socket_accf.c

/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2022-2024 Gleb Smirnoff <[email protected]>
 *
 * 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/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>

#include <atf-c.h>

static int
listensock(struct sockaddr_in *sin)
{
	int l;

	ATF_REQUIRE((l = socket(PF_INET, SOCK_STREAM, 0)) > 0);
	ATF_REQUIRE(fcntl(l, F_SETFL, O_NONBLOCK) != -1);
	ATF_REQUIRE(setsockopt(l, SOL_SOCKET, SO_REUSEADDR, &(socklen_t){1},
	    sizeof(int)) == 0);
	*sin = (struct sockaddr_in){
		.sin_len = sizeof(sin),
		.sin_family = AF_INET,
		.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
	};
	ATF_REQUIRE(bind(l, (struct sockaddr *)sin, sizeof(*sin)) == 0);
	ATF_REQUIRE(getsockname(l, (struct sockaddr *)sin,
	    &(socklen_t){ sizeof(*sin) }) == 0);
	ATF_REQUIRE(listen(l, -1) == 0);

	return (l);
}

static int
clientsock(struct sockaddr_in *sin)
{
	int s;

	ATF_REQUIRE((s = socket(PF_INET, SOCK_STREAM, 0)) > 0);
	ATF_REQUIRE(connect(s, (struct sockaddr *)sin, sizeof(*sin)) == 0);

	return (s);
}

static void
accfon(int l, struct accept_filter_arg *af)
{
	if (setsockopt(l, SOL_SOCKET, SO_ACCEPTFILTER, af, sizeof(*af)) != 0) {
		atf_tc_fail("setsockopt(SO_ACCEPTFILTER): %s", strerror(errno));
	}
}

/*
 * XXX: return from send(2) on a localhost connection doesn't guarantee that
 * netisr has fully processed and delivered the data to the remote local
 * socket.  Sleep a fraction of second to "guarantee" that it did.
 */
static ssize_t
usend(int s, const void *msg, size_t len)
{
	ssize_t rv;

	rv = send(s, msg, len, 0);
	usleep(100000);
	return (rv);
}

ATF_TC(data);
ATF_TC_HEAD(data, tc)
{
	atf_tc_set_md_var(tc, "require.kmods", "accf_data");
}
ATF_TC_BODY(data, tc)
{
	struct accept_filter_arg afa = {
		.af_name = "dataready"
	};
	struct sockaddr_in sin;
	int l, s, a;

	l = listensock(&sin);
	accfon(l, &afa);
	s = clientsock(&sin);
	ATF_REQUIRE(accept(l, NULL, 0) == -1);
	ATF_REQUIRE(errno == EAGAIN);
	ATF_REQUIRE(usend(s, "foo", sizeof("foo")) == sizeof("foo"));
	ATF_REQUIRE((a = accept(l, NULL, 0)) > 0);
}

ATF_TC(http);
ATF_TC_HEAD(http, tc)
{
	atf_tc_set_md_var(tc, "require.kmods", "accf_http");
}
ATF_TC_BODY(http, tc)
{
	struct accept_filter_arg afa = {
		.af_name = "httpready"
	};
	struct sockaddr_in sin;
	int l, s, a;

	l = listensock(&sin);
	accfon(l, &afa);
	s = clientsock(&sin);

	/* 1) No data. */
	ATF_REQUIRE(accept(l, NULL, 0) == -1);
	ATF_REQUIRE(errno == EAGAIN);

	/* 2) Data, that doesn't look like HTTP. */
	ATF_REQUIRE(usend(s, "foo", sizeof("foo")) == sizeof("foo"));
	ATF_REQUIRE((a = accept(l, NULL, 0)) > 0);

	close(s);
	close(a);

#define	CHUNK1	"GET / "
#define	CHUNK2	"HTTP/1.0\r\n\n"
#define	LEN(c)	(sizeof(c) - 1)

	/* 3) Partial HTTP. */
	s = clientsock(&sin);
	ATF_REQUIRE(usend(s, CHUNK1, LEN(CHUNK1)) == LEN(CHUNK1));
	ATF_REQUIRE(accept(l, NULL, 0) == -1);
	ATF_REQUIRE(errno == EAGAIN);

