Merge "APK Signature Scheme v2 signing logic for apksigner-core."

am: 2627b4199f

* commit '2627b4199f539e62a2c96c6c445b187df2177d9b':
  APK Signature Scheme v2 signing logic for apksigner-core.

Change-Id: Id8be4e6625d0dd6378839018597de2c1e6c7e898
This commit is contained in:
Alex Klyubin
2016-05-09 20:21:52 +00:00
committed by android-build-merger
10 changed files with 1177 additions and 0 deletions

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.apk.v2;
/**
* APK Signature Scheme v2 content digest algorithm.
*/
enum ContentDigestAlgorithm {
/** SHA2-256 over 1 MB chunks. */
CHUNKED_SHA256("SHA-256", 256 / 8),
/** SHA2-512 over 1 MB chunks. */
CHUNKED_SHA512("SHA-512", 512 / 8);
private final String mJcaMessageDigestAlgorithm;
private final int mChunkDigestOutputSizeBytes;
private ContentDigestAlgorithm(
String jcaMessageDigestAlgorithm, int chunkDigestOutputSizeBytes) {
mJcaMessageDigestAlgorithm = jcaMessageDigestAlgorithm;
mChunkDigestOutputSizeBytes = chunkDigestOutputSizeBytes;
}
/**
* Returns the {@link java.security.MessageDigest} algorithm used for computing digests of
* chunks by this content digest algorithm.
*/
String getJcaMessageDigestAlgorithm() {
return mJcaMessageDigestAlgorithm;
}
/**
* Returns the size (in bytes) of the digest of a chunk of content.
*/
int getChunkDigestOutputSizeBytes() {
return mChunkDigestOutputSizeBytes;
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.apk.v2;
import com.android.apksigner.core.util.DataSink;
import java.nio.ByteBuffer;
import java.security.MessageDigest;
/**
* Data sink which feeds all received data into the associated {@link MessageDigest} instances. Each
* {@code MessageDigest} instance receives the same data.
*/
class MessageDigestSink implements DataSink {
private final MessageDigest[] mMessageDigests;
MessageDigestSink(MessageDigest[] digests) {
mMessageDigests = digests;
}
@Override
public void consume(byte[] buf, int offset, int length) {
for (MessageDigest md : mMessageDigests) {
md.update(buf, offset, length);
}
}
@Override
public void consume(ByteBuffer buf) {
int originalPosition = buf.position();
for (MessageDigest md : mMessageDigests) {
// Reset the position back to the original because the previous iteration's
// MessageDigest.update set the buffer's position to the buffer's limit.
buf.position(originalPosition);
md.update(buf);
}
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.apk.v2;
import com.android.apksigner.core.internal.util.Pair;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.MGF1ParameterSpec;
import java.security.spec.PSSParameterSpec;
/**
* APK Signature Scheme v2 content digest algorithm.
*/
public enum SignatureAlgorithm {
/**
* RSASSA-PSS with SHA2-256 digest, SHA2-256 MGF1, 32 bytes of salt, trailer: 0xbc, content
* digested using SHA2-256 in 1 MB chunks.
*/
RSA_PSS_WITH_SHA256(
0x0101,
ContentDigestAlgorithm.CHUNKED_SHA256,
"RSA",
Pair.of("SHA256withRSA/PSS",
new PSSParameterSpec(
"SHA-256", "MGF1", MGF1ParameterSpec.SHA256, 256 / 8, 1))),
/**
* RSASSA-PSS with SHA2-512 digest, SHA2-512 MGF1, 64 bytes of salt, trailer: 0xbc, content
* digested using SHA2-512 in 1 MB chunks.
