Re: [6.8-rc1 Regression] Unable to exec apparmor_parser from virt-aa-helper

[Linus Torvalds]

On Thu, 25 Jan 2024 at 06:17, Tetsuo Handa
<penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On 2024/01/25 3:27, Linus Torvalds wrote:
> > The whole cred use of current->in_execve in tomoyo should
> > *also* be fixed, but I didn't even try to follow what it actually
> > wanted.
>
> Due to TOMOYO's unique domain transition (transits to new domain before
> execve() succeeds and returns to old domain if execve() failed), TOMOYO
> depends on a tricky ordering shown below.

Ok, that doesn't really clarify anything for me.

I'm less interested in what the call paths are, and more like "_Why_
is all this needed for tomoyo?"

Why doesn't tomoyo just install the new cred at "commit_creds()" time?

(The security hooks that surround that  are
"->bprm_committing_creds()" and "->bprm_committed_creds()")

IOW, the whole "save things across two *independent* execve() calls"
seems crazy.

Very strange and confusing.

                    Linus