/* $NetBSD: sys_process.c,v 1.104 2006/07/23 22:06:11 ad Exp $ */ /*- * 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. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * 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 */ /*- * Copyright (c) 1993 Jan-Simon Pendry. * Copyright (c) 1994 Christopher G. Demetriou. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * 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 University of * California, Berkeley and its contributors. * 4. 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 __KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.104 2006/07/23 22:06:11 ad Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Process debugging system call. */ int sys_ptrace(struct lwp *l, 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 *p = l->l_proc; struct lwp *lt, *lr; struct proc *t; /* target process */ struct uio uio; struct iovec iov; struct ptrace_io_desc piod; struct ptrace_lwpinfo pl; struct vmspace *vm; int s, error, write, tmp, size; char *path; /* "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); } /* Can't trace a process that's currently exec'ing. */ 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 (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 is set-id on exec * (unless you're root), or... */ if ((kauth_cred_getuid(t->p_cred) != kauth_cred_getuid(l->l_cred) || ISSET(t->p_flag, P_SUGID)) && (error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, &l->l_acflag)) != 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 == initproc && securelevel > -1) return (EPERM); /* * (6) the tracer is chrooted, and its root directory is * not at or above the root directory of the tracee */ if (!proc_isunder(t, l)) return EPERM; break; case PT_READ_I: case PT_READ_D: case PT_WRITE_I: case PT_WRITE_D: case PT_CONTINUE: case PT_IO: case PT_KILL: case PT_DETACH: case PT_LWPINFO: case PT_SYSCALL: case PT_DUMPCORE: #ifdef PT_STEP case PT_STEP: #endif #ifdef PT_GETREGS case PT_GETREGS: #endif #ifdef PT_SETREGS case PT_SETREGS: #endif #ifdef PT_GETFPREGS case PT_GETFPREGS: #endif #ifdef PT_SETFPREGS case PT_SETFPREGS: #endif #ifdef __HAVE_PTRACE_MACHDEP PTRACE_MACHDEP_REQUEST_CASES #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 being traced by procfs (which has * different signal delivery semantics), */ if (ISSET(t->p_flag, P_FSTRACE)) { uprintf("file system traced\n"); return (EBUSY); } /* * (3) it's not being traced by _you_, or */ if (t->p_pptr != p) { uprintf("parent %d != %d\n", t->p_pptr->p_pid, p->p_pid); return (EBUSY); } /* * (4) it's not currently stopped. */ if (t->p_stat != SSTOP || !ISSET(t->p_flag, P_WAITED)) { uprintf("stat %d flag %d\n", t->p_stat, !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); /* * XXX NJWLWP * * The entire ptrace interface needs work to be useful to a * process with multiple LWPs. For the moment, we'll kluge * this; memory access will be fine, but register access will * be weird. */ lt = proc_representative_lwp(t); /* Now do the operation. */ write = 0; *retval = 0; tmp = 0; switch (SCARG(uap, req)) { case PT_TRACE_ME: /* Just set the trace flag. */ SET(t->p_flag, P_TRACED); t->p_opptr = t->p_pptr; return (0); case PT_WRITE_I: /* XXX no separate I and D spaces */ case PT_WRITE_D: #if defined(__HAVE_RAS) /* * Can't write