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 "opt_sysvipc.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/sem.h>
44 #include <sys/shm.h>
45 #include <sys/ipc.h>
46 #include <sys/priv.h>
47 #include <sys/proc.h>
48 #include <sys/ucred.h>
49
50 #ifndef SYSVSHM
51 void (*shmfork_hook)(struct proc *, struct proc *) = NULL;
52 void (*shmexit_hook)(struct vmspace *) = NULL;
53 void (*shmobjinfo_hook)(struct vm_object *, key_t *key,
54 unsigned short *seq) = NULL;
55
56 /* called from kern_fork.c */
57 void
shmfork(struct proc * p1,struct proc * p2)58 shmfork(struct proc *p1, struct proc *p2)
59 {
60 if (shmfork_hook != NULL)
61 shmfork_hook(p1, p2);
62 }
63
64 /* called from kern_exit.c */
65 void
shmexit(struct vmspace * vm)66 shmexit(struct vmspace *vm)
67 {
68 if (shmexit_hook != NULL)
69 shmexit_hook(vm);
70 }
71
72 void
shmobjinfo(struct vm_object * obj,key_t * key,unsigned short * seq)73 shmobjinfo(struct vm_object *obj, key_t *key, unsigned short *seq)
74 {
75 *key = 0; /* For non-present sysvshm.ko */
76 *seq = 0;
77 if (shmobjinfo_hook != NULL)
78 shmobjinfo_hook(obj, key, seq);
79 }
80 #endif
81
82 /*
83 * Check for IPC permission.
84 *
85 * Note: The MAC Framework does not require any modifications to the
86 * ipcperm() function, as access control checks are performed throughout the
87 * implementation of each primitive. Those entry point calls complement the
88 * ipcperm() discertionary checks. Unlike file system discretionary access
89 * control, the original create of an object is given the same rights as the
90 * current owner.
91 */
92 int
ipcperm(struct thread * td,struct ipc_perm * perm,int acc_mode)93 ipcperm(struct thread *td, struct ipc_perm *perm, int acc_mode)
94 {
95 struct ucred *cred = td->td_ucred;
96 int error, obj_mode, dac_granted, priv_granted;
97
98 dac_granted = 0;
99 if (cred->cr_uid == perm->cuid || cred->cr_uid == perm->uid) {
100 obj_mode = perm->mode;
101 dac_granted |= IPC_M;
102 } else if (groupmember(perm->gid, cred) ||
103 groupmember(perm->cgid, cred)) {
104 obj_mode = perm->mode;
105 obj_mode <<= 3;
106 } else {
107 obj_mode = perm->mode;
108 obj_mode <<= 6;
109 }
110
111 /*
112 * While the System V IPC permission model allows IPC_M to be
113 * granted, as part of the mode, our implementation requires
114 * privilege to adminster the object if not the owner or creator.
115 */
116 #if 0
117 if (obj_mode & IPC_M)
118 dac_granted |= IPC_M;
119 #endif
120 if (obj_mode & IPC_R)
121 dac_granted |= IPC_R;
122 if (obj_mode & IPC_W)
123 dac_granted |= IPC_W;
124
125 /*
126 * Simple case: all required rights are granted by DAC.
127 */
128 if ((dac_granted & acc_mode) == acc_mode)
129 return (0);
130
131 /*
132 * Privilege is required to satisfy the request.
