From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <mjg@redhat.com>

Date: Tue, 10 Jul 2012 11:58:52 -0400

Subject: [PATCH] Add support for Linux EFI stub loading.

Also:

commit 71c843745f22f81e16d259e2e19c99bf3c1855c1

Author: Colin Watson <cjwatson@ubuntu.com>

Date:   Tue Oct 23 10:40:49 2012 -0400

Don't allow insmod when secure boot is enabled.

Hi,

Fedora's patch to forbid insmod in UEFI Secure Boot environments is fine

as far as it goes.  However, the insmod command is not the only way that

modules can be loaded.  In particular, the 'normal' command, which

implements the usual GRUB menu and the fully-featured command prompt,

will implicitly load commands not currently loaded into memory.  This

permits trivial Secure Boot violations by writing commands implementing

whatever you want to do and pointing $prefix at the malicious code.

I'm currently test-building this patch (replacing your current

grub-2.00-no-insmod-on-sb.patch), but this should be more correct.  It

moves the check into grub_dl_load_file.

---

 grub-core/Makefile.core.def       |  16 +-

 grub-core/kern/dl.c               |  21 +++

 grub-core/kern/efi/efi.c          |  28 ++++

 grub-core/kern/efi/mm.c           |  32 ++++

 grub-core/loader/arm64/linux.c    | 118 +++++++-------

 grub-core/loader/arm64/xen_boot.c |   1 -

 grub-core/loader/efi/linux.c      |  70 ++++++++

 grub-core/loader/i386/efi/linux.c | 335 ++++++++++++++++++++++++++++++++++++++

 grub-core/loader/i386/pc/linux.c  |  10 +-

 include/grub/arm/linux.h          |   9 +

 include/grub/arm64/linux.h        |   9 +

 include/grub/efi/efi.h            |   7 +-

 include/grub/efi/linux.h          |  31 ++++

 13 files changed, 618 insertions(+), 69 deletions(-)

 create mode 100644 grub-core/loader/efi/linux.c

 create mode 100644 grub-core/loader/i386/efi/linux.c

 create mode 100644 include/grub/efi/linux.h

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def

index 8022e1c0a79..45d3edaa4dc 100644

--- a/grub-core/Makefile.core.def

+++ b/grub-core/Makefile.core.def

@@ -1734,13 +1734,6 @@ module = {

   enable = i386_pc;

 };

-

-module = {

-  name = linux16;

-  common = loader/i386/pc/linux.c;

-  enable = x86;

-};

-

 module = {

   name = ntldr;

   i386_pc = loader/i386/pc/ntldr.c;

@@ -1796,7 +1789,9 @@ module = {

 module = {

   name = linux;

-  x86 = loader/i386/linux.c;

+  i386_pc = loader/i386/pc/linux.c;

+  x86_64_efi = loader/i386/efi/linux.c;

+  i386_efi = loader/i386/efi/linux.c;

   i386_xen_pvh = loader/i386/linux.c;

   xen = loader/i386/xen.c;

   i386_pc = lib/i386/pc/vesa_modes_table.c;

@@ -1811,9 +1806,14 @@ module = {

   arm64 = loader/arm64/linux.c;

   riscv32 = loader/riscv/linux.c;

   riscv64 = loader/riscv/linux.c;

+  emu = loader/emu/linux.c;

+  fdt = lib/fdt.c;

+

   common = loader/linux.c;

   common = lib/cmdline.c;

   enable = noemu;

+

+  efi = loader/efi/linux.c;

 };

 module = {

diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c

index 48f8a79073d..b7149370950 100644

--- a/grub-core/kern/dl.c

+++ b/grub-core/kern/dl.c

@@ -38,6 +38,14 @@

 #define GRUB_MODULES_MACHINE_READONLY

 #endif

+#ifdef GRUB_MACHINE_EMU

+#include <sys/mman.h>

+#endif

+

+#ifdef GRUB_MACHINE_EFI

+#include <grub/efi/efi.h>

+#endif

+

 #pragma GCC diagnostic ignored "-Wcast-align"

@@ -695,6 +703,19 @@ grub_dl_load_file (const char *filename)

   void *core = 0;

   grub_dl_t mod = 0;

