linux-kernel - Re: [PATCH 2/3] lib/vsprintf: Hash legacy clock addresses

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Message-ID: <20181009140540.mz77x5a7bfmupxbb@pathway.suse.cz>
Date:   Tue, 9 Oct 2018 16:05:40 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Geert Uytterhoeven <geert+renesas@...der.be>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        "Tobin C . Harding" <me@...in.cc>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jonathan Corbet <corbet@....net>, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org
Subject: Re: [PATCH 2/3] lib/vsprintf: Hash legacy clock addresses

On Mon 2018-10-08 13:05:03, Geert Uytterhoeven wrote:
> On platforms using the Common Clock Framework, "%pC" prints the clock's
> name. On legacy platforms, it prints the unhashed clock's address,
> potentially leaking sensitive information regarding the kernel layout in
> memory.
> 
> Avoid this leak by printing the hashed address instead.  To distinguish
> between clocks, a 32-bit unique identifier is as good as an actual
> pointer value.
> 
> Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>

It makes sense.

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr