Merge branch 'af_unix-fix-bunch-of-msg_oob-bugs-and-add-new-tests'

Kuniyuki Iwashima says:

====================
af_unix: Fix bunch of MSG_OOB bugs and add new tests.

This series rewrites the selftest for AF_UNIX MSG_OOB and fixes
bunch of bugs that AF_UNIX behaves differently compared to TCP.

Note that the test discovered few more bugs in TCP side, which
will be fixed in another series.
====================

Link: https://lore.kernel.org/r/20240625013645.45034-1-kuniyu@amazon.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

net/unix/af_unix.c

@@ -2613,10 +2613,24 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 {
 	struct unix_sock *u = unix_sk(sk);
 
-	if (!unix_skb_len(skb) && !(flags & MSG_PEEK)) {
-		skb_unlink(skb, &sk->sk_receive_queue);
-		consume_skb(skb);
-		skb = NULL;
+	if (!unix_skb_len(skb)) {
+		struct sk_buff *unlinked_skb = NULL;
+
+		spin_lock(&sk->sk_receive_queue.lock);
+
+		if (copied && (!u->oob_skb || skb == u->oob_skb)) {
+			skb = NULL;
+		} else if (flags & MSG_PEEK) {
+			skb = skb_peek_next(skb, &sk->sk_receive_queue);
+		} else {
+			unlinked_skb = skb;
+			skb = skb_peek_next(skb, &sk->sk_receive_queue);
+			__skb_unlink(unlinked_skb, &sk->sk_receive_queue);
+		}
+
+		spin_unlock(&sk->sk_receive_queue.lock);
+
+		consume_skb(unlinked_skb);
 	} else {
 		struct sk_buff *unlinked_skb = NULL;
 
@@ -3093,12 +3107,23 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 #if IS_ENABLED(CONFIG_AF_UNIX_OOB)
 	case SIOCATMARK:
 		{
+			struct unix_sock *u = unix_sk(sk);
 			struct sk_buff *skb;
 			int answ = 0;
 
+			mutex_lock(&u->iolock);
+
 			skb = skb_peek(&sk->sk_receive_queue);
-			if (skb && skb == READ_ONCE(unix_sk(sk)->oob_skb))
-				answ = 1;
+			if (skb) {
+				struct sk_buff *oob_skb = READ_ONCE(u->oob_skb);
+
+				if (skb == oob_skb ||
+				    (!oob_skb && !unix_skb_len(skb)))
+					answ = 1;
+			}
+
+			mutex_unlock(&u->iolock);
+
 			err = put_user(answ, (int __user *)arg);
 		}
 		break;

tools/testing/selftests/net/.gitignore

@@ -43,7 +43,6 @@ tap
 tcp_fastopen_backup_key
 tcp_inq
 tcp_mmap
-test_unix_oob
 timestamping
 tls
 toeplitz

tools/testing/selftests/net/af_unix/Makefile

 CFLAGS += $(KHDR_INCLUDES)
-TEST_GEN_PROGS := diag_uid test_unix_oob unix_connect scm_pidfd scm_rights
+TEST_GEN_PROGS := diag_uid msg_oob scm_pidfd scm_rights unix_connect
 
