From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73E21C0650F for ; Mon, 5 Aug 2019 13:30:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 534072087B for ; Mon, 5 Aug 2019 13:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730228AbfHENav (ORCPT ); Mon, 5 Aug 2019 09:30:51 -0400 Received: from imap1.codethink.co.uk ([176.9.8.82]:58279 "EHLO imap1.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729291AbfHENar (ORCPT ); Mon, 5 Aug 2019 09:30:47 -0400 Received: from [167.98.27.226] (helo=xylophone) by imap1.codethink.co.uk with esmtpsa (Exim 4.84_2 #1 (Debian)) id 1hud4W-0004bY-Ou; Mon, 05 Aug 2019 14:30:44 +0100 Message-ID: <12c095e595836a7ff7f2c7b2a32cb5544dd29b55.camel@codethink.co.uk> Subject: Re: [Y2038] [PATCH 05/20] utimes: Clamp the timestamps before update From: Ben Hutchings To: Deepa Dinamani , viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org, arnd@arndb.de Date: Mon, 05 Aug 2019 14:30:43 +0100 In-Reply-To: <20190730014924.2193-6-deepa.kernel@gmail.com> References: <20190730014924.2193-1-deepa.kernel@gmail.com> <20190730014924.2193-6-deepa.kernel@gmail.com> Organization: Codethink Ltd. Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5-1.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-07-29 at 18:49 -0700, Deepa Dinamani wrote: > POSIX is ambiguous on the behavior of timestamps for > futimens, utimensat and utimes. Whether to return an > error or silently clamp a timestamp beyond the range > supported by the underlying filesystems is not clear. > > POSIX.1 section for futimens, utimensat and utimes says: > (http://pubs.opengroup.org/onlinepubs/9699919799/functions/futimens.html) > > The file's relevant timestamp shall be set to the greatest > value supported by the file system that is not greater > than the specified time. > > If the tv_nsec field of a timespec structure has the special > value UTIME_NOW, the file's relevant timestamp shall be set > to the greatest value supported by the file system that is > not greater than the current time. > > [EINVAL] > A new file timestamp would be a value whose tv_sec > component is not a value supported by the file system. > > The patch chooses to clamp the timestamps according to the > filesystem timestamp ranges and does not return an error. > This is in line with the behavior of utime syscall also > since the POSIX page(http://pubs.opengroup.org/onlinepubs/009695399/functions/utime.html) > for utime does not mention returning an error or clamping like above. > > Same for utimes http://pubs.opengroup.org/onlinepubs/009695399/functions/utimes.html > > Signed-off-by: Deepa Dinamani > --- > fs/utimes.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/fs/utimes.c b/fs/utimes.c > index 350c9c16ace1..4c1a2ce90bbc 100644 > --- a/fs/utimes.c > +++ b/fs/utimes.c > @@ -21,6 +21,7 @@ static int utimes_common(const struct path *path, struct timespec64 *times) > int error; > struct iattr newattrs; > struct inode *inode = path->dentry->d_inode; > + struct super_block *sb = inode->i_sb; > struct inode *delegated_inode = NULL; > > error = mnt_want_write(path->mnt); > @@ -36,16 +37,24 @@ static int utimes_common(const struct path *path, struct timespec64 *times) > if (times[0].tv_nsec == UTIME_OMIT) > newattrs.ia_valid &= ~ATTR_ATIME; > else if (times[0].tv_nsec != UTIME_NOW) { > - newattrs.ia_atime.tv_sec = times[0].tv_sec; > - newattrs.ia_atime.tv_nsec = times[0].tv_nsec; > + newattrs.ia_atime.tv_sec = > + clamp(times[0].tv_sec, sb->s_time_min, sb->s_time_max); > + if (times[0].tv_sec == sb->s_time_max || times[0].tv_sec == sb->s_time_min) This is testing the un-clamped value. > + newattrs.ia_atime.tv_nsec = 0; > + else > + newattrs.ia_atime.tv_nsec = times[0].tv_nsec; > newattrs.ia_valid |= ATTR_ATIME_SET; > } > > if (times[1].tv_nsec == UTIME_OMIT) > newattrs.ia_valid &= ~ATTR_MTIME; > else if (times[1].tv_nsec != UTIME_NOW) { > - newattrs.ia_mtime.tv_sec = times[1].tv_sec; > - newattrs.ia_mtime.tv_nsec = times[1].tv_nsec; > + newattrs.ia_mtime.tv_sec = > + clamp(times[1].tv_sec, sb->s_time_min, sb->s_time_max); > + if (times[1].tv_sec >= sb->s_time_max || times[1].tv_sec == sb->s_time_min) Similarly here, for the minimum. I suggest testing for clamping like this: if (newattrs.ia_atime.tv_sec != times[0].tv_sec) ... if (newattrs.ia_mtime.tv_sec != times[1].tv_sec) ... Ben. > + newattrs.ia_mtime.tv_nsec = 0; > + else > + newattrs.ia_mtime.tv_nsec = times[1].tv_nsec; > newattrs.ia_valid |= ATTR_MTIME_SET; > } > /* -- Ben Hutchings, Software Developer Codethink Ltd https://www.codethink.co.uk/ Dale House, 35 Dale Street Manchester, M1 2HF, United Kingdom