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NetBSD/sys/kern/sysv_ipc.c
pgoyette 97b627eca5 Many years ago someone created a new __link_set_sysctl_funcs to hold 
the list of routines that need to be called for setting up sysctl
variables.  This worked great for all code included in the kernel
itself, but didn't deal with modules that want to create their own
sysctl data.  So, we ended up with a lot of #ifdef _MODULE blocks
so modules could explicitly call their setup functions when loaded
as non-built-in modules.

So today, we complete the task that was started so many years ago.

When modules are loaded, after we've called xxx_modcmd(INIT...) we
check if the module contains its own __link_set_sysctl_funcs, and
if so we call the functions listed.  We add a struct sysctllog member
to the struct module so we can call sysctl_teardown() when the module
gets unloaded.  (The sequence of events ensures that the sysctl stuff
doesn't get created until the rest of the module's init code does any
required memory allocation.)

So, no more need to explicitly call the sysctl setup routines when
built as a loadable module.
2019-08-07 00:38:01 +00:00

526 lines
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/* $NetBSD: sysv_ipc.c,v 1.40 2019/08/07 00:38:02 pgoyette 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.
*
* 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 1.40 2019/08/07 00:38:02 pgoyette Exp $");
#ifdef _KERNEL_OPT
#include "opt_sysv.h"
#include "opt_sysvparam.h"
#include "opt_compat_netbsd.h"
#endif
#include <sys/syscall.h>
#include <sys/syscallargs.h>
#include <sys/syscallvar.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/kmem.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/kauth.h>
#include <sys/compat_stub.h>
#include <compat/common/compat_sysv_mod.h> /* for sysctl routine vector */
/*
* Values in support of System V compatible shared memory. XXX
* (originally located in sys/conf/param.c)
*/
#ifdef SYSVSHM
#if !defined(SHMMAX) && defined(SHMMAXPGS)
#define SHMMAX SHMMAXPGS /* shminit() performs a `*= PAGE_SIZE' */
#elif !defined(SHMMAX)
#define SHMMAX 0
#endif
#ifndef SHMMIN
#define SHMMIN 1
#endif
#ifndef SHMMNI
#define SHMMNI 128 /* <64k, see IPCID_TO_IX in ipc.h */
#endif
#ifndef SHMSEG
#define SHMSEG 128
#endif
struct shminfo shminfo = {
SHMMAX,
SHMMIN,
SHMMNI,
SHMSEG,
0
};
#endif
/*
* Values in support of System V compatible semaphores.
*/
#ifdef SYSVSEM
struct seminfo seminfo = {
SEMMAP, /* # of entries in semaphore map */
SEMMNI, /* # of semaphore identifiers */
SEMMNS, /* # of semaphores in system */
SEMMNU, /* # of undo structures in system */
SEMMSL, /* max # of semaphores per id */
SEMOPM, /* max # of operations per semop call */
SEMUME, /* max # of undo entries per process */
SEMUSZ, /* size in bytes of undo structure */
SEMVMX, /* semaphore maximum value */
SEMAEM /* adjust on exit max value */
};
#endif
/*
* Values in support of System V compatible messages.
*/
#ifdef SYSVMSG
struct msginfo msginfo = {
MSGMAX, /* max chars in a message */
MSGMNI, /* # of message queue identifiers */
MSGMNB, /* max chars in a queue */
MSGTQL, /* max messages in system */
MSGSSZ, /* size of a message segment */
/* (must be small power of 2 greater than 4) */
MSGSEG /* number of message segments */
};
#endif
MODULE(MODULE_CLASS_EXEC, sysv_ipc, NULL);
SYSCTL_SETUP_PROTO(sysctl_ipc_setup);
static const struct syscall_package sysvipc_syscalls[] = {
#if defined(SYSVSHM)
{ SYS___shmctl50, 0, (sy_call_t *)sys___shmctl50 },
{ SYS_shmat, 0, (sy_call_t *)sys_shmat },
{ SYS_shmdt, 0, (sy_call_t *)sys_shmdt },
{ SYS_shmget, 0, (sy_call_t *)sys_shmget },
#endif /* SYSVSHM */
#if defined(SYSVSEM)
{ SYS_____semctl50, 0, (sy_call_t *)sys_____semctl50 },
{ SYS_semget, 0, (sy_call_t *)sys_semget },
{ SYS_semop, 0, (sy_call_t *)sys_semop },
{ SYS_semconfig, 0, (sy_call_t *)sys_semconfig },
#endif /* SYSVSEM */
#if defined(SYSVMSG)
{ SYS___msgctl50, 0, (sy_call_t *)sys___msgctl50 },
{ SYS_msgget, 0, (sy_call_t *)sys_msgget },
{ SYS_msgsnd, 0, (sy_call_t *)sys_msgsnd },
{ SYS_msgrcv, 0, (sy_call_t *)sys_msgrcv },
#endif /* SYSVMSG */
{ 0, 0, NULL }
};
static int
sysv_ipc_modcmd(modcmd_t cmd, void *arg)
{
int error = 0;
switch (cmd) {
case MODULE_CMD_INIT:
