draw: try to prevent overflows on index buffers

Pass in the size of the index buffer, when available, and use it
to handle out of bounds conditions. The behavior in the case of
an overflow needs to be the same as with other overflows in the
vertex processing pipeline meaning that a vertex should still
be generated but all attributes in it set to zero.

Signed-off-by: Zack Rusin <[email protected]>
Reviewed-by: José Fonseca <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>

1 files changed, 5 insertions, 4 deletions

diff --git a/src/gallium/auxiliary/draw/draw_pt.c b/src/gallium/auxiliary/draw/draw_pt.c
index a797d65de8c..14dde67b24c 100644
--- a/src/gallium/auxiliary/draw/draw_pt.c
+++ b/src/gallium/auxiliary/draw/draw_pt.c
@@ -339,7 +339,7 @@ draw_print_arrays(struct draw_context *draw, uint prim, int start, uint count)
 #define PRIM_RESTART_LOOP(elements) \
    do { \
       for (i = start; i < end; i++) { \
-         if (elements[i] == info->restart_index) { \
+         if (i < elt_max && elements[i] == info->restart_index) { \
             if (cur_count > 0) { \
                /* draw elts up to prev pos */ \
                draw_pt_arrays(draw, prim, cur_start, cur_count); \
@@ -371,6 +371,7 @@ draw_pt_arrays_restart(struct draw_context *draw,
    const unsigned start = info->start;
    const unsigned count = info->count;
    const unsigned end = start + count;
+   const unsigned elt_max = draw->pt.user.eltMax;
    unsigned i, cur_start, cur_count;
 
    assert(info->primitive_restart);
@@ -496,7 +497,7 @@ draw_vbo(struct draw_context *draw,
    assert(info->instance_count > 0);
    if (info->indexed)
       assert(draw->pt.user.elts);
-   
+
    count = info->count;
 
    draw->pt.user.eltBias = info->index_bias;
@@ -506,7 +507,7 @@ draw_vbo(struct draw_context *draw,
 
    if (0)
       debug_printf("draw_vbo(mode=%u start=%u count=%u):\n",
-                   info->mode, info->start, info->count);
+                   info->mode, info->start, count);
 
    if (0)
       tgsi_dump(draw->vs.vertex_shader->state.tokens, 0);
@@ -534,7 +535,7 @@ draw_vbo(struct draw_context *draw,
    }
 
    if (0)
-      draw_print_arrays(draw, info->mode, info->start, MIN2(info->count, 20));
+      draw_print_arrays(draw, info->mode, info->start, MIN2(count, 20));
 
    index_limit = util_draw_max_index(draw->pt.vertex_buffer,
                                      draw->pt.vertex_element,