linux-kernel - Re: [PATCH 0/4] x86/module: Out-of-tree module decode and sanitize

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Message-ID: <20200407204823.GS2452@worktop.programming.kicks-ass.net>
Date:   Tue, 7 Apr 2020 22:48:23 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Andrew Cooper <andrew.cooper3@...rix.com>
Cc:     tglx@...utronix.de, linux-kernel@...r.kernel.org,
        hch@...radead.org, sean.j.christopherson@...el.com,
        mingo@...hat.com, bp@...en8.de, hpa@...or.com, x86@...nel.org,
        kenny@...ix.com, jeyu@...nel.org, rasmus.villemoes@...vas.dk,
        pbonzini@...hat.com, fenghua.yu@...el.com, xiaoyao.li@...el.com,
        nadav.amit@...il.com, thellstrom@...are.com, tony.luck@...el.com,
        rostedt@...dmis.org, gregkh@...uxfoundation.org, jannh@...gle.com,
        keescook@...omium.org, David.Laight@...lab.com,
        dcovelli@...are.com, mhiramat@...nel.org
Subject: Re: [PATCH 0/4] x86/module: Out-of-tree module decode and sanitize

On Tue, Apr 07, 2020 at 09:21:31PM +0100, Andrew Cooper wrote:
> > +	switch (insn->opcode.bytes[1]) {
> > +	case 0x00:
> > +		if (modrm_mod != 0x03)
> > +			break;
> > +
> 
> Apologies - missed this before.  LLDT and LTR can be encoded with a
> memory operand, so you need to drop the modrm_mod check to spot all
> instances.

I spotted the same, already fixed. Sorry for the mistake, reading opcode
tables it a pain at the best of times :/