On Mon, May 08, 2017 at 12:17:53AM +0200, Jann Horn wrote:

On Sun, May 7, 2017 at 5:58 PM, Darrick J. Wong [off-list ref] wrote:

quoted

Document the new GETFSMAP ioctl that returns the physical layout of a
(disk-based) filesystem.

[...]

quoted

+.B EPERM
+This query is not allowed.

Please document the circumstances under which a query is allowed.

For the two current implementations, queries are always allowed.

(The doc could be more explicit about this decision being left to the
implementation.)

Also: From a quick glance at the XFS implementation, I don't see any
privilege checks. Am I missing something, or does this API permit an
unprivileged user to determine the number of physical blocks allocated
for any inode, even for inodes the user can't ordinarily see in any
way?

Correct.

--D

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