acl_from_text.c revision 167006 
1/*-
2 * Copyright (c) 1999, 2000, 2001 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 * acl_from_text: Convert a text-form ACL from a string to an acl_t.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/lib/libc/posix1e/acl_from_text.c 167006 2007-02-26 02:07:02Z kientzle $");
32
33#include <sys/types.h>
34#include "namespace.h"
35#include <sys/acl.h>
36#include "un-namespace.h"
37#include <sys/errno.h>
38#include <grp.h>
39#include <pwd.h>
40#include <stdio.h>
41#include <stdlib.h>
42#include <string.h>
43
44#include "acl_support.h"
45
46static int _posix1e_acl_name_to_id(acl_tag_t tag, char *name, uid_t *id);
47static acl_tag_t acl_string_to_tag(char *tag, char *qualifier);
48static char *string_skip_whitespace(char *string);
49static void string_trim_trailing_whitespace(char *string);
50
51static char *
52string_skip_whitespace(char *string)
53{
54
55	while (*string && ((*string == ' ') || (*string == '\t'))) {
56		string++;
57	}
58	return (string);
59}
60
61static void
62string_trim_trailing_whitespace(char *string)
63{
64	char	*end;
65
66	if (*string == '\0')
67		return;
68
69	end = string + strlen(string) - 1;
70
71	while (end != string) {
72		if ((*end == ' ') || (*end == '\t')) {
73			*end = '\0';
74			end--;
75		} else {
76			return;
77		}
78	}
79
80	return;
81}
82
83static acl_tag_t
84acl_string_to_tag(char *tag, char *qualifier)
85{
86
87	if (*qualifier == '\0') {
88		if ((!strcmp(tag, "user")) || (!strcmp(tag, "u"))) {
89			return (ACL_USER_OBJ);
90		} else
91		if ((!strcmp(tag, "group")) || (!strcmp(tag, "g"))) {
92			return (ACL_GROUP_OBJ);
93		} else
94		if ((!strcmp(tag, "mask")) || (!strcmp(tag, "m"))) {
95			return (ACL_MASK);
96		} else
97		if ((!strcmp(tag, "other")) || (!strcmp(tag, "o"))) {
98			return (ACL_OTHER);
99		} else
100			return(-1);
101	} else {
102		if ((!strcmp(tag, "user")) || (!strcmp(tag, "u"))) {
103			return(ACL_USER);
104		} else
105		if ((!strcmp(tag, "group")) || (!strcmp(tag, "g"))) {
106			return(ACL_GROUP);
107		} else
108			return(-1);
109	}
110}
111
112/*
113 * acl_from_text -- Convert a string into an ACL.
114 * Postpone most validity checking until the end and call acl_valid() to do
115 * that.
116 */
117acl_t
118acl_from_text(const char *buf_p)
119{
120	acl_tag_t	 t;
121	acl_perm_t	 p;
122	acl_t		 acl;
123	char		*mybuf_p, *line, *cur, *notcomment, *comment, *entry;
124	char		*tag, *qualifier, *permission;
125	int		 error;
126	uid_t		 id;
127
128	/* Local copy we can mess up. */
129	mybuf_p = strdup(buf_p);
130	if (mybuf_p == NULL)
131		return(NULL);
132
133	acl = acl_init(3);
134	if (acl == NULL) {
135		free(mybuf_p);
136		return(NULL);
137	}
138
139	/* Outer loop: delimit at \n boundaries. */
140	cur = mybuf_p;
141	while ((line = strsep(&cur, "\n"))) {
142		/* Now split the line on the first # to strip out comments. */
143		comment = line;
144		notcomment = strsep(&comment, "#");
145
146		/* Inner loop: delimit at ',' boundaries. */
147		while ((entry = strsep(&notcomment, ","))) {
148			/* Now split into three ':' delimited fields. */
149			tag = strsep(&entry, ":");
150			if (tag == NULL) {
151				errno = EINVAL;
152				goto error_label;
153			}
154			tag = string_skip_whitespace(tag);
155			if ((*tag == '\0') && (!entry)) {
156				/*
157				 * Is an entirely comment line, skip to next
158				 * comma.
