Merge branch 'tcp-bind-fixes'

Kuniyuki Iwashima says:

====================
tcp: Fix bind() regression for v4-mapped-v6 address

Since bhash2 was introduced, bind() is broken in two cases related
to v4-mapped-v6 address.

This series fixes the regression and adds test to cover the cases.

Changes:
  v2:
    * Added patch 1 to factorise duplicated comparison (Eric Dumazet)

  v1: https://lore.kernel.org/netdev/20230911165106.39384-1-kuniyu@amazon.com/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 82 insertions, 27 deletions

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index fe274c122a56..c6932d1a3fa8 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -784,6 +784,11 @@ static inline bool ipv6_addr_v4mapped(const struct in6_addr *a)
 					cpu_to_be32(0x0000ffff))) == 0UL;
 }
 
+static inline bool ipv6_addr_v4mapped_any(const struct in6_addr *a)
+{
+	return ipv6_addr_v4mapped(a) && ipv4_is_zeronet(a->s6_addr32[3]);
+}
+
 static inline bool ipv6_addr_v4mapped_loopback(const struct in6_addr *a)
 {
 	return ipv6_addr_v4mapped(a) && ipv4_is_loopback(a->s6_addr32[3]);
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 7876b7d703cb..c32f5e28758b 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -815,41 +815,45 @@ static bool inet_bind2_bucket_match(const struct inet_bind2_bucket *tb,
 				    const struct net *net, unsigned short port,
 				    int l3mdev, const struct sock *sk)
 {
+	if (!net_eq(ib2_net(tb), net) || tb->port != port ||
+	    tb->l3mdev != l3mdev)
+		return false;
+
 #if IS_ENABLED(CONFIG_IPV6)
-	if (sk->sk_family != tb->family)
+	if (sk->sk_family != tb->family) {
+		if (sk->sk_family == AF_INET)
+			return ipv6_addr_v4mapped(&tb->v6_rcv_saddr) &&
+				tb->v6_rcv_saddr.s6_addr32[3] == sk->sk_rcv_saddr;
+
 		return false;
+	}
 
 	if (sk->sk_family == AF_INET6)
-		return net_eq(ib2_net(tb), net) && tb->port == port &&
-			tb->l3mdev == l3mdev &&
-			ipv6_addr_equal(&tb->v6_rcv_saddr, &sk->sk_v6_rcv_saddr);
-	else
+		return ipv6_addr_equal(&tb->v6_rcv_saddr, &sk->sk_v6_rcv_saddr);
 #endif
-		return net_eq(ib2_net(tb), net) && tb->port == port &&
-			tb->l3mdev == l3mdev && tb->rcv_saddr == sk->sk_rcv_saddr;
+	return tb->rcv_saddr == sk->sk_rcv_saddr;
 }
 
 bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb, const struct net *net,
 				      unsigned short port, int l3mdev, const struct sock *sk)
 {
+	if (!net_eq(ib2_net(tb), net) || tb->port != port ||
+	    tb->l3mdev != l3mdev)
+		return false;
+
 #if IS_ENABLED(CONFIG_IPV6)
 	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_any(&tb->v6_rcv_saddr);
+			return ipv6_addr_any(&tb->v6_rcv_saddr) ||
+				ipv6_addr_v4mapped_any(&tb->v6_rcv_saddr);
 
 		return false;
 	}
 
 	if (sk->sk_family == AF_INET6)
-		return net_eq(ib2_net(tb), net) && tb->port == port &&
-			tb->l3mdev == l3mdev &&
-			ipv6_addr_any(&tb->v6_rcv_saddr);
-	else
+		return ipv6_addr_any(&tb->v6_rcv_saddr);
 #endif
-		return net_eq(ib2_net(tb), net) && tb->port == port &&
-			tb->l3mdev == l3mdev && tb->rcv_saddr == 0;
+	return tb->rcv_saddr == 0;
 }
 
 /* The socket's bhash2 hashbucket spinlock must be held when this is called */
diff --git a/tools/testing/selftests/net/bind_wildcard.c b/tools/testing/selftests/net/bind_wildcard.c
index 58edfc15d28b..a2662348cdb1 100644
--- a/tools/testing/selftests/net/bind_wildcard.c
+++ b/tools/testing/selftests/net/bind_wildcard.c
@@ -6,41 +6,91 @@
 
 #include "../kselftest_harness.h"
 