*/
RSA_PSS_WITH_SHA512(
0x0102,
ContentDigestAlgorithm.CHUNKED_SHA512,
"RSA",
Pair.of(
"SHA512withRSA/PSS",
new PSSParameterSpec(
"SHA-512", "MGF1", MGF1ParameterSpec.SHA512, 512 / 8, 1))),
/** RSASSA-PKCS1-v1_5 with SHA2-256 digest, content digested using SHA2-256 in 1 MB chunks. */
RSA_PKCS1_V1_5_WITH_SHA256(
0x0103,
ContentDigestAlgorithm.CHUNKED_SHA256,
"RSA",
Pair.of("SHA256withRSA", null)),
/** RSASSA-PKCS1-v1_5 with SHA2-512 digest, content digested using SHA2-512 in 1 MB chunks. */
RSA_PKCS1_V1_5_WITH_SHA512(
0x0104,
ContentDigestAlgorithm.CHUNKED_SHA512,
"RSA",
Pair.of("SHA512withRSA", null)),
/** ECDSA with SHA2-256 digest, content digested using SHA2-256 in 1 MB chunks. */
ECDSA_WITH_SHA256(
0x0201,
ContentDigestAlgorithm.CHUNKED_SHA256,
"EC",
Pair.of("SHA256withECDSA", null)),
/** ECDSA with SHA2-512 digest, content digested using SHA2-512 in 1 MB chunks. */
ECDSA_WITH_SHA512(
0x0202,
ContentDigestAlgorithm.CHUNKED_SHA512,
"EC",
Pair.of("SHA512withECDSA", null)),
/** DSA with SHA2-256 digest, content digested using SHA2-256 in 1 MB chunks. */
DSA_WITH_SHA256(
0x0301,
ContentDigestAlgorithm.CHUNKED_SHA256,
"DSA",
Pair.of("SHA256withDSA", null));
private final int mId;
private final String mJcaKeyAlgorithm;
private final ContentDigestAlgorithm mContentDigestAlgorithm;
private final Pair<String, ? extends AlgorithmParameterSpec> mJcaSignatureAlgAndParams;
private SignatureAlgorithm(int id,
ContentDigestAlgorithm contentDigestAlgorithm,
String jcaKeyAlgorithm,
Pair<String, ? extends AlgorithmParameterSpec> jcaSignatureAlgAndParams) {
mId = id;
mContentDigestAlgorithm = contentDigestAlgorithm;
mJcaKeyAlgorithm = jcaKeyAlgorithm;
mJcaSignatureAlgAndParams = jcaSignatureAlgAndParams;
}
/**
* Returns the ID of this signature algorithm as used in APK Signature Scheme v2 wire format.
*/
int getId() {
return mId;
}
/**
* Returns the content digest algorithm associated with this signature algorithm.
*/
ContentDigestAlgorithm getContentDigestAlgorithm() {
return mContentDigestAlgorithm;
}
/**
* Returns the JCA {@link java.security.Key} algorithm used by this signature scheme.
*/
String getJcaKeyAlgorithm() {
return mJcaKeyAlgorithm;
}
/**
* Returns the {@link java.security.Signature} algorithm and the {@link AlgorithmParameterSpec}
* (or null if not needed) to parameterize the {@code Signature}.
*/
Pair<String, ? extends AlgorithmParameterSpec> getJcaSignatureAlgorithmAndParams() {
return mJcaSignatureAlgAndParams;
}
static SignatureAlgorithm findById(int id) {
for (SignatureAlgorithm alg : SignatureAlgorithm.values()) {
if (alg.getId() == id) {
return alg;
}
}
return null;
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.apk.v2;
import com.android.apksigner.core.internal.util.ByteBufferSink;
import com.android.apksigner.core.internal.util.Pair;
import com.android.apksigner.core.internal.zip.ZipUtils;
import com.android.apksigner.core.util.DataSource;
import com.android.apksigner.core.util.DataSources;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.security.DigestException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.cert.CertificateEncodingException;
import java.security.cert.X509Certificate;
import java.security.interfaces.ECKey;
import java.security.interfaces.RSAKey;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.X509EncodedKeySpec;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* APK Signature Scheme v2 signer.
*
* <p>APK Signature Scheme v2 is a whole-file signature scheme which aims to protect every single
* bit of the APK, as opposed to the JAR Signature Scheme which protects only the names and
* uncompressed contents of ZIP entries.
*
* <p>TODO: Link to APK Signature Scheme v2 documentation once it's available.
*/
public abstract class V2SchemeSigner {
/*
* The two main goals of APK Signature Scheme v2 are:
* 1. Detect any unauthorized modifications to the APK. This is achieved by making the signature
* cover every byte of the APK being signed.
* 2. Enable much faster signature and integrity verification. This is achieved by requiring
* only a minimal amount of APK parsing before the signature is verified, thus completely
* bypassing ZIP entry decompression and by making integrity verification parallelizable by
* employing a hash tree.
*
* The generated signature block is wrapped into an APK Signing Block and inserted into the
* original APK immediately before the start of ZIP Central Directory. This is to ensure that
* JAR and ZIP parsers continue to work on the signed APK. The APK Signing Block is designed for
* extensibility. For example, a future signature scheme could insert its signatures there as
* well. The contract of the APK Signing Block is that all contents outside of the block must be
* protected by signatures inside the block.
*/
private static final int CONTENT_DIGESTED_CHUNK_MAX_SIZE_BYTES = 1024 * 1024;
private static final byte[] APK_SIGNING_BLOCK_MAGIC =
new byte[] {
0x41, 0x50, 0x4b, 0x20, 0x53, 0x69, 0x67, 0x20,
0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x20, 0x34, 0x32,
};
private static final int APK_SIGNATURE_SCHEME_V2_BLOCK_ID = 0x7109871a;
/**
* Signer configuration.
*/
public static class SignerConfig {
/** Private key. */
public PrivateKey privateKey;
/**
* Certificates, with the first certificate containing the public key corresponding to
* {@link #privateKey}.
