[PATCH 6/7] efi: Handle secure boot from UEFI-2.6 [ver #7]
From: dhowells@redhat.com (David Howells)
Date: 2017-01-31 15:14:46
Also in:
linux-efi, lkml
Subsystem:
extensible firmware interface (efi), the rest · Maintainers:
Ard Biesheuvel, Linus Torvalds
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.Bottomley@HansenPartnership.com> Signed-off-by: David Howells <dhowells@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))