* crtstuff.c (HIDDEN_DTOR_LIST_END): New macro.

	(__do_global_dtors_aux): Use more paranoid loop to run
	destructors if HIDDEN_DTOR_LIST_END.
	(__DTOR_END__): Export as a hidden symbol when HIDDEN_DTOR_LIST_END.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@124444 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 41 insertions, 9 deletions

diff --git a/gcc/crtstuff.c b/gcc/crtstuff.c
index e847ad04760..fc57d45afc8 100644
--- a/gcc/crtstuff.c
+++ b/gcc/crtstuff.c
@@ -106,6 +106,11 @@ call_ ## FUNC (void)					\
 # define EH_FRAME_SECTION_CONST
 #endif
 
+#if !defined(DTOR_LIST_END) && defined(OBJECT_FORMAT_ELF) \
+    && defined(HAVE_GAS_HIDDEN) && !defined(FINI_ARRAY_SECTION_ASM_OP)
+# define HIDDEN_DTOR_LIST_END
+#endif
+
 /* We do not want to add the weak attribute to the declarations of these
    routines in unwind-dw2-fde.h because that will cause the definition of
    these symbols to be weak as well.
@@ -265,10 +270,6 @@ extern void __cxa_finalize (void *) TARGET_ATTRIBUTE_WEAK;
 static void __attribute__((used))
 __do_global_dtors_aux (void)
 {
-#ifndef FINI_ARRAY_SECTION_ASM_OP
-  static func_ptr *p = __DTOR_LIST__ + 1;
-  func_ptr f;
-#endif /* !defined(FINI_ARRAY_SECTION_ASM_OP)  */
   static _Bool completed;
 
   if (__builtin_expect (completed, 0))
@@ -282,12 +283,32 @@ __do_global_dtors_aux (void)
 #ifdef FINI_ARRAY_SECTION_ASM_OP
   /* If we are using .fini_array then destructors will be run via that
      mechanism.  */
+#elif defined(HIDDEN_DTOR_LIST_END)
+  {
+    /* Safer version that makes sure only .dtors function pointers are
+       called even if the static variable is maliciously changed.  */
+    extern func_ptr __DTOR_END__[] __attribute__((visibility ("hidden")));
+    static size_t dtor_idx;
+    const size_t max_idx = __DTOR_END__ - __DTOR_LIST__ - 1;
+    func_ptr f;
+
+    while (dtor_idx < max_idx)
+      {
+	f = __DTOR_LIST__[++dtor_idx];
+	f ();
+      }
+  }
 #else /* !defined (FINI_ARRAY_SECTION_ASM_OP) */
-  while ((f = *p))
-    {
-      p++;
-      f ();
-    }
+  {
+    static func_ptr *p = __DTOR_LIST__ + 1;
+    func_ptr f;
+
+    while ((f = *p))
+      {
+	p++;
+	f ();
+      }
+  }
 #endif /* !defined(FINI_ARRAY_SECTION_ASM_OP) */
 
 #ifdef USE_EH_FRAME_REGISTRY
@@ -471,6 +492,17 @@ STATIC func_ptr __CTOR_END__[1]
 
 #ifdef DTOR_LIST_END
 DTOR_LIST_END;
+#elif defined(HIDDEN_DTOR_LIST_END)
+#ifdef DTORS_SECTION_ASM_OP
+asm (DTORS_SECTION_ASM_OP);
+#endif
+func_ptr __DTOR_END__[1]
+  __attribute__ ((unused,
+#ifndef DTORS_SECTION_ASM_OP
+		  section(".dtors"),
+#endif
+		  aligned(sizeof(func_ptr)), visibility ("hidden")))
+  = { (func_ptr) 0 };
 #elif defined(DTORS_SECTION_ASM_OP)
 asm (DTORS_SECTION_ASM_OP);
 STATIC func_ptr __DTOR_END__[1]