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freebsd/sys/fs/procfs/procfs_regs.c
Mark Johnston 352aaa5122 Plug memory disclosures via ptrace(2).
On some architectures, the structures returned by PT_GET*REGS were not
fully populated and could contain uninitialized stack memory.  The same
issue existed with the register files in procfs.

Reported by:	Thomas Barabosch, Fraunhofer FKIE
Reviewed by:	kib
MFC after:	3 days
Security:	kernel stack memory disclosure
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D18421
2018-12-03 20:54:17 +00:00

134 lines
3.7 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1993 Jan-Simon Pendry
* Copyright (c) 1993
* The Regents of the University of California. 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. 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.
*
* @(#)procfs_regs.c 8.4 (Berkeley) 6/15/94
*
* From:
* $Id: procfs_regs.c,v 3.2 1993/12/15 09:40:17 jsp Exp $
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
#include <sys/sysent.h>
#include <sys/uio.h>
#include <machine/reg.h>
#include <fs/pseudofs/pseudofs.h>
#include <fs/procfs/procfs.h>
#ifdef COMPAT_FREEBSD32
#include <sys/procfs.h>
#include <machine/fpu.h>
/*
* PROC(write, regs, td2, &r) becomes
* proc_write_regs(td2, &r) or
* proc_write_regs32(td2, &r32)
*
* UIOMOVE_FROMBUF(r, uio) becomes
* uiomove_frombuf(&r, sizeof(r), uio) or
* uiomove_frombuf(&r32, sizeof(r32), uio)
*/
#define PROC(d, w, t, r) wrap32 ? \
proc_ ## d ## _ ## w ## 32(t, r ## 32) : \
proc_ ## d ## _ ## w(t, r)
#define UIOMOVE_FROMBUF(k, u) wrap32 ? \
uiomove_frombuf(& k ## 32, sizeof(k ## 32), u) : \
uiomove_frombuf(& k, sizeof(k), u)
#else
#define PROC(d, w, t, r) proc_ ## d ## _ ## w(t, r)
#define UIOMOVE_FROMBUF(k, u) uiomove_frombuf(& k, sizeof(k), u)
#endif
int
procfs_doprocregs(PFS_FILL_ARGS)
{
int error;
struct reg r;
struct thread *td2;
#ifdef COMPAT_FREEBSD32
struct reg32 r32;
int wrap32 = 0;
#endif
if (uio->uio_offset != 0)
return (0);
PROC_LOCK(p);
PROC_ASSERT_HELD(p);
if (p_candebug(td, p)) {
PROC_UNLOCK(p);
return (EPERM);
}
if (!P_SHOULDSTOP(p)) {
PROC_UNLOCK(p);
return (EBUSY);
}
td2 = FIRST_THREAD_IN_PROC(p);
#ifdef COMPAT_FREEBSD32
if (SV_CURPROC_FLAG(SV_ILP32)) {
if ((SV_PROC_FLAG(td2->td_proc, SV_ILP32)) == 0) {
PROC_UNLOCK(p);
return (EINVAL);
}
wrap32 = 1;
memset(&r32, 0, sizeof(r32));
} else
#endif
memset(&r, 0, sizeof(r));
error = PROC(read, regs, td2, &r);
if (error == 0) {
PROC_UNLOCK(p);
error = UIOMOVE_FROMBUF(r, uio);
PROC_LOCK(p);
}
if (error == 0 && uio->uio_rw == UIO_WRITE) {
if (!P_SHOULDSTOP(p))
error = EBUSY;
else
/* XXXKSE: */
error = PROC(write, regs, td2, &r);
}
PROC_UNLOCK(p);
return (error);
}