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Add the test program to examine CPU behaviour for pop ss issue

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CVE-2018-8897.

Requested by:	emaste
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
This commit is contained in:
Konstantin Belousov 2018-05-10 13:52:52 +00:00
parent d5cdcc3a06
commit 4072ae4e02
1 changed files with 183 additions and 0 deletions
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tools/test/popss/popss.c Normal file
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2018 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Konstantin Belousov <kib@FreeBSD.org>
* under sponsorship from the FreeBSD Foundation.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $Id: popss.c,v 1.28 2018/05/09 21:35:29 kostik Exp kostik $
* $FreeBSD$
*
* cc -m32 -Wall -Wextra -O2 -g -o popss popss.c
* Use as "popss <instruction>", where instruction is one of
* bound, into, int1, int3, int80, syscall, sysenter.
*/
#include <sys/param.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <err.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <machine/reg.h>
static u_long *stk;
#define ITERATIONS 4
static void
setup(pid_t child)
{
struct reg r;
struct dbreg dbr;
int error, i, status;
error = waitpid(child, &status, WTRAPPED | WEXITED);
if (error == -1)
err(1, "waitpid 1");
error = ptrace(PT_GETREGS, child, (caddr_t)&r, 0);
if (error == -1)
err(1, "ptrace PT_GETREGS");
printf("child %d stopped eip %#x esp %#x\n", child, r.r_eip, r.r_esp);
error = ptrace(PT_GETDBREGS, child, (caddr_t)&dbr, 0);
if (error != 0)
err(1, "ptrace PT_GETDBREGS");
dbr.dr[7] &= ~DBREG_DR7_MASK(0);
dbr.dr[7] |= DBREG_DR7_SET(0, DBREG_DR7_LEN_4, DBREG_DR7_RDWR,
DBREG_DR7_LOCAL_ENABLE | DBREG_DR7_GLOBAL_ENABLE);
dbr.dr[0] = (uintptr_t)stk;
error = ptrace(PT_SETDBREGS, child, (caddr_t)&dbr, 0);
if (error != 0)
err(1, "ptrace PT_SETDBREGS");
error = ptrace(PT_CONTINUE, child, (caddr_t)1, 0);
if (error != 0)
err(1, "ptrace PT_CONTINUE fire");
for (i = 0; i < ITERATIONS; i++) {
error = waitpid(child, &status, WTRAPPED | WEXITED);
if (error == -1)
err(1, "waitpid 2");
if (WIFEXITED(status))
break;
error = ptrace(PT_GETREGS, child, (caddr_t)&r, 0);
if (error == -1)
err(1, "ptrace PT_GETREGS");
error = ptrace(PT_GETDBREGS, child, (caddr_t)&dbr, 0);
if (error != 0)
err(1, "ptrace PT_GETDBREGS");
printf("child %d stopped eip %#x esp %#x dr0 %#x "
"dr6 %#x dr7 %#x\n", child, r.r_eip, r.r_esp,
dbr.dr[0], dbr.dr[6], dbr.dr[7]);
error = ptrace(PT_CONTINUE, child, (caddr_t)1, 0);
if (error == -1)
err(1, "ptrace PT_CONTINUE tail");
}
if (i == ITERATIONS) {
kill(child, SIGKILL);
ptrace(PT_DETACH, child, NULL, 0);
}
}
static u_long tmpstk[1024 * 128];
static u_int
read_ss(void)
{
u_int res;
__asm volatile("movl\t%%ss,%0" : "=r" (res));
return (res);
}
#define PROLOGUE "int3;movl\t%0,%%esp;popl\t%%ss;"
static void
act(const char *cmd)
{
int error;
static const int boundx[2] = {0, 1};
printf("child pid %d, stk at %p\n", getpid(), stk);
*stk = read_ss();
error = ptrace(PT_TRACE_ME, 0, NULL, 0);
if (error != 0)
err(1, "ptrace PT_TRACE_ME");
if (strcmp(cmd, "bound") == 0) {
/* XXX BOUND args order clang ias bug */
__asm volatile("int3;movl\t$11,%%eax;"
"movl\t%0,%%esp;popl\t%%ss;bound\t%1,%%eax"
: : "r" (stk), "m" (boundx) : "memory");
} else if (strcmp(cmd, "int1") == 0) {
__asm volatile(PROLOGUE ".byte 0xf1"
: : "r" (stk) : "memory");
} else if (strcmp(cmd, "int3") == 0) {
__asm volatile(PROLOGUE "int3"
: : "r" (stk) : "memory");
} else if (strcmp(cmd, "into") == 0) {
__asm volatile("int3;movl\t$0x80000000,%%eax;"
"addl\t%%eax,%%eax;movl\t%0,%%esp;popl\t%%ss;into"
: : "r" (stk) : "memory");
} else if (strcmp(cmd, "int80") == 0) {
__asm volatile(PROLOGUE "int\t$0x80"
: : "r" (stk) : "memory");
} else if (strcmp(cmd, "syscall") == 0) {
__asm volatile(PROLOGUE "syscall"
: : "r" (stk) : "memory");
} else if (strcmp(cmd, "sysenter") == 0) {
__asm volatile(PROLOGUE "sysenter"
: : "r" (stk) : "memory");
} else {
fprintf(stderr, "unknown instruction\n");
exit(1);
}
printf("ho\n");
}
int
main(int argc, char *argv[])
{
int child;
if (argc != 2) {
printf(
"Usage: popss [bound|int1|int3|into|int80|syscall|sysenter]\n");
exit(1);
}
stk = &tmpstk[nitems(tmpstk) - 1];
child = fork();
if (child == -1)
err(1, "fork");
if (child == 0)
act(argv[1]);
else
setup(child);
}