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Description: Don't permit loading modules on UEFI secure boot
Author: Matthew Garrett <mjg@redhat.com>
Author: Colin Watson <cjwatson@ubuntu.com>
Origin: vendor, http://pkgs.fedoraproject.org/cgit/grub2.git/tree/grub-2.00-no-insmod-on-sb.patch
Forwarded: no
Last-Update: 2013-01-02
Index: b/grub-core/kern/dl.c
===================================================================
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -42,6 +42,10 @@
#include <sys/mman.h>
#endif
+#ifdef GRUB_MACHINE_EFI
+#include <grub/efi/efi.h>
+#endif
+
#pragma GCC diagnostic ignored "-Wcast-align"
@@ -668,6 +672,15 @@
void *core = 0;
grub_dl_t mod = 0;
+#ifdef GRUB_MACHINE_EFI
+ if (grub_efi_secure_boot ())
+ {
+ grub_error (GRUB_ERR_ACCESS_DENIED,
+ "Secure Boot forbids loading module from %s", filename);
+ return 0;
+ }
+#endif
+
file = grub_file_open (filename);
if (! file)
return 0;
Index: b/grub-core/kern/efi/efi.c
===================================================================
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -259,6 +259,34 @@
return 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
Index: b/include/grub/efi/efi.h
===================================================================
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -69,6 +69,7 @@
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);
|