/* $OpenBSD: sys_process.c,v 1.39 2007/04/10 17:47:55 miod Exp $ */
/* $NetBSD: sys_process.c,v 1.55 1996/05/15 06:17:47 tls Exp $ */
/*-
* Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, 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. Neither the name of the University 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 REGENTS 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 REGENTS 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.
*
* from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
*/
/*
* References:
* (1) Bach's "The Design of the UNIX Operating System",
* (2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution,
* (3) the "4.4BSD Programmer's Reference Manual" published
* by USENIX and O'Reilly & Associates.
* The 4.4BSD PRM does a reasonably good job of documenting what the various
* ptrace() requests should actually do, and its text is quoted several times
* in this file.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <sys/user.h>
#include <sys/sched.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <uvm/uvm_extern.h>
#include <machine/reg.h>
#ifdef PTRACE
/*
* Process debugging system call.
*/
int
sys_ptrace(struct proc *p, void *v, register_t *retval)
{
struct sys_ptrace_args /* {
syscallarg(int) req;
syscallarg(pid_t) pid;
syscallarg(caddr_t) addr;
syscallarg(int) data;
} */ *uap = v;
struct proc *t; /* target process */
struct uio uio;
struct iovec iov;
struct ptrace_io_desc piod;
struct ptrace_event pe;
struct reg *regs;
#if defined (PT_SETFPREGS) || defined (PT_GETFPREGS)
struct fpreg *fpregs;
#endif
#if defined (PT_SETXMMREGS) || defined (PT_GETXMMREGS)
struct xmmregs *xmmregs;
#endif
#ifdef PT_WCOOKIE
register_t wcookie;
#endif
int error, write;
int temp;
int req;
int s;
/* "A foolish consistency..." XXX */
if (SCARG(uap, req) == PT_TRACE_ME)
t = p;
else {
/* Find the process we're supposed to be operating on. */
if ((t = pfind(SCARG(uap, pid))) == NULL)
return (ESRCH);
}
if ((t->p_flag & P_INEXEC) != 0)
return (EAGAIN);
/* Make sure we can operate on it. */
switch (SCARG(uap, req)) {
case PT_TRACE_ME:
/* Saying that you're being traced is always legal. */
break;
case PT_ATTACH:
/*
* You can't attach to a process if:
* (1) it's the process that's doing the attaching,
*/
if (t->p_pid == p->p_pid)
return (EINVAL);
/*
* (2) it's a system process
*/
if (ISSET(t->p_flag, P_SYSTEM))
return (EPERM);
/*
* (3) it's already being traced, or
*/
if (ISSET(t->p_flag, P_TRACED))
return (EBUSY);
/*
* (4) it's not owned by you, or the last exec
* gave us setuid/setgid privs (unless
* you're root), or...
*
* [Note: once P_SUGID or P_SUGIDEXEC gets set in
* execve(), they stay set until the process does
* another execve(). Hence this prevents a setuid
* process which revokes its special privileges using
* setuid() from being traced. This is good security.]
*/
if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
ISSET(t->p_flag, P_SUGIDEXEC) ||
ISSET(t->p_flag, P_SUGID)) &&
(error = suser(p, 0)) != 0)
return (error);
/*
* (5) ...it's init, which controls the security level
* of the entire system, and the system was not
* compiled with permanently insecure mode turned
* on.
*/
if ((t->p_pid == 1) && (securelevel > -1))
return (EPERM);
break;
case PT_READ_I:
case PT_READ_D:
case PT_WRITE_I:
case PT_WRITE_D:
case PT_IO:
case PT_CONTINUE:
case PT_KILL:
case PT_DETACH:
#ifdef PT_STEP
case PT_STEP:
#endif
case PT_SET_EVENT_MASK:
case PT_GET_EVENT_MASK:
case PT_GET_PROCESS_STATE:
case PT_GETREGS:
case PT_SETREGS:
#ifdef PT_GETFPREGS
case PT_GETFPREGS:
#endif
#ifdef PT_SETFPREGS
case PT_SETFPREGS:
#endif
#ifdef PT_GETXMMREGS
case PT_GETXMMREGS:
#endif
#ifdef PT_SETXMMREGS
case PT_SETXMMREGS:
#endif
#ifdef PT_WCOOKIE
case PT_WCOOKIE:
#endif
/*
* You can't do what you want to the process if:
* (1) It's not being traced at all,
*/
if (!ISSET(t->p_flag, P_TRACED))
return (EPERM);
/*
* (2) it's not being traced by _you_, or
*/
if (t->p_pptr != p)
return (EBUSY);
/*
* (3) it's not currently stopped.
