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