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Code Issues Releases Wiki Activity

Expose encryption mechanism during decryption

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This commit is contained in:
Paul Schaub 2025-04-30 15:57:54 +02:00
parent 3cef99d256
commit 94febc33df
Signed by: vanitasvitae
GPG key ID: 62BEE9264BF17311
4 changed files with 167 additions and 24 deletions
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23
pgpainless-core/src/main/kotlin/org/pgpainless/decryption_verification/MessageMetadata.kt
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@ -9,6 +9,7 @@ import javax.annotation.Nonnull
import org.bouncycastle.bcpg.KeyIdentifier
import org.bouncycastle.openpgp.PGPKeyRing
import org.bouncycastle.openpgp.PGPLiteralData
import org.bouncycastle.openpgp.api.MessageEncryptionMechanism
import org.bouncycastle.openpgp.api.OpenPGPCertificate
import org.pgpainless.algorithm.CompressionAlgorithm
import org.pgpainless.algorithm.StreamEncoding
@ -32,22 +33,34 @@ class MessageMetadata(val message: Message) {
* The [SymmetricKeyAlgorithm] of the outermost encrypted data packet, or null if message is
* unencrypted.
*/
@Deprecated("Deprecated in favor of encryptionMechanism",
replaceWith = ReplaceWith("encryptionMechanism")
)
val encryptionAlgorithm: SymmetricKeyAlgorithm?
get() = encryptionAlgorithms.let { if (it.hasNext()) it.next() else null }
val encryptionMechanism: MessageEncryptionMechanism?
get() = encryptionMechanisms.let { if (it.hasNext()) it.next() else null }
/**
* [Iterator] of each [SymmetricKeyAlgorithm] encountered in the message. The first item
* returned by the iterator is the algorithm of the outermost encrypted data packet, the next
* item that of the next nested encrypted data packet and so on. The iterator might also be
* empty, in case of an unencrypted message.
*/
@Deprecated("Deprecated in favor of encryptionMechanisms",
replaceWith = ReplaceWith("encryptionMechanisms")
)
val encryptionAlgorithms: Iterator<SymmetricKeyAlgorithm>
get() = encryptionLayers.asSequence().map { it.algorithm }.iterator()
val encryptionMechanisms: Iterator<MessageEncryptionMechanism>
get() = encryptionLayers.asSequence().map { it.mechanism }.iterator()
val isEncrypted: Boolean
get() =
if (encryptionAlgorithm == null) false
else encryptionAlgorithm != SymmetricKeyAlgorithm.NULL
if (encryptionMechanism == null) false
else encryptionMechanism!!.symmetricKeyAlgorithm != SymmetricKeyAlgorithm.NULL.algorithmId
fun isEncryptedFor(cert: OpenPGPCertificate): Boolean {
return encryptionLayers.asSequence().any {
@ -472,7 +485,8 @@ class MessageMetadata(val message: Message) {
* @param algorithm symmetric key algorithm used to encrypt the packet.
* @param depth nesting depth at which this packet was encountered.
