Fix malformed and spec violation of postibbdigest parsing

Signed-off-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>

Author: zaolin

pkg/intel/metadata/bg/bootpolicy/manifest_test.go

@@ -12,4 +12,5 @@ import (
 
 func TestReadWrite(t *testing.T) {
 	unittest.BGManifestReadWrite(t, &Manifest{}, "testdata/bpm.bin")
+	unittest.BGManifestReadWrite(t, &Manifest{}, "testdata/bpm2.bin")
 }

pkg/intel/metadata/bg/bootpolicy/se.go

@@ -34,7 +34,7 @@ type SE struct {
 	// PrettyString: DMA Protection 2 Limit Address
 	Reserved3 [8]byte `json:"seDMAProtLimit1"`
 
-	PostIBBHash bg.HashStructure `json:"sePostIBBHash"`
+	PostIBBHash bg.HashStructureFill `json:"sePostIBBHash"`
 
 	IBBEntryPoint uint32 `json:"seIBBEntry"`
 

pkg/intel/metadata/bg/bootpolicy/se_manifestcodegen.go

@@ -11,3 +11,42 @@ type HashStructure struct {
 	HashAlg    Algorithm `default:"0x10" json:"hsAlg"`
 	HashBuffer []byte    `json:"hsBuffer"`
 }
+
+type HashStructureFill struct {
+	HashAlg    Algorithm `default:"0x0b" json:"hsAlg"`
+	HashBuffer []byte    `countValue:"hashSize()" prettyValue:"hashSizePrint()" json:"hsBuffer"`
+}
+
+func (a Algorithm) size() uint16 {
+	switch a {
+	case AlgUnknown:
+		return 0
+	case AlgNull:
+		return 0
+	case AlgSHA1:
+		return 20
+	case AlgSHA256:
+		return 32
+	default:
+		return 0
+	}
+}
+
+func (h HashStructureFill) hashSize() uint16 {
+	const hashSizeFieldLen = 2
+	if h.HashAlg.IsNull() {
+		// Evil hack, more investigation needed
+		return AlgSHA256.size() + hashSizeFieldLen
+	} else {
+		return h.HashAlg.size() + hashSizeFieldLen
+	}
+}
+
+func (h HashStructureFill) hashSizePrint() interface{} {
+	if h.HashAlg.IsNull() {
+		// Evil hack, more investigation needed
+		return make([]byte, AlgSHA256.size())
+	} else {
+		return h.HashBuffer
+	}
+}

pkg/intel/metadata/bg/bootpolicy/testdata/bpm2.bin

@@ -40,7 +40,7 @@ func BGManifestReadWrite(t *testing.T, m bg.Manifest, testDataFilePath string) {
 	testData, err := os.ReadFile(testDataFilePath)
 	require.NoError(t, err)
 
-	nR, err := m.ReadFrom(bytes.NewReader(append(testData, []byte(`extra bytes`)...)))
+	nR, err := m.ReadFrom(bytes.NewReader(testData))
 	require.NoError(t, err)
 	require.Equal(t, int64(len(testData)), nR)
 	require.Equal(t, nR, int64(m.TotalSize()))