to a RAS */ if (!LIST_EMPTY(&t->p_raslist) && (ras_lookup(t, SCARG(uap, addr)) != (caddr_t)-1)) { return (EACCES); } #endif write = 1; tmp = 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)&tmp; iov.iov_len = sizeof(tmp); uio.uio_iov = &iov; uio.uio_iovcnt = 1; uio.uio_offset = (off_t)(unsigned long)SCARG(uap, addr); uio.uio_resid = sizeof(tmp); uio.uio_rw = write ? UIO_WRITE : UIO_READ; UIO_SETUP_SYSSPACE(&uio); error = process_domem(l, lt, &uio); if (!write) *retval = tmp; 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)(unsigned long)piod.piod_offs; uio.uio_resid = piod.piod_len; error = proc_vmspace_getref(l->l_proc, &vm); if (error) { return error; } uio.uio_vmspace = vm; switch (piod.piod_op) { case PIOD_READ_D: case PIOD_READ_I: uio.uio_rw = UIO_READ; break; case PIOD_WRITE_D: case PIOD_WRITE_I: uio.uio_rw = UIO_WRITE; break; default: return (EINVAL); } error = process_domem(l, lt, &uio); piod.piod_len -= uio.uio_resid; (void) copyout(&piod, SCARG(uap, addr), sizeof(piod)); uvmspace_free(vm); return (error); case PT_DUMPCORE: if ((path = SCARG(uap, addr)) != NULL) { char *dst; int len = SCARG(uap, data); if (len >= MAXPATHLEN) return EINVAL; dst = malloc(len + 1, M_TEMP, M_WAITOK); if ((error = copyin(path, dst, len)) != 0) { free(dst, M_TEMP); return error; } path = dst; path[len] = '\0'; } error = coredump(lt, path); if (path) free(path, M_TEMP); 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: case PT_SYSCALL: case PT_DETACH: if (SCARG(uap, req) == PT_SYSCALL) { if (!ISSET(t->p_flag, P_SYSCALL)) { SET(t->p_flag, P_SYSCALL); #ifdef __HAVE_SYSCALL_INTERN (*t->p_emul->e_syscall_intern)(t); #endif } } else { if (ISSET(t->p_flag, P_SYSCALL)) { CLR(t->p_flag, P_SYSCALL); #ifdef __HAVE_SYSCALL_INTERN (*t->p_emul->e_syscall_intern)(t); #endif } } /* * 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); PHOLD(lt); /* If the address parameter is not (int *)1, set the pc. */ if ((int *)SCARG(uap, addr) != (int *)1) if ((error = process_set_pc(lt, SCARG(uap, addr))) != 0) goto relebad; #ifdef PT_STEP /* * Arrange for a single-step, if that's requested and possible. */ error = process_sstep(lt, SCARG(uap, req) == PT_STEP); if (error) goto relebad; #endif PRELE(lt); if (SCARG(uap, req) == PT_DETACH) { /* give process back to original parent or init */ s = proclist_lock_write(); if (t->p_opptr != t->p_pptr) { struct proc *pp = t->p_opptr; proc_reparent(t, pp ? pp : initproc); } /* not being traced any more */ t->p_opptr = NULL; proclist_unlock_write(s); CLR(t->p_flag, P_TRACED|P_WAITED|P_SYSCALL|P_FSTRACE); } sendsig: /* Finally, deliver the requested signal (or none). */ if (t->p_stat == SSTOP) { t->p_xstat = SCARG(uap, data); SCHED_LOCK(s); lr = proc_unstop(t); /* * If the target needs to take a signal, there * is no running LWP that will see it, and * there is a LWP sleeping interruptably, then * get it moving. */ if (lr && (t->p_xstat != 0)) setrunnable(lr); SCHED_UNLOCK(s); } else { if (SCARG(uap, data) != 0) psignal(t, SCARG(uap, data)); } return (0); relebad: PRELE(lt); 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: /* * 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. */ SET(t->p_flag, P_TRACED); s = proclist_lock_write(); t->p_opptr = t->p_pptr; if (t->p_pptr != p) { t->p_pptr->p_flag |= P_CHTRACED; proc_reparent(t, p); } proclist_unlock_write(s); SCARG(uap, data) = SIGSTOP; goto sendsig; case PT_LWPINFO: size = SCARG(uap, data); if (size < sizeof(lwpid_t)) return (EINVAL); error = copyin(SCARG(uap, addr), &pl, sizeof(lwpid_t)); if (error) return (error); tmp = pl.pl_lwpid; if (tmp == 0) lt = LIST_FIRST(&t->p_lwps); else { LIST_FOREACH(lt, &t->p_lwps, l_sibling) if (lt->l_lid == tmp) break; if (lt == NULL) return (ESRCH); lt = LIST_NEXT(lt, l_sibling); } pl.pl_lwpid = 0; pl.pl_event = 0; if (lt) { pl.pl_lwpid = lt->l_lid; if (lt->l_lid == t->p_sigctx.ps_lwp) pl.pl_event = PL_EVENT_SIGNAL; } error = copyout(&pl, SCARG(uap, addr), SCARG(uap, data)); return (0); #ifdef PT_SETREGS case PT_SETREGS: write = 1; #endif #ifdef PT_GETREGS case PT_GETREGS: /* write = 0 done above. */ #endif #if defined(PT_SETREGS) || defined(PT_GETREGS) tmp = SCARG(uap, data); if (tmp != 0 && t->p_nlwps > 1) { LIST_FOREACH(lt, &t->p_lwps, l_sibling) if (lt->l_lid == tmp) break; if (lt == NULL) return (ESRCH); } if (!process_validregs(proc_representative_lwp(t))) return (EINVAL); else { error = proc_vmspace_getref(l->l_proc, &vm); if (error) { return error; } iov.iov_base = SCARG(uap, addr); iov.iov_len = sizeof(struct reg); uio.uio_iov = &iov; uio.uio_iovcnt = 1; uio.uio_offset = 0; uio.uio_resid = sizeof(struct reg); uio.uio_rw = write ? UIO_WRITE : UIO_READ; uio.uio_vmspace = vm; error = process_doregs(l, lt, &uio); uvmspace_free(vm); return error; } #endif #ifdef PT_SETFPREGS case PT_SETFPREGS: write = 1; #endif #ifdef PT_GETFPREGS case PT_GETFPREGS: /* write = 0 done above. */ #endif #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) tmp = SCARG(uap, data); if (tmp != 0 && t->p_nlwps > 1) { LIST_FOREACH(lt, &t->p_lwps, l_sibling) if (lt->l_lid == tmp) break; if (lt == NULL) return (ESRCH); } if (!process_validfpregs(proc_representative_lwp(t))) return (EINVAL); else { error = proc_vmspace_getref(l->l_proc, &vm); if (error) { return error; } iov.iov_base = SCARG(uap, addr); iov.iov_len = sizeof(struct fpreg); uio.uio_iov = &iov; uio.uio_iovcnt = 1; uio.uio_offset = 0; uio.uio_resid = sizeof(struct fpreg); uio.uio_rw = write ? UIO_WRITE : UIO_READ; uio.uio_vmspace = vm; error = process_dofpregs(l, lt, &uio); uvmspace_free(vm); return error; } #endif #ifdef __HAVE_PTRACE_MACHDEP PTRACE_MACHDEP_REQUEST_CASES return (ptrace_machdep_dorequest(l, lt, SCARG(uap, req), SCARG(uap, addr), SCARG(uap, data))); #endif } #ifdef DIAGNOSTIC panic("ptrace: impossible"); #endif return 0; } int process_doregs(struct lwp *curl /*tracer*/, struct lwp *l /*traced*/, struct uio *uio) { #if defined(PT_GETREGS) || defined(PT_SETREGS) struct proc *p = l->l_proc; int error; struct reg r; char *kv; int kl; if (uio->uio_offset < 0 || uio->uio_offset > (off_t)sizeof(r)) return EINVAL; if ((error = process_checkioperm(curl, p)) != 0) return error; kl = sizeof(r); kv = (char *)&r; kv += uio->uio_offset; kl -= uio->uio_offset; if ((size_t)kl > uio->uio_resid) kl = uio->uio_resid; PHOLD(l); error = process_read_regs(l, &r); if (error == 0) error = uiomove(kv, kl, uio); if (error == 0 && uio->uio_rw == UIO_WRITE) { if (l->l_stat != LSSTOP) error = EBUSY; else error = process_write_regs(l, &r); } PRELE(l); uio->uio_offset = 0; return (error); #else return (EINVAL); #endif } int process_validregs(struct lwp *l) { #if defined(PT_SETREGS) || defined(PT_GETREGS) return ((l->l_proc->p_flag & P_SYSTEM) == 0); #else return (0); #endif } int process_dofpregs(struct lwp *curl /*tracer*/, struct lwp *l /*traced*/, struct uio *uio) { #if defined(PT_GETFPREGS) || defined(PT_SETFPREGS) struct proc *p = l->l_proc; int error; struct fpreg r; char *kv; int kl; if (uio->uio_offset < 0 || uio->uio_offset > (off_t)sizeof(r)) return EINVAL; if ((error = process_checkioperm(curl, p)) != 0) return (error); kl = sizeof(r); kv = (char *)&r; kv += uio->uio_offset; kl -= uio->uio_offset; if ((size_t)kl > uio->uio_resid) kl = uio->uio_resid; PHOLD(l); error = process_read_fpregs(l, &r); if (error == 0) error = uiomove(kv, kl, uio); if (error == 0 && uio->uio_rw == UIO_WRITE) { if (l->l_stat != LSSTOP) error = EBUSY; else error = process_write_fpregs(l, &r); } PRELE(l); uio->uio_offset = 0; return (error); #else return (EINVAL); #endif } int process_validfpregs(struct lwp *l) { #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) return ((l->l_proc->p_flag & P_SYSTEM) == 0); #else return (0); #endif } int process_domem(struct lwp *curl /*tracer*/, struct lwp *l /*traced*/, struct uio *uio) { struct proc *p = l->l_proc; /* traced */ struct vmspace *vm; int error; size_t len; #ifdef PMAP_NEED_PROCWR vaddr_t addr; #endif len = uio->uio_resid; if (len == 0) return (0); #ifdef PMAP_NEED_PROCWR addr = uio->uio_offset; #endif if ((error = process_checkioperm(curl, p)) != 0) return (error); vm = p->p_vmspace; simple_lock(&vm->vm_map.ref_lock); if ((p->p_flag & P_WEXIT) || vm->vm_refcnt < 1) error = EFAULT; if (error == 0) p->p_vmspace->vm_refcnt++; /* XXX */ simple_unlock(&vm->vm_map.ref_lock); if (error != 0) return (error); error = uvm_io(&vm->vm_map, uio); uvmspace_free(vm); #ifdef PMAP_NEED_PROCWR if (error == 0 && uio->uio_rw == UIO_WRITE) pmap_procwr(p, addr, len); #endif return (error); } /* * Ensure that a process has permission to perform I/O on another. * Arguments: * p The process wishing to do the I/O (the tracer). * t The process who's memory/registers will be read/written. */ int process_checkioperm(struct lwp *l, struct proc *t) { int error; /* * You cannot attach to a processes mem/regs if: * * (1) It is currently exec'ing */ if (ISSET(t->p_flag, P_INEXEC)) return (EAGAIN); /* * (2) it's not owned by you, or is set-id on exec * (unless you're root), or... */ if ((kauth_cred_getuid(t->p_cred) != kauth_cred_getuid(l->l_cred) || ISSET(t->p_flag, P_SUGID)) && (error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER, &l->l_acflag)) != 0) return (error); /* * (3) ...it's init, which controls the security level * of the entire system, and the system was not * compiled with permanetly insecure mode turned on. */ if (t == initproc && securelevel > -1) return (EPERM); /* * (4) the tracer is chrooted, and its root directory is * not at or above the root directory of the tracee */ if (!proc_isunder(t, l)) return (EPERM); return (0); } void process_stoptrace(struct lwp *l) { int s = 0, dolock = (l->l_flag & L_SINTR) == 0; struct proc *p = l->l_proc, *pp = p->p_pptr; if (pp->p_pid == 1) { CLR(p->p_flag, P_SYSCALL); return; } p->p_xstat = SIGTRAP; child_psignal(pp, dolock); if (dolock) SCHED_LOCK(s); proc_stop(p, 1); mi_switch(l, NULL); SCHED_ASSERT_UNLOCKED(); if (dolock) splx(s); }