 include ../../lib.mk

tools/testing/selftests/net/af_unix/msg_oob.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright Amazon.com Inc. or its affiliates. */
+
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <netinet/in.h>
+#include <sys/epoll.h>
+#include <sys/ioctl.h>
+#include <sys/signalfd.h>
+#include <sys/socket.h>
+
+#include "../../kselftest_harness.h"
+
+#define BUF_SZ	32
+
+FIXTURE(msg_oob)
+{
+	int fd[4];		/* 0: AF_UNIX sender
+				 * 1: AF_UNIX receiver
+				 * 2: TCP sender
+				 * 3: TCP receiver
+				 */
+	int signal_fd;
+	int epoll_fd[2];	/* 0: AF_UNIX receiver
+				 * 1: TCP receiver
+				 */
+	bool tcp_compliant;
+};
+
+FIXTURE_VARIANT(msg_oob)
+{
+	bool peek;
+};
+
+FIXTURE_VARIANT_ADD(msg_oob, no_peek)
+{
+	.peek = false,
+};
+
+FIXTURE_VARIANT_ADD(msg_oob, peek)
+{
+	.peek = true
+};
+
+static void create_unix_socketpair(struct __test_metadata *_metadata,
+				   FIXTURE_DATA(msg_oob) *self)
+{
+	int ret;
+
+	ret = socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0, self->fd);
+	ASSERT_EQ(ret, 0);
+}
+
+static void create_tcp_socketpair(struct __test_metadata *_metadata,
+				  FIXTURE_DATA(msg_oob) *self)
+{
+	struct sockaddr_in addr;
+	socklen_t addrlen;
+	int listen_fd;
+	int ret;
+
+	listen_fd = socket(AF_INET, SOCK_STREAM, 0);
+	ASSERT_GE(listen_fd, 0);
+
+	ret = listen(listen_fd, -1);
+	ASSERT_EQ(ret, 0);
+
+	addrlen = sizeof(addr);
+	ret = getsockname(listen_fd, (struct sockaddr *)&addr, &addrlen);
+	ASSERT_EQ(ret, 0);
+
+	self->fd[2] = socket(AF_INET, SOCK_STREAM, 0);
+	ASSERT_GE(self->fd[2], 0);
+
+	ret = connect(self->fd[2], (struct sockaddr *)&addr, addrlen);
+	ASSERT_EQ(ret, 0);
+
+	self->fd[3] = accept(listen_fd, (struct sockaddr *)&addr, &addrlen);
+	ASSERT_GE(self->fd[3], 0);
+
+	ret = fcntl(self->fd[3], F_SETFL, O_NONBLOCK);
+	ASSERT_EQ(ret, 0);
+}
+
+static void setup_sigurg(struct __test_metadata *_metadata,
+			 FIXTURE_DATA(msg_oob) *self)
+{
+	struct signalfd_siginfo siginfo;
+	int pid = getpid();
+	sigset_t mask;
+	int i, ret;
+
+	for (i = 0; i < 2; i++) {
+		ret = ioctl(self->fd[i * 2 + 1], FIOSETOWN, &pid);
+		ASSERT_EQ(ret, 0);
+	}
+
+	ret = sigemptyset(&mask);
+	ASSERT_EQ(ret, 0);
+
+	ret = sigaddset(&mask, SIGURG);
+	ASSERT_EQ(ret, 0);
+
+	ret = sigprocmask(SIG_BLOCK, &mask, NULL);
+	ASSERT_EQ(ret, 0);
+
+	self->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK);
+	ASSERT_GE(self->signal_fd, 0);
+
+	ret = read(self->signal_fd, &siginfo, sizeof(siginfo));
+	ASSERT_EQ(ret, -1);
+}
+
+static void setup_epollpri(struct __test_metadata *_metadata,
+			   FIXTURE_DATA(msg_oob) *self)
+{
+	struct epoll_event event = {
+		.events = EPOLLPRI,
+	};
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		int ret;
+
+		self->epoll_fd[i] = epoll_create1(0);
+		ASSERT_GE(self->epoll_fd[i], 0);
+
+		ret = epoll_ctl(self->epoll_fd[i], EPOLL_CTL_ADD, self->fd[i * 2 + 1], &event);
+		ASSERT_EQ(ret, 0);
+	}
+}
+
+static void close_sockets(FIXTURE_DATA(msg_oob) *self)
+{
+	int i;
+
+	for (i = 0; i < 4; i++)
+		close(self->fd[i]);
+}
+
+FIXTURE_SETUP(msg_oob)
+{
+	create_unix_socketpair(_metadata, self);
+	create_tcp_socketpair(_metadata, self);
+
+	setup_sigurg(_metadata, self);
+	setup_epollpri(_metadata, self);
+
+	self->tcp_compliant = true;
+}
+
+FIXTURE_TEARDOWN(msg_oob)
+{
+	close_sockets(self);
+}
+
+static void __epollpair(struct __test_metadata *_metadata,
+			FIXTURE_DATA(msg_oob) *self,
+			bool oob_remaining)
+{
+	struct epoll_event event[2] = {};
+	int i, ret[2];
+
+	for (i = 0; i < 2; i++)
+		ret[i] = epoll_wait(self->epoll_fd[i], &event[i], 1, 0);
+
+	ASSERT_EQ(ret[0], oob_remaining);
+
+	if (self->tcp_compliant)
+		ASSERT_EQ(ret[0], ret[1]);
+
+	if (oob_remaining) {
+		ASSERT_EQ(event[0].events, EPOLLPRI);
+
+		if (self->tcp_compliant)
+			ASSERT_EQ(event[0].events, event[1].events);
+	}
+}
+
+static void __sendpair(struct __test_metadata *_metadata,
+		       FIXTURE_DATA(msg_oob) *self,
+		       const void *buf, size_t len, int flags)
+{
+	int i, ret[2];
+
+	for (i = 0; i < 2; i++) {
+		struct signalfd_siginfo siginfo = {};
+		int bytes;
+
+		ret[i] = send(self->fd[i * 2], buf, len, flags);
+
+		bytes = read(self->signal_fd, &siginfo, sizeof(siginfo));
+
+		if (flags & MSG_OOB) {
+			ASSERT_EQ(bytes, sizeof(siginfo));
+			ASSERT_EQ(siginfo.ssi_signo, SIGURG);
+
+			bytes = read(self->signal_fd, &siginfo, sizeof(siginfo));
+		}
+
+		ASSERT_EQ(bytes, -1);
+	}
+
+	ASSERT_EQ(ret[0], len);
+	ASSERT_EQ(ret[0], ret[1]);
+}
+
+static void __recvpair(struct __test_metadata *_metadata,
+		       FIXTURE_DATA(msg_oob) *self,
+		       const void *expected_buf, int expected_len,
+		       int buf_len, int flags)
+{
+	int i, ret[2], recv_errno[2], expected_errno = 0;
+	char recv_buf[2][BUF_SZ] = {};
+	bool printed = false;
+
+	ASSERT_GE(BUF_SZ, buf_len);
+
+	errno = 0;
+
+	for (i = 0; i < 2; i++) {
+		ret[i] = recv(self->fd[i * 2 + 1], recv_buf[i], buf_len, flags);
+		recv_errno[i] = errno;
+	}
+
+	if (expected_len < 0) {
+		expected_errno = -expected_len;
+		expected_len = -1;
+	}
+
+	if (ret[0] != expected_len || recv_errno[0] != expected_errno) {
+		TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]);
+		TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf);
+
+		ASSERT_EQ(ret[0], expected_len);
+		ASSERT_EQ(recv_errno[0], expected_errno);
+	}
+
+	if (ret[0] != ret[1] || recv_errno[0] != recv_errno[1]) {
+		TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]);
+		TH_LOG("TCP     :%s", ret[1] < 0 ? strerror(recv_errno[1]) : recv_buf[1]);
+
+		printed = true;
+
+		if (self->tcp_compliant) {
+			ASSERT_EQ(ret[0], ret[1]);
+			ASSERT_EQ(recv_errno[0], recv_errno[1]);
+		}
+	}
+
+	if (expected_len >= 0) {
+		int cmp;
+
+		cmp = strncmp(expected_buf, recv_buf[0], expected_len);
+		if (cmp) {
+			TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]);
+			TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf);
+
+			ASSERT_EQ(cmp, 0);
+		}
+
+		cmp = strncmp(recv_buf[0], recv_buf[1], expected_len);
+		if (cmp) {
+			if (!printed) {
+				TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]);
+				TH_LOG("TCP     :%s", ret[1] < 0 ? strerror(recv_errno[1]) : recv_buf[1]);
+			}
+
+			if (self->tcp_compliant)
+				ASSERT_EQ(cmp, 0);
+		}
+	}
+}
+
+static void __setinlinepair(struct __test_metadata *_metadata,
+			    FIXTURE_DATA(msg_oob) *self)
+{
+	int i, oob_inline = 1;
+
+	for (i = 0; i < 2; i++) {
+		int ret;
+
+		ret = setsockopt(self->fd[i * 2 + 1], SOL_SOCKET, SO_OOBINLINE,
+				 &oob_inline, sizeof(oob_inline));
+		ASSERT_EQ(ret, 0);
+	}
+}
+
+static void __siocatmarkpair(struct __test_metadata *_metadata,
+			     FIXTURE_DATA(msg_oob) *self,
+			     bool oob_head)
+{
+	int answ[2] = {};
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		int ret;
+
+		ret = ioctl(self->fd[i * 2 + 1], SIOCATMARK, &answ[i]);
+		ASSERT_EQ(ret, 0);
+	}
+
+	ASSERT_EQ(answ[0], oob_head);
+
+	if (self->tcp_compliant)
+		ASSERT_EQ(answ[0], answ[1]);
+}
+
+#define sendpair(buf, len, flags)					\
+	__sendpair(_metadata, self, buf, len, flags)
+
+#define recvpair(expected_buf, expected_len, buf_len, flags)		\
+	do {								\
+		if (variant->peek)					\
+			__recvpair(_metadata, self,			\
+				   expected_buf, expected_len,		\
+				   buf_len, (flags) | MSG_PEEK);	\
+		__recvpair(_metadata, self,				\
