Re: [PATCH v2] exec: load_script: Allow interpreter argument truncation

From: Kees Cook
Date: Thu Feb 14 2019 - 13:10:42 EST

On Thu, Feb 14, 2019 at 9:59 AM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Feb 14, 2019 at 8:43 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> >
> > This documents the parsing steps, and will fail to exec if the string was
> > truncated with neither an end-of-line nor any trailing whitespace.
> Is there any reason why we don't just revert 8099b047ecc4 ("exec:
> load_script: don't blindly truncate shebang string").
> That revert patch would seem to be much simpler than this rather
> complicated thing.

We certainly can, but we'll still need to fix the "don't exec a
truncated interpreter path" problem (which this fixes).

I'm happy to do it as two steps instead: revert, then a separate fix
to land in the merge window?

Kees Cook