[PATCH net 1/2] ioam6: drop the packet if no outer source address is available

[Justin Iurman <justin.iurman@gmail.com>]

When no tunnel source is configured, ioam6_do_encap() ignores the
return value of ipv6_dev_get_saddr(). On failure, the outer header
keeps the source address copied from the inner header, so the packet
is sent with an address that may not belong to this node.

Drop the packet instead.

Fixes: 8cb3bf8bff3c ("ipv6: ioam: Add support for the ip6ip6 encapsulation")
Signed-off-by: Justin Iurman <justin.iurman@gmail.com>
---
 net/ipv6/ioam6_iptunnel.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c
index cfb2c41634a0..4990ae1ee78c 100644
--- a/net/ipv6/ioam6_iptunnel.c
+++ b/net/ipv6/ioam6_iptunnel.c
@@ -324,11 +324,14 @@ static int ioam6_do_encap(struct net *net, struct sk_buff *skb,
 	hdr->payload_len = cpu_to_be16(skb->len - sizeof(*hdr));
 	hdr->daddr = *tundst;
 
-	if (has_tunsrc)
+	if (has_tunsrc) {
 		memcpy(&hdr->saddr, tunsrc, sizeof(*tunsrc));
-	else
-		ipv6_dev_get_saddr(net, dst_dev(dst), &hdr->daddr,
-				   IPV6_PREFER_SRC_PUBLIC, &hdr->saddr);
+	} else {
+		err = ipv6_dev_get_saddr(net, dst_dev(dst), &hdr->daddr,
+					 IPV6_PREFER_SRC_PUBLIC, &hdr->saddr);
+		if (unlikely(err))
+			return err;
+	}
 
 	skb_postpush_rcsum(skb, hdr, len);
 
-- 
2.34.1