+			   expected_buf, expected_len, buf_len, flags);	\
+	} while (0)
+
+#define epollpair(oob_remaining)					\
+	__epollpair(_metadata, self, oob_remaining)
+
+#define siocatmarkpair(oob_head)					\
+	__siocatmarkpair(_metadata, self, oob_head)
+
+#define setinlinepair()							\
+	__setinlinepair(_metadata, self)
+
+#define tcp_incompliant							\
+	for (self->tcp_compliant = false;				\
+	     self->tcp_compliant == false;				\
+	     self->tcp_compliant = true)
+
+TEST_F(msg_oob, non_oob)
+{
+	sendpair("x", 1, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	recvpair("", -EINVAL, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, oob)
+{
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("x", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(true);
+}
+
+TEST_F(msg_oob, oob_drop)
+{
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("", -EAGAIN, 1, 0);		/* Drop OOB. */
+	epollpair(false);
+	siocatmarkpair(false);
+
+	recvpair("", -EINVAL, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, oob_ahead)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("o", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 4, 0);
+	epollpair(false);
+	siocatmarkpair(true);
+}
+
+TEST_F(msg_oob, oob_break)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 5, 0);		/* Break at OOB even with enough buffer. */
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("o", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(true);
+
+	recvpair("", -EAGAIN, 1, 0);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, oob_ahead_break)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("world", 5, 0);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("o", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 9, 0);		/* Break at OOB even after it's recv()ed. */
+	epollpair(false);
+	siocatmarkpair(true);
+
+	recvpair("world", 5, 5, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, oob_break_drop)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("world", 5, 0);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 10, 0);		/* Break at OOB even with enough buffer. */
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("world", 5, 10, 0);		/* Drop OOB and recv() the next skb. */
+	epollpair(false);
+	siocatmarkpair(false);
+
+	recvpair("", -EINVAL, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, ex_oob_break)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("wor", 3, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("ld", 2, 0);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("hellowo", 7, 10, 0);		/* Break at OOB but not at ex-OOB. */
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("r", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(true);
+
+	recvpair("ld", 2, 2, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, ex_oob_drop)
+{
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	sendpair("y", 1, MSG_OOB);		/* TCP drops "x" at this moment. */
+	epollpair(true);
+
+	tcp_incompliant {
+		siocatmarkpair(false);
+
+		recvpair("x", 1, 1, 0);		/* TCP drops "y" by passing through it. */
+		epollpair(true);
+		siocatmarkpair(true);
+
+		recvpair("y", 1, 1, MSG_OOB);	/* TCP returns -EINVAL. */
+		epollpair(false);
+		siocatmarkpair(true);
+	}
+}
+
+TEST_F(msg_oob, ex_oob_drop_2)
+{
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	sendpair("y", 1, MSG_OOB);		/* TCP drops "x" at this moment. */
+	epollpair(true);
+
+	tcp_incompliant {
+		siocatmarkpair(false);
+	}
+
+	recvpair("y", 1, 1, MSG_OOB);
+	epollpair(false);
+
+	tcp_incompliant {
+		siocatmarkpair(false);
+
+		recvpair("x", 1, 1, 0);		/* TCP returns -EAGAIN. */
