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/*
SSSD
Simple access control
Copyright (C) Sumit Bose <sbose@redhat.com> 2010
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 "providers/simple/simple_access.h"
#include "util/sss_utf8.h"
#include "db/sysdb.h"
errno_t simple_access_check(struct simple_ctx *ctx, const char *username,
bool *access_granted)
{
int i, j;
errno_t ret;
TALLOC_CTX *tmp_ctx = NULL;
const char *user_attrs[] = { SYSDB_MEMBEROF,
SYSDB_GIDNUM,
NULL };
const char *group_attrs[] = { SYSDB_NAME,
NULL };
struct ldb_message *msg;
struct ldb_message_element *el;
char **groups;
const char *primary_group;
gid_t gid;
bool matched;
bool cs = ctx->domain->case_sensitive;
*access_granted = false;
/* First, check whether the user is in the allowed users list */
if (ctx->allow_users != NULL) {
for(i = 0; ctx->allow_users[i] != NULL; i++) {
if (sss_string_equal(cs, username, ctx->allow_users[i])) {
DEBUG(9, ("User [%s] found in allow list, access granted.\n",
username));
/* Do not return immediately on explicit allow
* We need to make sure none of the user's groups
* are denied.
*/
*access_granted = true;
}
}
} else if (!ctx->allow_groups) {
/* If neither allow rule is in place, we'll assume allowed
* unless a deny rule disables us below.
*/
*access_granted = true;
}
/* Next check whether this user has been specifically denied */
if (ctx->deny_users != NULL) {
for(i = 0; ctx->deny_users[i] != NULL; i++) {
if (sss_string_equal(cs, username, ctx->deny_users[i])) {
DEBUG(9, ("User [%s] found in deny list, access denied.\n",
username));
/* Return immediately on explicit denial */
*access_granted = false;
return EOK;
}
}
}
if (!ctx->allow_groups && !ctx->deny_groups) {
/* There are no group restrictions, so just return
* here with whatever we've decided.
*/
return EOK;
}
/* Now get a list of this user's groups and check those against the
* simple_allow_groups list.
*/
tmp_ctx = talloc_new(NULL);
if (!tmp_ctx) {
ret = ENOMEM;
goto done;
}
ret = sysdb_search_user_by_name(tmp_ctx, ctx->domain->sysdb, ctx->domain,
username, user_attrs, &msg);
if (ret != EOK) {
DEBUG(1, ("Could not look up username [%s]: [%d][%s]\n",
username, ret, strerror(ret)));
goto done;
}
/* Construct a list of the user's groups */
el = ldb_msg_find_element(msg, SYSDB_MEMBEROF);
if (el && el->num_values) {
/* Get the groups from the memberOf entries
* Allocate the array with room for both the NULL
* terminator and the primary group
*/
groups = talloc_array(tmp_ctx, char *, el->num_values + 2);
if (!groups) {
ret = ENOMEM;
goto done;
}
for (j = 0; j < el->num_values; j++) {
ret = sysdb_group_dn_name(
ctx->domain->sysdb, tmp_ctx,
(char *)el->values[j].data,
&groups[j]);
if (ret != EOK) {
goto done;
}
}
} else {
/* User is not a member of any groups except primary */
groups = talloc_array(tmp_ctx, char *, 2);
if (!groups) {
ret = ENOMEM;
goto done;
}
j = 0;
}
/* Get the user's primary group */
gid = ldb_msg_find_attr_as_uint64(msg, SYSDB_GIDNUM, 0);
if (!gid) {
ret = EINVAL;
goto done;
}
talloc_zfree(msg);
ret = sysdb_search_group_by_gid(tmp_ctx, ctx->domain->sysdb, ctx->domain,
gid, group_attrs, &msg);
if (ret != EOK) {
DEBUG(1, ("Could not look up primary group [%lu]: [%d][%s]\n",
gid, ret, strerror(ret)));
/* We have to treat this as non-fatal, because the primary
* group may be local to the machine and not available in
* our ID provider.
*/
} else {
primary_group = ldb_msg_find_attr_as_string(msg, SYSDB_NAME, NULL);
if (!primary_group) {
ret = EINVAL;
goto done;
}
groups[j] = talloc_strdup(tmp_ctx, primary_group);
if (!groups[j]) {
ret = ENOMEM;
goto done;
}
j++;
talloc_zfree(msg);
}
groups[j] = NULL;
/* Now process allow and deny group rules
* If access was already granted above, we'll skip
* this redundant rule check
*/
if (ctx->allow_groups && !*access_granted) {
matched = false;
for (i = 0; ctx->allow_groups[i]; i++) {
for(j = 0; groups[j]; j++) {
if (sss_string_equal(cs, groups[j], ctx->allow_groups[i])) {
matched = true;
break;
}
}
/* If any group has matched, we can skip out on the
* processing early
*/
if (matched) {
*access_granted = true;
break;
}
}
}
/* Finally, process the deny group rules */
if (ctx->deny_groups) {
matched = false;
for (i = 0; ctx->deny_groups[i]; i++) {
for(j = 0; groups[j]; j++) {
if (sss_string_equal(cs, groups[j], ctx->deny_groups[i])) {
matched = true;
break;
}
}
/* If any group has matched, we can skip out on the
* processing early
*/
if (matched) {
*access_granted = false;
break;
}
}
}
ret = EOK;
done:
talloc_free(tmp_ctx);
return ret;
}
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