freebsd-skq/lib/libc/posix1e/acl_support.c
Pedro F. Giffuni d915a14ef0 libc: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-25 17:12:48 +00:00

421 lines
9.9 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1999-2001, 2008 Robert N. M. Watson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Support functionality for the POSIX.1e ACL interface
* These calls are intended only to be called within the library.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include "namespace.h"
#include <sys/acl.h>
#include "un-namespace.h"
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "acl_support.h"
#define ACL_STRING_PERM_WRITE 'w'
#define ACL_STRING_PERM_READ 'r'
#define ACL_STRING_PERM_EXEC 'x'
#define ACL_STRING_PERM_NONE '-'
/*
* Return 0, if both ACLs are identical.
*/
int
_acl_differs(const acl_t a, const acl_t b)
{
int i;
struct acl_entry *entrya, *entryb;
assert(_acl_brand(a) == _acl_brand(b));
assert(_acl_brand(a) != ACL_BRAND_UNKNOWN);
assert(_acl_brand(b) != ACL_BRAND_UNKNOWN);
if (a->ats_acl.acl_cnt != b->ats_acl.acl_cnt)
return (1);
for (i = 0; i < b->ats_acl.acl_cnt; i++) {
entrya = &(a->ats_acl.acl_entry[i]);
entryb = &(b->ats_acl.acl_entry[i]);
if (entrya->ae_tag != entryb->ae_tag ||
entrya->ae_id != entryb->ae_id ||
entrya->ae_perm != entryb->ae_perm ||
entrya->ae_entry_type != entryb->ae_entry_type ||
entrya->ae_flags != entryb->ae_flags)
return (1);
}
return (0);
}
/*
* _posix1e_acl_entry_compare -- compare two acl_entry structures to
* determine the order they should appear in. Used by _posix1e_acl_sort to
* sort ACL entries into the kernel-desired order -- i.e., the order useful
* for evaluation and O(n) validity checking. Beter to have an O(nlogn) sort
* in userland and an O(n) in kernel than to have both in kernel.
*/
typedef int (*compare)(const void *, const void *);
static int
_posix1e_acl_entry_compare(struct acl_entry *a, struct acl_entry *b)
{
assert(_entry_brand(a) == ACL_BRAND_POSIX);
assert(_entry_brand(b) == ACL_BRAND_POSIX);
/*
* First, sort between tags -- conveniently defined in the correct
* order for verification.
*/
if (a->ae_tag < b->ae_tag)
return (-1);
if (a->ae_tag > b->ae_tag)
return (1);
/*
* Next compare uids/gids on appropriate types.
*/
if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
if (a->ae_id < b->ae_id)
return (-1);
if (a->ae_id > b->ae_id)
return (1);
/* shouldn't be equal, fall through to the invalid case */
}
/*
* Don't know how to sort multiple entries of the rest--either it's
* a bad entry, or there shouldn't be more than one. Ignore and the
* validity checker can get it later.
*/
return (0);
}
/*
* _posix1e_acl_sort -- sort ACL entries in POSIX.1e-formatted ACLs.
*/
void
_posix1e_acl_sort(acl_t acl)
{
struct acl *acl_int;
acl_int = &acl->ats_acl;
qsort(&acl_int->acl_entry[0], acl_int->acl_cnt,
sizeof(struct acl_entry), (compare) _posix1e_acl_entry_compare);
}
/*
* acl_posix1e -- in what situations should we acl_sort before submission?
* We apply posix1e ACL semantics for any ACL of type ACL_TYPE_ACCESS or
* ACL_TYPE_DEFAULT
*/
int
_posix1e_acl(acl_t acl, acl_type_t type)
{
if (_acl_brand(acl) != ACL_BRAND_POSIX)
return (0);
return ((type == ACL_TYPE_ACCESS) || (type == ACL_TYPE_DEFAULT));
}
/*
* _posix1e_acl_check -- given an ACL, check its validity. This is mirrored
* from code in sys/kern/kern_acl.c, and if changes are made in one, they
* should be made in the other also. This copy of acl_check is made
* available * in userland for the benefit of processes wanting to check ACLs
* for validity before submitting them to the kernel, or for performing
* in userland file system checking. Needless to say, the kernel makes
* the real checks on calls to get/setacl.
*
* See the comments in kernel for explanation -- just briefly, it assumes
* an already sorted ACL, and checks based on that assumption. The
* POSIX.1e interface, acl_valid(), will perform the sort before calling
* this. Returns 0 on success, EINVAL on failure.