*/
class EncryptedData(val algorithm: SymmetricKeyAlgorithm, depth: Int) : Layer(depth), Nested {
class EncryptedData(val mechanism: MessageEncryptionMechanism, depth: Int) :
Layer(depth), Nested {
/** [SessionKey] used to decrypt the packet. */
var sessionKey: SessionKey? = null
@ -480,6 +494,9 @@ class MessageMetadata(val message: Message) {
/** List of all recipient key ids to which the packet was encrypted for. */
val recipients: List<KeyIdentifier> = mutableListOf()
val algorithm: SymmetricKeyAlgorithm =
SymmetricKeyAlgorithm.requireFromId(mechanism.symmetricKeyAlgorithm)
fun addRecipients(keyIds: List<KeyIdentifier>) = apply {
(recipients as MutableList).addAll(keyIds)
}

76
pgpainless-core/src/main/kotlin/org/pgpainless/decryption_verification/OpenPgpMessageInputStream.kt
View file

@ -11,9 +11,11 @@ import java.io.OutputStream
import java.util.zip.Inflater
import java.util.zip.InflaterInputStream
import openpgp.openPgpKeyId
import org.bouncycastle.bcpg.AEADEncDataPacket
import org.bouncycastle.bcpg.BCPGInputStream
import org.bouncycastle.bcpg.CompressionAlgorithmTags
import org.bouncycastle.bcpg.KeyIdentifier
import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket
import org.bouncycastle.bcpg.UnsupportedPacketVersionException
import org.bouncycastle.openpgp.PGPCompressedData
import org.bouncycastle.openpgp.PGPEncryptedData
@ -27,6 +29,8 @@ import org.bouncycastle.openpgp.PGPPublicKeyEncryptedData
import org.bouncycastle.openpgp.PGPSessionKey
import org.bouncycastle.openpgp.PGPSignature
import org.bouncycastle.openpgp.PGPSignatureException
import org.bouncycastle.openpgp.api.EncryptedDataPacketType
import org.bouncycastle.openpgp.api.MessageEncryptionMechanism
import org.bouncycastle.openpgp.api.OpenPGPCertificate
import org.bouncycastle.openpgp.api.OpenPGPKey
import org.bouncycastle.openpgp.api.OpenPGPKey.OpenPGPPrivateKey
@ -318,20 +322,38 @@ class OpenPgpMessageInputStream(
}
private fun processEncryptedData(): Boolean {
LOGGER.debug(
"Symmetrically Encrypted Data Packet at depth ${layerMetadata.depth} encountered.")
// TODO: Replace by dedicated encryption packet type input symbols
syntaxVerifier.next(InputSymbol.ENCRYPTED_DATA)
val encDataList = packetInputStream!!.readEncryptedDataList()
if (!encDataList.isIntegrityProtected && !encDataList.get(0).isAEAD) {
val esks = ESKsAndData(encDataList)
when (EncryptedDataPacketType.of(encDataList)!!) {
EncryptedDataPacketType.SEIPDv2 ->
LOGGER.debug(
"Symmetrically Encrypted Integrity Protected Data Packet version 2 at depth " +
"${layerMetadata.depth} encountered.")
EncryptedDataPacketType.SEIPDv1 ->
LOGGER.debug(
"Symmetrically Encrypted Integrity Protected Data Packet version 1 at depth " +
"${layerMetadata.depth} encountered.")
EncryptedDataPacketType.LIBREPGP_OED ->
LOGGER.debug(
"LibrePGP OCB-Encrypted Data Packet at depth " +
"${layerMetadata.depth} encountered.")
EncryptedDataPacketType.SED -> {
LOGGER.debug(
"(Deprecated) Symmetrically Encrypted Data Packet at depth " +
"${layerMetadata.depth} encountered.")
LOGGER.warn("Symmetrically Encrypted Data Packet is not integrity-protected.")
if (!options.isIgnoreMDCErrors()) {
throw MessageNotIntegrityProtectedException()
}
}
}
val esks = SortedESKs(encDataList)
LOGGER.debug(
"Symmetrically Encrypted Integrity-Protected Data has ${esks.skesks.size} SKESK(s) and" +
"Encrypted Data has ${esks.skesks.size} SKESK(s) and" +
" ${esks.pkesks.size + esks.anonPkesks.size} PKESK(s) from which ${esks.anonPkesks.size} PKESK(s)" +
" have an anonymous recipient.")
