linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Matthew Wilcox <willy@infradead.org>
To: Timur Tabi <timur@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Petr Mladek <pmladek@suse.com>,
	roman.fietze@magna.com, keescook@chromium.org,
	Steven Rostedt <rostedt@goodmis.org>,
	John Ogness <john.ogness@linutronix.de>,
	linux-mm@kvack.org, Akinobu Mita <akinobu.mita@gmail.com>
Subject: Re: [PATCH 0/2] introduce DUMP_PREFIX_UNHASHED for hex dumps
Date: Mon, 18 Jan 2021 18:26:35 +0000	[thread overview]
Message-ID: <20210118182635.GD2260413@casper.infradead.org> (raw)
In-Reply-To: <20210116220950.47078-1-timur@kernel.org>

On Sat, Jan 16, 2021 at 04:09:48PM -0600, Timur Tabi wrote:
> First patch updates print_hex_dump() and related functions to
> allow callers to print hex dumps with unhashed addresses.  It
> adds a new prefix type, so existing code is unchanged.
> 
> Second patch changes a page poising function to use the new
> address type.  This is just an example of a change.  If it's
> wrong, it doesn't need to be applied.
> 
> IMHO, hashed addresses make very little sense for hex dumps,
> which print addresses in 16- or 32-byte increments.  Typical
> use-case is to correlate an addresses in between one of these
> increments with some other address, but that can't be done
> if the addresses are hashed.  I expect most developers to
> want to replace their usage of DUMP_PREFIX_ADDRESS with
> DUMP_PREFIX_UNHASHED, now that they have the opportunity.

Yes, I'm sure most kernel developers actually do want to leak kernel
addresses into kernel messages.  The important thing though is that it
should be hard for them to do that, and it should stick out like a sore
thumb if they do it.

Don't make it easy.  And don't make it look like they're doing
something innocent.  DUMP_PREFIX_SECURITY_HOLE would be OK
by me.  DUMP_PREFIX_LEAK_INFORMATION would work fine too.
DUMP_PREFIX_MAKE_ATTACKERS_LIFE_EASY might be a bit too far.

  parent reply	other threads:[~2021-01-18 18:46 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-16 22:09 [PATCH 0/2] introduce DUMP_PREFIX_UNHASHED for hex dumps Timur Tabi
2021-01-16 22:09 ` [PATCH 1/2] [v2] lib/hexdump: introduce DUMP_PREFIX_UNHASHED for unhashed addresses Timur Tabi
2021-01-18 10:03   ` Andy Shevchenko
2021-01-18 15:57     ` Timur Tabi
2021-01-18 17:14       ` Andy Shevchenko
2021-01-18 17:53         ` Timur Tabi
2021-01-16 22:09 ` [PATCH 2/2] mm/page_poison: use unhashed address in hexdump for check_poison_mem() Timur Tabi
2021-01-18 18:26 ` Matthew Wilcox [this message]
2021-01-18 19:03   ` [PATCH 0/2] introduce DUMP_PREFIX_UNHASHED for hex dumps Timur Tabi
2021-01-19  0:53     ` Sergey Senozhatsky
2021-01-19  1:47       ` Matthew Wilcox
2021-01-19 10:38         ` Sergey Senozhatsky
2021-01-19 19:45           ` Kees Cook
2021-01-26 16:47           ` Vlastimil Babka
2021-01-26 16:59             ` Timur Tabi
2021-01-26 17:14               ` Steven Rostedt
2021-01-26 17:14               ` Vlastimil Babka
2021-01-26 17:30                 ` Timur Tabi
2021-01-26 17:39                   ` Steven Rostedt
2021-01-26 17:40                     ` Steven Rostedt
2021-01-26 19:23                       ` John Ogness
2021-01-27  2:11                         ` Sergey Senozhatsky
2021-01-27  3:22                           ` Timur Tabi
2021-01-27 10:11                       ` Petr Mladek
2021-01-27 10:38                         ` Vlastimil Babka
2021-01-19 19:45         ` Kees Cook
2021-01-19 19:55           ` Timur Tabi
2021-01-19 20:10             ` Steven Rostedt
2021-01-19 20:49               ` Timur Tabi
2021-01-19 21:15                 ` Steven Rostedt
2021-01-19 21:25                   ` Timur Tabi
2021-01-20  9:19             ` Petr Mladek
2021-01-20 12:17               ` Matthew Wilcox
2021-01-20 19:39               ` Linus Torvalds
2021-01-19 20:18           ` Randy Dunlap
2021-01-20 20:28             ` Kees Cook
2021-01-19  2:30       ` Timur Tabi

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=20210118182635.GD2260413@casper.infradead.org \
    --to=willy@infradead.org \
    --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 \
    /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;
as well as URLs for NNTP newsgroup(s).