Hi!

On Mon, Aug 07, 2023 at 11:41:48AM +0200, Mickaël Salaün wrote:

On Mon, Aug 07, 2023 at 09:39:50AM +0200, Günther Noack wrote:

quoted

We've already tested the inheritance of access rights across different
directories and mount points in other tests.  I feel that exercising it in all
combinations of access rights and inheritance mechanisms makes the tests harder
to understand and maintain, and does not give us much additional confidence on
top of what we already have.  What balance do you want to find there?

Indeed. It should be notted that this new IOCTL access right will be the
first one to directly apply to both files and directories.  It should
then have the same scope as LANDLOCK_ACCESS_FS_READ i.e., apply to the
target directory itself and files/directories beneath it.

We then need to test a directory's IOCTL, for instance using FIOQSIZE.

What about this two rules and related access checks, combined with
already-opened FD?
- dir_s1d1: always denied (negative test)
- file1_s1d1: allowed with a rule (checks ACCESS_FILE)
- dir_s2d1: allowed with a rule (checks directory right)

Ah, that's an excellent point - I had not realized yet that it is different to
the other access rights in that way, and it makes a lot of sense to test that. 👍

I'll dig up one IOCTL command for regular files and one IOCTL command for
directories like FIOQSIZE, which are both not blanket-permitted, and I'll test
it with that, and will make sure to cover the combinations you listed above.

Thanks!
—Günther

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