path: root/src/providers/ipa/ipa_selinux.c

/*
    SSSD

    IPA Backend Module -- selinux loading

    Authors:
        Jan Zeleny <jzeleny@redhat.com>

    Copyright (C) 2012 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 <selinux/selinux.h>
#include <security/pam_modules.h>

#include "db/sysdb_selinux.h"
#include "util/sss_selinux.h"
#include "providers/ldap/sdap_async.h"
#include "providers/ipa/ipa_common.h"
#include "providers/ipa/ipa_config.h"
#include "providers/ipa/ipa_selinux.h"
#include "providers/ipa/ipa_hosts.h"
#include "providers/ipa/ipa_hbac_rules.h"
#include "providers/ipa/ipa_hbac_private.h"
#include "providers/ipa/ipa_access.h"
#include "providers/ipa/ipa_selinux_common.h"
#include "providers/ipa/ipa_selinux_maps.h"

#ifdef HAVE_SELINUX_LOGIN_DIR

static struct tevent_req *
ipa_get_selinux_send(TALLOC_CTX *mem_ctx,
                     struct be_ctx *be_ctx,
                     struct sysdb_attrs *user,
                     struct sysdb_attrs *host,
                     struct ipa_selinux_ctx *selinux_ctx);
static errno_t ipa_get_selinux_recv(struct tevent_req *req,
                                    TALLOC_CTX *mem_ctx,
                                    size_t *count,
                                    struct sysdb_attrs ***maps,
                                    size_t *hbac_count,
                                    struct sysdb_attrs ***hbac_rules,
                                    char **default_user,
                                    char **map_order);

static struct ipa_selinux_op_ctx *
ipa_selinux_create_op_ctx(TALLOC_CTX *mem_ctx, struct sysdb_ctx *sysdb,
                          struct sss_domain_info *domain,
                          struct be_req *be_req, const char *username,
                          const char *hostname,
                          struct ipa_selinux_ctx *selinux_ctx);
static void ipa_selinux_handler_done(struct tevent_req *subreq);

static void ipa_get_selinux_connect_done(struct tevent_req *subreq);
static void ipa_get_selinux_hosts_done(struct tevent_req *subreq);
static void ipa_get_config_step(struct tevent_req *req);
static void ipa_get_selinux_config_done(struct tevent_req *subreq);
static void ipa_get_selinux_maps_done(struct tevent_req *subreq);
static void ipa_get_selinux_hbac_done(struct tevent_req *subreq);
static errno_t ipa_selinux_process_maps(TALLOC_CTX *mem_ctx,
                                        struct sysdb_attrs *user,
                                        struct sysdb_attrs *host,
                                        struct sysdb_attrs **selinux_maps,
                                        size_t selinux_map_count,
                                        struct sysdb_attrs **hbac_rules,
                                        size_t hbac_rule_count,
                                        struct sysdb_attrs ***usermaps);

struct ipa_selinux_op_ctx {
    struct be_req *be_req;
    struct sss_domain_info *domain;
    struct ipa_selinux_ctx *selinux_ctx;

    struct sysdb_attrs *user;
    struct sysdb_attrs *host;
};

void ipa_selinux_handler(struct be_req *be_req)
{
    struct be_ctx *be_ctx = be_req_get_be_ctx(be_req);
    struct ipa_selinux_ctx *selinux_ctx;
    struct ipa_selinux_op_ctx *op_ctx;
    struct tevent_req *req;
    struct pam_data *pd;
    const char *hostname;

    pd = talloc_get_type(be_req_get_data(be_req), struct pam_data);

    selinux_ctx = talloc_get_type(be_ctx->bet_info[BET_SELINUX].pvt_bet_data,
                                  struct ipa_selinux_ctx);

    hostname = dp_opt_get_string(selinux_ctx->id_ctx->ipa_options->basic,
                                 IPA_HOSTNAME);
    if (!hostname) {
        DEBUG(SSSDBG_OP_FAILURE, ("Cannot determine this machine's host name\n"));
        goto fail;
    }

    op_ctx = ipa_selinux_create_op_ctx(be_req, be_ctx->domain->sysdb,
                                       be_ctx->domain,
                                       be_req, pd->user, hostname,
                                       selinux_ctx);
    if (op_ctx == NULL) {
        DEBUG(SSSDBG_OP_FAILURE, ("Cannot create op context\n"));
        goto fail;
    }

    req = ipa_get_selinux_send(be_req, be_ctx,
                               op_ctx->user, op_ctx->host, selinux_ctx);
    if (req == NULL) {
        DEBUG(SSSDBG_OP_FAILURE, ("Cannot initiate the search\n"));
        goto fail;
    }

    tevent_req_set_callback(req, ipa_selinux_handler_done, op_ctx);
    return;

fail:
    be_req_terminate(be_req, DP_ERR_FATAL, PAM_SYSTEM_ERR, NULL);
}

static struct ipa_selinux_op_ctx *
ipa_selinux_create_op_ctx(TALLOC_CTX *mem_ctx, struct sysdb_ctx *sysdb,
                          struct sss_domain_info *domain,
                          struct be_req *be_req, const char *username,
                          const char *hostname,
                          struct ipa_selinux_ctx *selinux_ctx)
{
    struct ipa_selinux_op_ctx *op_ctx;
    struct ldb_dn *host_dn;
    const char *attrs[] = { SYSDB_ORIG_DN,
                            SYSDB_ORIG_MEMBEROF,
                            NULL };
    size_t count;
    struct ldb_message **msgs;
    struct sysdb_attrs **hosts;
    errno_t ret;

