lkml.org 
[lkml]   [2011]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[34-longterm 138/209] tcp: Increase TCP_MAXSEG socket option minimum.
    Date
    From: David S. Miller <davem@davemloft.net>

    =====================================================================
    | This is a commit scheduled for the next v2.6.34 longterm release. |
    | If you see a problem with using this for longterm, please comment.|
    =====================================================================

    commit 7a1abd08d52fdeddb3e9a5a33f2f15cc6a5674d2 upstream

    As noted by Steve Chen, since commit
    f5fff5dc8a7a3f395b0525c02ba92c95d42b7390 ("tcp: advertise MSS
    requested by user") we can end up with a situation where
    tcp_select_initial_window() does a divide by a zero (or
    even negative) mss value.

    The problem is that sometimes we effectively subtract
    TCPOLEN_TSTAMP_ALIGNED and/or TCPOLEN_MD5SIG_ALIGNED from the mss.

    Fix this by increasing the minimum from 8 to 64.

    Reported-by: Steve Chen <schen@mvista.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
    ---
    net/ipv4/tcp.c | 2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)

    diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
    index 68cd299..5ad716b 100644
    --- a/net/ipv4/tcp.c
    +++ b/net/ipv4/tcp.c
    @@ -2234,7 +2234,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
    /* Values greater than interface MTU won't take effect. However
    * at the point when this call is done we typically don't yet
    * know which interface is going to be used */
    - if (val < 8 || val > MAX_TCP_WINDOW) {
    + if (val < 64 || val > MAX_TCP_WINDOW) {
    err = -EINVAL;
    break;
    }
    --
    1.7.4.4


    \
     
     \ /
      Last update: 2011-04-14 20:21    [W:0.027 / U:0.552 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site