Progress working on Key minification

This commit is contained in:
Paul Schaub 2022-01-04 17:28:10 +01:00
parent dc6c9182c6
commit 1b4f07c667
3 changed files with 186 additions and 27 deletions

View File

@ -4,19 +4,36 @@
package org.pgpainless.key.modification;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import javax.annotation.Nonnull;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyRing;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.openpgp.PGPUserAttributeSubpacketVector;
import org.pgpainless.algorithm.SignatureType;
import org.pgpainless.implementation.ImplementationFactory;
import org.pgpainless.signature.SignatureFilter;
public class Minifier {
public class KeyCleaner {
public static @Nonnull PGPPublicKeyRing filterThirdPartySignatures(@Nonnull PGPPublicKeyRing certificate) throws PGPException {
List<PGPPublicKey> filteredKeys = new ArrayList<>();
List<PGPPublicKey> keys = new ArrayList<>();
Iterator<PGPPublicKey> keyIterator = certificate.getPublicKeys();
while (keyIterator.hasNext()) {
PGPPublicKey key = keyIterator.next();
keys.add(key);
PGPPublicKey filteredKey = filterSignatures(key,
SignatureFilter.rejectThirdPartySignatures(certificate));
filteredKeys.add(filteredKey);
}
return new PGPPublicKeyRing(filteredKeys);
}
/**
* Return a copy of the passed in key, containing only signatures that pass the given signatureFilter.
@ -28,7 +45,8 @@ public class Minifier {
*/
public static @Nonnull PGPPublicKey filterSignatures(@Nonnull PGPPublicKey key, @Nonnull SignatureFilter signatureFilter)
throws PGPException {
PGPPublicKey newKey = new PGPPublicKey(key.getPublicKeyPacket(), ImplementationFactory.getInstance().getKeyFingerprintCalculator());
PGPPublicKey filteredKey = key;
// Key Signatures
for (SignatureType type : Arrays.asList(
@ -40,8 +58,8 @@ public class Minifier {
Iterator<PGPSignature> iterator = key.getSignaturesOfType(type.getCode());
while (iterator.hasNext()) {
PGPSignature signature = iterator.next();
if (signatureFilter.accept(signature)) {
newKey = PGPPublicKey.addCertification(newKey, signature);
if (!signatureFilter.accept(signature)) {
filteredKey = PGPPublicKey.removeCertification(filteredKey, signature);
}
}
}
@ -52,8 +70,8 @@ public class Minifier {
Iterator<PGPSignature> signatures = key.getSignaturesForID(userId);
while (signatures.hasNext()) {
PGPSignature signature = signatures.next();
if (signatureFilter.accept(signature)) {
newKey = PGPPublicKey.addCertification(newKey, userId, signature);
if (!signatureFilter.accept(signature)) {
filteredKey = PGPPublicKey.removeCertification(filteredKey, userId, signature);
}
}
}
@ -64,12 +82,12 @@ public class Minifier {
Iterator<PGPSignature> signatures = key.getSignaturesForUserAttribute(attribute);
while (signatures.hasNext()) {
PGPSignature signature = signatures.next();
if (signatureFilter.accept(signature)) {
newKey = PGPPublicKey.addCertification(newKey, attribute, signature);
if (!signatureFilter.accept(signature)) {
filteredKey = PGPPublicKey.removeCertification(filteredKey, attribute, signature);
}
}
}
return newKey;
return filteredKey;
}
}

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@ -4,10 +4,15 @@
package org.pgpainless.signature;
import org.bouncycastle.openpgp.PGPSignature;
import javax.annotation.Nonnull;
import org.bouncycastle.bcpg.sig.RevocationKey;
import org.bouncycastle.openpgp.PGPPublicKeyRing;
import org.bouncycastle.openpgp.PGPSignature;
import org.pgpainless.algorithm.SignatureType;
import org.pgpainless.key.info.KeyRingInfo;
import org.pgpainless.signature.subpackets.SignatureSubpacketsUtil;
public abstract class SignatureFilter {
public abstract boolean accept(PGPSignature signature);
@ -58,4 +63,70 @@ public abstract class SignatureFilter {
}
};
}
public static @Nonnull SignatureFilter rejectThirdPartySignatures(
@Nonnull PGPPublicKeyRing certificate) {
return or(
rejectSignaturesByExternalKey(certificate), // sig by us
rejectRevocationsFromNonRevocationKeys(certificate) // external sig, but by legal revocation key
);
}
/**
* Reject signatures made by a key not on the passed in certificate.
