lkml.org 
[lkml]   [2014]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.10 05/18] netfilter: ipv4: defrag: set local_df flag on defragmented skb
    Date
    3.10-stable review patch.  If anyone has any objections, please let me know.

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

    From: Florian Westphal <fw@strlen.de>

    commit 895162b1101b3ea5db08ca6822ae9672717efec0 upstream.

    else we may fail to forward skb even if original fragments do fit
    outgoing link mtu:

    1. remote sends 2k packets in two 1000 byte frags, DF set
    2. we want to forward but only see '2k > mtu and DF set'
    3. we then send icmp error saying that outgoing link is 1500

    But original sender never sent a packet that would not fit
    the outgoing link.

    Setting local_df makes outgoing path test size vs.
    IPCB(skb)->frag_max_size, so we will still send the correct
    error in case the largest original size did not fit
    outgoing link mtu.

    Reported-by: Maxime Bizon <mbizon@freebox.fr>
    Suggested-by: Maxime Bizon <mbizon@freebox.fr>
    Fixes: 5f2d04f1f9 (ipv4: fix path MTU discovery with connection tracking)
    Signed-off-by: Florian Westphal <fw@strlen.de>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
    Cc: Jiri Slaby <jslaby@suse.cz>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    net/ipv4/netfilter/nf_defrag_ipv4.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    --- a/net/ipv4/netfilter/nf_defrag_ipv4.c
    +++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
    @@ -22,7 +22,6 @@
    #endif
    #include <net/netfilter/nf_conntrack_zones.h>

    -/* Returns new sk_buff, or NULL */
    static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
    {
    int err;
    @@ -33,8 +32,10 @@ static int nf_ct_ipv4_gather_frags(struc
    err = ip_defrag(skb, user);
    local_bh_enable();

    - if (!err)
    + if (!err) {
    ip_send_check(ip_hdr(skb));
    + skb->local_df = 1;
    + }

    return err;
    }



    \
     
     \ /
      Last update: 2014-06-13 02:01    [W:4.223 / U:1.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site