    op_ctx = talloc_zero(mem_ctx, struct ipa_selinux_op_ctx);
    if (op_ctx == NULL) {
        return NULL;
    }
    op_ctx->be_req = be_req;
    op_ctx->domain = domain;
    op_ctx->selinux_ctx = selinux_ctx;

    ret = sss_selinux_extract_user(op_ctx, sysdb, domain, username, &op_ctx->user);
    if (ret != EOK) {
        goto fail;
    }

    host_dn = sysdb_custom_dn(sysdb, op_ctx, domain, hostname, HBAC_HOSTS_SUBDIR);
    if (host_dn == NULL) {
        goto fail;
    }

    /* Look up the host to get its originalMemberOf entries */
    ret = sysdb_search_entry(op_ctx, sysdb, host_dn,
                             LDB_SCOPE_BASE, NULL,
                             attrs, &count, &msgs);
    if (ret == ENOENT || count == 0) {
        op_ctx->host = NULL;
        return op_ctx;
    } else if (ret != EOK) {
        goto fail;
    } else if (count > 1) {
        DEBUG(SSSDBG_OP_FAILURE, ("More than one result for a BASE search!\n"));
        goto fail;
    }

    ret = sysdb_msg2attrs(op_ctx, count, msgs, &hosts);
    talloc_free(msgs);
    if (ret != EOK) {
        goto fail;
    }

    op_ctx->host = hosts[0];
    return op_ctx;

fail:
    talloc_free(op_ctx);
    return NULL;
}

static errno_t create_order_array(TALLOC_CTX *mem_ctx, const char *map_order,
                                  char ***_order_array, size_t *_order_count);
static errno_t choose_best_seuser(struct sysdb_attrs **usermaps,
                                  struct pam_data *pd,
                                  char **order_array, int order_count,
                                  const char *default_user);


static void ipa_selinux_handler_done(struct tevent_req *req)
{
    struct ipa_selinux_op_ctx *op_ctx = tevent_req_callback_data(req, struct ipa_selinux_op_ctx);
    struct be_req *breq = op_ctx->be_req;
    struct be_ctx *be_ctx = be_req_get_be_ctx(breq);
    struct sysdb_ctx *sysdb = op_ctx->domain->sysdb;
    errno_t ret, sret;
    size_t map_count = 0;
    struct sysdb_attrs **maps = NULL;
    bool in_transaction = false;
    char *default_user = NULL;
    struct pam_data *pd =
                    talloc_get_type(be_req_get_data(breq), struct pam_data);
    char *map_order = NULL;
    size_t hbac_count = 0;
    struct sysdb_attrs **hbac_rules = 0;
    struct sysdb_attrs **best_match_maps;
    size_t order_count;
    char **order_array;

    ret = ipa_get_selinux_recv(req, breq, &map_count, &maps,
                               &hbac_count, &hbac_rules,
                               &default_user, &map_order);
    if (ret != EOK) {
        goto fail;
    }

    /* Process the maps and return list of best matches (maps with
     * highest priority). The input maps are also parent memory
     * context for the output list of best matches. The best match
     * maps should never be freed explicitly but always through
     * their parent (or any indirect parent) */
    ret = ipa_selinux_process_maps(maps, op_ctx->user, op_ctx->host,
                                   maps, map_count,
                                   hbac_rules, hbac_count, &best_match_maps);
    if (ret != EOK) {
        goto fail;
    }

    ret = create_order_array(op_ctx, map_order,
                             &order_array, &order_count);
    if (ret != EOK) {
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("Failed to create ordered SELinux users array.\n"));
        goto fail;
    }

    ret = choose_best_seuser(best_match_maps, pd, order_array, order_count,
                             default_user);
    if (ret != EOK) {
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("Failed to evaluate ordered SELinux users array.\n"));
        goto fail;
    }

    ret = sysdb_transaction_start(sysdb);
    if (ret != EOK) {
        DEBUG(SSSDBG_CRIT_FAILURE, ("Failed to start transaction\n"));
        goto fail;
    }
    in_transaction = true;

    ret = sysdb_delete_usermaps(op_ctx->domain->sysdb, op_ctx->domain);
    if (ret != EOK) {
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("Cannot delete existing maps from sysdb\n"));
        goto fail;
    }

    ret = sysdb_store_selinux_config(sysdb, op_ctx->domain,
                                     default_user, map_order);
    if (ret != EOK) {
        goto fail;
    }

    if (map_count > 0 && maps != NULL) {
        ret = ipa_save_user_maps(sysdb, op_ctx->domain, map_count, maps);
        if (ret != EOK) {
            goto fail;
        }
    }

    ret = sysdb_transaction_commit(sysdb);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("Could not commit transaction\n"));
        goto fail;
    }
    in_transaction = false;

