freebsd-dev/sys/cddl/dev/systrace/systrace.c
Mark Johnston 36f5d07745 Re-check the systrace probe ID before calling dtrace_probe().
Otherwise there exists a narrow window during which a syscall probe can be
disabled and cause a concurrently-running thread to call dtrace_probe()
with an invalid probe ID.

Reported by:	ngie
MFC after:	1 week
Sponsored by:	Dell EMC Isilon
2016-09-22 23:22:53 +00:00

410 lines
11 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* Portions Copyright 2006-2008 John Birrell jb@freebsd.org
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/cpuvar.h>
#include <sys/dtrace.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/kthread.h>
#include <sys/limits.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/selinfo.h>
#include <sys/smp.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/uio.h>
#include <sys/unistd.h>
#include <cddl/dev/dtrace/dtrace_cddl.h>
#include <machine/stdarg.h>
#ifdef LINUX_SYSTRACE
#if defined(__amd64__)
#include <amd64/linux/linux.h>
#include <amd64/linux/linux_proto.h>
#include <amd64/linux/linux_syscalls.c>
#include <amd64/linux/linux_systrace_args.c>
#elif defined(__i386__)
#include <i386/linux/linux.h>
#include <i386/linux/linux_proto.h>
#include <i386/linux/linux_syscalls.c>
#include <i386/linux/linux_systrace_args.c>
#else
#error Only i386 and amd64 are supported.
#endif
#define MODNAME "linux"
extern struct sysent linux_sysent[];
#define MAXSYSCALL LINUX_SYS_MAXSYSCALL
#define SYSCALLNAMES linux_syscallnames
#define SYSENT linux_sysent
#elif defined(LINUX32_SYSTRACE)
#if defined(__amd64__)
#include <amd64/linux32/linux.h>
#include <amd64/linux32/linux32_proto.h>
#include <amd64/linux32/linux32_syscalls.c>
#include <amd64/linux32/linux32_systrace_args.c>
#else
#error Only amd64 is supported.
#endif
#define MODNAME "linux32"
extern struct sysent linux32_sysent[];
#define MAXSYSCALL LINUX32_SYS_MAXSYSCALL
#define SYSCALLNAMES linux32_syscallnames
#define SYSENT linux32_sysent
#elif defined(FREEBSD32_SYSTRACE)
/*
* The syscall arguments are processed into a DTrace argument array
* using a generated function. See sys/kern/makesyscalls.sh.
*/
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_util.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_systrace_args.c>
extern const char *freebsd32_syscallnames[];
#define MODNAME "freebsd32"
#define MAXSYSCALL FREEBSD32_SYS_MAXSYSCALL
#define SYSCALLNAMES freebsd32_syscallnames
#define SYSENT freebsd32_sysent
#else
/*
* The syscall arguments are processed into a DTrace argument array
* using a generated function. See sys/kern/makesyscalls.sh.
*/
#include <sys/syscall.h>
#include <kern/systrace_args.c>
#define MODNAME "freebsd"
#define MAXSYSCALL SYS_MAXSYSCALL
#define SYSCALLNAMES syscallnames
#define SYSENT sysent
#define NATIVE_ABI
#endif
#define PROVNAME "syscall"
#define DEVNAME "dtrace/systrace/" MODNAME
#define SYSTRACE_ARTIFICIAL_FRAMES 1
#define SYSTRACE_SHIFT 16
#define SYSTRACE_ISENTRY(x) ((int)(x) >> SYSTRACE_SHIFT)
#define SYSTRACE_SYSNUM(x) ((int)(x) & ((1 << SYSTRACE_SHIFT) - 1))
#define SYSTRACE_ENTRY(id) ((1 << SYSTRACE_SHIFT) | (id))
#define SYSTRACE_RETURN(id) (id)
#if ((1 << SYSTRACE_SHIFT) <= MAXSYSCALL)
#error 1 << SYSTRACE_SHIFT must exceed number of system calls
#endif
static void systrace_load(void *);
static void systrace_unload(void *);
static void systrace_getargdesc(void *, dtrace_id_t, void *,
dtrace_argdesc_t *);
static uint64_t systrace_getargval(void *, dtrace_id_t, void *, int, int);
static void systrace_provide(void *, dtrace_probedesc_t *);
static void systrace_destroy(void *, dtrace_id_t, void *);
static void systrace_enable(void *, dtrace_id_t, void *);
static void systrace_disable(void *, dtrace_id_t, void *);
static union {
const char **p_constnames;
char **pp_syscallnames;
} uglyhack = { SYSCALLNAMES };
static dtrace_pattr_t systrace_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
};
static dtrace_pops_t systrace_pops = {
systrace_provide,
NULL,
systrace_enable,
systrace_disable,
NULL,
NULL,
systrace_getargdesc,
systrace_getargval,
NULL,
systrace_destroy
};
static dtrace_provider_id_t systrace_id;
#ifdef NATIVE_ABI
/*
* Probe callback function.
