krb5_auth.c revision 777f5bc1fb5f2ba4267de83843beee51090eb8d5
/*
SSSD
Kerberos 5 Backend Module
Authors:
Sumit Bose <sbose@redhat.com>
Copyright (C) 2009-2010 Red Hat
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <pwd.h>
#include <sys/stat.h>
#include <security/pam_modules.h>
#include "util/util.h"
#include "util/find_uid.h"
#include "util/auth_utils.h"
#include "db/sysdb.h"
#include "util/child_common.h"
#include "providers/krb5/krb5_auth.h"
#include "providers/krb5/krb5_utils.h"
static errno_t safe_remove_old_ccache_file(struct sss_krb5_cc_be *cc_be,
const char *princ,
const char *old_ccache,
const char *new_ccache)
{
int ret;
enum sss_krb5_cc_type old_type;
struct sss_krb5_cc_be *old_cc_ops;
if (old_ccache == NULL) {
DEBUG(SSSDBG_FUNC_DATA, ("No old ccache, nothing to do\n"));
return EOK;
}
if (new_ccache == NULL) {
DEBUG(SSSDBG_OP_FAILURE,
("Missing new ccache file, old ccache file is not deleted.\n"));
return EINVAL;
}
old_type = sss_krb5_get_type(old_ccache);
old_cc_ops = get_cc_be_ops(old_type);
if (!old_cc_ops) {
DEBUG(SSSDBG_CRIT_FAILURE, ("Cannot get ccache operations\n"));
return EINVAL;
}
if (cc_be->type == old_type &&
strcmp(old_ccache, new_ccache) == 0) {
DEBUG(SSSDBG_TRACE_FUNC, ("New and old ccache file are the same, "
"no one will be deleted.\n"));
return EOK;
}
ret = old_cc_ops->remove(old_ccache);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE,
("Cannot remove ccache [%s]\n", old_ccache));
return EIO;
}
return EOK;
}
static errno_t
check_old_ccache(const char *old_ccache, struct krb5child_req *kr,
const char *realm, bool *active, bool *valid)
{
struct sss_krb5_cc_be *old_cc_ops;
const char *cc_template;
errno_t ret;
/* ccache file might be of a different type if the user changed
* configuration
*/
old_cc_ops = get_cc_be_ops_ccache(old_ccache);
if (old_cc_ops == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE,
("Cannot get operations on saved ccache %s\n", old_ccache));
return EINVAL;
}
cc_template = dp_opt_get_cstring(kr->krb5_ctx->opts, KRB5_CCNAME_TMPL);
ret = old_cc_ops->check_existing(old_ccache, kr->uid, realm, kr->upn,
cc_template, active, valid);
if (ret != EOK) {
DEBUG(SSSDBG_OP_FAILURE,
("Cannot check if saved ccache %s is active and valid\n",
old_ccache));
return ret;
}
return EOK;
}
static int krb5_mod_ccname(TALLOC_CTX *mem_ctx,
struct sysdb_ctx *sysdb,
struct sss_domain_info *domain,
const char *name,
const char *ccname,
int mod_op)
{
TALLOC_CTX *tmpctx;
struct sysdb_attrs *attrs;
int ret;
errno_t sret;
bool in_transaction = false;
if (name == NULL || ccname == NULL) {
DEBUG(1, ("Missing user or ccache name.\n"));
return EINVAL;
}
if (mod_op != SYSDB_MOD_REP && mod_op != SYSDB_MOD_DEL) {
DEBUG(1, ("Unsupported operation [%d].\n", mod_op));
return EINVAL;
}
DEBUG(9, ("%s ccname [%s] for user [%s].\n",
mod_op == SYSDB_MOD_REP ? "Save" : "Delete", ccname, name));
tmpctx = talloc_new(mem_ctx);
if (!tmpctx) {
return ENOMEM;
}
attrs = sysdb_new_attrs(tmpctx);
if (!attrs) {
ret = ENOMEM;
goto done;
}
ret = sysdb_attrs_add_string(attrs, SYSDB_CCACHE_FILE, ccname);
if (ret != EOK) {
DEBUG(1, ("sysdb_attrs_add_string failed.\n"));
goto done;
}
ret = sysdb_transaction_start(sysdb);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE,
("Error %d starting transaction (%s)\n", ret, strerror(ret)));
goto done;
}
in_transaction = true;
ret = sysdb_set_user_attr(sysdb, domain, name, attrs, mod_op);
if (ret != EOK) {
DEBUG(6, ("Error: %d (%s)\n", ret, strerror(ret)));
goto done;
}
ret = sysdb_transaction_commit(sysdb);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE, ("Failed to commit transaction!\n"));
goto done;
}
in_transaction = false;
done:
if (in_transaction) {
sret = sysdb_transaction_cancel(sysdb);
if (sret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE, ("Failed to cancel transaction\n"));
}
}
talloc_zfree(tmpctx);
return ret;
}
static int krb5_save_ccname(TALLOC_CTX *mem_ctx,
struct sysdb_ctx *sysdb,
struct sss_domain_info *domain,
const char *name,
const char *ccname)
{
return krb5_mod_ccname(mem_ctx, sysdb, domain, name, ccname,
SYSDB_MOD_REP);
}
static int krb5_delete_ccname(TALLOC_CTX *mem_ctx,
struct sysdb_ctx *sysdb,
struct sss_domain_info *domain,
const char *name,
const char *ccname)
{
return krb5_mod_ccname(mem_ctx, sysdb, domain, name, ccname,
SYSDB_MOD_DEL);
}
static struct krb5_ctx *get_krb5_ctx(struct be_req *be_req)
{
struct pam_data *pd;
pd = talloc_get_type(be_req->req_data, struct pam_data);
switch (pd->cmd) {
