*thread necromancy* On Tue, Apr 05, 2022 at 06:09:03PM +0200, Mickaël Salaün wrote: > > On 05/04/2022 01:26, Linus Torvalds wrote: > > On Mon, Apr 4, 2022 at 3:25 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > [...] > > > > > > I think this already exists as AT_EACCESS? It was added with > > > faccessat2() itself, if I'm reading the history correctly. > > > > Yeah, I noticed myself, I just hadn't looked (and I don't do enough > > user-space programming to be aware of if that way). > > I think AT_EACCESS should be usable with the new EXECVE_OK too. > > > > > > > > (a) "what about suid bits that user space cannot react to" > > > > > > What do you mean here? Do you mean setid bits on the file itself? > > > > Right. > > > > Maybe we don't care. > > I think we don't. I think the only corner case that could be different is > for files that are executable, SUID and non-readable. In this case it > wouldn't matter because userspace could not read the file, which is required > for interpretation/execution. Anyway, S[GU]ID bits in scripts are just > ignored by execve and we want to follow the same semantic. Hi Mickaël, Is there a new version of this being worked on? It would be really nice to have the O_MAYEXEC/faccessat2() visibility for script execution control in userspace. It seems like it would be mainly a respin of an earlier version of this series before trusted_for() was proposed. -Kees -- Kees Cook
