sysv_ipc.c

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/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 1994 Herb Peyerl <hpeyerl@novatel.ca>
 * Copyright (c) 2006 nCircle Network Security, Inc.
 * All rights reserved.
 *
 * This software was developed by Robert N. M. Watson for the TrustedBSD
 * Project under contract to nCircle Network Security, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Herb Peyerl.
 * 4. The name of Herb Peyerl may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $NetBSD: sysv_ipc.c,v 1.9 1995/06/02 19:04:22 mycroft Exp $
 */
 
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
 
#include "opt_sysvipc.h"
 
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/ipc.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/ucred.h>
 
#ifndef SYSVSHM
void (*shmfork_hook)(struct proc *, struct proc *) = NULL;
void (*shmexit_hook)(struct vmspace *) = NULL;
 
/* called from kern_fork.c */
void
shmfork(p1, p2)
        struct proc *p1, *p2;
{
 
        if (shmfork_hook != NULL)
                shmfork_hook(p1, p2);
        return;
}
 
/* called from kern_exit.c */
void
shmexit(struct vmspace *vm)
{
 
        if (shmexit_hook != NULL)
                shmexit_hook(vm);
        return;
}
#endif
 
/*
 * Check for IPC permission.
 *
 * Note: The MAC Framework does not require any modifications to the
 * ipcperm() function, as access control checks are performed throughout the
 * implementation of each primitive.  Those entry point calls complement the
 * ipcperm() discertionary checks.  Unlike file system discretionary access
 * control, the original create of an object is given the same rights as the
 * current owner.
 */
int
ipcperm(struct thread *td, struct ipc_perm *perm, int acc_mode)
{
        struct ucred *cred = td->td_ucred;
        int error, obj_mode, dac_granted, priv_granted;
 
        dac_granted = 0;
        if (cred->cr_uid == perm->cuid || cred->cr_uid == perm->uid) {
                obj_mode = perm->mode;
                dac_granted |= IPC_M;
        } else if (groupmember(perm->gid, cred) ||
            groupmember(perm->cgid, cred)) {
                obj_mode = perm->mode;
                obj_mode <<= 3;
        } else {
                obj_mode = perm->mode;
                obj_mode <<= 6;
        }
 
        /*
         * While the System V IPC permission model allows IPC_M to be
         * granted, as part of the mode, our implementation requires
         * privilege to adminster the object if not the owner or creator.
         */
#if 0
        if (obj_mode & IPC_M)
                dac_granted |= IPC_M;
#endif
        if (obj_mode & IPC_R)
                dac_granted |= IPC_R;
        if (obj_mode & IPC_W)
                dac_granted |= IPC_W;
 
        /*
         * Simple case: all required rights are granted by DAC.
         */
        if ((dac_granted & acc_mode) == acc_mode)
                return (0);
 
        /*
         * Privilege is required to satisfy the request.
         */
        priv_granted = 0;
        if ((acc_mode & IPC_M) && !(dac_granted & IPC_M)) {
                error = priv_check(td, PRIV_IPC_ADMIN);
                if (error == 0)
                        priv_granted |= IPC_M;
        }
 
        if ((acc_mode & IPC_R) && !(dac_granted & IPC_R)) {
                error = priv_check(td, PRIV_IPC_READ);
                if (error == 0)
                        priv_granted |= IPC_R;
        }
 
        if ((acc_mode & IPC_W) && !(dac_granted & IPC_W)) {
                error = priv_check(td, PRIV_IPC_WRITE);
                if (error == 0)
                        priv_granted |= IPC_W;
        }
 
        if (((dac_granted | priv_granted) & acc_mode) == acc_mode)
                return (0);
        else
                return (EACCES);
}
 
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
void
ipcperm_old2new(struct ipc_perm_old *old, struct ipc_perm *new)
{
 
        new->cuid = old->cuid;
        new->cgid = old->cgid;
        new->uid = old->uid;
        new->gid = old->gid;
        new->mode = old->mode;
        new->seq = old->seq;
        new->key = old->key;
}
 
void
ipcperm_new2old(struct ipc_perm *new, struct ipc_perm_old *old)
{
 
        /* XXX: How to handle ID's > USHORT_MAX? */
        old->cuid = new->cuid;
        old->cgid = new->cgid;
        old->uid = new->uid;
        old->gid = new->gid;
        old->mode = new->mode;
        old->seq = new->seq;
        old->key = new->key;
}
#endif
 
#ifdef COMPAT_FREEBSD32
#include <sys/mount.h>
#include <sys/socket.h>
#include <compat/freebsd32/freebsd32.h>
#include <compat/freebsd32/freebsd32_ipc.h>
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_signal.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_util.h>
 
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
    defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
void
freebsd32_ipcperm_old_in(struct ipc_perm_old32 *ip32, struct ipc_perm *ip)
{
 
        CP(*ip32, *ip, cuid);
        CP(*ip32, *ip, cgid);
        CP(*ip32, *ip, uid);
        CP(*ip32, *ip, gid);
        CP(*ip32, *ip, mode);
        CP(*ip32, *ip, seq);
        CP(*ip32, *ip, key);
}
 
void
freebsd32_ipcperm_old_out(struct ipc_perm *ip, struct ipc_perm_old32 *ip32)
{
 
        CP(*ip, *ip32, cuid);
        CP(*ip, *ip32, cgid);
        CP(*ip, *ip32, uid);
        CP(*ip, *ip32, gid);
        CP(*ip, *ip32, mode);
        CP(*ip, *ip32, seq);
        CP(*ip, *ip32, key);
}
#endif
 
void
freebsd32_ipcperm_in(struct ipc_perm32 *ip32, struct ipc_perm *ip)
{
 
        CP(*ip32, *ip, cuid);
        CP(*ip32, *ip, cgid);
        CP(*ip32, *ip, uid);
        CP(*ip32, *ip, gid);
        CP(*ip32, *ip, mode);
        CP(*ip32, *ip, seq);
        CP(*ip32, *ip, key);
}
 
void
freebsd32_ipcperm_out(struct ipc_perm *ip, struct ipc_perm32 *ip32)
{
 
        CP(*ip, *ip32, cuid);
        CP(*ip, *ip32, cgid);
        CP(*ip, *ip32, uid);
        CP(*ip, *ip32, gid);
        CP(*ip, *ip32, mode);
        CP(*ip, *ip32, seq);
        CP(*ip, *ip32, key);
}
#endif