SecurityPkg: SecureBootVariableLib: Added newly supported interfaces

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3911

This change updated the interfaces provided by SecureBootVariableLib.

The new additions provided interfaces to enroll single authenticated
variable from input, a helper function to query secure boot status,
enroll all secure boot variables from UefiSecureBoot.h defined data
structures, a as well as a routine that deletes all secure boot related
variables.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Min Xu <min.m.xu@intel.com>

Signed-off-by: Kun Qin <kun.qin@microsoft.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Acked-by: Michael Kubacki <michael.kubacki@microsoft.com>

3 files changed, 437 insertions, 0 deletions

diff --git a/SecurityPkg/Include/Library/SecureBootVariableLib.h b/SecurityPkg/Include/Library/SecureBootVariableLib.h
index 24ff0df067..c486801c31 100644
--- a/SecurityPkg/Include/Library/SecureBootVariableLib.h
+++ b/SecurityPkg/Include/Library/SecureBootVariableLib.h
@@ -44,6 +44,19 @@ GetSetupMode (
   );

 

 /**

+  Helper function to quickly determine whether SecureBoot is enabled.

+

+  @retval     TRUE    SecureBoot is verifiably enabled.

+  @retval     FALSE   SecureBoot is either disabled or an error prevented checking.

+

+**/

+BOOLEAN

+EFIAPI

+IsSecureBootEnabled (

+  VOID

+  );

+

+/**

   Create a EFI Signature List with data supplied from input argument.

   The input certificates from KeyInfo parameter should be DER-encoded

   format.

@@ -161,4 +174,60 @@ DeletePlatformKey (
   VOID

   );

 

+/**

+  This function will delete the secure boot keys, thus

+  disabling secure boot.

+

+  @return EFI_SUCCESS or underlying failure code.

+**/

+EFI_STATUS

+EFIAPI

+DeleteSecureBootVariables (

+  VOID

+  );

+

+/**

+  A helper function to take in a variable payload, wrap it in the

+  proper authenticated variable structure, and install it in the

+  EFI variable space.

+

+  @param[in]  VariableName  The name of the key/database.

+  @param[in]  VendorGuid    The namespace (ie. vendor GUID) of the variable

+  @param[in]  DataSize      Size parameter for target secure boot variable.

+  @param[in]  Data          Pointer to signature list formatted secure boot variable content.

+

+  @retval EFI_SUCCESS              The enrollment for authenticated variable was successful.

+  @retval EFI_OUT_OF_RESOURCES     There are not enough memory resources to create time based payload.

+  @retval EFI_INVALID_PARAMETER    The parameter is invalid.

+  @retval Others                   Unexpected error happens.

+**/

+EFI_STATUS

+EFIAPI

+EnrollFromInput (

+  IN CHAR16    *VariableName,

+  IN EFI_GUID  *VendorGuid,

+  IN UINTN     DataSize,

+  IN VOID      *Data

+  );

+

+/**

+  Similar to DeleteSecureBootVariables, this function is used to unilaterally

+  force the state of related SB variables (db, dbx, dbt, KEK, PK, etc.) to be

+  the built-in, hardcoded default vars.

+

+  @param[in]  SecureBootPayload  Payload information for secure boot related keys.

+

+  @retval     EFI_SUCCESS               SecureBoot keys are now set to defaults.

+  @retval     EFI_ABORTED               SecureBoot keys are not empty. Please delete keys first

+                                        or follow standard methods of altering keys (ie. use the signing system).

+  @retval     EFI_SECURITY_VIOLATION    Failed to create the PK.

+  @retval     Others                    Something failed in one of the subfunctions.

+

+**/

+EFI_STATUS

+EFIAPI

+SetSecureBootVariablesToDefault (

+  IN  CONST SECURE_BOOT_PAYLOAD_INFO  *SecureBootPayload

+  );

+

 #endif

diff --git a/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.c b/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.c
index f56f0322e9..abca249c65 100644
--- a/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.c
+++ b/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.c
@@ -21,6 +21,7 @@
 #include <Library/MemoryAllocationLib.h>

 #include <Library/UefiRuntimeServicesTableLib.h>

 #include <Library/SecureBootVariableLib.h>

+#include <Library/PlatformPKProtectionLib.h>

 

 // This time can be used when deleting variables, as it should be greater than any variable time.

