#

# As of 2013-08-09 this patch is posted upstream here, but not checked in yet:

# http://sourceware.org/ml/libc-alpha/2013-07/msg00367.html

# http://sourceware.org/ml/libc-alpha/2013-08/msg00057.html

#

# Red Hat bug:

# https://bugzilla.redhat.com/show_bug.cgi?id=990481

#

# Upstream bug:

# http://sourceware.org/bugzilla/show_bug.cgi?id=15754

#

# 2013-07-19  Carlos O'Donell  <carlos@redhat.com>

#

# 	[BZ #15754]

# 	* elf/Makefile (tests): Add tst-ptrguard1.

# 	(tests-static): Add tst-ptrguard1-static.

# 	(tst-ptrguard1-ARGS): Define.

# 	(tst-ptrguard1-static-ARGS): Define.

# 	* elf/tst-ptrguard1.c: New file.

# 	* elf/tst-ptrguard1-static.c: New file.

# 	* sysdeps/x86_64/stackguard-macros.h: Define POINTER_CHK_GUARD.

# 	* sysdeps/i386/stackguard-macros.h: Likewise.

# 	* sysdeps/powerpc/powerpc32/stackguard-macros.h: Likewise.

#	* sysdeps/powerpc/powerpc64/stackguard-macros.h: Likewise.

#	* sysdeps/s390/s390-32/stackguard-macros.h: Likewise.

#	* sysdeps/s390/s390-64/stackguard-macros.h: Likewise.

#

# 2013-07-19  Hector Marco  <hecmargi@upv.es>

# 	    Ismael Ripoll  <iripoll@disca.upv.es>

# 	    Carlos O'Donell  <carlos@redhat.com>

#

# 	[BZ #15754]

# 	* sysdeps/generic/stackguard-macros.h: Define __pointer_chk_guard_local

# 	and POINTER_CHK_GUARD.

# 	* csu/libc-start.c [!SHARED && !THREAD_SET_POINTER_GUARD]:

# 	Define __pointer_chk_guard_local.

# 	(LIBC_START_MAIN) [!SHARED]: Call _dl_setup_pointer_guard.

# 	Use THREAD_SET_POINTER_GUARD or set __pointer_chk_guard_local.

#

diff -urN glibc-2.17-c758a686/csu/libc-start.c glibc-2.17-c758a686/csu/libc-start.c

--- glibc-2.17-c758a686/csu/libc-start.c	2013-08-09 17:40:41.662856773 -0400

+++ glibc-2.17-c758a686/csu/libc-start.c	2013-08-09 17:53:40.383236966 -0400

@@ -38,6 +38,12 @@

    in thread local area.  */

 uintptr_t __stack_chk_guard attribute_relro;

 # endif

+# ifndef  THREAD_SET_POINTER_GUARD

+/* Only exported for architectures that don't store the pointer guard

+   value in thread local area.  */

+uintptr_t __pointer_chk_guard_local

+	attribute_relro attribute_hidden __attribute__ ((nocommon));

+# endif

 #endif

 #ifdef HAVE_PTR_NTHREADS

@@ -184,6 +190,16 @@

 # else

   __stack_chk_guard = stack_chk_guard;

 # endif

+

+  /* Set up the pointer guard value.  */

+  uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random,

+							 stack_chk_guard);

+# ifdef THREAD_SET_POINTER_GUARD

+  THREAD_SET_POINTER_GUARD (pointer_chk_guard);

+# else

+  __pointer_chk_guard_local = pointer_chk_guard;

