[FFmpeg-devel] [PATCH] indeo3: add out-of-buffer write check

[Reimar Döffinger]

On 17 May 2011, at 22:30, Stefano Sabatini <stefano.sabatini-lala at poste.it> wrote:

> Prevent out-of-buffer reads. In particular fix smclocki32.avi.1.1
> crash, fix trac issue #114, roundup issue #1482.
> ---
> libavcodec/indeo3.c |    3 +++
> 1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/libavcodec/indeo3.c b/libavcodec/indeo3.c
> index fb33a7c..37124e4 100644
> --- a/libavcodec/indeo3.c
> +++ b/libavcodec/indeo3.c
> @@ -208,6 +208,7 @@ static void iv_Decode_Chunk(Indeo3DecodeContext *s,
>     int *width_tbl, width_tbl_arr[10];
>     const signed char *ref_vectors;
>     uint8_t *cur_frm_pos, *ref_frm_pos, *cp, *cp2;
> +    uint8_t *cur_end = cur + width*height + width;
>     uint32_t *cur_lp, *ref_lp;
>     const uint32_t *correction_lp[2], *correctionloworder_lp[2], *correctionhighorder_lp[2];
>     uint8_t *correction_type_sp[2];
> @@ -354,6 +355,8 @@ static void iv_Decode_Chunk(Indeo3DecodeContext *s,
>                             k = *buf1++;
>                             cur_lp = ((uint32_t *)cur_frm_pos) + width_tbl[lp2];
>                             ref_lp = ((uint32_t *)ref_frm_pos) + width_tbl[lp2];
> +                            if ((uint8_t *)cur_lp >= cur_end)
> +                                break;

Not sure it matters, but this could still overread with cur_lp == cur_end - 1