grub2/SOURCES/0552-nx-set-attrs-in-our-kernel-loaders.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Tue, 22 Mar 2022 10:57:07 -0400
Subject: [PATCH] nx: set attrs in our kernel loaders

For NX, our kernel loaders need to set write and execute page
permissions on allocated pages and the stack.

This patch adds those calls.

Signed-off-by: Peter Jones <pjones@redhat.com>
[rharwood: fix aarch64 callsites]
(cherry-picked from commit a9f79a997f01a83b36cdfa89ef2e72ac2a17c06c)
[rharwood: double verification]
(cherry picked from commit daba852bd3e4d7b7784b19cf7acf107dc3c0dce4)
[rharwood: stack_attrs initialization, no risc-v, arm renames, arm age]
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
 grub-core/kern/efi/mm.c            |  78 ++++++++++++++++++
 grub-core/loader/arm64/linux.c     |  16 +++-
 grub-core/loader/arm64/xen_boot.c  |   4 +-
 grub-core/loader/efi/chainloader.c |  11 +++
 grub-core/loader/efi/linux.c       | 162 ++++++++++++++++++++++++++++++++++++-
 grub-core/loader/i386/efi/linux.c  |  26 +++++-
 grub-core/loader/i386/linux.c      |   5 ++
 include/grub/efi/efi.h             |   6 +-
 include/grub/efi/linux.h           |  17 +++-
 include/grub/efi/pe32.h            |   2 +
 10 files changed, 312 insertions(+), 15 deletions(-)

diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index 2cf4a4883a..8a896144df 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -602,6 +602,82 @@ print_memory_map (grub_efi_memory_descriptor_t *memory_map,
 }
 #endif
 
+grub_addr_t grub_stack_addr = (grub_addr_t)-1ll;
+grub_size_t grub_stack_size = 0;
+
+static void
+grub_nx_init (void)
+{
+  grub_uint64_t attrs, stack_attrs;
+  grub_err_t err;
+  grub_addr_t stack_current, stack_end;
+  const grub_uint64_t page_size = 4096;
+  const grub_uint64_t page_mask = ~(page_size - 1);
+
+  /*
+   * These are to confirm that the flags are working as expected when
+   * debugging.
+   */
+  attrs = 0;
+  stack_current = (grub_addr_t)grub_nx_init & page_mask;
+  err = grub_get_mem_attrs (stack_current, page_size, &attrs);
+  if (err)
+    {
+      grub_dprintf ("nx",
+		    "grub_get_mem_attrs(0x%"PRIxGRUB_UINT64_T", ...) -> 0x%x\n",
+		    stack_current, err);
+      grub_error_pop ();
+    }
+  else
+    grub_dprintf ("nx", "page attrs for grub_nx_init (%p) are %c%c%c\n",
+		  grub_dl_load_core,
+		  (attrs & GRUB_MEM_ATTR_R) ? 'r' : '-',
+		  (attrs & GRUB_MEM_ATTR_R) ? 'w' : '-',
+		  (attrs & GRUB_MEM_ATTR_R) ? 'x' : '-');
+
+  stack_current = (grub_addr_t)&stack_current & page_mask;
+  err = grub_get_mem_attrs (stack_current, page_size, &stack_attrs);
+  if (err)
+    {
+      grub_dprintf ("nx",
+		    "grub_get_mem_attrs(0x%"PRIxGRUB_UINT64_T", ...) -> 0x%x\n",
+		    stack_current, err);
+      grub_error_pop ();
+    }
+  else
+    {
+      attrs = stack_attrs;
+      grub_dprintf ("nx", "page attrs for stack (%p) are %c%c%c\n",
+                    &attrs,
+                    (attrs & GRUB_MEM_ATTR_R) ? 'r' : '-',
+                    (attrs & GRUB_MEM_ATTR_R) ? 'w' : '-',
+                    (attrs & GRUB_MEM_ATTR_R) ? 'x' : '-');
+    }
+
+  for (stack_end = stack_current + page_size ;
+       !(attrs & GRUB_MEM_ATTR_R);
+       stack_end += page_size)
+    {
+      err = grub_get_mem_attrs (stack_current, page_size, &attrs);
+      if (err)
+	{
+	  grub_dprintf ("nx",
+			"grub_get_mem_attrs(0x%"PRIxGRUB_UINT64_T", ...) -> 0x%x\n",
+			stack_current, err);
+	  grub_error_pop ();
+	  break;
+	}
+    }
+  if (stack_end > stack_current)
+    {
+      grub_stack_addr = stack_current;
+      grub_stack_size = stack_end - stack_current;
+      grub_dprintf ("nx",
+		    "detected stack from 0x%"PRIxGRUB_ADDR" to 0x%"PRIxGRUB_ADDR"\n",
+		    grub_stack_addr, grub_stack_addr + grub_stack_size - 1);
+    }
+}
+
 void
 grub_efi_mm_init (void)
 {
@@ -615,6 +691,8 @@ grub_efi_mm_init (void)
   grub_efi_uint64_t required_pages;
   int mm_status;
 
