xref: /freebsd/sys/contrib/openzfs/module/os/linux/spl/spl-cred.c (revision ebacd8013fe5f7fdf9f6a5b286f6680dd2891036)
1 /*
2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
3  *  Copyright (C) 2007 The Regents of the University of California.
4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
6  *  UCRL-CODE-235197
7  *
8  *  This file is part of the SPL, Solaris Porting Layer.
9  *
10  *  The SPL is free software; you can redistribute it and/or modify it
11  *  under the terms of the GNU General Public License as published by the
12  *  Free Software Foundation; either version 2 of the License, or (at your
13  *  option) any later version.
14  *
15  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
16  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
17  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
18  *  for more details.
19  *
20  *  You should have received a copy of the GNU General Public License along
21  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
22  *
23  *  Solaris Porting Layer (SPL) Credential Implementation.
24  */
25 
26 #include <sys/cred.h>
27 
28 static int
29 cr_groups_search(const struct group_info *group_info, kgid_t grp)
30 {
31 	unsigned int left, right, mid;
32 	int cmp;
33 
34 	if (!group_info)
35 		return (0);
36 
37 	left = 0;
38 	right = group_info->ngroups;
39 	while (left < right) {
40 		mid = (left + right) / 2;
41 		cmp = KGID_TO_SGID(grp) -
42 		    KGID_TO_SGID(GROUP_AT(group_info, mid));
43 
44 		if (cmp > 0)
45 			left = mid + 1;
46 		else if (cmp < 0)
47 			right = mid;
48 		else
49 			return (1);
50 	}
51 	return (0);
52 }
53 
54 /* Hold a reference on the credential */
55 void
56 crhold(cred_t *cr)
57 {
58 	(void) get_cred((const cred_t *)cr);
59 }
60 
61 /* Free a reference on the credential */
62 void
63 crfree(cred_t *cr)
64 {
65 	put_cred((const cred_t *)cr);
66 }
67 
68 /* Return the number of supplemental groups */
69 int
70 crgetngroups(const cred_t *cr)
71 {
72 	struct group_info *gi;
73 	int rc;
74 
75 	gi = cr->group_info;
76 	rc = gi->ngroups;
77 #ifndef HAVE_GROUP_INFO_GID
78 	/*
79 	 * For Linux <= 4.8,
80 	 * crgetgroups will only returns gi->blocks[0], which contains only
81 	 * the first NGROUPS_PER_BLOCK groups.
82 	 */
83 	if (rc > NGROUPS_PER_BLOCK) {
84 		WARN_ON_ONCE(1);
85 		rc = NGROUPS_PER_BLOCK;
86 	}
87 #endif
88 	return (rc);
89 }
90 
91 /*
92  * Return an array of supplemental gids.  The returned address is safe
93  * to use as long as the caller has taken a reference with crhold().
94  *
95  * Linux 4.9 API change, group_info changed from 2d array via ->blocks to 1d
96  * array via ->gid.
97  */
98 gid_t *
99 crgetgroups(const cred_t *cr)
100 {
101 	struct group_info *gi;
102 	gid_t *gids = NULL;
103 
104 	gi = cr->group_info;
105 #ifdef HAVE_GROUP_INFO_GID
106 	gids = KGIDP_TO_SGIDP(gi->gid);
107 #else
108 	if (gi->nblocks > 0)
109 		gids = KGIDP_TO_SGIDP(gi->blocks[0]);
110 #endif
111 	return (gids);
112 }
113 
114 /* Check if the passed gid is available in supplied credential. */
115 int
116 groupmember(gid_t gid, const cred_t *cr)
117 {
118 	struct group_info *gi;
119 	int rc;
120 
121 	gi = cr->group_info;
122 	rc = cr_groups_search(gi, SGID_TO_KGID(gid));
123 
124 	return (rc);
125 }
126 
127 /* Return the effective user id */
128 uid_t
129 crgetuid(const cred_t *cr)
130 {
131 	return (KUID_TO_SUID(cr->fsuid));
132 }
133 
134 /* Return the real user id */
135 uid_t
136 crgetruid(const cred_t *cr)
137 {
138 	return (KUID_TO_SUID(cr->uid));
139 }
140 
141 /* Return the effective group id */
142 gid_t
143 crgetgid(const cred_t *cr)
144 {
145 	return (KGID_TO_SGID(cr->fsgid));
146 }
147 
148 EXPORT_SYMBOL(crhold);
149 EXPORT_SYMBOL(crfree);
150 EXPORT_SYMBOL(crgetuid);
151 EXPORT_SYMBOL(crgetruid);
152 EXPORT_SYMBOL(crgetgid);
153 EXPORT_SYMBOL(crgetngroups);
154 EXPORT_SYMBOL(crgetgroups);
155 EXPORT_SYMBOL(groupmember);
156