@ -359,7 +381,7 @@ class OpenPgpMessageInputStream(
val pgpSk = PGPSessionKey(sk.algorithm.algorithmId, sk.key)
val decryptorFactory = api.implementation.sessionKeyDataDecryptorFactory(pgpSk)
val layer = EncryptedData(sk.algorithm, layerMetadata.depth + 1)
val layer = esks.toEncryptedData(sk, layerMetadata.depth + 1)
val skEncData = encDataList.extractSessionKeyEncryptedData()
try {
val decrypted = skEncData.getDataStream(decryptorFactory)
@ -506,7 +528,7 @@ class OpenPgpMessageInputStream(
}
private fun decryptWithPrivateKey(
esks: SortedESKs,
esks: ESKsAndData,
privateKey: PGPKeyPair,
decryptionKeyId: SubkeyIdentifier,
pkesk: PGPPublicKeyEncryptedData
@ -529,7 +551,7 @@ class OpenPgpMessageInputStream(
}
private fun decryptSKESKAndStream(
esks: SortedESKs,
esks: ESKsAndData,
skesk: PGPPBEEncryptedData,
decryptorFactory: PBEDataDecryptorFactory
): Boolean {
@ -537,7 +559,7 @@ class OpenPgpMessageInputStream(
val decrypted = skesk.getDataStream(decryptorFactory)
val sessionKey = SessionKey(skesk.getSessionKey(decryptorFactory))
throwIfUnacceptable(sessionKey.algorithm)
val encryptedData = EncryptedData(sessionKey.algorithm, layerMetadata.depth + 1)
val encryptedData = esks.toEncryptedData(sessionKey, layerMetadata.depth + 1)
encryptedData.sessionKey = sessionKey
encryptedData.addRecipients(esks.pkesks.map { it.keyIdentifier })
LOGGER.debug("Successfully decrypted data with passphrase")
@ -555,7 +577,7 @@ class OpenPgpMessageInputStream(
}
private fun decryptPKESKAndStream(
esks: SortedESKs,
esks: ESKsAndData,
decryptionKeyId: SubkeyIdentifier,
decryptorFactory: PublicKeyDataDecryptorFactory,
pkesk: PGPPublicKeyEncryptedData
@ -565,11 +587,7 @@ class OpenPgpMessageInputStream(
val sessionKey = SessionKey(pkesk.getSessionKey(decryptorFactory))
throwIfUnacceptable(sessionKey.algorithm)
val encryptedData =
EncryptedData(
SymmetricKeyAlgorithm.requireFromId(
pkesk.getSymmetricAlgorithm(decryptorFactory)),
layerMetadata.depth + 1)
val encryptedData = esks.toEncryptedData(sessionKey, layerMetadata.depth)
encryptedData.decryptionKey = decryptionKeyId
encryptedData.sessionKey = sessionKey
encryptedData.addRecipients(esks.pkesks.plus(esks.anonPkesks).map { it.keyIdentifier })
@ -730,7 +748,32 @@ class OpenPgpMessageInputStream(
}
}
private class SortedESKs(esks: PGPEncryptedDataList) {
private class ESKsAndData(private val esks: PGPEncryptedDataList) {
fun toEncryptedData(sk: SessionKey, depth: Int): EncryptedData {
return when (EncryptedDataPacketType.of(esks)!!) {
EncryptedDataPacketType.SED ->
EncryptedData(
MessageEncryptionMechanism.legacyEncryptedNonIntegrityProtected(
sk.algorithm.algorithmId),
depth)
EncryptedDataPacketType.SEIPDv1 ->
EncryptedData(
MessageEncryptionMechanism.integrityProtected(sk.algorithm.algorithmId),
depth)
EncryptedDataPacketType.SEIPDv2 -> {
val seipd2 = esks.encryptedData as SymmetricEncIntegrityPacket
EncryptedData(
MessageEncryptionMechanism.aead(
seipd2.cipherAlgorithm, seipd2.aeadAlgorithm),
depth)
}
EncryptedDataPacketType.LIBREPGP_OED -> {
val oed = esks.encryptedData as AEADEncDataPacket
EncryptedData(MessageEncryptionMechanism.librePgp(oed.algorithm.toInt()), depth)
}
}.also { it.sessionKey = sk }
}
val skesks: List<PGPPBEEncryptedData>
val pkesks: List<PGPPublicKeyEncryptedData>
val anonPkesks: List<PGPPublicKeyEncryptedData>