+  grub_nx_init ();
+
   /* Prepare a memory region to store two memory maps.  */
   memory_map = grub_efi_allocate_any_pages (2 * BYTES_TO_PAGES (MEMORY_MAP_SIZE));
   if (! memory_map)
diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c
index 24ab0f0074..37f5d0c7eb 100644
--- a/grub-core/loader/arm64/linux.c
+++ b/grub-core/loader/arm64/linux.c
@@ -191,7 +191,8 @@ free_params (void)
 }
 
 grub_err_t
-grub_armxx_efi_linux_boot_image (grub_addr_t addr, char *args)
+grub_armxx_efi_linux_boot_image (grub_addr_t addr, grub_size_t size, char *args,
+				int nx_supported)
 {
   grub_err_t retval;
 
@@ -201,7 +202,8 @@ grub_armxx_efi_linux_boot_image (grub_addr_t addr, char *args)
 
   grub_dprintf ("linux", "linux command line: '%s'\n", args);
 
-  retval = grub_efi_linux_boot ((char *)addr, handover_offset, (void *)addr);
+  retval = grub_efi_linux_boot (addr, size, handover_offset,
+				(void *)addr, nx_supported);
 
   /* Never reached... */
   free_params();
@@ -211,7 +213,10 @@ grub_armxx_efi_linux_boot_image (grub_addr_t addr, char *args)
 static grub_err_t
 grub_linux_boot (void)
 {
-  return grub_armxx_efi_linux_boot_image((grub_addr_t)kernel_addr, linux_args);
+  return grub_armxx_efi_linux_boot_image((grub_addr_t)kernel_addr,
+					(grub_size_t)kernel_size,
+					linux_args,
+					0);
 }
 
 static grub_err_t
@@ -340,6 +345,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   struct grub_armxx_linux_pe_header *pe;
   int rc;
   grub_err_t err;
+  int nx_supported = 1;
 
   grub_dl_ref (my_mod);
 
@@ -395,6 +401,10 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
 	}
     }
 
+  err = grub_efi_check_nx_image_support((grub_addr_t) kernel_addr, kernel_size, &nx_supported);
+  if (err != GRUB_ERR_NONE)
+    goto fail;
+
   pe = (void *)((unsigned long)kernel_addr + lh.hdr_offset);
   handover_offset = pe->opt.entry_addr;
 
diff --git a/grub-core/loader/arm64/xen_boot.c b/grub-core/loader/arm64/xen_boot.c
index 1a337866f0..1fd1bbb4bd 100644
--- a/grub-core/loader/arm64/xen_boot.c
+++ b/grub-core/loader/arm64/xen_boot.c
@@ -266,7 +266,9 @@ xen_boot (void)
     return err;
 
   return grub_armxx_efi_linux_boot_image (xen_hypervisor->start,
-					  xen_hypervisor->cmdline);
+                                         xen_hypervisor->size,
+                                         xen_hypervisor->cmdline,
+                                         0);
 }
 
 static void
diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c
index 8e658f713e..b72e6bd5e3 100644
--- a/grub-core/loader/efi/chainloader.c
+++ b/grub-core/loader/efi/chainloader.c
@@ -1055,6 +1055,17 @@ grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)),
       goto fail;
     }
 
