| /* |
| * Copyright(C) 2021 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.javacard.keymaster; |
| |
| import javacard.framework.ISO7816; |
| import javacard.framework.ISOException; |
| import javacard.framework.Util; |
| |
| /** |
| * KMCoseKey represents COSE_Key section from the Cose standard |
| * https://datatracker.ietf.org/doc/html/rfc8152#section-7 The supported key types are KMNInteger, |
| * KMInteger and the supported value types are KMInteger, KMNInteger, KMByteBlob, KMSimpleValue. It |
| * corresponds to a CBOR Map type. struct{byte TAG_TYPE; short length; short arrayPtr } where |
| * arrayPtr is a pointer to array with any KMTag subtype instances. Note that construction of the |
| * key_ops label is not needed to be supported. In the KeyMint3.0 specifications: The CoseKey inside |
| * MacedPublicKeys and DiceCertChain does not have key_ops label. |
| */ |
| public class KMCoseKey extends KMCoseMap { |
| |
| private static KMCoseKey prototype; |
| |
| private KMCoseKey() {} |
| |
| private static KMCoseKey proto(short ptr) { |
| if (prototype == null) { |
| prototype = new KMCoseKey(); |
| } |
| instanceTable[KM_COSE_KEY_OFFSET] = ptr; |
| return prototype; |
| } |
| |
| public static short exp() { |
| short arrPtr = KMArray.instance((short) 4); |
| KMArray arr = KMArray.cast(arrPtr); |
| arr.add((short) 0, KMCosePairIntegerTag.exp()); |
| arr.add((short) 1, KMCosePairNegIntegerTag.exp()); |
| arr.add((short) 2, KMCosePairByteBlobTag.exp()); |
| arr.add((short) 3, KMCosePairSimpleValueTag.exp()); |
| return KMCoseKey.instance(arrPtr); |
| } |
| |
| public static short instance(short vals) { |
| short ptr = KMType.instance(COSE_KEY_TYPE, (short) 2); |
| Util.setShort(heap, (short) (ptr + TLV_HEADER_SIZE), vals); |
| return ptr; |
| } |
| |
| public static KMCoseKey cast(short ptr) { |
| if (heap[ptr] != COSE_KEY_TYPE) { |
| ISOException.throwIt(ISO7816.SW_CONDITIONS_NOT_SATISFIED); |
| } |
| short arrPtr = Util.getShort(heap, (short) (ptr + TLV_HEADER_SIZE)); |
| if (heap[arrPtr] != ARRAY_TYPE) { |
| ISOException.throwIt(ISO7816.SW_CONDITIONS_NOT_SATISFIED); |
| } |
| return proto(ptr); |
| } |
| |
| @Override |
| public short getVals() { |
| return Util.getShort(heap, (short) (instanceTable[KM_COSE_KEY_OFFSET] + TLV_HEADER_SIZE)); |
| } |
| |
| @Override |
| public short length() { |
| short arrPtr = getVals(); |
| return KMArray.cast(arrPtr).length(); |
| } |
| |
| private short getValueType(short key, short significantKey) { |
| short arr = getVals(); |
| short length = length(); |
| short keyPtr; |
| short valPtr = 0; |
| short index = 0; |
| short tagType; |
| boolean found = false; |
| while (index < length) { |
| tagType = KMCosePairTagType.getTagValueType(KMArray.cast(arr).get(index)); |
| switch (tagType) { |
| case KMType.COSE_PAIR_BYTE_BLOB_TAG_TYPE: |
| keyPtr = KMCosePairByteBlobTag.cast(KMArray.cast(arr).get(index)).getKeyPtr(); |
| if (key == (byte) KMCosePairTagType.getKeyValueShort(keyPtr)) { |
| valPtr = KMCosePairByteBlobTag.cast(KMArray.cast(arr).get(index)).getValuePtr(); |
| found = true; |
| } |
| break; |
| case KMType.COSE_PAIR_INT_TAG_TYPE: |
| keyPtr = KMCosePairIntegerTag.cast(KMArray.cast(arr).get(index)).getKeyPtr(); |
| if (key == (byte) KMCosePairTagType.getKeyValueShort(keyPtr)) { |
| valPtr = KMCosePairIntegerTag.cast(KMArray.cast(arr).get(index)).getValuePtr(); |
| found = true; |
| } |
| break; |
| case KMType.COSE_PAIR_NEG_INT_TAG_TYPE: |
| keyPtr = KMCosePairNegIntegerTag.cast(KMArray.cast(arr).get(index)).getKeyPtr(); |
| if (key == (byte) KMCosePairTagType.getKeyValueShort(keyPtr)) { |
| valPtr = KMCosePairNegIntegerTag.cast(KMArray.cast(arr).get(index)).getValuePtr(); |
| found = true; |
| } |
| break; |
| case KMType.COSE_PAIR_SIMPLE_VALUE_TAG_TYPE: |
| keyPtr = KMCosePairSimpleValueTag.cast(KMArray.cast(arr).get(index)).getKeyPtr(); |
| if (key == KMCosePairTagType.getKeyValueShort(keyPtr) |