@ -739,6 +782,7 @@ class OpenPgpMessageInputStream(
skesks = mutableListOf()
pkesks = mutableListOf()
anonPkesks = mutableListOf()
for (esk in esks) {
if (esk is PGPPBEEncryptedData) {
skesks.add(esk)

5
pgpainless-core/src/test/java/org/pgpainless/decryption_verification/MessageMetadataTest.java
View file

@ -4,6 +4,7 @@
package org.pgpainless.decryption_verification;
import org.bouncycastle.openpgp.api.MessageEncryptionMechanism;
import org.junit.JUtils;
import org.junit.jupiter.api.Test;
import org.pgpainless.algorithm.CompressionAlgorithm;
@ -29,8 +30,8 @@ public class MessageMetadataTest {
MessageMetadata.Message message = new MessageMetadata.Message();
MessageMetadata.CompressedData compressedData = new MessageMetadata.CompressedData(CompressionAlgorithm.ZIP, message.getDepth() + 1);
MessageMetadata.EncryptedData encryptedData = new MessageMetadata.EncryptedData(SymmetricKeyAlgorithm.AES_128, compressedData.getDepth() + 1);
MessageMetadata.EncryptedData encryptedData1 = new MessageMetadata.EncryptedData(SymmetricKeyAlgorithm.AES_256, encryptedData.getDepth() + 1);
MessageMetadata.EncryptedData encryptedData = new MessageMetadata.EncryptedData(MessageEncryptionMechanism.integrityProtected(SymmetricKeyAlgorithm.AES_128.getAlgorithmId()), compressedData.getDepth() + 1);
MessageMetadata.EncryptedData encryptedData1 = new MessageMetadata.EncryptedData(MessageEncryptionMechanism.integrityProtected(SymmetricKeyAlgorithm.AES_256.getAlgorithmId()), encryptedData.getDepth() + 1);
MessageMetadata.LiteralData literalData = new MessageMetadata.LiteralData();
message.setChild(compressedData);

81
pgpainless-core/src/test/java/org/pgpainless/encryption_signing/EncryptDecryptTest.java
View file

@ -15,18 +15,25 @@ import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Set;
import org.bouncycastle.bcpg.ArmoredOutputStream;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPSignature;
import org.bouncycastle.openpgp.api.MessageEncryptionMechanism;
import org.bouncycastle.openpgp.api.OpenPGPCertificate;
import org.bouncycastle.openpgp.api.OpenPGPKey;
import org.bouncycastle.util.io.Streams;
import org.junit.jupiter.api.TestTemplate;
import org.junit.jupiter.api.extension.ExtendWith;
import org.pgpainless.PGPainless;
import org.pgpainless.algorithm.AEADAlgorithm;
import org.pgpainless.algorithm.AEADCipherMode;
import org.pgpainless.algorithm.DocumentSignatureType;
import org.pgpainless.algorithm.Feature;
import org.pgpainless.algorithm.KeyFlag;
import org.pgpainless.algorithm.OpenPGPKeyVersion;
import org.pgpainless.algorithm.SymmetricKeyAlgorithm;
import org.pgpainless.decryption_verification.ConsumerOptions;
import org.pgpainless.decryption_verification.DecryptionStream;
@ -34,7 +41,11 @@ import org.pgpainless.decryption_verification.MessageMetadata;
import org.pgpainless.exception.KeyException;
import org.pgpainless.key.SubkeyIdentifier;
import org.pgpainless.key.TestKeys;
import org.pgpainless.key.generation.KeySpec;
import org.pgpainless.key.generation.type.KeyType;
import org.pgpainless.key.generation.type.eddsa_legacy.EdDSALegacyCurve;
import org.pgpainless.key.generation.type.rsa.RsaLength;
import org.pgpainless.key.generation.type.xdh_legacy.XDHLegacySpec;
import org.pgpainless.key.protection.SecretKeyRingProtector;
import org.pgpainless.key.protection.UnprotectedKeysProtector;
