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EFI fixes (take #2)

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- Use the right variable to check for shim insecure mode
 - Wipe setup_data field when booting via EFI
 - Add missing error check to efibc driver
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Merge tag 'efi-urgent-for-v6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI fixes from Ard Biesheuvel:

 - Use the right variable to check for shim insecure mode

 - Wipe setup_data field when booting via EFI

 - Add missing error check to efibc driver

* tag 'efi-urgent-for-v6.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi: libstub: check Shim mode using MokSBStateRT
  efi: x86: Wipe setup_data on pure EFI boot
  efi: efibc: Guard against allocation failure
This commit is contained in:
Linus Torvalds 2022-09-22 10:27:38 -07:00
commit 129e715218
3 changed files with 14 additions and 4 deletions
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3
drivers/firmware/efi/efibc.c
View File

@ -48,6 +48,9 @@ static int efibc_reboot_notifier_call(struct notifier_block *notifier,
return NOTIFY_DONE;
wdata = kmalloc(MAX_DATA_LEN * sizeof(efi_char16_t), GFP_KERNEL);
if (!wdata)
return NOTIFY_DONE;
for (l = 0; l < MAX_DATA_LEN - 1 && str[l] != '\0'; l++)
wdata[l] = str[l];
wdata[l] = L'\0';

8
drivers/firmware/efi/libstub/secureboot.c
View File

@ -14,7 +14,7 @@
/* SHIM variables */
static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID;
static const efi_char16_t shim_MokSBState_name[] = L"MokSBState";
static const efi_char16_t shim_MokSBState_name[] = L"MokSBStateRT";
static efi_status_t get_var(efi_char16_t *name, efi_guid_t *vendor, u32 *attr,
unsigned long *data_size, void *data)
@ -43,8 +43,8 @@ enum efi_secureboot_mode efi_get_secureboot(void)
/*
* See if a user has put the shim into insecure mode. If so, and if the
* variable doesn't have the runtime attribute set, we might as well
* honor that.
* variable doesn't have the non-volatile attribute set, we might as
* well honor that.
*/
size = sizeof(moksbstate);
status = get_efi_var(shim_MokSBState_name, &shim_guid,
@ -53,7 +53,7 @@ enum efi_secureboot_mode efi_get_secureboot(void)
/* If it fails, we don't care why. Default to secure */
if (status != EFI_SUCCESS)
goto secure_boot_enabled;
if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) && moksbstate == 1)
if (!(attr & EFI_VARIABLE_NON_VOLATILE) && moksbstate == 1)
return efi_secureboot_mode_disabled;
secure_boot_enabled:

7
drivers/firmware/efi/libstub/x86-stub.c
View File

@ -516,6 +516,13 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
hdr->ramdisk_image = 0;
hdr->ramdisk_size = 0;
/*
* Disregard any setup data that was provided by the bootloader:
* setup_data could be pointing anywhere, and we have no way of
* authenticating or validating the payload.
*/
hdr->setup_data = 0;
efi_stub_entry(handle, sys_table_arg, boot_params);
/* not reached */