From: Pavel Machek <pavel@ucw.cz>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Timur Tabi <timur@kernel.org>, Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
willy@infradead.org, akpm@linux-foundation.org,
torvalds@linux-foundation.org, roman.fietze@magna.com,
keescook@chromium.org, john.ogness@linutronix.de,
akinobu.mita@gmail.com
Subject: Re: [PATCH] lib/vsprintf: make-printk-non-secret printks all addresses as unhashed
Date: Thu, 4 Feb 2021 22:49:44 +0100 [thread overview]
Message-ID: <20210204214944.GA13103@amd> (raw)
In-Reply-To: <20210204155423.2864bf4f@gandalf.local.home>
[-- Attachment #1: Type: text/plain, Size: 1715 bytes --]
Hi!
> Pavel Machek <pavel@ucw.cz> wrote:
>
> > > + pr_warn("** Kernel memory addresses are exposed, which may **\n");
> > > + pr_warn("** compromise security on your system. **\n");
> >
> > This is lies, right? And way too verbose.
>
> Not really. More of an exaggeration than a lie. And the verbosity is
> to
Well... security is _not_ compromised but robustness against kernel
bugs is reduced. It should not exaggerate.
> make sure it's noticed by those that shouldn't have it set. This works well
> for keeping trace_printk() out of production kernels. Why do you
> care
So if we want people to see it, we up the severity, right? Like
pr_err()... Distro kernels have quiet, anyway...
Lets take a look for what we say for _real_ problems:
[ 0.544757] Spectre V1 : Mitigation: usercopy/swapgs barriers and
__user pointer sanitiza
tion
[ 0.544876] Spectre V2 : Mitigation: Full generic retpoline
[ 0.544961] Spectre V2 : Spectre v2 / SpectreRSB mitigation:
Filling RSB on context switc
h
[ 0.545064] L1TF: System has more than MAX_PA/2 memory. L1TF
mitigation not effective.
[ 0.545163] L1TF: You may make it effective by booting the kernel
with mem=2147483648 par
ameter.
[ 0.545281] L1TF: However, doing so will make a part of your RAM
unusable.
[ 0.545374] L1TF: Reading
https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html
might help you decide.
This machine is insecure. Yet I don't see ascii-art *** all around..
"Kernel memory addresses are exposed, which is bad for security."
would be quite enough, I'd say...
Best regards,
Pavel
--
http://www.livejournal.com/~pavelmachek
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
next prev parent reply other threads:[~2021-02-04 21:49 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 20:18 [PATCH] lib/vsprintf: make-printk-non-secret printks all addresses as unhashed Timur Tabi
2021-02-02 21:52 ` Kees Cook
2021-02-02 22:19 ` Timur Tabi
2021-02-02 22:34 ` Steven Rostedt
2021-02-02 22:51 ` Linus Torvalds
2021-02-03 18:53 ` Kees Cook
2021-02-04 20:48 ` Pavel Machek
2021-02-04 20:54 ` Steven Rostedt
2021-02-04 21:49 ` Pavel Machek [this message]
2021-02-04 21:59 ` Timur Tabi
2021-02-04 22:06 ` Steven Rostedt
2021-02-04 22:11 ` Pavel Machek
2021-02-04 22:17 ` Kees Cook
2021-02-04 22:20 ` Timur Tabi
2021-02-04 22:51 ` Pavel Machek
2021-02-04 22:57 ` Pavel Machek
2021-02-04 22:05 ` Steven Rostedt
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=20210204214944.GA13103@amd \
--to=pavel@ucw.cz \
--cc=akinobu.mita@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=john.ogness@linutronix.de \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=pmladek@suse.com \
--cc=roman.fietze@magna.com \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky@gmail.com \
--cc=timur@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=willy@infradead.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.