+#ifdef GRUB_MACHINE_EFI

+  if (grub_efi_secure_boot ())

+    {

+#if 0

+      /* This is an error, but grub2-mkconfig still generates a pile of

+       * insmod commands, so emitting it would be mostly just obnoxious. */

+      grub_error (GRUB_ERR_ACCESS_DENIED,

+		  "Secure Boot forbids loading module from %s", filename);

+#endif

+      return 0;

+    }

+#endif

+

   grub_boot_time ("Loading module %s", filename);

   file = grub_file_open (filename, GRUB_FILE_TYPE_GRUB_MODULE);

diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c

index 8cff7be0289..35b8f670602 100644

--- a/grub-core/kern/efi/efi.c

+++ b/grub-core/kern/efi/efi.c

@@ -286,6 +286,34 @@ grub_efi_get_variable (const char *var, const grub_efi_guid_t *guid,

   return grub_efi_get_variable_with_attributes (var, guid, datasize_out, data_out, NULL);

 }

+grub_efi_boolean_t

+grub_efi_secure_boot (void)

+{

+  grub_efi_guid_t efi_var_guid = GRUB_EFI_GLOBAL_VARIABLE_GUID;

+  grub_size_t datasize;

+  char *secure_boot = NULL;

+  char *setup_mode = NULL;

+  grub_efi_boolean_t ret = 0;

+

+  secure_boot = grub_efi_get_variable("SecureBoot", &efi_var_guid, &datasize);

+

+  if (datasize != 1 || !secure_boot)

+    goto out;

+

+  setup_mode = grub_efi_get_variable("SetupMode", &efi_var_guid, &datasize);

+

+  if (datasize != 1 || !setup_mode)

+    goto out;

+

+  if (*secure_boot && !*setup_mode)

+    ret = 1;

+

+ out:

+  grub_free (secure_boot);

+  grub_free (setup_mode);

+  return ret;

+}

+

 #pragma GCC diagnostic ignored "-Wcast-align"

 /* Search the mods section from the PE32/PE32+ image. This code uses

diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c

index 9838fb2f50d..f6aef0ef649 100644

--- a/grub-core/kern/efi/mm.c

+++ b/grub-core/kern/efi/mm.c

@@ -113,6 +113,38 @@ grub_efi_drop_alloc (grub_efi_physical_address_t address,

     }

 }

+/* Allocate pages below a specified address */

+void *

+grub_efi_allocate_pages_max (grub_efi_physical_address_t max,

+			     grub_efi_uintn_t pages)

+{

+  grub_efi_status_t status;

+  grub_efi_boot_services_t *b;

+  grub_efi_physical_address_t address = max;

+

+  if (max > 0xffffffff)

+    return 0;

+

+  b = grub_efi_system_table->boot_services;

+  status = efi_call_4 (b->allocate_pages, GRUB_EFI_ALLOCATE_MAX_ADDRESS, GRUB_EFI_LOADER_DATA, pages, &address);

+

+  if (status != GRUB_EFI_SUCCESS)

+    return 0;

+

+  if (address == 0)

+    {

+      /* Uggh, the address 0 was allocated... This is too annoying,

+	 so reallocate another one.  */

+      address = max;

+      status = efi_call_4 (b->allocate_pages, GRUB_EFI_ALLOCATE_MAX_ADDRESS, GRUB_EFI_LOADER_DATA, pages, &address);

+      grub_efi_free_pages (0, pages);

+      if (status != GRUB_EFI_SUCCESS)

+	return 0;

+    }

+

+  return (void *) ((grub_addr_t) address);

+}

+

 /* Allocate pages. Return the pointer to the first of allocated pages.  */

 void *

 grub_efi_allocate_pages_real (grub_efi_physical_address_t address,

diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c

index ef3e9f9444c..a312c668685 100644

--- a/grub-core/loader/arm64/linux.c

+++ b/grub-core/loader/arm64/linux.c

@@ -29,6 +29,7 @@

 #include <grub/efi/efi.h>

 #include <grub/efi/fdtload.h>

 #include <grub/efi/memory.h>

+#include <grub/efi/linux.h>

 #include <grub/efi/pe32.h>

 #include <grub/i18n.h>

 #include <grub/lib/cmdline.h>

@@ -41,6 +42,7 @@ static int loaded;

 static void *kernel_addr;

 static grub_uint64_t kernel_size;

