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    Subject[PATCH 3.8 44/81] net: sctp: rfc4443: do not report ICMP redirects to user space
    Date
    3.8.13.12 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Daniel Borkmann <dborkman@redhat.com>

    [ Upstream commit 3f96a532113131d5a65ac9e00fc83cfa31b0295f ]

    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>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    net/sctp/input.c | 3 +--
    net/sctp/ipv6.c | 2 +-
    2 files changed, 2 insertions(+), 3 deletions(-)

    diff --git a/net/sctp/input.c b/net/sctp/input.c
    index 8bd3c27..08708c6 100644
    --- a/net/sctp/input.c
    +++ b/net/sctp/input.c
    @@ -649,8 +649,7 @@ 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;
    }
    diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
    index d70cabb..422d8bd 100644
    --- a/net/sctp/ipv6.c
    +++ b/net/sctp/ipv6.c
    @@ -189,7 +189,7 @@ SCTP_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;
    }
    --
    1.8.1.2


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