From: Trond Myklebust trond.myklebust@hammerspace.com
commit f2e717d655040d632c9015f19aa4275f8b16e7f2 upstream.
RFC3530 notes that the 'dircount' field may be zero, in which case the recommendation is to ignore it, and only enforce the 'maxcount' field. In RFC5661, this recommendation to ignore a zero valued field becomes a requirement.
Fixes: aee377644146 ("nfsd4: fix rd_dircount enforcement") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/nfs4xdr.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-)
--- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3131,15 +3131,18 @@ nfsd4_encode_dirent(void *ccdv, const ch goto fail; cd->rd_maxcount -= entry_bytes; /* - * RFC 3530 14.2.24 describes rd_dircount as only a "hint", so - * let's always let through the first entry, at least: + * RFC 3530 14.2.24 describes rd_dircount as only a "hint", and + * notes that it could be zero. If it is zero, then the server + * should enforce only the rd_maxcount value. */ - if (!cd->rd_dircount) - goto fail; - name_and_cookie = 4 + 4 * XDR_QUADLEN(namlen) + 8; - if (name_and_cookie > cd->rd_dircount && cd->cookie_offset) - goto fail; - cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie); + if (cd->rd_dircount) { + name_and_cookie = 4 + 4 * XDR_QUADLEN(namlen) + 8; + if (name_and_cookie > cd->rd_dircount && cd->cookie_offset) + goto fail; + cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie); + if (!cd->rd_dircount) + cd->rd_maxcount = 0; + }
cd->cookie_offset = cookie_offset; skip_entry: