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Message-ID: <2bcffc9f-9244-0362-2da9-ece230055320@intel.com>
Date:   Mon, 15 May 2023 07:28:29 -0700
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Subject: Re: [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1
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To:     jeffxu@chromium.org, luto@kernel.org, jorgelo@chromium.org,
        keescook@chromium.org, groeck@chromium.org, jannh@google.com,
        sroettger@google.com
Cc:     akpm@linux-foundation.org, jeffxu@google.com,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-mm@kvack.org, linux-hardening@vger.kernel.org
References: <20230515130553.2311248-1-jeffxu@chromium.org>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <20230515130553.2311248-1-jeffxu@chromium.org>
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On 5/15/23 06:05, jeffxu@chromium.org wrote:
> We're using PKU for in-process isolation to enforce control-flow integrity
> for a JIT compiler. In our threat model, an attacker exploits a 
> vulnerability and has arbitrary read/write access to the whole process
> space concurrently to other threads being executed. This attacker can
> manipulate some arguments to syscalls from some threads.

This all sounds like it hinges on the contents of PKRU in the attacker
thread.

Could you talk a bit about how the attacker is prevented from running
WRPKRU, XRSTOR or compelling the kernel to write to PKRU like at sigreturn?