1/*-
2 * Copyright (c) 1999-2001, 2008 Robert N. M. Watson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26/*
27 * Support functionality for the POSIX.1e ACL interface
28 * These calls are intended only to be called within the library.
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD$");
33
34#include <sys/types.h>
35#include "namespace.h"
36#include <sys/acl.h>
37#include "un-namespace.h"
38#include <errno.h>
39#include <grp.h>
40#include <pwd.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <assert.h>
45
46#include "acl_support.h"
47
48#define ACL_STRING_PERM_WRITE   'w'
49#define ACL_STRING_PERM_READ    'r'
50#define ACL_STRING_PERM_EXEC    'x'
51#define ACL_STRING_PERM_NONE    '-'
52
53/*
54 * Return 0, if both ACLs are identical.
55 */
56int
57_acl_differs(const acl_t a, const acl_t b)
58{
59	int i;
60	struct acl_entry *entrya, *entryb;
61
62	assert(_acl_brand(a) == _acl_brand(b));
63	assert(_acl_brand(a) != ACL_BRAND_UNKNOWN);
64	assert(_acl_brand(b) != ACL_BRAND_UNKNOWN);
65
66	if (a->ats_acl.acl_cnt != b->ats_acl.acl_cnt)
67		return (1);
68
69	for (i = 0; i < b->ats_acl.acl_cnt; i++) {
70		entrya = &(a->ats_acl.acl_entry[i]);
71		entryb = &(b->ats_acl.acl_entry[i]);
72
73		if (entrya->ae_tag != entryb->ae_tag ||
74		    entrya->ae_id != entryb->ae_id ||
75		    entrya->ae_perm != entryb->ae_perm ||
76		    entrya->ae_entry_type != entryb->ae_entry_type ||
77		    entrya->ae_flags != entryb->ae_flags)
78			return (1);
79	}
80
81	return (0);
82}
83
84/*
85 * _posix1e_acl_entry_compare -- compare two acl_entry structures to
86 * determine the order they should appear in.  Used by _posix1e_acl_sort to
87 * sort ACL entries into the kernel-desired order -- i.e., the order useful
88 * for evaluation and O(n) validity checking.  Beter to have an O(nlogn) sort
89 * in userland and an O(n) in kernel than to have both in kernel.
90 */
91typedef int (*compare)(const void *, const void *);
92static int
93_posix1e_acl_entry_compare(struct acl_entry *a, struct acl_entry *b)
94{
95
96	assert(_entry_brand(a) == ACL_BRAND_POSIX);
97	assert(_entry_brand(b) == ACL_BRAND_POSIX);
98
99	/*
100	 * First, sort between tags -- conveniently defined in the correct
101	 * order for verification.
102	 */
103	if (a->ae_tag < b->ae_tag)
104		return (-1);
105	if (a->ae_tag > b->ae_tag)
106		return (1);
107
108	/*
109	 * Next compare uids/gids on appropriate types.
110	 */
111
112	if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
113		if (a->ae_id < b->ae_id)
114			return (-1);
115		if (a->ae_id > b->ae_id)
116			return (1);
117
118		/* shouldn't be equal, fall through to the invalid case */
119	}
120
121	/*
122	 * Don't know how to sort multiple entries of the rest--either it's
123	 * a bad entry, or there shouldn't be more than one.  Ignore and the
124	 * validity checker can get it later.
125	 */
126	return (0);
127}
128
129/*
130 * _posix1e_acl_sort -- sort ACL entries in POSIX.1e-formatted ACLs.
131 */
132void
133_posix1e_acl_sort(acl_t acl)
134{
135	struct acl *acl_int;
136
137	acl_int = &acl->ats_acl;
138
139	qsort(&acl_int->acl_entry[0], acl_int->acl_cnt,
140	    sizeof(struct acl_entry), (compare) _posix1e_acl_entry_compare);
141}
142
143/*
144 * acl_posix1e -- in what situations should we acl_sort before submission?
