[FFmpeg-devel] [PATCH] dvbsubdec: Avoid potential use of uninitialized memory

[Clément Bœsch]

On Mon, Sep 12, 2011 at 09:13:47PM +0200, Joakim Plate wrote:
> Another option would be to move these variables to context
> and remember them between each call to decode_dvd_subtitles
> ---
>  libavcodec/dvdsubdec.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

> diff --git a/libavcodec/dvdsubdec.c b/libavcodec/dvdsubdec.c
> index dcc5e6b..6325cce 100644
> --- a/libavcodec/dvdsubdec.c
> +++ b/libavcodec/dvdsubdec.c
> @@ -206,7 +206,7 @@ static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,
>      int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
>      int big_offsets, offset_size, is_8bit = 0;
>      const uint8_t *yuv_palette = 0;
> -    uint8_t colormap[4], alpha[256];
> +    uint8_t colormap[4] = {0}, alpha[256] = {0};
>      int date;
>      int i;
>      int is_menu = 0;

Mmh it seems I forgot to apply that patch when I proposed it a while ago.
IIRC, only colormap is concerned about the uninitialized values. Also,
Michael pointed out the zeros might not be a good fallback values…

-- 
Clément B.
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