*/
public List<X509Certificate> certificates;
/**
* List of signature algorithms with which to sign.
*/
public List<SignatureAlgorithm> signatureAlgorithms;
}
/** Hidden constructor to prevent instantiation. */
private V2SchemeSigner() {}
/**
* Gets the APK Signature Scheme v2 signature algorithms to be used for signing an APK using the
* provided key.
*
* @param minSdkVersion minimum API Level of the platform on which the APK may be installed (see
* AndroidManifest.xml minSdkVersion attribute).
*
* @throws InvalidKeyException if the provided key is not suitable for signing APKs using
* APK Signature Scheme v2
*/
public static List<SignatureAlgorithm> getSuggestedSignatureAlgorithms(
PublicKey signingKey, int minSdkVersion) throws InvalidKeyException {
String keyAlgorithm = signingKey.getAlgorithm();
if ("RSA".equalsIgnoreCase(keyAlgorithm)) {
// Use RSASSA-PKCS1-v1_5 signature scheme instead of RSASSA-PSS to guarantee
// deterministic signatures which make life easier for OTA updates (fewer files
// changed when deterministic signature schemes are used).
// Pick a digest which is no weaker than the key.
int modulusLengthBits = ((RSAKey) signingKey).getModulus().bitLength();
if (modulusLengthBits <= 3072) {
// 3072-bit RSA is roughly 128-bit strong, meaning SHA-256 is a good fit.
return Collections.singletonList(SignatureAlgorithm.RSA_PKCS1_V1_5_WITH_SHA256);
} else {
// Keys longer than 3072 bit need to be paired with a stronger digest to avoid the
// digest being the weak link. SHA-512 is the next strongest supported digest.
return Collections.singletonList(SignatureAlgorithm.RSA_PKCS1_V1_5_WITH_SHA512);
}
} else if ("DSA".equalsIgnoreCase(keyAlgorithm)) {
// DSA is supported only with SHA-256.
return Collections.singletonList(SignatureAlgorithm.DSA_WITH_SHA256);
} else if ("EC".equalsIgnoreCase(keyAlgorithm)) {
// Pick a digest which is no weaker than the key.
int keySizeBits = ((ECKey) signingKey).getParams().getOrder().bitLength();
if (keySizeBits <= 256) {
// 256-bit Elliptic Curve is roughly 128-bit strong, meaning SHA-256 is a good fit.
return Collections.singletonList(SignatureAlgorithm.ECDSA_WITH_SHA256);
} else {
// Keys longer than 256 bit need to be paired with a stronger digest to avoid the
// digest being the weak link. SHA-512 is the next strongest supported digest.
return Collections.singletonList(SignatureAlgorithm.ECDSA_WITH_SHA512);
}
} else {
throw new InvalidKeyException("Unsupported key algorithm: " + keyAlgorithm);
}
}
/**
* Signs the provided APK using APK Signature Scheme v2 and returns the APK Signing Block
* containing the signature.
*
* @param signerConfigs signer configurations, one for each signer At least one signer config
* must be provided.
*
* @throws IOException if an I/O error occurs
* @throws InvalidKeyException if a signing key is not suitable for this signature scheme or
* cannot be used in general
* @throws SignatureException if an error occurs when computing digests of generating
* signatures
*/
public static byte[] generateApkSigningBlock(
DataSource beforeCentralDir,
DataSource centralDir,
DataSource eocd,
List<SignerConfig> signerConfigs)
throws IOException, InvalidKeyException, SignatureException {
if (signerConfigs.isEmpty()) {
throw new IllegalArgumentException(
"No signer configs provided. At least one is required");
}
// Figure out which digest(s) to use for APK contents.
Set<ContentDigestAlgorithm> contentDigestAlgorithms = new HashSet<>(1);
for (SignerConfig signerConfig : signerConfigs) {
for (SignatureAlgorithm signatureAlgorithm : signerConfig.signatureAlgorithms) {
contentDigestAlgorithms.add(signatureAlgorithm.getContentDigestAlgorithm());
}
}
// Ensure that, when digesting, ZIP End of Central Directory record's Central Directory
// offset field is treated as pointing to the offset at which the APK Signing Block will
// start.
long centralDirOffsetForDigesting = beforeCentralDir.size();
ByteBuffer eocdBuf = copyToByteBuffer(eocd);
eocdBuf.order(ByteOrder.LITTLE_ENDIAN);
ZipUtils.setZipEocdCentralDirectoryOffset(eocdBuf, centralDirOffsetForDigesting);
// Compute digests of APK contents.