 EFI_TIME  mMaxTimestamp = {

@@ -37,6 +38,24 @@ EFI_TIME  mMaxTimestamp = {
   0x00

 };

 

+//

+// This epoch time is the date that is used when creating SecureBoot default variables.

+// NOTE: This is a placeholder date that doesn't correspond to anything else.

+//

+EFI_TIME  mDefaultPayloadTimestamp = {

+  1970, // Year (1970)

+  1,    // Month (Jan)

+  1,    // Day (1)

+  0,    // Hour

+  0,    // Minute

+  0,    // Second

+  0,    // Pad1

+  0,    // Nanosecond

+  0,    // Timezone (Dummy value)

+  0,    // Daylight (Dummy value)

+  0     // Pad2

+};

+

 /** Creates EFI Signature List structure.

 

   @param[in]      Data     A pointer to signature data.

@@ -414,6 +433,44 @@ GetSetupMode (
 }

 

 /**

+  Helper function to quickly determine whether SecureBoot is enabled.

+

+  @retval     TRUE    SecureBoot is verifiably enabled.

+  @retval     FALSE   SecureBoot is either disabled or an error prevented checking.

+

+**/

+BOOLEAN

+EFIAPI

+IsSecureBootEnabled (

+  VOID

+  )

+{

+  EFI_STATUS  Status;

+  UINT8       *SecureBoot;

+

+  SecureBoot = NULL;

+

+  Status = GetEfiGlobalVariable2 (EFI_SECURE_BOOT_MODE_NAME, (VOID **)&SecureBoot, NULL);

+  //

+  // Skip verification if SecureBoot variable doesn't exist.

+  //

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_ERROR, "Cannot check SecureBoot variable %r \n ", Status));

+    return FALSE;

+  }

+

+  //

+  // Skip verification if SecureBoot is disabled but not AuditMode

+  //

+  if (*SecureBoot == SECURE_BOOT_MODE_DISABLE) {

+    FreePool (SecureBoot);

+    return FALSE;

+  } else {

+    return TRUE;

+  }

+}

+

+/**

   Clears the content of the 'db' variable.

 

   @retval EFI_OUT_OF_RESOURCES      If memory allocation for EFI_VARIABLE_AUTHENTICATION_2 fails

@@ -531,3 +588,311 @@ DeletePlatformKey (
              );

   return Status;

 }

+

+/**

+  This function will delete the secure boot keys, thus

+  disabling secure boot.

+

+  @return EFI_SUCCESS or underlying failure code.

+**/

+EFI_STATUS

+EFIAPI

+DeleteSecureBootVariables (

+  VOID

+  )

+{

+  EFI_STATUS  Status, TempStatus;

+

+  DEBUG ((DEBUG_INFO, "%a - Attempting to delete the Secure Boot variables.\n", __FUNCTION__));

+

+  //

+  // Step 1: Notify that a PK update is coming shortly...

+  Status = DisablePKProtection ();

+  if (EFI_ERROR (Status)) {

+    DEBUG ((DEBUG_ERROR, "%a - Failed to signal PK update start! %r\n", __FUNCTION__, Status));

+    // Classify this as a PK deletion error.

+    Status = EFI_ABORTED;

+  }

+

+  //

+  // Step 2: Attempt to delete the PK.

+  // Let's try to nuke the PK, why not...

+  if (!EFI_ERROR (Status)) {

+    Status = DeletePlatformKey ();

+    DEBUG ((DEBUG_INFO, "%a - PK Delete = %r\n", __FUNCTION__, Status));

+    // If the PK is not found, then our work here is done.

