[opus] opus Digest, Vol 90, Issue 4

[Logan Stromberg]

 > I don't believe this is an actual error. If it's truly possible for
> these areas to overlap (I don't think it is), then something much more
> serious than using memmove instead of memcpy needs to be done about it.

In the C# version of this code, these two copy regions are stored in
separate arrays entirely. I agree that there should be no normal way to
have the memcpy overlap here (not excluding a malicious buffer overflow
attack or something). Does this patch demonstrably fix the bug cited
(1227580)?

On Tue, Jul 5, 2016 at 5:00 AM, <opus-request at xiph.org> wrote:

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> Today's Topics:
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>    1. [PATCH] SILK: use silk_memmove for potentially overlapping
>       areas (Tristan Matthews)
>    2. Re: [PATCH] SILK: use silk_memmove for potentially
>       overlapping areas (Timothy B. Terriberry)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon,  4 Jul 2016 09:18:12 -0400
> From: Tristan Matthews <tmatth at videolan.org>
> To: opus at xiph.org
> Cc: Tristan Matthews <tmatth at videolan.org>
> Subject: [opus] [PATCH] SILK: use silk_memmove for potentially
>         overlapping     areas
> Message-ID: <1467638292-19376-1-git-send-email-tmatth at videolan.org>
>
> Fixes CID 1227580
> ---
>  silk/process_NLSFs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/silk/process_NLSFs.c b/silk/process_NLSFs.c
> index c27cf03..d9123ef 100644
> --- a/silk/process_NLSFs.c
> +++ b/silk/process_NLSFs.c
> @@ -100,6 +100,6 @@ void silk_process_NLSFs(
>
>      } else {
>          /* Copy LPC coefficients for first half from second half */
> -        silk_memcpy( PredCoef_Q12[ 0 ], PredCoef_Q12[ 1 ],
> psEncC->predictLPCOrder * sizeof( opus_int16 ) );
> +        silk_memmove( PredCoef_Q12[ 0 ], PredCoef_Q12[ 1 ],
> psEncC->predictLPCOrder * sizeof( opus_int16 ) );
>      }
>  }
> --
> 2.8.1
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 04 Jul 2016 06:32:32 -0700
> From: "Timothy B. Terriberry" <tterribe at xiph.org>
> To: opus at xiph.org
> Subject: Re: [opus] [PATCH] SILK: use silk_memmove for potentially
>         overlapping areas
> Message-ID: <577A6570.4030802 at xiph.org>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> Tristan Matthews wrote:
> > Fixes CID 1227580
>
> I don't believe this is an actual error. If it's truly possible for
> these areas to overlap (I don't think it is), then something much more
> serious than using memmove instead of memcpy needs to be done about it.
>
>
> ------------------------------
>
> Subject: Digest Footer
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> ------------------------------
>
> End of opus Digest, Vol 90, Issue 4
> ***********************************
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