From: Ben Hutchings <ben.hutchings@codethink.co.uk>
To: Deepa Dinamani <deepa.kernel@gmail.com>,
viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org, arnd@arndb.de
Subject: Re: [Y2038] [PATCH 05/20] utimes: Clamp the timestamps before update
Date: Mon, 05 Aug 2019 14:30:43 +0100 [thread overview]
Message-ID: <12c095e595836a7ff7f2c7b2a32cb5544dd29b55.camel@codethink.co.uk> (raw)
In-Reply-To: <20190730014924.2193-6-deepa.kernel@gmail.com>
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 <deepa.kernel@gmail.com>
> ---
> 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
next prev parent reply other threads:[~2019-08-05 13:31 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 1:49 [PATCH 00/20] vfs: Add support for timestamp limits Deepa Dinamani
2019-07-30 1:49 ` [PATCH 01/20] vfs: Add file timestamp range support Deepa Dinamani
2019-07-30 1:49 ` [PATCH 02/20] vfs: Add timestamp_truncate() api Deepa Dinamani
2019-07-30 1:49 ` [PATCH 03/20] timestamp_truncate: Replace users of timespec64_trunc Deepa Dinamani
2019-07-30 8:27 ` OGAWA Hirofumi
2019-07-30 17:26 ` Deepa Dinamani
2019-07-30 22:28 ` Anton Altaparmakov
2019-07-31 0:08 ` Deepa Dinamani
2019-07-30 1:49 ` [PATCH 04/20] mount: Add mount warning for impending timestamp expiry Deepa Dinamani
2019-08-05 14:12 ` [Y2038] " Ben Hutchings
2019-08-05 14:40 ` Arnd Bergmann
2019-08-10 20:47 ` Deepa Dinamani
2019-08-05 14:14 ` Ben Hutchings
2019-08-10 20:44 ` Deepa Dinamani
2019-08-12 13:25 ` Ben Hutchings
2019-08-12 14:11 ` Arnd Bergmann
2019-08-12 16:09 ` Deepa Dinamani
2019-08-12 16:15 ` Deepa Dinamani
2019-08-12 17:43 ` Ben Hutchings
2019-07-30 1:49 ` [PATCH 05/20] utimes: Clamp the timestamps before update Deepa Dinamani
2019-07-31 15:14 ` Darrick J. Wong
2019-07-31 15:33 ` Deepa Dinamani
2019-08-05 13:30 ` Ben Hutchings [this message]
2019-08-10 20:36 ` [Y2038] " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 06/20] fs: Fill in max and min timestamps in superblock Deepa Dinamani
2019-07-31 15:28 ` Darrick J. Wong
2019-07-30 1:49 ` [PATCH 07/20] 9p: Fill min and max timestamps in sb Deepa Dinamani
2019-07-30 1:49 ` [PATCH 08/20] adfs: Fill in max and min " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 09/20] ext4: Initialize timestamps limits Deepa Dinamani
2019-07-31 15:26 ` Darrick J. Wong
2019-08-01 19:18 ` Deepa Dinamani
2019-08-01 22:43 ` Theodore Y. Ts'o
2019-08-02 10:39 ` Arnd Bergmann
2019-08-02 15:43 ` Theodore Y. Ts'o
2019-08-02 19:00 ` Arnd Bergmann
2019-08-02 21:39 ` Theodore Y. Ts'o
2019-08-03 9:30 ` Arnd Bergmann
2019-08-03 16:02 ` Theodore Y. Ts'o
2019-08-03 20:24 ` Arnd Bergmann
2019-08-07 18:04 ` Andreas Dilger
2019-08-08 18:27 ` Deepa Dinamani
2019-07-30 1:49 ` [PATCH 10/20] fs: nfs: Initialize filesystem timestamp ranges Deepa Dinamani
2019-07-30 1:49 ` [PATCH 11/20] fs: cifs: " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 12/20] fs: fat: " Deepa Dinamani
2019-07-30 9:31 ` OGAWA Hirofumi
2019-07-30 17:39 ` Deepa Dinamani
2019-07-31 0:48 ` OGAWA Hirofumi
2019-07-30 1:49 ` [PATCH 13/20] fs: affs: " Deepa Dinamani
2019-08-01 11:28 ` David Sterba
2019-07-30 1:49 ` [PATCH 14/20] fs: sysv: " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 15/20] fs: ceph: " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 16/20] fs: orangefs: " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 17/20] fs: hpfs: " Deepa Dinamani
2019-07-30 1:49 ` [PATCH 18/20] fs: omfs: " Deepa Dinamani
2019-07-30 14:25 ` Bob Copeland
2019-07-30 1:49 ` [PATCH 19/20] pstore: fs superblock limits Deepa Dinamani
2019-07-30 4:31 ` Kees Cook
2019-07-30 7:36 ` Arnd Bergmann
2019-08-02 2:26 ` Deepa Dinamani
2019-08-02 7:15 ` Arnd Bergmann
2019-08-18 14:00 ` Deepa Dinamani
2019-07-30 1:49 ` [PATCH 20/20] isofs: Initialize filesystem timestamp ranges Deepa Dinamani
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