+static grub_uint32_t handover_offset;

 static char *linux_args;

 static grub_uint32_t cmdline_size;

@@ -67,7 +69,8 @@ grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh)

 static grub_err_t

 finalize_params_linux (void)

 {

-  int node, retval;

+  grub_efi_loaded_image_t *loaded_image = NULL;

+  int node, retval, len;

   void *fdt;

@@ -102,79 +105,70 @@ finalize_params_linux (void)

   if (grub_fdt_install() != GRUB_ERR_NONE)

     goto failure;

-  return GRUB_ERR_NONE;

-

-failure:

-  grub_fdt_unload();

-  return grub_error(GRUB_ERR_BAD_OS, "failed to install/update FDT");

-}

-

-grub_err_t

-grub_arch_efi_linux_boot_image (grub_addr_t addr, grub_size_t size, char *args)

-{

-  grub_efi_memory_mapped_device_path_t *mempath;

-  grub_efi_handle_t image_handle;

-  grub_efi_boot_services_t *b;

-  grub_efi_status_t status;

-  grub_efi_loaded_image_t *loaded_image;

-  int len;

-

-  mempath = grub_malloc (2 * sizeof (grub_efi_memory_mapped_device_path_t));

-  if (!mempath)

-    return grub_errno;

-

-  mempath[0].header.type = GRUB_EFI_HARDWARE_DEVICE_PATH_TYPE;

-  mempath[0].header.subtype = GRUB_EFI_MEMORY_MAPPED_DEVICE_PATH_SUBTYPE;

-  mempath[0].header.length = grub_cpu_to_le16_compile_time (sizeof (*mempath));

-  mempath[0].memory_type = GRUB_EFI_LOADER_DATA;

-  mempath[0].start_address = addr;

-  mempath[0].end_address = addr + size;

-

-  mempath[1].header.type = GRUB_EFI_END_DEVICE_PATH_TYPE;

-  mempath[1].header.subtype = GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE;

-  mempath[1].header.length = sizeof (grub_efi_device_path_t);

-

-  b = grub_efi_system_table->boot_services;

-  status = b->load_image (0, grub_efi_image_handle,

-			  (grub_efi_device_path_t *) mempath,

-			  (void *) addr, size, &image_handle);

-  if (status != GRUB_EFI_SUCCESS)

-    return grub_error (GRUB_ERR_BAD_OS, "cannot load image");

-

-  grub_dprintf ("linux", "linux command line: '%s'\n", args);

+  grub_dprintf ("linux", "Installed/updated FDT configuration table @ %p\n",

+                fdt);

   /* Convert command line to UCS-2 */

-  loaded_image = grub_efi_get_loaded_image (image_handle);

+  loaded_image = grub_efi_get_loaded_image (grub_efi_image_handle);

+  if (!loaded_image)

+    goto failure;

+

   loaded_image->load_options_size = len =

-    (grub_strlen (args) + 1) * sizeof (grub_efi_char16_t);

+    (grub_strlen (linux_args) + 1) * sizeof (grub_efi_char16_t);

   loaded_image->load_options =

     grub_efi_allocate_any_pages (GRUB_EFI_BYTES_TO_PAGES (loaded_image->load_options_size));

   if (!loaded_image->load_options)

-    return grub_errno;

+    return grub_error(GRUB_ERR_BAD_OS, "failed to create kernel parameters");

   loaded_image->load_options_size =

     2 * grub_utf8_to_utf16 (loaded_image->load_options, len,

-			    (grub_uint8_t *) args, len, NULL);

+                           (grub_uint8_t *) linux_args, len, NULL);

-  grub_dprintf ("linux", "starting image %p\n", image_handle);

-  status = b->start_image (image_handle, 0, NULL);

+  return GRUB_ERR_NONE;

-  /* When successful, not reached */

-  b->unload_image (image_handle);

-  grub_efi_free_pages ((grub_addr_t) loaded_image->load_options,

-		       GRUB_EFI_BYTES_TO_PAGES (loaded_image->load_options_size));

+failure:

