NetBSD/sys/kern/sysv_ipc.c

/*	$NetBSD: sysv_ipc.c,v 1.20 2007/02/09 21:55:31 ad Exp $	*/

/*-
 * Copyright (c) 1998, 2007 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum.
 *
 * 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 the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sysv_ipc.c,v 1.20 2007/02/09 21:55:31 ad Exp $");

#include "opt_sysv.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/ipc.h>
#ifdef SYSVMSG
#include <sys/msg.h>
#endif
#ifdef SYSVSEM
#include <sys/sem.h>
#endif
#ifdef SYSVSHM
#include <sys/shm.h>
#endif
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/kauth.h>

/*
 * Check for ipc permission
 */

int
ipcperm(kauth_cred_t cred, struct ipc_perm *perm, int mode)
{
	mode_t mask;
	int ismember = 0;

	if (kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER, NULL) == 0)
		return (0);

	if (mode == IPC_M) {
		if (kauth_cred_geteuid(cred) == perm->uid ||
		    kauth_cred_geteuid(cred) == perm->cuid)
			return (0);
		return (EPERM);
	}

	mask = 0;

	if (kauth_cred_geteuid(cred) == perm->uid ||
	    kauth_cred_geteuid(cred) == perm->cuid) {
		if (mode & IPC_R)
			mask |= S_IRUSR;
		if (mode & IPC_W)
			mask |= S_IWUSR;
		return ((perm->mode & mask) == mask ? 0 : EACCES);
	}

	if (kauth_cred_getegid(cred) == perm->gid ||
	    (kauth_cred_ismember_gid(cred, perm->gid, &ismember) == 0 && ismember) ||
	    kauth_cred_getegid(cred) == perm->cgid ||
	    (kauth_cred_ismember_gid(cred, perm->cgid, &ismember) == 0 && ismember)) {
		if (mode & IPC_R)
			mask |= S_IRGRP;
		if (mode & IPC_W)
			mask |= S_IWGRP;
		return ((perm->mode & mask) == mask ? 0 : EACCES);
	}

	if (mode & IPC_R)
		mask |= S_IROTH;
	if (mode & IPC_W)
		mask |= S_IWOTH;
	return ((perm->mode & mask) == mask ? 0 : EACCES);
}

/*
 * sysctl helper routine for kern.ipc.sysvipc_info subtree.
 */

#define FILL_PERM(src, dst) do { \
	(dst)._key = (src)._key; \
	(dst).uid = (src).uid; \
	(dst).gid = (src).gid; \
	(dst).cuid = (src).cuid; \
	(dst).cgid = (src).cgid; \
	(dst).mode = (src).mode; \
	(dst)._seq = (src)._seq; \
} while (/*CONSTCOND*/ 0);

#define FILL_MSG(src, dst) do { \
	FILL_PERM((src).msg_perm, (dst).msg_perm); \
	(dst).msg_qnum = (src).msg_qnum; \
	(dst).msg_qbytes = (src).msg_qbytes; \
	(dst)._msg_cbytes = (src)._msg_cbytes; \
	(dst).msg_lspid = (src).msg_lspid; \
	(dst).msg_lrpid = (src).msg_lrpid; \
	(dst).msg_stime = (src).msg_stime; \
	(dst).msg_rtime = (src).msg_rtime; \
	(dst).msg_ctime = (src).msg_ctime; \
} while (/*CONSTCOND*/ 0)

#define FILL_SEM(src, dst) do { \
	FILL_PERM((src).sem_perm, (dst).sem_perm); \
	(dst).sem_nsems = (src).sem_nsems; \
	(dst).sem_otime = (src).sem_otime; \
	(dst).sem_ctime = (src).sem_ctime; \
} while (/*CONSTCOND*/ 0)

#define FILL_SHM(src, dst) do { \
	FILL_PERM((src).shm_perm, (dst).shm_perm); \
	(dst).shm_segsz = (src).shm_segsz; \
	(dst).shm_lpid = (src).shm_lpid; \
	(dst).shm_cpid = (src).shm_cpid; \
	(dst).shm_atime = (src).shm_atime; \
	(dst).shm_dtime = (src).shm_dtime; \
	(dst).shm_ctime = (src).shm_ctime; \
	(dst).shm_nattch = (src).shm_nattch; \
} while (/*CONSTCOND*/ 0)

static int
sysctl_kern_sysvipc(SYSCTLFN_ARGS)
{
	void *where = oldp;
	size_t *sizep = oldlenp;
#ifdef SYSVMSG
	struct msg_sysctl_info *msgsi = NULL;
#endif
#ifdef SYSVSEM
	struct sem_sysctl_info *semsi = NULL;
#endif
#ifdef SYSVSHM
	struct shm_sysctl_info *shmsi = NULL;
#endif
	size_t infosize, dssize, tsize, buflen;
	void *bf = NULL;
	char *start;
	int32_t nds;
	int i, error, ret;