*
* Note: This function is called for _all_ syscalls, regardless of which sysent
* array the syscall comes from. It could be a standard syscall or a
* compat syscall from something like Linux.
*/
static void
systrace_probe(struct syscall_args *sa, enum systrace_probe_t type, int retval)
{
uint64_t uargs[nitems(sa->args)];
dtrace_id_t id;
int n_args, sysnum;
sysnum = sa->code;
memset(uargs, 0, sizeof(uargs));
if (type == SYSTRACE_ENTRY) {
if ((id = sa->callp->sy_entry) == DTRACE_IDNONE)
return;
if (sa->callp->sy_systrace_args_func != NULL)
/*
* Convert the syscall parameters using the registered
* function.
*/
(*sa->callp->sy_systrace_args_func)(sysnum, sa->args,
uargs, &n_args);
else
/*
* Use the built-in system call argument conversion
* function to translate the syscall structure fields
* into the array of 64-bit values that DTrace expects.
*/
systrace_args(sysnum, sa->args, uargs, &n_args);
/*
* Save probe arguments now so that we can retrieve them if
* the getargval method is called from further down the stack.
*/
curthread->t_dtrace_systrace_args = uargs;
} else {
if ((id = sa->callp->sy_return) == DTRACE_IDNONE)
return;
curthread->t_dtrace_systrace_args = NULL;
/* Set arg0 and arg1 as the return value of this syscall. */
uargs[0] = uargs[1] = retval;
}
/* Process the probe using the converted argments. */
dtrace_probe(id, uargs[0], uargs[1], uargs[2], uargs[3], uargs[4]);
}
#endif
static void
systrace_getargdesc(void *arg, dtrace_id_t id, void *parg,
dtrace_argdesc_t *desc)
{
int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);
if (SYSTRACE_ISENTRY((uintptr_t)parg))
systrace_entry_setargdesc(sysnum, desc->dtargd_ndx,
desc->dtargd_native, sizeof(desc->dtargd_native));
else
systrace_return_setargdesc(sysnum, desc->dtargd_ndx,
desc->dtargd_native, sizeof(desc->dtargd_native));
if (desc->dtargd_native[0] == '\0')
desc->dtargd_ndx = DTRACE_ARGNONE;
}
static uint64_t
systrace_getargval(void *arg __unused, dtrace_id_t id __unused,
void *parg __unused, int argno, int aframes __unused)
{
uint64_t *uargs;
uargs = curthread->t_dtrace_systrace_args;
if (uargs == NULL)
/* This is a return probe. */
return (0);
if (argno >= nitems(((struct syscall_args *)NULL)->args))
return (0);
return (uargs[argno]);
}
static void
systrace_provide(void *arg, dtrace_probedesc_t *desc)
{
int i;
if (desc != NULL)
return;
for (i = 0; i < MAXSYSCALL; i++) {
if (dtrace_probe_lookup(systrace_id, MODNAME,
uglyhack.pp_syscallnames[i], "entry") != 0)
continue;
(void)dtrace_probe_create(systrace_id, MODNAME,
uglyhack.pp_syscallnames[i], "entry",
SYSTRACE_ARTIFICIAL_FRAMES,
(void *)((uintptr_t)SYSTRACE_ENTRY(i)));
(void)dtrace_probe_create(systrace_id, MODNAME,
uglyhack.pp_syscallnames[i], "return",
SYSTRACE_ARTIFICIAL_FRAMES,
(void *)((uintptr_t)SYSTRACE_RETURN(i)));
}
}
static void
systrace_destroy(void *arg, dtrace_id_t id, void *parg)
{
#ifdef DEBUG
int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);
/*
* There's nothing to do here but assert that we have actually been
* disabled.
