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/*
File: acl_check.c
Copyright (C) 1999, 2000
Andreas Gruenbacher, <a.gruenbacher@computer.org>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <errno.h>
#include <acl/libacl.h>
#include "libacl.h"
#define FAIL_CHECK(error) \
do { return error; } while (0)
/*
Check if an ACL is valid.
The e_id fields of ACL entries that don't use them are ignored.
last
contains the index of the last valid entry found
after acl_check returns.
returns
0 on success, -1 on error, or an ACL_*_ERROR value for invalid ACLs.
*/
int
acl_check(
acl_t acl,
int *last)
{
acl_obj *acl_obj_p = ext2int(acl, acl);
id_t qual = 0;
int state = ACL_USER_OBJ;
acl_entry_obj *entry_obj_p;
int needs_mask = 0;
if (!acl_obj_p)
return -1;
if (last)
*last = 0;
FOREACH_ACL_ENTRY(entry_obj_p, acl_obj_p) {
/* Check permissions for ~(ACL_READ|ACL_WRITE|ACL_EXECUTE) */
switch (entry_obj_p->etag) {
case ACL_USER_OBJ:
if (state == ACL_USER_OBJ) {
qual = 0;
state = ACL_USER;
break;
}
FAIL_CHECK(ACL_MULTI_ERROR);
case ACL_USER:
if (state != ACL_USER)
FAIL_CHECK(ACL_MISS_ERROR);
if (qualifier_obj_id(entry_obj_p->eid) < qual ||
qualifier_obj_id(entry_obj_p->eid) ==
ACL_UNDEFINED_ID)
FAIL_CHECK(ACL_DUPLICATE_ERROR);
qual = qualifier_obj_id(entry_obj_p->eid)+1;
needs_mask = 1;
break;
case ACL_GROUP_OBJ:
if (state == ACL_USER) {
qual = 0;
state = ACL_GROUP;
break;
}
if (state >= ACL_GROUP)
FAIL_CHECK(ACL_MULTI_ERROR);
FAIL_CHECK(ACL_MISS_ERROR);
case ACL_GROUP:
if (state != ACL_GROUP)
FAIL_CHECK(ACL_MISS_ERROR);
if (qualifier_obj_id(entry_obj_p->eid) < qual ||
qualifier_obj_id(entry_obj_p->eid) ==
ACL_UNDEFINED_ID)
FAIL_CHECK(ACL_DUPLICATE_ERROR);
qual = qualifier_obj_id(entry_obj_p->eid)+1;
needs_mask = 1;
break;
case ACL_MASK:
if (state == ACL_GROUP) {
state = ACL_OTHER;
break;
}
if (state >= ACL_OTHER)
FAIL_CHECK(ACL_MULTI_ERROR);
FAIL_CHECK(ACL_MISS_ERROR);
case ACL_OTHER:
if (state == ACL_OTHER ||
(state == ACL_GROUP && !needs_mask)) {
state = 0;
break;
}
FAIL_CHECK(ACL_MISS_ERROR);
default:
FAIL_CHECK(ACL_ENTRY_ERROR);
}
if (last)
(*last)++;
}
if (state != 0)
FAIL_CHECK(ACL_MISS_ERROR);
return 0;
}
#undef FAIL_CHECK
|