    /* If we got here in online mode, set last_update to current time */
    if (!be_is_offline(be_ctx)) {
        op_ctx->selinux_ctx->last_update = time(NULL);
    }

    pd->pam_status = PAM_SUCCESS;
    be_req_terminate(breq, DP_ERR_OK, EOK, "Success");
    return;

fail:
    if (in_transaction) {
        sret = sysdb_transaction_cancel(sysdb);
        if (sret != EOK) {
            DEBUG(SSSDBG_OP_FAILURE, ("Could not cancel transaction\n"));
        }
    }
    if (ret == EAGAIN) {
        be_req_terminate(breq, DP_ERR_OFFLINE, EAGAIN, "Offline");
    } else {
        be_req_terminate(breq, DP_ERR_FATAL, ret, NULL);
    }
}

static errno_t
ipa_selinux_process_seealso_maps(struct sysdb_attrs *user,
                                 struct sysdb_attrs *host,
                                 struct sysdb_attrs **seealso_rules,
                                 size_t seealso_rules_count,
                                 struct sysdb_attrs **hbac_rules,
                                 size_t hbac_rule_count,
                                 uint32_t top_priority,
                                 struct sysdb_attrs **usermaps,
                                 size_t best_match_maps_cnt);
static errno_t
ipa_selinux_process_maps(TALLOC_CTX *mem_ctx,
                         struct sysdb_attrs *user,
                         struct sysdb_attrs *host,
                         struct sysdb_attrs **selinux_maps,
                         size_t selinux_map_count,
                         struct sysdb_attrs **hbac_rules,
                         size_t hbac_rule_count,
                         struct sysdb_attrs ***_usermaps)
{
    TALLOC_CTX *tmp_ctx;
    int i;
    errno_t ret;
    uint32_t priority = 0;
    uint32_t top_priority = 0;
    struct sysdb_attrs **seealso_rules;
    size_t num_seealso_rules = 0;
    const char *seealso_str;
    struct sysdb_attrs **usermaps;
    size_t best_match_maps_cnt = 0;

    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) {
        return ENOMEM;
    }

    seealso_rules = talloc_zero_array(tmp_ctx, struct sysdb_attrs *,
                                      selinux_map_count + 1);
    if (seealso_rules == NULL) {
        ret = ENOMEM;
        goto done;
    }

    usermaps = talloc_zero_array(tmp_ctx, struct sysdb_attrs *, selinux_map_count + 1);
    if (usermaps == NULL) {
        ret = ENOMEM;
        goto done;
    }

    for (i = 0; i < selinux_map_count; i++) {
        if (sss_selinux_match(selinux_maps[i], user, host, &priority)) {
            if (priority < top_priority) {
                /* This rule has lower priority than what we already have,
                 * skip it. */
                continue;
            } else if (priority > top_priority) {
                /* This rule has higher priority, drop what we already have */
                while (best_match_maps_cnt > 0) {
                    best_match_maps_cnt--;
                    usermaps[best_match_maps_cnt] = NULL;
                }
                top_priority = priority;
            }

            usermaps[best_match_maps_cnt] = selinux_maps[i];
            best_match_maps_cnt++;

            continue;
        }

        /* SELinux map did not matched -> check sealso attribute for
         * possible HBAC match */
        ret = sysdb_attrs_get_string(selinux_maps[i],
                                     SYSDB_SELINUX_SEEALSO, &seealso_str);
        if (ret == ENOENT) {
            continue;
        } else if (ret != EOK) {
            goto done;
        }

        seealso_rules[num_seealso_rules] = selinux_maps[i];
        num_seealso_rules++;
    }

    ret = ipa_selinux_process_seealso_maps(user, host,
                                           seealso_rules, num_seealso_rules,
                                           hbac_rules, hbac_rule_count,
                                           top_priority, usermaps, best_match_maps_cnt);
    if (ret != EOK) {
        goto done;
    }

    *_usermaps = talloc_steal(mem_ctx, usermaps);

    ret = EOK;
done:
    talloc_free(tmp_ctx);
    return ret;
}

static errno_t
ipa_selinux_process_seealso_maps(struct sysdb_attrs *user,
                                 struct sysdb_attrs *host,
                                 struct sysdb_attrs **seealso_rules,
                                 size_t seealso_rules_count,
                                 struct sysdb_attrs **hbac_rules,
                                 size_t hbac_rule_count,
                                 uint32_t top_priority,
                                 struct sysdb_attrs **usermaps,
                                 size_t best_match_maps_cnt)
{
    int i, j;
    errno_t ret;
    struct ldb_message_element *el;
    struct sysdb_attrs *usermap;
    const char *seealso_dn;
    const char *hbac_dn;
    uint32_t priority;

    for (i = 0; i < hbac_rule_count; i++) {
        ret = sysdb_attrs_get_string(hbac_rules[i], SYSDB_ORIG_DN, &hbac_dn);
        if (ret != EOK) {
            return ret;
        }

        /* We need to do this translation for further processing. We have to
         * do it manually because no map was used to retrieve HBAC rules.
         */
        ret = sysdb_attrs_get_el(hbac_rules[i], IPA_MEMBER_HOST, &el);
        if (ret != EOK) return ret;
        el->name = SYSDB_ORIG_MEMBER_HOST;

        ret = sysdb_attrs_get_el(hbac_rules[i], IPA_MEMBER_USER, &el);
        if (ret != EOK) return ret;
        el->name = SYSDB_ORIG_MEMBER_USER;