+		epollpair(false);
+		siocatmarkpair(true);
+	}
+}
+
+TEST_F(msg_oob, ex_oob_ahead_break)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("wor", 3, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("r", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	sendpair("ld", 2, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	tcp_incompliant {
+		recvpair("hellowol", 8, 10, 0);	/* TCP recv()s "helloworl", why "r" ?? */
+	}
+
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("d", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(true);
+}
+
+TEST_F(msg_oob, ex_oob_siocatmark)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("o", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	sendpair("world", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 4, 0);		/* Intentionally stop at ex-OOB. */
+	epollpair(true);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, inline_oob)
+{
+	setinlinepair();
+
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("", -EINVAL, 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("x", 1, 1, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, inline_oob_break)
+{
+	setinlinepair();
+
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("", -EINVAL, 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 5, 0);		/* Break at OOB but not at ex-OOB. */
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("o", 1, 1, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, inline_oob_ahead_break)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("world", 5, 0);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("o", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	setinlinepair();
+
+	recvpair("hell", 4, 9, 0);		/* Break at OOB even with enough buffer. */
+	epollpair(false);
+	siocatmarkpair(true);
+
+	tcp_incompliant {
+		recvpair("world", 5, 6, 0);	/* TCP recv()s "oworld", ... "o" ??? */
+	}
+
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, inline_ex_oob_break)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("wor", 3, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	sendpair("ld", 2, 0);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	setinlinepair();
+
+	recvpair("hellowo", 7, 10, 0);		/* Break at OOB but not at ex-OOB. */
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("rld", 3, 3, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, inline_ex_oob_no_drop)
+{
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	setinlinepair();
+
+	sendpair("y", 1, MSG_OOB);		/* TCP does NOT drops "x" at this moment. */
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("x", 1, 1, 0);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	recvpair("y", 1, 1, 0);
+	epollpair(false);
+	siocatmarkpair(false);
+}
+
+TEST_F(msg_oob, inline_ex_oob_drop)
+{
+	sendpair("x", 1, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(true);
+
+	sendpair("y", 1, MSG_OOB);		/* TCP drops "x" at this moment. */
+	epollpair(true);
+
+	setinlinepair();
+
+	tcp_incompliant {
+		siocatmarkpair(false);
+
+		recvpair("x", 1, 1, 0);		/* TCP recv()s "y". */
+		epollpair(true);
+		siocatmarkpair(true);
+
+		recvpair("y", 1, 1, 0);		/* TCP returns -EAGAIN. */
+		epollpair(false);
+		siocatmarkpair(false);
+	}
+}
+
+TEST_F(msg_oob, inline_ex_oob_siocatmark)
+{
+	sendpair("hello", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("o", 1, 1, MSG_OOB);
+	epollpair(false);
+	siocatmarkpair(false);
+
+	setinlinepair();
+
+	sendpair("world", 5, MSG_OOB);
+	epollpair(true);
+	siocatmarkpair(false);
+
+	recvpair("hell", 4, 4, 0);		/* Intentionally stop at ex-OOB. */
+	epollpair(true);
+	siocatmarkpair(false);
+}
+
+TEST_HARNESS_MAIN