Map<ContentDigestAlgorithm, byte[]> contentDigests; // digest algorithm ID -> digest
try {
contentDigests =
computeContentDigests(
contentDigestAlgorithms,
new DataSource[] {
beforeCentralDir,
centralDir,
DataSources.asDataSource(eocdBuf)});
} catch (IOException e) {
throw new IOException("Failed to read APK being signed", e);
} catch (DigestException e) {
throw new SignatureException("Failed to compute digests of APK", e);
}
// Sign the digests and wrap the signatures and signer info into an APK Signing Block.
return generateApkSigningBlock(signerConfigs, contentDigests);
}
private static Map<ContentDigestAlgorithm, byte[]> computeContentDigests(
Set<ContentDigestAlgorithm> digestAlgorithms,
DataSource[] contents) throws IOException, DigestException {
// For each digest algorithm the result is computed as follows:
// 1. Each segment of contents is split into consecutive chunks of 1 MB in size.
// The final chunk will be shorter iff the length of segment is not a multiple of 1 MB.
// No chunks are produced for empty (zero length) segments.
// 2. The digest of each chunk is computed over the concatenation of byte 0xa5, the chunk's
// length in bytes (uint32 little-endian) and the chunk's contents.
// 3. The output digest is computed over the concatenation of the byte 0x5a, the number of
// chunks (uint32 little-endian) and the concatenation of digests of chunks of all
// segments in-order.
long chunkCountLong = 0;
for (DataSource input : contents) {
chunkCountLong +=
getChunkCount(input.size(), CONTENT_DIGESTED_CHUNK_MAX_SIZE_BYTES);
}
if (chunkCountLong > Integer.MAX_VALUE) {
throw new DigestException("Input too long: " + chunkCountLong + " chunks");
}
int chunkCount = (int) chunkCountLong;
ContentDigestAlgorithm[] digestAlgorithmsArray =
digestAlgorithms.toArray(new ContentDigestAlgorithm[digestAlgorithms.size()]);
MessageDigest[] mds = new MessageDigest[digestAlgorithmsArray.length];
byte[][] digestsOfChunks = new byte[digestAlgorithmsArray.length][];
int[] digestOutputSizes = new int[digestAlgorithmsArray.length];
for (int i = 0; i < digestAlgorithmsArray.length; i++) {
ContentDigestAlgorithm digestAlgorithm = digestAlgorithmsArray[i];
int digestOutputSizeBytes = digestAlgorithm.getChunkDigestOutputSizeBytes();
digestOutputSizes[i] = digestOutputSizeBytes;
byte[] concatenationOfChunkCountAndChunkDigests =
new byte[5 + chunkCount * digestOutputSizeBytes];
concatenationOfChunkCountAndChunkDigests[0] = 0x5a;
setUnsignedInt32LittleEndian(
chunkCount, concatenationOfChunkCountAndChunkDigests, 1);
digestsOfChunks[i] = concatenationOfChunkCountAndChunkDigests;
String jcaAlgorithm = digestAlgorithm.getJcaMessageDigestAlgorithm();
try {
mds[i] = MessageDigest.getInstance(jcaAlgorithm);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(jcaAlgorithm + " MessageDigest not supported", e);
}
}
MessageDigestSink mdSink = new MessageDigestSink(mds);
byte[] chunkContentPrefix = new byte[5];
chunkContentPrefix[0] = (byte) 0xa5;
int chunkIndex = 0;
// Optimization opportunity: digests of chunks can be computed in parallel. However,
// determining the number of computations to be performed in parallel is non-trivial. This
// depends on a wide range of factors, such as data source type (e.g., in-memory or fetched
// from file), CPU/memory/disk cache bandwidth and latency, interconnect architecture of CPU
// cores, load on the system from other threads of execution and other processes, size of
// input.
// For now, we compute these digests sequentially and thus have the luxury of improving
// performance by writing the digest of each chunk into a pre-allocated buffer at exactly
// the right position. This avoids unnecessary allocations, copying, and enables the final
// digest to be more efficient because it's presented with all of its input in one go.
