[FFmpeg-devel] [PATCH] avcodec/webp: validate the distance prefix code

[Michael Niedermayer]

On Mon, Mar 02, 2015 at 08:58:45PM +0100, Andreas Cadhalpun wrote:
> Hi,
> 
> according to the WebP Lossless Bitstream Specification [1] the
> highest allowed value for the prefix code is 39. Attached patch adds
> a check for this to avoid crashes decoding broken files.
> 
> Best regards,
> Andreas
> 
> 
> 1: https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification#4_image_data
> 

>  webp.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 43adf54378f715b26fd69e5e9e7919707e51ae66  0001-avcodec-webp-validate-the-distance-prefix-code.patch
> From a33b82acc6ab16e1aafaa44d3258d5177dff2cb0 Mon Sep 17 00:00:00 2001
> From: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
> Date: Mon, 2 Mar 2015 20:47:57 +0100
> Subject: [PATCH] avcodec/webp: validate the distance prefix code
> 
> According to the WebP Lossless Bitstream Specification the highest
> allowed value for a prefix code is 39.
> 
> If prefix_code is too large, the calculated extra_bits has an invalid
> value and triggers an assertion in get_bits.

applied

thanks

[...]

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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Freedom in capitalist society always remains about the same as it was in
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