*/
if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED))
return (EBUSY);
break;
default: /* It was not a legal request. */
return (EINVAL);
}
/* Do single-step fixup if needed. */
FIX_SSTEP(t);
/* Now do the operation. */
write = 0;
*retval = 0;
switch (SCARG(uap, req)) {
case PT_TRACE_ME:
/* Just set the trace flag. */
atomic_setbits_int(&t->p_flag, P_TRACED);
t->p_oppid = t->p_pptr->p_pid;
if (t->p_ptstat == NULL)
t->p_ptstat = malloc(sizeof(*t->p_ptstat),
M_SUBPROC, M_WAITOK);
bzero(t->p_ptstat, sizeof(*t->p_ptstat));
return (0);
case PT_WRITE_I: /* XXX no separate I and D spaces */
case PT_WRITE_D:
write = 1;
temp = SCARG(uap, data);
case PT_READ_I: /* XXX no separate I and D spaces */
case PT_READ_D:
/* write = 0 done above. */
iov.iov_base = (caddr_t)&temp;
iov.iov_len = sizeof(int);
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = (off_t)(long)SCARG(uap, addr);
uio.uio_resid = sizeof(int);
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_rw = write ? UIO_WRITE : UIO_READ;
uio.uio_procp = p;
error = process_domem(p, t, &uio, write ? PT_WRITE_I :
PT_READ_I);
if (write == 0)
*retval = temp;
return (error);
case PT_IO:
error = copyin(SCARG(uap, addr), &piod, sizeof(piod));
if (error)
return (error);
iov.iov_base = piod.piod_addr;
iov.iov_len = piod.piod_len;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = (off_t)(long)piod.piod_offs;
uio.uio_resid = piod.piod_len;
uio.uio_segflg = UIO_USERSPACE;
uio.uio_procp = p;
switch (piod.piod_op) {
case PIOD_READ_I:
req = PT_READ_I;
uio.uio_rw = UIO_READ;
break;
case PIOD_READ_D:
req = PT_READ_D;
uio.uio_rw = UIO_READ;
break;
case PIOD_WRITE_I:
req = PT_WRITE_I;
uio.uio_rw = UIO_WRITE;
break;
case PIOD_WRITE_D:
req = PT_WRITE_D;
uio.uio_rw = UIO_WRITE;
break;
default:
return (EINVAL);
}
error = process_domem(p, t, &uio, req);
piod.piod_len -= uio.uio_resid;
(void) copyout(&piod, SCARG(uap, addr), sizeof(piod));
return (error);
#ifdef PT_STEP
case PT_STEP:
/*
* From the 4.4BSD PRM:
* "Execution continues as in request PT_CONTINUE; however
* as soon as possible after execution of at least one
* instruction, execution stops again. [ ... ]"
*/
#endif
case PT_CONTINUE:
/*
* From the 4.4BSD PRM:
* "The data argument is taken as a signal number and the
* child's execution continues at location addr as if it
* incurred that signal. Normally the signal number will
* be either 0 to indicate that the signal that caused the
* stop should be ignored, or that value fetched out of
* the process's image indicating which signal caused
* the stop. If addr is (int *)1 then execution continues
* from where it stopped."
*/
/* Check that the data is a valid signal number or zero. */
if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG)
return (EINVAL);
/* If the address parameter is not (int *)1, set the pc. */
if ((int *)SCARG(uap, addr) != (int *)1)
if ((error = process_set_pc(t, SCARG(uap, addr))) != 0)
goto relebad;
#ifdef PT_STEP
/*
* Arrange for a single-step, if that's requested and possible.
