[PATCH 3/5] usp10: Range check glyph counts in GPOS_apply_ContextPos().

[Aric Stewart]

Signed-off-by: Aric Stewart <aric at codeweavers.com>

On 4/17/17 1:26 PM, Henri Verbeet wrote:
> Signed-off-by: Henri Verbeet <hverbeet at codeweavers.com>
> ---
>  dlls/usp10/opentype.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/dlls/usp10/opentype.c b/dlls/usp10/opentype.c
> index 2cca0cb..ec425a1 100644
> --- a/dlls/usp10/opentype.c
> +++ b/dlls/usp10/opentype.c
> @@ -2166,12 +2166,18 @@ static unsigned int GPOS_apply_ContextPos(const ScriptCache *script_cache, const
>                  {
>                      const GPOS_PosClassRule_1 *pr;
>                      const GPOS_PosClassRule_2 *pr_2;
> +                    unsigned int g;
>                      int g_count, l;
>  
>                      offset = GET_BE_WORD(pcs->PosClassRule[k]);
>                      pr = (const GPOS_PosClassRule_1*)((const BYTE*)pcs+offset);
>                      g_count = GET_BE_WORD(pr->GlyphCount);
>                      TRACE("PosClassRule has %i glyphs classes\n",g_count);
> +
> +                    g = glyph_index + write_dir * (g_count - 1);
> +                    if (g >= glyph_count)
> +                        continue;
> +
>                      for (l = 0; l < g_count-1; l++)
>                      {
>                          int g_class = OT_get_glyph_class(glyph_class_table, glyphs[glyph_index + (write_dir * (l+1))]);
>