diff --git a/stb_image.h b/stb_image.h index 08020ac..d60371b 100644 --- a/stb_image.h +++ b/stb_image.h @@ -3267,6 +3267,13 @@ static int stbi__process_frame_header(stbi__jpeg *z, int scan) if (z->img_comp[i].v > v_max) v_max = z->img_comp[i].v; } + // check that plane subsampling factors are integer ratios; our resamplers can't deal with fractional ratios + // and I've never seen a non-corrupted JPEG file actually use them + for (i=0; i < s->img_n; ++i) { + if (h_max % z->img_comp[i].h != 0) return stbi__err("bad H","Corrupt JPEG"); + if (v_max % z->img_comp[i].v != 0) return stbi__err("bad V","Corrupt JPEG"); + } + // compute interleaved mcu info z->img_h_max = h_max; z->img_v_max = v_max;