+  /*
+   * The OS kernel is going to set its own permissions when it takes over
+   * paging a few million instructions from now, and load_image() will set up
+   * anything that's needed based on the section headers, so there's no point
+   * in doing anything but clearing the protection bits here.
+   */
+  grub_dprintf("nx", "setting attributes for %p (%lu bytes) to %llx\n",
+	       (void *)(grub_addr_t)address, fsize, 0llu);
+  grub_update_mem_attrs (address, fsize,
+			 GRUB_MEM_ATTR_R|GRUB_MEM_ATTR_W|GRUB_MEM_ATTR_X, 0);
+
 #if defined (__i386__) || defined (__x86_64__)
   if (fsize >= (grub_ssize_t) sizeof (struct grub_macho_fat_header))
     {
diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c
index 927d89a90d..421502bd25 100644
--- a/grub-core/loader/efi/linux.c
+++ b/grub-core/loader/efi/linux.c
@@ -66,16 +66,125 @@ grub_linuxefi_secure_validate (void *data, grub_uint32_t size)
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wcast-align"
+#pragma GCC diagnostic ignored "-Wint-to-pointer-cast"
+
+grub_err_t
+grub_efi_check_nx_image_support (grub_addr_t kernel_addr,
+				 grub_size_t kernel_size,
+				 int *nx_supported)
+{
+  struct grub_dos_header *doshdr;
+  grub_size_t sz = sizeof (*doshdr);
+
+  struct grub_pe32_header_32 *pe32;
+  struct grub_pe32_header_64 *pe64;
+
+  int image_is_compatible = 0;
+  int is_64_bit;
+
+  if (kernel_size < sz)
+    return grub_error (GRUB_ERR_BAD_OS, N_("kernel is too small"));
+
+  doshdr = (void *)kernel_addr;
+
+  if ((doshdr->magic & 0xffff) != GRUB_DOS_MAGIC)
+    return grub_error (GRUB_ERR_BAD_OS, N_("kernel DOS magic is invalid"));
+
+  sz = doshdr->lfanew + sizeof (*pe32);
+  if (kernel_size < sz)
+    return grub_error (GRUB_ERR_BAD_OS, N_("kernel is too small"));
+
+  pe32 = (struct grub_pe32_header_32 *)(kernel_addr + doshdr->lfanew);
+  pe64 = (struct grub_pe32_header_64 *)pe32;
+
+  if (grub_memcmp (pe32->signature, GRUB_PE32_SIGNATURE,
+		   GRUB_PE32_SIGNATURE_SIZE) != 0)
+    return grub_error (GRUB_ERR_BAD_OS, N_("kernel PE magic is invalid"));
+
+  switch (pe32->coff_header.machine)
+    {
+    case GRUB_PE32_MACHINE_ARMTHUMB_MIXED:
+    case GRUB_PE32_MACHINE_I386:
+      is_64_bit = 0;
+      break;
+    case GRUB_PE32_MACHINE_ARM64:
+    case GRUB_PE32_MACHINE_IA64:
+    case GRUB_PE32_MACHINE_X86_64:
+      is_64_bit = 1;
+      break;
+    default:
+      return grub_error (GRUB_ERR_BAD_OS, N_("PE machine type 0x%04hx unknown"),
+			 pe32->coff_header.machine);
+    }
+
+  if (is_64_bit)
+    {
+      sz = doshdr->lfanew + sizeof (*pe64);
+      if (kernel_size < sz)
+	return grub_error (GRUB_ERR_BAD_OS, N_("kernel is too small"));
+
+      if (pe64->optional_header.dll_characteristics & GRUB_PE32_NX_COMPAT)
+	image_is_compatible = 1;
+    }
+  else
+    {
+      if (pe32->optional_header.dll_characteristics & GRUB_PE32_NX_COMPAT)
+	image_is_compatible = 1;
+    }
+
+  *nx_supported = image_is_compatible;
+  return GRUB_ERR_NONE;
+}
+
+grub_err_t
+grub_efi_check_nx_required (int *nx_required)
+{
+  grub_efi_status_t status;
+  grub_efi_guid_t guid = GRUB_EFI_SHIM_LOCK_GUID;
+  grub_size_t mok_policy_sz = 0;
+  char *mok_policy = NULL;
+  grub_uint32_t mok_policy_attrs = 0;
+
+  status = grub_efi_get_variable_with_attributes ("MokPolicy", &guid,
+						  &mok_policy_sz,
+						  (void **)&mok_policy,
+						  &mok_policy_attrs);
+  if (status == GRUB_EFI_NOT_FOUND ||
+      mok_policy_sz == 0 ||
+      mok_policy == NULL)
+    {
+      *nx_required = 0;
+      return GRUB_ERR_NONE;
+    }
+
+  *nx_required = 0;
+  if (mok_policy_sz < 1 ||
+      mok_policy_attrs != (GRUB_EFI_VARIABLE_BOOTSERVICE_ACCESS |
+			   GRUB_EFI_VARIABLE_RUNTIME_ACCESS) ||
+      (mok_policy[mok_policy_sz-1] & GRUB_MOK_POLICY_NX_REQUIRED))
+    *nx_required = 1;
+
+  return GRUB_ERR_NONE;
+}
 