133 */
134 priv_granted = 0;
135 if ((acc_mode & IPC_M) && !(dac_granted & IPC_M)) {
136 error = priv_check(td, PRIV_IPC_ADMIN);
137 if (error == 0)
138 priv_granted |= IPC_M;
139 }
140
141 if ((acc_mode & IPC_R) && !(dac_granted & IPC_R)) {
142 error = priv_check(td, PRIV_IPC_READ);
143 if (error == 0)
144 priv_granted |= IPC_R;
145 }
146
147 if ((acc_mode & IPC_W) && !(dac_granted & IPC_W)) {
148 error = priv_check(td, PRIV_IPC_WRITE);
149 if (error == 0)
150 priv_granted |= IPC_W;
151 }
152
153 if (((dac_granted | priv_granted) & acc_mode) == acc_mode)
154 return (0);
155 else
156 return (EACCES);
157 }
158
159 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
160 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
161 void
ipcperm_old2new(struct ipc_perm_old * old,struct ipc_perm * new)162 ipcperm_old2new(struct ipc_perm_old *old, struct ipc_perm *new)
163 {
164
165 new->cuid = old->cuid;
166 new->cgid = old->cgid;
167 new->uid = old->uid;
168 new->gid = old->gid;
169 new->mode = old->mode;
170 new->seq = old->seq;
171 new->key = old->key;
172 }
173
174 void
ipcperm_new2old(struct ipc_perm * new,struct ipc_perm_old * old)175 ipcperm_new2old(struct ipc_perm *new, struct ipc_perm_old *old)
176 {
177
178 /* XXX: How to handle ID's > USHORT_MAX? */
179 old->cuid = new->cuid;
180 old->cgid = new->cgid;
181 old->uid = new->uid;
182 old->gid = new->gid;
183 old->mode = new->mode;
184 old->seq = new->seq;
185 old->key = new->key;
186 }
187 #endif
188
189 #ifdef COMPAT_FREEBSD32
190 #include <sys/mount.h>
191 #include <sys/socket.h>
192 #include <compat/freebsd32/freebsd32.h>
193 #include <compat/freebsd32/freebsd32_ipc.h>
194 #include <compat/freebsd32/freebsd32_proto.h>
195 #include <compat/freebsd32/freebsd32_signal.h>
196 #include <compat/freebsd32/freebsd32_syscall.h>
197 #include <compat/freebsd32/freebsd32_util.h>
198
199 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
200 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
201 void
freebsd32_ipcperm_old_in(struct ipc_perm_old32 * ip32,struct ipc_perm * ip)202 freebsd32_ipcperm_old_in(struct ipc_perm_old32 *ip32, struct ipc_perm *ip)
203 {
204
205 CP(*ip32, *ip, cuid);
206 CP(*ip32, *ip, cgid);
207 CP(*ip32, *ip, uid);
208 CP(*ip32, *ip, gid);
209 CP(*ip32, *ip, mode);
210 CP(*ip32, *ip, seq);
211 CP(*ip32, *ip, key);
212 }
213
214 void
freebsd32_ipcperm_old_out(struct ipc_perm * ip,struct ipc_perm_old32 * ip32)215 freebsd32_ipcperm_old_out(struct ipc_perm *ip, struct ipc_perm_old32 *ip32)
216 {
217
218 CP(*ip, *ip32, cuid);
219 CP(*ip, *ip32, cgid);
220 CP(*ip, *ip32, uid);
221 CP(*ip, *ip32, gid);
222 CP(*ip, *ip32, mode);
223 CP(*ip, *ip32, seq);
224 CP(*ip, *ip32, key);
225 }
226 #endif
227
228 void
freebsd32_ipcperm_in(struct ipc_perm32 * ip32,struct ipc_perm * ip)229 freebsd32_ipcperm_in(struct ipc_perm32 *ip32, struct ipc_perm *ip)
230 {
231
232 CP(*ip32, *ip, cuid);
233 CP(*ip32, *ip, cgid);
234 CP(*ip32, *ip, uid);
235 CP(*ip32, *ip, gid);
236 CP(*ip32, *ip, mode);
237 CP(*ip32, *ip, seq);
238 CP(*ip32, *ip, key);
239 }
240
241 void
freebsd32_ipcperm_out(struct ipc_perm * ip,struct ipc_perm32 * ip32)242 freebsd32_ipcperm_out(struct ipc_perm *ip, struct ipc_perm32 *ip32)
243 {
244
245 CP(*ip, *ip32, cuid);
246 CP(*ip, *ip32, cgid);
247 CP(*ip, *ip32, uid);
248 CP(*ip, *ip32, gid);
249 CP(*ip, *ip32, mode);
250 CP(*ip, *ip32, seq);
251 CP(*ip, *ip32, key);
252 }
253 #endif
254