Re: [edk2-devel] [PATCH v2 6/6] SecurityPkg: Add option to reset secure boot keys.

["Pete Batard" <pete@akeo.ie>]

On 2021.06.01 14:12, Grzegorz Bernacki wrote:
> This commit add option which allows reset content of Secure Boot
> keys and databases to default variables.
> 
> Signed-off-by: Grzegorz Bernacki <gjb@semihalf.com>
> ---
>   SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf     |   1 +
>   SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigNvData.h    |   2 +
>   SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfig.vfr        |   6 +
>   SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c      | 154 ++++++++++++++++++++
>   SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigStrings.uni |   4 +
>   5 files changed, 167 insertions(+)
> 
> diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
> index 30d9cd8025..bd8d256dde 100644
> --- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
> +++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigDxe.inf
> @@ -109,6 +109,7 @@
>   [Protocols]
>     gEfiHiiConfigAccessProtocolGuid               ## PRODUCES
>     gEfiDevicePathProtocolGuid                    ## PRODUCES
> +  gEfiHiiPopupProtocolGuid
>   
>   [Depex]
>     gEfiHiiConfigRoutingProtocolGuid  AND
> diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigNvData.h b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigNvData.h
> index 6e54a4b0f2..4ecc25efc3 100644
> --- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigNvData.h
> +++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigNvData.h
> @@ -54,6 +54,8 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
>   
>   #define KEY_VALUE_FROM_DBX_TO_LIST_FORM       0x100f
>   
> +#define KEY_SECURE_BOOT_RESET_TO_DEFAULT      0x1010
> +
>   #define KEY_SECURE_BOOT_OPTION                0x1100
>   #define KEY_SECURE_BOOT_PK_OPTION             0x1101
>   #define KEY_SECURE_BOOT_KEK_OPTION            0x1102
> diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfig.vfr b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfig.vfr
> index fa7e11848c..e4560c592c 100644
> --- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfig.vfr
> +++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfig.vfr
> @@ -69,6 +69,12 @@ formset
>       endif;
>       endif;
>   
> +    text
> +      help   = STRING_TOKEN(STR_SECURE_RESET_TO_DEFAULTS_HELP),
> +      text   = STRING_TOKEN(STR_SECURE_RESET_TO_DEFAULTS),
> +      flags  = INTERACTIVE,
> +      key    = KEY_SECURE_BOOT_RESET_TO_DEFAULT;
> +
>     endform;
>   
>     //
> diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
> index 67e5e594ed..47f281873b 100644
> --- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
> +++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
> @@ -8,6 +8,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
>   **/
>   
>   #include "SecureBootConfigImpl.h"
> +#include <Protocol/HiiPopup.h>
>   #include <Library/BaseCryptLib.h>
>   #include <Library/SecureBootVariableLib.h>
>   
> @@ -4154,6 +4155,132 @@ ON_EXIT:
>     return Status;
>   }
>   
> +/**
> +  This function reinitializes Secure Boot variables with default values.
> +
> +  @retval   EFI_SUCCESS           Success to update the signature list page
> +  @retval   others                Fail to delete or enroll signature data.
> +**/
> +
> +STATIC EFI_STATUS
> +EFIAPI
> +KeyEnrollReset (
> +  VOID
> +  )
> +{
> +  EFI_STATUS  Status;
> +  UINT8       SetupMode;
> +
> +  Status = EFI_SUCCESS;
> +
> +  Status = SetSecureBootMode (CUSTOM_SECURE_BOOT_MODE);
> +  if (EFI_ERROR(Status)) {
> +    return Status;
> +  }
> +
> +  // Clear all the keys and databases
> +  Status = DeleteDb ();
> +  if (EFI_ERROR (Status) && (Status != EFI_NOT_FOUND)) {
> +    DEBUG ((DEBUG_ERROR, "Fail to clear DB: %r\n", Status));
> +    return Status;
> +  }
> +
> +  Status = DeleteDbx ();
> +  if (EFI_ERROR (Status) && (Status != EFI_NOT_FOUND)) {
> +    DEBUG ((DEBUG_ERROR, "Fail to clear DBX: %r\n", Status));
> +    return Status;
> +  }
> +
> +  Status = DeleteDbt ();
> +  if (EFI_ERROR (Status) && (Status != EFI_NOT_FOUND)) {
> +    DEBUG ((DEBUG_ERROR, "Fail to clear DBT: %r\n", Status));
> +    return Status;
> +  }
> +
> +  Status = DeleteKEK ();
> +  if (EFI_ERROR (Status) && (Status != EFI_NOT_FOUND)) {
> +    DEBUG ((DEBUG_ERROR, "Fail to clear KEK: %r\n", Status));
> +    return Status;
> +  }
> +
> +  Status = DeletePlatformKey ();
> +  if (EFI_ERROR (Status) && (Status != EFI_NOT_FOUND)) {
> +    DEBUG ((DEBUG_ERROR, "Fail to clear PK: %r\n", Status));
> +    return Status;
> +  }
> +
> +  // After PK clear, Setup Mode shall be enabled
> +  Status = GetSetupMode (&SetupMode);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot get SetupMode variable: %r\n",
