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procfs_mem.c revision 1.27.2.3 
      1 /*	$NetBSD: procfs_mem.c,v 1.27.2.3 2002/02/28 04:14:57 nathanw Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1993 Jan-Simon Pendry
      5  * Copyright (c) 1993 Sean Eric Fagan
      6  * Copyright (c) 1993
      7  *	The Regents of the University of California.  All rights reserved.
      8  *
      9  * This code is derived from software contributed to Berkeley by
     10  * Jan-Simon Pendry and Sean Eric Fagan.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  *
     40  *	@(#)procfs_mem.c	8.5 (Berkeley) 6/15/94
     41  */
     42 
     43 /*
     44  * This is a lightly hacked and merged version
     45  * of sef's pread/pwrite functions
     46  */
     47 
     48 #include <sys/cdefs.h>
     49 __KERNEL_RCSID(0, "$NetBSD: procfs_mem.c,v 1.27.2.3 2002/02/28 04:14:57 nathanw Exp $");
     50 
     51 #include <sys/param.h>
     52 #include <sys/systm.h>
     53 #include <sys/time.h>
     54 #include <sys/kernel.h>
     55 #include <sys/lwp.h>
     56 #include <sys/proc.h>
     57 #include <sys/vnode.h>
     58 
     59 #include <miscfs/procfs/procfs.h>
     60 
     61 #include <uvm/uvm_extern.h>
     62 
     63 #define	ISSET(t, f)	((t) & (f))
     64 
     65 /*
     66  * Copy data in and out of the target process.
     67  * We do this by mapping the process's page into
     68  * the kernel and then doing a uiomove direct
     69  * from the kernel address space.
     70  */
     71 int
     72 procfs_domem(curp, l, pfs, uio)
     73 	struct proc *curp;		/* tracer */
     74 	struct lwp *l;			/* traced */
     75 	struct pfsnode *pfs;
     76 	struct uio *uio;
     77 {
     78 	int error;
     79 
     80 	size_t len;
     81 	struct proc *p = l->l_proc;
     82 #ifdef PMAP_NEED_PROCWR
     83 	vaddr_t	addr;
     84 #endif
     85 
     86 	len = uio->uio_resid;
     87 
     88 	if (len == 0)
     89 		return (0);
     90 
     91 #ifdef PMAP_NEED_PROCWR
     92 	addr = uio->uio_offset;
     93 #endif
     94 
     95 	if ((error = procfs_checkioperm(curp, p)) != 0)
     96 		return (error);
     97 
     98 	/* XXXCDC: how should locking work here? */
     99 	if ((p->p_flag & P_WEXIT) || (p->p_vmspace->vm_refcnt < 1))
    100 		return(EFAULT);
    101 	p->p_vmspace->vm_refcnt++;  /* XXX */
    102 	error = uvm_io(&p->p_vmspace->vm_map, uio);
    103 	uvmspace_free(p->p_vmspace);
    104 
    105 #ifdef PMAP_NEED_PROCWR
    106 	if (uio->uio_rw == UIO_WRITE)
    107 		pmap_procwr(p, addr, len);
    108 #endif
    109 	return (error);
    110 }
    111 
    112 /*
    113  * Ensure that a process has permission to perform I/O on another.
    114  * Arguments:
    115  *	p	The process wishing to do the I/O (the tracer).
    116  *	t	The process who's memory/registers will be read/written.
    117  */
    118 int
    119 procfs_checkioperm(p, t)
    120 	struct proc *p, *t;
    121 {
    122 	int error;
    123 
    124 	/*
    125 	 * You cannot attach to a processes mem/regs if:
    126 	 *
    127 	 *	(1) It is currently exec'ing
    128 	 */
    129 	if (ISSET(t->p_flag, P_INEXEC))
    130 		return (EAGAIN);
    131 
    132 	/*
    133 	 *	(2) it's not owned by you, or is set-id on exec
    134 	 *	    (unless you're root), or...
    135 	 */
    136 	if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
    137 		ISSET(t->p_flag, P_SUGID)) &&
    138 	    (error = suser(p->p_ucred, &p->p_acflag)) != 0)
    139 		return (error);
    140 
    141 	/*
    142 	 *	(3) ...it's init, which controls the security level
    143 	 *	    of the entire system, and the system was not
    144 	 *	    compiled with permanetly insecure mode turned on.
    145 	 */
    146 	if (t == initproc && securelevel > -1)
    147 		return (EPERM);
    148 
    149 	/*
    150 	 *	(4) the tracer is chrooted, and its root directory is
    151 	 * 	    not at or above the root directory of the tracee
    152 	 */
    153 	if (!proc_isunder(t, p))
    154 		return (EPERM);
    155 
    156 	return (0);
    157 }
    158