/* Unix SMB/CIFS implementation. krb5 set password implementation Copyright (C) Andrew Tridgell 2001 Copyright (C) Remus Koos 2001 (remuskoos@yahoo.com) This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. 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; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" #ifdef HAVE_KRB5 #define DEFAULT_KPASSWD_PORT 464 #define KRB5_KPASSWD_VERS_CHANGEPW 1 #define KRB5_KPASSWD_VERS_SETPW 2 #define KRB5_KPASSWD_VERS_SETPW_MS 0xff80 #define KRB5_KPASSWD_ACCESSDENIED 5 #define KRB5_KPASSWD_BAD_VERSION 6 #define KRB5_KPASSWD_INITIAL_FLAG_NEEDED 7 /* Those are defined by kerberos-set-passwd-02.txt and are probably * not supported by M$ implementation */ #define KRB5_KPASSWD_POLICY_REJECT 8 #define KRB5_KPASSWD_BAD_PRINCIPAL 9 #define KRB5_KPASSWD_ETYPE_NOSUPP 10 /* This implements kerberos password change protocol as specified in * kerb-chg-password-02.txt and kerberos-set-passwd-02.txt * as well as microsoft version of the protocol * as specified in kerberos-set-passwd-00.txt */ static DATA_BLOB encode_krb5_setpw(const char *principal, const char *password) { char* princ_part1 = NULL; char* princ_part2 = NULL; char* realm = NULL; char* c; char* princ; ASN1_DATA req; DATA_BLOB ret; princ = strdup(principal); if ((c = strchr(princ, '/')) == NULL) { c = princ; } else { *c = '\0'; c++; princ_part1 = princ; } princ_part2 = c; if ((c = strchr(c, '@')) != NULL) { *c = '\0'; c++; realm = c; } memset(&req, 0, sizeof(req)); asn1_push_tag(&req, ASN1_SEQUENCE(0)); asn1_push_tag(&req, ASN1_CONTEXT(0)); asn1_write_OctetString(&req, password, strlen(password)); asn1_pop_tag(&req); asn1_push_tag(&req, ASN1_CONTEXT(1)); asn1_push_tag(&req, ASN1_SEQUENCE(0)); asn1_push_tag(&req, ASN1_CONTEXT(0)); asn1_write_Integer(&req, 1); asn1_pop_tag(&req); asn1_push_tag(&req, ASN1_CONTEXT(1)); asn1_push_tag(&req, ASN1_SEQUENCE(0)); if (princ_part1) asn1_write_GeneralString(&req, princ_part1); asn1_write_GeneralString(&req, princ_part2); asn1_pop_tag(&req); asn1_pop_tag(&req); asn1_pop_tag(&req); asn1_pop_tag(&req); asn1_push_tag(&req, ASN1_CONTEXT(2)); asn1_write_GeneralString(&req, realm); asn1_pop_tag(&req); asn1_pop_tag(&req); ret = data_blob(req.data, req.length); asn1_free(&req); free(princ); return ret; } static krb5_error_code build_kpasswd_request(uint16 pversion, krb5_context context, krb5_auth_context auth_context, krb5_data *ap_req, const char *princ, const char *passwd, krb5_data *packet) { krb5_error_code ret; krb5_data cipherpw; krb5_data encoded_setpw; krb5_replay_data replay; char *p; DATA_BLOB setpw; ret = krb5_auth_con_setflags(context, auth_context,KRB5_AUTH_CONTEXT_DO_SEQUENCE); if (ret) { DEBUG(1,("krb5_auth_con_setflags failed (%s)\n", error_message(ret))); return ret; } /* handle protocol differences in chpw and setpw */ if (pversion == KRB5_KPASSWD_VERS_CHANGEPW) setpw = data_blob(passwd, strlen(passwd)); else if (pversion == KRB5_KPASSWD_VERS_SETPW || pversion == KRB5_KPASSWD_VERS_SETPW_MS) setpw = encode_krb5_setpw(princ, passwd); else return EINVAL; encoded_setpw.data = setpw.data; encoded_setpw.length = setpw.length; ret = krb5_mk_priv(context, auth_context, &encoded_setpw, &cipherpw, &replay); data_blob_free(&setpw); /*from 'encode_krb5_setpw(...)' */ if (ret) { DEBUG(1,("krb5_mk_priv failed (%s)\n", error_message(ret))); return ret; } packet->data = (char *)malloc(ap_req->length + cipherpw.length + 6); if (!packet->data) return -1; /* see the RFC for details */ p = ((char *)packet->data) + 2; RSSVAL(p, 0, pversion); p += 2; RSSVAL(p, 0, ap_req->length); p += 2; memcpy(p, ap_req->data, ap_req->length); p += ap_req->length; memcpy(p, cipherpw.data, cipherpw.length); p += cipherpw.length; packet->length = PTR_DIFF(p,packet->data); RSSVAL(packet->data, 0, packet->length); free(cipherpw.data); /* from 'krb5_mk_priv(...)' */ return 0; } static krb5_error_code krb5_setpw_result_code_string(krb5_context context, int result_code, const char **code_string) { switch (result_code) { case KRB5_KPASSWD_MALFORMED: *code_string = "Malformed request error"; break; case KRB5_KPASSWD_HARDERROR: *code_string = "Server error"; break; case KRB5_KPASSWD_AUTHERROR: *code_string = "Authentication error"; break; case KRB5_KPASSWD_SOFTERROR: *code_string = "Password change rejected"; break; case KRB5_KPASSWD_ACCESSDENIED: *code_string = "Client does not have proper authorization"; break; case KRB5_KPASSWD_BAD_VERSION: *code_string = "Protocol version not supported"; break; case KRB5_KPASSWD_INITIAL_FLAG_NEEDED: *code_string = "Authorization ticket must have initial flag set"; break; case KRB5_KPASSWD_POLICY_REJECT: *code_string = "Password rejected due to policy requirements"; break; case KRB5_KPASSWD_BAD_PRINCIPAL: *code_string = "Target principal does not exist"; break; case KRB5_KPASSWD_ETYPE_NOSUPP: *code_string = "Unsupported encryption type"; break; default: *code_string = "Password change failed"; break; } return(0); } static krb5_error_code parse_setpw_reply(krb5_context context, krb5_auth_context auth_context, krb5_data *packet) { krb5_data ap_rep; char *p; int vnum, ret, res_code; krb5_data cipherresult; krb5_data clearresult; krb5_ap_rep_enc_part *ap_rep_enc; krb5_replay_data replay; if (packet->length < 4) { return KRB5KRB_AP_ERR_MODIFIED; } p = packet->data; if (((char *)packet->data)[0] == 0x7e || ((char *)packet->data)[0] == 0x5e) { /* it's an error packet. We should parse it ... */ DEBUG(1,("Got error packet 0x%x from kpasswd server\n", ((char *)packet->data)[0])); return KRB5KRB_AP_ERR_MODIFIED; } if (RSVAL(p, 0) != packet->length) { DEBUG(1,("Bad packet length (%d/%d) from kpasswd server\n", RSVAL(p, 0), packet->length)); return KRB5KRB_AP_ERR_MODIFIED; } p += 2; vnum = RSVAL(p, 0); p += 2; /* FIXME: According to standard there is only one type of reply */ if (vnum != KRB5_KPASSWD_VERS_SETPW && vnum != KRB5_KPASSWD_VERS_SETPW_MS && vnum != KRB5_KPASSWD_VERS_CHANGEPW) { DEBUG(1,("Bad vnum (%d) from kpasswd server\n", vnum)); return KRB5KDC_ERR_BAD_PVNO; } ap_rep.length = RSVAL(p, 0); p += 2; if (p + ap_rep.length >= (char *)packet->data + packet->length) { DEBUG(1,("ptr beyond end of packet from kpasswd server\n")); return KRB5KRB_AP_ERR_MODIFIED; } if (ap_rep.length == 0) { DEBUG(1,("got unencrypted setpw result?!\n")); return KRB5KRB_AP_ERR_MODIFIED; } /* verify ap_rep */ ap_rep.data = p; p += ap_rep.length; ret = krb5_rd_rep(context, auth_context, &ap_rep, &ap_rep_enc); if (ret) { DEBUG(1,("failed to rd setpw reply (%s)\n", error_message(ret))); return KRB5KRB_AP_ERR_MODIFIED; } krb5_free_ap_rep_enc_part(context, ap_rep_enc); cipherresult.data = p; cipherresult.length = ((char *)packet->data + packet->length) - p; ret = krb5_rd_priv(context, auth_context, &cipherresult, &clearresult, &replay); if (ret) { DEBUG(1,("failed to decrypt setpw reply (%s)\n", error_message(ret))); return KRB5KRB_AP_ERR_MODIFIED; } if (clearresult.length < 2) { free(clearresult.data); ret = KRB5KRB_AP_ERR_MODIFIED; return KRB5KRB_AP_ERR_MODIFIED; } p = clearresult.data; res_code = RSVAL(p, 0); free(clearresult.data); if ((res_code < KRB5_KPASSWD_SUCCESS) || (res_code > KRB5_KPASSWD_ETYPE_NOSUPP)) { return KRB5KRB_AP_ERR_MODIFIED; } if(res_code == KRB5_KPASSWD_SUCCESS) return 0; else { const char *errstr; krb5_setpw_result_code_string(context, res_code, &errstr); DEBUG(1, ("Error changing password: %s\n", errstr)); switch(res_code) { case KRB5_KPASSWD_ACCESSDENIED: return KRB5KDC_ERR_BADOPTION; break; case KRB5_KPASSWD_INITIAL_FLAG_NEEDED: return KRB5KDC_ERR_BADOPTION; /* return KV5M_ALT_METHOD; MIT-only define */ break; case KRB5_KPASSWD_ETYPE_NOSUPP: return KRB5KDC_ERR_ETYPE_NOSUPP; break; case KRB5_KPASSWD_BAD_PRINCIPAL: return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN; break; case KRB5_KPASSWD_POLICY_REJECT: return KRB5KDC_ERR_POLICY; break; default: return KRB5KRB_ERR_GENERIC; break; } } } static ADS_STATUS do_krb5_kpasswd_request(krb5_context context, const char *kdc_host, uint16 pversion, krb5_creds *credsp, const char *princ, const char *newpw) { krb5_auth_context auth_context = NULL; krb5_data ap_req, chpw_req, chpw_rep; int ret, sock, addr_len; struct sockaddr remote_addr, local_addr; krb5_address local_kaddr, remote_kaddr; ret = krb5_mk_req_extended(context, &auth_context, AP_OPTS_USE_SUBKEY, NULL, credsp, &ap_req); if (ret) { DEBUG(1,("krb5_mk_req_extended failed (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } sock = open_udp_socket(kdc_host, DEFAULT_KPASSWD_PORT); if (sock == -1) { int rc = errno; free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("failed to open kpasswd socket to %s (%s)\n", kdc_host, strerror(errno))); return ADS_ERROR_SYSTEM(rc); } addr_len = sizeof(remote_addr); getpeername(sock, &remote_addr, &addr_len); addr_len = sizeof(local_addr); getsockname(sock, &local_addr, &addr_len); setup_kaddr(&remote_kaddr, &remote_addr); setup_kaddr(&local_kaddr, &local_addr); ret = krb5_auth_con_setaddrs(context, auth_context, &local_kaddr, NULL); if (ret) { close(sock); free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("krb5_auth_con_setaddrs failed (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } ret = build_kpasswd_request(pversion, context, auth_context, &ap_req, princ, newpw, &chpw_req); if (ret) { close(sock); free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("build_setpw_request failed (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } if (write(sock, chpw_req.data, chpw_req.length) != chpw_req.length) { close(sock); free(chpw_req.data); free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("send of chpw failed (%s)\n", strerror(errno))); return ADS_ERROR_SYSTEM(errno); } free(chpw_req.data); chpw_rep.length = 1500; chpw_rep.data = (char *) malloc(chpw_rep.length); if (!chpw_rep.data) { close(sock); free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("send of chpw failed (%s)\n", strerror(errno))); errno = ENOMEM; return ADS_ERROR_SYSTEM(errno); } ret = read(sock, chpw_rep.data, chpw_rep.length); if (ret < 0) { close(sock); free(chpw_rep.data); free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("recv of chpw reply failed (%s)\n", strerror(errno))); return ADS_ERROR_SYSTEM(errno); } close(sock); chpw_rep.length = ret; ret = krb5_auth_con_setaddrs(context, auth_context, NULL,&remote_kaddr); if (ret) { free(chpw_rep.data); free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("krb5_auth_con_setaddrs on reply failed (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } ret = parse_setpw_reply(context, auth_context, &chpw_rep); free(chpw_rep.data); if (ret) { free(ap_req.data); krb5_auth_con_free(context, auth_context); DEBUG(1,("parse_setpw_reply failed (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } free(ap_req.data); krb5_auth_con_free(context, auth_context); return ADS_SUCCESS; } ADS_STATUS krb5_set_password(const char *kdc_host, const char *princ, const char *newpw, int time_offset) { ADS_STATUS aret; krb5_error_code ret; krb5_context context; krb5_principal principal; char *princ_name; char *realm; krb5_creds creds, *credsp; krb5_ccache ccache; ret = krb5_init_context(&context); if (ret) { DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } if (time_offset != 0) { krb5_set_real_time(context, time(NULL) + time_offset, 0); } ret = krb5_cc_default(context, &ccache); if (ret) { krb5_free_context(context); DEBUG(1,("Failed to get default creds (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } ZERO_STRUCT(creds); realm = strchr(princ, '@'); realm++; asprintf(&princ_name, "kadmin/changepw@%s", realm); ret = krb5_parse_name(context, princ_name, &creds.server); if (ret) { krb5_free_context(context); DEBUG(1,("Failed to parse kadmin/changepw (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } free(princ_name); /* parse the principal we got as a function argument */ ret = krb5_parse_name(context, princ, &principal); if (ret) { krb5_free_context(context); DEBUG(1,("Failed to parse %s (%s)\n", princ_name, error_message(ret))); return ADS_ERROR_KRB5(ret); } krb5_princ_set_realm(context, creds.server, krb5_princ_realm(context, principal)); ret = krb5_cc_get_principal(context, ccache, &creds.client); if (ret) { krb5_free_principal(context, principal); krb5_free_context(context); DEBUG(1,("Failed to get principal from ccache (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } ret = krb5_get_credentials(context, 0, ccache, &creds, &credsp); if (ret) { krb5_free_principal(context, creds.client); krb5_free_principal(context, principal); krb5_free_context(context); DEBUG(1,("krb5_get_credentials failed (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } /* we might have to call krb5_free_creds(...) from now on ... */ aret = do_krb5_kpasswd_request(context, kdc_host, KRB5_KPASSWD_VERS_SETPW_MS, credsp, princ, newpw); krb5_free_creds(context, credsp); krb5_free_principal(context, creds.client); krb5_free_principal(context, principal); krb5_free_context(context); return aret; } /* we use a prompter to avoid a crash bug in the kerberos libs when dealing with empty passwords this prompter is just a string copy ... */ static krb5_error_code kerb_prompter(krb5_context ctx, void *data, const char *name, const char *banner, int num_prompts, krb5_prompt prompts[]) { if (num_prompts == 0) return 0; memset(prompts[0].reply->data, 0, prompts[0].reply->length); if (prompts[0].reply->length > 0) { if (data) { strncpy(prompts[0].reply->data, data, prompts[0].reply->length-1); prompts[0].reply->length = strlen(prompts[0].reply->data); } else { prompts[0].reply->length = 0; } } return 0; } static ADS_STATUS krb5_chg_password(const char *kdc_host, const char *principal, const char *oldpw, const char *newpw, int time_offset) { ADS_STATUS aret; krb5_error_code ret; krb5_context context; krb5_principal princ; krb5_get_init_creds_opt opts; krb5_creds creds; char *chpw_princ = NULL, *password; ret = krb5_init_context(&context); if (ret) { DEBUG(1,("Failed to init krb5 context (%s)\n", error_message(ret))); return ADS_ERROR_KRB5(ret); } if ((ret = krb5_parse_name(context, principal, &princ))) { krb5_free_context(context); DEBUG(1,("Failed to parse %s (%s)\n", principal, error_message(ret))); return ADS_ERROR_KRB5(ret); } krb5_get_init_creds_opt_init(&opts); krb5_get_init_creds_opt_set_tkt_life(&opts, 5*60); krb5_get_init_creds_opt_set_renew_life(&opts, 0); krb5_get_init_creds_opt_set_forwardable(&opts, 0); krb5_get_init_creds_opt_set_proxiable(&opts, 0); /* We have to obtain an INITIAL changepw ticket for changing password */ asprintf(&chpw_princ, "kadmin/changepw@%s", (char *) krb5_princ_realm(context, princ)); password = strdup(oldpw); ret = krb5_get_init_creds_password(context, &creds, princ, password, kerb_prompter, NULL, 0, chpw_princ, &opts); SAFE_FREE(chpw_princ); SAFE_FREE(password); if (ret) { if (ret == KRB5KRB_AP_ERR_BAD_INTEGRITY) DEBUG(1,("Password incorrect while getting initial ticket")); else DEBUG(1,("krb5_get_init_creds_password failed (%s)\n", error_message(ret))); krb5_free_principal(context, princ); krb5_free_context(context); return ADS_ERROR_KRB5(ret); } aret = do_krb5_kpasswd_request(context, kdc_host, KRB5_KPASSWD_VERS_CHANGEPW, &creds, principal, newpw); krb5_free_principal(context, princ); krb5_free_context(context); return aret; } ADS_STATUS kerberos_set_password(const char *kpasswd_server, const char *auth_principal, const char *auth_password, const char *target_principal, const char *new_password, int time_offset) { int ret; if ((ret = kerberos_kinit_password(auth_principal, auth_password, time_offset))) { DEBUG(1,("Failed kinit for principal %s (%s)\n", auth_principal, error_message(ret))); return ADS_ERROR_KRB5(ret); } if (!strcmp(auth_principal, target_principal)) return krb5_chg_password(kpasswd_server, target_principal, auth_password, new_password, time_offset); else return krb5_set_password(kpasswd_server, target_principal, new_password, time_offset); } /** * Set the machine account password * @param ads connection to ads server * @param hostname machine whose password is being set * @param password new password * @return status of password change **/ ADS_STATUS ads_set_machine_password(ADS_STRUCT *ads, const char *hostname, const char *password) { ADS_STATUS status; char *host = strdup(hostname); char *principal; strlower(host); /* we need to use the '$' form of the name here, as otherwise the server might end up setting the password for a user instead */ asprintf(&principal, "%s$@%s", host, ads->auth.realm); status = krb5_set_password(ads->auth.kdc_server, principal, password, ads->auth.time_offset); free(host); free(principal); return status; } #endif