From: Jan Kara <jack@suse.cz>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: matthew.garrett@nebula.com, yuchao0@huawei.com, tytso@mit.edu,
ard.biesheuvel@linaro.org, josef@toxicpanda.com, clm@fb.com,
adilger.kernel@dilger.ca, viro@zeniv.linux.org.uk, jack@suse.com,
dsterba@suse.com, jaegeuk@kernel.org, jk@ozlabs.org,
reiserfs-devel@vger.kernel.org, linux-efi@vger.kernel.org,
devel@lists.orangefs.org, linux-kernel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-xfs@vger.kernel.org, linux-mm@kvack.org,
linux-nilfs@vger.kernel.org, linux-mtd@lists.infradead.org,
ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org,
linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 4/6] vfs: don't allow most setxattr to immutable files
Date: Thu, 20 Jun 2019 16:03:45 +0200 [thread overview]
Message-ID: <20190620140345.GI30243@quack2.suse.cz> (raw)
In-Reply-To: <156022840560.3227213.4776913678782966728.stgit@magnolia>
On Mon 10-06-19 21:46:45, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
>
> The chattr manpage has this to say about immutable files:
>
> "A file with the 'i' attribute cannot be modified: it cannot be deleted
> or renamed, no link can be created to this file, most of the file's
> metadata can not be modified, and the file can not be opened in write
> mode."
>
> However, we don't actually check the immutable flag in the setattr code,
> which means that we can update inode flags and project ids and extent
> size hints on supposedly immutable files. Therefore, reject setflags
> and fssetxattr calls on an immutable file if the file is immutable and
> will remain that way.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> fs/inode.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
>
> diff --git a/fs/inode.c b/fs/inode.c
> index a3757051fd55..adfb458bf533 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2184,6 +2184,17 @@ int vfs_ioc_setflags_check(struct inode *inode, int oldflags, int flags)
> !capable(CAP_LINUX_IMMUTABLE))
> return -EPERM;
>
> + /*
> + * We aren't allowed to change any other flags if the immutable flag is
> + * already set and is not being unset.
> + */
> + if ((oldflags & FS_IMMUTABLE_FL) &&
> + (flags & FS_IMMUTABLE_FL)) {
> + if ((oldflags & ~FS_IMMUTABLE_FL) !=
> + (flags & ~FS_IMMUTABLE_FL))
This check looks a bit strange when you've just check FS_IMMUTABLE_FL isn't
changing... Why not just oldflags != flags?
> + if ((old_fa->fsx_xflags & FS_XFLAG_IMMUTABLE) &&
> + (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)) {
> + if ((old_fa->fsx_xflags & ~FS_XFLAG_IMMUTABLE) !=
> + (fa->fsx_xflags & ~FS_XFLAG_IMMUTABLE))
Ditto here...
> + return -EPERM;
> + if (old_fa->fsx_projid != fa->fsx_projid)
> + return -EPERM;
> + if ((fa->fsx_xflags & (FS_XFLAG_EXTSIZE |
> + FS_XFLAG_EXTSZINHERIT)) &&
> + old_fa->fsx_extsize != fa->fsx_extsize)
> + return -EPERM;
> + if ((old_fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
> + old_fa->fsx_cowextsize != fa->fsx_cowextsize)
> + return -EPERM;
> + }
> +
> /* Extent size hints of zero turn off the flags. */
> if (fa->fsx_extsize == 0)
> fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-06-20 14:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 4:46 [PATCH v3 0/6] vfs: make immutable files actually immutable Darrick J. Wong
2019-06-11 4:46 ` [PATCH 1/6] mm/fs: don't allow writes to immutable files Darrick J. Wong
2019-06-20 21:52 ` Theodore Ts'o
2019-06-20 22:13 ` Darrick J. Wong
2019-06-21 0:54 ` Theodore Ts'o
2019-06-11 4:46 ` [PATCH 2/6] vfs: flush and wait for io when setting the immutable flag via SETFLAGS Darrick J. Wong
2019-06-20 14:00 ` Jan Kara
2019-06-20 22:09 ` Darrick J. Wong
2019-06-11 4:46 ` [PATCH 3/6] vfs: flush and wait for io when setting the immutable flag via FSSETXATTR Darrick J. Wong
2019-06-11 4:46 ` [PATCH 4/6] vfs: don't allow most setxattr to immutable files Darrick J. Wong
2019-06-20 14:03 ` Jan Kara [this message]
2019-06-20 21:36 ` Darrick J. Wong
2019-06-11 4:46 ` [PATCH 5/6] xfs: refactor setflags to use setattr code directly Darrick J. Wong
2019-06-11 4:47 ` [PATCH 6/6] xfs: clean up xfs_merge_ioc_xflags Darrick J. Wong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190620140345.GI30243@quack2.suse.cz \
--to=jack@suse.cz \
--cc=adilger.kernel@dilger.ca \
--cc=ard.biesheuvel@linaro.org \
--cc=clm@fb.com \
--cc=darrick.wong@oracle.com \
--cc=devel@lists.orangefs.org \
--cc=dsterba@suse.com \
--cc=jack@suse.com \
--cc=jaegeuk@kernel.org \
--cc=jk@ozlabs.org \
--cc=josef@toxicpanda.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-efi@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-f2fs-devel@lists.sourceforge.net \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-mtd@lists.infradead.org \
--cc=linux-nilfs@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=matthew.garrett@nebula.com \
--cc=ocfs2-devel@oss.oracle.com \
--cc=reiserfs-devel@vger.kernel.org \
--cc=tytso@mit.edu \
--cc=viro@zeniv.linux.org.uk \
--cc=yuchao0@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).