 typedef void (*handover_func) (void *, grub_efi_system_table_t *, void *);
 
 grub_err_t
-grub_efi_linux_boot (void *kernel_addr, grub_off_t handover_offset,
-		     void *kernel_params)
+grub_efi_linux_boot (grub_addr_t kernel_addr, grub_size_t kernel_size,
+		     grub_off_t handover_offset, void *kernel_params,
+		     int nx_supported)
 {
   grub_efi_loaded_image_t *loaded_image = NULL;
   handover_func hf;
   int offset = 0;
+  grub_uint64_t stack_set_attrs = GRUB_MEM_ATTR_R |
+				  GRUB_MEM_ATTR_W |
+				  GRUB_MEM_ATTR_X;
+  grub_uint64_t stack_clear_attrs = 0;
+  grub_uint64_t kernel_set_attrs = stack_set_attrs;
+  grub_uint64_t kernel_clear_attrs = stack_clear_attrs;
+  grub_uint64_t attrs;
+  int nx_required = 0;
 
 #ifdef __x86_64__
   offset = 512;
@@ -88,12 +197,57 @@ grub_efi_linux_boot (void *kernel_addr, grub_off_t handover_offset,
    */
   loaded_image = grub_efi_get_loaded_image (grub_efi_image_handle);
   if (loaded_image)
-    loaded_image->image_base = kernel_addr;
+    loaded_image->image_base = (void *)kernel_addr;
   else
     grub_dprintf ("linux", "Loaded Image base address could not be set\n");
 