tools/testing/selftests/net/af_unix/test_unix_oob.c

-// SPDX-License-Identifier: GPL-2.0-or-later
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <unistd.h>
-#include <string.h>
-#include <fcntl.h>
-#include <sys/ioctl.h>
-#include <errno.h>
-#include <netinet/tcp.h>
-#include <sys/un.h>
-#include <sys/signal.h>
-#include <sys/poll.h>
-
-static int pipefd[2];
-static int signal_recvd;
-static pid_t producer_id;
-static char sock_name[32];
-
-static void sig_hand(int sn, siginfo_t *si, void *p)
-{
-	signal_recvd = sn;
-}
-
-static int set_sig_handler(int signal)
-{
-	struct sigaction sa;
-
-	sa.sa_sigaction = sig_hand;
-	sigemptyset(&sa.sa_mask);
-	sa.sa_flags = SA_SIGINFO | SA_RESTART;
-
-	return sigaction(signal, &sa, NULL);
-}
-
-static void set_filemode(int fd, int set)
-{
-	int flags = fcntl(fd, F_GETFL, 0);
-
-	if (set)
-		flags &= ~O_NONBLOCK;
-	else
-		flags |= O_NONBLOCK;
-	fcntl(fd, F_SETFL, flags);
-}
-
-static void signal_producer(int fd)
-{
-	char cmd;
-
-	cmd = 'S';
-	write(fd, &cmd, sizeof(cmd));
-}
-
-static void wait_for_signal(int fd)
-{
-	char buf[5];
-
-	read(fd, buf, 5);
-}
-
-static void die(int status)
-{
-	fflush(NULL);
-	unlink(sock_name);
-	kill(producer_id, SIGTERM);
-	exit(status);
-}
-
-int is_sioctatmark(int fd)
-{
-	int ans = -1;
-
-	if (ioctl(fd, SIOCATMARK, &ans, sizeof(ans)) < 0) {
-#ifdef DEBUG
-		perror("SIOCATMARK Failed");
-#endif
-	}
-	return ans;
-}
-
-void read_oob(int fd, char *c)
-{
-
-	*c = ' ';
-	if (recv(fd, c, sizeof(*c), MSG_OOB) < 0) {
-#ifdef DEBUG
-		perror("Reading MSG_OOB Failed");
-#endif
-	}
-}
-
-int read_data(int pfd, char *buf, int size)
-{
-	int len = 0;
-
-	memset(buf, size, '0');
-	len = read(pfd, buf, size);
-#ifdef DEBUG
-	if (len < 0)
-		perror("read failed");
-#endif
-	return len;
-}
-
-static void wait_for_data(int pfd, int event)
-{
-	struct pollfd pfds[1];
-
-	pfds[0].fd = pfd;
-	pfds[0].events = event;
-	poll(pfds, 1, -1);
-}
-
-void producer(struct sockaddr_un *consumer_addr)
-{
-	int cfd;
-	char buf[64];
-	int i;
-
-	memset(buf, 'x', sizeof(buf));
-	cfd = socket(AF_UNIX, SOCK_STREAM, 0);
-
-	wait_for_signal(pipefd[0]);
-	if (connect(cfd, (struct sockaddr *)consumer_addr,
-		     sizeof(*consumer_addr)) != 0) {
-		perror("Connect failed");
-		kill(0, SIGTERM);
-		exit(1);
-	}
-
-	for (i = 0; i < 2; i++) {
-		/* Test 1: Test for SIGURG and OOB */
-		wait_for_signal(pipefd[0]);
-		memset(buf, 'x', sizeof(buf));
-		buf[63] = '@';
-		send(cfd, buf, sizeof(buf), MSG_OOB);
-
-		wait_for_signal(pipefd[0]);
-
-		/* Test 2: Test for OOB being overwitten */
-		memset(buf, 'x', sizeof(buf));
-		buf[63] = '%';
-		send(cfd, buf, sizeof(buf), MSG_OOB);
-
-		memset(buf, 'x', sizeof(buf));
-		buf[63] = '#';
-		send(cfd, buf, sizeof(buf), MSG_OOB);
-
-		wait_for_signal(pipefd[0]);
-
-		/* Test 3: Test for SIOCATMARK */
-		memset(buf, 'x', sizeof(buf));
-		buf[63] = '@';
-		send(cfd, buf, sizeof(buf), MSG_OOB);
-
-		memset(buf, 'x', sizeof(buf));
-		buf[63] = '%';
-		send(cfd, buf, sizeof(buf), MSG_OOB);
-
-		memset(buf, 'x', sizeof(buf));
-		send(cfd, buf, sizeof(buf), 0);
-
-		wait_for_signal(pipefd[0]);
-
-		/* Test 4: Test for 1byte OOB msg */
-		memset(buf, 'x', sizeof(buf));
