On Sat, Aug 24, 2024 at 5:13 AM Luis Chamberlain mcgrof@kernel.org wrote:
I'm all for this, however a strong rejection outright for the first kernel release is bound to end up with some angry user with some oddball driver that had this for whatever stupid reason.
I can't actually see a reason why a firmware file would have a ".." component in it, so I think the immediate rejection is fine - particularly since it has a warning printout, so you see what happened and why.
I do wonder if we should just have a LOOKUP_NO_DOTDOT flag, and just use that.
[ Christian - the issue is the firmware loading path not wanting to have ".." in the pathname so that you can't load outside the normal firmware tree. We could also use LOOKUP_BENEATH, except kernel_read_file_from_path_initns() just takes one long path rather than "here's the base, and here's the path". ]
There might be other people who want LOOKUP_NO_DOTDOT for similar reasons. In fact, some people might want an even stronger "normalized path" validation, where empty components or just "." is invalid, just because that makes pathnames ambiguous.
Linus