Submitted By: Jim Gifford <jim@linuxfromscratch.org>
Date: 07-14-2006
Initial Package Version: 0.97
Upstream Status: Unknown
Origin: Grub Bug Report - http://savannah.gnu.org/bugs/?func=detailitem&item_id=11312
Description: This patch fixes the following issues on x86_64
	1) malloc'd pages seem to lack the execute bit on x86_64;
	2) grub seems to use some stack pointer diversion to malloc'd pages;
	3) nested functions execute data on the stack;
	4) this causes a segfault (at least on my machine)

diff -Naur grub-0.97.orig/grub/asmstub.c grub-0.97/grub/asmstub.c
--- grub-0.97.orig/grub/asmstub.c	2005-02-16 12:45:14.000000000 -0800
+++ grub-0.97/grub/asmstub.c	2006-07-14 12:38:08.305902933 -0700
@@ -43,6 +43,8 @@
 #include <termios.h>
 #include <signal.h>
 
+#include <sys/mman.h>
+
 #ifdef __linux__
 # include <sys/ioctl.h>		/* ioctl */
 # if !defined(__GLIBC__) || \
@@ -142,14 +144,25 @@
     }
 
   assert (grub_scratch_mem == 0);
-  scratch = malloc (0x100000 + EXTENDED_MEMSIZE + 15);
+  scratch = mmap(NULL,
+                 0x100000 + EXTENDED_MEMSIZE + 15,
+                 PROT_EXEC | PROT_READ | PROT_WRITE,
+                 MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS | MAP_32BIT,
+                 -1,
+                 0);
+
   assert (scratch);
   grub_scratch_mem = (char *) ((((int) scratch) >> 4) << 4);
 
   /* FIXME: simulate the memory holes using mprot, if available. */
 
   assert (disks == 0);
-  disks = malloc (NUM_DISKS * sizeof (*disks));
+  disks = mmap(NULL,
+               NUM_DISKS * sizeof (*disks),
+               PROT_EXEC | PROT_READ | PROT_WRITE,
+               MAP_PRIVATE | MAP_GROWSDOWN | MAP_ANONYMOUS | MAP_32BIT,
+               -1,
+               0);
   assert (disks);
   /* Initialize DISKS.  */
   for (i = 0; i < NUM_DISKS; i++)
@@ -215,9 +228,9 @@
   /* Release memory. */
   restore_device_map (device_map);
   device_map = 0;
-  free (disks);
+  munmap(disks, NUM_DISKS * sizeof (*disks));
   disks = 0;
-  free (scratch);
+  munmap(scratch, 0x100000 + EXTENDED_MEMSIZE + 15);
   grub_scratch_mem = 0;
 
   if (serial_device)