*/
if (SYSTRACE_ISENTRY((uintptr_t)parg)) {
ASSERT(sysent[sysnum].sy_entry == 0);
} else {
ASSERT(sysent[sysnum].sy_return == 0);
}
#endif
}
static void
systrace_enable(void *arg, dtrace_id_t id, void *parg)
{
int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);
if (SYSENT[sysnum].sy_systrace_args_func == NULL)
SYSENT[sysnum].sy_systrace_args_func = systrace_args;
if (SYSTRACE_ISENTRY((uintptr_t)parg))
SYSENT[sysnum].sy_entry = id;
else
SYSENT[sysnum].sy_return = id;
}
static void
systrace_disable(void *arg, dtrace_id_t id, void *parg)
{
int sysnum = SYSTRACE_SYSNUM((uintptr_t)parg);
SYSENT[sysnum].sy_entry = 0;
SYSENT[sysnum].sy_return = 0;
}
static void
systrace_load(void *dummy __unused)
{
if (dtrace_register(PROVNAME, &systrace_attr, DTRACE_PRIV_USER, NULL,
&systrace_pops, NULL, &systrace_id) != 0)
return;
#ifdef NATIVE_ABI
systrace_probe_func = systrace_probe;
#endif
}
static void
systrace_unload(void *dummy __unused)
{
#ifdef NATIVE_ABI
systrace_probe_func = NULL;
#endif
if (dtrace_unregister(systrace_id) != 0)
return;
}
static int
systrace_modevent(module_t mod __unused, int type, void *data __unused)
{
int error;
error = 0;
switch (type) {
case MOD_LOAD:
break;
case MOD_UNLOAD:
break;
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
SYSINIT(systrace_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
systrace_load, NULL);
SYSUNINIT(systrace_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
systrace_unload, NULL);
#ifdef LINUX_SYSTRACE
DEV_MODULE(systrace_linux, systrace_modevent, NULL);
MODULE_VERSION(systrace_linux, 1);
#ifdef __amd64__
MODULE_DEPEND(systrace_linux, linux64, 1, 1, 1);
#else
MODULE_DEPEND(systrace_linux, linux, 1, 1, 1);
#endif
MODULE_DEPEND(systrace_linux, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_linux, opensolaris, 1, 1, 1);
#elif defined(LINUX32_SYSTRACE)
DEV_MODULE(systrace_linux32, systrace_modevent, NULL);
MODULE_VERSION(systrace_linux32, 1);
MODULE_DEPEND(systrace_linux32, linux, 1, 1, 1);
MODULE_DEPEND(systrace_linux32, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_linux32, opensolaris, 1, 1, 1);
#elif defined(FREEBSD32_SYSTRACE)
DEV_MODULE(systrace_freebsd32, systrace_modevent, NULL);
MODULE_VERSION(systrace_freebsd32, 1);
MODULE_DEPEND(systrace_freebsd32, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace_freebsd32, opensolaris, 1, 1, 1);
#else
DEV_MODULE(systrace, systrace_modevent, NULL);
MODULE_VERSION(systrace, 1);
MODULE_DEPEND(systrace, dtrace, 1, 1, 1);
MODULE_DEPEND(systrace, opensolaris, 1, 1, 1);
#endif