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From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Florian Weimer <fw@deneb.enyo.de>,
	linux-xfs@vger.kernel.org, libc-alpha@sourceware.org,
	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk
Subject: Re: XFS reports lchmod failure, but changes file system contents
Date: Wed, 12 Feb 2020 10:11:28 -0800	[thread overview]
Message-ID: <20200212181128.GA31394@infradead.org> (raw)
In-Reply-To: <20200212161604.GP6870@magnolia>

On Wed, Feb 12, 2020 at 08:16:04AM -0800, Darrick J. Wong wrote:
> xfs_setattr_nonsize calls posix_acl_chmod which returns EOPNOTSUPP
> because the xfs symlink inode_operations do not include a ->set_acl
> pointer.
> 
> I /think/ that posix_acl_chmod code exists to enforce that the file mode
> reflects any acl that might be set on the inode, but in this case the
> inode is a symbolic link.
> 
> I don't remember off the top of my head if ACLs are supposed to apply to
> symlinks, but what do you think about adding get_acl/set_acl pointers to
> xfs_symlink_inode_operations and xfs_inline_symlink_inode_operations ?

Symlinks don't have permissions or ACLs, so adding them makes no
sense.

xfs doesn't seem all that different from the other file systems,
so I suspect you'll also see it with other on-disk file systems.
We probably need a check high up in the chmod and co code to reject
the operation early for O_PATH file descriptors pointing to symlinks.

  reply	other threads:[~2020-02-12 18:11 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12 11:48 XFS reports lchmod failure, but changes file system contents Florian Weimer
2020-02-12 12:15 ` Florian Weimer
2020-02-12 16:16 ` Darrick J. Wong
2020-02-12 18:11   ` Christoph Hellwig [this message]
2020-02-12 18:37     ` Darrick J. Wong
2020-02-12 19:15       ` Florian Weimer
2020-02-12 19:51         ` Al Viro
2020-02-12 19:55           ` Rich Felker
2020-02-12 20:01           ` Florian Weimer
2020-02-12 20:17             ` Andreas Schwab
2020-02-12 20:19               ` Rich Felker
2020-02-12 20:26                 ` Florian Weimer
2020-02-12 20:38                   ` Rich Felker
2020-02-12 20:27                 ` Al Viro
2020-02-12 20:36                   ` Rich Felker
2020-02-12 20:18             ` Rich Felker
2020-02-12 20:38             ` Paul Eggert
2020-02-21  4:09             ` Aleksa Sarai
2020-02-21  5:02               ` Al Viro
2020-02-21  5:21                 ` Aleksa Sarai
2020-02-12 18:50     ` Florian Weimer
2020-02-12 18:55       ` Christoph Hellwig

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