for (DataSource input : contents) {
long inputOffset = 0;
long inputRemaining = input.size();
while (inputRemaining > 0) {
int chunkSize =
(int) Math.min(inputRemaining, CONTENT_DIGESTED_CHUNK_MAX_SIZE_BYTES);
setUnsignedInt32LittleEndian(chunkSize, chunkContentPrefix, 1);
for (int i = 0; i < mds.length; i++) {
mds[i].update(chunkContentPrefix);
}
try {
input.feed(inputOffset, chunkSize, mdSink);
} catch (IOException e) {
throw new IOException("Failed to read chunk #" + chunkIndex, e);
}
for (int i = 0; i < digestAlgorithmsArray.length; i++) {
MessageDigest md = mds[i];
byte[] concatenationOfChunkCountAndChunkDigests = digestsOfChunks[i];
int expectedDigestSizeBytes = digestOutputSizes[i];
int actualDigestSizeBytes =
md.digest(
concatenationOfChunkCountAndChunkDigests,
5 + chunkIndex * expectedDigestSizeBytes,
expectedDigestSizeBytes);
if (actualDigestSizeBytes != expectedDigestSizeBytes) {
throw new RuntimeException(
"Unexpected output size of " + md.getAlgorithm()
+ " digest: " + actualDigestSizeBytes);
}
}
inputOffset += chunkSize;
inputRemaining -= chunkSize;
chunkIndex++;
}
}
Map<ContentDigestAlgorithm, byte[]> result = new HashMap<>(digestAlgorithmsArray.length);
for (int i = 0; i < digestAlgorithmsArray.length; i++) {
ContentDigestAlgorithm digestAlgorithm = digestAlgorithmsArray[i];
byte[] concatenationOfChunkCountAndChunkDigests = digestsOfChunks[i];
MessageDigest md = mds[i];
byte[] digest = md.digest(concatenationOfChunkCountAndChunkDigests);
result.put(digestAlgorithm, digest);
}
return result;
}
private static final long getChunkCount(long inputSize, int chunkSize) {
return (inputSize + chunkSize - 1) / chunkSize;
}
private static void setUnsignedInt32LittleEndian(int value, byte[] result, int offset) {
result[offset] = (byte) (value & 0xff);
result[offset + 1] = (byte) ((value >> 8) & 0xff);
result[offset + 2] = (byte) ((value >> 16) & 0xff);
result[offset + 3] = (byte) ((value >> 24) & 0xff);
}
private static byte[] generateApkSigningBlock(
List<SignerConfig> signerConfigs,
Map<ContentDigestAlgorithm, byte[]> contentDigests)
throws InvalidKeyException, SignatureException {
byte[] apkSignatureSchemeV2Block =
generateApkSignatureSchemeV2Block(signerConfigs, contentDigests);
return generateApkSigningBlock(apkSignatureSchemeV2Block);
}
private static byte[] generateApkSigningBlock(byte[] apkSignatureSchemeV2Block) {
// FORMAT:
// uint64: size (excluding this field)
// repeated ID-value pairs:
// uint64: size (excluding this field)
// uint32: ID
// (size - 4) bytes: value
// uint64: size (same as the one above)
// uint128: magic
int resultSize =
8 // size
+ 8 + 4 + apkSignatureSchemeV2Block.length // v2Block as ID-value pair
+ 8 // size
+ 16 // magic
;
ByteBuffer result = ByteBuffer.allocate(resultSize);
result.order(ByteOrder.LITTLE_ENDIAN);
long blockSizeFieldValue = resultSize - 8;
result.putLong(blockSizeFieldValue);
long pairSizeFieldValue = 4 + apkSignatureSchemeV2Block.length;
result.putLong(pairSizeFieldValue);
result.putInt(APK_SIGNATURE_SCHEME_V2_BLOCK_ID);
result.put(apkSignatureSchemeV2Block);
result.putLong(blockSizeFieldValue);
result.put(APK_SIGNING_BLOCK_MAGIC);
return result.array();
}
private static byte[] generateApkSignatureSchemeV2Block(
List<SignerConfig> signerConfigs,
Map<ContentDigestAlgorithm, byte[]> contentDigests)
throws InvalidKeyException, SignatureException {
// FORMAT:
// * length-prefixed sequence of length-prefixed signer blocks.
List<byte[]> signerBlocks = new ArrayList<>(signerConfigs.size());
int signerNumber = 0;
for (SignerConfig signerConfig : signerConfigs) {
signerNumber++;
byte[] signerBlock;
try {
signerBlock = generateSignerBlock(signerConfig, contentDigests);
} catch (InvalidKeyException e) {
throw new InvalidKeyException("Signer #" + signerNumber + " failed", e);
} catch (SignatureException e) {
throw new SignatureException("Signer #" + signerNumber + " failed", e);
}
signerBlocks.add(signerBlock);
}
return encodeAsSequenceOfLengthPrefixedElements(
new byte[][] {
encodeAsSequenceOfLengthPrefixedElements(signerBlocks),
});
}
private static byte[] generateSignerBlock(
SignerConfig signerConfig,
Map<ContentDigestAlgorithm, byte[]> contentDigests)
throws InvalidKeyException, SignatureException {
if (signerConfig.certificates.isEmpty()) {
throw new SignatureException("No certificates configured for signer");
}
PublicKey publicKey = signerConfig.certificates.get(0).getPublicKey();
byte[] encodedPublicKey = encodePublicKey(publicKey);
V2SignatureSchemeBlock.SignedData signedData = new V2SignatureSchemeBlock.SignedData();
try {
signedData.certificates = encodeCertificates(signerConfig.certificates);
} catch (CertificateEncodingException e) {
throw new SignatureException("Failed to encode certificates", e);
}
List<Pair<Integer, byte[]>> digests =
new ArrayList<>(signerConfig.signatureAlgorithms.size());
for (SignatureAlgorithm signatureAlgorithm : signerConfig.signatureAlgorithms) {
ContentDigestAlgorithm contentDigestAlgorithm =
signatureAlgorithm.getContentDigestAlgorithm();
byte[] contentDigest = contentDigests.get(contentDigestAlgorithm);
if (contentDigest == null) {
throw new RuntimeException(
contentDigestAlgorithm + " content digest for " + signatureAlgorithm
+ " not computed");
}
digests.add(Pair.of(signatureAlgorithm.getId(), contentDigest));
}
signedData.digests = digests;
V2SignatureSchemeBlock.Signer signer = new V2SignatureSchemeBlock.Signer();
// FORMAT:
// * length-prefixed sequence of length-prefixed digests:
// * uint32: signature algorithm ID
// * length-prefixed bytes: digest of contents
// * length-prefixed sequence of certificates:
// * length-prefixed bytes: X.509 certificate (ASN.1 DER encoded).
