net: diag: support v4mapped sockets in inet_diag_find_one_icsk()

BugLink: https://bugs.launchpad.net/bugs/1826212

[ Upstream commit 7c130672 ]

Lorenzo reported that we could not properly find v4mapped sockets
in inet_diag_find_one_icsk(). This patch fixes the issue.
Reported-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

net/ipv4/inet_diag.c

@@ -366,13 +366,20 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo *hashinfo,
 				 req->id.idiag_dport, req->id.idiag_src[0],
 				 req->id.idiag_sport, req->id.idiag_if);
 #if IS_ENABLED(CONFIG_IPV6)
-	else if (req->sdiag_family == AF_INET6)
-		sk = inet6_lookup(net, hashinfo,
-				  (struct in6_addr *)req->id.idiag_dst,
-				  req->id.idiag_dport,
-				  (struct in6_addr *)req->id.idiag_src,
-				  req->id.idiag_sport,
-				  req->id.idiag_if);
+	else if (req->sdiag_family == AF_INET6) {
+		if (ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_dst) &&
+		    ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_src))
+			sk = inet_lookup(net, hashinfo, req->id.idiag_dst[3],
+					 req->id.idiag_dport, req->id.idiag_src[3],
+					 req->id.idiag_sport, req->id.idiag_if);
+		else
+			sk = inet6_lookup(net, hashinfo,
+					  (struct in6_addr *)req->id.idiag_dst,
+					  req->id.idiag_dport,
+					  (struct in6_addr *)req->id.idiag_src,
+					  req->id.idiag_sport,
+					  req->id.idiag_if);
+	}
 #endif
 	else
 		goto out_nosk;