1 /* $NetBSD: creds.c,v 1.16 2012/03/15 12:49:36 njoly Exp $ */
2
3 /*
4 * Copyright (c) 2006 Antti Kantee. All Rights Reserved.
5 *
6 * Development of this software was supported by the Ulla Tuominen Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 #if !defined(lint)
32 __RCSID("$NetBSD: creds.c,v 1.16 2012/03/15 12:49:36 njoly Exp $");
33 #endif /* !lint */
34
35 /*
36 * Interface for dealing with credits.
37 */
38
39 #include <sys/types.h>
40 #include <sys/param.h>
41
42 #include <errno.h>
43 #include <puffs.h>
44 #include <stdbool.h>
45 #include <string.h>
46
47 #include "puffs_priv.h"
48
49 #define UUCCRED(a) (a->pkcr_type == PUFFCRED_TYPE_UUC)
50 #define INTCRED(a) (a->pkcr_type == PUFFCRED_TYPE_INTERNAL)
51
52 int
puffs_cred_getuid(const struct puffs_cred * pcr,uid_t * ruid)53 puffs_cred_getuid(const struct puffs_cred *pcr, uid_t *ruid)
54 {
55 PUFFS_MAKEKCRED(pkcr, pcr);
56
57 if (!UUCCRED(pkcr)) {
58 errno = EOPNOTSUPP;
59 return -1;
60 }
61 *ruid = pkcr->pkcr_uuc.cr_uid;
62
63 return 0;
64 }
65
66 int
puffs_cred_getgid(const struct puffs_cred * pcr,gid_t * rgid)67 puffs_cred_getgid(const struct puffs_cred *pcr, gid_t *rgid)
68 {
69 PUFFS_MAKEKCRED(pkcr, pcr);
70
71 if (!UUCCRED(pkcr)) {
72 errno = EOPNOTSUPP;
73 return -1;
74 }
75 *rgid = pkcr->pkcr_uuc.cr_gid;
76
77 return 0;
78 }
79
80 int
puffs_cred_getgroups(const struct puffs_cred * pcr,gid_t * rgids,short * ngids)81 puffs_cred_getgroups(const struct puffs_cred *pcr, gid_t *rgids, short *ngids)
82 {
83 PUFFS_MAKEKCRED(pkcr, pcr);
84 size_t ncopy;
85
86 if (!UUCCRED(pkcr)) {
87 errno = EOPNOTSUPP;
88 *ngids = 0;
89 return -1;
90 }
91
92 ncopy = MIN(*ngids, pkcr->pkcr_uuc.cr_ngroups);
93 (void)memcpy(rgids, pkcr->pkcr_uuc.cr_groups, sizeof(gid_t) * ncopy);
94 *ngids = (short)ncopy;
95
96 return 0;
97 }
98
99 bool
puffs_cred_isuid(const struct puffs_cred * pcr,uid_t uid)100 puffs_cred_isuid(const struct puffs_cred *pcr, uid_t uid)
101 {
102 PUFFS_MAKEKCRED(pkcr, pcr);
103
104 return UUCCRED(pkcr) && pkcr->pkcr_uuc.cr_uid == uid;
105 }
106
107 bool
puffs_cred_hasgroup(const struct puffs_cred * pcr,gid_t gid)108 puffs_cred_hasgroup(const struct puffs_cred *pcr, gid_t gid)
109 {
110 PUFFS_MAKEKCRED(pkcr, pcr);
111 short i;
112
113 if (!UUCCRED(pkcr))
114 return false;
115
116 if (pkcr->pkcr_uuc.cr_gid == gid)
117 return true;
118 for (i = 0; i < pkcr->pkcr_uuc.cr_ngroups; i++)
119 if (pkcr->pkcr_uuc.cr_groups[i] == gid)
120 return true;
121
122 return false;
123 }
124
125 bool
puffs_cred_isregular(const struct puffs_cred * pcr)126 puffs_cred_isregular(const struct puffs_cred *pcr)
127 {
128 PUFFS_MAKEKCRED(pkcr, pcr);
129
130 return UUCCRED(pkcr);
131 }
132
133 bool
puffs_cred_iskernel(const struct puffs_cred * pcr)134 puffs_cred_iskernel(const struct puffs_cred *pcr)
135 {
136 PUFFS_MAKEKCRED(pkcr, pcr);
137
138 return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_NOCRED;
139 }
140
141 bool
puffs_cred_isfs(const struct puffs_cred * pcr)142 puffs_cred_isfs(const struct puffs_cred *pcr)
143 {
144 PUFFS_MAKEKCRED(pkcr, pcr);
145
146 return INTCRED(pkcr) && pkcr->pkcr_internal == PUFFCRED_CRED_FSCRED;
147 }
148
149 bool
puffs_cred_isjuggernaut(const struct puffs_cred * pcr)150 puffs_cred_isjuggernaut(const struct puffs_cred *pcr)
151 {
152
153 return puffs_cred_isuid(pcr, 0) || puffs_cred_iskernel(pcr)
154 || puffs_cred_isfs(pcr);
155 }
156
157 /*
158 * Generic routine for checking file access rights. Modeled after
159 * vaccess() in the kernel.
