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fix yubikey curve OID bug by reworking ASN1 parsing

master
Dominik Schürmann 2021-02-23 18:10:15 +01:00
parent 38f50c2af6
commit 2a0625e615
5 changed files with 127 additions and 50 deletions
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141
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/ECKeyFormat.java
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@ -17,63 +17,151 @@
package org.sufficientlysecure.keychain.securitytoken;
import androidx.annotation.Nullable;
import com.google.auto.value.AutoValue;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.nist.NISTNamedCurves;
import org.bouncycastle.asn1.x9.ECNamedCurveTable;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
import org.bouncycastle.bcpg.sig.KeyFlags;
import org.bouncycastle.math.ec.ECCurve;
import org.bouncycastle.util.Arrays;
import org.sufficientlysecure.keychain.service.SaveKeyringParcel;
import org.sufficientlysecure.keychain.service.SaveKeyringParcel.SubkeyAdd;
import java.io.IOException;
import timber.log.Timber;
// 4.3.3.6 Algorithm Attributes
public class ECKeyFormat extends KeyFormat {
@AutoValue
public abstract class ECKeyFormat extends KeyFormat {
private final ECAlgorithmFormat mECAlgorithmFormat;
private final ASN1ObjectIdentifier mECCurveOID;
public abstract byte[] oidField();
public ECKeyFormat(final ASN1ObjectIdentifier ecCurveOid,
final ECAlgorithmFormat ecAlgorithmFormat) {
@Nullable // TODO
public abstract ECAlgorithmFormat ecAlgorithmFormat();
private static final byte ATTRS_IMPORT_FORMAT_WITH_PUBKEY = (byte) 0xff;
ECKeyFormat() {
super(KeyFormatType.ECKeyFormatType);
mECAlgorithmFormat = ecAlgorithmFormat;
mECCurveOID = ecCurveOid;
}
public ECKeyFormat.ECAlgorithmFormat getAlgorithmFormat() {
return mECAlgorithmFormat;
public static KeyFormat getInstance(byte[] oidField, ECAlgorithmFormat from) {
return new AutoValue_ECKeyFormat(oidField, from);
}
public ASN1ObjectIdentifier getCurveOID() {
return mECCurveOID;
public static ECKeyFormat getInstance(ASN1ObjectIdentifier oidAsn1, ECAlgorithmFormat from) {
byte[] oidField = asn1ToOidField(oidAsn1);
return new AutoValue_ECKeyFormat(oidField, from);
}
public static KeyFormat getInstanceFromBytes(byte[] bytes) {
if (bytes.length < 2) {
throw new IllegalArgumentException("Bad length for EC attributes");
}
int len = bytes.length - 1;
if (bytes[bytes.length - 1] == ATTRS_IMPORT_FORMAT_WITH_PUBKEY) {
len -= 1;
}
final byte[] oidField = new byte[len];
System.arraycopy(bytes, 1, oidField, 0, len);
return getInstance(oidField, ECKeyFormat.ECAlgorithmFormat.from(bytes[0], bytes[bytes.length - 1]));
}
public byte[] toBytes(KeyType slot) {
byte[] attrs = new byte[1 + oidField().length + 1];
attrs[0] = ecAlgorithmFormat().getAlgorithmId();
System.arraycopy(oidField(), 0, attrs, 1, oidField().length);
attrs[attrs.length - 1] = ATTRS_IMPORT_FORMAT_WITH_PUBKEY;
return attrs;
}
public ASN1ObjectIdentifier asn1ParseOid() {
ASN1ObjectIdentifier asn1CurveOid = oidFieldToOidAsn1(oidField());
String curveName = ECNamedCurveTable.getName(asn1CurveOid);
if (curveName == null) {
Timber.w("Unknown curve OID: %s. Could be YubiKey firmware bug < 5.2.8. Trying again with last byte removed.", asn1CurveOid.getId());
// https://bugs.chromium.org/p/chromium/issues/detail?id=1120933#c10
// The OpenPGP applet of a Yubikey with firmware version below 5.2.8 appends
// a potentially arbitrary byte to the intended byte representation of an ECC
// curve OID. This case is handled by retrying the decoding with the last
// byte stripped if the resulting OID does not label a known curve.
byte[] oidRemoveLastByte = Arrays.copyOf(oidField(), oidField().length - 1);
