parse PIID from PCK SGX extensions

Signed-off-by: Markus Rudy <mr@edgeless.systems>

Author: burgerdev

pcs/pcs.go

@@ -31,6 +31,7 @@ const (
 	pckCertExtensionSize = 6
 	sgxExtensionMinSize  = 4
 	tcbExtensionSize     = 18
+	piidSize             = 16
 	ppidSize             = 16
 	cpuSvnSize           = 16
 	fmspcSize            = 6
@@ -77,6 +78,8 @@ var (
 	OidFMSPC = asn1.ObjectIdentifier([]int{1, 2, 840, 113741, 1, 13, 1, 4})
 	// OidSGXType is the x509v3 extension for PCK certificate's SGX Extensions SGX Type value.
 	OidSGXType = asn1.ObjectIdentifier([]int{1, 2, 840, 113741, 1, 13, 1, 5})
+	// OidPIID is the x509v3 extension for PCK certificate's SGX Extensions PIID value.
+	OidPIID = asn1.ObjectIdentifier([]int{1, 2, 840, 113741, 1, 13, 1, 6})
 
 	// ErrPckExtInvalid error returned when parsing PCK certificate's extension returns leftover bytes
 	ErrPckExtInvalid = errors.New("unexpected leftover bytes for PCK certificate's extension")
@@ -185,6 +188,7 @@ type PckExtensions struct {
 	PCEID   string
 	FMSPC   string
 	SGXType SGXType
+	PIID    string
 }
 
 // SGXType represents the type of the platform for which the PCK certificate was created
@@ -466,6 +470,12 @@ func extractSgxExtensions(extensions []asn1.RawValue) (*PckExtensions, error) {
 			}
 			pckExtension.SGXType = SGXType(sExtension.Value)
 		}
+		if sExtension.Type.Equal(OidPIID) {
+			pckExtension.PIID, err = extractAsn1OctetStringExtension("PIID", extensions[i], piidSize)
+			if err != nil {
+				return nil, err
+			}
+		}
 	}
 	return pckExtension, nil
 }

verify/verify_test.go

@@ -100,9 +100,11 @@ func TestPckCertificateExtensions(t *testing.T) {
 	}
 	pckExt := &pcs.PckExtensions{}
 	ppidBytes := []byte{8, 157, 223, 219, 156, 3, 89, 200, 42, 59, 199, 113, 146, 57, 87, 78}
+	piidBytes := []byte{0x8c, 0x31, 0x4d, 0x17, 0xd2, 0x5, 0xdf, 0xaf, 0xcb, 0xec, 0xbb, 0x0, 0xfc, 0x87, 0xef, 0xf7}
 	fmspcBytes := []byte{80, 128, 111, 0, 0, 0}
 	pceIDBytes := []byte{0, 0}
 	pckExt.PPID = hex.EncodeToString(ppidBytes)
+	pckExt.PIID = hex.EncodeToString(piidBytes)
 	pckExt.FMSPC = hex.EncodeToString(fmspcBytes)
 	pckExt.PCEID = hex.EncodeToString(pceIDBytes)
 	pckExt.SGXType = pcs.SGXTypeScalable