+    if (Status == EFI_NOT_FOUND) {

+      Status = EFI_SUCCESS;

+    }

+    // If any other error occurred, let's inform the caller that the PK delete in particular failed.

+    else if (EFI_ERROR (Status)) {

+      Status = EFI_ABORTED;

+    }

+  }

+

+  //

+  // Step 3: Attempt to delete remaining keys/databases...

+  // Now that the PK is deleted (assuming Status == EFI_SUCCESS) the system is in SETUP_MODE.

+  // Arguably we could leave these variables in place and let them be deleted by whoever wants to

+  // update all the SecureBoot variables. However, for cleanliness sake, let's try to

+  // get rid of them here.

+  if (!EFI_ERROR (Status)) {

+    //

+    // If any of THESE steps have an error, report the error but attempt to delete all keys.

+    // Using TempStatus will prevent an error from being trampled by an EFI_SUCCESS.

+    // Overwrite Status ONLY if TempStatus is an error.

+    //

+    // If the error is EFI_NOT_FOUND, we can safely ignore it since we were trying to delete

+    // the variables anyway.

+    //

+    TempStatus = DeleteKEK ();

+    DEBUG ((DEBUG_INFO, "%a - KEK Delete = %r\n", __FUNCTION__, TempStatus));

+    if (EFI_ERROR (TempStatus) && (TempStatus != EFI_NOT_FOUND)) {

+      Status = EFI_ACCESS_DENIED;

+    }

+

+    TempStatus = DeleteDb ();

+    DEBUG ((DEBUG_INFO, "%a - db Delete = %r\n", __FUNCTION__, TempStatus));

+    if (EFI_ERROR (TempStatus) && (TempStatus != EFI_NOT_FOUND)) {

+      Status = EFI_ACCESS_DENIED;

+    }

+

+    TempStatus = DeleteDbx ();

+    DEBUG ((DEBUG_INFO, "%a - dbx Delete = %r\n", __FUNCTION__, TempStatus));

+    if (EFI_ERROR (TempStatus) && (TempStatus != EFI_NOT_FOUND)) {

+      Status = EFI_ACCESS_DENIED;

+    }

+

+    TempStatus = DeleteDbt ();

+    DEBUG ((DEBUG_INFO, "%a - dbt Delete = %r\n", __FUNCTION__, TempStatus));

+    if (EFI_ERROR (TempStatus) && (TempStatus != EFI_NOT_FOUND)) {

+      Status = EFI_ACCESS_DENIED;

+    }

+  }

+

+  return Status;

+}// DeleteSecureBootVariables()

+

+/**

+  A helper function to take in a variable payload, wrap it in the

+  proper authenticated variable structure, and install it in the

+  EFI variable space.

+

+  @param[in]  VariableName  The name of the key/database.

+  @param[in]  VendorGuid    The namespace (ie. vendor GUID) of the variable

+  @param[in]  DataSize      Size parameter for target secure boot variable.

+  @param[in]  Data          Pointer to signature list formatted secure boot variable content.

+

+  @retval EFI_SUCCESS              The enrollment for authenticated variable was successful.

+  @retval EFI_OUT_OF_RESOURCES     There are not enough memory resources to create time based payload.

+  @retval EFI_INVALID_PARAMETER    The parameter is invalid.

+  @retval Others                   Unexpected error happens.

+**/

+EFI_STATUS

+EFIAPI

+EnrollFromInput (

+  IN CHAR16    *VariableName,

+  IN EFI_GUID  *VendorGuid,

+  IN UINTN     DataSize,

+  IN VOID      *Data

+  )

+{

+  VOID        *Payload;

+  UINTN       PayloadSize;

+  EFI_STATUS  Status;

+

+  Payload = NULL;

+

+  if ((VariableName == NULL) || (VendorGuid == 0)) {

+    DEBUG ((DEBUG_ERROR, "Input vendor variable invalid: %p and %p\n", VariableName, VendorGuid));

+    Status = EFI_INVALID_PARAMETER;

+    goto Exit;

+  }

+

+  if ((Data == NULL) || (DataSize == 0)) {

+    // You might as well just use DeleteVariable...

