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From: Steven Rostedt <rostedt@goodmis.org>
To: Philipp Rudo <prudo@redhat.com>
Cc: Ricardo Ribalda <ribalda@chromium.org>,
	Eric Biederman <ebiederm@xmission.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
	Ross Zwisler <zwisler@kernel.org>,
	linux-doc@vger.kernel.org,
	"Joel Fernandes (Google)" <joel@joelfernandes.org>
Subject: Re: [PATCH v1 2/2] kexec: Introduce kexec_reboot_disabled
Date: Tue, 29 Nov 2022 09:32:45 -0500	[thread overview]
Message-ID: <20221129093245.599903e7@gandalf.local.home> (raw)
In-Reply-To: <20221129144450.75a7181e@rotkaeppchen>

On Tue, 29 Nov 2022 14:44:50 +0100
Philipp Rudo <prudo@redhat.com> wrote:

> An alternative approach and sort of compromise I see is to convert
> kexec_load_disabled from a simple on/off switch to a counter on how
> often a kexec load can be made (in practice a tristate on/off/one-shot
> should be sufficient). Ideally the reboot and panic path will
> have separate counters. With that you could for example use
> kexec_load_limit.reboot=0 and kexec_load_limit.panic=1 to disable the
> load of images for reboot while still allow to load a crash kernel
> once. With this you have the flexibility you need while also preventing
> a race where an attacker overwrites your crash kernel before you can
> toggle the switch. What do you think?

I actually like this idea :-)

-- Steve

WARNING: multiple messages have this Message-ID (diff)
From: Steven Rostedt <rostedt@goodmis.org>
To: Philipp Rudo <prudo@redhat.com>
Cc: Ricardo Ribalda <ribalda@chromium.org>,
	Eric Biederman <ebiederm@xmission.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
	Ross Zwisler <zwisler@kernel.org>,
	linux-doc@vger.kernel.org,
	"Joel Fernandes (Google)" <joel@joelfernandes.org>
Subject: Re: [PATCH v1 2/2] kexec: Introduce kexec_reboot_disabled
Date: Tue, 29 Nov 2022 09:32:45 -0500	[thread overview]
Message-ID: <20221129093245.599903e7@gandalf.local.home> (raw)
In-Reply-To: <20221129144450.75a7181e@rotkaeppchen>

On Tue, 29 Nov 2022 14:44:50 +0100
Philipp Rudo <prudo@redhat.com> wrote:

> An alternative approach and sort of compromise I see is to convert
> kexec_load_disabled from a simple on/off switch to a counter on how
> often a kexec load can be made (in practice a tristate on/off/one-shot
> should be sufficient). Ideally the reboot and panic path will
> have separate counters. With that you could for example use
> kexec_load_limit.reboot=0 and kexec_load_limit.panic=1 to disable the
> load of images for reboot while still allow to load a crash kernel
> once. With this you have the flexibility you need while also preventing
> a race where an attacker overwrites your crash kernel before you can
> toggle the switch. What do you think?

I actually like this idea :-)

-- Steve

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2022-11-29 14:33 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-14 13:18 [PATCH v1 0/2] kexec: Add new toogle to disable kexec_reboot Ricardo Ribalda
2022-11-14 13:18 ` Ricardo Ribalda
2022-11-14 13:18 ` [PATCH v1 1/2] Documentation: sysctl: Correct kexec_load_disabled Ricardo Ribalda
2022-11-14 13:18   ` Ricardo Ribalda
2022-11-23  9:47   ` Baoquan He
2022-11-23  9:47     ` Baoquan He
2022-11-14 13:18 ` [PATCH v1 2/2] kexec: Introduce kexec_reboot_disabled Ricardo Ribalda
2022-11-14 13:18   ` Ricardo Ribalda
2022-11-17 15:06   ` Philipp Rudo
2022-11-17 15:06     ` Philipp Rudo
2022-11-17 15:15     ` Ricardo Ribalda
2022-11-17 15:15       ` Ricardo Ribalda
2022-11-21 14:09       ` Philipp Rudo
2022-11-21 14:09         ` Philipp Rudo
2022-11-23  8:58         ` Ricardo Ribalda
2022-11-23  8:58           ` Ricardo Ribalda
2022-11-24 11:40           ` Philipp Rudo
2022-11-24 11:40             ` Philipp Rudo
2022-11-24 12:52             ` Ricardo Ribalda
2022-11-24 12:52               ` Ricardo Ribalda
2022-11-24 15:01               ` Philipp Rudo
2022-11-24 15:01                 ` Philipp Rudo
2022-11-24 22:32                 ` Ricardo Ribalda
2022-11-24 22:32                   ` Ricardo Ribalda
2022-11-28 16:28                   ` Philipp Rudo
2022-11-28 16:28                     ` Philipp Rudo
2022-11-28 23:37                     ` Steven Rostedt
2022-11-28 23:37                       ` Steven Rostedt
2022-11-28 16:42                 ` Steven Rostedt
2022-11-28 16:42                   ` Steven Rostedt
2022-11-29 13:44                   ` Philipp Rudo
2022-11-29 13:44                     ` Philipp Rudo
2022-11-29 14:32                     ` Steven Rostedt [this message]
2022-11-29 14:32                       ` Steven Rostedt
2022-12-12 21:43                       ` Ricardo Ribalda
2022-12-12 21:43                         ` Ricardo Ribalda
2022-11-23 13:49   ` Baoquan He
2022-11-23 13:49     ` Baoquan He

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