Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751803AbdFAPrZ (ORCPT ); Thu, 1 Jun 2017 11:47:25 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33759 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752389AbdFAPpZ (ORCPT ); Thu, 1 Jun 2017 11:45:25 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Weston Andros Adamson" , "Anna Schumaker" , "J. Bruce Fields" Date: Thu, 01 Jun 2017 16:43:16 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 163/212] NFSv4: fix getacl ERANGE for some ACL buffer sizes In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1571 Lines: 48 3.16.44-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Weston Andros Adamson commit ed92d8c137b7794c2c2aa14479298b9885967607 upstream. We're not taking into account that the space needed for the (variable length) attr bitmap, with the result that we'd sometimes get a spurious ERANGE when the ACL data got close to the end of a page. Just add in an extra page to make sure. Signed-off-by: Weston Andros Adamson Signed-off-by: J. Bruce Fields Signed-off-by: Anna Schumaker Signed-off-by: Ben Hutchings --- fs/nfs/nfs4proc.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -4444,7 +4444,7 @@ out: */ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen) { - struct page *pages[NFS4ACL_MAXPAGES] = {NULL, }; + struct page *pages[NFS4ACL_MAXPAGES + 1] = {NULL, }; struct nfs_getaclargs args = { .fh = NFS_FH(inode), .acl_pages = pages, @@ -4458,13 +4458,9 @@ static ssize_t __nfs4_get_acl_uncached(s .rpc_argp = &args, .rpc_resp = &res, }; - unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE); + unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE) + 1; int ret = -ENOMEM, i; - /* As long as we're doing a round trip to the server anyway, - * let's be prepared for a page of acl data. */ - if (npages == 0) - npages = 1; if (npages > ARRAY_SIZE(pages)) return -ERANGE;