Make PowerPC64 default to nonexecutable stack

5 files changed, 28 insertions, 11 deletions

diff --git a/elf/Makefile b/elf/Makefile
index b0420f50ef..bba6493084 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -899,8 +899,14 @@ $(objpfx)check-textrel: check-textrel.c
 	$(native-compile)
 
 check-execstack-CFLAGS = -O -Wall -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -std=gnu99
+# Perform the same operation as $(native-compile) but add the sysdeps
+# directories as header search locations.
 $(objpfx)check-execstack: check-execstack.c
-	$(native-compile)
+	$(make-target-directory)
+	$(patsubst %/,cd % &&,$(objpfx)) \
+	$(BUILD_CC) $($(basename $(<F))-CFLAGS) $(ALL_BUILD_CFLAGS) \
+	$(addprefix -I$(shell pwd)/,$(sysdirs)) -I$(shell pwd) \
+	$(firstword $(filter /%,$< $(shell pwd)/$<)) -o $(@F)
 
 check-localplt-CFLAGS = -O -Wall -D_GNU_SOURCE -std=gnu99
 $(objpfx)check-localplt: check-localplt.c
diff --git a/elf/check-execstack.c b/elf/check-execstack.c
index 55cf48721a..64353751e9 100644
--- a/elf/check-execstack.c
+++ b/elf/check-execstack.c
@@ -1,5 +1,5 @@
 /* Check for executable stacks in DSOs.
-   Copyright (C) 2009 Free Software Foundation, Inc.
+   Copyright (C) 2009, 2010 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contribute by Ulrich Drepper <drepper@redhat.com>. 2009.
 
@@ -26,6 +26,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <stackinfo.h>
 
 
 #ifdef BITS
@@ -150,9 +151,13 @@ main (int argc, char *argv[])
   int cnt;
   int result = 0;
 
-  for (cnt = 1; cnt < argc; ++cnt)
-    result |= handle_file (argv[cnt]);
-
+  /* We can return successfully, i.e., not fail, if PF_X isn't present.  If it
+   * is present then check for the GNU_STACK header.  */
+  if (DEFAULT_STACK_PERMS & PF_X)
+    {
+      for (cnt = 1; cnt < argc; ++cnt)
+	result |= handle_file (argv[cnt]);
+     }
   return result;
 }
 #endif
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 4c14f08e55..41b5ce7691 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -984,8 +984,10 @@ _dl_map_object_from_fd (const char *name, int fd, struct filebuf *fbp,
 	}
     }
 
-  /* Presumed absent PT_GNU_STACK.  */
-  uint_fast16_t stack_flags = PF_R|PF_W|PF_X;
+   /* On most platforms presume that PT_GNU_STACK is absent and the stack is
+    * executable.  Other platforms default to a nonexecutable stack and don't
+    * need PT_GNU_STACK to do so.  */
+   uint_fast16_t stack_flags = DEFAULT_STACK_PERMS;
 
   {
     /* Scan the program header table, collecting its load commands.  */
diff --git a/elf/dl-support.c b/elf/dl-support.c
index 5897b32e8c..1b128c37ff 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -32,6 +32,7 @@
 #include <dl-procinfo.h>
 #include <unsecvars.h>
 #include <hp-timing.h>
+#include <stackinfo.h>
 
 extern char *__progname;
 char **_dl_argv = &__progname;	/* This is checked for some error messages.  */
@@ -134,8 +135,9 @@ uint64_t _dl_hwcap __attribute__ ((nocommon));
    setting _dl_hwcap nonzero below, but we do anyway.  */
 uint64_t _dl_hwcap_mask __attribute__ ((nocommon));
 
-/* Prevailing state of the stack, PF_X indicating it's executable.  */
-ElfW(Word) _dl_stack_flags = PF_R|PF_W|PF_X;
+/* Prevailing state of the stack.  Generally this includes PF_X, indicating it's
+ * executable but this isn't true for all platforms.  */
+ElfW(Word) _dl_stack_flags = DEFAULT_STACK_PERMS;
 
 /* If loading a shared object requires that we make the stack executable
    when it was not, we do it by calling this function.
diff --git a/elf/rtld.c b/elf/rtld.c
index d53730fe30..851038089c 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -40,6 +40,7 @@
 #include <dl-osinfo.h>
 #include <dl-procinfo.h>
 #include <tls.h>
+#include <stackinfo.h>
 
 #include <assert.h>
 
@@ -122,8 +123,9 @@ INTVARDEF(_dl_starting_up)
    (except those which cannot be added for some reason).  */
 struct rtld_global _rtld_global =
   {
-    /* Default presumption without further information is executable stack.  */
-    ._dl_stack_flags = PF_R|PF_W|PF_X,
+    /* Generally the default presumption without further information is an
+     * executable stack but this is not true for all platforms.  */
+    ._dl_stack_flags = DEFAULT_STACK_PERMS,
 #ifdef _LIBC_REENTRANT
     ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
     ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,