draw: don't crash on vertex buffer overflow

We would crash when stride was bigger than the size of the buffer.
The correct behavior is to just fetch zero's in this case.
Unfortunatly with user_buffer's there's no way to validate the size
because currently we're just not getting it. Adjust the draw interface
to pass the size along the mapped buffer, which works perfectly
for buffer backed vertex_buffers and, in future, it will allow
us to plumb user_buffer sizes through the same interface.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/src/gallium/auxiliary/draw/draw_context.c b/src/gallium/auxiliary/draw/draw_context.c
index 6caa62ab31b..4eb1919b871 100644
--- a/src/gallium/auxiliary/draw/draw_context.c
+++ b/src/gallium/auxiliary/draw/draw_context.c
@@ -364,9 +364,11 @@ draw_set_vertex_elements(struct draw_context *draw,
  */
 void
 draw_set_mapped_vertex_buffer(struct draw_context *draw,
-                              unsigned attr, const void *buffer)
+                              unsigned attr, const void *buffer,
+                              size_t size)
 {
-   draw->pt.user.vbuffer[attr] = buffer;
+   draw->pt.user.vbuffer[attr].map  = buffer;
+   draw->pt.user.vbuffer[attr].size = size;
 }