[PATCH 6/7] efi: Handle secure boot from UEFI-2.6 [ver #7]

[David Howells]

UEFI-2.6 adds a new variable, DeployedMode.  If it exists, this must be 1
if we're to engage lockdown mode.

Reported-by: James Bottomley <james.bottom...@hansenpartnership.com>
Signed-off-by: David Howells <dhowe...@redhat.com>
---

 drivers/firmware/efi/libstub/secureboot.c |   16 +++++++++++++++-
 include/linux/efi.h                       |    4 ++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/secureboot.c 
b/drivers/firmware/efi/libstub/secureboot.c
index 39c91e091f6a..d653f76b9725 100644
--- a/drivers/firmware/efi/libstub/secureboot.c
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -22,6 +22,9 @@ static const efi_char16_t const efi_SecureBoot_name[] = {
 static const efi_char16_t const efi_SetupMode_name[] = {
        'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
 };
+static const efi_char16_t const efi_DeployedMode_name[] = {
+       'D', 'e', 'p', 'l', 'o', 'y', 'e', 'd', 'M', 'o', 'd', 'e', 0
+};
 
 /* SHIM variables */
 static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
@@ -40,7 +43,7 @@ static efi_char16_t const shim_MokSBState_name[] = {
 enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
 {
        u32 attr;
-       u8 secboot, setupmode, moksbstate;
+       u8 secboot, setupmode, deployedmode, moksbstate;
        unsigned long size;
        efi_status_t status;
 
@@ -59,6 +62,17 @@ enum efi_secureboot_mode 
efi_get_secureboot(efi_system_table_t *sys_table_arg)
        if (secboot == 0 || setupmode == 1)
                return efi_secureboot_mode_disabled;
 
+       /* UEFI-2.6 requires DeployedMode to be 1. */
+       if (sys_table_arg->hdr.revision >= EFI_2_60_SYSTEM_TABLE_REVISION) {
+               size = sizeof(deployedmode);
+               status = get_efi_var(efi_DeployedMode_name, &efi_variable_guid,
+                                    NULL, &size, &deployedmode);
+               if (status != EFI_SUCCESS)
+                       goto out_efi_err;
+               if (deployedmode == 0)
+                       return efi_secureboot_mode_disabled;
+       }
+
        /* See if a user has put shim into insecure mode.  If so, and if the
         * variable doesn't have the runtime attribute set, we might as well
         * honor that.
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 1c200cdbdc05..87c1a6993f17 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -646,6 +646,10 @@ typedef struct {
 
 #define EFI_SYSTEM_TABLE_SIGNATURE ((u64)0x5453595320494249ULL)
 
+#define EFI_2_60_SYSTEM_TABLE_REVISION  ((2 << 16) | (60))
+#define EFI_2_50_SYSTEM_TABLE_REVISION  ((2 << 16) | (50))
+#define EFI_2_40_SYSTEM_TABLE_REVISION  ((2 << 16) | (40))
+#define EFI_2_31_SYSTEM_TABLE_REVISION  ((2 << 16) | (31))
 #define EFI_2_30_SYSTEM_TABLE_REVISION  ((2 << 16) | (30))
 #define EFI_2_20_SYSTEM_TABLE_REVISION  ((2 << 16) | (20))
 #define EFI_2_10_SYSTEM_TABLE_REVISION  ((2 << 16) | (10))