Merge branch 'tcp-fix-bind-regression-for-dual-stack-wildcard-address'

Kuniyuki Iwashima says:

====================
tcp: Fix bind() regression for dual-stack wildcard address.

The first patch fixes the regression reported in [0], and the second
patch adds a test for similar cases to catch future regression.

[0]: https://lore.kernel.org/netdev/e21bf153-80b0-9ec0-15ba-e04a4ad42c34@redhat.com/
====================

Link: https://lore.kernel.org/r/20230312031904.4674-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 123 insertions, 1 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index e41fdc38ce19..6edae3886885 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -828,8 +828,14 @@ bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb, const
 #if IS_ENABLED(CONFIG_IPV6)
 	struct in6_addr addr_any = {};
 
-	if (sk->sk_family != tb->family)
+	if (sk->sk_family != tb->family) {
+		if (sk->sk_family == AF_INET)
+			return net_eq(ib2_net(tb), net) && tb->port == port &&
+				tb->l3mdev == l3mdev &&
+				ipv6_addr_equal(&tb->v6_rcv_saddr, &addr_any);
+
 		return false;
+	}
 
 	if (sk->sk_family == AF_INET6)
 		return net_eq(ib2_net(tb), net) && tb->port == port &&
diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
index a6911cae368c..80f06aa62034 100644
--- a/tools/testing/selftests/net/.gitignore
+++ b/tools/testing/selftests/net/.gitignore
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 bind_bhash
 bind_timewait
+bind_wildcard
 csum
 cmsg_sender
 diag_uid
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 6cd8993454d7..80fbfe0330f6 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -80,6 +80,7 @@ TEST_GEN_FILES += sctp_hello
 TEST_GEN_FILES += csum
 TEST_GEN_FILES += nat6to4.o
 TEST_GEN_FILES += ip_local_port_range
+TEST_GEN_FILES += bind_wildcard
 
 TEST_FILES := settings
 
diff --git a/tools/testing/selftests/net/bind_wildcard.c b/tools/testing/selftests/net/bind_wildcard.c
new file mode 100644
index 000000000000..58edfc15d28b
--- /dev/null
+++ b/tools/testing/selftests/net/bind_wildcard.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright Amazon.com Inc. or its affiliates. */
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include "../kselftest_harness.h"
+
+FIXTURE(bind_wildcard)
+{
+	struct sockaddr_in addr4;
+	struct sockaddr_in6 addr6;
+	int expected_errno;
+};
+
+FIXTURE_VARIANT(bind_wildcard)
+{
+	const __u32 addr4_const;
+	const struct in6_addr *addr6_const;
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_any_v6_any)
+{
+	.addr4_const = INADDR_ANY,
+	.addr6_const = &in6addr_any,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_any_v6_local)
+{
+	.addr4_const = INADDR_ANY,
+	.addr6_const = &in6addr_loopback,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_local_v6_any)
+{
+	.addr4_const = INADDR_LOOPBACK,
+	.addr6_const = &in6addr_any,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_local_v6_local)
+{
+	.addr4_const = INADDR_LOOPBACK,
+	.addr6_const = &in6addr_loopback,
+};
+
+FIXTURE_SETUP(bind_wildcard)
+{
+	self->addr4.sin_family = AF_INET;
+	self->addr4.sin_port = htons(0);
+	self->addr4.sin_addr.s_addr = htonl(variant->addr4_const);
+
+	self->addr6.sin6_family = AF_INET6;
+	self->addr6.sin6_port = htons(0);
+	self->addr6.sin6_addr = *variant->addr6_const;
+
+	if (variant->addr6_const == &in6addr_any)
+		self->expected_errno = EADDRINUSE;
+	else
+		self->expected_errno = 0;
+}
+
+FIXTURE_TEARDOWN(bind_wildcard)
+{
+}
+
+void bind_sockets(struct __test_metadata *_metadata,
+		  FIXTURE_DATA(bind_wildcard) *self,
+		  struct sockaddr *addr1, socklen_t addrlen1,
+		  struct sockaddr *addr2, socklen_t addrlen2)
+{
+	int fd[2];
+	int ret;
+
+	fd[0] = socket(addr1->sa_family, SOCK_STREAM, 0);
+	ASSERT_GT(fd[0], 0);
+
+	ret = bind(fd[0], addr1, addrlen1);
+	ASSERT_EQ(ret, 0);
+
+	ret = getsockname(fd[0], addr1, &addrlen1);
+	ASSERT_EQ(ret, 0);
+
+	((struct sockaddr_in *)addr2)->sin_port = ((struct sockaddr_in *)addr1)->sin_port;
+
+	fd[1] = socket(addr2->sa_family, SOCK_STREAM, 0);
+	ASSERT_GT(fd[1], 0);
+
+	ret = bind(fd[1], addr2, addrlen2);
+	if (self->expected_errno) {
+		ASSERT_EQ(ret, -1);
+		ASSERT_EQ(errno, self->expected_errno);
+	} else {
+		ASSERT_EQ(ret, 0);
+	}
+
+	close(fd[1]);
+	close(fd[0]);
+}
+
+TEST_F(bind_wildcard, v4_v6)
+{
+	bind_sockets(_metadata, self,
+		     (struct sockaddr *)&self->addr4, sizeof(self->addr6),
+		     (struct sockaddr *)&self->addr6, sizeof(self->addr6));
+}
+
+TEST_F(bind_wildcard, v6_v4)
+{
+	bind_sockets(_metadata, self,
+		     (struct sockaddr *)&self->addr6, sizeof(self->addr6),
+		     (struct sockaddr *)&self->addr4, sizeof(self->addr4));
+}
+
+TEST_HARNESS_MAIN