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