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From: Kees Cook <keescook@chromium.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>, Andy Lutomirski <luto@kernel.org>,
        David Howells <dhowells@redhat.com>, Serge Hallyn <serge@hallyn.com>,
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        Greg Ungerer <gerg@linux-m68k.org>, Ingo Molnar <mingo@kernel.org>,
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        linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov
Subject: [PATCH v2 0/8] exec: Use sane stack rlimit under secureexec
Date: Mon, 10 Jul 2017 00:57:23 -0700
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As discussed with Linus and Andy, we need to reset the stack rlimit
before we do memory layouts when execing a privilege-gaining (e.g.
setuid) program. This moves security_bprm_secureexec() earlier (with
required changes), and then lowers the stack limit when appropriate.

As a side-effect, dumpability and pdeath_signal clearing is expanded
to cover LSM definitions of secureexec (and Smack can drop its special
handler for pdeath_signal clearing).

I'd appreciate some extra eyes on this to make sure this isn't
broken in some special way. I couldn't find anything that _depended_
on security_bprm_secureexec() being called late.

Thanks!

-Kees

v2:
- fix missed current_security() uses in LSMs.
- research/consolidate dumpability setting logic
- research/consolidate pdeath_signal clearing logic
- split up logical steps a little more for easier review (and bisection)
- fix some old broken comments