case SSS_PAM_AUTHENTICATE:
case SSS_CMD_RENEW:
return talloc_get_type(be_req->be_ctx->bet_info[BET_AUTH].pvt_bet_data,
struct krb5_ctx);
break;
case SSS_PAM_ACCT_MGMT:
return talloc_get_type(be_req->be_ctx->bet_info[BET_ACCESS].pvt_bet_data,
struct krb5_ctx);
break;
case SSS_PAM_CHAUTHTOK:
case SSS_PAM_CHAUTHTOK_PRELIM:
return talloc_get_type(be_req->be_ctx->bet_info[BET_CHPASS].pvt_bet_data,
struct krb5_ctx);
break;
default:
DEBUG(1, ("Unsupported PAM task.\n"));
return NULL;
}
}
static void krb_reply(struct be_req *req, int dp_err, int result);
static int krb5_cleanup(void *ptr)
{
struct krb5child_req *kr = talloc_get_type(ptr, struct krb5child_req);
if (kr == NULL) return EOK;
memset(kr, 0, sizeof(struct krb5child_req));
return EOK;
}
errno_t krb5_setup(TALLOC_CTX *mem_ctx, struct pam_data *pd,
struct krb5_ctx *krb5_ctx, struct krb5child_req **krb5_req)
{
struct krb5child_req *kr = NULL;
kr = talloc_zero(mem_ctx, struct krb5child_req);
if (kr == NULL) {
DEBUG(1, ("talloc failed.\n"));
return ENOMEM;
}
kr->is_offline = false;
kr->active_ccache = true;
kr->run_as_user = true;
talloc_set_destructor((TALLOC_CTX *) kr, krb5_cleanup);
kr->pd = pd;
kr->krb5_ctx = krb5_ctx;
*krb5_req = kr;
return EOK;
}
static void krb5_auth_cache_creds(struct krb5_ctx *krb5_ctx,
struct sysdb_ctx *sysdb,
struct confdb_ctx *cdb,
struct pam_data *pd, uid_t uid,
int *pam_status, int *dp_err)
{
const char *password = NULL;
errno_t ret;
ret = sss_authtok_get_password(&pd->authtok, &password, NULL);
if (ret != EOK) {
DEBUG(0, ("Failed to get password [%d] %s\n", ret, strerror(ret)));
*pam_status = PAM_SYSTEM_ERR;
*dp_err = DP_ERR_OK;
return;
}
ret = sysdb_cache_auth(sysdb, pd->user, password, cdb, true, NULL, NULL);
if (ret != EOK) {
DEBUG(1, ("Offline authentication failed\n"));
*pam_status = cached_login_pam_status(ret);
*dp_err = DP_ERR_OK;
return;
}
ret = add_user_to_delayed_online_authentication(krb5_ctx, pd, uid);
if (ret != EOK) {
/* This error is not fatal */
DEBUG(1, ("add_user_to_delayed_online_authentication failed.\n"));
}
*pam_status = PAM_AUTHINFO_UNAVAIL;
*dp_err = DP_ERR_OFFLINE;
}
static errno_t krb5_auth_prepare_ccache_file(struct krb5child_req *kr,
struct be_ctx *be_ctx,
int *pam_status, int *dp_err)
{
const char *ccname_template;
bool private_path = false;
errno_t ret;
if (!kr->is_offline) {
kr->is_offline = be_is_offline(be_ctx);
}
/* The ccache file should be (re)created if one of the following conditions
* is true:
* - it doesn't exist (kr->ccname == NULL)
* - the backend is online and the current ccache file is not used, i.e
* the related user is currently not logged in and it is not a renewal
* request
* (!kr->is_offline && !kr->active_ccache && kr->pd->cmd != SSS_CMD_RENEW)
* - the backend is offline and the current cache file not used and
* it does not contain a valid tgt
* (kr->is_offline && !kr->active_ccache && !kr->valid_tgt)
*/
if (kr->ccname == NULL ||
(kr->is_offline && !kr->active_ccache && !kr->valid_tgt) ||
(!kr->is_offline && !kr->active_ccache && kr->pd->cmd != SSS_CMD_RENEW)) {
DEBUG(9, ("Recreating ccache file.\n"));
ccname_template = dp_opt_get_cstring(kr->krb5_ctx->opts,
KRB5_CCNAME_TMPL);
kr->ccname = expand_ccname_template(kr, kr, ccname_template, true,
be_ctx->domain->case_sensitive,
&private_path);
if (kr->ccname == NULL) {
DEBUG(1, ("expand_ccname_template failed.\n"));
return ENOMEM;
}
if (kr->cc_be == NULL) {
kr->cc_be = get_cc_be_ops_ccache(kr->ccname);
}
if (kr->cc_be == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE,
("Cannot get operations on new ccache %s\n", kr->ccname));
return EINVAL;
}
ret = kr->cc_be->create(kr->ccname,
kr->krb5_ctx->illegal_path_re,
kr->uid, kr->gid, private_path);
if (ret != EOK) {
DEBUG(SSSDBG_OP_FAILURE, ("ccache creation failed.\n"));
return ret;
}
} else {
DEBUG(SSSDBG_MINOR_FAILURE,
("Saved ccache %s if of different type than ccache in "
"configuration file, reusing the old ccache\n",
kr->old_ccname));
kr->cc_be = get_cc_be_ops_ccache(kr->old_ccname);
if (kr->cc_be == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE,
("Cannot get operations on saved ccache %s\n",
kr->old_ccname));
return EINVAL;
}
}
return EOK;
}
static void krb5_auth_store_creds(struct sysdb_ctx *sysdb,
struct sss_domain_info *domain,
struct pam_data *pd)
{
const char *password = NULL;
int ret = EOK;
switch(pd->cmd) {
case SSS_CMD_RENEW:
/* The authtok is set to the credential cache
* during renewal. We don't want to save this
* as the cached password.
