linux-kernel - Re: [PATCH] lib/vsprintf: make-printk-non-secret printks all addresses as unhashed

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Message-ID: <20210204204835.GA7529@amd>
Date:   Thu, 4 Feb 2021 21:48:35 +0100
From:   Pavel Machek <pavel@....cz>
To:     Timur Tabi <timur@...nel.org>
Cc:     Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        willy@...radead.org, akpm@...ux-foundation.org,
        torvalds@...ux-foundation.org, roman.fietze@...na.com,
        keescook@...omium.org, john.ogness@...utronix.de,
        akinobu.mita@...il.com
Subject: Re: [PATCH] lib/vsprintf: make-printk-non-secret printks all
 addresses as unhashed

On Tue 2021-02-02 14:18:46, Timur Tabi wrote:
> If the make-printk-non-secret command-line parameter is set, then
> printk("%p") will print addresses as unhashed.  This is useful for
> debugging purposes.
> 
> A large warning message is displayed if this option is enabled,
> because unhashed addresses, while useful for debugging, exposes
> kernel addresses which can be a security risk.

Yes please. I needed to see pointers for debugging, and seeing hashed
pointers is nasty. Having to patch C code to be able to develop... is
bad.

> +	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.

									Pavel
-- 
http://www.livejournal.com/~pavelmachek

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