*/
error = process_sstep(t, SCARG(uap, req) == PT_STEP);
if (error)
goto relebad;
#endif
goto sendsig;
case PT_DETACH:
/*
* From the 4.4BSD PRM:
* "The data argument is taken as a signal number and the
* child's execution continues at location addr as if it
* incurred that signal. Normally the signal number will
* be either 0 to indicate that the signal that caused the
* stop should be ignored, or that value fetched out of
* the process's image indicating which signal caused
* the stop. If addr is (int *)1 then execution continues
* from where it stopped."
*/
/* Check that the data is a valid signal number or zero. */
if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG)
return (EINVAL);
#ifdef PT_STEP
/*
* Arrange for a single-step, if that's requested and possible.
*/
error = process_sstep(t, SCARG(uap, req) == PT_STEP);
if (error)
goto relebad;
#endif
/* give process back to original parent or init */
if (t->p_oppid != t->p_pptr->p_pid) {
struct proc *pp;
pp = pfind(t->p_oppid);
proc_reparent(t, pp ? pp : initproc);
}
/* not being traced any more */
t->p_oppid = 0;
atomic_clearbits_int(&t->p_flag, P_TRACED|P_WAITED);
sendsig:
bzero(t->p_ptstat, sizeof(*t->p_ptstat));
/* Finally, deliver the requested signal (or none). */
if (t->p_stat == SSTOP) {
t->p_xstat = SCARG(uap, data);
SCHED_LOCK(s);
setrunnable(t);
SCHED_UNLOCK(s);
} else {
if (SCARG(uap, data) != 0)
psignal(t, SCARG(uap, data));
}
return (0);
relebad:
return (error);
case PT_KILL:
/* just send the process a KILL signal. */
SCARG(uap, data) = SIGKILL;
goto sendsig; /* in PT_CONTINUE, above. */
case PT_ATTACH:
/*
* As done in procfs:
* Go ahead and set the trace flag.
* Save the old parent (it's reset in
* _DETACH, and also in kern_exit.c:wait4()
* Reparent the process so that the tracing
* proc gets to see all the action.
* Stop the target.
*/
atomic_setbits_int(&t->p_flag, P_TRACED);
t->p_oppid = t->p_pptr->p_pid;
if (t->p_pptr != p)
proc_reparent(t, p);
if (t->p_ptstat == NULL)
t->p_ptstat = malloc(sizeof(*t->p_ptstat),
M_SUBPROC, M_WAITOK);
SCARG(uap, data) = SIGSTOP;
goto sendsig;
case PT_GET_EVENT_MASK:
if (SCARG(uap, data) != sizeof(pe))
return (EINVAL);
bzero(&pe, sizeof(pe));
pe.pe_set_event = t->p_ptmask;
return (copyout(&pe, SCARG(uap, addr), sizeof(pe)));
case PT_SET_EVENT_MASK:
if (SCARG(uap, data) != sizeof(pe))
return (EINVAL);
if ((error = copyin(SCARG(uap, addr), &pe, sizeof(pe))))
return (error);
t->p_ptmask = pe.pe_set_event;
return (0);
case PT_GET_PROCESS_STATE:
if (SCARG(uap, data) != sizeof(*t->p_ptstat))
return (EINVAL);
return (copyout(t->p_ptstat, SCARG(uap, addr),
sizeof(*t->p_ptstat)));
case PT_SETREGS:
KASSERT((p->p_flag & P_SYSTEM) == 0);
if ((error = process_checkioperm(p, t)) != 0)
return (error);
regs = malloc(sizeof(*regs), M_TEMP, M_WAITOK);
error = copyin(SCARG(uap, addr), regs, sizeof(*regs));
if (error == 0) {
error = process_write_regs(t, regs);
}
free(regs, M_TEMP);
return (error);
case PT_GETREGS:
KASSERT((p->p_flag & P_SYSTEM) == 0);
if ((error = process_checkioperm(p, t)) != 0)
return (error);
regs = malloc(sizeof(*regs), M_TEMP, M_WAITOK);
error = process_read_regs(t, regs);
if (error == 0)
error = copyout(regs,
SCARG(uap, addr), sizeof (*regs));
