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    Subject[011/205] tcp: tcp_synack_options() fix
    2.6.34-stable review patch.  If anyone has any objections, please let us know.

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


    From: Eric Dumazet <eric.dumazet@gmail.com>

    [ Upstream commit de213e5eedecdfb1b1eea7e6be28bc64cac5c078 ]

    Commit 33ad798c924b4a (tcp: options clean up) introduced a problem
    if MD5+SACK+timestamps were used in initial SYN message.

    Some stacks (old linux for example) try to negotiate MD5+SACK+TSTAMP
    sessions, but since 40 bytes of tcp options space are not enough to
    store all the bits needed, we chose to disable timestamps in this case.

    We send a SYN-ACK _without_ timestamp option, but socket has timestamps
    enabled and all further outgoing messages contain a TS block, all with
    the initial timestamp of the remote peer.

    Fix is to really disable timestamps option for the whole session.

    Reported-by: Bijay Singh <Bijay.Singh@guavus.com>
    Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    ---
    net/ipv4/tcp_output.c | 9 ++++-----
    1 file changed, 4 insertions(+), 5 deletions(-)

    --- a/net/ipv4/tcp_output.c
    +++ b/net/ipv4/tcp_output.c
    @@ -667,7 +667,6 @@ static unsigned tcp_synack_options(struc
    u8 cookie_plus = (xvp != NULL && !xvp->cookie_out_never) ?
    xvp->cookie_plus :
    0;
    - bool doing_ts = ireq->tstamp_ok;

    #ifdef CONFIG_TCP_MD5SIG
    *md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req);
    @@ -680,7 +679,7 @@ static unsigned tcp_synack_options(struc
    * rather than TS in order to fit in better with old,
    * buggy kernels, but that was deemed to be unnecessary.
    */
    - doing_ts &= !ireq->sack_ok;
    + ireq->tstamp_ok &= !ireq->sack_ok;
    }
    #else
    *md5 = NULL;
    @@ -695,7 +694,7 @@ static unsigned tcp_synack_options(struc
    opts->options |= OPTION_WSCALE;
    remaining -= TCPOLEN_WSCALE_ALIGNED;
    }
    - if (likely(doing_ts)) {
    + if (likely(ireq->tstamp_ok)) {
    opts->options |= OPTION_TS;
    opts->tsval = TCP_SKB_CB(skb)->when;
    opts->tsecr = req->ts_recent;
    @@ -703,7 +702,7 @@ static unsigned tcp_synack_options(struc
    }
    if (likely(ireq->sack_ok)) {
    opts->options |= OPTION_SACK_ADVERTISE;
    - if (unlikely(!doing_ts))
    + if (unlikely(!ireq->tstamp_ok))
    remaining -= TCPOLEN_SACKPERM_ALIGNED;
    }

    @@ -711,7 +710,7 @@ static unsigned tcp_synack_options(struc
    * If the <SYN> options fit, the same options should fit now!
    */
    if (*md5 == NULL &&
    - doing_ts &&
    + ireq->tstamp_ok &&
    cookie_plus > TCPOLEN_COOKIE_BASE) {
    int need = cookie_plus; /* has TCPOLEN_COOKIE_BASE */




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