        DEBUG(SSSDBG_TRACE_ALL,
              ("Matching HBAC rule %s with SELinux mappings\n", hbac_dn));

        if (!sss_selinux_match(hbac_rules[i], user, host, &priority)) {
            DEBUG(SSSDBG_TRACE_ALL, ("Rule did not match\n"));
            continue;
        }

        /* HBAC rule matched, find if it is in the "possible" list */
        for (j = 0; j < seealso_rules_count; j++) {
            usermap = seealso_rules[j];
            if (usermap == NULL) {
                continue;
            }

            ret = sysdb_attrs_get_string(usermap, SYSDB_SELINUX_SEEALSO, &seealso_dn);
            if (ret != EOK) {
                return ret;
            }

            if (strcasecmp(hbac_dn, seealso_dn) == 0) {
                DEBUG(SSSDBG_TRACE_FUNC, ("HBAC rule [%s] matched, copying its"
                                          "attributes to SELinux user map [%s]\n",
                                          hbac_dn, seealso_dn));

                /* Selinux maps priority evaluation removed --DELETE this comment before pushing*/
                if (priority < top_priority) {
                    /* This rule has lower priority than what we already have,
                     * skip it. */
                    continue;
                } else if (priority > top_priority) {
                    /* This rule has higher priority, drop what we already have */
                    while (best_match_maps_cnt > 0) {
                        best_match_maps_cnt--;
                        usermaps[best_match_maps_cnt] = NULL;
                    }
                    top_priority = priority;
                }

                usermaps[best_match_maps_cnt] = usermap;
                best_match_maps_cnt++;

                ret = sysdb_attrs_copy_values(hbac_rules[i], usermap, SYSDB_ORIG_MEMBER_USER);
                if (ret != EOK) {
                    return ret;
                }

                ret = sysdb_attrs_copy_values(hbac_rules[i], usermap, SYSDB_USER_CATEGORY);
                if (ret != EOK) {
                    return ret;
                }

                /* Speed up the next iteration */
                seealso_rules[j] = NULL;
            }
        }
    }

    return EOK;
}

static errno_t create_order_array(TALLOC_CTX *mem_ctx, const char *map_order,
                                  char ***_order_array, size_t *_order_count)
{
    TALLOC_CTX *tmp_ctx;
    char *order = NULL;
    char **order_array;
    errno_t ret;
    int i;
    int len;
    size_t order_count;

    tmp_ctx = talloc_new(NULL);
    if (tmp_ctx == NULL) {
        ret = ENOMEM;
        goto done;
    }

    order = talloc_strdup(tmp_ctx, map_order);
    if (order == NULL) {
        ret = ENOMEM;
        goto done;
    }
    len = strlen(order);

    /* The "order" string contains one or more SELinux user records
     * separated by $. Now we need to create an array of string from
     * this one string. First find out how many elements in the array
     * will be. This way only one alloc will be necessary for the array
     */
    order_count = 1;
    for (i = 0; i < len; i++) {
        if (order[i] == '$') order_count++;
    }

    order_array = talloc_array(tmp_ctx, char *, order_count);
    if (order_array == NULL) {
        ret = ENOMEM;
        goto done;
    }

    /* Now fill the array with pointers to the original string. Also
     * use binary zeros to make multiple string out of the one.
     */
    order_array[0] = order;
    order_count = 1;
    for (i = 0; i < len; i++) {
        if (order[i] == '$') {
            order[i] = '\0';
            order_array[order_count] = &order[i+1];
            order_count++;
        }
    }

    *_order_array = talloc_steal(mem_ctx, order_array);
    *_order_count = order_count;

    ret = EOK;
done:
    talloc_free(tmp_ctx);
    return ret;
}

static errno_t write_selinux_login_file(const char *username, char *string);
static errno_t remove_selinux_login_file(const char *username);

/* Choose best selinux user based on given order and write
 * the user to selinux login file. */
static errno_t choose_best_seuser(struct sysdb_attrs **usermaps,
                                  struct pam_data *pd,
                                  char **order_array, int order_count,
                                  const char *default_user)
{
    TALLOC_CTX *tmp_ctx;
    char *file_content = NULL;
    const char *tmp_str;
    errno_t ret, err;
    int i, j;

    tmp_ctx = talloc_new(NULL);
    if (tmp_ctx == NULL) {
        DEBUG(SSSDBG_CRIT_FAILURE, ("talloc_new() failed\n"));
        return ENOMEM;
    }

    /* If no maps match, we'll use the default SELinux user from the
     * config */
    file_content = talloc_strdup(tmp_ctx, default_user);
    if (file_content == NULL) {
        ret = ENOMEM;
        goto done;
    }