ASN1ObjectIdentifier asn1CurveOidYubikey = oidFieldToOidAsn1(oidRemoveLastByte);
curveName = ECNamedCurveTable.getName(asn1CurveOidYubikey);
if (curveName != null) {
Timber.w("Detected curve OID: %s", asn1CurveOidYubikey.getId());
return asn1CurveOidYubikey;
} else {
Timber.e("Still Unknown curve OID: %s", asn1CurveOidYubikey.getId());
return asn1CurveOid;
}
}
return asn1CurveOid;
}
private static byte[] asn1ToOidField(ASN1ObjectIdentifier oidAsn1) {
byte[] encodedAsn1Oid;
try {
encodedAsn1Oid = oidAsn1.getEncoded();
} catch (IOException e) {
throw new IllegalStateException("Failed to encode curve OID!");
}
byte[] oidField = new byte[encodedAsn1Oid.length - 2];
System.arraycopy(encodedAsn1Oid, 2, oidField, 0, encodedAsn1Oid.length - 2);
return oidField;
}
private static ASN1ObjectIdentifier oidFieldToOidAsn1(byte[] oidField) {
final byte[] boid = new byte[2 + oidField.length];
boid[0] = (byte) 0x06;
boid[1] = (byte) oidField.length;
System.arraycopy(oidField, 0, boid, 2, oidField.length);
return ASN1ObjectIdentifier.getInstance(boid);
}
public enum ECAlgorithmFormat {
ECDH((byte) 18, true, false),
ECDH_WITH_PUBKEY((byte) 18, true, true),
ECDSA((byte) 19, false, false),
ECDSA_WITH_PUBKEY((byte) 19, false, true);
ECDH((byte) PublicKeyAlgorithmTags.ECDH, true, false),
ECDH_WITH_PUBKEY((byte) PublicKeyAlgorithmTags.ECDH, true, true),
ECDSA((byte) PublicKeyAlgorithmTags.ECDSA, false, false),
ECDSA_WITH_PUBKEY((byte) PublicKeyAlgorithmTags.ECDSA, false, true);
private final byte mValue;
private final byte mAlgorithmId;
private final boolean mIsECDH;
private final boolean mWithPubkey;
ECAlgorithmFormat(final byte value, final boolean isECDH, final boolean withPubkey) {
mValue = value;
ECAlgorithmFormat(final byte algorithmId, final boolean isECDH, final boolean withPubkey) {
mAlgorithmId = algorithmId;
mIsECDH = isECDH;
mWithPubkey = withPubkey;
}
public static ECKeyFormat.ECAlgorithmFormat from(final byte bFirst, final byte bLast) {
for (ECKeyFormat.ECAlgorithmFormat format : values()) {
if (format.mValue == bFirst && ((bLast == (byte) 0xff) == format.isWithPubkey())) {
if (format.mAlgorithmId == bFirst &&
((bLast == ATTRS_IMPORT_FORMAT_WITH_PUBKEY) == format.isWithPubkey())) {
return format;
}
}
return null;
}
public final byte getValue() {
return mValue;
public final byte getAlgorithmId() {
return mAlgorithmId;
}
public final boolean isECDH() {
@ -86,7 +174,8 @@ public class ECKeyFormat extends KeyFormat {
}
public void addToSaveKeyringParcel(SaveKeyringParcel.Builder builder, int keyFlags) {
final X9ECParameters params = NISTNamedCurves.getByOID(mECCurveOID);
ASN1ObjectIdentifier oidAsn1 = asn1ParseOid();
final X9ECParameters params = NISTNamedCurves.getByOID(oidAsn1);
final ECCurve curve = params.getCurve();
SaveKeyringParcel.Algorithm algo = SaveKeyringParcel.Algorithm.ECDSA;
@ -96,14 +185,14 @@ public class ECKeyFormat extends KeyFormat {
}
SaveKeyringParcel.Curve scurve;
if (mECCurveOID.equals(NISTNamedCurves.getOID("P-256"))) {
if (oidAsn1.equals(NISTNamedCurves.getOID("P-256"))) {
scurve = SaveKeyringParcel.Curve.NIST_P256;
} else if (mECCurveOID.equals(NISTNamedCurves.getOID("P-384"))) {
} else if (oidAsn1.equals(NISTNamedCurves.getOID("P-384"))) {
scurve = SaveKeyringParcel.Curve.NIST_P384;
} else if (mECCurveOID.equals(NISTNamedCurves.getOID("P-521"))) {
} else if (oidAsn1.equals(NISTNamedCurves.getOID("P-521"))) {
scurve = SaveKeyringParcel.Curve.NIST_P521;
} else {
throw new IllegalArgumentException("Unsupported curve " + mECCurveOID);
throw new IllegalArgumentException("Unsupported curve " + oidAsn1);
}
builder.addSubkeyAdd(SubkeyAdd.createSubkeyAdd(algo, curve.getFieldSize(), scurve, keyFlags, 0L));

