lkml.org 
[lkml]   [2019]   [Feb]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Date
    Subject[PATCH 3.16 142/305] sunrpc: correct the computation for page_ptr when truncating
    3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

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

    From: Frank Sorenson <sorenson@redhat.com>

    commit 5d7a5bcb67c70cbc904057ef52d3fcfeb24420bb upstream.

    When truncating the encode buffer, the page_ptr is getting
    advanced, causing the next page to be skipped while encoding.
    The page is still included in the response, so the response
    contains a page of bogus data.

    We need to adjust the page_ptr backwards to ensure we encode
    the next page into the correct place.

    We saw this triggered when concurrent directory modifications caused
    nfsd4_encode_direct_fattr() to return nfserr_noent, and the resulting
    call to xdr_truncate_encode() corrupted the READDIR reply.

    Signed-off-by: Frank Sorenson <sorenson@redhat.com>
    Signed-off-by: J. Bruce Fields <bfields@redhat.com>
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    net/sunrpc/xdr.c | 5 ++---
    1 file changed, 2 insertions(+), 3 deletions(-)

    --- a/net/sunrpc/xdr.c
    +++ b/net/sunrpc/xdr.c
    @@ -637,11 +637,10 @@ void xdr_truncate_encode(struct xdr_stre
    /* xdr->iov should already be NULL */
    return;
    }
    - if (fraglen) {
    + if (fraglen)
    xdr->end = head->iov_base + head->iov_len;
    - xdr->page_ptr--;
    - }
    /* (otherwise assume xdr->end is already set) */
    + xdr->page_ptr--;
    head->iov_len = len;
    buf->len = len;
    xdr->p = head->iov_base + head->iov_len;
    \
     
     \ /
      Last update: 2019-02-03 15:00    [W:2.726 / U:0.148 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site