    /* Iterate through the order array and try to find SELinux users
     * in fetched maps. The order array contains all SELinux users
     * allowed in the domain in the same order they should appear
     * in the SELinux config file. If any user from the order array
     * is not in fetched user maps, it means it should not be allowed
     * for the user who is just logging in.
     *
     * Right now we have empty content of the SELinux config file,
     * we shall add only those SELinux users that are present both in
     * the order array and user maps applicable to the user who is
     * logging in.
     */
    for (i = 0; i < order_count; i++) {
        for (j = 0; usermaps[j] != NULL; j++) {
            tmp_str = sss_selinux_map_get_seuser(usermaps[j]);

            if (tmp_str && !strcasecmp(tmp_str, order_array[i])) {
                /* If file_content contained something, overwrite it.
                 * This record has higher priority.
                 */
                talloc_zfree(file_content);
                file_content = talloc_strdup(tmp_ctx, tmp_str);
                if (file_content == NULL) {
                    ret = ENOMEM;
                    goto done;
                }
                break;
            }
        }
    }

    ret = write_selinux_login_file(pd->user, file_content);
done:
    if (!file_content) {
        err = remove_selinux_login_file(pd->user);
        /* Don't overwrite original error condition if there was one */
        if (ret == EOK) ret = err;
    }
    talloc_free(tmp_ctx);
    return ret;
}

static errno_t write_selinux_login_file(const char *username, char *string)
{
    char *path = NULL;
    char *tmp_path = NULL;
    ssize_t written;
    int len;
    int fd = -1;
    mode_t oldmask;
    TALLOC_CTX *tmp_ctx;
    char *full_string = NULL;
    int enforce;
    errno_t ret = EOK;

    len = strlen(string);
    if (len == 0) {
        return EINVAL;
    }

    tmp_ctx = talloc_new(NULL);
    if (tmp_ctx == NULL) {
        DEBUG(SSSDBG_CRIT_FAILURE, ("talloc_new() failed\n"));
        return ENOMEM;
    }

    path = selogin_path(tmp_ctx, username);
    if (path == NULL) {
        ret = ENOMEM;
        goto done;
    }

    tmp_path = talloc_asprintf(tmp_ctx, "%sXXXXXX", path);
    if (tmp_path == NULL) {
        ret = ENOMEM;
        goto done;
    }

    oldmask = umask(022);
    fd = mkstemp(tmp_path);
    ret = errno;
    umask(oldmask);
    if (fd < 0) {
        if (ret == ENOENT) {
            /* if selinux is disabled and selogin dir does not exist,
             * just ignore the error */
            if (selinux_getenforcemode(&enforce) == 0 && enforce == -1) {
                ret = EOK;
                goto done;
            }

            /* continue if we can't get enforce mode or selinux is enabled */
        }

        DEBUG(SSSDBG_OP_FAILURE, ("unable to create temp file [%s] "
              "for SELinux data [%d]: %s\n", tmp_path, ret, strerror(ret)));
        goto done;
    }

    full_string = talloc_asprintf(tmp_ctx, "%s:%s", ALL_SERVICES, string);
    if (full_string == NULL) {
        ret = ENOMEM;
        goto done;
    }

    len = strlen(full_string);

    errno = 0;
    written = sss_atomic_write_s(fd, full_string, len);
    if (written == -1) {
        ret = errno;
        DEBUG(SSSDBG_OP_FAILURE, ("writing to SELinux data file %s"
                                  "failed [%d]: %s", tmp_path, ret,
                                  strerror(ret)));
        goto done;
    }

    if (written != len) {
        DEBUG(SSSDBG_OP_FAILURE, ("Expected to write %d bytes, wrote %d",
                                  written, len));
        ret = EIO;
        goto done;
    }

    errno = 0;
    if (rename(tmp_path, path) < 0) {
        ret = errno;
    } else {
        ret = EOK;
    }
    close(fd);
    fd = -1;

done:
    if (fd != -1) {
        close(fd);
        if (unlink(tmp_path) < 0) {
            DEBUG(SSSDBG_MINOR_FAILURE, ("Could not remove file [%s]",
                                         tmp_path));
        }
    }

    talloc_free(tmp_ctx);
    return ret;
}

static errno_t remove_selinux_login_file(const char *username)
{
    char *path;
    errno_t ret;

    path = selogin_path(NULL, username);
    if (!path) return ENOMEM;

    errno = 0;
    ret = unlink(path);
    if (ret < 0) {
        ret = errno;
        if (ret == ENOENT) {
            /* Just return success if the file was not there */
            ret = EOK;
        } else {
            DEBUG(SSSDBG_OP_FAILURE,
                  ("Could not remove login file %s [%d]: %s\n",
                   path, ret, strerror(ret)));
        }
    }

    talloc_free(path);
    return ret;
}


/* A more generic request to gather all SELinux and HBAC rules. Updates
 * cache if necessary
 */
struct ipa_get_selinux_state {
    struct be_ctx *be_ctx;
    struct ipa_selinux_ctx *selinux_ctx;
    struct sdap_id_op *op;

    struct sysdb_attrs *host;
    struct sysdb_attrs *user;

    struct sysdb_attrs *defaults;
    struct sysdb_attrs **selinuxmaps;
    size_t nmaps;

    struct sysdb_attrs **hbac_rules;
    size_t hbac_rule_count;
};

static errno_t
ipa_get_selinux_maps_offline(struct tevent_req *req);

static struct tevent_req *
ipa_get_selinux_send(TALLOC_CTX *mem_ctx,
                     struct be_ctx *be_ctx,
                     struct sysdb_attrs *user,
                     struct sysdb_attrs *host,
                     struct ipa_selinux_ctx *selinux_ctx)
{
    struct tevent_req *req;
    struct tevent_req *subreq;
    struct ipa_get_selinux_state *state;
    bool offline;
    int ret = EOK;
    time_t now;
    time_t refresh_interval;
    struct ipa_options *ipa_options = selinux_ctx->id_ctx->ipa_options;