145 * We apply posix1e ACL semantics for any ACL of type ACL_TYPE_ACCESS or
146 * ACL_TYPE_DEFAULT
147 */
148int
149_posix1e_acl(acl_t acl, acl_type_t type)
150{
151
152	if (_acl_brand(acl) != ACL_BRAND_POSIX)
153		return (0);
154
155	return ((type == ACL_TYPE_ACCESS) || (type == ACL_TYPE_DEFAULT));
156}
157
158/*
159 * _posix1e_acl_check -- given an ACL, check its validity.  This is mirrored
160 * from code in sys/kern/kern_acl.c, and if changes are made in one, they
161 * should be made in the other also.  This copy of acl_check is made
162 * available * in userland for the benefit of processes wanting to check ACLs
163 * for validity before submitting them to the kernel, or for performing
164 * in userland file system checking.  Needless to say, the kernel makes
165 * the real checks on calls to get/setacl.
166 *
167 * See the comments in kernel for explanation -- just briefly, it assumes
168 * an already sorted ACL, and checks based on that assumption.  The
169 * POSIX.1e interface, acl_valid(), will perform the sort before calling
170 * this.  Returns 0 on success, EINVAL on failure.
171 */
172int
173_posix1e_acl_check(acl_t acl)
174{
175	struct acl *acl_int;
176	struct acl_entry	*entry; 	/* current entry */
177	uid_t	highest_uid=0, highest_gid=0;
178	int	stage = ACL_USER_OBJ;
179	int	i = 0;
180	int	count_user_obj=0, count_user=0, count_group_obj=0,
181		count_group=0, count_mask=0, count_other=0;
182
183	acl_int = &acl->ats_acl;
184
185	/* printf("_posix1e_acl_check: checking acl with %d entries\n",
186	    acl->acl_cnt); */
187	while (i < acl_int->acl_cnt) {
188		entry = &acl_int->acl_entry[i];
189
190		if ((entry->ae_perm | ACL_PERM_BITS) != ACL_PERM_BITS)
191			return (EINVAL);
192
193		switch(entry->ae_tag) {
194		case ACL_USER_OBJ:
195			/* printf("_posix1e_acl_check: %d: ACL_USER_OBJ\n",
196			    i); */
197			if (stage > ACL_USER_OBJ)
198				return (EINVAL);
199			stage = ACL_USER;
200			count_user_obj++;
201			break;
202
203		case ACL_USER:
204			/* printf("_posix1e_acl_check: %d: ACL_USER\n", i); */
205			if (stage > ACL_USER)
206				return (EINVAL);
207			stage = ACL_USER;
208			if (count_user && (entry->ae_id <= highest_uid))
209				return (EINVAL);
210			highest_uid = entry->ae_id;
211			count_user++;
212			break;
213
214		case ACL_GROUP_OBJ:
215			/* printf("_posix1e_acl_check: %d: ACL_GROUP_OBJ\n",
216			    i); */
217			if (stage > ACL_GROUP_OBJ)
218				return (EINVAL);
219			stage = ACL_GROUP;
220			count_group_obj++;
221			break;
222
223		case ACL_GROUP:
224			/* printf("_posix1e_acl_check: %d: ACL_GROUP\n", i); */
225			if (stage > ACL_GROUP)
226				return (EINVAL);
227			stage = ACL_GROUP;
228			if (count_group && (entry->ae_id <= highest_gid))
229				return (EINVAL);
230			highest_gid = entry->ae_id;
231			count_group++;
232			break;
233
234		case ACL_MASK:
235			/* printf("_posix1e_acl_check: %d: ACL_MASK\n", i); */
236			if (stage > ACL_MASK)
237				return (EINVAL);
238			stage = ACL_MASK;
239			count_mask++;
240			break;
241
242		case ACL_OTHER:
243			/* printf("_posix1e_acl_check: %d: ACL_OTHER\n", i); */
244			if (stage > ACL_OTHER)
245				return (EINVAL);
246			stage = ACL_OTHER;
247			count_other++;
248			break;
249
250		default:
251			/* printf("_posix1e_acl_check: %d: INVALID\n", i); */
252			return (EINVAL);
253		}
254		i++;
255	}
256
257	if (count_user_obj != 1)
258		return (EINVAL);
259
260	if (count_group_obj != 1)
261		return (EINVAL);
262
263	if (count_mask != 0 && count_mask != 1)
264		return (EINVAL);
265
266	if (count_other != 1)
267		return (EINVAL);
268
269	return (0);
270}
271
272/*
273 * Given a right-shifted permission (i.e., direct ACL_PERM_* mask), fill
274 * in a string describing the permissions.
