FmpDevicePkg: Add DECLARE_LENGTH opcode of dependency expression

To avoid messy parsing of the Depex section of a Capsule, it would
be a lot easier for everyone involved if we preceded the Capsule Depex
Section with a length declaration. It provides simple bounds checking
to avoid having to parse the op-codes, but in the case of a malformed
depex being parsed, avoid other issues which can be messy.

REF: UEFI spec 2.10 Table 23.4

Signed-off-by: Yi Li <yi1.li@intel.com>

Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Wei6 Xu <wei6.xu@intel.com>
Reviewed-by: Wei6 Xu <wei6.xu@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

1 files changed, 35 insertions, 0 deletions

diff --git a/FmpDevicePkg/Library/FmpDependencyLib/FmpDependencyLib.c b/FmpDevicePkg/Library/FmpDependencyLib/FmpDependencyLib.c
index 76a1ee3..50662e7 100644
--- a/FmpDevicePkg/Library/FmpDependencyLib/FmpDependencyLib.c
+++ b/FmpDevicePkg/Library/FmpDependencyLib/FmpDependencyLib.c
@@ -234,6 +234,7 @@ EvaluateDependency (
   GUID           ImageTypeId;

   UINT32         Version;

   UINT32         LocalLastAttemptStatus;

+  UINT32         DeclaredLength;

 

   LocalLastAttemptStatus = LAST_ATTEMPT_STATUS_SUCCESS;

 

@@ -489,6 +490,37 @@ EvaluateDependency (
         }

 

         return Element1.Value.Boolean;

+      case EFI_FMP_DEP_DECLARE_LENGTH:

+        if (Iterator + sizeof (UINT32) >= (UINT8 *)Dependencies->Dependencies + DependenciesSize ) {

+          DEBUG ((DEBUG_ERROR, "EvaluateDependency: DECLARE_LENGTH extends beyond end of dependency expression!\n"));

+          LocalLastAttemptStatus = LAST_ATTEMPT_STATUS_DEPENDENCY_LIB_ERROR_DECLARE_LENGTH_BEYOND_DEPEX;

+          goto Error;

+        }

+

+        //

+        // This opcode must be the first one in a dependency expression.

+        //

+        if (Iterator != Dependencies->Dependencies) {

+          DEBUG ((DEBUG_ERROR, "EvaluateDependency: DECLARE_LENGTH is not the first opcode!\n"));

+          LocalLastAttemptStatus = LAST_ATTEMPT_STATUS_DEPENDENCY_LIB_ERROR_DECLARE_LENGTH_NOT_FIRST_OPCODE;

+          goto Error;

+        }

+

+        DeclaredLength = *(UINT32 *)(Iterator + 1);

+        if (DeclaredLength != DependenciesSize) {

+          DEBUG ((DEBUG_ERROR, "EvaluateDependency: DECLARE_LENGTH is not equal to length of dependency expression!\n"));

+          LocalLastAttemptStatus = LAST_ATTEMPT_STATUS_DEPENDENCY_LIB_ERROR_DECLARE_LENGTH_INCORRECT;

+          goto Error;

+        }

+

+        Status = Push (DeclaredLength, VersionType);

+        if (EFI_ERROR (Status)) {

+          LocalLastAttemptStatus = LAST_ATTEMPT_STATUS_DEPENDENCY_LIB_ERROR_PUSH_FAILURE;

+          goto Error;

+        }

+

+        Iterator = Iterator + sizeof (UINT32);

+        break;

       default:

         DEBUG ((DEBUG_ERROR, "EvaluateDependency: Unknown Opcode - %02x!\n", *Iterator));

         LocalLastAttemptStatus = LAST_ATTEMPT_STATUS_DEPENDENCY_LIB_ERROR_UNKNOWN_OPCODE;

@@ -574,6 +606,9 @@ ValidateDependency (
         }

 

         return TRUE;

+      case EFI_FMP_DEP_DECLARE_LENGTH:

+        Depex += sizeof (UINT32) + 1;

+        break;

       default:

         return FALSE;

     }