20
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/KeyFormat.java
View File

@ -53,19 +53,7 @@ public abstract class KeyFormat {
case PublicKeyAlgorithmTags.ECDH:
case PublicKeyAlgorithmTags.ECDSA:
if (bytes.length < 2) {
throw new IllegalArgumentException("Bad length for EC attributes");
}
int len = bytes.length - 1;
if (bytes[bytes.length - 1] == (byte)0xff) {
len -= 1;
}
final byte[] boid = new byte[2 + len];
boid[0] = (byte)0x06;
boid[1] = (byte)len;
System.arraycopy(bytes, 1, boid, 2, len);
final ASN1ObjectIdentifier oid = ASN1ObjectIdentifier.getInstance(boid);
return new ECKeyFormat(oid, ECKeyFormat.ECAlgorithmFormat.from(bytes[0], bytes[bytes.length - 1]));
return ECKeyFormat.getInstanceFromBytes(bytes);
case PublicKeyAlgorithmTags.EDDSA:
return new EdDSAKeyFormat();
@ -87,11 +75,11 @@ public abstract class KeyFormat {
case RSA_4096:
return new RSAKeyFormat(4096, elen, RSAKeyFormat.RSAAlgorithmFormat.CRT_WITH_MODULUS);
case ECC_P256:
return new ECKeyFormat(NISTNamedCurves.getOID("P-256"), kf);
return ECKeyFormat.getInstance(NISTNamedCurves.getOID("P-256"), kf);
case ECC_P384:
return new ECKeyFormat(NISTNamedCurves.getOID("P-384"), kf);
return ECKeyFormat.getInstance(NISTNamedCurves.getOID("P-384"), kf);
case ECC_P521:
return new ECKeyFormat(NISTNamedCurves.getOID("P-521"), kf);
return ECKeyFormat.getInstance(NISTNamedCurves.getOID("P-521"), kf);
}
throw new IllegalArgumentException("Unsupported Algorithm id " + t);

6
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/SCP11bSecureMessaging.java
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@ -154,7 +154,7 @@ class SCP11bSecureMessaging implements SecureMessaging {
throws NoSuchProviderException, NoSuchAlgorithmException, InvalidParameterSpecException {
final AlgorithmParameters algoParams = AlgorithmParameters.getInstance(SCP11B_KEY_AGREEMENT_KEY_ALGO, PROVIDER);
algoParams.init(new ECGenParameterSpec(ECNamedCurveTable.getName(kf.getCurveOID())));
algoParams.init(new ECGenParameterSpec(ECNamedCurveTable.getName(kf.asn1ParseOid())));
return algoParams.getParameterSpec(ECParameterSpec.class);
}
@ -167,7 +167,7 @@ class SCP11bSecureMessaging implements SecureMessaging {
ecdhFactory = KeyFactory.getInstance(SCP11B_KEY_AGREEMENT_KEY_TYPE, PROVIDER);
}
final X9ECParameters params = NISTNamedCurves.getByOID(kf.getCurveOID());
final X9ECParameters params = NISTNamedCurves.getByOID(kf.asn1ParseOid());
if (params == null) {
throw new InvalidParameterSpecException("unsupported curve");
}
@ -305,7 +305,7 @@ class SCP11bSecureMessaging implements SecureMessaging {
final ECKeyFormat eckf = (ECKeyFormat)kf;
if (eckf.getCurveOID() == null) {
if (eckf.asn1ParseOid() == null) {
throw new SecureMessagingException("unsupported curve");
}

6
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/SecurityTokenUtils.java
View File

@ -43,9 +43,9 @@ public class SecurityTokenUtils {
byte[] attrs = new byte[1 + (oid.length - 2) + 1];
if (slot.equals(KeyType.SIGN))
attrs[0] = ECKeyFormat.ECAlgorithmFormat.ECDSA_WITH_PUBKEY.getValue();
attrs[0] = ECKeyFormat.ECAlgorithmFormat.ECDSA_WITH_PUBKEY.getAlgorithmId();
else {
attrs[0] = ECKeyFormat.ECAlgorithmFormat.ECDH_WITH_PUBKEY.getValue();
attrs[0] = ECKeyFormat.ECAlgorithmFormat.ECDH_WITH_PUBKEY.getAlgorithmId();
}
System.arraycopy(oid, 2, attrs, 1, (oid.length - 2));
@ -174,7 +174,7 @@ public class SecurityTokenUtils {
template.write(Hex.decode("92"));
template.write(encodeLength(data.size()));
if (format.getAlgorithmFormat().isWithPubkey()) {
if (format.ecAlgorithmFormat().isWithPubkey()) {
data.write(Hex.decode("04"));
writeBits(data, publicKey.getW().getAffineX(), csize);
writeBits(data, publicKey.getW().getAffineY(), csize);

4
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/securitytoken/operations/PsoDecryptTokenOp.java
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@ -198,10 +198,10 @@ public class PsoDecryptTokenOp {
private byte[] getEcDecipherPayload(ECKeyFormat eckf, byte[] encryptedPoint) throws CardException {
// TODO is this the right curve?
if (CryptlibObjectIdentifiers.curvey25519.equals(eckf.getCurveOID())) {
if (CryptlibObjectIdentifiers.curvey25519.equals(eckf.asn1ParseOid())) {
return Arrays.copyOfRange(encryptedPoint, 1, 33);
} else {
X9ECParameters x9Params = ECNamedCurveTable.getByOID(eckf.getCurveOID());
X9ECParameters x9Params = ECNamedCurveTable.getByOID(eckf.asn1ParseOid());
ECPoint p = x9Params.getCurve().decodePoint(encryptedPoint);
if (!p.isValid()) {
throw new CardException("Invalid EC point!");