Submitted By: Robert Connolly <robert at linuxfromscratch dot org> (ashes)
Date: 2011-08-13
Initial Package Version: 2.12.2
Upstream Status: Not submitted - PaX specific. Will not be accepted upstream.
Origin:
http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo/src/patchsets/glibc/2.12.2/3000_all_2.3.6-dl_execstack-PaX-support.patch?view=markup
Description:

	With latest versions of glibc, a lot of apps failed on a PaX enabled
	system with:
		cannot enable executable stack as shared object requires: Permission denied

	This is due to PaX 'exec-protecting' the stack, and ld.so then trying
	to make the stack executable due to some libraries not containing the
	PT_GNU_STACK section.  Bug #32960.  <azarah@gentoo.org> (12 Nov 2003).

	Patch also NPTL. Bug #116086. <kevquinn@gentoo.org> (20 Dec 2005).

diff -Naur glibc-2.12.2.orig/nptl/allocatestack.c glibc-2.12.2/nptl/allocatestack.c
--- glibc-2.12.2.orig/nptl/allocatestack.c	2010-12-13 10:47:26.000000000 +0000
+++ glibc-2.12.2/nptl/allocatestack.c	2011-08-14 03:30:30.368648803 +0000
@@ -329,7 +329,8 @@
 # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
 #endif
   if (mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
-    return errno;
+    if (errno != EACCES) /* PAX is enabled */
+    	return errno;
 
   return 0;
 }
diff -Naur glibc-2.12.2.orig/sysdeps/unix/sysv/linux/dl-execstack.c glibc-2.12.2/sysdeps/unix/sysv/linux/dl-execstack.c
--- glibc-2.12.2.orig/sysdeps/unix/sysv/linux/dl-execstack.c	2010-12-13 10:47:26.000000000 +0000
+++ glibc-2.12.2/sysdeps/unix/sysv/linux/dl-execstack.c	2011-08-14 03:30:30.367648794 +0000
@@ -63,7 +63,10 @@
       else
 # endif
 	{
-	  result = errno;
+	  if (errno == EACCES)  /* PAX is enabled */
+	    result = 0;
+	  else
+	    result = errno;
 	  goto out;
 	}
     }
@@ -89,7 +92,12 @@
 	page -= size;
       else
 	{
-	  if (errno != ENOMEM)	/* Unexpected failure mode.  */
+	  if (errno == EACCES)		/* PAX is enabled */
+	    {
+	      result = 0;
+	      goto out;
+	    }
+	  else if (errno != ENOMEM)	/* Unexpected failure mode.  */
 	    {
 	      result = errno;
 	      goto out;
@@ -115,7 +123,12 @@
 	page += size;
       else
 	{
-	  if (errno != ENOMEM)	/* Unexpected failure mode.  */
+	  if (errno == EACCES)		/* PAX is enabled */
+	    {
+	      result = 0;
+	      goto out;
+	    }
+	  else if (errno != ENOMEM)	/* Unexpected failure mode.  */
 	    {
 	      result = errno;
 	      goto out;