Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:43510 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753027AbaCJTsj (ORCPT ); Mon, 10 Mar 2014 15:48:39 -0400 Date: Mon, 10 Mar 2014 15:48:33 -0400 From: "J. Bruce Fields" To: Jeff Layton Cc: linux-nfs@vger.kernel.org Subject: Re: [PATCH] svcrpc: explicitly reject compounds that are not padded out to 4-byte multiple Message-ID: <20140310194833.GG28006@fieldses.org> References: <1394465695-727-1-git-send-email-jlayton@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1394465695-727-1-git-send-email-jlayton@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Mar 10, 2014 at 11:34:55AM -0400, Jeff Layton wrote: > We have a WARN_ON in the nfsd4_decode_write() that tells us when the > client has sent a request that is not padded out properly according to > RFC4506. A WARN_ON really isn't appropriate in this case though since > this indicates a client bug, not a server one. > > Move this check out to the top-level compound decoder and have it just > explicitly return an error. Also add a dprintk() that shows the client > address and xid to help track down clients and frames that trigger it. OK, thanks.--b. > > Signed-off-by: Jeff Layton > --- > fs/nfsd/nfs4xdr.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c > index 63f2395c57ed..3a491dade169 100644 > --- a/fs/nfsd/nfs4xdr.c > +++ b/fs/nfsd/nfs4xdr.c > @@ -1222,7 +1222,6 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write) > } > write->wr_head.iov_base = p; > write->wr_head.iov_len = avail; > - WARN_ON(avail != (XDR_QUADLEN(avail) << 2)); > write->wr_pagelist = argp->pagelist; > > len = XDR_QUADLEN(write->wr_buflen) << 2; > @@ -3691,6 +3690,12 @@ int nfsd4_release_compoundargs(void *rq, __be32 *p, void *resp) > int > nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compoundargs *args) > { > + if (rqstp->rq_arg.head[0].iov_len % 4) { > + /* client is nuts */ > + dprintk("%s: compound not properly padded! (peeraddr=%pISc xid=0x%x)", > + __func__, svc_addr(rqstp), be32_to_cpu(rqstp->rq_xid)); > + return 0; > + } > args->p = p; > args->end = rqstp->rq_arg.head[0].iov_base + rqstp->rq_arg.head[0].iov_len; > args->pagelist = rqstp->rq_arg.pages; > -- > 1.8.5.3 >