   grub_dprintf ("linux", "kernel_addr: %p handover_offset: %p params: %p\n",
-		kernel_addr, (void *)(grub_efi_uintn_t)handover_offset, kernel_params);
+		(void *)kernel_addr, (void *)handover_offset, kernel_params);
+
+
+  if (nx_required && !nx_supported)
+    return grub_error (GRUB_ERR_BAD_OS, N_("kernel does not support NX loading required by policy"));
+
+  if (nx_supported)
+    {
+      kernel_set_attrs &= ~GRUB_MEM_ATTR_W;
+      kernel_clear_attrs |= GRUB_MEM_ATTR_W;
+      stack_set_attrs &= ~GRUB_MEM_ATTR_X;
+      stack_clear_attrs |= GRUB_MEM_ATTR_X;
+    }
+
+  grub_dprintf ("nx", "Setting attributes for 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR" to r%cx\n",
+		    kernel_addr, kernel_addr + kernel_size - 1,
+		    (kernel_set_attrs & GRUB_MEM_ATTR_W) ? 'w' : '-');
+  grub_update_mem_attrs (kernel_addr, kernel_size,
+			 kernel_set_attrs, kernel_clear_attrs);
+
+  grub_get_mem_attrs (kernel_addr, 4096, &attrs);
+  grub_dprintf ("nx", "permissions for 0x%"PRIxGRUB_ADDR" are %s%s%s\n",
+		(grub_addr_t)kernel_addr,
+		(attrs & GRUB_MEM_ATTR_R) ? "r" : "-",
+		(attrs & GRUB_MEM_ATTR_W) ? "w" : "-",
+		(attrs & GRUB_MEM_ATTR_X) ? "x" : "-");
+  if (grub_stack_addr != (grub_addr_t)-1ll)
+    {
+      grub_dprintf ("nx", "Setting attributes for stack at 0x%"PRIxGRUB_ADDR"-0x%"PRIxGRUB_ADDR" to rw%c\n",
+		    grub_stack_addr, grub_stack_addr + grub_stack_size - 1,
+		    (stack_set_attrs & GRUB_MEM_ATTR_X) ? 'x' : '-');
+      grub_update_mem_attrs (grub_stack_addr, grub_stack_size,
+			     stack_set_attrs, stack_clear_attrs);
+
+      grub_get_mem_attrs (grub_stack_addr, 4096, &attrs);
+      grub_dprintf ("nx", "permissions for 0x%"PRIxGRUB_ADDR" are %s%s%s\n",
+		    grub_stack_addr,
+		    (attrs & GRUB_MEM_ATTR_R) ? "r" : "-",
+		    (attrs & GRUB_MEM_ATTR_W) ? "w" : "-",
+		    (attrs & GRUB_MEM_ATTR_X) ? "x" : "-");
+    }
+
+#if defined(__i386__) || defined(__x86_64__)
+  asm volatile ("cli");
+#endif
+
   hf = (handover_func)((char *)kernel_addr + handover_offset + offset);
   grub_dprintf ("linux", "handover_func() = %p\n", hf);
   hf (grub_efi_image_handle, grub_efi_system_table, kernel_params);
diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
index 3d4069e4c6..d80d6ec312 100644
--- a/grub-core/loader/i386/efi/linux.c
+++ b/grub-core/loader/i386/efi/linux.c
@@ -44,7 +44,7 @@ struct grub_linuxefi_context {
   grub_uint32_t handover_offset;
   struct linux_kernel_params *params;
   char *cmdline;
-
+  int nx_supported;
   void *initrd_mem;
 };
 
@@ -110,13 +110,19 @@ kernel_alloc(grub_efi_uintn_t size,
       pages = BYTES_TO_PAGES(size);
       grub_dprintf ("linux", "Trying to allocate %lu pages from %p\n",
 		    pages, (void *)max);
+      size = pages * GRUB_EFI_PAGE_SIZE;
 
       prev_max = max;
       addr = grub_efi_allocate_pages_real (max, pages,
 					   max_addresses[i].alloc_type,
 					   memtype);
       if (addr)
-	grub_dprintf ("linux", "Allocated at %p\n", addr);
+	{
+	  grub_dprintf ("linux", "Allocated at %p\n", addr);
+	  grub_update_mem_attrs ((grub_addr_t)addr, size,
+				 GRUB_MEM_ATTR_R|GRUB_MEM_ATTR_W,
+				 GRUB_MEM_ATTR_X);
+	}
     }
 
   while (grub_error_pop ())
@@ -137,9 +143,11 @@ grub_linuxefi_boot (void *data)
 
   asm volatile ("cli");
 
-  return grub_efi_linux_boot ((char *)context->kernel_mem,
+  return grub_efi_linux_boot ((grub_addr_t)context->kernel_mem,
+			      context->kernel_size,
 			      context->handover_offset,
-			      context->params);
+			      context->params,
+			      context->nx_supported);
 }
 
 static grub_err_t
@@ -308,7 +316,9 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   grub_uint32_t handover_offset;
   struct linux_kernel_params *params = 0;
   char *cmdline = 0;
+  int nx_supported = 1;
   struct grub_linuxefi_context *context = 0;
+  grub_err_t err;
 
   grub_dl_ref (my_mod);
 
@@ -352,6 +362,13 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
 	}
     }
 
+  err = grub_efi_check_nx_image_support ((grub_addr_t)kernel, filelen,
+					 &nx_supported);
+  if (err != GRUB_ERR_NONE)
+    return err;
+  grub_dprintf ("linux", "nx is%s supported by this kernel\n",
+		nx_supported ? "" : " not");
+
   lh = (struct linux_i386_kernel_header *)kernel;
   grub_dprintf ("linux", "original lh is at %p\n", kernel);
 
