Commit 3f96a532 authored Sep 16, 2013 by Daniel Borkmann Committed by David S. Miller Sep 16, 2013

net: sctp: rfc4443: do not report ICMP redirects to user space



Adapt the same behaviour for SCTP as present in TCP for ICMP redirect
messages. For IPv6, RFC4443, section 2.4. says:

  ...
  (e) An ICMPv6 error message MUST NOT be originated as a result of
      receiving the following:
  ...
       (e.2) An ICMPv6 redirect message [IPv6-DISC].
  ...

Therefore, do not report an error to user space, just invoke dst's redirect
callback and leave, same for IPv4 as done in TCP as well. The implication
w/o having this patch could be that the reception of such packets would
generate a poll notification and in worst case it could even tear down the
whole connection. Therefore, stop updating sk_err on redirects.

Reported-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Suggested-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d82a7f54

net/sctp/input.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -634,8 +634,7 @@ void sctp_v4_err(struct sk_buff *skb, __u32 info)
		break;
		case ICMP_REDIRECT:
		sctp_icmp_redirect(sk, transport, skb);
		err = 0;
		break;
		/* Fall through to out_unlock. */
		default:
		goto out_unlock;
		}

net/sctp/ipv6.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -183,7 +183,7 @@ static void sctp_v6_err(struct sk_buff skb, struct inet6_skb_parm opt,
		break;
		case NDISC_REDIRECT:
		sctp_icmp_redirect(sk, transport, skb);
		break;
		goto out_unlock;
		default:
		break;
		}

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