open-keychain/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerify.java
2014-09-18 15:28:51 +02:00

901 lines
36 KiB
Java

/*
* Copyright (C) 2012-2014 Dominik Schürmann <dominik@dominikschuermann.de>
* Copyright (C) 2010-2014 Thialfihar <thi@thialfihar.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.pgp;
import android.webkit.MimeTypeMap;
import org.openintents.openpgp.OpenPgpMetadata;
import org.spongycastle.bcpg.ArmoredInputStream;
import org.spongycastle.openpgp.PGPCompressedData;
import org.spongycastle.openpgp.PGPEncryptedData;
import org.spongycastle.openpgp.PGPEncryptedDataList;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPLiteralData;
import org.spongycastle.openpgp.PGPObjectFactory;
import org.spongycastle.openpgp.PGPOnePassSignature;
import org.spongycastle.openpgp.PGPOnePassSignatureList;
import org.spongycastle.openpgp.PGPPBEEncryptedData;
import org.spongycastle.openpgp.PGPPublicKeyEncryptedData;
import org.spongycastle.openpgp.PGPSignature;
import org.spongycastle.openpgp.PGPSignatureList;
import org.spongycastle.openpgp.PGPUtil;
import org.spongycastle.openpgp.operator.PBEDataDecryptorFactory;
import org.spongycastle.openpgp.operator.PGPDigestCalculatorProvider;
import org.spongycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
import org.spongycastle.openpgp.operator.jcajce.JcaKeyFingerprintCalculator;
import org.spongycastle.openpgp.operator.jcajce.JcaPGPContentVerifierBuilderProvider;
import org.spongycastle.openpgp.operator.jcajce.JcaPGPDigestCalculatorProviderBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePBEDataDecryptorFactoryBuilder;
import org.spongycastle.openpgp.operator.jcajce.NfcSyncPublicKeyDataDecryptorFactoryBuilder;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.R;
import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
import org.sufficientlysecure.keychain.provider.KeychainContract.KeyRings;
import org.sufficientlysecure.keychain.provider.ProviderHelper;
import org.sufficientlysecure.keychain.service.results.DecryptVerifyResult;
import org.sufficientlysecure.keychain.service.results.OperationResult.LogType;
import org.sufficientlysecure.keychain.service.results.OperationResult.OperationLog;
import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
import org.sufficientlysecure.keychain.util.InputData;
import org.sufficientlysecure.keychain.util.Log;
import org.sufficientlysecure.keychain.util.ProgressScaler;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLConnection;
import java.security.SignatureException;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;
/**
* This class uses a Builder pattern!
*/
public class PgpDecryptVerify {
private ProviderHelper mProviderHelper;
private PassphraseCacheInterface mPassphraseCache;
private InputData mData;
private OutputStream mOutStream;
private Progressable mProgressable;
private boolean mAllowSymmetricDecryption;
private String mPassphrase;
private Set<Long> mAllowedKeyIds;
private boolean mDecryptMetadataOnly;
private byte[] mDecryptedSessionKey;
private PgpDecryptVerify(Builder builder) {
// private Constructor can only be called from Builder
this.mProviderHelper = builder.mProviderHelper;
this.mPassphraseCache = builder.mPassphraseCache;
this.mData = builder.mData;
this.mOutStream = builder.mOutStream;
this.mProgressable = builder.mProgressable;
this.mAllowSymmetricDecryption = builder.mAllowSymmetricDecryption;
this.mPassphrase = builder.mPassphrase;
this.mAllowedKeyIds = builder.mAllowedKeyIds;
this.mDecryptMetadataOnly = builder.mDecryptMetadataOnly;
this.mDecryptedSessionKey = builder.mDecryptedSessionKey;
}
public static class Builder {
// mandatory parameter
private ProviderHelper mProviderHelper;
private PassphraseCacheInterface mPassphraseCache;
private InputData mData;
private OutputStream mOutStream;
// optional
private Progressable mProgressable = null;
private boolean mAllowSymmetricDecryption = true;
private String mPassphrase = null;
private Set<Long> mAllowedKeyIds = null;
private boolean mDecryptMetadataOnly = false;
private byte[] mDecryptedSessionKey = null;
public Builder(ProviderHelper providerHelper, PassphraseCacheInterface passphraseCache,
InputData data, OutputStream outStream) {
mProviderHelper = providerHelper;
mPassphraseCache = passphraseCache;
mData = data;
mOutStream = outStream;
}
public Builder setProgressable(Progressable progressable) {
mProgressable = progressable;
return this;
}
public Builder setAllowSymmetricDecryption(boolean allowSymmetricDecryption) {
mAllowSymmetricDecryption = allowSymmetricDecryption;
return this;
}
public Builder setPassphrase(String passphrase) {
mPassphrase = passphrase;
return this;
}
/**
* Allow these key ids alone for decryption.
