Commit 6caf9efa authored by Michal Luczaj's avatar Michal Luczaj Committed by Daniel Borkmann
Browse files

selftests/bpf: Test sockmap redirect for AF_UNIX MSG_OOB 



Verify that out-of-band packets are silently dropped before they reach the
redirection logic.

The idea is to test with a 2 byte long send(). Should a MSG_OOB flag be in
use, only the last byte will be treated as out-of-band. Test fails if
verd_mapfd indicates a wrong number of packets processed (e.g. if OOB
wasn't dropped at the source) or if it was possible to recv() MSG_OOB from
the mapped socket, or if any stale OOB data have been left reachable from
the unmapped socket.

Signed-off-by: default avatarMichal Luczaj <mhal@rbox.co>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Tested-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Reviewed-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20240713200218.2140950-5-mhal@rbox.co
parent 0befb349

tools/testing/selftests/bpf/prog_tests/sockmap_listen.c

+33 −3
Original line number Diff line number Diff line
@@ -1399,10 +1399,11 @@ static void pairs_redir_to_connected(int cli0, int peer0, int cli1, int peer1, 
			return;

	}



	n = xsend(cli1, "a", 1, send_flags);

	if (n == 0)

	/* Last byte is OOB data when send_flags has MSG_OOB bit set */

	n = xsend(cli1, "ab", 2, send_flags);

	if (n >= 0 && n < 2)

		FAIL("%s: incomplete send", log_prefix);

	if (n < 1)

	if (n < 2)

		return;



	key = SK_PASS;
@@ -1417,6 +1418,25 @@ static void pairs_redir_to_connected(int cli0, int peer0, int cli1, int peer1, 
		FAIL_ERRNO("%s: recv_timeout", log_prefix);

	if (n == 0)

		FAIL("%s: incomplete recv", log_prefix);



	if (send_flags & MSG_OOB) {

		/* Check that we can't read OOB while in sockmap */

		errno = 0;

		n = recv(peer1, &b, 1, MSG_OOB | MSG_DONTWAIT);

		if (n != -1 || errno != EOPNOTSUPP)

			FAIL("%s: recv(MSG_OOB): expected EOPNOTSUPP: retval=%d errno=%d",

			     log_prefix, n, errno);



		/* Remove peer1 from sockmap */

		xbpf_map_delete_elem(sock_mapfd, &(int){ 1 });



		/* Check that OOB was dropped on redirect */

		errno = 0;

		n = recv(peer1, &b, 1, MSG_OOB | MSG_DONTWAIT);

		if (n != -1 || errno != EINVAL)

			FAIL("%s: recv(MSG_OOB): expected EINVAL: retval=%d errno=%d",

			     log_prefix, n, errno);

	}

}



static void unix_redir_to_connected(int sotype, int sock_mapfd,
@@ -1873,6 +1893,11 @@ static void unix_inet_skb_redir_to_connected(struct test_sockmap_listen *skel, 
				     sock_map, nop_map, verdict_map,

				     REDIR_EGRESS, NO_FLAGS);



	/* MSG_OOB not supported by AF_UNIX SOCK_DGRAM */

	unix_inet_redir_to_connected(family, SOCK_STREAM,

				     sock_map, nop_map, verdict_map,

				     REDIR_EGRESS, MSG_OOB);



	skel->bss->test_ingress = true;

	unix_inet_redir_to_connected(family, SOCK_DGRAM,

				     sock_map, -1, verdict_map,
@@ -1888,6 +1913,11 @@ static void unix_inet_skb_redir_to_connected(struct test_sockmap_listen *skel, 
				     sock_map, nop_map, verdict_map,

				     REDIR_INGRESS, NO_FLAGS);



	/* MSG_OOB not supported by AF_UNIX SOCK_DGRAM */

	unix_inet_redir_to_connected(family, SOCK_STREAM,

				     sock_map, nop_map, verdict_map,

				     REDIR_INGRESS, MSG_OOB);



	xbpf_prog_detach2(verdict, sock_map, BPF_SK_SKB_VERDICT);

}