// * length-prefixed sequence of length-prefixed additional attributes:
// * uint32: ID
// * (length - 4) bytes: value
signer.signedData = encodeAsSequenceOfLengthPrefixedElements(new byte[][] {
encodeAsSequenceOfLengthPrefixedPairsOfIntAndLengthPrefixedBytes(signedData.digests),
encodeAsSequenceOfLengthPrefixedElements(signedData.certificates),
// additional attributes
new byte[0],
});
signer.publicKey = encodedPublicKey;
signer.signatures = new ArrayList<>(signerConfig.signatureAlgorithms.size());
for (SignatureAlgorithm signatureAlgorithm : signerConfig.signatureAlgorithms) {
Pair<String, ? extends AlgorithmParameterSpec> sigAlgAndParams =
signatureAlgorithm.getJcaSignatureAlgorithmAndParams();
String jcaSignatureAlgorithm = sigAlgAndParams.getFirst();
AlgorithmParameterSpec jcaSignatureAlgorithmParams = sigAlgAndParams.getSecond();
byte[] signatureBytes;
try {
Signature signature = Signature.getInstance(jcaSignatureAlgorithm);
signature.initSign(signerConfig.privateKey);
if (jcaSignatureAlgorithmParams != null) {
signature.setParameter(jcaSignatureAlgorithmParams);
}
signature.update(signer.signedData);
signatureBytes = signature.sign();
} catch (InvalidKeyException e) {
throw new InvalidKeyException("Failed sign using " + jcaSignatureAlgorithm, e);
} catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException
| SignatureException e) {
throw new SignatureException("Failed sign using " + jcaSignatureAlgorithm, e);
}
try {
Signature signature = Signature.getInstance(jcaSignatureAlgorithm);
signature.initVerify(publicKey);
if (jcaSignatureAlgorithmParams != null) {
signature.setParameter(jcaSignatureAlgorithmParams);
}
signature.update(signer.signedData);
if (!signature.verify(signatureBytes)) {
throw new SignatureException("Signature did not verify");
}
} catch (InvalidKeyException e) {
throw new InvalidKeyException("Failed to verify generated " + jcaSignatureAlgorithm
+ " signature using public key from certificate", e);
} catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException
| SignatureException e) {
throw new SignatureException("Failed to verify generated " + jcaSignatureAlgorithm
+ " signature using public key from certificate", e);
}
signer.signatures.add(Pair.of(signatureAlgorithm.getId(), signatureBytes));
}
// FORMAT:
// * length-prefixed signed data
// * length-prefixed sequence of length-prefixed signatures:
// * uint32: signature algorithm ID
// * length-prefixed bytes: signature of signed data
// * length-prefixed bytes: public key (X.509 SubjectPublicKeyInfo, ASN.1 DER encoded)
return encodeAsSequenceOfLengthPrefixedElements(
new byte[][] {
signer.signedData,
encodeAsSequenceOfLengthPrefixedPairsOfIntAndLengthPrefixedBytes(
signer.signatures),
signer.publicKey,
});
}
private static final class V2SignatureSchemeBlock {
private static final class Signer {
public byte[] signedData;
public List<Pair<Integer, byte[]>> signatures;
public byte[] publicKey;
}
private static final class SignedData {
public List<Pair<Integer, byte[]>> digests;
public List<byte[]> certificates;
}
}
private static byte[] encodePublicKey(PublicKey publicKey) throws InvalidKeyException {
byte[] encodedPublicKey = null;
if ("X.509".equals(publicKey.getFormat())) {
encodedPublicKey = publicKey.getEncoded();
}
if (encodedPublicKey == null) {
try {
encodedPublicKey =
KeyFactory.getInstance(publicKey.getAlgorithm())
.getKeySpec(publicKey, X509EncodedKeySpec.class)
.getEncoded();
} catch (NoSuchAlgorithmException e) {
throw new InvalidKeyException(
"Failed to obtain X.509 encoded form of public key " + publicKey
+ " of class " + publicKey.getClass().getName(),
e);
} catch (InvalidKeySpecException e) {
throw new InvalidKeyException(
"Failed to obtain X.509 encoded form of public key " + publicKey
+ " of class " + publicKey.getClass().getName(),
e);
}
}
if ((encodedPublicKey == null) || (encodedPublicKey.length == 0)) {
throw new InvalidKeyException(
"Failed to obtain X.509 encoded form of public key " + publicKey
+ " of class " + publicKey.getClass().getName());
}
return encodedPublicKey;
}
private static List<byte[]> encodeCertificates(List<X509Certificate> certificates)
throws CertificateEncodingException {