* This means only ciphertexts encrypted for one of these private key can be decrypted.
*/
public Builder setAllowedKeyIds(Set<Long> allowedKeyIds) {
mAllowedKeyIds = allowedKeyIds;
return this;
}
/**
* If enabled, the actual decryption/verification of the content will not be executed.
* The metadata only will be decrypted and returned.
*/
public Builder setDecryptMetadataOnly(boolean decryptMetadataOnly) {
mDecryptMetadataOnly = decryptMetadataOnly;
return this;
}
public Builder setNfcState(byte[] decryptedSessionKey) {
mDecryptedSessionKey = decryptedSessionKey;
return this;
}
public PgpDecryptVerify build() {
return new PgpDecryptVerify(this);
}
}
public void updateProgress(int message, int current, int total) {
if (mProgressable != null) {
mProgressable.setProgress(message, current, total);
}
}
public void updateProgress(int current, int total) {
if (mProgressable != null) {
mProgressable.setProgress(current, total);
}
}
/**
* Decrypts and/or verifies data based on parameters of class
*/
public DecryptVerifyResult execute() {
try {
// automatically works with ascii armor input and binary
InputStream in = PGPUtil.getDecoderStream(mData.getInputStream());
if (in instanceof ArmoredInputStream) {
ArmoredInputStream aIn = (ArmoredInputStream) in;
// it is ascii armored
Log.d(Constants.TAG, "ASCII Armor Header Line: " + aIn.getArmorHeaderLine());
if (aIn.isClearText()) {
// a cleartext signature, verify it with the other method
return verifyCleartextSignature(aIn, 0);
}
// else: ascii armored encryption! go on...
}
return decryptVerify(in, 0);
} catch (PGPException e) {
OperationLog log = new OperationLog();
log.add(LogType.MSG_DC_ERROR_PGP_EXCEPTION, 1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
} catch (IOException e) {
OperationLog log = new OperationLog();
log.add(LogType.MSG_DC_ERROR_IO, 1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
}
/**
* Decrypt and/or verifies binary or ascii armored pgp
*/
private DecryptVerifyResult decryptVerify(InputStream in, int indent) throws IOException, PGPException {
OperationLog log = new OperationLog();
log.add(LogType.MSG_DC, indent);
indent += 1;
PGPObjectFactory pgpF = new PGPObjectFactory(in, new JcaKeyFingerprintCalculator());
PGPEncryptedDataList enc;
Object o = pgpF.nextObject();
int currentProgress = 0;
updateProgress(R.string.progress_reading_data, currentProgress, 100);
if (o instanceof PGPEncryptedDataList) {
enc = (PGPEncryptedDataList) o;
} else {
enc = (PGPEncryptedDataList) pgpF.nextObject();
}
if (enc == null) {
log.add(LogType.MSG_DC_ERROR_INVALID_SIGLIST, indent);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
InputStream clear;
PGPEncryptedData encryptedData;
PGPPublicKeyEncryptedData encryptedDataAsymmetric = null;
PGPPBEEncryptedData encryptedDataSymmetric = null;
CanonicalizedSecretKey secretEncryptionKey = null;
Iterator<?> it = enc.getEncryptedDataObjects();
boolean asymmetricPacketFound = false;
boolean symmetricPacketFound = false;
boolean anyPacketFound = false;
// go through all objects and find one we can decrypt
while (it.hasNext()) {
Object obj = it.next();
if (obj instanceof PGPPublicKeyEncryptedData) {
anyPacketFound = true;
currentProgress += 2;
updateProgress(R.string.progress_finding_key, currentProgress, 100);
PGPPublicKeyEncryptedData encData = (PGPPublicKeyEncryptedData) obj;
long subKeyId = encData.getKeyID();
log.add(LogType.MSG_DC_ASYM, indent,
KeyFormattingUtils.convertKeyIdToHex(subKeyId));
CanonicalizedSecretKeyRing secretKeyRing;
try {
// get actual keyring object based on master key id
secretKeyRing = mProviderHelper.getCanonicalizedSecretKeyRing(
KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(subKeyId)
);
} catch (ProviderHelper.NotFoundException e) {
// continue with the next packet in the while loop
log.add(LogType.MSG_DC_ASKIP_NO_KEY, indent +1);
continue;
}
if (secretKeyRing == null) {
// continue with the next packet in the while loop
log.add(LogType.MSG_DC_ASKIP_NO_KEY, indent +1);
continue;
}
// get subkey which has been used for this encryption packet
secretEncryptionKey = secretKeyRing.getSecretKey(subKeyId);
if (secretEncryptionKey == null) {
// should actually never happen, so no need to be more specific.
