freebsd-dev/tests/sys/netinet/tcp_connect_port_test.c
Jonathan T. Looney 36c52a52ee Add a regression test for the port-selection behavior fixed in r367680.
Reviewed by:	markj, olivier, tuexen
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D27173
2020-11-14 15:44:28 +00:00

335 lines
9.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2020 Netflix, Inc.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <netinet/in.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <atf-c.h>
#define SYSCTLBAKFILE "tmp.net.inet.ip.portrange.randomized"
/*
* Check if port allocation is randomized. If so, update it. Save the old
* value of the sysctl so it can be updated later.
*/
static void
disable_random_ports(void)
{
int error, fd, random_new, random_save;
size_t sysctlsz;
/*
* Pre-emptively unlink our restoration file, so we will do no
* restoration on error.
*/
unlink(SYSCTLBAKFILE);
/*
* Disable the net.inet.ip.portrange.randomized sysctl. Save the
* old value so we can restore it, if necessary.
*/
random_new = 0;
sysctlsz = sizeof(random_save);
error = sysctlbyname("net.inet.ip.portrange.randomized", &random_save,
&sysctlsz, &random_new, sizeof(random_new));
if (error) {
warn("sysctlbyname(\"net.inet.ip.portrange.randomized\") "
"failed");
atf_tc_skip("Unable to set sysctl");
}
if (sysctlsz != sizeof(random_save)) {
fprintf(stderr, "Error: unexpected sysctl value size "
"(expected %zu, actual %zu)\n", sizeof(random_save),
sysctlsz);
goto restore_sysctl;
}
/* Open the backup file, write the contents, and close it. */
fd = open(SYSCTLBAKFILE, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL,
S_IRUSR|S_IWUSR);
if (fd < 0) {
warn("error opening sysctl backup file");
goto restore_sysctl;
}
error = write(fd, &random_save, sizeof(random_save));
if (error < 0) {
warn("error writing saved value to sysctl backup file");
goto cleanup_and_restore;
}
if (error != (int)sizeof(random_save)) {
fprintf(stderr,
"Error writing saved value to sysctl backup file: "
"(expected %zu, actual %d)\n", sizeof(random_save), error);
goto cleanup_and_restore;
}
error = close(fd);
if (error) {
warn("error closing sysctl backup file");
cleanup_and_restore:
(void)close(fd);
(void)unlink(SYSCTLBAKFILE);
restore_sysctl:
(void)sysctlbyname("net.inet.ip.portrange.randomized", NULL,
NULL, &random_save, sysctlsz);
atf_tc_skip("Error setting sysctl");
}
}
/*
* Restore the sysctl value from the backup file and delete the backup file.
*/
static void
restore_random_ports(void)
{
int error, fd, random_save;
/* Open the backup file, read the contents, close it, and delete it. */
fd = open(SYSCTLBAKFILE, O_RDONLY);
if (fd < 0) {
warn("error opening sysctl backup file");
return;
}
error = read(fd, &random_save, sizeof(random_save));
if (error < 0) {
warn("error reading saved value from sysctl backup file");
return;
}
if (error != (int)sizeof(random_save)) {
fprintf(stderr,
"Error reading saved value from sysctl backup file: "
"(expected %zu, actual %d)\n", sizeof(random_save), error);
return;
}
error = close(fd);
if (error)
warn("error closing sysctl backup file");
error = unlink(SYSCTLBAKFILE);
if (error)
warn("error removing sysctl backup file");
/* Restore the saved sysctl value. */
error = sysctlbyname("net.inet.ip.portrange.randomized", NULL, NULL,
&random_save, sizeof(random_save));
if (error)
warn("sysctlbyname(\"net.inet.ip.portrange.randomized\") "
"failed while restoring value");
}
/*
* Given a domain and sockaddr, open a listening socket with automatic port
* selection. Then, try to connect 64K times. Ensure the connected socket never
* uses an overlapping port.
*/
static void
connect_loop(int domain, const struct sockaddr *addr)
{
union {
struct sockaddr saddr;
struct sockaddr_in saddr4;
struct sockaddr_in6 saddr6;
} su_clnt, su_srvr;
socklen_t salen;
int asock, csock, error, i, lsock;
const struct linger lopt = { 1, 0 };
/*
* Disable the net.inet.ip.portrange.randomized sysctl. Assuming an
* otherwise idle system, this makes the kernel try all possible
* ports sequentially and makes it more likely it will try the
* port on which we have a listening socket.