+# endif

+

 #endif

   /* Register the destructor of the dynamic linker if there is any.  */

diff -urN glibc-2.17-c758a686/elf/Makefile glibc-2.17-c758a686/elf/Makefile

--- glibc-2.17-c758a686/elf/Makefile	2013-08-09 17:40:41.757856472 -0400

+++ glibc-2.17-c758a686/elf/Makefile	2013-08-09 17:53:40.383236966 -0400

@@ -121,7 +121,8 @@

 tests = tst-tls1 tst-tls2 tst-tls9 tst-leaks1 \

 	tst-array1 tst-array2 tst-array3 tst-array4 tst-array5

 tests-static = tst-tls1-static tst-tls2-static tst-stackguard1-static \

-	       tst-leaks1-static tst-array1-static tst-array5-static

+	       tst-leaks1-static tst-array1-static tst-array5-static \

+	       tst-ptrguard1-static

 ifeq (yes,$(build-shared))

 tests-static += tst-tls9-static

 tst-tls9-static-ENV = \

@@ -145,7 +146,7 @@

 	 tst-audit1 tst-audit2 tst-audit8 tst-audit9 \

 	 tst-stackguard1 tst-addr1 tst-thrlock \

 	 tst-unique1 tst-unique2 tst-unique3 tst-unique4 \

-	 tst-initorder tst-initorder2 tst-relsort1

+	 tst-initorder tst-initorder2 tst-relsort1 tst-ptrguard1

 #	 reldep9

 test-srcs = tst-pathopt

 selinux-enabled := $(shell cat /selinux/enforce 2> /dev/null)

@@ -1062,6 +1063,9 @@

 tst-stackguard1-ARGS = --command "$(host-built-program-cmd) --child"

 tst-stackguard1-static-ARGS = --command "$(objpfx)tst-stackguard1-static --child"

+tst-ptrguard1-ARGS = --command "$(host-built-program-cmd) --child"

+tst-ptrguard1-static-ARGS = --command "$(objpfx)tst-ptrguard1-static --child"

+

 $(objpfx)tst-leaks1: $(libdl)

 $(objpfx)tst-leaks1-mem: $(objpfx)tst-leaks1.out

 	$(common-objpfx)malloc/mtrace $(objpfx)tst-leaks1.mtrace > $@

diff -urN glibc-2.17-c758a686/elf/tst-ptrguard1.c glibc-2.17-c758a686/elf/tst-ptrguard1.c

--- glibc-2.17-c758a686/elf/tst-ptrguard1.c	1969-12-31 19:00:00.000000000 -0500

+++ glibc-2.17-c758a686/elf/tst-ptrguard1.c	2013-08-09 17:53:40.383236966 -0400

@@ -0,0 +1,202 @@

+/* Copyright (C) 2013 Free Software Foundation, Inc.

+   This file is part of the GNU C Library.

+

+   The GNU C Library is free software; you can redistribute it and/or

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <http://www.gnu.org/licenses/>.  */

+

+#include <errno.h>

+#include <stdbool.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>

+#include <sys/wait.h>

+#include <stackguard-macros.h>

+#include <tls.h>

+#include <unistd.h>

+

+#ifndef POINTER_CHK_GUARD

+extern uintptr_t __pointer_chk_guard_local;

+# define POINTER_CHK_GUARD __pointer_chk_guard_local

+#endif

+

+static const char *command;

+static bool child;

+static uintptr_t ptr_chk_guard_copy;

+static bool ptr_chk_guard_copy_set;

+static int fds[2];

+

+static void __attribute__ ((constructor))

+con (void)

+{

+  ptr_chk_guard_copy = POINTER_CHK_GUARD;

+  ptr_chk_guard_copy_set = true;

+}

+

+static int

+uintptr_t_cmp (const void *a, const void *b)

+{

+  if (*(uintptr_t *) a < *(uintptr_t *) b)

+    return 1;

+  if (*(uintptr_t *) a > *(uintptr_t *) b)

+    return -1;

+  return 0;

+}

+

+static int

+do_test (void)

+{

+  if (!ptr_chk_guard_copy_set)

+    {

+      puts ("constructor has not been run");

+      return 1;

+    }

+

+  if (ptr_chk_guard_copy != POINTER_CHK_GUARD)

+    {

+      puts ("POINTER_CHK_GUARD changed between constructor and do_test");