    DEBUG(SSSDBG_TRACE_FUNC, ("Retrieving SELinux user mapping\n"));
    req = tevent_req_create(mem_ctx, &state, struct ipa_get_selinux_state);
    if (req == NULL) {
        return NULL;
    }

    state->be_ctx = be_ctx;
    state->selinux_ctx = selinux_ctx;
    state->user = user;
    state->host = host;

    offline = be_is_offline(be_ctx);
    DEBUG(SSSDBG_TRACE_INTERNAL, ("Connection status is [%s].\n",
                                  offline ? "offline" : "online"));

    if (!offline) {
        refresh_interval = dp_opt_get_int(ipa_options->basic,
                                          IPA_SELINUX_REFRESH);
        now = time(NULL);
        if (now < selinux_ctx->last_update + refresh_interval) {
            /* SELinux maps were recently updated -> force offline */
            DEBUG(SSSDBG_TRACE_INTERNAL,
                  ("Performing cached SELinux processing\n"));
            offline = true;
        }
    }

    if (!offline) {
        state->op = sdap_id_op_create(state, selinux_ctx->id_ctx->sdap_id_ctx->conn_cache);
        if (!state->op) {
            DEBUG(SSSDBG_OP_FAILURE, ("sdap_id_op_create failed\n"));
            ret = ENOMEM;
            goto immediate;
        }

        subreq = sdap_id_op_connect_send(state->op, state, &ret);
        if (!subreq) {
            DEBUG(SSSDBG_CRIT_FAILURE, ("sdap_id_op_connect_send failed: "
                                        "%d(%s).\n", ret, strerror(ret)));
            talloc_zfree(state->op);
            goto immediate;
        }

        tevent_req_set_callback(subreq, ipa_get_selinux_connect_done, req);
    } else {
        ret = ipa_get_selinux_maps_offline(req);
        goto immediate;
    }

    return req;

immediate:
    if (ret == EOK) {
        tevent_req_done(req);
    } else {
        tevent_req_error(req, ret);
    }
    tevent_req_post(req, be_ctx->ev);
    return req;
}

static void ipa_get_selinux_connect_done(struct tevent_req *subreq)
{
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                  struct tevent_req);
    struct ipa_get_selinux_state *state = tevent_req_data(req,
                                                  struct ipa_get_selinux_state);
    int dp_error = DP_ERR_FATAL;
    int ret;
    struct ipa_id_ctx *id_ctx = state->selinux_ctx->id_ctx;

    const char *access_name;
    const char *selinux_name;
    const char *hostname;

    ret = sdap_id_op_connect_recv(subreq, &dp_error);
    talloc_zfree(subreq);

    if (dp_error == DP_ERR_OFFLINE) {
        talloc_zfree(state->op);
        ret = ipa_get_selinux_maps_offline(req);
        if (ret == EOK) {
            tevent_req_done(req);
            return;
        }
        goto fail;
    }

    if (ret != EOK) {
        goto fail;
    }

    access_name = state->be_ctx->bet_info[BET_ACCESS].mod_name;
    selinux_name = state->be_ctx->bet_info[BET_SELINUX].mod_name;
    if (strcasecmp(access_name, selinux_name) == 0 && state->host != NULL) {
        /* If the access control module is the same as the selinux module
         * and the access control had already discovered the host
         */
        return ipa_get_config_step(req);
    }

    hostname = dp_opt_get_string(state->selinux_ctx->id_ctx->ipa_options->basic,
                                        IPA_HOSTNAME);
    if (hostname == NULL) {
        DEBUG(SSSDBG_CRIT_FAILURE, ("Cannot determine the host name\n"));
        goto fail;
    }

    subreq = ipa_host_info_send(state, state->be_ctx->ev,
                                sdap_id_op_handle(state->op),
                                id_ctx->sdap_id_ctx->opts,
                                hostname,
                                id_ctx->ipa_options->host_map,
                                NULL,
                                state->selinux_ctx->host_search_bases);
    if (subreq == NULL) {
        ret = ENOMEM;
        goto fail;
    }

    tevent_req_set_callback(subreq, ipa_get_selinux_hosts_done, req);
    return;

fail:
    tevent_req_error(req, ret);
}

static errno_t
ipa_get_selinux_maps_offline(struct tevent_req *req)
{
    errno_t ret;
    size_t nmaps;
    struct ldb_message **maps;
    struct ldb_message *defaults;
    const char *attrs[] = { SYSDB_NAME,
                            SYSDB_USER_CATEGORY,
                            SYSDB_HOST_CATEGORY,
                            SYSDB_ORIG_MEMBER_USER,
                            SYSDB_ORIG_MEMBER_HOST,
                            SYSDB_SELINUX_SEEALSO,
                            SYSDB_SELINUX_USER,
                            NULL };
    const char *default_user;
    const char *order;

    struct ipa_get_selinux_state *state = tevent_req_data(req,
                                                  struct ipa_get_selinux_state);