List<byte[]> result = new ArrayList<>(certificates.size());
for (X509Certificate certificate : certificates) {
result.add(certificate.getEncoded());
}
return result;
}
private static byte[] encodeAsSequenceOfLengthPrefixedElements(List<byte[]> sequence) {
return encodeAsSequenceOfLengthPrefixedElements(
sequence.toArray(new byte[sequence.size()][]));
}
private static byte[] encodeAsSequenceOfLengthPrefixedElements(byte[][] sequence) {
int payloadSize = 0;
for (byte[] element : sequence) {
payloadSize += 4 + element.length;
}
ByteBuffer result = ByteBuffer.allocate(payloadSize);
result.order(ByteOrder.LITTLE_ENDIAN);
for (byte[] element : sequence) {
result.putInt(element.length);
result.put(element);
}
return result.array();
}
private static byte[] encodeAsSequenceOfLengthPrefixedPairsOfIntAndLengthPrefixedBytes(
List<Pair<Integer, byte[]>> sequence) {
int resultSize = 0;
for (Pair<Integer, byte[]> element : sequence) {
resultSize += 12 + element.getSecond().length;
}
ByteBuffer result = ByteBuffer.allocate(resultSize);
result.order(ByteOrder.LITTLE_ENDIAN);
for (Pair<Integer, byte[]> element : sequence) {
byte[] second = element.getSecond();
result.putInt(8 + second.length);
result.putInt(element.getFirst());
result.putInt(second.length);
result.put(second);
}
return result.array();
}
private static ByteBuffer copyToByteBuffer(DataSource dataSource) throws IOException {
long dataSourceSize = dataSource.size();
if (dataSourceSize > Integer.MAX_VALUE) {
throw new IllegalArgumentException("Data source too large: " + dataSourceSize);
}
ByteBuffer result = ByteBuffer.allocate((int) dataSourceSize);
dataSource.feed(0, result.remaining(), new ByteBufferSink(result));
result.position(0);
return result;
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.util;
import com.android.apksigner.core.util.DataSink;
import com.android.apksigner.core.util.DataSource;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* {@link DataSource} backed by a {@link ByteBuffer}.
*/
public class ByteBufferDataSource implements DataSource {
private final ByteBuffer mBuffer;
private final long mSize;
/**
* Constructs a new {@code ByteBufferDigestSource} based on the data contained in the provided
* buffer between the buffer's position and limit.
*/
public ByteBufferDataSource(ByteBuffer buffer) {
mBuffer = buffer.slice();
mSize = buffer.remaining();
}
@Override
public long size() {
return mSize;
}
@Override
public void feed(long offset, int size, DataSink sink) throws IOException {
if (offset < 0) {
throw new IllegalArgumentException("offset: " + offset);
}
if (size < 0) {
throw new IllegalArgumentException("size: " + size);
}
if (offset > mSize) {
throw new IllegalArgumentException(
"offset (" + offset + ") > source size (" + mSize + ")");
}
long endOffset = offset + size;
if (endOffset < offset) {
throw new IllegalArgumentException(
"offset (" + offset + ") + size (" + size + ") overflow");
}
if (endOffset > mSize) {
throw new IllegalArgumentException(
"offset (" + offset + ") + size (" + size + ") > source size (" + mSize +")");
}
int chunkPosition = (int) offset; // safe to downcast because mSize <= Integer.MAX_VALUE
int chunkLimit = (int) endOffset; // safe to downcast because mSize <= Integer.MAX_VALUE
ByteBuffer chunk;
// Creating a slice of ByteBuffer modifies the state of the source ByteBuffer (position
// and limit fields, to be more specific). We thus use synchronization around these
// state-changing operations to make instances of this class thread-safe.
synchronized (mBuffer) {
// ByteBuffer.limit(int) and .position(int) check that that the position >= limit
// invariant is not broken. Thus, the only way to safely change position and limit
// without caring about their current values is to first set position to 0 or set the
// limit to capacity.
mBuffer.position(0);
mBuffer.limit(chunkLimit);
mBuffer.position(chunkPosition);
chunk = mBuffer.slice();
}
sink.consume(chunk);
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.util;
import com.android.apksigner.core.util.DataSink;
import java.io.IOException;
import java.nio.BufferOverflowException;
import java.nio.ByteBuffer;
/**
* Data sink which stores all received data into the associated {@link ByteBuffer}.
