static void g2m_paint_cursor(G2MContext *c, uint8_t *dst, int stride)
{
    int i, j;
    int x, y, w, h;
    const uint8_t *cursor;

    if (!c->cursor)
        return;

    x = c->cursor_x - c->cursor_hot_x;
    y = c->cursor_y - c->cursor_hot_y;

    cursor = c->cursor;
    w      = c->cursor_w;
    h      = c->cursor_h;

    if (x + w > c->width)
        w = c->width - x;
    if (y + h > c->height)
        h = c->height - y;
    if (x < 0) {
        w      +=  x;
        cursor += -x * 4;
    } else {
        dst    +=  x * 3;
    }
    if (y < 0) {
        h      +=  y;
        cursor += -y * c->cursor_stride;
    } else {
        dst    +=  y * stride;
    }
    if (w < 0 || h < 0)
        return;

    for (j = 0; j < h; j++) {
        for (i = 0; i < w; i++) {
            uint8_t alpha = cursor[i * 4];
            APPLY_ALPHA(dst[i * 3 + 0], cursor[i * 4 + 1], alpha);
            APPLY_ALPHA(dst[i * 3 + 1], cursor[i * 4 + 2], alpha);
            APPLY_ALPHA(dst[i * 3 + 2], cursor[i * 4 + 3], alpha);
        }
        dst    += stride;
        cursor += c->cursor_stride;
    }
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.