ipv6: honor IPV6_PKTINFO with v4 mapped addresses on sendmsg
In case we decide in udp6_sendmsg to send the packet down the ipv4
udp_sendmsg path because the destination is either of family AF_INET or
the destination is an ipv4 mapped ipv6 address, we don't honor the
maybe specified ipv4 mapped ipv6 address in IPV6_PKTINFO.
We simply can check for this option in ip_cmsg_send because no calls to
ipv6 module functions are needed to do so.
Reported-by: Gert Doering <gert@space.net>
Cc: Tore Anderson <tore@fud.no>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 580dd96..0968b28 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -186,7 +186,8 @@
}
EXPORT_SYMBOL(ip_cmsg_recv);
-int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc)
+int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc,
+ bool allow_ipv6)
{
int err, val;
struct cmsghdr *cmsg;
@@ -194,6 +195,22 @@
for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
+#if defined(CONFIG_IPV6)
+ if (allow_ipv6 &&
+ cmsg->cmsg_level == SOL_IPV6 &&
+ cmsg->cmsg_type == IPV6_PKTINFO) {
+ struct in6_pktinfo *src_info;
+
+ if (cmsg->cmsg_len < CMSG_LEN(sizeof(*src_info)))
+ return -EINVAL;
+ src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
+ if (!ipv6_addr_v4mapped(&src_info->ipi6_addr))
+ return -EINVAL;
+ ipc->oif = src_info->ipi6_ifindex;
+ ipc->addr = src_info->ipi6_addr.s6_addr32[3];
+ continue;
+ }
+#endif
if (cmsg->cmsg_level != SOL_IP)
continue;
switch (cmsg->cmsg_type) {