02eb342b57
gets reset properly when the old parent exits before the child. A flag is set in old parent process when the child is reparented in ptrace(2). If it's set when process is exiting, all running processes have their 'old parent process' pointer checked and reset if appropriate. Also change to use 'struct proc *' pointer directly, rather than pid_t. This fixes security/14444 by David Sainty. Reviewed by Christos Zoulas.
343 lines
8.9 KiB
C
343 lines
8.9 KiB
C
/* $NetBSD: procfs_ctl.c,v 1.23 2002/07/25 20:04:03 jdolecek Exp $ */
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/*
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* Copyright (c) 1993 Jan-Simon Pendry
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)procfs_ctl.c 8.4 (Berkeley) 6/15/94
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: procfs_ctl.c,v 1.23 2002/07/25 20:04:03 jdolecek Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/ioctl.h>
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#include <sys/tty.h>
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#include <sys/resource.h>
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#include <sys/resourcevar.h>
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#include <sys/signalvar.h>
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#include <miscfs/procfs/procfs.h>
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#define PROCFS_CTL_ATTACH 1
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#define PROCFS_CTL_DETACH 2
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#define PROCFS_CTL_STEP 3
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#define PROCFS_CTL_RUN 4
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#define PROCFS_CTL_WAIT 5
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static const vfs_namemap_t ctlnames[] = {
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/* special /proc commands */
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{ "attach", PROCFS_CTL_ATTACH },
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{ "detach", PROCFS_CTL_DETACH },
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{ "step", PROCFS_CTL_STEP },
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{ "run", PROCFS_CTL_RUN },
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{ "wait", PROCFS_CTL_WAIT },
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{ 0 },
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};
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static const vfs_namemap_t signames[] = {
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/* regular signal names */
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{ "hup", SIGHUP }, { "int", SIGINT },
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{ "quit", SIGQUIT }, { "ill", SIGILL },
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{ "trap", SIGTRAP }, { "abrt", SIGABRT },
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{ "iot", SIGIOT }, { "emt", SIGEMT },
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{ "fpe", SIGFPE }, { "kill", SIGKILL },
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{ "bus", SIGBUS }, { "segv", SIGSEGV },
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{ "sys", SIGSYS }, { "pipe", SIGPIPE },
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{ "alrm", SIGALRM }, { "term", SIGTERM },
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{ "urg", SIGURG }, { "stop", SIGSTOP },
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{ "tstp", SIGTSTP }, { "cont", SIGCONT },
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{ "chld", SIGCHLD }, { "ttin", SIGTTIN },
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{ "ttou", SIGTTOU }, { "io", SIGIO },
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{ "xcpu", SIGXCPU }, { "xfsz", SIGXFSZ },
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{ "vtalrm", SIGVTALRM }, { "prof", SIGPROF },
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{ "winch", SIGWINCH }, { "info", SIGINFO },
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{ "usr1", SIGUSR1 }, { "usr2", SIGUSR2 },
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{ 0 },
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};
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int procfs_control __P((struct proc *, struct proc *, int, int));
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/* Macros to clear/set/test flags. */
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#define SET(t, f) (t) |= (f)
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#define CLR(t, f) (t) &= ~(f)
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#define ISSET(t, f) ((t) & (f))
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int
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procfs_control(curp, p, op, sig)
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struct proc *curp;
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struct proc *p;
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int op, sig;
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{
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int s, error;
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/*
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* You cannot do anything to the process if it is currently exec'ing
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*/
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if (ISSET(p->p_flag, P_INEXEC))
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return (EAGAIN);
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switch (op) {
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/*
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* Attach - attaches the target process for debugging
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* by the calling process.
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*/
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case PROCFS_CTL_ATTACH:
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/*
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* You can't attach to a process if:
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* (1) it's the process that's doing the attaching,
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*/
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if (p->p_pid == curp->p_pid)
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return (EINVAL);
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/*
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* (2) it's already being traced, or
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*/
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if (ISSET(p->p_flag, P_TRACED))
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return (EBUSY);
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/*
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* (3) it's not owned by you, or is set-id on exec
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* (unless you're root), or...
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*/
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if ((p->p_cred->p_ruid != curp->p_cred->p_ruid ||
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ISSET(p->p_flag, P_SUGID)) &&
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(error = suser(curp->p_ucred, &curp->p_acflag)) != 0)
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return (error);
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/*
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* (4) ...it's init, which controls the security level
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* of the entire system, and the system was not
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* compiled with permanently insecure mode turned
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* on.
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*/
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if (p == initproc && securelevel > -1)
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return (EPERM);
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break;
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/*
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* Target process must be stopped, owned by (curp) and
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* be set up for tracing (P_TRACED flag set).
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* Allow DETACH to take place at any time for sanity.
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* Allow WAIT any time, of course.
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*
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* Note that the semantics of DETACH are different here
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* from ptrace(2).