-		buf[0] = '@';
-		send(cfd, buf, 1, MSG_OOB);
-	}
-}
-
-int
-main(int argc, char **argv)
-{
-	int lfd, pfd;
-	struct sockaddr_un consumer_addr, paddr;
-	socklen_t len = sizeof(consumer_addr);
-	char buf[1024];
-	int on = 0;
-	char oob;
-	int atmark;
-
-	lfd = socket(AF_UNIX, SOCK_STREAM, 0);
-	memset(&consumer_addr, 0, sizeof(consumer_addr));
-	consumer_addr.sun_family = AF_UNIX;
-	sprintf(sock_name, "unix_oob_%d", getpid());
-	unlink(sock_name);
-	strcpy(consumer_addr.sun_path, sock_name);
-
-	if ((bind(lfd, (struct sockaddr *)&consumer_addr,
-		  sizeof(consumer_addr))) != 0) {
-		perror("socket bind failed");
-		exit(1);
-	}
-
-	pipe(pipefd);
-
-	listen(lfd, 1);
-
-	producer_id = fork();
-	if (producer_id == 0) {
-		producer(&consumer_addr);
-		exit(0);
-	}
-
-	set_sig_handler(SIGURG);
-	signal_producer(pipefd[1]);
-
-	pfd = accept(lfd, (struct sockaddr *) &paddr, &len);
-	fcntl(pfd, F_SETOWN, getpid());
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 1:
-	 * veriyf that SIGURG is
-	 * delivered, 63 bytes are
-	 * read, oob is '@', and POLLPRI works.
-	 */
-	wait_for_data(pfd, POLLPRI);
-	read_oob(pfd, &oob);
-	len = read_data(pfd, buf, 1024);
-	if (!signal_recvd || len != 63 || oob != '@') {
-		fprintf(stderr, "Test 1 failed sigurg %d len %d %c\n",
-			 signal_recvd, len, oob);
-			die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 2:
-	 * Verify that the first OOB is over written by
-	 * the 2nd one and the first OOB is returned as
-	 * part of the read, and sigurg is received.
-	 */
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	len = 0;
-	while (len < 70)
-		len = recv(pfd, buf, 1024, MSG_PEEK);
-	len = read_data(pfd, buf, 1024);
-	read_oob(pfd, &oob);
-	if (!signal_recvd || len != 127 || oob != '#') {
-		fprintf(stderr, "Test 2 failed, sigurg %d len %d OOB %c\n",
-		signal_recvd, len, oob);
-		die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 3:
-	 * verify that 2nd oob over writes
-	 * the first one and read breaks at
-	 * oob boundary returning 127 bytes
-	 * and sigurg is received and atmark
-	 * is set.
-	 * oob is '%' and second read returns
-	 * 64 bytes.
-	 */
-	len = 0;
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	while (len < 150)
-		len = recv(pfd, buf, 1024, MSG_PEEK);
-	len = read_data(pfd, buf, 1024);
-	atmark = is_sioctatmark(pfd);
-	read_oob(pfd, &oob);
-
-	if (!signal_recvd || len != 127 || oob != '%' || atmark != 1) {
-		fprintf(stderr,
-			"Test 3 failed, sigurg %d len %d OOB %c atmark %d\n",
-			signal_recvd, len, oob, atmark);
-		die(1);
-	}
-
-	signal_recvd = 0;
-
-	len = read_data(pfd, buf, 1024);
-	if (len != 64) {
-		fprintf(stderr, "Test 3.1 failed, sigurg %d len %d OOB %c\n",
-			signal_recvd, len, oob);
-		die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 4:
-	 * verify that a single byte
-	 * oob message is delivered.
-	 * set non blocking mode and
-	 * check proper error is
-	 * returned and sigurg is
-	 * received and correct
-	 * oob is read.
-	 */
-
-	set_filemode(pfd, 0);
-
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	len = read_data(pfd, buf, 1024);
-	if ((len == -1) && (errno == 11))
-		len = 0;
-
-	read_oob(pfd, &oob);
-
-	if (!signal_recvd || len != 0 || oob != '@') {
