diff mbox

New configure option to default enable Smart Stack Protection

Message ID 39898046.VMObuEqk0e@laptop1.gw.ume.nu
State New
Headers show

Commit Message

Magnus Granberg July 2, 2015, 11:01 p.m. UTC 
Hi
Working on a patch that enable Smart Stack Protection as default.
I still miss docs and testcase for the patch. I need you ides and help.

/Magnus G.
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diff mbox

Patch

--- a/gcc/configure.ac	2014-12-05 00:53:24.000000000 +0100
+++ b/gcc/configure.ac	2015-06-08 23:27:11.744348211 +0200
@@ -5221,6 +5119,25 @@  if test x$gcc_cv_libc_provides_ssp = xye
 	    [Define if your target C library provides stack protector support])
 fi
 
+# Check whether --enable-default-ssp was given.
+AC_ARG_ENABLE(default-ssp,
+[AS_HELP_STRING([--enable-default-ssp],
+  [enable Smart Stack Protection as default])],
+if test x$gcc_cv_libc_provides_ssp = xyes; then
+  case "$target" in
+    ia64*-*-*) enable_default_ssp=no ;;
+    *) enable_default_ssp=$enableval ;;
+  esac
+else
+  enable_default_ssp=no
+fi,
+enable_default_ssp=no)
+if test x$enable_default_ssp == xyes ; then
+  AC_DEFINE(ENABLE_DEFAULT_SSP, 1,
+      [Define if your target supports default STACK-PROTECTOR and it is enabled.])
+fi
+AC_SUBST([enable_default_ssp])
+
 # Test for <sys/sdt.h> on the target.
 GCC_TARGET_TEMPLATE([HAVE_SYS_SDT_H])
 AC_MSG_CHECKING(sys/sdt.h in the target C library)
--- a/gcc/defaults.h	2014-11-01 09:13:09.000000000 +0100
+++ b/gcc/defaults.h	2015-06-08 22:43:18.764269749 +0200
@@ -1263,6 +1263,18 @@  see the files COPYING3 and COPYING.RUNTI
 #define STACK_SIZE_MODE word_mode
 #endif
 
+/* Default value for flag_stack_protect when flag_stack_protect is initialized to -1:
+   --enable-default-ssp: Default flag_stack_protect to -fstack-protector-strong.
+   --disable-default-ssp: Default flag_stack_protect to 0.
+ */
+#ifdef ENABLE_DEFAULT_SSP
+# ifndef DEFAULT_FLAG_SSP
+#  define DEFAULT_FLAG_SSP 3
+# endif
+#else
+# define DEFAULT_FLAG_SSP 0
+#endif
+
 /* Provide default values for the macros controlling stack checking.  */
 
 /* The default is neither full builtin stack checking...  */
--- a/gcc/common.opt	2014-10-28 11:33:04.000000000 +0100
+++ b/gcc/common.opt	2015-06-08 22:41:30.114266512 +0200
@@ -2054,15 +2054,15 @@  Common RejectNegative Joined Var(common_
 -fstack-limit-symbol=<name>	Trap if the stack goes past symbol <name>
 
 fstack-protector
-Common Report Var(flag_stack_protect, 1)
+Common Report Var(flag_stack_protect, 1) Init(-1)
 Use propolice as a stack protection method
 
 fstack-protector-all
-Common Report RejectNegative Var(flag_stack_protect, 2)
+Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1)
 Use a stack protection method for every function
 
 fstack-protector-strong
-Common Report RejectNegative Var(flag_stack_protect, 3)
+Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1)
 Use a smart stack protection method for certain functions
 
 fstack-protector-explicit
-Common Report RejectNegative Var(flag_stack_protect, 4)
+Common Report RejectNegative Var(flag_stack_protect, 4) Init(-1)
 Use stack protection method only for functions with the stack_protect attribute
 
 fstack-usage
--- a/gcc/opts.c	2014-10-28 11:33:04.000000000 +0100
+++ b/gcc/opts.c	2015-06-27 01:06:48.670870534 +0200
@@ -739,6 +740,1 @@  finish_options (struct gcc_options *opts
	   opts->x_flag_opts_finished = true;
	 }
 
+  /* We initialize opts->x_flag_stack_protect to -1 so that targets
+      can set a default value.  */
+  if (opts->x_flag_stack_protect == -1)
+    opts->x_flag_stack_protect = DEFAULT_FLAG_SSP;
+
   if (opts->x_optimize == 0)
     {
       /* Inlining does not work if not optimizing,