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sysv_ipc.c revision 1.15.16.1 
      1 /*	$NetBSD: sysv_ipc.c,v 1.15.16.1 2005/12/11 10:29:12 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Charles M. Hannum.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 __KERNEL_RCSID(0, "$NetBSD: sysv_ipc.c,v 1.15.16.1 2005/12/11 10:29:12 christos Exp $");
     41 
     42 #include <sys/param.h>
     43 #include <sys/kernel.h>
     44 #include <sys/proc.h>
     45 #include <sys/ipc.h>
     46 #include <sys/systm.h>
     47 #include <sys/mount.h>
     48 #include <sys/vnode.h>
     49 #include <sys/stat.h>
     50 
     51 /*
     52  * Check for ipc permission
     53  */
     54 
     55 int
     56 ipcperm(struct ucred *cred, struct ipc_perm *perm, int mode)
     57 {
     58 	mode_t mask;
     59 
     60 	if (cred->cr_uid == 0)
     61 		return (0);
     62 
     63 	if (mode == IPC_M) {
     64 		if (cred->cr_uid == perm->uid ||
     65 		    cred->cr_uid == perm->cuid)
     66 			return (0);
     67 		return (EPERM);
     68 	}
     69 
     70 	mask = 0;
     71 
     72 	if (cred->cr_uid == perm->uid ||
     73 	    cred->cr_uid == perm->cuid) {
     74 		if (mode & IPC_R)
     75 			mask |= S_IRUSR;
     76 		if (mode & IPC_W)
     77 			mask |= S_IWUSR;
     78 		return ((perm->mode & mask) == mask ? 0 : EACCES);
     79 	}
     80 
     81 	if (cred->cr_gid == perm->gid || groupmember(perm->gid, cred) ||
     82 	    cred->cr_gid == perm->cgid || groupmember(perm->cgid, cred)) {
     83 		if (mode & IPC_R)
     84 			mask |= S_IRGRP;
     85 		if (mode & IPC_W)
     86 			mask |= S_IWGRP;
     87 		return ((perm->mode & mask) == mask ? 0 : EACCES);
     88 	}
     89 
     90 	if (mode & IPC_R)
     91 		mask |= S_IROTH;
     92 	if (mode & IPC_W)
     93 		mask |= S_IWOTH;
     94 	return ((perm->mode & mask) == mask ? 0 : EACCES);
     95 }
     96