Return-Path: Received: from fieldses.org ([173.255.197.46]:52398 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751923AbeEGQze (ORCPT ); Mon, 7 May 2018 12:55:34 -0400 Date: Mon, 7 May 2018 12:55:34 -0400 From: "J. Bruce Fields" To: Scott Mayhew Cc: jlayton@kernel.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH] nfsd: restrict rd_maxcount to svc_max_payload in nfsd_encode_readdir Message-ID: <20180507165534.GE4749@fieldses.org> References: <20180507130108.7136-1-smayhew@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180507130108.7136-1-smayhew@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Thanks, applying for 4.17 and stable.--b. On Mon, May 07, 2018 at 09:01:08AM -0400, Scott Mayhew wrote: > nfsd4_readdir_rsize restricts rd_maxcount to svc_max_payload when > estimating the size of the readdir reply, but nfsd_encode_readdir > restricts it to INT_MAX when encoding the reply. This can result in log > messages like "kernel: RPC request reserved 32896 but used 1049444". > > Restrict rd_dircount similarly (no reason it should be larger than > svc_max_payload). > > Signen-off-by: Scott Mayhew > --- > fs/nfsd/nfs4xdr.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c > index 1d048dd..cfe535c 100644 > --- a/fs/nfsd/nfs4xdr.c > +++ b/fs/nfsd/nfs4xdr.c > @@ -3651,7 +3651,8 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4 > nfserr = nfserr_resource; > goto err_no_verf; > } > - maxcount = min_t(u32, readdir->rd_maxcount, INT_MAX); > + maxcount = svc_max_payload(resp->rqstp); > + maxcount = min_t(u32, readdir->rd_maxcount, maxcount); > /* > * Note the rfc defines rd_maxcount as the size of the > * READDIR4resok structure, which includes the verifier above > @@ -3665,7 +3666,7 @@ nfsd4_encode_readdir(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4 > > /* RFC 3530 14.2.24 allows us to ignore dircount when it's 0: */ > if (!readdir->rd_dircount) > - readdir->rd_dircount = INT_MAX; > + readdir->rd_dircount = svc_max_payload(resp->rqstp); > > readdir->xdr = xdr; > readdir->rd_maxcount = maxcount; > -- > 2.9.5