[Mesa-dev] [PATCH 2/2] st/mesa: Prevent huge lastlevel values from being computed.

[Stéphane Marchesin]

The current computation for the lastlevel is based on the level size and can
lead to writing past the end of the texture array. Instead we clamp according
to hardware limits.
---
 src/mesa/state_tracker/st_cb_texture.c |   28 +++++++++++++++++++++++++++-
 1 files changed, 27 insertions(+), 1 deletions(-)

diff --git a/src/mesa/state_tracker/st_cb_texture.c b/src/mesa/state_tracker/st_cb_texture.c
index ed3bbc7..51c76e3 100644
--- a/src/mesa/state_tracker/st_cb_texture.c
+++ b/src/mesa/state_tracker/st_cb_texture.c
@@ -67,6 +67,24 @@
 
 #define DBG if (0) printf
 
+static enum pipe_cap
+pipe_to_param(enum pipe_texture_target target)
+{
+   switch(target) {
+   case PIPE_TEXTURE_1D:
+   case PIPE_TEXTURE_2D:
+   case PIPE_TEXTURE_RECT:
+      return PIPE_CAP_MAX_TEXTURE_2D_LEVELS;
+   case PIPE_TEXTURE_3D:
+   case PIPE_TEXTURE_2D_ARRAY:
+      return PIPE_CAP_MAX_TEXTURE_3D_LEVELS;
+   case PIPE_TEXTURE_CUBE:
+      return PIPE_CAP_MAX_TEXTURE_CUBE_LEVELS;
+   default:
+      assert(0);
+      return 0;
+   }
+}
 
 static enum pipe_texture_target
 gl_target_to_pipe(GLenum target)
@@ -333,6 +351,9 @@ guess_and_alloc_texture(struct st_context *st,
    GLuint bindings;
    GLuint ptWidth, ptHeight, ptDepth, ptLayers;
    enum pipe_format fmt;
+   enum pipe_texture_target pipe_target = gl_target_to_pipe(stObj->base.Target);
+   struct pipe_context *pipe = st->pipe;
+   struct pipe_screen *screen = pipe->screen;
 
    DBG("%s\n", __FUNCTION__);
 
@@ -374,7 +395,12 @@ guess_and_alloc_texture(struct st_context *st,
       GLuint l2width = util_logbase2(width);
       GLuint l2height = util_logbase2(height);
       GLuint l2depth = util_logbase2(depth);
+      int target_param = pipe_to_param(pipe_target);
+      int max_level = screen->get_param(screen, target_param);
       lastLevel = MAX2(MAX2(l2width, l2height), l2depth);
+
+      /* Clamp the last level against what the hw can do */
+      lastLevel = MIN2(lastLevel, max_level - 1);
    }
 
    /* Save the level=0 dimensions */
@@ -391,7 +417,7 @@ guess_and_alloc_texture(struct st_context *st,
                                    &ptWidth, &ptHeight, &ptDepth, &ptLayers);
 
    stObj->pt = st_texture_create(st,
-                                 gl_target_to_pipe(stObj->base.Target),
+                                 pipe_target,
                                  fmt,
                                  lastLevel,
                                  ptWidth,
-- 
1.7.5.3.367.ga9930