATE, user); if (wrote < 0 || wrote >= len) { retval = PAM_BUF_ERR; goto done; } } msg[0].msg_style = cfg->verbose_otp ? PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF; retval = conv->conv (nargs, pmsg, &resp, conv->appdata_ptr); if (retval != PAM_SUCCESS) { DBG (("conv returned error: %s", pam_strerror (pamh, retval))); goto done; } if (resp->resp == NULL) { DBG (("conv returned NULL passwd?")); retval = PAM_AUTH_ERR; goto done; } DBG (("conv returned %zu bytes", strlen(resp->resp))); password = resp->resp; } password_len = strlen (password); if (password_len < (cfg->token_id_length + TOKEN_OTP_LEN)) { DBG (("OTP too short to be considered : %zu < %u", password_len, (cfg->token_id_length + TOKEN_OTP_LEN))); retval = PAM_AUTH_ERR; goto done; } /* In case the input was systempassword+YubiKeyOTP, we want to skip over "systempassword" when copying the token_id and OTP to separate buffers */ skip_bytes = password_len - (cfg->token_id_length + TOKEN_OTP_LEN); DBG (("Skipping first %i bytes. Length is %zu, token_id set to %u and token OTP always %u.", skip_bytes, password_len, cfg->token_id_length, TOKEN_OTP_LEN)); /* Copy full YubiKey output (public ID + OTP) into otp */ strncpy (otp, password + skip_bytes, sizeof (otp) - 1); /* Copy only public ID into otp_id. Destination buffer is zeroed. */ strncpy (otp_id, password + skip_bytes, cfg->token_id_length); DBG (("OTP: %s ID: %s ", otp, otp_id)); /* user entered their system password followed by generated OTP? */ if (password_len > TOKEN_OTP_LEN + cfg->token_id_length) { onlypasswd = strdup (password); if (! onlypasswd) { retval = PAM_BUF_ERR; goto done; } onlypasswd[password_len - (TOKEN_OTP_LEN + cfg->token_id_length)] = '\0'; DBG (("Extracted a probable system password entered before the OTP - " "setting item PAM_AUTHTOK")); retval = pam_set_item (pamh, PAM_AUTHTOK, onlypasswd); if (retval != PAM_SUCCESS) { DBG (("set_item returned error: %s", pam_strerror (pamh, retval))); goto done; } } else password = NULL; rc = ykclient_request (ykc, otp); DBG (("ykclient return value (%d): %s", rc, ykclient_strerror (rc))); DBG (("ykclient url used: %s", ykclient_get_last_url(ykc))); switch (rc) { case YKCLIENT_OK: break; case YKCLIENT_BAD_OTP: case YKCLIENT_REPLAYED_OTP: retval = PAM_AUTH_ERR; goto done; default: retval = PAM_AUTHINFO_UNAVAIL; goto done; } /* authorize the user with supplied token id */ if (cfg->ldapserver != NULL || cfg->ldap_uri != NULL) valid_token = authorize_user_token_ldap (cfg, user, otp_id); else valid_token = authorize_user_token (cfg, user, otp_id, pamh); switch(valid_token) { case 1: retval = PAM_SUCCESS; break; case 0: DBG (("Internal error while validating user")); retval = PAM_AUTHINFO_UNAVAIL; break; case -1: DBG (("Unauthorized token for this user")); retval = PAM_AUTH_ERR; break; case -2: DBG (("Unknown user")); retval = PAM_USER_UNKNOWN; break; default: DBG (("Unhandled value for token-user validation")) retval = PAM_AUTHINFO_UNAVAIL; } done: if (onlypasswd) free(onlypasswd); if (templates > 0) { size_t i; for(i = 0; i < templates; i++) { free(urls[i]); } } if (tmpurl) free(tmpurl); if (ykc) { ykclient_done (&ykc); ykclient_global_done(); } if (cfg->alwaysok && retval != PAM_SUCCESS) { DBG (("alwaysok needed (otherwise return with %d)", retval)); retval = PAM_SUCCESS; } DBG (("done. [%s]", pam_strerror (pamh, retval))); pam_set_data (pamh, "yubico_setcred_return", (void*)(intptr_t)retval, NULL); if (resp) { if (resp->resp) free (resp->resp); free (resp); } if(msg[0].msg) { free((char*)msg[0].msg); } return retval; } PAM_EXTERN int pam_sm_setcred ( pam_handle_t *pamh __attribute__((unused)), int flags __attribute__((unused)), int argc __attribute__((unused)), const char *argv[] __attribute__((unused))) { return PAM_SUCCESS; } PAM_EXTERN int pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __attribute__((unused)), int argc __attribute__((unused)), const char **argv __attribute__((unused))) { int retval; int rc = pam_get_data(pamh, "yubico_setcred_return", (const void**)&retval); if (rc == PAM_SUCCESS && retval == PAM_SUCCESS) { D (("pam_sm_acct_mgmt returing PAM_SUCCESS")); return PAM_SUCCESS; } D (("pam_sm_acct_mgmt returing PAM_AUTH_ERR:%d", rc)); return PAM_AUTH_ERR; } PAM_EXTERN int pam_sm_open_session( pam_handle_t *pamh __attribute__((unused)), int flags __attribute__((unused)), int argc __attribute__((unused)), const char *argv[] __attribute__((unused))) { D(("pam_sm_open_session")); return (PAM_SUCCESS); } PAM_EXTERN int pam_sm_close_session( pam_handle_t *pamh __attribute__((unused)), int flags __attribute__((unused)), int argc __attribute__((unused)), const char *argv[] __attribute__((unused))) { D(("pam_sm_close_session")); return (PAM_SUCCESS); } PAM_EXTERN int pam_sm_chauthtok( pam_handle_t *pamh __attribute__((unused)), int flags __attribute__((unused)), int argc __attribute__((unused)), const char *argv[] __attribute__((unused))) { D(("pam_sm_chauthtok")); return (PAM_SERVICE_ERR); } #ifdef PAM_STATIC struct pam_module _pam_yubico_modstruct = { "pam_yubico", pam_sm_authenticate, pam_sm_setcred, pam_sm_acct_mgmt, pam_sm_open_session, pam_sm_close_session, pam_sm_chauthtok }; #endif