+      return 1;

+    }

+

+  if (child)

+    {

+      write (2, &ptr_chk_guard_copy, sizeof (ptr_chk_guard_copy));

+      return 0;

+    }

+

+  if (command == NULL)

+    {

+      puts ("missing --command or --child argument");

+      return 1;

+    }

+

+#define N 16

+  uintptr_t child_ptr_chk_guards[N + 1];

+  child_ptr_chk_guards[N] = ptr_chk_guard_copy;

+  int i;

+  for (i = 0; i < N; ++i)

+    {

+      if (pipe (fds) < 0)

+	{

+	  printf ("couldn't create pipe: %m\n");

+	  return 1;

+	}

+

+      pid_t pid = fork ();

+      if (pid < 0)

+	{

+	  printf ("fork failed: %m\n");

+	  return 1;

+	}

+

+      if (!pid)

+	{

+	  if (ptr_chk_guard_copy != POINTER_CHK_GUARD)

+	    {

+	      puts ("POINTER_CHK_GUARD changed after fork");

+	      exit (1);

+	    }

+

+	  close (fds[0]);

+	  close (2);

+	  dup2 (fds[1], 2);

+	  close (fds[1]);

+

+	  system (command);

+	  exit (0);

+	}

+

+      close (fds[1]);

+

+      if (TEMP_FAILURE_RETRY (read (fds[0], &child_ptr_chk_guards[i],

+				    sizeof (uintptr_t))) != sizeof (uintptr_t))

+	{

+	  puts ("could not read ptr_chk_guard value from child");

+	  return 1;

+	}

+

+      close (fds[0]);

+

+      pid_t termpid;

+      int status;

+      termpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0));

+      if (termpid == -1)

+	{

+	  printf ("waitpid failed: %m\n");

+	  return 1;

+	}

+      else if (termpid != pid)

+	{

+	  printf ("waitpid returned %ld != %ld\n",

+		  (long int) termpid, (long int) pid);

+	  return 1;

+	}

+      else if (!WIFEXITED (status) || WEXITSTATUS (status))

+	{

+	  puts ("child hasn't exited with exit status 0");

+	  return 1;

+	}

+    }

+

+  qsort (child_ptr_chk_guards, N + 1, sizeof (uintptr_t), uintptr_t_cmp);

+

+  /* The default pointer guard is the same as the default stack guard.

+     They are only set to default if dl_random is NULL.  */

+  uintptr_t default_guard = 0;

+  unsigned char *p = (unsigned char *) &default_guard;

+  p[sizeof (uintptr_t) - 1] = 255;

+  p[sizeof (uintptr_t) - 2] = '\n';

+  p[0] = 0;

+

+  /* Test if the pointer guard canaries are either randomized,

+     or equal to the default pointer guard canary value.

+     Even with randomized pointer guards it might happen

+     that the random number generator generates the same

+     values, but if that happens in more than half from

+     the 16 runs, something is very wrong.  */

+  int ndifferences = 0;

+  int ndefaults = 0;

+  for (i = 0; i < N; ++i)

+    {

+      if (child_ptr_chk_guards[i] != child_ptr_chk_guards[i+1])

+	ndifferences++;

+      else if (child_ptr_chk_guards[i] == default_guard)

+	ndefaults++;

+    }

+

+  printf ("differences %d defaults %d\n", ndifferences, ndefaults);

+

+  if (ndifferences < N / 2 && ndefaults < N / 2)

+    {

+      puts ("pointer guard canaries are not randomized enough");

+      puts ("nor equal to the default canary value");

+      return 1;

+    }

+

+  return 0;

+}

+

+#define OPT_COMMAND	10000

+#define OPT_CHILD	10001

+#define CMDLINE_OPTIONS	\

+  { "command", required_argument, NULL, OPT_COMMAND },  \

+  { "child", no_argument, NULL, OPT_CHILD },

+#define CMDLINE_PROCESS	\

+  case OPT_COMMAND:	\

+    command = optarg;	\

+    break;		\

+  case OPT_CHILD:	\

+    child = true;	\

+    break;

