ipv6: Inhibit IPv4-mapped src address on the wire.

Jonathan T. Leighton · davem330 · commit ec5e3b0a1d41 · 2017-02-14T12:13:51.000-05:00
This patch adds a check for the problematic case of an IPv4-mapped IPv6
source address and a destination address that is neither an IPv4-mapped
IPv6 address nor in6addr_any, and returns an appropriate error. The
check in done before returning from looking up the route.

Signed-off-by: Jonathan T. Leighton &lt;jtleight@udel.edu&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
@@ -1021,6 +1021,9 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
 		}
 	}
 #endif
+	if (ipv6_addr_v4mapped(&fl6->saddr) &&
+	    !(ipv6_addr_v4mapped(&fl6->daddr) || ipv6_addr_any(&fl6->daddr)))
+		return -EAFNOSUPPORT;
 
 	return 0;
 

Original file line number	Diff line number	Diff line change
`@@ -1021,6 +1021,9 @@ static int ip6_dst_lookup_tail(struct net net, const struct sock sk,`
`1021`	`1021`	`}`
`1022`	`1022`	`}`
`1023`	`1023`	`#endif`
	`1024`	`+ if (ipv6_addr_v4mapped(&fl6->saddr) &&`
	`1025`	`+ !(ipv6_addr_v4mapped(&fl6->daddr) \|\| ipv6_addr_any(&fl6->daddr)))`
	`1026`	`+ return -EAFNOSUPPORT;`
`1024`	`1027`
`1025`	`1028`	`return 0;`
`1026`	`1029`