* This method does only compare the key-id, it does not perform any sanity checks on the signature.
*
* @param certificate certificate
* @return signature filter
*/
private static @Nonnull SignatureFilter rejectSignaturesByExternalKey(@Nonnull PGPPublicKeyRing certificate) {
return new SignatureFilter() {
@Override
public boolean accept(PGPSignature signature) {
KeyRingInfo info = KeyRingInfo.evaluateForSignature(certificate, signature);
if (info.getPublicKey(signature.getKeyID()) == null) {
return false;
}
return true;
}
};
}
private static @Nonnull SignatureFilter rejectRevocationsFromNonRevocationKeys(@Nonnull PGPPublicKeyRing certificate) {
return new SignatureFilter() {
@Override
public boolean accept(PGPSignature signature) {
if (!SignatureType.isRevocationSignature(signature.getSignatureType())) {
return false;
}
KeyRingInfo info = KeyRingInfo.evaluateForSignature(certificate, signature);
for (String userId : info.getUserIds()) {
PGPSignature certification = info.getLatestUserIdCertification(userId);
RevocationKey revocationKey = SignatureSubpacketsUtil.getRevocationKey(certification);
if (revocationKey == null) {
continue;
}
if (SignatureUtils.wasIssuedBy(revocationKey.getFingerprint(), signature)) {
return true;
}
}
PGPSignature directKeySig = info.getLatestDirectKeySelfSignature();
if (directKeySig == null) {
return false;
}
RevocationKey revocationKey = SignatureSubpacketsUtil.getRevocationKey(directKeySig);
if (revocationKey != null) {
return SignatureUtils.wasIssuedBy(revocationKey.getFingerprint(), signature);
}
return false;
}
};
}
}

View File

@ -1,19 +1,18 @@
package org.pgpainless.key.modification;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import java.io.IOException;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyRing;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.openpgp.PGPSecretKeyRing;
import org.junit.jupiter.api.Test;
import org.pgpainless.PGPainless;
import org.pgpainless.signature.SignatureFilter;
import org.pgpainless.util.ArmorUtils;
public class KeyMinifierTest {
public class KeyCleanerTest {
private static final String ALICE_CERT = "-----BEGIN PGP PUBLIC KEY BLOCK-----\n" +
"Version: PGPainless\n" +
@ -37,6 +36,7 @@ public class KeyMinifierTest {
"Aw==\n" +
"=iERs\n" +
"-----END PGP PUBLIC KEY BLOCK-----\n";
private static final String BOB_CERT = "-----BEGIN PGP PUBLIC KEY BLOCK-----\n" +
"Version: PGPainless\n" +
"Comment: 718B BA02 190A 08F9 1716 AB51 DA16 1EEE 183E 7043\n" +
@ -58,6 +58,7 @@ public class KeyMinifierTest {
"ffrY6ZvoQNUhDK4A/j08wj4F/LQowcJG43m3UyWKOmL0TN5bH5rVwKWaTJQG\n" +
"=EsCN\n" +
"-----END PGP PUBLIC KEY BLOCK-----\n";
private static final String BOB_CERT_WITH_ALICE_CERTIFICATION = "-----BEGIN PGP PUBLIC KEY BLOCK-----\n" +
