[FFmpeg-devel] [PATCH] pnmdec: make sure v is capped by maxval

[Michael Niedermayer]

On Wed, Nov 09, 2016 at 01:11:29AM +0100, Andreas Cadhalpun wrote:
> Otherwise put_bits can be called with a value that doesn't fit in the
> sample_len, causing an assertion failure.
> ---
>  libavcodec/pnmdec.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/libavcodec/pnmdec.c b/libavcodec/pnmdec.c
> index ca97cc3..0381ea6 100644
> --- a/libavcodec/pnmdec.c
> +++ b/libavcodec/pnmdec.c
> @@ -145,6 +145,10 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
>                          /* read a sequence of digits */
>                          do {
>                              v = 10*v + c;
> +                             if (v > s->maxval) {
> +                                av_log(avctx, AV_LOG_ERROR, "value %d larger than maxval %d\n", v, s->maxval);
> +                                return AVERROR_INVALIDDATA;
> +                            }

indention is a bit noisy

i think it can overflow if maxval is large,
it would be faster to check outside the loop

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I do not agree with what you have to say, but I'll defend to the death your
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