free(regs, M_TEMP);
return (error);
#ifdef PT_SETFPREGS
case PT_SETFPREGS:
KASSERT((p->p_flag & P_SYSTEM) == 0);
if ((error = process_checkioperm(p, t)) != 0)
return (error);
fpregs = malloc(sizeof(*fpregs), M_TEMP, M_WAITOK);
error = copyin(SCARG(uap, addr), fpregs, sizeof(*fpregs));
if (error == 0) {
error = process_write_fpregs(t, fpregs);
}
free(fpregs, M_TEMP);
return (error);
#endif
#ifdef PT_GETFPREGS
case PT_GETFPREGS:
KASSERT((p->p_flag & P_SYSTEM) == 0);
if ((error = process_checkioperm(p, t)) != 0)
return (error);
fpregs = malloc(sizeof(*fpregs), M_TEMP, M_WAITOK);
error = process_read_fpregs(t, fpregs);
if (error == 0)
error = copyout(fpregs,
SCARG(uap, addr), sizeof(*fpregs));
free(fpregs, M_TEMP);
return (error);
#endif
#ifdef PT_SETXMMREGS
case PT_SETXMMREGS:
KASSERT((p->p_flag & P_SYSTEM) == 0);
if ((error = process_checkioperm(p, t)) != 0)
return (error);
xmmregs = malloc(sizeof(*xmmregs), M_TEMP, M_WAITOK);
error = copyin(SCARG(uap, addr), xmmregs, sizeof(*xmmregs));
if (error == 0) {
error = process_write_xmmregs(t, xmmregs);
}
free(xmmregs, M_TEMP);
return (error);
#endif
#ifdef PT_GETXMMREGS
case PT_GETXMMREGS:
KASSERT((p->p_flag & P_SYSTEM) == 0);
if ((error = process_checkioperm(p, t)) != 0)
return (error);
xmmregs = malloc(sizeof(*xmmregs), M_TEMP, M_WAITOK);
error = process_read_xmmregs(t, xmmregs);
if (error == 0)
error = copyout(xmmregs,
SCARG(uap, addr), sizeof(*xmmregs));
free(xmmregs, M_TEMP);
return (error);
#endif
#ifdef PT_WCOOKIE
case PT_WCOOKIE:
wcookie = process_get_wcookie (t);
return (copyout(&wcookie, SCARG(uap, addr),
sizeof (register_t)));
#endif
}
#ifdef DIAGNOSTIC
panic("ptrace: impossible");
#endif
return 0;
}
#endif /* PTRACE */
/*
* Check if a process is allowed to fiddle with the memory of another.
*
* p = tracer
* t = tracee
*
* 1. You can't attach to a process not owned by you or one that has raised
* its privileges.
* 1a. ...unless you are root.
*
* 2. init is always off-limits because it can control the securelevel.
* 2a. ...unless securelevel is permanently set to insecure.
*
* 3. Processes that are in the process of doing an exec() are always
* off-limits because of the can of worms they are. Just wait a
* second.
*/
int
process_checkioperm(struct proc *p, struct proc *t)
{
int error;
if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
ISSET(t->p_flag, P_SUGIDEXEC) ||
ISSET(t->p_flag, P_SUGID)) &&
(error = suser(p, 0)) != 0)
return (error);
if ((t->p_pid == 1) && (securelevel > -1))
return (EPERM);
if (t->p_flag & P_INEXEC)
return (EAGAIN);
return (0);
}
int
process_domem(struct proc *curp, struct proc *p, struct uio *uio, int req)
{
int error;
vaddr_t addr;
vsize_t len;
len = uio->uio_resid;
if (len == 0)
return (0);
if ((error = process_checkioperm(curp, p)) != 0)
return (error);
/* XXXCDC: how should locking work here? */
if ((p->p_flag & P_WEXIT) || (p->p_vmspace->vm_refcnt < 1))
return(EFAULT);
addr = uio->uio_offset;
p->p_vmspace->vm_refcnt++; /* XXX */
error = uvm_io(&p->p_vmspace->vm_map, uio,
(req == PT_WRITE_I) ? UVM_IO_FIXPROT : 0);
uvmspace_free(p->p_vmspace);
if (error == 0 && req == PT_WRITE_I)
pmap_proc_iflush(p, addr, len);
return (error);
}
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