Linux Documentation
 help / color / mirror / Atom feed
From: Florian Weimer <fw@deneb.enyo.de>
To: Sasha Levin <sashal@kernel.org>
Cc: corbet@lwn.net,  akpm@linux-foundation.org,
	 skhan@linuxfoundation.org, linux-doc@vger.kernel.org,
	 linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	 gregkh@linuxfoundation.org
Subject: Re: [PATCH v2] killswitch: add per-function short-circuit mitigation primitive
Date: Sat, 09 May 2026 14:02:24 +0200	[thread overview]
Message-ID: <87ecjku6y7.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20260508195749.1885522-1-sashal@kernel.org> (Sasha Levin's message of "Fri, 8 May 2026 15:57:48 -0400")

* Sasha Levin:

> When a kernel (security) issue goes public, fleets stay exposed until a patched
> kernel is built, distributed, and rebooted into.
>
> For many such issues the simplest mitigation is to stop calling the buggy
> function. Killswitch provides that. An admin writes:
>
>     echo "engage af_alg_sendmsg -1" \
>         > /sys/kernel/security/killswitch/control
>
> After this, af_alg_sendmsg() returns -EPERM on every call without
> running its body. The mitigation takes effect immediately, and is dropped on
> the next reboot -- by which point a patched kernel is hopefully in place.

Do you expect this to be safe to enable in kernel lockdown mode (i.e.,
with typical Secure Boot configurations in distributions)?

  reply	other threads:[~2026-05-09 12:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-08 19:57 [PATCH v2] killswitch: add per-function short-circuit mitigation primitive Sasha Levin
2026-05-09 12:02 ` Florian Weimer [this message]
2026-05-09 12:34   ` Sasha Levin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87ecjku6y7.fsf@mid.deneb.enyo.de \
    --to=fw@deneb.enyo.de \
    --cc=akpm@linux-foundation.org \
    --cc=corbet@lwn.net \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=sashal@kernel.org \
    --cc=skhan@linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox