Re: [PATCH 3/3] [v3] lib/vsprintf: debug_never_hash_pointers prints all addresses as unhashed

From: Timur Tabi <timur@kernel.org>
To: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Matthew Wilcox <willy@infradead.org>,
	akpm@linux-foundation.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	roman.fietze@magna.com, Kees Cook <keescook@chromium.org>,
	John Ogness <john.ogness@linutronix.de>,
	akinobu.mita@gmail.com, glider@google.com,
	Andrey Konovalov <andreyknvl@google.com>,
	Marco Elver <elver@google.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Pavel Machek <pavel@ucw.cz>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 3/3] [v3] lib/vsprintf: debug_never_hash_pointers prints all addresses as unhashed
Date: Thu, 11 Feb 2021 12:16:55 -0600	[thread overview]
Message-ID: <4a233bef-8ba6-82bb-9075-35793a244a3b@kernel.org> (raw)
In-Reply-To: <YCVvB7skjoN18HKO@alley>

On 2/11/21 11:53 AM, Petr Mladek wrote:
> I would really like to make it clear here that it is not only about
> consoles. Most people will see only this message. Only few people read
> documentation. Many people will learn the parameter name from another
> context by googling.
> 
> I know that it is not easy to find good words. Especially because
> pointers printed by %pK might still be hashed.
> 
>> +	pr_warn("**                                                      **\n");
>> +	pr_warn("** Kernel memory addresses are exposed, which may       **\n");
>> +	pr_warn("** reduce the security of your system.                  **\n");

> What about replacing the first two paragraphs with something like:
> 
> "This system shows unhashed kernel memory addresses via logs and
>   other interfaces. It might reduce the security of your system."

That works, thanks.  I'll post a v4 soon.