+    DEBUG ((DEBUG_ERROR, "Input argument invalid: %p: %x\n", Data, DataSize));

+    Status = EFI_INVALID_PARAMETER;

+    goto Exit;

+  }

+

+  // Bring in the noise...

+  PayloadSize = DataSize;

+  Payload     = AllocateZeroPool (DataSize);

+  // Bring in the funk...

+  if (Payload == NULL) {

+    return EFI_OUT_OF_RESOURCES;

+  } else {

+    CopyMem (Payload, Data, DataSize);

+  }

+

+  Status = CreateTimeBasedPayload (&PayloadSize, (UINT8 **)&Payload, &mDefaultPayloadTimestamp);

+  if (EFI_ERROR (Status) || (Payload == NULL)) {

+    DEBUG ((DEBUG_ERROR, "Fail to create time-based data payload: %r\n", Status));

+    Payload = NULL;

+    Status  = EFI_OUT_OF_RESOURCES;

+    goto Exit;

+  }

+

+  //

+  // Allocate memory for auth variable

+  //

+  Status = gRT->SetVariable (

+                  VariableName,

+                  VendorGuid,

+                  (EFI_VARIABLE_NON_VOLATILE |

+                   EFI_VARIABLE_BOOTSERVICE_ACCESS |

+                   EFI_VARIABLE_RUNTIME_ACCESS |

+                   EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS),

+                  PayloadSize,

+                  Payload

+                  );

+

+  if (EFI_ERROR (Status)) {

+    DEBUG ((

+      DEBUG_ERROR,

+      "error: %a (\"%s\", %g): %r\n",

+      __FUNCTION__,

+      VariableName,

+      VendorGuid,

+      Status

+      ));

+  }

+

+Exit:

+  //

+  // Always Put Away Your Toys

+  // Payload will be reassigned by CreateTimeBasedPayload()...

+  if (Payload != NULL) {

+    FreePool (Payload);

+    Payload = NULL;

+  }

+

+  return Status;

+}

+

+/**

+  Similar to DeleteSecureBootVariables, this function is used to unilaterally

+  force the state of related SB variables (db, dbx, dbt, KEK, PK, etc.) to be

+  the built-in, hardcoded default vars.

+

+  @param[in]  SecureBootPayload  Payload information for secure boot related keys.

+

+  @retval     EFI_SUCCESS               SecureBoot keys are now set to defaults.

+  @retval     EFI_ABORTED               SecureBoot keys are not empty. Please delete keys first

+                                        or follow standard methods of altering keys (ie. use the signing system).

+  @retval     EFI_SECURITY_VIOLATION    Failed to create the PK.

+  @retval     Others                    Something failed in one of the subfunctions.

+

+**/

+EFI_STATUS

+EFIAPI

+SetSecureBootVariablesToDefault (

+  IN  CONST SECURE_BOOT_PAYLOAD_INFO  *SecureBootPayload

+  )

+{

+  EFI_STATUS  Status;

+  UINT8       *Data;

+  UINTN       DataSize;

+

+  DEBUG ((DEBUG_INFO, "%a() Entry\n", __FUNCTION__));

+

+  if (SecureBootPayload == NULL) {

+    DEBUG ((DEBUG_ERROR, "%a - Invalid SecureBoot payload is supplied!\n", __FUNCTION__));

+    return EFI_INVALID_PARAMETER;

+  }

+

+  //

+  // Right off the bat, if SecureBoot is currently enabled, bail.

+  if (IsSecureBootEnabled ()) {

+    DEBUG ((DEBUG_ERROR, "%a - Cannot set default keys while SecureBoot is enabled!\n", __FUNCTION__));

+    return EFI_ABORTED;

+  }

+

+  DEBUG ((DEBUG_INFO, "%a - Setting up key %s!\n", __FUNCTION__, SecureBootPayload->SecureBootKeyName));

+

+  //

+  // Start running down the list, creating variables in our wake.