log.add(LogType.MSG_DC_ASKIP_NO_KEY, indent +1);
continue;
}
// allow only specific keys for decryption?
if (mAllowedKeyIds != null) {
long masterKeyId = secretEncryptionKey.getRing().getMasterKeyId();
Log.d(Constants.TAG, "encData.getKeyID(): " + subKeyId);
Log.d(Constants.TAG, "mAllowedKeyIds: " + mAllowedKeyIds);
Log.d(Constants.TAG, "masterKeyId: " + masterKeyId);
if (!mAllowedKeyIds.contains(masterKeyId)) {
// this key is in our db, but NOT allowed!
// continue with the next packet in the while loop
log.add(LogType.MSG_DC_ASKIP_NOT_ALLOWED, indent +1);
continue;
}
}
/* secret key exists in database and is allowed! */
asymmetricPacketFound = true;
encryptedDataAsymmetric = encData;
// if no passphrase was explicitly set try to get it from the cache service
if (mPassphrase == null) {
try {
// returns "" if key has no passphrase
mPassphrase = mPassphraseCache.getCachedPassphrase(subKeyId);
log.add(LogType.MSG_DC_PASS_CACHED, indent +1);
} catch (PassphraseCacheInterface.NoSecretKeyException e) {
log.add(LogType.MSG_DC_ERROR_NO_KEY, indent +1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
// if passphrase was not cached, return here indicating that a passphrase is missing!
if (mPassphrase == null) {
log.add(LogType.MSG_DC_PENDING_PASSPHRASE, indent +1);
DecryptVerifyResult result =
new DecryptVerifyResult(DecryptVerifyResult.RESULT_PENDING_ASYM_PASSPHRASE, log);
result.setKeyIdPassphraseNeeded(subKeyId);
return result;
}
}
// break out of while, only decrypt the first packet where we have a key
break;
} else if (obj instanceof PGPPBEEncryptedData) {
anyPacketFound = true;
log.add(LogType.MSG_DC_SYM, indent);
if (! mAllowSymmetricDecryption) {
log.add(LogType.MSG_DC_SYM_SKIP, indent +1);
continue;
}
/*
* When mAllowSymmetricDecryption == true and we find a data packet here,
* we do not search for other available asymmetric packets!
*/
symmetricPacketFound = true;
encryptedDataSymmetric = (PGPPBEEncryptedData) obj;
// if no passphrase is given, return here
// indicating that a passphrase is missing!
if (mPassphrase == null) {
log.add(LogType.MSG_DC_PENDING_PASSPHRASE, indent +1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_PENDING_SYM_PASSPHRASE, log);
}
// break out of while, only decrypt the first packet
break;
}
}
// More data, just acknowledge and ignore.