159				 */
160				continue;
161			}
162			string_trim_trailing_whitespace(tag);
163
164			qualifier = strsep(&entry, ":");
165			if (qualifier == NULL) {
166				errno = EINVAL;
167				goto error_label;
168			}
169			qualifier = string_skip_whitespace(qualifier);
170			string_trim_trailing_whitespace(qualifier);
171
172			permission = strsep(&entry, ":");
173			if (permission == NULL || entry) {
174				errno = EINVAL;
175				goto error_label;
176			}
177			permission = string_skip_whitespace(permission);
178			string_trim_trailing_whitespace(permission);
179
180			t = acl_string_to_tag(tag, qualifier);
181			if (t == -1) {
182				errno = EINVAL;
183				goto error_label;
184			}
185
186			error = _posix1e_acl_string_to_perm(permission, &p);
187			if (error == -1) {
188				errno = EINVAL;
189				goto error_label;
190			}
191
192			switch(t) {
193			case ACL_USER_OBJ:
194			case ACL_GROUP_OBJ:
195			case ACL_MASK:
196			case ACL_OTHER:
197				if (*qualifier != '\0') {
198					errno = EINVAL;
199					goto error_label;
200				}
201				id = 0;
202				break;
203
204			case ACL_USER:
205			case ACL_GROUP:
206				error = _posix1e_acl_name_to_id(t, qualifier,
207				    &id);
208				if (error == -1)
209					goto error_label;
210				break;
211
212			default:
213				errno = EINVAL;
214				goto error_label;
215			}
216
217			error = _posix1e_acl_add_entry(acl, t, id, p);
218			if (error == -1)
219				goto error_label;
220		}
221	}
222
223#if 0
224	/* XXX Should we only return ACLs valid according to acl_valid? */
225	/* Verify validity of the ACL we read in. */
226	if (acl_valid(acl) == -1) {
227		errno = EINVAL;
228		goto error_label;
229	}
230#endif
231
232	return(acl);
233
234error_label:
235	acl_free(acl);
236	free(mybuf_p);
237	return(NULL);
238}
239
240/*
241 * Given a username/groupname from a text form of an ACL, return the uid/gid
242 * XXX NOT THREAD SAFE, RELIES ON GETPWNAM, GETGRNAM
243 * XXX USES *PW* AND *GR* WHICH ARE STATEFUL AND THEREFORE THIS ROUTINE
244 * MAY HAVE SIDE-EFFECTS
245 *
246 * XXX currently doesn't deal correctly with a numeric uid being passed
247 * instead of a username.  What is correct behavior here?  Check chown.
248 */
249static int
250_posix1e_acl_name_to_id(acl_tag_t tag, char *name, uid_t *id)
251{
252	struct group	*g;
253	struct passwd	*p;
254	unsigned long	l;
255	char 		*endp;
256
257	switch(tag) {
258	case ACL_USER:
259		p = getpwnam(name);
260		if (p == NULL) {
261			l = strtoul(name, &endp, 0);
262			if (*endp != '\0' || l != (unsigned long)(uid_t)l) {
263				errno = EINVAL;
264				return (-1);
265			}
266			*id = (uid_t)l;
267			return (0);
268		}
269		*id = p->pw_uid;
270		return (0);
271
272	case ACL_GROUP:
273		g = getgrnam(name);
274		if (g == NULL) {
275			l = strtoul(name, &endp, 0);
276			if (*endp != '\0' || l != (unsigned long)(gid_t)l) {
277				errno = EINVAL;
278				return (-1);
279			}
280			*id = (gid_t)l;
281			return (0);
282		}
283		*id = g->gr_gid;
284		return (0);
285
286	default:
287		return (EINVAL);
288	}
289}
290