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Re: /proc filesystem allows bypassing directory permissions on Linux

On 26.10.2009 18:14, nomail@xxxxxxxxxx wrote:
I do not think mounting /proc should change access control semantics.

It didn't in fact change anything. If the guest created hardlink to that file in
>> a unrestricted location, what would you say?

Do your homework and test it. You can't create the hardlink - the link(oldpath,
> newpath) call will fail with EACCES if search permission is denied for any
> directory in oldpath or newpath. Documented in the manpage, and I just tested
> and verified it.

Good boy. However, there wasn't worth both citing well known facts to me and testing them. Remember the scenario from the original mail and try finding a window, during which creating a hardlink would still work thus evading directory permissions check.

Sincerely Your, Dan.