+  // dbx is a good place to start.

+  Data     = (UINT8 *)SecureBootPayload->DbxPtr;

+  DataSize = SecureBootPayload->DbxSize;

+  Status   = EnrollFromInput (

+               EFI_IMAGE_SECURITY_DATABASE1,

+               &gEfiImageSecurityDatabaseGuid,

+               DataSize,

+               Data

+               );

+

+  // If that went well, try the db (make sure to pick the right one!).

+  if (!EFI_ERROR (Status)) {

+    Data     = (UINT8 *)SecureBootPayload->DbPtr;

+    DataSize = SecureBootPayload->DbSize;

+    Status   = EnrollFromInput (

+                 EFI_IMAGE_SECURITY_DATABASE,

+                 &gEfiImageSecurityDatabaseGuid,

+                 DataSize,

+                 Data

+                 );

+    if (EFI_ERROR (Status)) {

+      DEBUG ((DEBUG_ERROR, "%a - Failed to enroll DB %r!\n", __FUNCTION__, Status));

+    }

+  } else {

+    DEBUG ((DEBUG_ERROR, "%a - Failed to enroll DBX %r!\n", __FUNCTION__, Status));

+  }

+

+  // Keep it going. Keep it going. dbt if supplied...

+  if (!EFI_ERROR (Status) && (SecureBootPayload->DbtPtr != NULL)) {

+    Data     = (UINT8 *)SecureBootPayload->DbtPtr;

+    DataSize = SecureBootPayload->DbtSize;

+    Status   = EnrollFromInput (

+                 EFI_IMAGE_SECURITY_DATABASE2,

+                 &gEfiImageSecurityDatabaseGuid,

+                 DataSize,

+                 Data

+                 );

+    if (EFI_ERROR (Status)) {

+      DEBUG ((DEBUG_ERROR, "%a - Failed to enroll DBT %r!\n", __FUNCTION__, Status));

+    }

+  }

+

+  // Keep it going. Keep it going. KEK...

+  if (!EFI_ERROR (Status)) {

+    Data     = (UINT8 *)SecureBootPayload->KekPtr;

+    DataSize = SecureBootPayload->KekSize;

+    Status   = EnrollFromInput (

+                 EFI_KEY_EXCHANGE_KEY_NAME,

+                 &gEfiGlobalVariableGuid,

+                 DataSize,

+                 Data

+                 );

+    if (EFI_ERROR (Status)) {

+      DEBUG ((DEBUG_ERROR, "%a - Failed to enroll KEK %r!\n", __FUNCTION__, Status));

+    }

+  }

+

+  //

+  // Finally! The Big Daddy of them all.

+  // The PK!

+  //

+  if (!EFI_ERROR (Status)) {

+    //

+    // Finally, install the key.

+    Data     = (UINT8 *)SecureBootPayload->PkPtr;

+    DataSize = SecureBootPayload->PkSize;

+    Status   = EnrollFromInput (

+                 EFI_PLATFORM_KEY_NAME,

+                 &gEfiGlobalVariableGuid,

+                 DataSize,

+                 Data

+                 );

+

+    //

+    // Report PK creation errors.

+    if (EFI_ERROR (Status)) {

+      DEBUG ((DEBUG_ERROR, "%a - Failed to update the PK! - %r\n", __FUNCTION__, Status));

+      Status = EFI_SECURITY_VIOLATION;

+    }

+  }

+

+  return Status;

+}

diff --git a/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.inf b/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.inf
index 3d4b77cfb0..eabe9db6c9 100644
--- a/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.inf
+++ b/SecurityPkg/Library/SecureBootVariableLib/SecureBootVariableLib.inf
@@ -38,6 +38,9 @@
   BaseMemoryLib

   DebugLib

   MemoryAllocationLib

+  PlatformPKProtectionLib

+  UefiLib

+  UefiRuntimeServicesTableLib

 

 [Guids]

   ## CONSUMES            ## Variable:L"SetupMode"