"Version: PGPainless\n" +
"Comment: 718B BA02 190A 08F9 1716 AB51 DA16 1EEE 183E 7043\n" +
@ -83,23 +84,92 @@ public class KeyMinifierTest {
"=WZ7v\n" +
"-----END PGP PUBLIC KEY BLOCK-----\n";
public static final String EXTERNAL_REVOCATION__REVOCATION_KEY = "-----BEGIN PGP PRIVATE KEY BLOCK-----\n" +
"Version: PGPainless\n" +
"Comment: D0D1 B13D 8BB6 852C 213A 5549 2C52 E85E EED5 E82A\n" +
"Comment: Alice Revocation Key\n" +
"\n" +
"lFgEYdRwyhYJKwYBBAHaRw8BAQdAPC+dFOyKFSBy7Qz2awGPU+vIrX5hBadnrG8N\n" +
"zG3NfrwAAP0WSo5Kn0aQtM7h+8rGpwBo3szsaH7CRD+Gaqp8Q24F2RINtBRBbGlj\n" +
"ZSBSZXZvY2F0aW9uIEtleYiPBBMWCgBBBQJh1HDKCZAsUuhe7tXoKhahBNDRsT2L\n" +
"toUsITpVSSxS6F7u1egqAp4BApsBBZYCAwEABIsJCAcFlQoJCAsCmQEAACf9APwK\n" +
"Gmei73KQT4/z76d/5WuYGxKAOPog/Hz2VAc0jzqzDwEA62lXYaxcBHJn+uHoOG7T\n" +
"oiX2aQnne4iIYcWmOgvY4QycXQRh1HDKEgorBgEEAZdVAQUBAQdATRTv5UOhlt4f\n" +
"fT/PhEugmWVP0XQfhaSM+kzbwN/Xm2cDAQgHAAD/S3osE7TaXrXptLoryqSMY1Cf\n" +
"k7oEwnPbv9FC7Oei09ATvYh1BBgWCgAdBQJh1HDKAp4BApsMBZYCAwEABIsJCAcF\n" +
"lQoJCAsACgkQLFLoXu7V6Cp5NgD/Y7g7/xYuezpDL7Coqmeu6u5XvYKms5UlcZD/\n" +
"b+uhiw4BALx3vGXtJrsbMwHrM0Ecw8fOA9SH2/DsOwmUSLLjFlsOnFgEYdRwyhYJ\n" +
"KwYBBAHaRw8BAQdAvFlxtUwZvzIqSfkcJPZijjIMNChFZlTuk5DhDAuqoAMAAPsH\n" +
"M9DfDGjPW6+XvS9MTTvQlk4BcqiGP1FEYpuaYsnzmhAAiNUEGBYKAH0FAmHUcMoC\n" +
"ngECmwIFlgIDAQAEiwkIBwWVCgkIC18gBBkWCgAGBQJh1HDKAAoJEPuFmxKUmdnK\n" +
"C8UA/jREUb1KkvEIhs4bdYZebRsXoMfzInrn1E//kLZP8xLGAP9R8VuQDKIZd4Q6\n" +
"/DXNcPu7z6Wc75PEvexXk7cEGBX3AAAKCRAsUuhe7tXoKnvIAP9tOz8dckunUWF+\n" +
"KLYPTTXDnHce4VLxNSVOVPor9B9ktAD/doKezBSzrGtqt9/3TTbsu5VJ9i2ZORNB\n" +
"6OfztujPTwc=\n" +
"=EJqs\n" +
"-----END PGP PRIVATE KEY BLOCK-----\n";
public static final String EXTERNAL_REVOCATION__REVOKED_KEY = "-----BEGIN PGP PRIVATE KEY BLOCK-----\n" +
"Version: PGPainless\n" +
"Comment: 2204 7599 9369 DD73 6A62 E639 D801 10F1 B00F 90BB\n" +
"Comment: Alice Key\n" +
"\n" +
"lFgEYdRwyhYJKwYBBAHaRw8BAQdA6qzPVBbQjKapdfbFqE2Cnt4TEtqk6E1DXYQP\n" +
"pnr5fEYAAQDah6jv5E31ez3aspY65vYrXFeuTZluGN6Fbk5QbiWmiRE4iI0EHxYK\n" +
"AD8FAmHUcMoJkNgBEPGwD5C7FqEEIgR1mZNp3XNqYuY52AEQ8bAPkLsXjIAW0NGx\n" +
"PYu2hSwhOlVJLFLoXu7V6CoAAJQOAP9rnCbUZhD8HDi9zLmHxSOwSZ/vebG4SYED\n" +
"bbZ6V9f5qwD9GShXPH/S2dKwuXleJw58wtvjOYyFCXreJVmGKDNHKwSIewQgFgoA\n" +
"LQUCYdRwygmQLFLoXu7V6CoWoQTQ0bE9i7aFLCE6VUksUuhe7tXoKgKHAAKdAwAA\n" +
"kX0BAJuN0LJ5Lxyx773/HuzOR4CFfBE2fZSJ+P49EyLnLMpvAP9H5SlYTCEq7zgK\n" +
"N9bNBIagRdkR7zs+z6uboyjsu9T/ArQJQWxpY2UgS2V5iI8EExYKAEEFAmHUcMoJ\n" +
"kNgBEPGwD5C7FqEEIgR1mZNp3XNqYuY52AEQ8bAPkLsCngECmwEFlgIDAQAEiwkI\n" +
"BwWVCgkICwKZAQAAyLcBANS9fjJMlrx7TAnhiLmgd5taYdQ9IfvI9X1kgaoMhim0\n" +
"AQD4TQngO5VoujJnYNKcUVsk9buYxWBuJ7JY6HkjUM5gCZxdBGHUcMoSCisGAQQB\n" +
"l1UBBQEBB0C6Wg/BwY4DWyRhG+aqCRAjJpFr7OKqli8BrOzz2TgaFAMBCAcAAP9w\n" +
