FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_ipc.c
1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (c) 1994 Herb Peyerl <hpeyerl@novatel.ca>
5 * Copyright (c) 2006 nCircle Network Security, Inc.
6 * All rights reserved.
7 *
8 * This software was developed by Robert N. M. Watson for the TrustedBSD
9 * Project under contract to nCircle Network Security, Inc.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by Herb Peyerl.
22 * 4. The name of Herb Peyerl may not be used to endorse or promote products
23 * derived from this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 *
36 * $NetBSD: sysv_ipc.c,v 1.9 1995/06/02 19:04:22 mycroft Exp $
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
42 #include "opt_sysvipc.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/sem.h>
47 #include <sys/shm.h>
48 #include <sys/ipc.h>
49 #include <sys/priv.h>
50 #include <sys/proc.h>
51 #include <sys/ucred.h>
52
53 #ifndef SYSVSHM
54 void (*shmfork_hook)(struct proc *, struct proc *) = NULL;
55 void (*shmexit_hook)(struct vmspace *) = NULL;
56
57 /* called from kern_fork.c */
58 void
59 shmfork(p1, p2)
60 struct proc *p1, *p2;
61 {
62
63 if (shmfork_hook != NULL)
64 shmfork_hook(p1, p2);
65 return;
66 }
67
68 /* called from kern_exit.c */
69 void
70 shmexit(struct vmspace *vm)
71 {
72
73 if (shmexit_hook != NULL)
74 shmexit_hook(vm);
75 return;
76 }
77 #endif
78
79 /*
80 * Check for IPC permission.
81 *
82 * Note: The MAC Framework does not require any modifications to the
83 * ipcperm() function, as access control checks are performed throughout the
84 * implementation of each primitive. Those entry point calls complement the
85 * ipcperm() discertionary checks. Unlike file system discretionary access
86 * control, the original create of an object is given the same rights as the
87 * current owner.
88 */
89 int
90 ipcperm(struct thread *td, struct ipc_perm *perm, int acc_mode)
91 {
92 struct ucred *cred = td->td_ucred;
93 int error, obj_mode, dac_granted, priv_granted;
94
95 dac_granted = 0;
96 if (cred->cr_uid == perm->cuid || cred->cr_uid == perm->uid) {
97 obj_mode = perm->mode;
98 dac_granted |= IPC_M;
99 } else if (groupmember(perm->gid, cred) ||
100 groupmember(perm->cgid, cred)) {
101 obj_mode = perm->mode;
102 obj_mode <<= 3;
103 } else {
104 obj_mode = perm->mode;
105 obj_mode <<= 6;
106 }
107
108 /*
109 * While the System V IPC permission model allows IPC_M to be
110 * granted, as part of the mode, our implementation requires
111 * privilege to adminster the object if not the owner or creator.
112 */
113 #if 0
114 if (obj_mode & IPC_M)
115 dac_granted |= IPC_M;
116 #endif
117 if (obj_mode & IPC_R)
118 dac_granted |= IPC_R;
119 if (obj_mode & IPC_W)
120 dac_granted |= IPC_W;
121
122 /*
123 * Simple case: all required rights are granted by DAC.
124 */
125 if ((dac_granted & acc_mode) == acc_mode)
126 return (0);
127
128 /*
129 * Privilege is required to satisfy the request.
130 */
131 priv_granted = 0;
132 if ((acc_mode & IPC_M) && !(dac_granted & IPC_M)) {
133 error = priv_check(td, PRIV_IPC_ADMIN);
134 if (error == 0)
135 priv_granted |= IPC_M;
136 }
137
138 if ((acc_mode & IPC_R) && !(dac_granted & IPC_R)) {
139 error = priv_check(td, PRIV_IPC_READ);
140 if (error == 0)
141 priv_granted |= IPC_R;
142 }
143
144 if ((acc_mode & IPC_W) && !(dac_granted & IPC_W)) {
145 error = priv_check(td, PRIV_IPC_WRITE);
146 if (error == 0)
147 priv_granted |= IPC_W;
148 }
149
150 if (((dac_granted | priv_granted) & acc_mode) == acc_mode)
151 return (0);
152 else
153 return (EACCES);
154 }
155
156 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
157 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
158 void
159 ipcperm_old2new(struct ipc_perm_old *old, struct ipc_perm *new)
160 {
161
162 new->cuid = old->cuid;
163 new->cgid = old->cgid;
164 new->uid = old->uid;
165 new->gid = old->gid;
166 new->mode = old->mode;
167 new->seq = old->seq;
168 new->key = old->key;
169 }
170
171 void
172 ipcperm_new2old(struct ipc_perm *new, struct ipc_perm_old *old)
173 {
174
175 /* XXX: How to handle ID's > USHORT_MAX? */
176 old->cuid = new->cuid;
177 old->cgid = new->cgid;
178 old->uid = new->uid;
179 old->gid = new->gid;
180 old->mode = new->mode;
181 old->seq = new->seq;
182 old->key = new->key;
183 }
184 #endif
185
186 #ifdef COMPAT_FREEBSD32
187 #include <sys/mount.h>
188 #include <sys/socket.h>
189 #include <compat/freebsd32/freebsd32.h>
190 #include <compat/freebsd32/freebsd32_ipc.h>
191 #include <compat/freebsd32/freebsd32_proto.h>
192 #include <compat/freebsd32/freebsd32_signal.h>
193 #include <compat/freebsd32/freebsd32_syscall.h>
194 #include <compat/freebsd32/freebsd32_util.h>
195
196 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
197 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
198 void
199 freebsd32_ipcperm_old_in(struct ipc_perm32_old *ip32, struct ipc_perm *ip)
200 {
201
202 CP(*ip32, *ip, cuid);
203 CP(*ip32, *ip, cgid);
204 CP(*ip32, *ip, uid);
205 CP(*ip32, *ip, gid);
206 CP(*ip32, *ip, mode);
207 CP(*ip32, *ip, seq);
208 CP(*ip32, *ip, key);
209 }
210
211 void
212 freebsd32_ipcperm_old_out(struct ipc_perm *ip, struct ipc_perm32_old *ip32)
213 {
214
215 CP(*ip, *ip32, cuid);
216 CP(*ip, *ip32, cgid);
217 CP(*ip, *ip32, uid);
218 CP(*ip, *ip32, gid);
219 CP(*ip, *ip32, mode);
220 CP(*ip, *ip32, seq);
221 CP(*ip, *ip32, key);
222 }
223 #endif
224
225 void
226 freebsd32_ipcperm_in(struct ipc_perm32 *ip32, struct ipc_perm *ip)
227 {
228
229 CP(*ip32, *ip, cuid);
230 CP(*ip32, *ip, cgid);
231 CP(*ip32, *ip, uid);
232 CP(*ip32, *ip, gid);
233 CP(*ip32, *ip, mode);
234 CP(*ip32, *ip, seq);
235 CP(*ip32, *ip, key);
236 }
237
238 void
239 freebsd32_ipcperm_out(struct ipc_perm *ip, struct ipc_perm32 *ip32)
240 {
241
242 CP(*ip, *ip32, cuid);
243 CP(*ip, *ip32, cgid);
244 CP(*ip, *ip32, uid);
245 CP(*ip, *ip32, gid);
246 CP(*ip, *ip32, mode);
247 CP(*ip, *ip32, seq);
248 CP(*ip, *ip32, key);
249 }
250 #endif
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