*/
break;
case SSS_PAM_AUTHENTICATE:
case SSS_PAM_CHAUTHTOK_PRELIM:
ret = sss_authtok_get_password(&pd->authtok, &password, NULL);
break;
case SSS_PAM_CHAUTHTOK:
ret = sss_authtok_get_password(&pd->newauthtok, &password, NULL);
break;
default:
DEBUG(0, ("unsupported PAM command [%d].\n", pd->cmd));
}
if (ret != EOK) {
DEBUG(0, ("Failed to get password [%d] %s\n", ret, strerror(ret)));
/* password caching failures are not fatal errors */
return;
}
if (password == NULL) {
if (pd->cmd != SSS_CMD_RENEW) {
DEBUG(0, ("password not available, offline auth may not work.\n"));
/* password caching failures are not fatal errors */
}
return;
}
ret = sysdb_cache_password(sysdb, domain, pd->user, password);
if (ret) {
DEBUG(2, ("Failed to cache password, offline auth may not work."
" (%d)[%s]!?\n", ret, strerror(ret)));
/* password caching failures are not fatal errors */
}
}
/* krb5_auth request */
struct krb5_auth_state {
struct tevent_context *ev;
struct be_ctx *be_ctx;
struct pam_data *pd;
struct sysdb_ctx *sysdb;
struct sss_domain_info *domain;
struct krb5_ctx *krb5_ctx;
struct krb5child_req *kr;
bool search_kpasswd;
int pam_status;
int dp_err;
};
static void krb5_auth_resolve_done(struct tevent_req *subreq);
static void krb5_auth_done(struct tevent_req *subreq);
struct tevent_req *krb5_auth_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct be_ctx *be_ctx,
struct pam_data *pd,
struct krb5_ctx *krb5_ctx)
{
const char **attrs;
struct krb5_auth_state *state;
struct ldb_result *res;
struct krb5child_req *kr = NULL;
const char *ccache_file = NULL;
const char *realm;
struct tevent_req *req;
struct tevent_req *subreq;
int ret;
req = tevent_req_create(mem_ctx, &state, struct krb5_auth_state);
if (req == NULL) {
DEBUG(1, ("tevent_req_create failed.\n"));
return NULL;
}
state->ev = ev;
state->be_ctx = be_ctx;
state->pd = pd;
state->krb5_ctx = krb5_ctx;
state->kr = NULL;
state->pam_status = PAM_SYSTEM_ERR;
state->dp_err = DP_ERR_FATAL;
ret = get_domain_or_subdomain(state, be_ctx, pd->domain, &state->domain);
if (ret != EOK) {
DEBUG(SSSDBG_OP_FAILURE, ("get_domain_or_subdomain failed.\n"));
goto done;
}
state->sysdb = state->domain->sysdb;
switch (pd->cmd) {
case SSS_PAM_AUTHENTICATE:
case SSS_CMD_RENEW:
case SSS_PAM_CHAUTHTOK:
if (sss_authtok_get_type(&pd->authtok) != SSS_AUTHTOK_TYPE_PASSWORD) {
DEBUG(1, ("Missing authtok for user [%s].\n", pd->user));
state->pam_status = PAM_SYSTEM_ERR;
state->dp_err = DP_ERR_FATAL;
ret = EINVAL;
goto done;
}
break;
case SSS_PAM_CHAUTHTOK_PRELIM:
if (pd->priv == 1 &&
sss_authtok_get_type(&pd->authtok) != SSS_AUTHTOK_TYPE_PASSWORD) {
DEBUG(4, ("Password reset by root is not supported.\n"));
state->pam_status = PAM_PERM_DENIED;
state->dp_err = DP_ERR_OK;
ret = EOK;
goto done;
}
break;
default:
DEBUG(4, ("Unexpected pam task %d.\n", pd->cmd));
state->pam_status = PAM_SYSTEM_ERR;
state->dp_err = DP_ERR_FATAL;
ret = EINVAL;
goto done;
}
if (be_is_offline(be_ctx) &&
(pd->cmd == SSS_PAM_CHAUTHTOK || pd->cmd == SSS_PAM_CHAUTHTOK_PRELIM ||
pd->cmd == SSS_CMD_RENEW)) {
DEBUG(9, ("Password changes and ticket renewal are not possible "
"while offline.\n"));
state->pam_status = PAM_AUTHINFO_UNAVAIL;
