[FFmpeg-devel] [BUG][PATCH] qdm2 fixes

Michael Niedermayer michaelni
Fri Jul 18 23:27:21 CEST 2008


On Fri, Jul 18, 2008 at 10:52:23PM +0200, Benjamin Larsson wrote:
> 1 static overrun and 1 null pointer dereference. They are small so I
> attached both. These will close Coverity bugs: 68 and 112. Regarding the
> overrun this will only make sure we don't over read. I don't know what
> the correct fix is. And this code is never run also.
> 
> MvH
> Benjamin Larsson

> Index: libavcodec/qdm2.c
> ===================================================================
> --- libavcodec/qdm2.c	(revision 14282)
> +++ libavcodec/qdm2.c	(working copy)
> @@ -1452,6 +1452,9 @@
>          max = min;
>  
>          /* check for errors (?) */
> +        if (!packet)
> +            return;
> +
>          if (i == 0 && (packet->type < 16 || packet->type >= 48 || fft_subpackets[packet->type - 16]))
>              return;
>  

ok


> Index: libavcodec/qdm2.c
> ===================================================================
> --- libavcodec/qdm2.c	(revision 14282)
> +++ libavcodec/qdm2.c	(working copy)
> @@ -704,7 +704,7 @@
>                          if (add4 < 0)
>                              add4 = 0;
>                      }
> -                    tmp = tone_level_idx[ch][sb][j + 1] * 2 - add4 - add3 - add2 - add1;
> +                    tmp = tone_level_idx[ch][sb][FFMAX(j + 1,63)] * 2 - add4 - add3 - add2 - add1;
>                      if (tmp < 0)
>                          tmp = 0;
>                      tone_level_idx_temp[ch][sb][j + 1] = tmp & 0xff;

isnt the last line writing out of the array?

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

If a bugfix only changes things apparently unrelated to the bug with no
further explanation, that is a good sign that the bugfix is wrong.
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