From: Thomas Gleixner <tglx@linutronix.de>
To: Kees Cook <keescook@chromium.org>
Cc: Sami Tolvanen <samitolvanen@google.com>,
x86@kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Sedat Dilek <sedat.dilek@gmail.com>,
linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com
Subject: Re: [PATCH 06/15] x86: Avoid CFI jump tables in IDT and entry points
Date: Sat, 17 Apr 2021 02:02:31 +0200 [thread overview]
Message-ID: <87czutu6aw.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <202104161642.B72BD68@keescook>
On Fri, Apr 16 2021 at 16:56, Kees Cook wrote:
> On Sat, Apr 17, 2021 at 12:26:56AM +0200, Thomas Gleixner wrote:
>> Where is the analysis why excluding
>>
>> > +CFLAGS_REMOVE_idt.o := $(CC_FLAGS_CFI)
>> > +CFLAGS_REMOVE_paravirt.o := $(CC_FLAGS_CFI)
>>
>> all of idt.c and paravirt.c is correct and how that is going to be
>> correct in the future?
>>
>> These files are excluded from CFI, so I can add whatever I want to them
>> and circumvent the purpose of CFI, right?
>>
>> Brilliant plan that. But I know, sekurity ...
>
> *sigh* we're on the same side. :P I will choose to understand your
> comments here as:
>
> "How will enforcement of CFI policy be correctly maintained here if
> the justification for disabling it for whole compilation units is not
> clearly understandable by other developers not familiar with the nuances
> of its application?"
Plus, if there is a justification for disabling it for a whole
compilation unit:
Where is the tooling which makes sure that this compilation unit is not
later on filled with code which should be subject to CFI?
Thanks,
tglx
next prev parent reply other threads:[~2021-04-17 0:02 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 20:38 [PATCH 00/15] x86: Add support for Clang CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 01/15] objtool: Find a destination for jumps beyond the section end Sami Tolvanen
2021-04-20 18:14 ` Josh Poimboeuf
2021-04-20 20:25 ` Sami Tolvanen
2021-04-20 22:55 ` Josh Poimboeuf
2021-04-20 22:58 ` Nick Desaulniers
2021-04-16 20:38 ` [PATCH 02/15] objtool: Add CONFIG_CFI_CLANG support Sami Tolvanen
2021-04-20 19:47 ` Josh Poimboeuf
2021-04-20 20:45 ` Sami Tolvanen
2021-04-16 20:38 ` [PATCH 03/15] objtool: Add ASM_STACK_FRAME_NON_STANDARD Sami Tolvanen
2021-04-16 20:38 ` [PATCH 04/15] static_call: Use global functions for the self-test Sami Tolvanen
2021-04-16 21:37 ` Thomas Gleixner
2021-04-17 0:16 ` Thomas Gleixner
2021-04-16 20:38 ` [PATCH 05/15] x86: Implement function_nocfi Sami Tolvanen
2021-04-16 21:18 ` Borislav Petkov
2021-04-16 21:49 ` Sami Tolvanen
2021-04-16 22:02 ` Borislav Petkov
2021-04-16 22:06 ` Andy Lutomirski
2021-04-16 22:14 ` Borislav Petkov
2021-04-16 22:20 ` Andy Lutomirski
2021-04-16 22:37 ` Kees Cook
2021-04-16 23:02 ` Thomas Gleixner
2021-04-17 10:16 ` Thomas Gleixner
2021-04-19 15:13 ` Sami Tolvanen
2021-04-16 22:28 ` Kees Cook
2021-04-16 22:52 ` Andy Lutomirski
2021-04-16 22:58 ` Kees Cook
2021-04-16 23:40 ` Kees Cook
2021-04-17 23:19 ` Andy Lutomirski
2021-04-17 23:53 ` Thomas Gleixner
2021-04-18 0:11 ` Andy Lutomirski
2021-04-18 16:17 ` Thomas Gleixner
2021-04-18 22:57 ` Andy Lutomirski
2021-04-19 15:20 ` Sami Tolvanen
2021-04-19 15:26 ` David Laight
2021-04-19 17:46 ` Andy Lutomirski
2021-04-17 14:20 ` David Laight
2021-04-17 15:48 ` Andy Lutomirski
2021-04-19 8:40 ` Rasmus Villemoes
2021-04-19 16:45 ` Joao Moreira
2021-04-19 21:52 ` David Laight
2021-04-16 22:16 ` Kees Cook
2021-04-16 22:13 ` Thomas Gleixner
2021-04-16 20:38 ` [PATCH 06/15] x86: Avoid CFI jump tables in IDT and entry points Sami Tolvanen
2021-04-16 22:26 ` Thomas Gleixner
2021-04-16 23:56 ` Kees Cook
2021-04-17 0:02 ` Thomas Gleixner [this message]
2021-04-16 20:38 ` [PATCH 07/15] x86/ftrace: Use function_nocfi in MCOUNT_ADDR Sami Tolvanen
2021-04-16 20:38 ` [PATCH 08/15] x86/extable: Do not mark exception callback as CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 09/15] x86/alternatives: Use C int3 selftest but disable KASAN Sami Tolvanen
2021-04-17 11:37 ` Peter Zijlstra
2021-04-19 15:26 ` Sami Tolvanen
2021-04-20 7:19 ` Peter Zijlstra
2021-04-16 20:38 ` [PATCH 10/15] x86/purgatory: Disable CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 11/15] x86, relocs: Ignore __typeid__ relocations Sami Tolvanen
2021-04-16 20:38 ` [PATCH 12/15] x86, module: " Sami Tolvanen
2021-04-16 20:38 ` [PATCH 13/15] x86, cpu: Use LTO for cpu.c with CFI Sami Tolvanen
2021-04-16 20:38 ` [PATCH 14/15] x86, kprobes: Fix optprobe_template_func type mismatch Sami Tolvanen
2021-04-16 20:38 ` [PATCH 15/15] x86, build: Allow CONFIG_CFI_CLANG to be selected Sami Tolvanen
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