+  grub_fdt_unload();

+  return grub_error(GRUB_ERR_BAD_OS, "failed to install/update FDT");

+}

-  return grub_errno;

+static void

+free_params (void)

+{

+  grub_efi_loaded_image_t *loaded_image = NULL;

+

+  loaded_image = grub_efi_get_loaded_image (grub_efi_image_handle);

+  if (loaded_image)

+    {

+      if (loaded_image->load_options)

+       grub_efi_free_pages ((grub_efi_physical_address_t)(grub_efi_uintn_t)loaded_image->load_options,

+                            GRUB_EFI_BYTES_TO_PAGES (loaded_image->load_options_size));

+      loaded_image->load_options = NULL;

+      loaded_image->load_options_size = 0;

+    }

+}

+

+grub_err_t

+grub_arch_efi_linux_boot_image (grub_addr_t addr, char *args)

+{

+  grub_err_t retval;

+

+  retval = finalize_params_linux ();

+  if (retval != GRUB_ERR_NONE)

+    return grub_errno;

+

+  grub_dprintf ("linux", "linux command line: '%s'\n", args);

+

+  retval = grub_efi_linux_boot ((char *)addr, handover_offset, (void *)addr);

+

+  /* Never reached... */

+  free_params();

+  return retval;

 }

 static grub_err_t

 grub_linux_boot (void)

 {

-  if (finalize_params_linux () != GRUB_ERR_NONE)

-    return grub_errno;

-

-  return (grub_arch_efi_linux_boot_image((grub_addr_t)kernel_addr,

-                                          kernel_size, linux_args));

+  return (grub_arch_efi_linux_boot_image((grub_addr_t)kernel_addr, linux_args));

 }

 static grub_err_t

@@ -288,6 +282,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

 {

   grub_file_t file = 0;

   struct linux_arch_kernel_header lh;

+  struct grub_armxx_linux_pe_header *pe;

   grub_err_t err;

   grub_dl_ref (my_mod);

@@ -333,6 +328,15 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   grub_dprintf ("linux", "kernel @ %p\n", kernel_addr);

+  if (!grub_linuxefi_secure_validate (kernel_addr, kernel_size))

+    {

+      grub_error (GRUB_ERR_INVALID_COMMAND, N_("%s has invalid signature"), argv[0]);

+      goto fail;

+    }

+

+  pe = (void *)((unsigned long)kernel_addr + lh.hdr_offset);

+  handover_offset = pe->opt.entry_addr;

+

   cmdline_size = grub_loader_cmdline_size (argc, argv) + sizeof (LINUX_IMAGE);

   linux_args = grub_malloc (cmdline_size);

   if (!linux_args)

diff --git a/grub-core/loader/arm64/xen_boot.c b/grub-core/loader/arm64/xen_boot.c

index 22cc25eccd9..d9b7a9ba400 100644

--- a/grub-core/loader/arm64/xen_boot.c

+++ b/grub-core/loader/arm64/xen_boot.c

@@ -266,7 +266,6 @@ xen_boot (void)

     return err;

   return grub_arch_efi_linux_boot_image (xen_hypervisor->start,

-					  xen_hypervisor->size,

 					  xen_hypervisor->cmdline);

 }

diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c

new file mode 100644

index 00000000000..c24202a5dd1

--- /dev/null

+++ b/grub-core/loader/efi/linux.c

@@ -0,0 +1,70 @@

+/*

+ *  GRUB  --  GRand Unified Bootloader

+ *  Copyright (C) 2014 Free Software Foundation, Inc.

+ *

+ *  GRUB is free software: you can redistribute it and/or modify

+ *  it under the terms of the GNU General Public License as published by

+ *  the Free Software Foundation, either version 3 of the License, or

+ *  (at your option) any later version.

+ *

+ *  GRUB 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 General Public License for more details.

+ *

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

+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.

