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 <zackr@vmware.com>
Reviewed-by: José Fonseca <jfonseca@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index 25a8ae6..84344c3 100644
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -67,6 +67,14 @@ struct draw_pt_front_end;
 
 
 /**
+ * Represents the mapped vertex buffer.
+ */
+struct draw_vertex_buffer {
+   const void *map;
+   size_t size;
+};
+
+/**
  * Basic vertex info.
  * Carry some useful information around with the vertices in the prim pipe.  
  */
@@ -183,7 +191,7 @@ struct draw_context
          unsigned max_index;
          
          /** vertex arrays */
-         const void *vbuffer[PIPE_MAX_ATTRIBS];
+         struct draw_vertex_buffer vbuffer[PIPE_MAX_ATTRIBS];
          
          /** constant buffers (for vertex/geometry shader) */
          const void *vs_constants[PIPE_MAX_CONSTANT_BUFFERS];