• Chuck Lever's avatar
    svcauth_gss: Close connection when dropping an incoming message · 4d712ef1
    Chuck Lever authored
    S5.3.3.1 of RFC 2203 requires that an incoming GSS-wrapped message
    whose sequence number lies outside the current window is dropped.
    The rationale is:
    
      The reason for discarding requests silently is that the server
      is unable to determine if the duplicate or out of range request
      was due to a sequencing problem in the client, network, or the
      operating system, or due to some quirk in routing, or a replay
      attack by an intruder.  Discarding the request allows the client
      to recover after timing out, if indeed the duplication was
      unintentional or well intended.
    
    However, clients may rely on the server dropping the connection to
    indicate that a retransmit is needed. Without a connection reset, a
    client can wait forever without retransmitting, and the workload
    just stops dead. I've reproduced this behavior by running xfstests
    generic/323 on an NFSv4.0 mount with proto=rdma and sec=krb5i.
    
    To address this issue, have the server close the connection when it
    silently discards an incoming message due to a GSS sequence number
    problem.
    
    There are a few other places where the server will never reply.
    Change those spots in a similar fashion.
    Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
    Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
    4d712ef1
svc.c 33.9 KB