	/* 4) Complete HTTP. */
	ATF_REQUIRE(usend(s, CHUNK2, LEN(CHUNK2)) == LEN(CHUNK2));
	ATF_REQUIRE((a = accept(l, NULL, 0)) > 0);
}

ATF_TC(tls);
ATF_TC_HEAD(tls, tc)
{
	atf_tc_set_md_var(tc, "require.kmods", "accf_tls");
}
ATF_TC_BODY(tls, tc)
{
	struct accept_filter_arg afa = {
		.af_name = "tlsready"
	};
	struct sockaddr_in sin;
	int l, s, a;

	l = listensock(&sin);
	accfon(l, &afa);
	s = clientsock(&sin);

	/* 1) No data. */
	ATF_REQUIRE(accept(l, NULL, 0) == -1);
	ATF_REQUIRE(errno == EAGAIN);

	/* 2) Less than 5 bytes. */
	ATF_REQUIRE(usend(s, "foo", sizeof("foo")) == sizeof("foo"));
	ATF_REQUIRE(errno == EAGAIN);

	/* 3) Something that doesn't look like TLS handshake. */
	ATF_REQUIRE(usend(s, "bar", sizeof("bar")) == sizeof("bar"));
	ATF_REQUIRE((a = accept(l, NULL, 0)) > 0);

	close(s);
	close(a);

	/* 4) Partial TLS record. */
	s = clientsock(&sin);
	struct {
		uint8_t  type;
		uint16_t version;
		uint16_t length;
	} __attribute__((__packed__)) header = {
		.type = 0x16,
		.length = htons((uint16_t)(arc4random() % 16384)),
	};
	_Static_assert(sizeof(header) == 5, "");
	ATF_REQUIRE(usend(s, &header, sizeof(header)) == sizeof(header));
	ssize_t sent = 0;
	do {
		size_t len;
		char *buf;

		ATF_REQUIRE(accept(l, NULL, 0) == -1);
		ATF_REQUIRE(errno == EAGAIN);

		len = arc4random() % 1024;
		buf = alloca(len);
		ATF_REQUIRE(usend(s, buf, len) == (ssize_t)len);
		sent += len;
	} while (sent < ntohs(header.length));
	/* TLS header with bytes >= declared length. */
	ATF_REQUIRE((a = accept(l, NULL, 0)) > 0);
}

/* Check changing to a different filter. */
ATF_TC(change);
ATF_TC_HEAD(change, tc)
{
	atf_tc_set_md_var(tc, "require.kmods", "accf_data accf_http");
}
ATF_TC_BODY(change, tc)
{
	struct accept_filter_arg dfa = {
		.af_name = "dataready"
	};
	struct accept_filter_arg hfa = {
		.af_name = "httpready"
	};
	struct sockaddr_in sin;
	int n, l;

	l = listensock(&sin);
	accfon(l, &dfa);

	/* Refuse to change filter without explicit removal of the old one. */
	ATF_REQUIRE(setsockopt(l, SOL_SOCKET, SO_ACCEPTFILTER, &hfa,
	    sizeof(hfa)) != 0 && errno == EBUSY);

	/* But allow after clearing. */
	ATF_REQUIRE(setsockopt(l, SOL_SOCKET, SO_ACCEPTFILTER, NULL, 0) == 0);
	ATF_REQUIRE(setsockopt(l, SOL_SOCKET, SO_ACCEPTFILTER, &hfa,
	    sizeof(hfa)) == 0);

	/* Must be listening socket. */
	ATF_REQUIRE((n = socket(PF_INET, SOCK_STREAM, 0)) > 0);
	ATF_REQUIRE(setsockopt(n, SOL_SOCKET, SO_ACCEPTFILTER, &dfa,
	    sizeof(dfa)) != 0 && errno == EINVAL);
}

ATF_TP_ADD_TCS(tp)
{
	ATF_TP_ADD_TC(tp, data);
	ATF_TP_ADD_TC(tp, http);
	ATF_TP_ADD_TC(tp, tls);
	ATF_TP_ADD_TC(tp, change);

	return (atf_no_error());
}