FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_ipc.c
1 /* $NetBSD: sysv_ipc.c,v 1.7 1994/06/29 06:33:11 cgd Exp $ */
2 /*-
3 * Copyright (c) 1994 Herb Peyerl <hpeyerl@novatel.ca>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by Herb Peyerl.
17 * 4. The name of Herb Peyerl may not be used to endorse or promote products
18 * derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/5.4/sys/kern/sysv_ipc.c 145335 2005-04-20 19:11:07Z cvs2svn $");
34
35 #include "opt_sysvipc.h"
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sem.h>
40 #include <sys/shm.h>
41 #include <sys/ipc.h>
42 #include <sys/proc.h>
43 #include <sys/ucred.h>
44
45 void (*shmfork_hook)(struct proc *, struct proc *) = NULL;
46 void (*shmexit_hook)(struct vmspace *) = NULL;
47
48 /* called from kern_fork.c */
49 void
50 shmfork(p1, p2)
51 struct proc *p1, *p2;
52 {
53
54 if (shmfork_hook != NULL)
55 shmfork_hook(p1, p2);
56 return;
57 }
58
59 /* called from kern_exit.c */
60 void
61 shmexit(struct vmspace *vm)
62 {
63
64 if (shmexit_hook != NULL)
65 shmexit_hook(vm);
66 return;
67 }
68
69 /*
70 * Check for ipc permission
71 */
72
73 int
74 ipcperm(td, perm, mode)
75 struct thread *td;
76 struct ipc_perm *perm;
77 int mode;
78 {
79 struct ucred *cred = td->td_ucred;
80 int error;
81
82 if (cred->cr_uid != perm->cuid && cred->cr_uid != perm->uid) {
83 /*
84 * For a non-create/owner, we require privilege to
85 * modify the object protections. Note: some other
86 * implementations permit IPC_M to be delegated to
87 * unprivileged non-creator/owner uids/gids.
88 */
89 if (mode & IPC_M) {
90 error = suser(td);
91 if (error)
92 return (error);
93 }
94 /*
95 * Try to match against creator/owner group; if not, fall
96 * back on other.
97 */
98 mode >>= 3;
99 if (!groupmember(perm->gid, cred) &&
100 !groupmember(perm->cgid, cred))
101 mode >>= 3;
102 } else {
103 /*
104 * Always permit the creator/owner to update the object
105 * protections regardless of whether the object mode
106 * permits it.
107 */
108 if (mode & IPC_M)
109 return (0);
110 }
111
112 if ((mode & perm->mode) != mode) {
113 if (suser(td) != 0)
114 return (EACCES);
115 }
116 return (0);
117 }
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