OpenAFS Master Repository branch, master, updated. BP-openafs-stable-1_8_x-476-g93aee3c

[Gerrit Code Review]

The following commit has been merged in the master branch:
commit ea276e83e37e5bd27285a3d639f2158639172786
Author: Andrew Deason <adeason@sinenomine.net>
Date:   Wed Aug 7 20:50:47 2019 -0500

    OPENAFS-SA-2019-001: Skip server OUT args on error
    
    Currently, part of our server-side RPC argument-handling code that's
    generated from rxgen looks like this (for example):
    
        z_result = SRXAFS_BulkStatus(z_call, &FidsArray, &StatArray, &CBArray, &Sync);
        z_xdrs->x_op = XDR_ENCODE;
        if ((!xdr_AFSBulkStats(z_xdrs, &StatArray))
             || (!xdr_AFSCBs(z_xdrs, &CBArray))
             || (!xdr_AFSVolSync(z_xdrs, &Sync)))
                z_result = RXGEN_SS_MARSHAL;
    fail:
        [...]
        return z_result;
    
    When the server routine for implementing the RPC results a non-zero
    value into z_result, the call will be aborted. However, before we
    abort the call, we still call the xdr_* routines with XDR_ENCODE for
    all of our output arguments. If the call has not already been aborted
    for other reasons, we'll serialize the output argument data into the
    Rx call. If we push more data than can fit in a single Rx packet for
    the call, then we'll also send that data to the client. Many server
    routines for implementing RPCs do not initialize the memory inside
    their output arguments during certain errors, and so the memory may be
    leaked to the peer.
    
    To avoid this, just jump to the 'fail' label when a nonzero 'z_result'
    is returned. This means we skip sending the output argument data to
    the peer, but we still free any argument data that needs freeing, and
    record the stats for the call (if needed). This makes the above
    example now look like this:
    
        z_result = SRXAFS_BulkStatus(z_call, &FidsArray, &StatArray, &CBArray, &Sync);
        if (z_result)
            goto fail;
        z_xdrs->x_op = XDR_ENCODE;
        if ((!xdr_AFSBulkStats(z_xdrs, &StatArray))
             || (!xdr_AFSCBs(z_xdrs, &CBArray))
             || (!xdr_AFSVolSync(z_xdrs, &Sync)))
                z_result = RXGEN_SS_MARSHAL;
    fail:
        [...]
        return z_result;
    
    Change-Id: I2bdea2e808bb215720492b0ba6ac1a88da61b954
    Reviewed-on: https://gerrit.openafs.org/13913
    Reviewed-by: Andrew Deason <adeason@sinenomine.net>
    Tested-by: BuildBot <buildbot@rampaginggeek.com>
    Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>

 src/rxgen/rpc_parse.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

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