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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2017 Richard Palethorpe <rpalethorpe@suse.com>
*/
/* Test for CVE-2017-7308 on a raw socket's ring buffer
*
* Try to set tpacket_req3.tp_sizeof_priv to a value with the high bit set. So
* that tp_block_size < tp_sizeof_priv. If the vulnerability is present then
* this will cause an integer arithmetic overflow and the absurd
* tp_sizeof_priv value will be allowed. If it has been fixed then setsockopt
* will fail with EINVAL.
*
* We also try a good configuration to make sure it is not failing with EINVAL
* for some other reason.
*
* For a better and more interesting discussion of this CVE see:
* https://googleprojectzero.blogspot.com/2017/05/exploiting-linux-kernel-via-packet.html
*/
#include <errno.h>
#include "tst_test.h"
#include "tst_safe_net.h"
#include "lapi/if_packet.h"
#include "lapi/if_ether.h"
static int sk;
static long pgsz;
static void setup(void)
{
pgsz = SAFE_SYSCONF(_SC_PAGESIZE);
}
static void cleanup(void)
{
if (sk > 0)
SAFE_CLOSE(sk);
}
static int create_skbuf(unsigned int sizeof_priv)
{
int ver = TPACKET_V3;
struct tpacket_req3 req = {};
req.tp_block_size = pgsz;
req.tp_block_nr = 2;
req.tp_frame_size = req.tp_block_size;
req.tp_frame_nr = req.tp_block_nr;
req.tp_retire_blk_tov = 100;
req.tp_sizeof_priv = sizeof_priv;
sk = SAFE_SOCKET(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
TEST(setsockopt(sk, SOL_PACKET, PACKET_VERSION, &ver, sizeof(ver)));
if (TST_RET && TST_ERR == EINVAL)
tst_brk(TCONF | TTERRNO, "TPACKET_V3 not supported");
if (TST_RET)
tst_brk(TBROK | TTERRNO, "setsockopt(sk, SOL_PACKET, PACKET_VERSION, TPACKET_V3)");
return setsockopt(sk, SOL_PACKET, PACKET_RX_RING, &req, sizeof(req));
}
static void good_size(void)
{
TEST(create_skbuf(512));
if (TST_RET)
tst_brk(TBROK | TTERRNO, "Can't create ring buffer with good settings");
tst_res(TPASS, "Can create ring buffer with good settinegs");
}
static void bad_size(void)
{
TEST(create_skbuf(3U << 30));
if (TST_RET && TST_ERR != EINVAL)
tst_brk(TBROK | TTERRNO, "Unexpected setsockopt() error");
if (TST_RET)
tst_res(TPASS | TTERRNO, "Refused bad tp_sizeof_priv value");
else
tst_res(TFAIL, "Allowed bad tp_sizeof_priv value");
}
static void run(unsigned int i)
{
if (i == 0)
good_size();
else
bad_size();
SAFE_CLOSE(sk);
}
static struct tst_test test = {
.test = run,
.tcnt = 2,
.needs_root = 1,
.setup = setup,
.cleanup = cleanup,
};
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