diff options
Diffstat (limited to 'source4/libads/krb5_setpw.c')
| -rw-r--r-- | source4/libads/krb5_setpw.c | 701 |
1 files changed, 701 insertions, 0 deletions
diff --git a/source4/libads/krb5_setpw.c b/source4/libads/krb5_setpw.c new file mode 100644 index 0000000000..9d8fb8d24c --- /dev/null +++ b/source4/libads/krb5_setpw.c @@ -0,0 +1,701 @@ +/* + 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, + 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 { + 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, creds.server); + 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; +} + +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 |