+ */

+

+#include <grub/err.h>

+#include <grub/mm.h>

+#include <grub/types.h>

+#include <grub/cpu/linux.h>

+#include <grub/efi/efi.h>

+#include <grub/efi/pe32.h>

+#include <grub/efi/linux.h>

+

+#define SHIM_LOCK_GUID \

+ { 0x605dab50, 0xe046, 0x4300, {0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23} }

+

+struct grub_efi_shim_lock

+{

+  grub_efi_status_t (*verify) (void *buffer, grub_uint32_t size);

+};

+typedef struct grub_efi_shim_lock grub_efi_shim_lock_t;

+

+grub_efi_boolean_t

+grub_linuxefi_secure_validate (void *data, grub_uint32_t size)

+{

+  grub_efi_guid_t guid = SHIM_LOCK_GUID;

+  grub_efi_shim_lock_t *shim_lock;

+

+  shim_lock = grub_efi_locate_protocol(&guid, NULL);

+

+  if (!shim_lock)

+    return 1;

+

+  if (shim_lock->verify(data, size) == GRUB_EFI_SUCCESS)

+    return 1;

+

+  return 0;

+}

+

+#pragma GCC diagnostic push

+#pragma GCC diagnostic ignored "-Wcast-align"

+

+typedef void (*handover_func) (void *, grub_efi_system_table_t *, void *);

+

+grub_err_t

+grub_efi_linux_boot (void *kernel_addr, grub_off_t offset,

+		     void *kernel_params)

+{

+  handover_func hf;

+

+  hf = (handover_func)((char *)kernel_addr + offset);

+  hf (grub_efi_image_handle, grub_efi_system_table, kernel_params);

+

+  return GRUB_ERR_BUG;

+}

+

+#pragma GCC diagnostic pop

diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c

new file mode 100644

index 00000000000..bb2616a8092

--- /dev/null

+++ b/grub-core/loader/i386/efi/linux.c

@@ -0,0 +1,335 @@

+/*

+ *  GRUB  --  GRand Unified Bootloader

+ *  Copyright (C) 2012  Free Software Foundation, Inc.

+ *

+ *  GRUB is free software: you can redistribute it and/or modify

+ *  it under the terms of the GNU General Public License as published by

+ *  the Free Software Foundation, either version 3 of the License, or

+ *  (at your option) any later version.

+ *

+ *  GRUB 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 General Public License for more details.

+ *

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

+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.

+ */

+

+#include <grub/loader.h>

+#include <grub/file.h>

+#include <grub/err.h>

+#include <grub/types.h>

+#include <grub/mm.h>

+#include <grub/cpu/linux.h>

+#include <grub/command.h>

+#include <grub/i18n.h>

+#include <grub/lib/cmdline.h>

+#include <grub/efi/efi.h>

+#include <grub/efi/linux.h>

+

+GRUB_MOD_LICENSE ("GPLv3+");

+

+static grub_dl_t my_mod;

+static int loaded;

+static void *kernel_mem;

+static grub_uint64_t kernel_size;

+static grub_uint8_t *initrd_mem;

+static grub_uint32_t handover_offset;

+struct linux_kernel_params *params;

+static char *linux_cmdline;

+

+#define BYTES_TO_PAGES(bytes)   (((bytes) + 0xfff) >> 12)

+

+static grub_err_t

+grub_linuxefi_boot (void)

+{

+  int offset = 0;

+

+#ifdef __x86_64__

+  offset = 512;

+#endif

+  asm volatile ("cli");

+

+  return grub_efi_linux_boot ((char *)kernel_mem, handover_offset + offset,

+			      params);

+}

+

+static grub_err_t

+grub_linuxefi_unload (void)

+{

+  grub_dl_unref (my_mod);

+  loaded = 0;

+  if (initrd_mem)

+    grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t)initrd_mem,

+			 BYTES_TO_PAGES(params->ramdisk_size));

+  if (linux_cmdline)

+    grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t)

+			 linux_cmdline,

+			 BYTES_TO_PAGES(params->cmdline_size + 1));

+  if (kernel_mem)

+    grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t)kernel_mem,

+			 BYTES_TO_PAGES(kernel_size));

+  if (params)

+    grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t)params,

+			 BYTES_TO_PAGES(16384));

+  return GRUB_ERR_NONE;

+}

+

+static grub_err_t

+grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

+                 int argc, char *argv[])

+{

+  grub_file_t *files = 0;

+  int i, nfiles = 0;

+  grub_size_t size = 0;

+  grub_uint8_t *ptr;

+

+  if (argc == 0)