+#define TEST_FUNCTION do_test ()

+#include "../test-skeleton.c"

diff -urN glibc-2.17-c758a686/elf/tst-ptrguard1-static.c glibc-2.17-c758a686/elf/tst-ptrguard1-static.c

--- glibc-2.17-c758a686/elf/tst-ptrguard1-static.c	1969-12-31 19:00:00.000000000 -0500

+++ glibc-2.17-c758a686/elf/tst-ptrguard1-static.c	2013-08-09 17:53:40.384236962 -0400

@@ -0,0 +1 @@

+#include "tst-ptrguard1.c"

diff -urN glibc-2.17-c758a686/sysdeps/generic/stackguard-macros.h glibc-2.17-c758a686/sysdeps/generic/stackguard-macros.h

--- glibc-2.17-c758a686/sysdeps/generic/stackguard-macros.h	2013-08-09 17:40:41.917855965 -0400

+++ glibc-2.17-c758a686/sysdeps/generic/stackguard-macros.h	2013-08-09 17:53:40.384236962 -0400

@@ -2,3 +2,6 @@

 extern uintptr_t __stack_chk_guard;

 #define STACK_CHK_GUARD __stack_chk_guard

+

+extern uintptr_t __pointer_chk_guard_local;

+#define POINTER_CHK_GUARD __pointer_chk_guard_local

diff -urN glibc-2.17-c758a686/sysdeps/i386/stackguard-macros.h glibc-2.17-c758a686/sysdeps/i386/stackguard-macros.h

--- glibc-2.17-c758a686/sysdeps/i386/stackguard-macros.h	2013-08-09 17:40:41.893856041 -0400

+++ glibc-2.17-c758a686/sysdeps/i386/stackguard-macros.h	2013-08-09 22:44:04.774298862 -0400

@@ -2,3 +2,11 @@

 #define STACK_CHK_GUARD \

   ({ uintptr_t x; asm ("movl %%gs:0x14, %0" : "=r" (x)); x; })

+

+#define POINTER_CHK_GUARD \

+  ({								\

+     uintptr_t x; 						\

+     asm ("movl %%gs:%c1, %0" : "=r" (x)			\

+	  : "i" (offsetof (tcbhead_t, pointer_guard)));		\

+     x;								\

+   })

diff -urN glibc-2.17-c758a686/sysdeps/powerpc/powerpc32/stackguard-macros.h glibc-2.17-c758a686/sysdeps/powerpc/powerpc32/stackguard-macros.h

--- glibc-2.17-c758a686/sysdeps/powerpc/powerpc32/stackguard-macros.h	2013-08-09 17:40:42.006855683 -0400

+++ glibc-2.17-c758a686/sysdeps/powerpc/powerpc32/stackguard-macros.h	2013-08-09 22:24:48.778793075 -0400

@@ -2,3 +2,13 @@

 #define STACK_CHK_GUARD \

   ({ uintptr_t x; asm ("lwz %0,-28680(2)" : "=r" (x)); x; })

+

+#define POINTER_CHK_GUARD \

+  ({												\

+     uintptr_t x;										\

+     asm ("lwz %0,%1(2)"									\

+	  : "=r" (x)										\

+	  : "i" (offsetof (tcbhead_t, pointer_guard) - TLS_TCB_OFFSET - sizeof (tcbhead_t))	\

+         );											\

+     x;												\

+   })

diff -urN glibc-2.17-c758a686/sysdeps/powerpc/powerpc64/stackguard-macros.h glibc-2.17-c758a686/sysdeps/powerpc/powerpc64/stackguard-macros.h

--- glibc-2.17-c758a686/sysdeps/powerpc/powerpc64/stackguard-macros.h	2013-08-09 17:40:41.994855721 -0400