	if (namelen != 1)
		return EINVAL;

	start = where;
	buflen = *sizep;

	switch (*name) {
	case KERN_SYSVIPC_MSG_INFO:
#ifdef SYSVMSG
		infosize = sizeof(msgsi->msginfo);
		nds = msginfo.msgmni;
		dssize = sizeof(msgsi->msgids[0]);
		break;
#else
		return EINVAL;
#endif
	case KERN_SYSVIPC_SEM_INFO:
#ifdef SYSVSEM
		infosize = sizeof(semsi->seminfo);
		nds = seminfo.semmni;
		dssize = sizeof(semsi->semids[0]);
		break;
#else
		return EINVAL;
#endif
	case KERN_SYSVIPC_SHM_INFO:
#ifdef SYSVSHM
		infosize = sizeof(shmsi->shminfo);
		nds = shminfo.shmmni;
		dssize = sizeof(shmsi->shmids[0]);
		break;
#else
		return EINVAL;
#endif
	default:
		return EINVAL;
	}
	/*
	 * Round infosize to 64 bit boundary if requesting more than just
	 * the info structure or getting the total data size.
	 */
	if (where == NULL || *sizep > infosize)
		infosize = roundup(infosize, sizeof(quad_t));
	tsize = infosize + nds * dssize;

	/* Return just the total size required. */
	if (where == NULL) {
		*sizep = tsize;
		return 0;
	}

	/* Not enough room for even the info struct. */
	if (buflen < infosize) {
		*sizep = 0;
		return ENOMEM;
	}
	bf = malloc(min(tsize, buflen), M_TEMP, M_WAITOK | M_ZERO);

	switch (*name) {
#ifdef SYSVMSG
	case KERN_SYSVIPC_MSG_INFO:
		msgsi = (struct msg_sysctl_info *)bf;
		msgsi->msginfo = msginfo;
		break;
#endif
#ifdef SYSVSEM
	case KERN_SYSVIPC_SEM_INFO:
		semsi = (struct sem_sysctl_info *)bf;
		semsi->seminfo = seminfo;
		break;
#endif
#ifdef SYSVSHM
	case KERN_SYSVIPC_SHM_INFO:
		shmsi = (struct shm_sysctl_info *)bf;
		shmsi->shminfo = shminfo;
		break;
#endif
	}
	buflen -= infosize;

	ret = 0;
	if (buflen > 0) {
		/* Fill in the IPC data structures.  */
		for (i = 0; i < nds; i++) {
			if (buflen < dssize) {
				ret = ENOMEM;
				break;
			}
			switch (*name) {
#ifdef SYSVMSG
			case KERN_SYSVIPC_MSG_INFO:
				mutex_enter(&msgmutex);
				FILL_MSG(msqs[i].msq_u, msgsi->msgids[i]);
				mutex_exit(&msgmutex);
				break;
#endif
#ifdef SYSVSEM
			case KERN_SYSVIPC_SEM_INFO:
				FILL_SEM(sema[i], semsi->semids[i]);
				break;
#endif
#ifdef SYSVSHM
			case KERN_SYSVIPC_SHM_INFO:
				FILL_SHM(shmsegs[i], shmsi->shmids[i]);
				break;
#endif
			}
			buflen -= dssize;
		}
	}
	*sizep -= buflen;
	error = copyout(bf, start, *sizep);
	/* If copyout succeeded, use return code set earlier. */
	if (error == 0)
		error = ret;
	if (bf)
		free(bf, M_TEMP);
	return error;
}

#undef FILL_PERM
#undef FILL_MSG
#undef FILL_SEM
#undef FILL_SHM

SYSCTL_SETUP(sysctl_ipc_setup, "sysctl kern.ipc subtree setup")
{
	sysctl_createv(clog, 0, NULL, NULL,
		CTLFLAG_PERMANENT,
		CTLTYPE_NODE, "kern", NULL,
		NULL, 0, NULL, 0,
		CTL_KERN, CTL_EOL);

	sysctl_createv(clog, 0, NULL, NULL,
		CTLFLAG_PERMANENT,
		CTLTYPE_NODE, "ipc",
		SYSCTL_DESCR("SysV IPC options"),
		NULL, 0, NULL, 0,
		CTL_KERN, KERN_SYSVIPC, CTL_EOL);

	sysctl_createv(clog, 0, NULL, NULL,
		CTLFLAG_PERMANENT,
		CTLTYPE_STRUCT, "sysvipc_info",
		SYSCTL_DESCR("System V style IPC information"),
		sysctl_kern_sysvipc, 0, NULL, 0,
		CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_INFO, CTL_EOL);
}