*/
disable_random_ports();
/* Setup the listen socket. */
lsock = socket(domain, SOCK_STREAM, 0);
ATF_REQUIRE_MSG(lsock >= 0, "socket() for listen socket failed: %s",
strerror(errno));
error = bind(lsock, addr, addr->sa_len);
ATF_REQUIRE_MSG(error == 0, "bind() failed: %s", strerror(errno));
error = listen(lsock, 1);
ATF_REQUIRE_MSG(error == 0, "listen() failed: %s", strerror(errno));
/*
* Get the address of the listen socket, which will be the destination
* address for our connection attempts.
*/
salen = sizeof(su_srvr);
error = getsockname(lsock, &su_srvr.saddr, &salen);
ATF_REQUIRE_MSG(error == 0,
"getsockname() for listen socket failed: %s",
strerror(errno));
ATF_REQUIRE_MSG(salen == (domain == PF_INET ?
sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)),
"unexpected sockaddr size");
ATF_REQUIRE_MSG(su_srvr.saddr.sa_len == (domain == PF_INET ?
sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)),
"unexpected sa_len size");
/* Open 64K connections in a loop. */
for (i = 0; i < 65536; i++) {
csock = socket(domain, SOCK_STREAM, 0);
ATF_REQUIRE_MSG(csock >= 0,
"socket() for client socket %d failed: %s",
i, strerror(errno));
error = connect(csock, &su_srvr.saddr, su_srvr.saddr.sa_len);
ATF_REQUIRE_MSG(error == 0,
"connect() for client socket %d failed: %s",
i, strerror(errno));
error = setsockopt(csock, SOL_SOCKET, SO_LINGER, &lopt,
sizeof(lopt));
ATF_REQUIRE_MSG(error == 0,
"Setting linger for client socket %d failed: %s",
i, strerror(errno));
/* Ascertain the client socket address. */
salen = sizeof(su_clnt);
error = getsockname(csock, &su_clnt.saddr, &salen);
ATF_REQUIRE_MSG(error == 0,
"getsockname() for client socket %d failed: %s",
i, strerror(errno));
ATF_REQUIRE_MSG(salen == (domain == PF_INET ?
sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)),
"unexpected sockaddr size for client socket %d", i);
/* Ensure the ports do not match. */
switch (domain) {
case PF_INET:
ATF_REQUIRE_MSG(su_clnt.saddr4.sin_port !=
su_srvr.saddr4.sin_port,
"client socket %d using the same port as server",
i);
break;
case PF_INET6:
ATF_REQUIRE_MSG(su_clnt.saddr6.sin6_port !=
su_srvr.saddr6.sin6_port,
"client socket %d using the same port as server",
i);
break;
}
/* Accept the socket and close both ends. */
asock = accept(lsock, NULL, NULL);
ATF_REQUIRE_MSG(asock >= 0,
"accept() failed for client socket %d: %s",
i, strerror(errno));
error = close(asock);
ATF_REQUIRE_MSG(error == 0,
"close() failed for accepted socket %d: %s",
i, strerror(errno));
error = close(csock);
ATF_REQUIRE_MSG(error == 0,
"close() failed for client socket %d: %s",
i, strerror(errno));
}
}
ATF_TC_WITH_CLEANUP(basic_ipv4);
ATF_TC_HEAD(basic_ipv4, tc)
{
atf_tc_set_md_var(tc, "require.user", "root");
atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
atf_tc_set_md_var(tc, "descr",
"Check automatic local port assignment during TCP connect calls");
}
ATF_TC_BODY(basic_ipv4, tc)
{
struct sockaddr_in saddr4;
memset(&saddr4, 0, sizeof(saddr4));
saddr4.sin_len = sizeof(saddr4);
saddr4.sin_family = AF_INET;
saddr4.sin_port = htons(0);
saddr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
connect_loop(PF_INET, (const struct sockaddr *)&saddr4);
}
ATF_TC_CLEANUP(basic_ipv4, tc)
{
restore_random_ports();
}
ATF_TC_WITH_CLEANUP(basic_ipv6);
ATF_TC_HEAD(basic_ipv6, tc)
{
atf_tc_set_md_var(tc, "require.user", "root");
atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
atf_tc_set_md_var(tc, "descr",
"Check automatic local port assignment during TCP connect calls");
}
ATF_TC_BODY(basic_ipv6, tc)
{
struct sockaddr_in6 saddr6;
memset(&saddr6, 0, sizeof(saddr6));
saddr6.sin6_len = sizeof(saddr6);
saddr6.sin6_family = AF_INET6;
saddr6.sin6_port = htons(0);
saddr6.sin6_addr = in6addr_loopback;
connect_loop(PF_INET6, (const struct sockaddr *)&saddr6);
}
ATF_TC_CLEANUP(basic_ipv6, tc)
{
restore_random_ports();
}
ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, basic_ipv4);
ATF_TP_ADD_TC(tp, basic_ipv6);
return (atf_no_error());
}