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samba-mirror/source3/libads/krb5_setpw.c
Jeremy Allison acf9d61421 r4088: Get medieval on our ass about malloc.... :-). Take control of all our allocation
functions so we can funnel through some well known functions. Should help greatly with
malloc checking.
HEAD patch to follow.
Jeremy.
(This used to be commit 620f2e608f70ba92f032720c031283d295c5c06a)
2007-10-10 10:53:32 -05:00

716 lines
20 KiB
C

/*
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 0xff80
#define KRB5_KPASSWD_VERS_SETPW_ALT 2
#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 = SMB_STRDUP(principal);
if ((c = strchr_m(princ, '/')) == NULL) {
c = princ;
} else {
*c = '\0';
c++;
princ_part1 = princ;
}
princ_part2 = c;
if ((c = strchr_m(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_ALT)
setpw = encode_krb5_setpw(princ, passwd);
else
return EINVAL;
encoded_setpw.data = (char *)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 *)SMB_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 const struct kpasswd_errors {
int result_code;
const char *error_string;
} kpasswd_errors[] = {
{KRB5_KPASSWD_MALFORMED, "Malformed request error"},
{KRB5_KPASSWD_HARDERROR, "Server error"},
{KRB5_KPASSWD_AUTHERROR, "Authentication error"},
{KRB5_KPASSWD_SOFTERROR, "Password change rejected"},
{KRB5_KPASSWD_ACCESSDENIED, "Client does not have proper authorization"},
{KRB5_KPASSWD_BAD_VERSION, "Protocol version not supported"},
{KRB5_KPASSWD_INITIAL_FLAG_NEEDED, "Authorization ticket must have initial flag set"},
{KRB5_KPASSWD_POLICY_REJECT, "Password rejected due to policy requirements"},
{KRB5_KPASSWD_BAD_PRINCIPAL, "Target principal does not exist"},
{KRB5_KPASSWD_ETYPE_NOSUPP, "Unsupported encryption type"},
{0, NULL}
};
static krb5_error_code setpw_result_code_string(krb5_context context,
int result_code,
const char **code_string)
{
unsigned int idx = 0;
while (kpasswd_errors[idx].error_string != NULL) {
if (kpasswd_errors[idx].result_code ==
result_code) {
*code_string = kpasswd_errors[idx].error_string;
return 0;
}
idx++;
}
*code_string = "Password change failed";
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_ALT &&
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;
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 *) SMB_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 ads_krb5_set_password(const char *kdc_host, const char *princ,
const char *newpw, int time_offset)
{
ADS_STATUS aret;
krb5_error_code ret = 0;
krb5_context context = NULL;
krb5_principal principal = NULL;
char *princ_name = NULL;
char *realm = NULL;
krb5_creds creds, *credsp = NULL;
#if KRB5_PRINC_REALM_RETURNS_REALM
krb5_realm orig_realm;
#else
krb5_data orig_realm;
#endif
krb5_ccache ccache = NULL;
ZERO_STRUCT(creds);
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);
}
realm = strchr_m(princ, '@');
if (!realm) {
krb5_cc_close(context, ccache);
krb5_free_context(context);
DEBUG(1,("Failed to get realm\n"));
return ADS_ERROR_KRB5(-1);
}
realm++;
asprintf(&princ_name, "kadmin/changepw@%s", realm);
ret = krb5_parse_name(context, princ_name, &creds.server);
if (ret) {
krb5_cc_close(context, ccache);
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_cc_close(context, ccache);
krb5_free_principal(context, creds.server);
krb5_free_context(context);
DEBUG(1,("Failed to parse %s (%s)\n", princ_name, error_message(ret)));
return ADS_ERROR_KRB5(ret);
}
/* The creds.server principal takes ownership of this memory.
Remember to set back to original value before freeing. */
orig_realm = *krb5_princ_realm(context, creds.server);
krb5_princ_set_realm(context, creds.server, krb5_princ_realm(context, principal));
ret = krb5_cc_get_principal(context, ccache, &creds.client);
if (ret) {
krb5_cc_close(context, ccache);
krb5_princ_set_realm(context, creds.server, &orig_realm);
krb5_free_principal(context, creds.server);
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_cc_close(context, ccache);
krb5_free_principal(context, creds.client);
krb5_princ_set_realm(context, creds.server, &orig_realm);
krb5_free_principal(context, creds.server);
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,
credsp, princ, newpw);
krb5_free_creds(context, credsp);
krb5_free_principal(context, creds.client);
krb5_princ_set_realm(context, creds.server, &orig_realm);
krb5_free_principal(context, creds.server);
krb5_free_principal(context, principal);
krb5_cc_close(context, ccache);
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 ads_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 = NULL;
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 = SMB_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, NULL, NULL))) {
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 ads_krb5_chg_password(kpasswd_server, target_principal,
auth_password, new_password, time_offset);
else
return ads_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 *machine_account,
const char *password)
{
ADS_STATUS status;
char *principal = NULL;
/*
we need to use the '$' form of the name here (the machine account name),
as otherwise the server might end up setting the password for a user
instead
*/
asprintf(&principal, "%s@%s", machine_account, ads->config.realm);
status = ads_krb5_set_password(ads->auth.kdc_server, principal,
password, ads->auth.time_offset);
free(principal);
return status;
}
#endif