linux-kernel - Re: [PATCH] x86_64: test that userspace stack is in fact NX

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Message-ID: <ZRxr79i5PAXRXjqr@gmail.com>
Date:   Tue, 3 Oct 2023 21:30:55 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     Alexey Dobriyan <adobriyan@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] x86_64: test that userspace stack is in fact NX


* Ingo Molnar <mingo@...nel.org> wrote:

> Because not having NX in 2023 on any system that is threatened is a
> big security vulnerability in itself, and whether the vendor or owner
> intentionally did that or not doesn't really matter, and a failing
> kernel testcase will be the least of their problems.

BTW., it's also questionable whether the owner is *aware* of the fact that 
NX is not available: what if some kernel debug option cleared the NX flag, 
unintended, or there's some serious firmware bug?

However unlikely those situations might be, I think unconditionally warning 
about NX not available is a very 2023 thing to do.

Thanks,

	Ingo