state->dp_err = DP_ERR_OFFLINE;
ret = EOK;
goto done;
}
attrs = talloc_array(state, const char *, 6);
if (attrs == NULL) {
ret = ENOMEM;
goto done;
}
attrs[0] = SYSDB_UPN;
attrs[1] = SYSDB_HOMEDIR;
attrs[2] = SYSDB_CCACHE_FILE;
attrs[3] = SYSDB_UIDNUM;
attrs[4] = SYSDB_GIDNUM;
attrs[5] = NULL;
ret = krb5_setup(state, pd, krb5_ctx, &state->kr);
if (ret != EOK) {
DEBUG(1, ("krb5_setup failed.\n"));
goto done;
}
kr = state->kr;
ret = sysdb_get_user_attr(state, state->sysdb, state->domain,
state->pd->user, attrs, &res);
if (ret) {
DEBUG(5, ("sysdb search for upn of user [%s] failed.\n", pd->user));
state->pam_status = PAM_SYSTEM_ERR;
state->dp_err = DP_ERR_OK;
goto done;
}
realm = dp_opt_get_cstring(krb5_ctx->opts, KRB5_REALM);
if (realm == NULL) {
DEBUG(1, ("Missing Kerberos realm.\n"));
ret = ENOENT;
goto done;
}
switch (res->count) {
case 0:
DEBUG(5, ("No attributes for user [%s] found.\n", pd->user));
ret = ENOENT;
goto done;
break;
case 1:
ret = find_or_guess_upn(state, res->msgs[0], krb5_ctx,
be_ctx->domain->name, pd->user, pd->domain,
&kr->upn);
if (ret != EOK) {
DEBUG(SSSDBG_OP_FAILURE, ("find_or_guess_upn failed.\n"));
goto done;
}
ret = compare_principal_realm(kr->upn, realm,
&kr->upn_from_different_realm);
if (ret != 0) {
DEBUG(SSSDBG_OP_FAILURE, ("compare_principal_realm failed.\n"));
goto done;
}
kr->homedir = ldb_msg_find_attr_as_string(res->msgs[0], SYSDB_HOMEDIR,
NULL);
if (kr->homedir == NULL) {
DEBUG(4, ("Home directory for user [%s] not known.\n", pd->user));
}
kr->uid = ldb_msg_find_attr_as_uint64(res->msgs[0], SYSDB_UIDNUM, 0);
if (kr->uid == 0) {
DEBUG(4, ("UID for user [%s] not known.\n", pd->user));
ret = ENOENT;
goto done;
}
kr->gid = ldb_msg_find_attr_as_uint64(res->msgs[0], SYSDB_GIDNUM, 0);
if (kr->gid == 0) {
DEBUG(4, ("GID for user [%s] not known.\n", pd->user));
ret = ENOENT;
goto done;
}
/* The type of the ccache might change during the request if we
* end up reusing an old ccache */
kr->cc_be = krb5_ctx->cc_be;
ccache_file = ldb_msg_find_attr_as_string(res->msgs[0],
SYSDB_CCACHE_FILE,
NULL);
if (ccache_file != NULL) {
ret = check_old_ccache(ccache_file, kr, realm,
&kr->active_ccache,
&kr->valid_tgt);
if (ret != EOK) {
DEBUG(SSSDBG_CRIT_FAILURE,
("check_if_ccache_file_is_used failed.\n"));
goto done;
}
} else {
kr->active_ccache = false;
kr->valid_tgt = false;
DEBUG(4, ("No ccache file for user [%s] found.\n", pd->user));
}
DEBUG(9, ("Ccache_file is [%s] and is %s active and TGT is %s valid.\n",
ccache_file ? ccache_file : "not set",
kr->active_ccache ? "" : "not",
kr->valid_tgt ? "" : "not"));
if (ccache_file != NULL) {
kr->ccname = ccache_file;
kr->old_ccname = talloc_strdup(kr, ccache_file);
if (kr->old_ccname == NULL) {
DEBUG(1, ("talloc_strdup failed.\n"));
ret = ENOMEM;
goto done;
}
} else {
kr->ccname = NULL;
kr->old_ccname = NULL;
}
break;
default:
DEBUG(1, ("User search for (%s) returned > 1 results!\n", pd->user));
ret = EINVAL;
goto done;
break;
}
kr->srv = NULL;
kr->kpasswd_srv = NULL;
state->search_kpasswd = false;
subreq = be_resolve_server_send(state, state->ev, state->be_ctx,
state->krb5_ctx->service->name,
state->kr->srv == NULL ? true : false);
if (!subreq) {