160 */
161 int
puffs_access(enum vtype type,mode_t file_mode,uid_t uid,gid_t gid,mode_t acc_mode,const struct puffs_cred * pcr)162 puffs_access(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
163 mode_t acc_mode, const struct puffs_cred *pcr)
164 {
165 mode_t mask;
166
167 /* megapower */
168 if (puffs_cred_iskernel(pcr) || puffs_cred_isfs(pcr))
169 return 0;
170
171 /* superuser, allow all except exec if *ALL* exec bits are unset */
172 if (puffs_cred_isuid(pcr, 0)) {
173 if ((acc_mode & PUFFS_VEXEC) && type != VDIR &&
174 (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
175 return EACCES;
176 return 0;
177 }
178
179 mask = 0;
180 /* owner */
181 if (puffs_cred_isuid(pcr, uid)) {
182 if (acc_mode & PUFFS_VEXEC)
183 mask |= S_IXUSR;
184 if (acc_mode & PUFFS_VREAD)
185 mask |= S_IRUSR;
186 if (acc_mode & PUFFS_VWRITE)
187 mask |= S_IWUSR;
188 /* group */
189 } else if (puffs_cred_hasgroup(pcr, gid)) {
190 if (acc_mode & PUFFS_VEXEC)
191 mask |= S_IXGRP;
192 if (acc_mode & PUFFS_VREAD)
193 mask |= S_IRGRP;
194 if (acc_mode & PUFFS_VWRITE)
195 mask |= S_IWGRP;
196 /* other */
197 } else {
198 if (acc_mode & PUFFS_VEXEC)
199 mask |= S_IXOTH;
200 if (acc_mode & PUFFS_VREAD)
201 mask |= S_IROTH;
202 if (acc_mode & PUFFS_VWRITE)
203 mask |= S_IWOTH;
204 }
205
206 if ((file_mode & mask) == mask)
207 return 0;
208 else
209 return EACCES;
210 }
211
212 int
puffs_access_chown(uid_t owner,gid_t group,uid_t newowner,gid_t newgroup,const struct puffs_cred * pcr)213 puffs_access_chown(uid_t owner, gid_t group, uid_t newowner, gid_t newgroup,
214 const struct puffs_cred *pcr)
215 {
216
217 if (newowner == (uid_t)PUFFS_VNOVAL)
218 newowner = owner;
219 if (newgroup == (gid_t)PUFFS_VNOVAL)
220 newgroup = group;
221
222 if ((!puffs_cred_isuid(pcr, owner) || newowner != owner ||
223 ((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
224 && !puffs_cred_isjuggernaut(pcr))
225 return EPERM;
226
227 return 0;
228 }
229
230 int
puffs_access_chmod(uid_t owner,gid_t group,enum vtype type,mode_t mode,const struct puffs_cred * pcr)231 puffs_access_chmod(uid_t owner, gid_t group, enum vtype type, mode_t mode,
232 const struct puffs_cred *pcr)
233 {
234
235 if (!puffs_cred_isuid(pcr, owner) && !puffs_cred_isjuggernaut(pcr))
236 return EPERM;
237
238 if (!puffs_cred_isjuggernaut(pcr)) {
239 if (type != VDIR && (mode & S_ISTXT))
240 return EFTYPE;
241 if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
242 return EPERM;
243 }
244
245 return 0;
246 }
247
248 int
puffs_access_times(uid_t uid,gid_t gid,mode_t mode,int va_utimes_null,const struct puffs_cred * pcr)249 puffs_access_times(uid_t uid, gid_t gid, mode_t mode, int va_utimes_null,
250 const struct puffs_cred *pcr)
251 {
252
253 if (puffs_cred_isuid(pcr, uid) || puffs_cred_isjuggernaut(pcr))
254 return 0;
255
256 if (va_utimes_null == 0)
257 return EPERM;
258
259 return puffs_access(VNON, mode, uid, gid, PUFFS_VWRITE, pcr);
260 }
261