linux-kernel - Re: [PATCH] x86: add hintable NOPs emulation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3db7d599-c2a7-4bec-94b1-4872649dde8d@orca.pet>
Date: Wed, 20 Aug 2025 12:01:30 +0200
From: Marcos Del Sol Vives <marcos@...a.pet>
To: Borislav Petkov <bp@...en8.de>
Cc: "Ahmed S. Darwish" <darwi@...utronix.de>, linux-kernel@...r.kernel.org,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
 "H. Peter Anvin" <hpa@...or.com>, Brian Gerst <brgerst@...il.com>,
 Uros Bizjak <ubizjak@...il.com>, Ard Biesheuvel <ardb@...nel.org>,
 David Kaplan <david.kaplan@....com>, Kees Cook <kees@...nel.org>,
 "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Andrew Cooper <andrew.cooper3@...rix.com>, Oleg Nesterov <oleg@...hat.com>,
 "Xin Li (Intel)" <xin@...or.com>, Sabyrzhan Tasbolatov <snovitoll@...il.com>
Subject: Re: [PATCH] x86: add hintable NOPs emulation

El 20/08/2025 a las 11:55, Borislav Petkov escribió:
> On Wed, Aug 20, 2025 at 11:51:27AM +0200, Marcos Del Sol Vives wrote:
>> I mean, they should know what they need to recompile if they want to, not
>> just that their machine is having a bug triggered by some binary.
> 
> And what's stopping you from writing a proper error message explaining that?
> 
> And issuing that error message *exactly once* instead of flooding dmesg for no
> good reason?

Please define "once". Once per what? Per boot? Per executable? Per process?

Once per boot would mean they'd need to reboot to see if any other executables
are affected. Per executable AFAIK there are no facilities to do that, and the
closest is per process which is what it's currently being done (again, like
IOPL emulation which was already deemed okay a couple years ago and merged
into the kernel)