+    {

+      grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));

+      goto fail;

+    }

+

+  if (!loaded)

+    {

+      grub_error (GRUB_ERR_BAD_ARGUMENT, N_("you need to load the kernel first"));

+      goto fail;

+    }

+

+  files = grub_zalloc (argc * sizeof (files[0]));

+  if (!files)

+    goto fail;

+

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

+    {

+      files[i] = grub_file_open (argv[i], GRUB_FILE_TYPE_LINUX_INITRD | GRUB_FILE_TYPE_NO_DECOMPRESS);

+      if (! files[i])

+        goto fail;

+      nfiles++;

+      size += ALIGN_UP (grub_file_size (files[i]), 4);

+    }

+

+  initrd_mem = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(size));

+  if (!initrd_mem)

+    {

+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate initrd"));

+      goto fail;

+    }

+

+  params->ramdisk_size = size;

+  params->ramdisk_image = (grub_uint32_t)(grub_addr_t) initrd_mem;

+

+  ptr = initrd_mem;

+

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

+    {

+      grub_ssize_t cursize = grub_file_size (files[i]);

+      if (grub_file_read (files[i], ptr, cursize) != cursize)

+        {

+          if (!grub_errno)

+            grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),

+                        argv[i]);

+          goto fail;

+        }

+      ptr += cursize;

+      grub_memset (ptr, 0, ALIGN_UP_OVERHEAD (cursize, 4));

+      ptr += ALIGN_UP_OVERHEAD (cursize, 4);

+    }

+

+  params->ramdisk_size = size;

+

+ fail:

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

+    grub_file_close (files[i]);

+  grub_free (files);

+

+  if (initrd_mem && grub_errno)

+    grub_efi_free_pages ((grub_efi_physical_address_t)(grub_addr_t)initrd_mem,

+			 BYTES_TO_PAGES(size));

+

+  return grub_errno;

+}

+

+static grub_err_t

+grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

+		int argc, char *argv[])

+{

+  grub_file_t file = 0;

+  struct linux_i386_kernel_header lh;

+  grub_ssize_t len, start, filelen;

+  void *kernel = NULL;

+

+  grub_dl_ref (my_mod);

+

+  if (argc == 0)

+    {

+      grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));

+      goto fail;

+    }

+

+  file = grub_file_open (argv[0], GRUB_FILE_TYPE_LINUX_KERNEL);

+  if (! file)

+    goto fail;

+

+  filelen = grub_file_size (file);

+

+  kernel = grub_malloc(filelen);

+

+  if (!kernel)

+    {

+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel buffer"));

+      goto fail;

+    }

+

+  if (grub_file_read (file, kernel, filelen) != filelen)

+    {

+      grub_error (GRUB_ERR_FILE_READ_ERROR, N_("Can't read kernel %s"), argv[0]);

+      goto fail;

+    }

+

+  if (! grub_linuxefi_secure_validate (kernel, filelen))

+    {

+      grub_error (GRUB_ERR_INVALID_COMMAND, N_("%s has invalid signature"),

+		  argv[0]);

+      goto fail;

+    }

+

+  params = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(16384));

+

+  if (! params)

+    {

+      grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate kernel parameters");

+      goto fail;

+    }

+

+  grub_memset (params, 0, 16384);

+

+  grub_memcpy (&lh, kernel, sizeof (lh));

+

+  if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))

+    {

+      grub_error (GRUB_ERR_BAD_OS, N_("invalid magic number"));

+      goto fail;

+    }

+

+  if (lh.setup_sects > GRUB_LINUX_MAX_SETUP_SECTS)

+    {

+      grub_error (GRUB_ERR_BAD_OS, N_("too many setup sectors"));

+      goto fail;

+    }

+

+  if (lh.version < grub_cpu_to_le16 (0x020b))

+    {

+      grub_error (GRUB_ERR_BAD_OS, N_("kernel too old"));

+      goto fail;

+    }

+

+  if (!lh.handover_offset)

+    {

+      grub_error (GRUB_ERR_BAD_OS, N_("kernel doesn't support EFI handover"));

+      goto fail;

+    }

+

+  grub_dprintf ("linux", "setting up cmdline\n");