while (it.hasNext()) {
Object obj = it.next();
if (obj instanceof PGPPublicKeyEncryptedData) {
PGPPublicKeyEncryptedData encData = (PGPPublicKeyEncryptedData) obj;
long subKeyId = encData.getKeyID();
log.add(LogType.MSG_DC_TRAIL_ASYM, indent,
KeyFormattingUtils.convertKeyIdToHex(subKeyId));
} else if (obj instanceof PGPPBEEncryptedData) {
log.add(LogType.MSG_DC_TRAIL_SYM, indent);
} else {
log.add(LogType.MSG_DC_TRAIL_UNKNOWN, indent);
}
}
log.add(LogType.MSG_DC_PREP_STREAMS, indent);
// we made sure above one of these two would be true
if (symmetricPacketFound) {
currentProgress += 2;
updateProgress(R.string.progress_preparing_streams, currentProgress, 100);
PGPDigestCalculatorProvider digestCalcProvider = new JcaPGPDigestCalculatorProviderBuilder()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build();
PBEDataDecryptorFactory decryptorFactory = new JcePBEDataDecryptorFactoryBuilder(
digestCalcProvider).setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME).build(
mPassphrase.toCharArray());
clear = encryptedDataSymmetric.getDataStream(decryptorFactory);
encryptedData = encryptedDataSymmetric;
} else if (asymmetricPacketFound) {
currentProgress += 2;
updateProgress(R.string.progress_extracting_key, currentProgress, 100);
try {
log.add(LogType.MSG_DC_UNLOCKING, indent +1);
if (!secretEncryptionKey.unlock(mPassphrase)) {
log.add(LogType.MSG_DC_ERROR_BAD_PASSPHRASE, indent +1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
} catch (PgpGeneralException e) {
log.add(LogType.MSG_DC_ERROR_EXTRACT_KEY, indent +1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
currentProgress += 2;
updateProgress(R.string.progress_preparing_streams, currentProgress, 100);
try {
PublicKeyDataDecryptorFactory decryptorFactory
= secretEncryptionKey.getDecryptorFactory(mDecryptedSessionKey);
clear = encryptedDataAsymmetric.getDataStream(decryptorFactory);
} catch (NfcSyncPublicKeyDataDecryptorFactoryBuilder.NfcInteractionNeeded e) {
log.add(LogType.MSG_DC_PENDING_NFC, indent +1);
DecryptVerifyResult result =
new DecryptVerifyResult(DecryptVerifyResult.RESULT_PENDING_NFC, log);
result.setNfcState(e.encryptedSessionKey, mPassphrase);
return result;
}
encryptedData = encryptedDataAsymmetric;
} else {
// If we didn't find any useful data, error out
// no packet has been found where we have the corresponding secret key in our db
log.add(
anyPacketFound ? LogType.MSG_DC_ERROR_NO_KEY : LogType.MSG_DC_ERROR_NO_DATA, indent +1);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
PGPObjectFactory plainFact = new PGPObjectFactory(clear, new JcaKeyFingerprintCalculator());
Object dataChunk = plainFact.nextObject();
OpenPgpSignatureResultBuilder signatureResultBuilder = new OpenPgpSignatureResultBuilder();
int signatureIndex = -1;
CanonicalizedPublicKeyRing signingRing = null;
CanonicalizedPublicKey signingKey = null;
log.add(LogType.MSG_DC_CLEAR, indent);
indent += 1;
if (dataChunk instanceof PGPCompressedData) {
log.add(LogType.MSG_DC_CLEAR_DECOMPRESS, indent +1);
currentProgress += 2;
updateProgress(R.string.progress_decompressing_data, currentProgress, 100);
PGPCompressedData compressedData = (PGPCompressedData) dataChunk;
PGPObjectFactory fact = new PGPObjectFactory(compressedData.getDataStream(), new JcaKeyFingerprintCalculator());
dataChunk = fact.nextObject();
plainFact = fact;
}
PGPOnePassSignature signature = null;
if (dataChunk instanceof PGPOnePassSignatureList) {
log.add(LogType.MSG_DC_CLEAR_SIGNATURE, indent +1);
currentProgress += 2;
updateProgress(R.string.progress_processing_signature, currentProgress, 100);
PGPOnePassSignatureList sigList = (PGPOnePassSignatureList) dataChunk;
// go through all signatures
// and find out for which signature we have a key in our database
for (int i = 0; i < sigList.size(); ++i) {
try {
long sigKeyId = sigList.get(i).getKeyID();
signingRing = mProviderHelper.getCanonicalizedPublicKeyRing(
KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(sigKeyId)
);
signingKey = signingRing.getPublicKey(sigKeyId);
signatureIndex = i;
} catch (ProviderHelper.NotFoundException e) {
Log.d(Constants.TAG, "key not found, trying next signature...");
}
}
if (signingKey != null) {
// key found in our database!