*/
public class ByteBufferSink implements DataSink {
private final ByteBuffer mBuffer;
public ByteBufferSink(ByteBuffer buffer) {
mBuffer = buffer;
}
@Override
public void consume(byte[] buf, int offset, int length) throws IOException {
try {
mBuffer.put(buf, offset, length);
} catch (BufferOverflowException e) {
throw new IOException(
"Insufficient space in output buffer for " + length + " bytes", e);
}
}
@Override
public void consume(ByteBuffer buf) throws IOException {
int length = buf.remaining();
try {
mBuffer.put(buf);
} catch (BufferOverflowException e) {
throw new IOException(
"Insufficient space in output buffer for " + length + " bytes", e);
}
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.internal.zip;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
/**
* Assorted ZIP format helpers.
*
* <p>NOTE: Most helper methods operating on {@code ByteBuffer} instances expect that the byte
* order of these buffers is little-endian.
*/
public abstract class ZipUtils {
private ZipUtils() {}
private static final int ZIP_EOCD_CENTRAL_DIR_OFFSET_FIELD_OFFSET = 16;
/**
* Sets the offset of the start of the ZIP Central Directory in the archive.
*
* <p>NOTE: Byte order of {@code zipEndOfCentralDirectory} must be little-endian.
*/
public static void setZipEocdCentralDirectoryOffset(
ByteBuffer zipEndOfCentralDirectory, long offset) {
assertByteOrderLittleEndian(zipEndOfCentralDirectory);
setUnsignedInt32(
zipEndOfCentralDirectory,
zipEndOfCentralDirectory.position() + ZIP_EOCD_CENTRAL_DIR_OFFSET_FIELD_OFFSET,
offset);
}
private static void assertByteOrderLittleEndian(ByteBuffer buffer) {
if (buffer.order() != ByteOrder.LITTLE_ENDIAN) {
throw new IllegalArgumentException("ByteBuffer byte order must be little endian");
}
}
private static void setUnsignedInt32(ByteBuffer buffer, int offset, long value) {
if ((value < 0) || (value > 0xffffffffL)) {
throw new IllegalArgumentException("uint32 value of out range: " + value);
}
buffer.putInt(buffer.position() + offset, (int) value);
}
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.util;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* Consumer of input data which may be provided in one go or in chunks.
*/
public interface DataSink {
/**
* Consumes the provided chunk of data.
*
* <p>This data sink guarantees to not hold references to the provided buffer after this method
* terminates.
*/
void consume(byte[] buf, int offset, int length) throws IOException;
/**
* Consumes all remaining data in the provided buffer and advances the buffer's position
* to the buffer's limit.
*
* <p>This data sink guarantees to not hold references to the provided buffer after this method
* terminates.
*/
void consume(ByteBuffer buf) throws IOException;
}

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.apksigner.core.util;
import java.io.IOException;
/**
* Abstract representation of a source of data.
*
* <p>This abstraction serves three purposes:
* <ul>
* <li>Transparent handling of different types of sources, such as {@code byte[]},
* {@link java.nio.ByteBuffer}, {@link java.io.RandomAccessFile}, memory-mapped file.</li>
* <li>Support sources larger than 2 GB. If all sources were smaller than 2 GB, {@code ByteBuffer}
* may have worked as the unifying abstraction.</li>
* <li>Support sources which do not fit into logical memory as a contiguous region.</li>
* </ul>
*/
public interface DataSource {
/**
* Returns the amount of data (in bytes) contained in this data source.
*/
long size();
/**
* Feeds the specified chunk from this data source into the provided sink.
*
* @param offset index (in bytes) at which the chunk starts inside data source
* @param size size (in bytes) of the chunk
*/
void feed(long offset, int size, DataSink sink) throws IOException;
}

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package com.android.apksigner.core.util;
import com.android.apksigner.core.internal.util.ByteBufferDataSource;
import java.nio.ByteBuffer;
/**
* Utility methods for working with {@link DataSource} abstraction.
*/
public abstract class DataSources {
private DataSources() {}
/**
* Returns a {@link DataSource} backed by the provided {@link ByteBuffer}. The data source
* represents the data contained between the position and limit of the buffer.
*/
public static DataSource asDataSource(ByteBuffer buffer) {
if (buffer == null) {
throw new NullPointerException();
}
return new ByteBufferDataSource(buffer);
}
}