"rL0iSxIGivqRIltn5HhT/2zcptkVKKDvVptjCmAsIA+hiHUEGBYKAB0FAmHUcMoC\n" +
"ngECmwwFlgIDAQAEiwkIBwWVCgkICwAKCRDYARDxsA+Qu7tZAP928VFCnN64PyFr\n" +
"tkV7VoEX+v4JmMnSjiRKlnB4ZCTccwD9EEczALfgB61YZ4EqOC70x4KzwKMWQXG/\n" +
"qRvnB/72XQecWARh1HDKFgkrBgEEAdpHDwEBB0D2ULcyNJo2DjjapnC9zS9Qa9Rp\n" +
"TYEu0Kwy4qFD+Y8XFwAA/1vhpk+/2EXctP9bgd4fA/Bu9KTgzFKFiLwlAO90K7NH\n" +
"EuGI1QQYFgoAfQUCYdRwygKeAQKbAgWWAgMBAASLCQgHBZUKCQgLXyAEGRYKAAYF\n" +
"AmHUcMoACgkQ/VEQxA8tdFf5fQEApz5zynVmb/mbK62yYTE4Z8HjfyIzhqxJp+Wp\n" +
"Xmi3A8ABAI1/8pGiP+3+Uw5v8r4Adh1KlCq1pM01qjxqN2O5KUIMAAoJENgBEPGw\n" +
"D5C7EacA/3esnaCSv+qNcWQMk6iRUoVJhzqhODlz/VLGYnVeyFARAPwPuyGRUOgQ\n" +
"FU0mpQR8D4hmS6eNcvSTRDe3sLahhKFRAA==\n" +
"=S/04\n" +
"-----END PGP PRIVATE KEY BLOCK-----\n";
@Test
public void testMinificationByRemovalOfThirdPartySigs() throws PGPException, IOException {
PGPPublicKeyRing bobCert = PGPainless.readKeyRing().publicKeyRing(BOB_CERT_WITH_ALICE_CERTIFICATION);
PGPPublicKeyRing bobCert = PGPainless.readKeyRing()
.publicKeyRing(BOB_CERT_WITH_ALICE_CERTIFICATION);
PGPPublicKey bobsSignedPrimaryKey = bobCert.getPublicKey();
final PGPPublicKeyRing finalBobCert = bobCert;
PGPPublicKey bobsCleanedPrimaryKey = Minifier.filterSignatures(bobsSignedPrimaryKey, new SignatureFilter() {
@Override
public boolean accept(PGPSignature signature) {
// Quick, unsafe way of checking if sig was made by some of bobs keys
return finalBobCert.getPublicKey(signature.getKeyID()) != null;
}
});
PGPPublicKey bobsCleanedPrimaryKey = KeyCleaner.filterSignatures(bobsSignedPrimaryKey, SignatureFilter.rejectThirdPartySignatures(bobCert));
bobCert = PGPPublicKeyRing.insertPublicKey(bobCert, bobsCleanedPrimaryKey);
assertEquals(ArmorUtils.toAsciiArmoredString(bobCert), BOB_CERT);
assertArrayEquals(bobCert.getEncoded(), PGPainless.readKeyRing().publicKeyRing(BOB_CERT).getEncoded());
}
@Test
public void testMinifyFreshKeyDoesNotChange()
throws PGPException, IOException {
PGPPublicKeyRing certificate = PGPainless.readKeyRing().publicKeyRing(ALICE_CERT);
PGPPublicKeyRing cleaned = KeyCleaner.filterThirdPartySignatures(certificate);
assertArrayEquals(certificate.getEncoded(), cleaned.getEncoded());
}
@Test
public void testRevocationByRevocationKeyIsNotRemoved() throws IOException, PGPException {
PGPSecretKeyRing revocationKey = PGPainless.readKeyRing().secretKeyRing(EXTERNAL_REVOCATION__REVOCATION_KEY);
PGPSecretKeyRing revokedKey = PGPainless.readKeyRing().secretKeyRing(EXTERNAL_REVOCATION__REVOKED_KEY);
PGPPublicKeyRing revokedCert = PGPainless.extractCertificate(revokedKey);
PGPPublicKeyRing cleanedCert = KeyCleaner.filterThirdPartySignatures(revokedCert);
assertArrayEquals(revokedCert.getEncoded(), cleanedCert.getEncoded());
}
}