@@ -515,6 +532,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   context->handover_offset = handover_offset;
   context->params = params;
   context->cmdline = cmdline;
+  context->nx_supported = nx_supported;
 
   grub_loader_set_ex (grub_linuxefi_boot, grub_linuxefi_unload, context, 0);
 
diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
index ef8fcb9e1b..c160ddb0ea 100644
--- a/grub-core/loader/i386/linux.c
+++ b/grub-core/loader/i386/linux.c
@@ -831,6 +831,11 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   grub_memset (&linux_params, 0, sizeof (linux_params));
   grub_memcpy (&linux_params.setup_sects, &lh.setup_sects, sizeof (lh) - 0x1F1);
 
+  grub_dprintf("efi", "setting attributes for %p (%zu bytes) to +rw-x\n",
+	       &linux_params, sizeof (lh) + len);
+  grub_update_mem_attrs ((grub_addr_t)&linux_params, sizeof (lh) + len,
+			 GRUB_MEM_ATTR_R|GRUB_MEM_ATTR_W, GRUB_MEM_ATTR_X);
+
   linux_params.code32_start = prot_mode_target + lh.code32_start - GRUB_LINUX_BZIMAGE_ADDR;
   linux_params.kernel_alignment = (1 << align);
   linux_params.ps_mouse = linux_params.padding10 =  0;
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index a635bcb0a9..8ca8c38f9a 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -135,12 +135,16 @@ extern void (*EXPORT_VAR(grub_efi_net_config)) (grub_efi_handle_t hnd,
 						char **device,
 						char **path);
 
+extern grub_addr_t EXPORT_VAR(grub_stack_addr);
+extern grub_size_t EXPORT_VAR(grub_stack_size);
+
 #if defined(__arm__) || defined(__aarch64__)
 void *EXPORT_FUNC(grub_efi_get_firmware_fdt)(void);
 grub_err_t EXPORT_FUNC(grub_efi_get_ram_base)(grub_addr_t *);
 #include <grub/cpu/linux.h>
 grub_err_t grub_armxx_efi_linux_check_image(struct linux_armxx_kernel_header *lh);
-grub_err_t grub_armxx_efi_linux_boot_image(grub_addr_t addr, char *args);
+grub_err_t grub_armxx_efi_linux_boot_image(grub_addr_t addr, grub_size_t size,
+					  char *args, int nx_enabled);
 #endif
 
 grub_addr_t grub_efi_section_addr (const char *section);
diff --git a/include/grub/efi/linux.h b/include/grub/efi/linux.h
index 0033d9305a..8130b19590 100644
--- a/include/grub/efi/linux.h
+++ b/include/grub/efi/linux.h
@@ -22,10 +22,23 @@
 #include <grub/err.h>
 #include <grub/symbol.h>
 
+#define GRUB_MOK_POLICY_NX_REQUIRED   0x1
+
 int
 EXPORT_FUNC(grub_linuxefi_secure_validate) (void *data, grub_uint32_t size);
+
 grub_err_t
-EXPORT_FUNC(grub_efi_linux_boot) (void *kernel_address, grub_off_t offset,
-				  void *kernel_param);
+EXPORT_FUNC(grub_efi_linux_boot) (grub_addr_t kernel_address,
+				  grub_size_t kernel_size,
+				  grub_off_t handover_offset,
+				  void *kernel_param, int nx_enabled);
+
+grub_err_t
+EXPORT_FUNC(grub_efi_check_nx_image_support) (grub_addr_t kernel_addr,
+					      grub_size_t kernel_size,
+					      int *nx_supported);
+
+grub_err_t
+EXPORT_FUNC(grub_efi_check_nx_required) (int *nx_required);
 
 #endif /* ! GRUB_EFI_LINUX_HEADER */
diff --git a/include/grub/efi/pe32.h b/include/grub/efi/pe32.h
index 2241f6317b..45c9f8b756 100644
--- a/include/grub/efi/pe32.h
+++ b/include/grub/efi/pe32.h
@@ -172,6 +172,8 @@ struct grub_pe32_optional_header
   struct grub_pe32_data_directory reserved_entry;
 };
 
+#define GRUB_PE32_NX_COMPAT 0x0100
+
 struct grub_pe64_optional_header
 {
   grub_uint16_t magic;