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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@lists.freedesktop.org>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
This commit is contained in:
Brian Paul 2014-10-17 13:31:53 -06:00
parent 953a0af8e3
commit 14379a0644
1 changed files with 7 additions and 3 deletions
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10
src/glsl/ast_to_hir.cpp
View File

@ -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);