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HardenedBSD/sys/kern/kern_module.c
Ka Ho Ng 034c085601 modules: fix freebsd32_modstat on big endian platforms 
The layout of modspecific_t on both little endian and big endian are as
follows:
|0|1|2|3|4|5|6|7|
+-------+-------+
|uintval|       |
+-------+-------+
|ulongval       |
+-------+-------+

For the following code snippet:
        CP(mod->data, data32, longval);
        CP(mod->data, data32, ulongval);
It only takes care of little endian platforms that it truncates the
highest 32bit automatically. However on big endian platforms it takes
the highest 32bit instead. This eventually returns a garbage syscall
number to the 32bit userland.

Since modspecific_t's usage currently is for the use of syscall modules,
we only initialize modspecific32_t with uintval. Now on both BE and LE
64-bit platforms it always pick up the first 4 bytes.

Sponsored by:	Juniper Networks, Inc.
Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D40814
MFC after:	1 week
2023-07-07 00:22:59 -04:00

573 lines
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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 1997 Doug Rabson
* All rights reserved.
*
* 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 AUTHOR 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 AUTHOR 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>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/reboot.h>
#include <sys/sx.h>
#include <sys/module.h>
#include <sys/linker.h>
static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
struct module {
TAILQ_ENTRY(module) link; /* chain together all modules */
TAILQ_ENTRY(module) flink; /* all modules in a file */
struct linker_file *file; /* file which contains this module */
int refs; /* reference count */
int id; /* unique id number */
char *name; /* module name */
modeventhand_t handler; /* event handler */
void *arg; /* argument for handler */
modspecific_t data; /* module specific data */
};
#define MOD_EVENT(mod, type) (mod)->handler((mod), (type), (mod)->arg)
static TAILQ_HEAD(modulelist, module) modules;
struct sx modules_sx;
static int nextid = 1;
static void module_shutdown(void *, int);
static int
modevent_nop(module_t mod, int what, void *arg)
{
switch(what) {
case MOD_LOAD:
return (0);
case MOD_UNLOAD:
return (EBUSY);
default:
return (EOPNOTSUPP);
}
}
static void
module_init(void *arg)
{
sx_init(&modules_sx, "module subsystem sx lock");
TAILQ_INIT(&modules);
EVENTHANDLER_REGISTER(shutdown_final, module_shutdown, NULL,
SHUTDOWN_PRI_DEFAULT);
}
SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, NULL);
static void
module_shutdown(void *arg1, int arg2)
{
module_t mod;
if (arg2 & RB_NOSYNC)
return;
mtx_lock(&Giant);
MOD_SLOCK;
TAILQ_FOREACH_REVERSE(mod, &modules, modulelist, link)
MOD_EVENT(mod, MOD_SHUTDOWN);
MOD_SUNLOCK;
mtx_unlock(&Giant);
}
void
module_register_init(const void *arg)
{
const moduledata_t *data = (const moduledata_t *)arg;
int error;
module_t mod;
mtx_lock(&Giant);
MOD_SLOCK;
mod = module_lookupbyname(data->name);
if (mod == NULL)
panic("module_register_init: module named %s not found\n",
data->name);
MOD_SUNLOCK;
error = MOD_EVENT(mod, MOD_LOAD);
if (error) {
MOD_EVENT(mod, MOD_UNLOAD);
MOD_XLOCK;
module_release(mod);
MOD_XUNLOCK;
printf("module_register_init: MOD_LOAD (%s, %p, %p) error"
" %d\n", data->name, (void *)data->evhand, data->priv,
error);
} else {
MOD_XLOCK;
if (mod->file) {
/*
* Once a module is successfully loaded, move
* it to the head of the module list for this
* linker file. This resorts the list so that
* when the kernel linker iterates over the
* modules to unload them, it will unload them
* in the reverse order they were loaded.