*/
int
_posix1e_acl_check(acl_t acl)
{
struct acl *acl_int;
struct acl_entry *entry; /* current entry */
uid_t highest_uid=0, highest_gid=0;
int stage = ACL_USER_OBJ;
int i = 0;
int count_user_obj=0, count_user=0, count_group_obj=0,
count_group=0, count_mask=0, count_other=0;
acl_int = &acl->ats_acl;
/* printf("_posix1e_acl_check: checking acl with %d entries\n",
acl->acl_cnt); */
while (i < acl_int->acl_cnt) {
entry = &acl_int->acl_entry[i];
if ((entry->ae_perm | ACL_PERM_BITS) != ACL_PERM_BITS)
return (EINVAL);
switch(entry->ae_tag) {
case ACL_USER_OBJ:
/* printf("_posix1e_acl_check: %d: ACL_USER_OBJ\n",
i); */
if (stage > ACL_USER_OBJ)
return (EINVAL);
stage = ACL_USER;
count_user_obj++;
break;
case ACL_USER:
/* printf("_posix1e_acl_check: %d: ACL_USER\n", i); */
if (stage > ACL_USER)
return (EINVAL);
stage = ACL_USER;
if (count_user && (entry->ae_id <= highest_uid))
return (EINVAL);
highest_uid = entry->ae_id;
count_user++;
break;
case ACL_GROUP_OBJ:
/* printf("_posix1e_acl_check: %d: ACL_GROUP_OBJ\n",
i); */
if (stage > ACL_GROUP_OBJ)
return (EINVAL);
stage = ACL_GROUP;
count_group_obj++;
break;
case ACL_GROUP:
/* printf("_posix1e_acl_check: %d: ACL_GROUP\n", i); */
if (stage > ACL_GROUP)
return (EINVAL);
stage = ACL_GROUP;
if (count_group && (entry->ae_id <= highest_gid))
return (EINVAL);
highest_gid = entry->ae_id;
count_group++;
break;
case ACL_MASK:
/* printf("_posix1e_acl_check: %d: ACL_MASK\n", i); */
if (stage > ACL_MASK)
return (EINVAL);
stage = ACL_MASK;
count_mask++;
break;
case ACL_OTHER:
/* printf("_posix1e_acl_check: %d: ACL_OTHER\n", i); */
if (stage > ACL_OTHER)
return (EINVAL);
stage = ACL_OTHER;
count_other++;
break;
default:
/* printf("_posix1e_acl_check: %d: INVALID\n", i); */
return (EINVAL);
}
i++;
}
if (count_user_obj != 1)
return (EINVAL);
if (count_group_obj != 1)
return (EINVAL);
if (count_mask != 0 && count_mask != 1)
return (EINVAL);
if (count_other != 1)
return (EINVAL);
return (0);
}
/*
* Given a right-shifted permission (i.e., direct ACL_PERM_* mask), fill
* in a string describing the permissions.
*/
int
_posix1e_acl_perm_to_string(acl_perm_t perm, ssize_t buf_len, char *buf)
{
if (buf_len < _POSIX1E_ACL_STRING_PERM_MAXSIZE + 1) {
errno = ENOMEM;
return (-1);
}
if ((perm | ACL_PERM_BITS) != ACL_PERM_BITS) {
errno = EINVAL;
return (-1);
}
buf[3] = 0; /* null terminate */
if (perm & ACL_READ)
buf[0] = ACL_STRING_PERM_READ;
else
buf[0] = ACL_STRING_PERM_NONE;
if (perm & ACL_WRITE)
buf[1] = ACL_STRING_PERM_WRITE;
else
buf[1] = ACL_STRING_PERM_NONE;
if (perm & ACL_EXECUTE)
buf[2] = ACL_STRING_PERM_EXEC;
else
buf[2] = ACL_STRING_PERM_NONE;
return (0);
}
/*
* given a string, return a permission describing it
*/
int
_posix1e_acl_string_to_perm(char *string, acl_perm_t *perm)
{
acl_perm_t myperm = ACL_PERM_NONE;
char *ch;
ch = string;
while (*ch) {
switch(*ch) {
case ACL_STRING_PERM_READ:
myperm |= ACL_READ;
break;
case ACL_STRING_PERM_WRITE:
myperm |= ACL_WRITE;
break;
case ACL_STRING_PERM_EXEC:
myperm |= ACL_EXECUTE;
break;
case ACL_STRING_PERM_NONE:
break;
default:
return (EINVAL);
}
ch++;
}
*perm = myperm;
return (0);
}
/*
* Add an ACL entry without doing much checking, et al
*/
int
_posix1e_acl_add_entry(acl_t acl, acl_tag_t tag, uid_t id, acl_perm_t perm)
{
struct acl *acl_int;
struct acl_entry *e;
acl_int = &acl->ats_acl;
if (acl_int->acl_cnt >= ACL_MAX_ENTRIES) {
errno = ENOMEM;
return (-1);
}
e = &(acl_int->acl_entry[acl_int->acl_cnt]);
e->ae_perm = perm;
e->ae_tag = tag;
e->ae_id = id;
acl_int->acl_cnt++;
return (0);
}
/*
* Convert "old" type - ACL_TYPE_{ACCESS,DEFAULT}_OLD - into its "new"
* counterpart. It's necessary for the old (pre-NFSv4 ACLs) binaries
* to work with new libc and kernel. Fixing 'type' for old binaries with
* old libc and new kernel is being done by kern/vfs_acl.c:type_unold().
*/
int
_acl_type_unold(acl_type_t type)
{
switch (type) {
case ACL_TYPE_ACCESS_OLD:
return (ACL_TYPE_ACCESS);
case ACL_TYPE_DEFAULT_OLD:
return (ACL_TYPE_DEFAULT);
default:
return (type);
}
}
char *
string_skip_whitespace(char *string)
{
while (*string && ((*string == ' ') || (*string == '\t')))
string++;
return (string);
}
void
string_trim_trailing_whitespace(char *string)
{
char *end;
if (*string == '\0')
return;
end = string + strlen(string) - 1;
while (end != string) {
if ((*end == ' ') || (*end == '\t')) {
*end = '\0';
end--;
} else {
return;
}
}
return;
}