On 2020-04-28, Mickaël Salaün <mic@xxxxxxxxxxx> wrote: > The goal of this patch series is to enable to control script execution > with interpreters help. A new RESOLVE_MAYEXEC flag, usable through > openat2(2), is added to enable userspace script interpreter to delegate > to the kernel (and thus the system security policy) the permission to > interpret/execute scripts or other files containing what can be seen as > commands. > > This third patch series mainly differ from the previous one by relying > on the new openat2(2) system call to get rid of the undefined behavior > of the open(2) flags. Thus, the previous O_MAYEXEC flag is now replaced > with the new RESOLVE_MAYEXEC flag and benefits from the openat2(2) > strict check of this kind of flags. My only strong upfront objection is with this being a RESOLVE_ flag. RESOLVE_ flags have a specific meaning (they generally apply to all components, and affect the rules of path resolution). RESOLVE_MAYEXEC does neither of these things and so seems out of place among the other RESOLVE_ flags. I would argue this should be an O_ flag, but not supported for the old-style open(2). This is what the O_SPECIFIC_FD patchset does[1] and I think it's a reasonable way of solving such problems. -- Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH <https://www.cyphar.com/>
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