*/
TAILQ_REMOVE(&mod->file->modules, mod, flink);
TAILQ_INSERT_HEAD(&mod->file->modules, mod, flink);
}
MOD_XUNLOCK;
}
mtx_unlock(&Giant);
}
int
module_register(const moduledata_t *data, linker_file_t container)
{
size_t namelen;
module_t newmod;
MOD_XLOCK;
newmod = module_lookupbyname(data->name);
if (newmod != NULL) {
MOD_XUNLOCK;
printf("%s: cannot register %s from %s; already loaded from %s\n",
__func__, data->name, container->filename, newmod->file->filename);
return (EEXIST);
}
namelen = strlen(data->name) + 1;
newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
newmod->refs = 1;
newmod->id = nextid++;
newmod->name = (char *)(newmod + 1);
strcpy(newmod->name, data->name);
newmod->handler = data->evhand ? data->evhand : modevent_nop;
newmod->arg = data->priv;
bzero(&newmod->data, sizeof(newmod->data));
TAILQ_INSERT_TAIL(&modules, newmod, link);
if (container)
TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
newmod->file = container;
MOD_XUNLOCK;
return (0);
}
void
module_reference(module_t mod)
{
MOD_XLOCK_ASSERT;
MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
mod->refs++;
}
void
module_release(module_t mod)
{
MOD_XLOCK_ASSERT;
if (mod->refs <= 0)
panic("module_release: bad reference count");
MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
mod->refs--;
if (mod->refs == 0) {
TAILQ_REMOVE(&modules, mod, link);
if (mod->file)
TAILQ_REMOVE(&mod->file->modules, mod, flink);
free(mod, M_MODULE);
}
}
module_t
module_lookupbyname(const char *name)
{
module_t mod;
int err;
MOD_LOCK_ASSERT;
TAILQ_FOREACH(mod, &modules, link) {
err = strcmp(mod->name, name);
if (err == 0)
return (mod);
}
return (NULL);
}
module_t
module_lookupbyid(int modid)
{
module_t mod;
MOD_LOCK_ASSERT;
TAILQ_FOREACH(mod, &modules, link)
if (mod->id == modid)
return(mod);
return (NULL);
}
int
module_quiesce(module_t mod)
{
int error;
mtx_lock(&Giant);
error = MOD_EVENT(mod, MOD_QUIESCE);
mtx_unlock(&Giant);
if (error == EOPNOTSUPP || error == EINVAL)
error = 0;
return (error);
}
int
module_unload(module_t mod)
{
int error;
mtx_lock(&Giant);
error = MOD_EVENT(mod, MOD_UNLOAD);
mtx_unlock(&Giant);
return (error);
}
int
module_getid(module_t mod)
{
MOD_LOCK_ASSERT;
return (mod->id);
}
module_t
module_getfnext(module_t mod)
{
MOD_LOCK_ASSERT;
return (TAILQ_NEXT(mod, flink));
}
const char *
module_getname(module_t mod)
{
MOD_LOCK_ASSERT;
return (mod->name);
}
void
module_setspecific(module_t mod, modspecific_t *datap)
{
MOD_XLOCK_ASSERT;
mod->data = *datap;
}
linker_file_t
module_file(module_t mod)
{
return (mod->file);
}
/*
* Syscalls.
*/
int
sys_modnext(struct thread *td, struct modnext_args *uap)
{
module_t mod;
int error = 0;
td->td_retval[0] = -1;
MOD_SLOCK;
if (uap->modid == 0) {
mod = TAILQ_FIRST(&modules);
if (mod)
td->td_retval[0] = mod->id;
else
error = ENOENT;
goto done2;
}
mod = module_lookupbyid(uap->modid);
if (mod == NULL) {
error = ENOENT;
goto done2;
}
if (TAILQ_NEXT(mod, link))
td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
else
td->td_retval[0] = 0;
done2:
MOD_SUNLOCK;
return (error);
}
int
sys_modfnext(struct thread *td, struct modfnext_args *uap)
{
module_t mod;
int error;
td->td_retval[0] = -1;
MOD_SLOCK;
mod = module_lookupbyid(uap->modid);
if (mod == NULL) {
error = ENOENT;
} else {
error = 0;
if (TAILQ_NEXT(mod, flink))
td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
else
td->td_retval[0] = 0;
}
MOD_SUNLOCK;
return (error);
}
struct module_stat_v1 {
int version; /* set to sizeof(struct module_stat) */
char name[MAXMODNAMEV1V2];
int refs;
int id;
};
struct module_stat_v2 {
int version; /* set to sizeof(struct module_stat) */
char name[MAXMODNAMEV1V2];
int refs;
int id;
modspecific_t data;
};
int
sys_modstat(struct thread *td, struct modstat_args *uap)
{
module_t mod;
modspecific_t data;
int error = 0;
int id, namelen, refs, version;
struct module_stat *stat;
struct module_stat_v2 *stat_v2;
char *name;
bool is_v1v2;
MOD_SLOCK;
mod = module_lookupbyid(uap->modid);
if (mod == NULL) {
MOD_SUNLOCK;
return (ENOENT);
}
id = mod->id;
refs = mod->refs;
name = mod->name;
data = mod->data;
MOD_SUNLOCK;
stat = uap->stat;
/*
* Check the version of the user's structure.