DEBUG(SSSDBG_CRIT_FAILURE, ("Failed resolver request.\n"));
ret = EIO;
goto done;
}
tevent_req_set_callback(subreq, krb5_auth_resolve_done, req);
return req;
done:
if (ret == EOK) {
tevent_req_done(req);
} else {
tevent_req_error(req, ret);
}
tevent_req_post(req, state->ev);
return req;
}
static void krb5_auth_resolve_done(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(subreq, struct tevent_req);
struct krb5_auth_state *state = tevent_req_data(req, struct krb5_auth_state);
struct krb5child_req *kr = state->kr;
char *msg;
int ret;
if (!state->search_kpasswd) {
ret = be_resolve_server_recv(subreq, &kr->srv);
} else {
ret = be_resolve_server_recv(subreq, &kr->kpasswd_srv);
}
talloc_zfree(subreq);
if (state->search_kpasswd) {
if ((ret != EOK) &&
(kr->pd->cmd == SSS_PAM_CHAUTHTOK ||
kr->pd->cmd == SSS_PAM_CHAUTHTOK_PRELIM)) {
/* all kpasswd servers have been tried and none was found good,
* but the kdc seems ok. Password changes are not possible but
* authentication is. We return an PAM error here, but do not
* mark the backend offline. */
state->pam_status = PAM_AUTHTOK_LOCK_BUSY;
state->dp_err = DP_ERR_OK;
ret = EOK;
goto done;
}
} else {
if (ret != EOK) {
/* all servers have been tried and none
* was found good, setting offline,
* but we still have to call the child to setup
* the ccache file if we are performing auth */
be_mark_offline(state->be_ctx);
kr->is_offline = true;
if (kr->pd->cmd == SSS_PAM_CHAUTHTOK ||
kr->pd->cmd == SSS_PAM_CHAUTHTOK_PRELIM) {
DEBUG(SSSDBG_TRACE_FUNC,
("No KDC suitable for password change is available\n"));
state->pam_status = PAM_AUTHTOK_LOCK_BUSY;
state->dp_err = DP_ERR_OK;
ret = EOK;
goto done;
}
} else {
if (kr->krb5_ctx->kpasswd_service != NULL) {
state->search_kpasswd = true;
subreq = be_resolve_server_send(state,
state->ev, state->be_ctx,
state->krb5_ctx->kpasswd_service->name,
kr->kpasswd_srv == NULL ? true : false);
if (subreq == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE, ("Resolver request failed.\n"));
ret = EIO;
goto done;
}
tevent_req_set_callback(subreq, krb5_auth_resolve_done, req);
return;
}
}
}
ret = krb5_auth_prepare_ccache_file(kr, state->be_ctx,
&state->pam_status, &state->dp_err);
if (ret) {
goto done;
}
if (kr->is_offline) {
DEBUG(9, ("Preparing for offline operation.\n"));
if (kr->valid_tgt || kr->active_ccache) {
DEBUG(9, ("Valid TGT available or "
"ccache file is already in use.\n"));
kr->ccname = kr->old_ccname;
msg = talloc_asprintf(kr->pd,
"%s=%s", CCACHE_ENV_NAME, kr->ccname);
if (msg == NULL) {
DEBUG(1, ("talloc_asprintf failed.\n"));
} else {
ret = pam_add_response(kr->pd, SSS_PAM_ENV_ITEM,
strlen(msg) + 1, (uint8_t *) msg);
if (ret != EOK) {
DEBUG(1, ("pam_add_response failed.\n"));
}
}
if (dp_opt_get_bool(kr->krb5_ctx->opts,
KRB5_STORE_PASSWORD_IF_OFFLINE)) {
krb5_auth_cache_creds(state->kr->krb5_ctx,
state->be_ctx->sysdb,
state->be_ctx->cdb,
kr->pd, kr->uid,
&state->pam_status, &state->dp_err);
} else {
state->pam_status = PAM_AUTHINFO_UNAVAIL;
state->dp_err = DP_ERR_OFFLINE;
}
ret = EOK;
goto done;
}
}
/* We need to keep the root privileges to read the keytab file if
* validation or FAST is enabled, otherwise we can drop them and run
* krb5_child with user privileges.