+struct in6_addr in6addr_v4mapped_any = {
+	.s6_addr = {
+		0, 0, 0, 0,
+		0, 0, 0, 0,
+		0, 0, 255, 255,
+		0, 0, 0, 0
+	}
+};
+
+struct in6_addr in6addr_v4mapped_loopback = {
+	.s6_addr = {
+		0, 0, 0, 0,
+		0, 0, 0, 0,
+		0, 0, 255, 255,
+		127, 0, 0, 1
+	}
+};
+
 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;
+	int expected_errno;
 };
 
 FIXTURE_VARIANT_ADD(bind_wildcard, v4_any_v6_any)
 {
 	.addr4_const = INADDR_ANY,
 	.addr6_const = &in6addr_any,
+	.expected_errno = EADDRINUSE,
 };
 
 FIXTURE_VARIANT_ADD(bind_wildcard, v4_any_v6_local)
 {
 	.addr4_const = INADDR_ANY,
 	.addr6_const = &in6addr_loopback,
+	.expected_errno = 0,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_any_v6_v4mapped_any)
+{
+	.addr4_const = INADDR_ANY,
+	.addr6_const = &in6addr_v4mapped_any,
+	.expected_errno = EADDRINUSE,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_any_v6_v4mapped_local)
+{
+	.addr4_const = INADDR_ANY,
+	.addr6_const = &in6addr_v4mapped_loopback,
+	.expected_errno = EADDRINUSE,
 };
 
 FIXTURE_VARIANT_ADD(bind_wildcard, v4_local_v6_any)
 {
 	.addr4_const = INADDR_LOOPBACK,
 	.addr6_const = &in6addr_any,
+	.expected_errno = EADDRINUSE,
 };
 
 FIXTURE_VARIANT_ADD(bind_wildcard, v4_local_v6_local)
 {
 	.addr4_const = INADDR_LOOPBACK,
 	.addr6_const = &in6addr_loopback,
+	.expected_errno = 0,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_local_v6_v4mapped_any)
+{
+	.addr4_const = INADDR_LOOPBACK,
+	.addr6_const = &in6addr_v4mapped_any,
+	.expected_errno = EADDRINUSE,
+};
+
+FIXTURE_VARIANT_ADD(bind_wildcard, v4_local_v6_v4mapped_local)
+{
+	.addr4_const = INADDR_LOOPBACK,
+	.addr6_const = &in6addr_v4mapped_loopback,
+	.expected_errno = EADDRINUSE,
 };
 
 FIXTURE_SETUP(bind_wildcard)
@@ -52,11 +102,6 @@ FIXTURE_SETUP(bind_wildcard)
 	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)
@@ -65,6 +110,7 @@ FIXTURE_TEARDOWN(bind_wildcard)
 
 void bind_sockets(struct __test_metadata *_metadata,
 		  FIXTURE_DATA(bind_wildcard) *self,
+		  int expected_errno,
 		  struct sockaddr *addr1, socklen_t addrlen1,
 		  struct sockaddr *addr2, socklen_t addrlen2)
 {
@@ -86,9 +132,9 @@ void bind_sockets(struct __test_metadata *_metadata,
 	ASSERT_GT(fd[1], 0);
 
 	ret = bind(fd[1], addr2, addrlen2);
-	if (self->expected_errno) {
+	if (expected_errno) {
 		ASSERT_EQ(ret, -1);
-		ASSERT_EQ(errno, self->expected_errno);
+		ASSERT_EQ(errno, expected_errno);
 	} else {
 		ASSERT_EQ(ret, 0);
 	}
@@ -99,14 +145,14 @@ void bind_sockets(struct __test_metadata *_metadata,
 
 TEST_F(bind_wildcard, v4_v6)
 {
-	bind_sockets(_metadata, self,
-		     (struct sockaddr *)&self->addr4, sizeof(self->addr6),
+	bind_sockets(_metadata, self, variant->expected_errno,
+		     (struct sockaddr *)&self->addr4, sizeof(self->addr4),
 		     (struct sockaddr *)&self->addr6, sizeof(self->addr6));
 }
 
 TEST_F(bind_wildcard, v6_v4)
 {
-	bind_sockets(_metadata, self,
+	bind_sockets(_metadata, self, variant->expected_errno,
 		     (struct sockaddr *)&self->addr6, sizeof(self->addr6),
 		     (struct sockaddr *)&self->addr4, sizeof(self->addr4));
 }