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bugfix in keyblob version changes #41

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Merged
merged 1 commit into from
Apr 8, 2022
Merged

bugfix in keyblob version changes #41

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51 changes: 30 additions & 21 deletions Applet/src/com/android/javacard/keymaster/KMKeymasterApplet.java
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Original file line number Diff line number Diff line change
Expand Up @@ -930,10 +930,7 @@ private boolean isKeyUpgradeRequired(short keyBlob, short appId, short appData,
// Check if the KeyBlob is compatible. If there is any change in the KeyBlob, the version
// Parameter in the KeyBlob should be updated to the next version.
short version = readKeyBlobVersion(keyBlob);
if (version > KEYBLOB_VERSION || version < 0) {
KMException.throwIt(KMError.INVALID_KEY_BLOB);
}
if (version == 0 || version < KEYBLOB_VERSION) {
if (version < KEYBLOB_VERSION) {
return true;
}
parseEncryptedKeyBlob(keyBlob, appId, appData, scratchPad, version);
Expand Down Expand Up @@ -976,6 +973,8 @@ private boolean isKeyUpgradeRequired(short keyBlob, short appId, short appData,
} else if (KMInteger.compare(tagValue, systemParam) == 1) {
KMException.throwIt(KMError.INVALID_ARGUMENT);
}
} else {
KMException.throwIt(KMError.UNKNOWN_ERROR);
}
index += 4;
}
Expand Down Expand Up @@ -1006,15 +1005,14 @@ private void processUpgradeKeyCmd(APDU apdu) {
// function itself, but if there is a difference in the KeyBlob version isKeyUpgradeRequired()
// does not parse the KeyBlob.
boolean isKeyUpgradeRequired = isKeyUpgradeRequired(keyBlob, appId, appData, scratchPad);
// Check if KeyBlob is already parsed in isKeyUpgradeRequired() function, If not parsed
// parse the KeyBlob.
if (data[KEY_BLOB] == KMType.INVALID_VALUE) {
// Parse existing key blob
parseEncryptedKeyBlob(keyBlob, data[APP_ID], data[APP_DATA], scratchPad,
readKeyBlobVersion(keyBlob));
}

if (isKeyUpgradeRequired) {
// Check if KeyBlob is already parsed in isKeyUpgradeRequired() function, If not parsed
// parse the KeyBlob.
if (data[KEY_BLOB] == KMType.INVALID_VALUE) {
// Parse existing key blob
parseEncryptedKeyBlob(keyBlob, data[APP_ID], data[APP_DATA], scratchPad,
readKeyBlobVersion(keyBlob));
}
// copy origin
data[ORIGIN] = KMEnumTag.getValue(KMType.ORIGIN, data[HW_PARAMETERS]);
makeKeyCharacteristics(scratchPad);
Expand Down Expand Up @@ -3801,8 +3799,12 @@ private short readKeyBlobVersion(short keyBlob) {
// If Version is not present. Then it is either an old KeyBlob or
// corrupted KeyBlob.
version = 0;
} else {
version = KMInteger.cast(version).getShort();
if (version > KEYBLOB_VERSION || version < 0) {
KMException.throwIt(KMError.INVALID_KEY_BLOB);
}
}
version = KMInteger.cast(version).getShort();
} catch(Exception e) {
KMException.throwIt(KMError.INVALID_KEY_BLOB);
}
Expand Down Expand Up @@ -3840,7 +3842,7 @@ private void readKeyBlobParams(short version, short parsedKeyBlob) {
}
}

private short decodeKeyBlob(short version, short keyBlob) {
private void decodeKeyBlob(short version, short keyBlob) {
// Decode KeyBlob and read the KeyBlob params based on the version.
short parsedBlob = decoder.decodeArray(createKeyBlobExp(version),
KMByteBlob.cast(keyBlob).getBuffer(),
Expand All @@ -3852,7 +3854,6 @@ private short decodeKeyBlob(short version, short keyBlob) {
KMException.throwIt(KMError.INVALID_KEY_BLOB);
}
readKeyBlobParams(version, parsedBlob);
return parsedBlob;
}

private void processDecryptSecret(short version, short appId, short appData, byte[] scratchPad) {
Expand All @@ -3870,21 +3871,19 @@ private void processDecryptSecret(short version, short appId, short appData, byt
KMArray.cast(data[KEY_BLOB]).add(keyBlobSecretOff, data[SECRET]);
}

private short parseEncryptedKeyBlob(short keyBlob, short appId, short appData,
private void parseEncryptedKeyBlob(short keyBlob, short appId, short appData,
byte[] scratchPad, short version) {
short parsedBlob = KMType.INVALID_VALUE;
// make root of trust blob
data[ROT] = readROT(scratchPad);
if (data[ROT] == KMType.INVALID_VALUE) {
KMException.throwIt(KMError.UNKNOWN_ERROR);
}
try {
parsedBlob = decodeKeyBlob(version, keyBlob);
decodeKeyBlob(version, keyBlob);
processDecryptSecret(version, appId, appData, scratchPad);
} catch (Exception e) {
KMException.throwIt(KMError.INVALID_KEY_BLOB);
}
return parsedBlob;
}

// Read RoT
Expand Down Expand Up @@ -3963,19 +3962,29 @@ private static void encryptSecret(byte[] scratchPad) {
data[SECRET] = KMByteBlob.instance(scratchPad, (short)0, len);
}

private static boolean isAsymetricKeyBlob(short hardwareParams) {
short alg = KMKeyParameters.findTag(KMType.ENUM_TAG, KMType.ALGORITHM, hardwareParams);
if(KMEnumTag.cast(alg).getValue() == KMType.RSA || KMEnumTag.cast(alg).getValue() == KMType.EC )
{
return true;
}
return false;
}

private static void makeAuthData(short version, byte[] scratchPad) {
// Auth Data includes HW_PARAMETERS, HIDDEN_PARAMETERS, VERSION and PUB_KEY.
// VERSION is included only for KeyBlobs having version >= 1.
// PUB_KEY is included for only ASYMMETRIC KeyBlobs.
short index = 0;
short arrayLen = 0;
Util.arrayFillNonAtomic(scratchPad, (short) 0, (short) 8, (byte) 0);
boolean isAsymKeyBlob = isAsymetricKeyBlob(data[HW_PARAMETERS]);
switch (version) {
case (short) 0:
// If the KeyBlob size is 5 then it contains an Asymmetric Key, otherwise
// it contains a Symmetric Key. For Asymmetric Keys include the PUB_KEY.
arrayLen = 2;
if (KMArray.cast(data[KEY_BLOB]).length() == ASYM_KEY_BLOB_SIZE_V0) {
if (isAsymKeyBlob) {
arrayLen = 3;
Util.setShort(scratchPad, (short) 4, data[PUB_KEY]);
}
Expand All @@ -3986,7 +3995,7 @@ private static void makeAuthData(short version, byte[] scratchPad) {
// If the KeyBlob size is 6 then it contains an Asymmetric Key, otherwise
// it contains a Symmetric Key. For Asymmetric Keys include the PUB_KEY.
arrayLen = 3;
if (KMArray.cast(data[KEY_BLOB]).length() == ASYM_KEY_BLOB_SIZE_V1) {
if (isAsymKeyBlob) {
arrayLen = 4;
Util.setShort(scratchPad, (short) 6, data[PUB_KEY]);
}
Expand Down