* If we are offline we want to create an empty ccache file. In this
* case we can drop the privileges, too. */
if ((dp_opt_get_bool(kr->krb5_ctx->opts, KRB5_VALIDATE) ||
kr->krb5_ctx->use_fast) &&
(!kr->is_offline)) {
kr->run_as_user = false;
} else {
kr->run_as_user = true;
}
subreq = handle_child_send(state, state->ev, kr);
if (subreq == NULL) {
DEBUG(1, ("handle_child_send failed.\n"));
ret = ENOMEM;
goto done;
}
tevent_req_set_callback(subreq, krb5_auth_done, req);
return;
done:
if (ret == EOK) {
tevent_req_done(req);
} else {
tevent_req_error(req, ret);
}
}
static void krb5_auth_done(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(subreq, struct tevent_req);
struct krb5_auth_state *state = tevent_req_data(req, struct krb5_auth_state);
struct krb5child_req *kr = state->kr;
struct pam_data *pd = state->pd;
int ret;
uint8_t *buf = NULL;
ssize_t len = -1;
struct krb5_child_response *res;
const char *store_ccname;
struct fo_server *search_srv;
ret = handle_child_recv(subreq, pd, &buf, &len);
talloc_zfree(subreq);
if (ret == ETIMEDOUT) {
DEBUG(1, ("child timed out!\n"));
switch (pd->cmd) {
case SSS_PAM_AUTHENTICATE:
case SSS_CMD_RENEW:
state->search_kpasswd = false;
search_srv = kr->srv;
break;
case SSS_PAM_CHAUTHTOK:
case SSS_PAM_CHAUTHTOK_PRELIM:
if (state->kr->kpasswd_srv) {
state->search_kpasswd = true;
search_srv = kr->kpasswd_srv;
break;
} else {
state->search_kpasswd = false;
search_srv = kr->srv;
break;
}
default:
DEBUG(1, ("Unexpected PAM task\n"));
ret = EINVAL;
goto done;
}
be_fo_set_port_status(state->be_ctx, state->krb5_ctx->service->name,
search_srv, PORT_NOT_WORKING);
subreq = be_resolve_server_send(state, state->ev, state->be_ctx,
state->krb5_ctx->kpasswd_service->name,
search_srv == NULL ? true : false);
if (subreq == NULL) {
DEBUG(1, ("Failed resolved request.\n"));
ret = ENOMEM;
goto done;
}
tevent_req_set_callback(subreq, krb5_auth_resolve_done, req);
return;
} else if (ret != EOK) {
DEBUG(1, ("child failed (%d [%s])\n", ret, strerror(ret)));
goto done;
}
/* EOK */
ret = parse_krb5_child_response(state, buf, len, pd,
state->be_ctx->domain->pwd_expiration_warning,
&res);
if (ret) {
DEBUG(SSSDBG_OP_FAILURE, ("Could not parse child response [%d]: %s\n",
ret, strerror(ret)));
goto done;
}
if (res->ccname) {
kr->ccname = talloc_strdup(kr, res->ccname);
if (!kr->ccname) {
ret = ENOMEM;
goto done;
}
}
/* Check if the cases of our upn are correct and update it if needed.
* Fail if the upn differs by more than just the case. */
if (res->correct_upn != NULL &&
strcmp(kr->upn, res->correct_upn) != 0) {
if (strcasecmp(kr->upn, res->correct_upn) == 0) {
talloc_free(kr->upn);
kr->upn = talloc_strdup(kr, res->correct_upn);
if (kr->upn == NULL) {
DEBUG(SSSDBG_OP_FAILURE, ("talloc_strdup failed.\n"));
ret = ENOMEM;
goto done;
}
ret = check_if_cached_upn_needs_update(state->sysdb, state->domain,
pd->user, res->correct_upn);
if (ret != EOK) {
DEBUG(SSSDBG_OP_FAILURE,
("check_if_cached_upn_needs_update failed.\n"));
goto done;
}
} else {
DEBUG(SSSDBG_CRIT_FAILURE, ("UPN used in the request [%s] and " \
"returned UPN [%s] differ by more " \
"than just the case.\n",
kr->upn, res->correct_upn));
ret = EINVAL;
goto done;
}
}
/* If the child request failed, but did not return an offline error code,
* return with the status */
if (res->msg_status != PAM_SUCCESS &&
res->msg_status != PAM_AUTHINFO_UNAVAIL &&
res->msg_status != PAM_AUTHTOK_LOCK_BUSY &&
res->msg_status != PAM_NEW_AUTHTOK_REQD) {
state->pam_status = res->msg_status;
state->dp_err = DP_ERR_OK;
ret = EOK;
goto done;
} else {
state->pam_status = res->msg_status;
}
/* If the password is expired we can safely remove the ccache from the
* cache and disk if it is not actively used anymore. This will allow to
* create a new random ccache if sshd with privilege separation is used. */
if (res->msg_status == PAM_NEW_AUTHTOK_REQD) {
if (pd->cmd == SSS_PAM_AUTHENTICATE && !kr->active_ccache) {
if (kr->old_ccname != NULL) {
ret = safe_remove_old_ccache_file(kr->cc_be, kr->upn,
kr->old_ccname, "dummy");
if (ret != EOK) {
DEBUG(1, ("Failed to remove old ccache file [%s], "
"please remove it manually.\n", kr->old_ccname));
}
ret = krb5_delete_ccname(state, state->sysdb, state->domain,
pd->user, kr->old_ccname);
if (ret != EOK) {
DEBUG(1, ("krb5_delete_ccname failed.\n"));
}
}
}
state->pam_status = res->msg_status;
state->dp_err = DP_ERR_OK;
ret = EOK;
goto done;
}
/* If the child request was successful and we run the first pass of the
* change password request just return success. */
if (res->msg_status == PAM_SUCCESS && pd->cmd == SSS_PAM_CHAUTHTOK_PRELIM) {
state->pam_status = PAM_SUCCESS;
state->dp_err = DP_ERR_OK;
ret = EOK;
goto done;
}
/* if using a dedicated kpasswd server for a chpass operation... */
if (kr->kpasswd_srv != NULL &&
(pd->cmd == SSS_PAM_CHAUTHTOK || pd->cmd == SSS_PAM_CHAUTHTOK_PRELIM)) {
/* ..which is unreachable by now.. */
if (res->msg_status == PAM_AUTHTOK_LOCK_BUSY) {
be_fo_set_port_status(state->be_ctx,
state->krb5_ctx->kpasswd_service->name,
kr->kpasswd_srv, PORT_NOT_WORKING);
/* ..try to resolve next kpasswd server */
state->search_kpasswd = true;
subreq = be_resolve_server_send(state, state->ev, state->be_ctx,
state->krb5_ctx->kpasswd_service->name,
state->kr->kpasswd_srv == NULL ? true : false);
if (subreq == NULL) {
DEBUG(1, ("Resolver request failed.\n"));
ret = ENOMEM;
goto done;
}
tevent_req_set_callback(subreq, krb5_auth_resolve_done, req);
return;
} else {
be_fo_set_port_status(state->be_ctx,
state->krb5_ctx->kpasswd_service->name,
kr->kpasswd_srv, PORT_WORKING);
}
}
/* if the KDC for auth (PAM_AUTHINFO_UNAVAIL) or
* chpass (PAM_AUTHTOK_LOCK_BUSY) was not available while using KDC
* also for chpass operation... */
if (res->msg_status == PAM_AUTHINFO_UNAVAIL ||
(kr->kpasswd_srv == NULL && res->msg_status == PAM_AUTHTOK_LOCK_BUSY)) {
if (kr->srv != NULL) {
be_fo_set_port_status(state->be_ctx, state->krb5_ctx->service->name,
kr->srv, PORT_NOT_WORKING);
/* ..try to resolve next KDC */
state->search_kpasswd = false;
subreq = be_resolve_server_send(state, state->ev, state->be_ctx,
state->krb5_ctx->service->name,
kr->srv == NULL ? true : false);
if (subreq == NULL) {
DEBUG(1, ("Resolver request failed.\n"));
ret = ENOMEM;
goto done;
}
tevent_req_set_callback(subreq, krb5_auth_resolve_done, req);
return;
}
} else if (kr->srv != NULL) {
be_fo_set_port_status(state->be_ctx, state->krb5_ctx->service->name,
kr->srv, PORT_WORKING);
}
/* Now only a successful authentication or password change is left.
*
* We expect that one of the messages in the received buffer contains
* the name of the credential cache file. */
if (kr->ccname == NULL) {
DEBUG(1, ("Missing ccache name in child response.\n"));
ret = EINVAL;
goto done;
}
store_ccname = kr->cc_be->ccache_for_princ(kr, kr->ccname,
kr->upn);
if (store_ccname == NULL) {
DEBUG(SSSDBG_CRIT_FAILURE,
("No ccache for %s in %s?\n", kr->upn, kr->ccname));
ret = EIO;
goto done;
}
ret = safe_remove_old_ccache_file(kr->cc_be, kr->upn,
kr->old_ccname, store_ccname);
if (ret != EOK) {
DEBUG(SSSDBG_MINOR_FAILURE,
("Failed to remove old ccache file [%s], "
"please remove it manually.\n", kr->old_ccname));
}
ret = krb5_save_ccname(state, state->sysdb, state->domain,
pd->user, store_ccname);
if (ret) {
DEBUG(1, ("krb5_save_ccname failed.\n"));
goto done;
}
if (res->msg_status == PAM_SUCCESS &&
dp_opt_get_int(kr->krb5_ctx->opts, KRB5_RENEW_INTERVAL) > 0 &&
(pd->cmd == SSS_PAM_AUTHENTICATE || pd->cmd == SSS_CMD_RENEW ||
pd->cmd == SSS_PAM_CHAUTHTOK) &&
res->tgtt.renew_till > res->tgtt.endtime && kr->ccname != NULL) {
DEBUG(7, ("Adding [%s] for automatic renewal.\n", kr->ccname));
ret = add_tgt_to_renew_table(kr->krb5_ctx, kr->ccname, &(res->tgtt),
pd, kr->upn);
if (ret != EOK) {
DEBUG(1, ("add_tgt_to_renew_table failed, "
"automatic renewal not possible.\n"));
}
}
if (kr->is_offline) {
if (dp_opt_get_bool(kr->krb5_ctx->opts,
KRB5_STORE_PASSWORD_IF_OFFLINE)) {
krb5_auth_cache_creds(state->kr->krb5_ctx,
state->be_ctx->sysdb,
state->be_ctx->cdb,
state->pd, state->kr->uid,