    /* read the config entry */
    ret = sysdb_search_selinux_config(state, state->be_ctx->domain->sysdb,
                                      state->be_ctx->domain, NULL, &defaults);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("sysdb_search_selinux_config failed [%d]: %s\n",
                                  ret, strerror(ret)));
        return ret;
    }

    default_user = ldb_msg_find_attr_as_string(defaults,
                                               SYSDB_SELINUX_DEFAULT_USER,
                                               NULL);
    order = ldb_msg_find_attr_as_string(defaults, SYSDB_SELINUX_DEFAULT_ORDER,
                                        NULL);

    state->defaults = sysdb_new_attrs(state);
    if (state->defaults == NULL) {
        return ENOMEM;
    }

    ret = sysdb_attrs_add_string(state->defaults,
                                 IPA_CONFIG_SELINUX_DEFAULT_USER_CTX,
                                 default_user);
    if (ret != EOK) {
        return ret;
    }

    ret = sysdb_attrs_add_string(state->defaults,
                                 IPA_CONFIG_SELINUX_MAP_ORDER, order);
    if (ret != EOK) {
        return ret;
    }

    /* read all the SELinux rules */
    ret = sysdb_get_selinux_usermaps(state, state->be_ctx->domain->sysdb,
                                     state->be_ctx->domain,
                                     attrs, &nmaps, &maps);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("sysdb_get_selinux_usermaps failed [%d]: %s\n",
                                  ret, strerror(ret)));
        return ret;
    }

    ret = sysdb_msg2attrs(state, nmaps, maps, &state->selinuxmaps);
    if (ret != EOK) {
        return ret;
    }
    state->nmaps = nmaps;

    /* read all the HBAC rules */
    ret = hbac_get_cached_rules(state, state->be_ctx->domain,
                                &state->hbac_rule_count, &state->hbac_rules);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("hbac_get_cached_rules failed [%d]: %s\n",
                                  ret, strerror(ret)));
        return ret;
    }

    return EOK;
}

static void ipa_get_selinux_hosts_done(struct tevent_req *subreq)
{
    errno_t ret;
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                  struct tevent_req);
    struct ipa_get_selinux_state *state = tevent_req_data(req,
                                                  struct ipa_get_selinux_state);
    size_t host_count, hostgroup_count;
    struct sysdb_attrs **hostgroups;
    struct sysdb_attrs **host;

    ret = ipa_host_info_recv(subreq, state, &host_count, &host,
                             &hostgroup_count, &hostgroups);
    talloc_free(subreq);
    if (ret != EOK) {
        goto done;
    }
    state->host = host[0];

    return ipa_get_config_step(req);

done:
    if (ret != EOK) {
        tevent_req_error(req, ret);
    }
}

static void ipa_get_config_step(struct tevent_req *req)
{
    const char *domain;
    struct tevent_req *subreq;
    struct ipa_get_selinux_state *state = tevent_req_data(req,
                                                  struct ipa_get_selinux_state);
    struct ipa_id_ctx *id_ctx = state->selinux_ctx->id_ctx;

    domain = dp_opt_get_string(state->selinux_ctx->id_ctx->ipa_options->basic,
                               IPA_KRB5_REALM);
    subreq = ipa_get_config_send(state, state->be_ctx->ev,
                                 sdap_id_op_handle(state->op),
                                 id_ctx->sdap_id_ctx->opts,
                                 domain, NULL);
    if (subreq == NULL) {
        tevent_req_error(req, ENOMEM);
    }
    tevent_req_set_callback(subreq, ipa_get_selinux_config_done, req);
}

static void ipa_get_selinux_config_done(struct tevent_req *subreq)
{
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                  struct tevent_req);
    struct ipa_get_selinux_state *state = tevent_req_data(req,
                                                  struct ipa_get_selinux_state);
    struct sdap_id_ctx *id_ctx = state->selinux_ctx->id_ctx->sdap_id_ctx;
    errno_t ret;

    ret = ipa_get_config_recv(subreq, state, &state->defaults);
    talloc_free(subreq);
    if (ret != EOK) {
        DEBUG(SSSDBG_OP_FAILURE, ("Could not get IPA config\n"));
        goto done;
    }

    subreq = ipa_selinux_get_maps_send(state, state->be_ctx->ev,
                                       state->be_ctx->domain->sysdb,
                                     sdap_id_op_handle(state->op),
                                     id_ctx->opts,
                                     state->selinux_ctx->id_ctx->ipa_options,
                                     state->selinux_ctx->selinux_search_bases);
    if (!subreq) {
        ret = ENOMEM;
        goto done;
    }
    tevent_req_set_callback(subreq, ipa_get_selinux_maps_done, req);
    return;

done:
    if (ret != EOK) {
        tevent_req_error(req, ret);
    } else {
        tevent_req_done(req);
    }
}

static void ipa_get_selinux_maps_done(struct tevent_req *subreq)
{
    struct tevent_req *req;
    struct ipa_get_selinux_state *state;

    struct ipa_id_ctx *id_ctx;

    char *selinux_name;
    char *access_name;

    const char *tmp_str;
    bool check_hbac;
    errno_t ret;
    int i;

    req = tevent_req_callback_data(subreq, struct tevent_req);
    state = tevent_req_data(req, struct ipa_get_selinux_state);
    id_ctx = state->selinux_ctx->id_ctx;

    ret = ipa_selinux_get_maps_recv(subreq, state,
                                    &state->nmaps, &state->selinuxmaps);
    talloc_free(subreq);
    if (ret != EOK) {
        if (ret == ENOENT) {
            /* This is returned if no SELinux mapping
             * rules were found. In that case no error
             * occurred, but we don't want any more processing.*/
            ret = EOK;
        }
        goto done;
    }