> +      Status));
> +    return Status;
> +  }
> +
> +  if (SetupMode == USER_MODE) {
> +    DEBUG((DEBUG_INFO, "Skipped - USER_MODE\n"));
> +    return EFI_SUCCESS;
> +  }
> +
> +  Status = SetSecureBootMode (CUSTOM_SECURE_BOOT_MODE);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot set CUSTOM_SECURE_BOOT_MODE: %r\n",
> +      Status));
> +    return EFI_SUCCESS;
> +  }
> +
> +  // Enroll all the keys from default variables
> +  Status = EnrollDbFromDefault ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot enroll db: %r\n", Status));
> +    goto error;
> +  }
> +
> +  Status = EnrollDbxFromDefault ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot enroll dbx: %r\n", Status));
> +  }
> +
> +  Status = EnrollDbtFromDefault ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot enroll dbt: %r\n", Status));
> +  }
> +
> +  Status = EnrollKEKFromDefault ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot enroll KEK: %r\n", Status));
> +    goto cleardbs;
> +  }
> +
> +  Status = EnrollPKFromDefault ();
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot enroll PK: %r\n", Status));
> +    goto clearKEK;
> +  }
> +
> +  Status = SetSecureBootMode (STANDARD_SECURE_BOOT_MODE);
> +  if (EFI_ERROR (Status)) {
> +    DEBUG ((DEBUG_ERROR, "Cannot set CustomMode to STANDARD_SECURE_BOOT_MODE\n"
> +      "Please do it manually, otherwise system can be easily compromised\n"));
> +  }
> +
> +  return Status;
> +
> +clearKEK:
> +  DeleteKEK ();
> +
> +cleardbs:
> +  DeleteDbt ();
> +  DeleteDbx ();
> +  DeleteDb ();
> +
> +error:
> +  if (SetSecureBootMode (STANDARD_SECURE_BOOT_MODE) != EFI_SUCCESS) {
> +    DEBUG ((DEBUG_ERROR, "Cannot set mode to Secure: %r\n", Status));
> +  }
> +  return Status;
> +}
> +
>   /**
>     This function is called to provide results data to the driver.
>   
> @@ -4205,6 +4332,8 @@ SecureBootCallback (
>     SECUREBOOT_CONFIG_PRIVATE_DATA  *PrivateData;
>     BOOLEAN                         GetBrowserDataResult;
>     ENROLL_KEY_ERROR                EnrollKeyErrorCode;
> +  EFI_HII_POPUP_PROTOCOL          *HiiPopup;
> +  EFI_HII_POPUP_SELECTION         UserSelection;
>   
>     Status             = EFI_SUCCESS;
>     SecureBootEnable   = NULL;
> @@ -4755,6 +4884,31 @@ SecureBootCallback (
>           FreePool (SetupMode);
>         }
>         break;
> +    case KEY_SECURE_BOOT_RESET_TO_DEFAULT:
> +    {
> +      Status = gBS->LocateProtocol (&gEfiHiiPopupProtocolGuid, NULL, (VOID **) &HiiPopup);
> +      if (EFI_ERROR (Status)) {
> +        return Status;
> +      }
> +      Status = HiiPopup->CreatePopup (
> +                           HiiPopup,
> +                           EfiHiiPopupStyleInfo,
> +                           EfiHiiPopupTypeYesNo,
> +                           Private->HiiHandle,
> +                           STRING_TOKEN (STR_RESET_TO_DEFAULTS_POPUP),
> +                           &UserSelection
> +                           );
> +      if (UserSelection == EfiHiiPopupSelectionYes) {
> +        Status = KeyEnrollReset ();
> +      }
> +      //
> +      // Update secure boot strings after key reset
> +      //
> +      if (Status == EFI_SUCCESS) {
> +        Status = UpdateSecureBootString (Private);
> +        SecureBootExtractConfigFromVariable (Private, IfrNvData);
> +      }
> +    }
>       default:
>         break;
>       }
> diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigStrings.uni b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigStrings.uni
> index ac783453cc..0d01701de7 100644
> --- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigStrings.uni
> +++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigStrings.uni
> @@ -21,6 +21,10 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
>   #string STR_SECURE_BOOT_PROMPT             #language en-US "Attempt Secure Boot"
>   #string STR_SECURE_BOOT_HELP               #language en-US "Enable/Disable the Secure Boot feature after platform reset"
>   
> +#string STR_SECURE_RESET_TO_DEFAULTS_HELP  #language en-US "Enroll keys with data from default variables"
> +#string STR_SECURE_RESET_TO_DEFAULTS       #language en-US "Reset Secure Boot Keys"
> +#string STR_RESET_TO_DEFAULTS_POPUP        #language en-US "Secure Boot Keys & databases will be initialized from defaults.\n Are you sure?"
> +
>   #string STR_SECURE_BOOT_ENROLL_SIGNATURE   #language en-US "Enroll Signature"
>   #string STR_SECURE_BOOT_DELETE_SIGNATURE   #language en-US "Delete Signature"
>   #string STR_SECURE_BOOT_DELETE_LIST_FORM   #language en-US "Delete Signature List Form"
> 

Reviewed-by: Pete Batard <pete@akeo.ie>
Tested-by: Pete Batard <pete@akeo.ie> on Raspberry Pi 4