| && significantKey == KMCosePairTagType.getKeyValueSignificantShort(keyPtr)) { |
| valPtr = KMCosePairSimpleValueTag.cast(KMArray.cast(arr).get(index)).getValuePtr(); |
| found = true; |
| } |
| break; |
| default: |
| break; |
| } |
| if (found) { |
| break; |
| } |
| index++; |
| } |
| return valPtr; |
| } |
| |
| public short getEcdsa256PublicKey(byte[] pubKey, short pubKeyOff) { |
| short baseOffset = pubKeyOff; |
| pubKey[pubKeyOff] = (byte) 0x04; // uncompressed. |
| pubKeyOff++; |
| short ptr = getValueType(KMCose.COSE_KEY_PUBKEY_X, KMType.INVALID_VALUE); |
| Util.arrayCopy( |
| KMByteBlob.cast(ptr).getBuffer(), |
| KMByteBlob.cast(ptr).getStartOff(), |
| pubKey, |
| pubKeyOff, |
| KMByteBlob.cast(ptr).length()); |
| pubKeyOff += KMByteBlob.cast(ptr).length(); |
| ptr = getValueType(KMCose.COSE_KEY_PUBKEY_Y, KMType.INVALID_VALUE); |
| Util.arrayCopy( |
| KMByteBlob.cast(ptr).getBuffer(), |
| KMByteBlob.cast(ptr).getStartOff(), |
| pubKey, |
| pubKeyOff, |
| KMByteBlob.cast(ptr).length()); |
| pubKeyOff += KMByteBlob.cast(ptr).length(); |
| return (short) (pubKeyOff - baseOffset); |
| } |
| |
| public short getPrivateKey(byte[] priv, short privOff) { |
| short ptr = getValueType(KMCose.COSE_KEY_PRIV_KEY, KMType.INVALID_VALUE); |
| Util.arrayCopy( |
| KMByteBlob.cast(ptr).getBuffer(), |
| KMByteBlob.cast(ptr).getStartOff(), |
| priv, |
| privOff, |
| KMByteBlob.cast(ptr).length()); |
| return KMByteBlob.cast(ptr).length(); |
| } |
| |
| public boolean isTestKey() { |
| short ptr = |
| getValueType( |
| Util.getShort(KMCose.COSE_TEST_KEY, (short) 2), // LSB |
| Util.getShort(KMCose.COSE_TEST_KEY, (short) 0) // MSB (Significant) |
| ); |
| boolean isTestKey = false; |
| if (ptr != 0) { |
| isTestKey = (KMSimpleValue.cast(ptr).getValue() == KMSimpleValue.NULL); |
| } |
| return isTestKey; |
| } |
| |
| /** |
| * Verifies the KMCoseKey values against the input values. Note that construction of the key_ops |
| * label is not needed to be supported. In the KeyMint3.0 specifications: The CoseKey inside |
| * MacedPublicKeys and DiceCertChain does not have key_ops label. |
| * |
| * @param keyType value of the key type |
| * @param keyIdPtr instance of KMByteBlob containing the key id. |
| * @param keyAlg value of the algorithm. |
| * @param keyOps value of the key operations. |
| * @param curve value of the curve. |
| * @return true if valid, otherwise false. |
| */ |
| public boolean isDataValid( |
| short[] buff, short keyType, short keyIdPtr, short keyAlg, short curve) { |
| short buffLen = 8; |
| buff[0] = KMCose.COSE_KEY_KEY_TYPE; |
| buff[1] = keyType; |
| buff[2] = KMCose.COSE_KEY_KEY_ID; |
| buff[3] = keyIdPtr; |
| buff[4] = KMCose.COSE_KEY_ALGORITHM; |
| buff[5] = keyAlg; |
| buff[6] = KMCose.COSE_KEY_CURVE; |
| buff[7] = curve; |
| boolean valid = false; |
| short ptr; |
| short tagIndex = 0; |
| short value; |
| while (tagIndex < buffLen) { |
| value = buff[(short) (tagIndex + 1)]; |
| if (value != KMType.INVALID_VALUE) { |
| valid = false; |
| ptr = getValueType(buff[tagIndex], KMType.INVALID_VALUE); |
| switch (KMType.getType(ptr)) { |
| case KMType.BYTE_BLOB_TYPE: |
| if ((KMByteBlob.cast(value).length() == KMByteBlob.cast(ptr).length()) |
| && (0 |
| == Util.arrayCompare( |
| KMByteBlob.cast(value).getBuffer(), |
| KMByteBlob.cast(value).getStartOff(), |
| KMByteBlob.cast(ptr).getBuffer(), |
| KMByteBlob.cast(ptr).getStartOff(), |
| KMByteBlob.cast(ptr).length()))) { |
| valid = true; |
| } |
| break; |
| case KMType.INTEGER_TYPE: |
| if (value == KMInteger.cast(ptr).getShort()) { |
| valid = true; |
| } |
| break; |
| case KMType.NEG_INTEGER_TYPE: |
| if ((byte) value == (byte) KMNInteger.cast(ptr).getShort()) { |
| valid = true; |
| } |
| break; |
| } |
| if (!valid) { |
| break; |
| } |
| } |
| tagIndex += 2; |
| } |
| return valid; |
| } |
| |
| @Override |
| public void canonicalize() { |
| KMCoseMap.canonicalize(getVals()); |
| } |
| } |