275 */
276int
277_posix1e_acl_perm_to_string(acl_perm_t perm, ssize_t buf_len, char *buf)
278{
279
280	if (buf_len < _POSIX1E_ACL_STRING_PERM_MAXSIZE + 1) {
281		errno = ENOMEM;
282		return (-1);
283	}
284
285	if ((perm | ACL_PERM_BITS) != ACL_PERM_BITS) {
286		errno = EINVAL;
287		return (-1);
288	}
289
290	buf[3] = 0;	/* null terminate */
291
292	if (perm & ACL_READ)
293		buf[0] = ACL_STRING_PERM_READ;
294	else
295		buf[0] = ACL_STRING_PERM_NONE;
296
297	if (perm & ACL_WRITE)
298		buf[1] = ACL_STRING_PERM_WRITE;
299	else
300		buf[1] = ACL_STRING_PERM_NONE;
301
302	if (perm & ACL_EXECUTE)
303		buf[2] = ACL_STRING_PERM_EXEC;
304	else
305		buf[2] = ACL_STRING_PERM_NONE;
306
307	return (0);
308}
309
310/*
311 * given a string, return a permission describing it
312 */
313int
314_posix1e_acl_string_to_perm(char *string, acl_perm_t *perm)
315{
316	acl_perm_t	myperm = ACL_PERM_NONE;
317	char	*ch;
318
319	ch = string;
320	while (*ch) {
321		switch(*ch) {
322		case ACL_STRING_PERM_READ:
323			myperm |= ACL_READ;
324			break;
325		case ACL_STRING_PERM_WRITE:
326			myperm |= ACL_WRITE;
327			break;
328		case ACL_STRING_PERM_EXEC:
329			myperm |= ACL_EXECUTE;
330			break;
331		case ACL_STRING_PERM_NONE:
332			break;
333		default:
334			return (EINVAL);
335		}
336		ch++;
337	}
338
339	*perm = myperm;
340	return (0);
341}
342
343/*
344 * Add an ACL entry without doing much checking, et al
345 */
346int
347_posix1e_acl_add_entry(acl_t acl, acl_tag_t tag, uid_t id, acl_perm_t perm)
348{
349	struct acl		*acl_int;
350	struct acl_entry	*e;
351
352	acl_int = &acl->ats_acl;
353
354	if (acl_int->acl_cnt >= ACL_MAX_ENTRIES) {
355		errno = ENOMEM;
356		return (-1);
357	}
358
359	e = &(acl_int->acl_entry[acl_int->acl_cnt]);
360	e->ae_perm = perm;
361	e->ae_tag = tag;
362	e->ae_id = id;
363	acl_int->acl_cnt++;
364
365	return (0);
366}
367
368/*
369 * Convert "old" type - ACL_TYPE_{ACCESS,DEFAULT}_OLD - into its "new"
370 * counterpart.  It's neccessary for the old (pre-NFSv4 ACLs) binaries
371 * to work with new libc and kernel.  Fixing 'type' for old binaries with
372 * old libc and new kernel is being done by kern/vfs_acl.c:type_unold().
373 */
374int
375_acl_type_unold(acl_type_t type)
376{
377
378	switch (type) {
379	case ACL_TYPE_ACCESS_OLD:
380		return (ACL_TYPE_ACCESS);
381	case ACL_TYPE_DEFAULT_OLD:
382		return (ACL_TYPE_DEFAULT);
383	default:
384		return (type);
385	}
386}
387
388char *
389string_skip_whitespace(char *string)
390{
391
392	while (*string && ((*string == ' ') || (*string == '\t')))
393		string++;
394
395	return (string);
396}
397
398void
399string_trim_trailing_whitespace(char *string)
400{
401	char	*end;
402
403	if (*string == '\0')
404		return;
405
406	end = string + strlen(string) - 1;
407
408	while (end != string) {
409		if ((*end == ' ') || (*end == '\t')) {
410			*end = '\0';
411			end--;
412		} else {
413			return;
414		}
415	}
416
417	return;
418}
419