Mesa (master): glsl: fix several use-after-free bugs
Brian Paul
brianp at kemper.freedesktop.org
Mon Oct 20 15:39:38 UTC 2014
Module: Mesa
Branch: master
Commit: 14379a0644ed69c5b7a6c6150ae91eba6f316e33
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=14379a0644ed69c5b7a6c6150ae91eba6f316e33
Author: Brian Paul <brianp at vmware.com>
Date: Fri Oct 17 13:31:53 2014 -0600
glsl: fix several use-after-free bugs
The get_variable_being_redeclared() function can free the 'var' argument.
Thereafter, we cannot assume that 'var' is a valid pointer. This patch
replaces 'var->name' with 'earlier->name' in two places and calls
is_gl_identifier(var->name) before 'var' might get freed.
This fixes several piglit GLSL crashes, including:
spec/glsl-1.50/execution/geometry/clip-distance-in-param
spec/glsl-1.50/execution/geometry/clip-distance-bulk-copy
spec/glsl-1.50/compiler/gs-redeclares-pervertex-out-before-global-redeclaration.geom
I'm not sure why these were not spotted sooner.
A similar bug was previously fixed by f9cecca7a.
Cc: <mesa-stable at lists.freedesktop.org>
Reviewed-by: Chris Forbes <chrisf at ijw.co.nz>
---
src/glsl/ast_to_hir.cpp | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index afbb3b2..fe1e129 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -3767,7 +3767,7 @@ ast_declarator_list::hir(exec_list *instructions,
earlier->data.how_declared == ir_var_declared_in_block) {
_mesa_glsl_error(&loc, state,
"`%s' has already been redeclared using "
- "gl_PerVertex", var->name);
+ "gl_PerVertex", earlier->name);
}
earlier->data.how_declared = ir_var_declared_normally;
}
@@ -5706,17 +5706,21 @@ ast_interface_block::hir(exec_list *instructions,
var->data.stream = this->layout.stream;
+ /* Examine var name here since var may get deleted in the next call */
+ bool var_is_gl_id = is_gl_identifier(var->name);
+
if (redeclaring_per_vertex) {
ir_variable *earlier =
get_variable_being_redeclared(var, loc, state,
true /* allow_all_redeclarations */);
- if (!is_gl_identifier(var->name) || earlier == NULL) {
+ if (!var_is_gl_id || earlier == NULL) {
_mesa_glsl_error(&loc, state,
"redeclaration of gl_PerVertex can only "
"include built-in variables");
} else if (earlier->data.how_declared == ir_var_declared_normally) {
_mesa_glsl_error(&loc, state,
- "`%s' has already been redeclared", var->name);
+ "`%s' has already been redeclared",
+ earlier->name);
} else {
earlier->data.how_declared = ir_var_declared_in_block;
earlier->reinit_interface_type(block_type);
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