linux-kernel - Re: [PATCH] x86/microcode/AMD: fix read of uninitialized data

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Message-ID: <20180410142252.crnlqkia2pmucbum@mwanda>
Date:   Tue, 10 Apr 2018 17:22:53 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Borislav Petkov <bp@...en8.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/microcode/AMD: fix read of uninitialized data

On Tue, Apr 10, 2018 at 02:41:23PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> Currently function __load_ucode_amd can assign an uninitialized cp to *ret
> if get_builtin_microcode returns false.

What are you looking at?  Here is how it looks in linux-next:

   270  
   271          if (!get_builtin_microcode(&cp, x86_family(cpuid_1_eax)))
   272                  cp = find_microcode_in_initrd(path, use_pa);
   273  


If get_builtin_microcode() returns false, then cp is initialized on the
next line.

Maybe the issue is that cp.name is uninitialized.  It doesn't cause an
issue but it would be understandable for a static checker to warn about
it when we do "*ret = cp;".

regards,
dan carpenter