&state->pam_status, &state->dp_err);
} else {
DEBUG(4, ("Backend is marked offline, retry later!\n"));
state->pam_status = PAM_AUTHINFO_UNAVAIL;
state->dp_err = DP_ERR_OFFLINE;
}
ret = EOK;
goto done;
}
if (state->be_ctx->domain->cache_credentials == TRUE) {
krb5_auth_store_creds(state->sysdb, state->domain, pd);
}
state->pam_status = PAM_SUCCESS;
state->dp_err = DP_ERR_OK;
ret = EOK;
done:
if (ret == EOK) {
tevent_req_done(req);
} else {
tevent_req_error(req, ret);
}
}
int krb5_auth_recv(struct tevent_req *req, int *pam_status, int *dp_err)
{
struct krb5_auth_state *state = tevent_req_data(req, struct krb5_auth_state);
*pam_status = state->pam_status;
*dp_err = state->dp_err;
TEVENT_REQ_RETURN_ON_ERROR(req);
return EOK;
}
static void krb_reply(struct be_req *req, int dp_err, int result)
{
req->fn(req, dp_err, result, NULL);
}
void krb5_pam_handler_auth_done(struct tevent_req *req);
static void krb5_pam_handler_access_done(struct tevent_req *req);
void krb5_pam_handler(struct be_req *be_req)
{
struct tevent_req *req;
struct pam_data *pd;
struct krb5_ctx *krb5_ctx;
int dp_err = DP_ERR_FATAL;
int ret;
pd = talloc_get_type(be_req->req_data, struct pam_data);
pd->pam_status = PAM_SYSTEM_ERR;
krb5_ctx = get_krb5_ctx(be_req);
if (krb5_ctx == NULL) {
DEBUG(1, ("Kerberos context not available.\n"));
goto done;
}
switch (pd->cmd) {
case SSS_PAM_AUTHENTICATE:
case SSS_CMD_RENEW:
case SSS_PAM_CHAUTHTOK_PRELIM:
case SSS_PAM_CHAUTHTOK:
ret = add_to_wait_queue(be_req, pd, krb5_ctx);
if (ret == EOK) {
DEBUG(7, ("Request successfully added to wait queue "
"of user [%s].\n", pd->user));
return;
} else if (ret == ENOENT) {
DEBUG(7, ("Wait queue of user [%s] is empty, "
"running request immediately.\n", pd->user));
} else {
DEBUG(7, ("Failed to add request to wait queue of user [%s], "
"running request immediately.\n", pd->user));
}
req = krb5_auth_send(be_req, be_req->be_ctx->ev, be_req->be_ctx, pd,
krb5_ctx);
if (req == NULL) {
DEBUG(1, ("krb5_auth_send failed.\n"));
goto done;
}
tevent_req_set_callback(req, krb5_pam_handler_auth_done, be_req);
break;
case SSS_PAM_ACCT_MGMT:
req = krb5_access_send(be_req, be_req->be_ctx->ev, be_req->be_ctx,
pd, krb5_ctx);
if (req == NULL) {
DEBUG(1, ("krb5_access_send failed.\n"));
goto done;
}
tevent_req_set_callback(req, krb5_pam_handler_access_done, be_req);
break;
case SSS_PAM_SETCRED:
case SSS_PAM_OPEN_SESSION:
case SSS_PAM_CLOSE_SESSION:
pd->pam_status = PAM_SUCCESS;
dp_err = DP_ERR_OK;
goto done;
break;
default:
DEBUG(4, ("krb5 does not handles pam task %d.\n", pd->cmd));
pd->pam_status = PAM_MODULE_UNKNOWN;
dp_err = DP_ERR_OK;
goto done;
}
return;
done:
krb_reply(be_req, dp_err, pd->pam_status);
}
void krb5_pam_handler_auth_done(struct tevent_req *req)
{
int ret;
struct be_req *be_req = tevent_req_callback_data(req, struct be_req);
int pam_status;
int dp_err;
struct pam_data *pd;
struct krb5_ctx *krb5_ctx;
pd = talloc_get_type(be_req->req_data, struct pam_data);
ret = krb5_auth_recv(req, &pam_status, &dp_err);
talloc_zfree(req);
if (ret) {
pd->pam_status = PAM_SYSTEM_ERR;
dp_err = DP_ERR_OK;
} else {
pd->pam_status = pam_status;
}
krb5_ctx = get_krb5_ctx(be_req);
if (krb5_ctx != NULL) {
check_wait_queue(krb5_ctx, pd->user);
} else {
DEBUG(1, ("Kerberos context not available.\n"));
}
krb_reply(be_req, dp_err, pd->pam_status);
}
static void krb5_pam_handler_access_done(struct tevent_req *req)
{
int ret;
struct be_req *be_req = tevent_req_callback_data(req, struct be_req);
bool access_allowed;
struct pam_data *pd;
int dp_err = DP_ERR_OK;
pd = talloc_get_type(be_req->req_data, struct pam_data);
pd->pam_status = PAM_SYSTEM_ERR;
ret = krb5_access_recv(req, &access_allowed);
talloc_zfree(req);
if (ret != EOK) {
DEBUG(1, ("krb5_access request failed [%d][%s]\n", ret, strerror(ret)));
goto done;
}
DEBUG(7, ("Access %s for user [%s].\n",
access_allowed ? "allowed" : "denied", pd->user));
pd->pam_status = access_allowed ? PAM_SUCCESS : PAM_PERM_DENIED;
dp_err = DP_ERR_OK;
done:
krb_reply(be_req, dp_err, pd->pam_status);
}