signature = sigList.get(signatureIndex);
signatureResultBuilder.initValid(signingRing, signingKey);
JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
new JcaPGPContentVerifierBuilderProvider()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
signature.init(contentVerifierBuilderProvider, signingKey.getPublicKey());
} else {
// no key in our database -> return "unknown pub key" status including the first key id
if (!sigList.isEmpty()) {
signatureResultBuilder.setSignatureAvailable(true);
signatureResultBuilder.setKnownKey(false);
signatureResultBuilder.setKeyId(sigList.get(0).getKeyID());
}
}
dataChunk = plainFact.nextObject();
}
if (dataChunk instanceof PGPSignatureList) {
// skip
dataChunk = plainFact.nextObject();
}
OpenPgpMetadata metadata;
if (dataChunk instanceof PGPLiteralData) {
log.add(LogType.MSG_DC_CLEAR_DATA, indent +1);
indent += 2;
currentProgress += 4;
updateProgress(R.string.progress_decrypting, currentProgress, 100);
PGPLiteralData literalData = (PGPLiteralData) dataChunk;
// TODO: how to get the real original size?
// this is the encrypted size so if we enable compression this value is wrong!
long originalSize = mData.getSize() - mData.getStreamPosition();
if (originalSize < 0) {
originalSize = 0;
}
String originalFilename = literalData.getFileName();
String mimeType = null;
if (literalData.getFormat() == PGPLiteralData.TEXT
|| literalData.getFormat() == PGPLiteralData.UTF8) {
mimeType = "text/plain";
} else {
// TODO: better would be: https://github.com/open-keychain/open-keychain/issues/753
// try to guess from file ending
String extension = MimeTypeMap.getFileExtensionFromUrl(originalFilename);
if (extension != null) {
MimeTypeMap mime = MimeTypeMap.getSingleton();
mimeType = mime.getMimeTypeFromExtension(extension);
}
if (mimeType == null) {
mimeType = URLConnection.guessContentTypeFromName(originalFilename);
}
if (mimeType == null) {
mimeType = "*/*";
}
}
metadata = new OpenPgpMetadata(
originalFilename,
mimeType,
literalData.getModificationTime().getTime(),
originalSize);
if ( ! originalFilename.equals("")) {
log.add(LogType.MSG_DC_CLEAR_META_FILE, indent + 1, originalFilename);
}
log.add(LogType.MSG_DC_CLEAR_META_MIME, indent +1,
mimeType);
log.add(LogType.MSG_DC_CLEAR_META_TIME, indent +1,
new Date(literalData.getModificationTime().getTime()).toString());
if (originalSize != 0) {
log.add(LogType.MSG_DC_CLEAR_META_SIZE, indent + 1,
Long.toString(originalSize));
}
// return here if we want to decrypt the metadata only
if (mDecryptMetadataOnly) {
log.add(LogType.MSG_DC_OK_META_ONLY, indent);
DecryptVerifyResult result =
new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
result.setDecryptMetadata(metadata);
return result;
}
int endProgress;
if (signature != null) {
endProgress = 90;
} else if (encryptedData.isIntegrityProtected()) {
endProgress = 95;
} else {
endProgress = 100;
}
ProgressScaler progressScaler =
new ProgressScaler(mProgressable, currentProgress, endProgress, 100);
InputStream dataIn = literalData.getInputStream();
long alreadyWritten = 0;
long wholeSize = mData.getSize() - mData.getStreamPosition();
int length;
byte[] buffer = new byte[1 << 16];
while ((length = dataIn.read(buffer)) > 0) {
mOutStream.write(buffer, 0, length);
// update signature buffer if signature is also present
if (signature != null) {
signature.update(buffer, 0, length);
}
alreadyWritten += length;
if (wholeSize > 0) {
long progress = 100 * alreadyWritten / wholeSize;
// stop at 100% for wrong file sizes...
if (progress > 100) {
progress = 100;
}
progressScaler.setProgress((int) progress, 100);
} else {
// TODO: slow annealing to fake a progress?
}
}
if (signature != null) {
updateProgress(R.string.progress_verifying_signature, 90, 100);
log.add(LogType.MSG_DC_CLEAR_SIGNATURE_CHECK, indent);
PGPSignatureList signatureList = (PGPSignatureList) plainFact.nextObject();
PGPSignature messageSignature = signatureList.get(signatureIndex);
// these are not cleartext signatures!
