xref: /openssh-portable/groupaccess.c (revision fd10cf02)
1 /* $OpenBSD: groupaccess.c,v 1.17 2019/03/06 22:14:23 dtucker 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 
42 static int ngroups;
43 static 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  */
49 int
ga_init(const char * user,gid_t base)50 ga_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  */
84 int
ga_match(char * const * groups,int n)85 ga_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  */
100 int
ga_match_pattern_list(const char * group_pattern)101 ga_match_pattern_list(const char *group_pattern)
102 {
103 	int i, found = 0;
104 
105 	for (i = 0; i < ngroups; i++) {
106 		switch (match_usergroup_pattern_list(groups_byname[i],
107 		    group_pattern)) {
108 		case -1:
109 			return 0;	/* Negated match wins */
110 		case 0:
111 			continue;
112 		case 1:
113 			found = 1;
114 		}
115 	}
116 	return found;
117 }
118 
119 /*
120  * Free memory allocated for group access list.
121  */
122 void
ga_free(void)123 ga_free(void)
124 {
125 	int i;
126 
127 	if (ngroups > 0) {
128 		for (i = 0; i < ngroups; i++)
129 			free(groups_byname[i]);
130 		ngroups = 0;
131 		free(groups_byname);
132 		groups_byname = NULL;
133 	}
134 }
135