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*/
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case PROCFS_CTL_DETACH:
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case PROCFS_CTL_WAIT:
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/*
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* You can't do what you want to the process if:
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* (1) It's not being traced at all,
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*/
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if (!ISSET(p->p_flag, P_TRACED))
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return (EPERM);
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/*
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* (2) it's being traced by ptrace(2) (which has
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* different signal delivery semantics), or
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*/
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if (!ISSET(p->p_flag, P_FSTRACE))
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return (EBUSY);
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/*
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* (3) it's not being traced by _you_.
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*/
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if (p->p_pptr != curp)
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return (EBUSY);
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break;
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default:
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/*
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* You can't do what you want to the process if:
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* (1) It's not being traced at all,
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*/
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if (!ISSET(p->p_flag, P_TRACED))
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return (EPERM);
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/*
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* (2) it's being traced by ptrace(2) (which has
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* different signal delivery semantics),
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*/
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if (!ISSET(p->p_flag, P_FSTRACE))
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return (EBUSY);
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/*
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* (3) it's not being traced by _you_, or
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*/
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if (p->p_pptr != curp)
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return (EBUSY);
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/*
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* (4) it's not currently stopped.
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*/
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if (p->p_stat != SSTOP || !ISSET(p->p_flag, P_WAITED))
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return (EBUSY);
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break;
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}
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/* Do single-step fixup if needed. */
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FIX_SSTEP(p);
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switch (op) {
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case PROCFS_CTL_ATTACH:
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/*
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* Go ahead and set the trace flag.
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* Save the old parent (it's reset in
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* _DETACH, and also in kern_exit.c:wait4()
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* Reparent the process so that the tracing
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* proc gets to see all the action.
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* Stop the target.
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*/
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SET(p->p_flag, P_TRACED|P_FSTRACE);
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p->p_opptr = p->p_pptr;
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if (p->p_pptr != curp) {
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p->p_pptr->p_flag |= P_CHTRACED;
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proc_reparent(p, curp);
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}
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sig = SIGSTOP;
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goto sendsig;
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#ifdef PT_STEP
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case PROCFS_CTL_STEP:
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/*
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* Step. Let the target process execute a single instruction.
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*/
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#endif
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case PROCFS_CTL_RUN:
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case PROCFS_CTL_DETACH:
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#ifdef PT_STEP
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PHOLD(p);
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error = process_sstep(p, op == PROCFS_CTL_STEP);
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PRELE(p);
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if (error)
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return (error);
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#endif
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if (op == PROCFS_CTL_DETACH) {
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/* give process back to original parent */
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if (p->p_opptr != p->p_pptr) {
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struct proc *pp = p->p_opptr;
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proc_reparent(p, pp ? pp : initproc);
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}
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/* not being traced any more */
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p->p_opptr = NULL;
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CLR(p->p_flag, P_TRACED|P_FSTRACE|P_WAITED);
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}
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sendsig:
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/* Finally, deliver the requested signal (or none). */
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if (p->p_stat == SSTOP) {
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p->p_xstat = sig;
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SCHED_LOCK(s);
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setrunnable(p);
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SCHED_UNLOCK(s);
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} else {
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if (sig != 0)
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psignal(p, sig);
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}
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return (0);
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case PROCFS_CTL_WAIT:
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/*
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* Wait for the target process to stop.
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*/
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while (p->p_stat != SSTOP && P_ZOMBIE(p)) {
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error = tsleep(p, PWAIT|PCATCH, "procfsx", 0);
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if (error)
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return (error);
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}
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return (0);
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}
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panic("procfs_control");
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}
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int
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procfs_doctl(curp, p, pfs, uio)
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struct proc *curp;
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struct pfsnode *pfs;
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struct uio *uio;
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struct proc *p;
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{
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int xlen;
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int error;
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char msg[PROCFS_CTLLEN+1];
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const vfs_namemap_t *nm;
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if (uio->uio_rw != UIO_WRITE)
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return (EOPNOTSUPP);
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xlen = PROCFS_CTLLEN;
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error = vfs_getuserstr(uio, msg, &xlen);
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if (error)
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return (error);
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/*
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* Map signal names into signal generation
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* or debug control. Unknown commands and/or signals
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* return EOPNOTSUPP.
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*
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* Sending a signal while the process is being debugged
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* also has the side effect of letting the target continue
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* to run. There is no way to single-step a signal delivery.
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*/
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error = EOPNOTSUPP;
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nm = vfs_findname(ctlnames, msg, xlen);
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if (nm) {
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error = procfs_control(curp, p, nm->nm_val, 0);
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} else {
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nm = vfs_findname(signames, msg, xlen);
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if (nm) {
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if (ISSET(p->p_flag, P_TRACED) &&
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p->p_pptr == curp)
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error = procfs_control(curp, p, PROCFS_CTL_RUN,
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nm->nm_val);
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else {
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psignal(p, nm->nm_val);
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error = 0;
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}
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}
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}
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return (error);
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}
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