*/
if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
return (error);
is_v1v2 = (version == sizeof(struct module_stat_v1) ||
version == sizeof(struct module_stat_v2));
if (!is_v1v2 && version != sizeof(struct module_stat))
return (EINVAL);
namelen = strlen(mod->name) + 1;
if (is_v1v2 && namelen > MAXMODNAMEV1V2)
namelen = MAXMODNAMEV1V2;
else if (namelen > MAXMODNAMEV3)
namelen = MAXMODNAMEV3;
if ((error = copyout(name, &stat->name[0], namelen)) != 0)
return (error);
/* Extending MAXMODNAME gives an offset change for v3. */
if (is_v1v2) {
stat_v2 = (struct module_stat_v2 *)stat;
if ((error = copyout(&refs, &stat_v2->refs, sizeof(int))) != 0)
return (error);
if ((error = copyout(&id, &stat_v2->id, sizeof(int))) != 0)
return (error);
} else {
if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
return (error);
if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
return (error);
}
/*
* >v1 stat includes module data.
*/
if (version == sizeof(struct module_stat_v2)) {
if ((error = copyout(&data, &stat_v2->data,
sizeof(data))) != 0)
return (error);
} else if (version == sizeof(struct module_stat)) {
if ((error = copyout(&data, &stat->data,
sizeof(data))) != 0)
return (error);
}
td->td_retval[0] = 0;
return (error);
}
int
sys_modfind(struct thread *td, struct modfind_args *uap)
{
int error = 0;
char name[MAXMODNAMEV3];
module_t mod;
if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
return (error);
MOD_SLOCK;
mod = module_lookupbyname(name);
if (mod == NULL)
error = ENOENT;
else
td->td_retval[0] = module_getid(mod);
MOD_SUNLOCK;
return (error);
}
MODULE_VERSION(kernel, __FreeBSD_version);
#ifdef COMPAT_FREEBSD32
#include <sys/mount.h>
#include <sys/socket.h>
#include <compat/freebsd32/freebsd32_util.h>
#include <compat/freebsd32/freebsd32.h>
#include <compat/freebsd32/freebsd32_proto.h>
typedef union modspecific32 {
int intval;
uint32_t uintval;
int longval;
uint32_t ulongval;
} modspecific32_t;
struct module_stat32_v2 {
int version;
char name[MAXMODNAMEV1V2];
int refs;
int id;
modspecific32_t data;
};
struct module_stat32 {
int version;
char name[MAXMODNAME];
int refs;
int id;
modspecific32_t data;
};
int
freebsd32_modstat(struct thread *td, struct freebsd32_modstat_args *uap)
{
module_t mod;
modspecific32_t data32;
int error = 0;
int id, namelen, refs, version;
struct module_stat32 *stat32;
struct module_stat32_v2 *stat32_v2;
char *name;
bool is_v1v2;
MOD_SLOCK;
mod = module_lookupbyid(uap->modid);
if (mod == NULL) {
MOD_SUNLOCK;
return (ENOENT);
}
id = mod->id;
refs = mod->refs;
name = mod->name;
_Static_assert(sizeof(data32) == sizeof(data32.uintval),
"bad modspecific32_t size");
CP(mod->data, data32, uintval);
MOD_SUNLOCK;
stat32 = uap->stat;
if ((error = copyin(&stat32->version, &version, sizeof(version))) != 0)
return (error);
is_v1v2 = (version == sizeof(struct module_stat_v1) ||
version == sizeof(struct module_stat32_v2));
if (!is_v1v2 && version != sizeof(struct module_stat32))
return (EINVAL);
namelen = strlen(mod->name) + 1;
if (is_v1v2 && namelen > MAXMODNAMEV1V2)
namelen = MAXMODNAMEV1V2;
else if (namelen > MAXMODNAMEV3)
namelen = MAXMODNAMEV3;
if ((error = copyout(name, &stat32->name[0], namelen)) != 0)
return (error);
/* Extending MAXMODNAME gives an offset change for v3. */
if (is_v1v2) {
stat32_v2 = (struct module_stat32_v2 *)stat32;
if ((error = copyout(&refs, &stat32_v2->refs, sizeof(int))) != 0)
return (error);
if ((error = copyout(&id, &stat32_v2->id, sizeof(int))) != 0)
return (error);
} else {
if ((error = copyout(&refs, &stat32->refs, sizeof(int))) != 0)
return (error);
if ((error = copyout(&id, &stat32->id, sizeof(int))) != 0)
return (error);
}
/*
* >v1 stat includes module data.
*/
if (version == sizeof(struct module_stat32_v2)) {
if ((error = copyout(&data32, &stat32_v2->data,
sizeof(data32))) != 0)
return (error);
} else if (version == sizeof(struct module_stat32)) {
if ((error = copyout(&data32, &stat32->data,
sizeof(data32))) != 0)
return (error);
}
td->td_retval[0] = 0;
return (error);
}
#endif
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