    DEBUG(SSSDBG_TRACE_FUNC,
         ("Found %d SELinux user maps\n", state->nmaps));

    check_hbac = false;
    for (i = 0; i < state->nmaps; i++) {
        ret = sysdb_attrs_get_string(state->selinuxmaps[i],
                                     SYSDB_SELINUX_SEEALSO, &tmp_str);
        if (ret == EOK) {
            check_hbac = true;
            break;
        }
    }

    if (check_hbac) {
        access_name = state->be_ctx->bet_info[BET_ACCESS].mod_name;
        selinux_name = state->be_ctx->bet_info[BET_SELINUX].mod_name;
        if (strcasecmp(access_name, selinux_name) == 0) {
            ret = hbac_get_cached_rules(state, state->be_ctx->domain,
                                        &state->hbac_rule_count,
                                        &state->hbac_rules);
            /* Terminates the request */
            goto done;
        }

        DEBUG(SSSDBG_TRACE_FUNC, ("SELinux maps referenced an HBAC rule. "
              "Need to refresh HBAC rules\n"));
        subreq = ipa_hbac_rule_info_send(state, false, state->be_ctx->ev,
                                         sdap_id_op_handle(state->op),
                                         id_ctx->sdap_id_ctx->opts,
                                         state->selinux_ctx->hbac_search_bases,
                                         state->host);
        if (subreq == NULL) {
            ret = ENOMEM;
            goto done;
        }

        tevent_req_set_callback(subreq, ipa_get_selinux_hbac_done, req);
        return;
    }

    ret = EOK;
done:
    if (ret == EOK) {
        tevent_req_done(req);
    } else {
        tevent_req_error(req, ret);
    }
}

static void ipa_get_selinux_hbac_done(struct tevent_req *subreq)
{
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                      struct tevent_req);
    struct ipa_get_selinux_state *state = tevent_req_data(req,
                                                  struct ipa_get_selinux_state);
    errno_t ret;

    ret = ipa_hbac_rule_info_recv(subreq, state, &state->hbac_rule_count,
                                  &state->hbac_rules);
    DEBUG(SSSDBG_TRACE_INTERNAL,
          ("Received %d HBAC rules\n", state->hbac_rule_count));
    talloc_free(subreq);

    if (ret != EOK) {
        tevent_req_error(req, ret);
    } else {
        tevent_req_done(req);
    }
}

static errno_t
ipa_get_selinux_recv(struct tevent_req *req,
                     TALLOC_CTX *mem_ctx,
                     size_t *count,
                     struct sysdb_attrs ***maps,
                     size_t *hbac_count,
                     struct sysdb_attrs ***hbac_rules,
                     char **default_user,
                     char **map_order)
{
    struct ipa_get_selinux_state *state =
            tevent_req_data(req, struct ipa_get_selinux_state);
    const char *tmp_str;
    errno_t ret;

    TEVENT_REQ_RETURN_ON_ERROR(req);

    if (state->defaults != NULL) {
        ret = sysdb_attrs_get_string(state->defaults,
                                     IPA_CONFIG_SELINUX_DEFAULT_USER_CTX,
                                     &tmp_str);
        if (ret != EOK && ret != ENOENT) {
            return ret;
        }

        if (ret == EOK) {
            *default_user = talloc_strdup(mem_ctx, tmp_str);
            if (*default_user == NULL) {
                return ENOMEM;
            }
        }

        ret = sysdb_attrs_get_string(state->defaults, IPA_CONFIG_SELINUX_MAP_ORDER,
                                     &tmp_str);
        if (ret != EOK) {
            return ret;
        }

        *map_order = talloc_strdup(mem_ctx, tmp_str);
        if (*map_order == NULL) {
            talloc_zfree(*default_user);
            return ENOMEM;
        }
    } else {
        *map_order = NULL;
        *default_user = NULL;
    }

    if (state->selinuxmaps != NULL) {
        *count = state->nmaps;
        *maps = talloc_steal(mem_ctx, state->selinuxmaps);
    } else {
        *count = 0;
        *maps = NULL;
    }

    if (state->hbac_rules != NULL) {
        *hbac_count = state->hbac_rule_count;
        *hbac_rules = talloc_steal(mem_ctx, state->hbac_rules);
    } else {
        *hbac_count = 0;
        *hbac_rules = NULL;
    }

    return EOK;
}

#else
/* Simply return success if HAVE_SELINUX_LOGIN_DIR is not defined. */
void ipa_selinux_handler(struct be_req *be_req)
{
    struct be_ctx *be_ctx = be_req_get_be_ctx(be_req);
    struct pam_data *pd;

    pd = talloc_get_type(be_req_get_data(be_req), struct pam_data);

    pd->pam_status = PAM_SUCCESS;
    be_req_terminate(be_req, DP_ERR_OK, EOK, "Success");
}
#endif