+++ glibc-2.17-c758a686/sysdeps/powerpc/powerpc64/stackguard-macros.h	2013-08-09 22:24:47.831795865 -0400

@@ -2,3 +2,13 @@

 #define STACK_CHK_GUARD \

   ({ uintptr_t x; asm ("ld %0,-28688(13)" : "=r" (x)); x; })

+

+#define POINTER_CHK_GUARD \

+  ({												\

+     uintptr_t x;										\

+     asm ("ld %0,%1(13)"									\

+	  : "=r" (x)										\

+	  : "i" (offsetof (tcbhead_t, pointer_guard) - TLS_TCB_OFFSET - sizeof (tcbhead_t))	\

+         );											\

+     x;												\

+   })

diff -urN glibc-2.17-c758a686/sysdeps/s390/s390-32/stackguard-macros.h glibc-2.17-c758a686/sysdeps/s390/s390-32/stackguard-macros.h

--- glibc-2.17-c758a686/sysdeps/s390/s390-32/stackguard-macros.h	2013-08-09 17:40:42.059855515 -0400

+++ glibc-2.17-c758a686/sysdeps/s390/s390-32/stackguard-macros.h	2013-08-09 22:39:31.913120373 -0400

@@ -2,3 +2,15 @@

 #define STACK_CHK_GUARD \

   ({ uintptr_t x; asm ("ear %0,%%a0; l %0,0x14(%0)" : "=a" (x)); x; })

+

+/* On s390/s390x there is no unique pointer guard, instead we use the

+   same value as the stack guard.  */

+#define POINTER_CHK_GUARD \

+  ({							\

+     uintptr_t x;					\

+     asm ("ear %0,%%a0; l %0,%1(%0)"			\

+	  : "=a" (x)					\

+	  : "i" (offsetof (tcbhead_t, stack_guard)));	\

+     x;							\

+   })

+

diff -urN glibc-2.17-c758a686/sysdeps/x86_64/stackguard-macros.h glibc-2.17-c758a686/sysdeps/x86_64/stackguard-macros.h

--- glibc-2.17-c758a686/sysdeps/x86_64/stackguard-macros.h	2013-08-09 17:40:42.013855661 -0400

+++ glibc-2.17-c758a686/sysdeps/x86_64/stackguard-macros.h	2013-08-09 22:44:53.550153736 -0400

@@ -4,3 +4,11 @@

   ({ uintptr_t x;						\

      asm ("mov %%fs:%c1, %0" : "=r" (x)				\

 	  : "i" (offsetof (tcbhead_t, stack_guard))); x; })

+

+#define POINTER_CHK_GUARD \

+  ({								\

+     uintptr_t x;						\

+     asm ("mov %%fs:%c1, %0" : "=r" (x)				\

+	  : "i" (offsetof (tcbhead_t, pointer_guard)));		\

+     x;								\

+   })

--- glibc-2.17-c758a686/sysdeps/s390/s390-64/stackguard-macros.h	2013-08-09 17:40:42.057855522 -0400

+++ glibc-2.17-c758a686/sysdeps/s390/s390-64/stackguard-macros.h	2013-08-26 15:21:27.239043425 -0400

@@ -2,3 +2,17 @@

 #define STACK_CHK_GUARD \

   ({ uintptr_t x; asm ("ear %0,%%a0; sllg %0,%0,32; ear %0,%%a1; lg %0,0x28(%0)" : "=a" (x)); x; })

+

+/* On s390/s390x there is no unique pointer guard, instead we use the

+   same value as the stack guard.  */

+#define POINTER_CHK_GUARD \

+  ({							\

+     uintptr_t x;					\

+     asm ("ear %0,%%a0;"				\

+	  "sllg %0,%0,32;"				\

+	  "ear %0,%%a1;"				\

+	  "lg %0,%1(%0)"				\

+	  : "=a" (x)					\

+	  : "i" (offsetof (tcbhead_t, stack_guard)));	\

+     x;							\

+   })