/* Set up the kauth listener */
sysvipcinit();
/* Link the system calls */
error = syscall_establish(NULL, sysvipc_syscalls);
if (error) {
sysvipcfini();
return error;
}
/*
* Initialize each sub-component, including their
* sysctl data
*/
#ifdef SYSVSHM
error = shminit();
if (error != 0)
return error;
#endif
#ifdef SYSVSEM
error = seminit();
if (error != 0) {
#ifdef SYSVSHM
shmfini();
#endif
return error;
}
#endif
#ifdef SYSVMSG
error = msginit();
if (error != 0) {
#ifdef SYSVSEM
semfini();
#endif
#ifdef SYSVSHM
shmfini();
#endif
return error;
}
#endif
break;
case MODULE_CMD_FINI:
/*
* Make sure no subcomponents are active. Each one
* tells us if it is busy, and if it was _not_ busy,
* we assume it has already done its own clean-up.
* So we might need to re-init any components that
* are successfully fini'd if we find one that is
* still busy.
*/
#ifdef SYSVSHM
if (shmfini()) {
return EBUSY;
}
#endif
#ifdef SYSVSEM
if (semfini()) {
#ifdef SYSVSHM
shminit();
#endif
return EBUSY;
}
#endif
#ifdef SYSVMSG
if (msgfini()) {
#ifdef SYSVSEM
seminit();
#endif
#ifdef SYSVSHM
shminit();
#endif
return EBUSY;
}
#endif
/* Unlink the system calls. */
error = syscall_disestablish(NULL, sysvipc_syscalls);
if (error)
return error;
/* Remove the kauth listener */
sysvipcfini();
break;
default:
return ENOTTY;
}
return error;
}
static kauth_listener_t sysvipc_listener = NULL;
static int
sysvipc_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
void *arg0, void *arg1, void *arg2, void *arg3)
{
mode_t mask;
int ismember = 0;
struct ipc_perm *perm;
int mode;
enum kauth_system_req req;
req = (enum kauth_system_req)arg0;
if (!(action == KAUTH_SYSTEM_SYSVIPC &&
req == KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS))
return KAUTH_RESULT_DEFER;
perm = arg1;
mode = (int)(uintptr_t)arg2;
if (mode == IPC_M) {
if (kauth_cred_geteuid(cred) == perm->uid ||
kauth_cred_geteuid(cred) == perm->cuid)
return (KAUTH_RESULT_ALLOW);
return (KAUTH_RESULT_DEFER); /* 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 ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* 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 ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */);
}
if (mode & IPC_R)
mask |= S_IROTH;
if (mode & IPC_W)
mask |= S_IWOTH;
return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */);
}
/*
* Check for ipc permission
*/
int
ipcperm(kauth_cred_t cred, struct ipc_perm *perm, int mode)
{
int error;
error = kauth_authorize_system(cred, KAUTH_SYSTEM_SYSVIPC,
KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS, perm, KAUTH_ARG(mode), NULL);
if (error == 0)
return (0);
/* Adjust EPERM and EACCES errors until there's a better way to do this. */
if (mode != IPC_M)
error = EACCES;
return error;
}
void
sysvipcfini(void)
{
KASSERT(sysvipc_listener != NULL);
kauth_unlisten_scope(sysvipc_listener);
sysvipc_listener = NULL;
}
void
sysvipcinit(void)
{
KASSERT(sysvipc_listener == NULL);
sysvipc_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM,
sysvipc_listener_cb, NULL);
}
static int
stub_sysvipc50_sysctl(SYSCTLFN_ARGS)
{
return EPASSTHROUGH;
}
static int
sysctl_kern_sysvipc(SYSCTLFN_ARGS)
{
void *where = oldp;
size_t sz, *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 present, call the compat sysctl() code. If it handles the request
* completely (either success or error), return. Otherwise fallthrough
* to the non-compat sysctl code.
*/
MODULE_HOOK_CALL(sysvipc_sysctl_50_hook, (SYSCTLFN_CALL(rnode)),
stub_sysvipc50_sysctl(SYSCTLFN_CALL(rnode)), error);
if (error != EPASSTHROUGH)
return error;
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;
}
sz = uimin(tsize, buflen);
bf = kmem_zalloc(sz, KM_SLEEP);
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);
SYSCTL_FILL_MSG(msqs[i].msq_u, msgsi->msgids[i]);
mutex_exit(&msgmutex);
break;
#endif
#ifdef SYSVSEM
case KERN_SYSVIPC_SEM_INFO:
SYSCTL_FILL_SEM(sema[i], semsi->semids[i]);
break;
#endif
#ifdef SYSVSHM
case KERN_SYSVIPC_SHM_INFO:
SYSCTL_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)
kmem_free(bf, sz);
return error;
}
SYSCTL_SETUP(sysctl_ipc_setup, "sysctl kern.ipc subtree setup")
{
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);
}
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