From: Kees Cook <kees@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Brendan Higgins <brendan.higgins@linux.dev>,
David Gow <david@davidgow.net>, Rae Moar <raemoar63@gmail.com>,
llvm@lists.linux.dev, kunit-dev@googlegroups.com,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] kunit: cfi: Add test for kCFI indirect-call type checks
Date: Fri, 19 Jun 2026 13:54:31 -0700 [thread overview]
Message-ID: <202606191351.0B1AC6650@keescook> (raw)
In-Reply-To: <202606191342.E2B47A5@keescook>
On Fri, Jun 19, 2026 at 01:44:43PM -0700, Kees Cook wrote:
> On Fri, Jun 19, 2026 at 11:51:29AM +0200, Peter Zijlstra wrote:
> > > This is really rather horrible. Also, now all an attacker needs to do is
> > > ensure cfi_kunit_handled() unconditionally returns true. IOW, no distro
> > > must ever have this KUNIT crap enabled.
> >
> > Also, if this lives, the check should at least trip the cfi_warn path,
> > being completely silent is terrible.
>
> If anyone actually ships kunit in production, then no, I will NAK my own
> patch. ;) In that case I will go back to a version I never sent, which
> uses Kunit's try/catch Oops checker (which doesn't work on riscv). I
> only did it this way (similar to the fortify kunit testing) so I could
> get riscv coverage.
Fedora and Android do appear to ship with CONFIG_KUNIT=m. Debian
and Ubuntu don't from what I can see.
So, yeah, NAK.
I'll send v3 (really v0)...
--
Kees Cook
next prev parent reply other threads:[~2026-06-19 20:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-18 21:09 [PATCH v2] kunit: cfi: Add test for kCFI indirect-call type checks Kees Cook
2026-06-19 9:37 ` Peter Zijlstra
2026-06-19 9:51 ` Peter Zijlstra
2026-06-19 20:44 ` Kees Cook
2026-06-19 20:54 ` Kees Cook [this message]
2026-06-19 20:42 ` Kees Cook
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