-		fprintf(stderr, "Test 4 failed, sigurg %d len %d OOB %c\n",
-			 signal_recvd, len, oob);
-		die(1);
-	}
-
-	set_filemode(pfd, 1);
-
-	/* Inline Testing */
-
-	on = 1;
-	if (setsockopt(pfd, SOL_SOCKET, SO_OOBINLINE, &on, sizeof(on))) {
-		perror("SO_OOBINLINE");
-		die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 1 -- Inline:
-	 * Check that SIGURG is
-	 * delivered and 63 bytes are
-	 * read and oob is '@'
-	 */
-
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	len = read_data(pfd, buf, 1024);
-
-	if (!signal_recvd || len != 63) {
-		fprintf(stderr, "Test 1 Inline failed, sigurg %d len %d\n",
-			signal_recvd, len);
-		die(1);
-	}
-
-	len = read_data(pfd, buf, 1024);
-
-	if (len != 1) {
-		fprintf(stderr,
-			 "Test 1.1 Inline failed, sigurg %d len %d oob %c\n",
-			 signal_recvd, len, oob);
-		die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 2 -- Inline:
-	 * Verify that the first OOB is over written by
-	 * the 2nd one and read breaks correctly on
-	 * 2nd OOB boundary with the first OOB returned as
-	 * part of the read, and sigurg is delivered and
-	 * siocatmark returns true.
-	 * next read returns one byte, the oob byte
-	 * and siocatmark returns false.
-	 */
-	len = 0;
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	while (len < 70)
-		len = recv(pfd, buf, 1024, MSG_PEEK);
-	len = read_data(pfd, buf, 1024);
-	atmark = is_sioctatmark(pfd);
-	if (len != 127 || atmark != 1 || !signal_recvd) {
-		fprintf(stderr, "Test 2 Inline failed, len %d atmark %d\n",
-			 len, atmark);
-		die(1);
-	}
-
-	len = read_data(pfd, buf, 1024);
-	atmark = is_sioctatmark(pfd);
-	if (len != 1 || buf[0] != '#' || atmark == 1) {
-		fprintf(stderr, "Test 2.1 Inline failed, len %d data %c atmark %d\n",
-			len, buf[0], atmark);
-		die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 3 -- Inline:
-	 * verify that 2nd oob over writes
-	 * the first one and read breaks at
-	 * oob boundary returning 127 bytes
-	 * and sigurg is received and siocatmark
-	 * is true after the read.
-	 * subsequent read returns 65 bytes
-	 * because of oob which should be '%'.
-	 */
-	len = 0;
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	while (len < 126)
-		len = recv(pfd, buf, 1024, MSG_PEEK);
-	len = read_data(pfd, buf, 1024);
-	atmark = is_sioctatmark(pfd);
-	if (!signal_recvd || len != 127 || !atmark) {
-		fprintf(stderr,
-			 "Test 3 Inline failed, sigurg %d len %d data %c\n",
-			 signal_recvd, len, buf[0]);
-		die(1);
-	}
-
-	len = read_data(pfd, buf, 1024);
-	atmark = is_sioctatmark(pfd);
-	if (len != 65 || buf[0] != '%' || atmark != 0) {
-		fprintf(stderr,
-			 "Test 3.1 Inline failed, len %d oob %c atmark %d\n",
-			 len, buf[0], atmark);
-		die(1);
-	}
-
-	signal_recvd = 0;
-	signal_producer(pipefd[1]);
-
-	/* Test 4 -- Inline:
-	 * verify that a single
-	 * byte oob message is delivered
-	 * and read returns one byte, the oob
-	 * byte and sigurg is received
-	 */
-	wait_for_data(pfd, POLLIN | POLLPRI);
-	len = read_data(pfd, buf, 1024);
-	if (!signal_recvd || len != 1 || buf[0] != '@') {
-		fprintf(stderr,
-			"Test 4 Inline failed, signal %d len %d data %c\n",
-		signal_recvd, len, buf[0]);
-		die(1);
-	}
-	die(0);
-}