From 7a65d7b558974c89f19afaf0d78b54dc0327f56c Mon Sep 17 00:00:00 2001
From: Matthew Garrett <mjg@redhat.com>
Date: Wed, 15 Aug 2012 09:53:05 -0400
Subject: [PATCH] Don't permit insmod on secure boot

---
 grub-core/kern/corecmd.c |  9 +++++++++
 grub-core/kern/efi/efi.c | 28 ++++++++++++++++++++++++++++
 include/grub/efi/efi.h   |  1 +
 3 files changed, 38 insertions(+)

diff --git a/grub-core/kern/corecmd.c b/grub-core/kern/corecmd.c
index eec575c..3df9dbd 100644
--- a/grub-core/kern/corecmd.c
+++ b/grub-core/kern/corecmd.c
@@ -28,6 +28,10 @@
 #include <grub/command.h>
 #include <grub/i18n.h>
 
+#ifdef GRUB_MACHINE_EFI
+#include <grub/efi/efi.h>
+#endif
+
 /* set ENVVAR=VALUE */
 static grub_err_t
 grub_core_cmd_set (struct grub_command *cmd __attribute__ ((unused)),
@@ -81,6 +85,13 @@ grub_core_cmd_insmod (struct grub_command *cmd __attribute__ ((unused)),
 {
   grub_dl_t mod;
 
+#ifdef GRUB_MACHINE_EFI
+  if (grub_efi_secure_boot()) {
+    //grub_printf("%s\n", N_("Secure Boot forbids insmod"));
+    return 0;
+  }
+#endif
+
   if (argc == 0)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
 
diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
index 820968f..ad7aa8d 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -259,6 +259,34 @@ grub_efi_set_variable(const char *var, const grub_efi_guid_t *guid,
   return grub_error (GRUB_ERR_IO, "could not set EFI variable `%s'", var);
 }
 
+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/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 9370fd5..a000c38 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -72,6 +72,7 @@ EXPORT_FUNC (grub_efi_set_variable) (const char *var,
 				     const grub_efi_guid_t *guid,
 				     void *data,
 				     grub_size_t datasize);
+grub_efi_boolean_t EXPORT_FUNC (grub_efi_secure_boot) (void);
 int
 EXPORT_FUNC (grub_efi_compare_device_paths) (const grub_efi_device_path_t *dp1,
 					     const grub_efi_device_path_t *dp2);
-- 
1.7.11.2