1/* $OpenBSD: groupaccess.c,v 1.16 2015/05/04 06:10:48 djm Exp $ */
2/*
3 * Copyright (c) 2001 Kevin Steves.  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 ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
27
28#include <sys/types.h>
29
30#include <grp.h>
31#include <unistd.h>
32#include <stdarg.h>
33#include <stdlib.h>
34#include <string.h>
35#include <limits.h>
36
37#include "xmalloc.h"
38#include "groupaccess.h"
39#include "match.h"
40#include "log.h"
41
42static int ngroups;
43static char **groups_byname;
44
45/*
46 * Initialize group access list for user with primary (base) and
47 * supplementary groups.  Return the number of groups in the list.
48 */
49int
50ga_init(const char *user, gid_t base)
51{
52	gid_t *groups_bygid;
53	int i, j, retry = 0;
54	struct group *gr;
55
56	if (ngroups > 0)
57		ga_free();
58
59	ngroups = NGROUPS_MAX;
60#if defined(HAVE_SYSCONF) && defined(_SC_NGROUPS_MAX)
61	ngroups = MAX(NGROUPS_MAX, sysconf(_SC_NGROUPS_MAX));
62#endif
63
64	groups_bygid = xcalloc(ngroups, sizeof(*groups_bygid));
65	while (getgrouplist(user, base, groups_bygid, &ngroups) == -1) {
66		if (retry++ > 0)
67			fatal("getgrouplist: groups list too small");
68		groups_bygid = xreallocarray(groups_bygid, ngroups,
69		    sizeof(*groups_bygid));
70	}
71	groups_byname = xcalloc(ngroups, sizeof(*groups_byname));
72
73	for (i = 0, j = 0; i < ngroups; i++)
74		if ((gr = getgrgid(groups_bygid[i])) != NULL)
75			groups_byname[j++] = xstrdup(gr->gr_name);
76	free(groups_bygid);
77	return (ngroups = j);
78}
79
80/*
81 * Return 1 if one of user's groups is contained in groups.
82 * Return 0 otherwise.  Use match_pattern() for string comparison.
83 */
84int
85ga_match(char * const *groups, int n)
86{
87	int i, j;
88
89	for (i = 0; i < ngroups; i++)
90		for (j = 0; j < n; j++)
91			if (match_pattern(groups_byname[i], groups[j]))
92				return 1;
93	return 0;
94}
95
96/*
97 * Return 1 if one of user's groups matches group_pattern list.
98 * Return 0 on negated or no match.
99 */
100int
101ga_match_pattern_list(const char *group_pattern)
102{
103	int i, found = 0;
104
105	for (i = 0; i < ngroups; i++) {
106		switch (match_pattern_list(groups_byname[i], group_pattern, 0)) {
107		case -1:
108			return 0;	/* Negated match wins */
109		case 0:
110			continue;
111		case 1:
112			found = 1;
113		}
114	}
115	return found;
116}
117
118/*
119 * Free memory allocated for group access list.
120 */
121void
122ga_free(void)
123{
124	int i;
125
126	if (ngroups > 0) {
127		for (i = 0; i < ngroups; i++)
128			free(groups_byname[i]);
129		ngroups = 0;
130		free(groups_byname);
131		groups_byname = NULL;
132	}
133}
134