// TODO: what about binary signatures?
signatureResultBuilder.setSignatureOnly(false);
// Verify signature and check binding signatures
boolean validSignature = signature.verify(messageSignature);
if (validSignature) {
log.add(LogType.MSG_DC_CLEAR_SIGNATURE_OK, indent +1);
} else {
log.add(LogType.MSG_DC_CLEAR_SIGNATURE_BAD, indent +1);
}
signatureResultBuilder.setValidSignature(validSignature);
}
indent -= 1;
} else {
// If there is no literalData, we don't have any metadata
metadata = null;
}
if (encryptedData.isIntegrityProtected()) {
updateProgress(R.string.progress_verifying_integrity, 95, 100);
if (encryptedData.verify()) {
log.add(LogType.MSG_DC_INTEGRITY_CHECK_OK, indent);
} else {
log.add(LogType.MSG_DC_ERROR_INTEGRITY_CHECK, indent);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
} else {
// If no valid signature is present:
// Handle missing integrity protection like failed integrity protection!
// The MDC packet can be stripped by an attacker!
if (!signatureResultBuilder.isValidSignature()) {
log.add(LogType.MSG_DC_ERROR_INTEGRITY_CHECK, indent);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
}
updateProgress(R.string.progress_done, 100, 100);
log.add(LogType.MSG_DC_OK, indent);
// Return a positive result, with metadata and verification info
DecryptVerifyResult result =
new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
result.setDecryptMetadata(metadata);
result.setSignatureResult(signatureResultBuilder.build());
return result;
}
/**
* This method verifies cleartext signatures
* as defined in http://tools.ietf.org/html/rfc4880#section-7
* <p/>
* The method is heavily based on
* pg/src/main/java/org/spongycastle/openpgp/examples/ClearSignedFileProcessor.java
*/
private DecryptVerifyResult verifyCleartextSignature(ArmoredInputStream aIn, int indent)
throws IOException, PGPException {
OperationLog log = new OperationLog();
OpenPgpSignatureResultBuilder signatureResultBuilder = new OpenPgpSignatureResultBuilder();
// cleartext signatures are never encrypted ;)
signatureResultBuilder.setSignatureOnly(true);
ByteArrayOutputStream out = new ByteArrayOutputStream();
updateProgress(R.string.progress_done, 0, 100);
ByteArrayOutputStream lineOut = new ByteArrayOutputStream();
int lookAhead = readInputLine(lineOut, aIn);
byte[] lineSep = getLineSeparator();
byte[] line = lineOut.toByteArray();
out.write(line, 0, getLengthWithoutSeparator(line));
out.write(lineSep);
while (lookAhead != -1 && aIn.isClearText()) {
lookAhead = readInputLine(lineOut, lookAhead, aIn);
line = lineOut.toByteArray();
out.write(line, 0, getLengthWithoutSeparator(line));
out.write(lineSep);
}
out.close();
byte[] clearText = out.toByteArray();
mOutStream.write(clearText);
updateProgress(R.string.progress_processing_signature, 60, 100);
PGPObjectFactory pgpFact = new PGPObjectFactory(aIn, new JcaKeyFingerprintCalculator());
PGPSignatureList sigList = (PGPSignatureList) pgpFact.nextObject();
if (sigList == null) {
log.add(LogType.MSG_DC_ERROR_INVALID_SIGLIST, 0);
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
CanonicalizedPublicKeyRing signingRing = null;
CanonicalizedPublicKey signingKey = null;
int signatureIndex = -1;
// go through all signatures
// and find out for which signature we have a key in our database
for (int i = 0; i < sigList.size(); ++i) {
try {
long sigKeyId = sigList.get(i).getKeyID();
signingRing = mProviderHelper.getCanonicalizedPublicKeyRing(
KeyRings.buildUnifiedKeyRingsFindBySubkeyUri(sigKeyId)
);
signingKey = signingRing.getPublicKey(sigKeyId);
signatureIndex = i;
} catch (ProviderHelper.NotFoundException e) {
Log.d(Constants.TAG, "key not found, trying next signature...");
}
}
PGPSignature signature = null;
if (signingKey != null) {
// key found in our database!