import org.pgpainless.util.ArmoredOutputStreamFactory;
@ -306,4 +317,74 @@ public class EncryptDecryptTest {
EncryptionOptions.encryptCommunications(api)
.addRecipient(publicKeys));
}
@TestTemplate
@ExtendWith(TestAllImplementations.class)
public void testEncryptToOnlyV4CertWithOnlySEIPD1Feature() throws PGPException, IOException {
PGPainless api = PGPainless.getInstance();
OpenPGPKey v4Key = api.buildKey(OpenPGPKeyVersion.v4)
.setPrimaryKey(KeySpec.getBuilder(KeyType.EDDSA_LEGACY(EdDSALegacyCurve._Ed25519), KeyFlag.CERTIFY_OTHER, KeyFlag.SIGN_DATA)
.overridePreferredSymmetricKeyAlgorithms(SymmetricKeyAlgorithm.AES_192)
.overrideFeatures(Feature.MODIFICATION_DETECTION)) // the key only supports SEIPD1
.addSubkey(KeySpec.getBuilder(KeyType.XDH_LEGACY(XDHLegacySpec._X25519), KeyFlag.ENCRYPT_COMMS, KeyFlag.ENCRYPT_STORAGE))
.build();
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
EncryptionStream eOut = api.generateMessage().onOutputStream(bOut)
.withOptions(ProducerOptions.encrypt(EncryptionOptions.encryptCommunications()
.addRecipient(v4Key.toCertificate())));
eOut.write(testMessage.getBytes(StandardCharsets.UTF_8));
eOut.close();
ByteArrayInputStream bIn = new ByteArrayInputStream(bOut.toByteArray());
DecryptionStream dIn = PGPainless.decryptAndOrVerify()
.onInputStream(bIn)
.withOptions(ConsumerOptions.get().addDecryptionKey(v4Key));
bOut = new ByteArrayOutputStream();
Streams.pipeAll(dIn, bOut);
dIn.close();
assertEquals(testMessage, bOut.toString());
MessageMetadata metadata = dIn.getMetadata();
MessageEncryptionMechanism encryptionMechanism = metadata.getEncryptionMechanism();
assertEquals(
MessageEncryptionMechanism.integrityProtected(SymmetricKeyAlgorithm.AES_192.getAlgorithmId()),
encryptionMechanism);
}
@TestTemplate
@ExtendWith(TestAllImplementations.class)
public void testEncryptToOnlyV6CertWithOnlySEIPD2Features() throws IOException, PGPException {
PGPainless api = PGPainless.getInstance();
OpenPGPKey v6Key = api.buildKey(OpenPGPKeyVersion.v6)
.setPrimaryKey(KeySpec.getBuilder(KeyType.Ed25519(), KeyFlag.CERTIFY_OTHER, KeyFlag.SIGN_DATA)
.overridePreferredAEADAlgorithms(new AEADCipherMode(AEADAlgorithm.OCB, SymmetricKeyAlgorithm.AES_128))
.overrideFeatures(Feature.MODIFICATION_DETECTION_2)) // the key only supports SEIPD2
.addSubkey(KeySpec.getBuilder(KeyType.X25519(), KeyFlag.ENCRYPT_COMMS, KeyFlag.ENCRYPT_STORAGE))
.build();
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
EncryptionStream eOut = api.generateMessage().onOutputStream(bOut)
.withOptions(ProducerOptions.encrypt(EncryptionOptions.encryptCommunications()
.addRecipient(v6Key.toCertificate())));
eOut.write(testMessage.getBytes(StandardCharsets.UTF_8));
eOut.close();
ByteArrayInputStream bIn = new ByteArrayInputStream(bOut.toByteArray());
DecryptionStream dIn = PGPainless.decryptAndOrVerify()
.onInputStream(bIn)
.withOptions(ConsumerOptions.get().addDecryptionKey(v6Key));
bOut = new ByteArrayOutputStream();
Streams.pipeAll(dIn, bOut);
dIn.close();
assertEquals(testMessage, bOut.toString());
MessageMetadata metadata = dIn.getMetadata();
MessageEncryptionMechanism encryptionMechanism = metadata.getEncryptionMechanism();
assertEquals(
MessageEncryptionMechanism.aead(SymmetricKeyAlgorithm.AES_128.getAlgorithmId(), AEADAlgorithm.OCB.getAlgorithmId()),
encryptionMechanism);
}
}