signature = sigList.get(signatureIndex);
signatureResultBuilder.initValid(signingRing, signingKey);
JcaPGPContentVerifierBuilderProvider contentVerifierBuilderProvider =
new JcaPGPContentVerifierBuilderProvider()
.setProvider(Constants.BOUNCY_CASTLE_PROVIDER_NAME);
signature.init(contentVerifierBuilderProvider, signingKey.getPublicKey());
} else {
// no key in our database -> return "unknown pub key" status including the first key id
if (!sigList.isEmpty()) {
signatureResultBuilder.setSignatureAvailable(true);
signatureResultBuilder.setKnownKey(false);
signatureResultBuilder.setKeyId(sigList.get(0).getKeyID());
}
}
if (signature != null) try {
updateProgress(R.string.progress_verifying_signature, 90, 100);
log.add(LogType.MSG_DC_CLEAR_SIGNATURE_CHECK, indent);
InputStream sigIn = new BufferedInputStream(new ByteArrayInputStream(clearText));
lookAhead = readInputLine(lineOut, sigIn);
processLine(signature, lineOut.toByteArray());
if (lookAhead != -1) {
do {
lookAhead = readInputLine(lineOut, lookAhead, sigIn);
signature.update((byte) '\r');
signature.update((byte) '\n');
processLine(signature, lineOut.toByteArray());
} while (lookAhead != -1);
}
// Verify signature and check binding signatures
boolean validSignature = signature.verify();
if (validSignature) {
log.add(LogType.MSG_DC_CLEAR_SIGNATURE_OK, indent +1);
} else {
log.add(LogType.MSG_DC_CLEAR_SIGNATURE_BAD, indent +1);
}
signatureResultBuilder.setValidSignature(validSignature);
} catch (SignatureException e) {
return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
}
updateProgress(R.string.progress_done, 100, 100);
log.add(LogType.MSG_DC_OK, indent);
DecryptVerifyResult result = new DecryptVerifyResult(DecryptVerifyResult.RESULT_OK, log);
result.setSignatureResult(signatureResultBuilder.build());
return result;
}
/**
* Mostly taken from ClearSignedFileProcessor in Bouncy Castle
*/
private static void processLine(PGPSignature sig, byte[] line)
throws SignatureException {
int length = getLengthWithoutWhiteSpace(line);
if (length > 0) {
sig.update(line, 0, length);
}
}
private static int readInputLine(ByteArrayOutputStream bOut, InputStream fIn)
throws IOException {
bOut.reset();
int lookAhead = -1;
int ch;
while ((ch = fIn.read()) >= 0) {
bOut.write(ch);
if (ch == '\r' || ch == '\n') {
lookAhead = readPassedEOL(bOut, ch, fIn);
break;
}
}
return lookAhead;
}
private static int readInputLine(ByteArrayOutputStream bOut, int lookAhead, InputStream fIn)
throws IOException {
bOut.reset();
int ch = lookAhead;
do {
bOut.write(ch);
if (ch == '\r' || ch == '\n') {
lookAhead = readPassedEOL(bOut, ch, fIn);
break;
}
} while ((ch = fIn.read()) >= 0);
if (ch < 0) {
lookAhead = -1;
}
return lookAhead;
}
private static int readPassedEOL(ByteArrayOutputStream bOut, int lastCh, InputStream fIn)
throws IOException {
int lookAhead = fIn.read();
if (lastCh == '\r' && lookAhead == '\n') {
bOut.write(lookAhead);
lookAhead = fIn.read();
}
return lookAhead;
}
private static int getLengthWithoutSeparator(byte[] line) {
int end = line.length - 1;
while (end >= 0 && isLineEnding(line[end])) {
end--;
}
return end + 1;
}
private static boolean isLineEnding(byte b) {
return b == '\r' || b == '\n';
}
private static int getLengthWithoutWhiteSpace(byte[] line) {
int end = line.length - 1;
while (end >= 0 && isWhiteSpace(line[end])) {
end--;
}
return end + 1;
}
private static boolean isWhiteSpace(byte b) {
return b == '\r' || b == '\n' || b == '\t' || b == ' ';
}
private static byte[] getLineSeparator() {
String nl = System.getProperty("line.separator");
byte[] nlBytes = new byte[nl.length()];
for (int i = 0; i != nlBytes.length; i++) {
nlBytes[i] = (byte) nl.charAt(i);
}
return nlBytes;
}
}