Add initial support for appending signatures to an APK am: b22ac09e78
Original change: https://googleplex-android-review.googlesource.com/c/platform/tools/apksig/+/14708776
Change-Id: I76312c6b04ae64bbcd4dc9571295111c3d77552d
diff --git a/src/apksigner/java/com/android/apksigner/ApkSignerTool.java b/src/apksigner/java/com/android/apksigner/ApkSignerTool.java
index 6bc00d2..9fd0c34 100644
--- a/src/apksigner/java/com/android/apksigner/ApkSignerTool.java
+++ b/src/apksigner/java/com/android/apksigner/ApkSignerTool.java
@@ -160,6 +160,7 @@
boolean v4SigningFlagFound = false;
boolean sourceStampFlagFound = false;
boolean deterministicDsaSigning = false;
+ boolean otherSignersSignaturesPreserved = false;
while ((optionName = optionsParser.nextOption()) != null) {
optionOriginalForm = optionsParser.getOptionOriginalForm();
if (("help".equals(optionName)) || ("h".equals(optionName))) {
@@ -262,6 +263,8 @@
sourceStampLineage = getLineageFromInputFile(stampLineageFile);
} else if ("deterministic-dsa-signing".equals(optionName)) {
deterministicDsaSigning = optionsParser.getOptionalBooleanValue(false);
+ } else if ("append-signature".equals(optionName)) {
+ otherSignersSignaturesPreserved = optionsParser.getOptionalBooleanValue(true);
} else {
throw new ParameterException(
"Unsupported option: " + optionOriginalForm + ". See --help for supported"
@@ -350,7 +353,7 @@
new ApkSigner.Builder(signerConfigs)
.setInputApk(inputApk)
.setOutputApk(tmpOutputApk)
- .setOtherSignersSignaturesPreserved(false)
+ .setOtherSignersSignaturesPreserved(otherSignersSignaturesPreserved)
.setV1SigningEnabled(v1SigningEnabled)
.setV2SigningEnabled(v2SigningEnabled)
.setV3SigningEnabled(v3SigningEnabled)
diff --git a/src/apksigner/java/com/android/apksigner/help_sign.txt b/src/apksigner/java/com/android/apksigner/help_sign.txt
index 88c27a1..d66b7a3 100644
--- a/src/apksigner/java/com/android/apksigner/help_sign.txt
+++ b/src/apksigner/java/com/android/apksigner/help_sign.txt
@@ -94,6 +94,14 @@
whether to use the deterministic version as specified in
RFC 6979.
+--append-signature Appends the current signature to any signatures that
+ already exist within the APK. This option can be used
+ when an APK is signed by multiple independent signers to
+ allow each to add their own signature without needing to
+ share their private key. This option can also be used to
+ preserve existing key / value blocks that exist within the
+ APK signing block.
+
-h, --help Show help about this command and exit
diff --git a/src/main/java/com/android/apksig/DefaultApkSignerEngine.java b/src/main/java/com/android/apksig/DefaultApkSignerEngine.java
index c108191..e2256da 100644
--- a/src/main/java/com/android/apksig/DefaultApkSignerEngine.java
+++ b/src/main/java/com/android/apksig/DefaultApkSignerEngine.java
@@ -18,6 +18,7 @@
import static com.android.apksig.apk.ApkUtils.SOURCE_STAMP_CERTIFICATE_HASH_ZIP_ENTRY_NAME;
import static com.android.apksig.apk.ApkUtils.computeSha256DigestBytes;
+import static com.android.apksig.internal.apk.ApkSigningBlockUtils.VERITY_PADDING_BLOCK_ID;
import static com.android.apksig.internal.apk.ApkSigningBlockUtils.VERSION_APK_SIGNATURE_SCHEME_V2;
import static com.android.apksig.internal.apk.ApkSigningBlockUtils.VERSION_APK_SIGNATURE_SCHEME_V3;
import static com.android.apksig.internal.apk.ApkSigningBlockUtils.VERSION_JAR_SIGNATURE_SCHEME;
@@ -64,6 +65,7 @@
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
+import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
@@ -103,6 +105,9 @@
private final int mMinSdkVersion;
private final SigningCertificateLineage mSigningCertificateLineage;
+ private List<byte[]> mPreservedV2Signers = Collections.emptyList();
+ private List<Pair<byte[], Integer>> mPreservedSignatureBlocks = Collections.emptyList();
+
private List<V1SchemeSigner.SignerConfig> mV1SignerConfigs = Collections.emptyList();
private DigestAlgorithm mV1ContentDigestAlgorithm;
@@ -159,6 +164,21 @@
private RunnablesExecutor mExecutor = RunnablesExecutor.MULTI_THREADED;
+ /**
+ * A Set of block IDs to be discarded when requesting to preserve the original signatures.
+ */
+ private static final Set<Integer> DISCARDED_SIGNATURE_BLOCK_IDS;
+ static {
+ DISCARDED_SIGNATURE_BLOCK_IDS = new HashSet<>(3);
+ // The verity padding block is recomputed on an
+ // ApkSigningBlockUtils.ANDROID_COMMON_PAGE_ALIGNMENT_BYTES boundary.
+ DISCARDED_SIGNATURE_BLOCK_IDS.add(VERITY_PADDING_BLOCK_ID);
+ // The source stamp block is not currently preserved; appending a new signature scheme
+ // block will invalidate the previous source stamp.
+ DISCARDED_SIGNATURE_BLOCK_IDS.add(Constants.V1_SOURCE_STAMP_BLOCK_ID);
+ DISCARDED_SIGNATURE_BLOCK_IDS.add(Constants.V2_SOURCE_STAMP_BLOCK_ID);
+ }
+
private DefaultApkSignerEngine(
List<SignerConfig> signerConfigs,
SignerConfig sourceStampSignerConfig,
@@ -176,10 +196,6 @@
if (signerConfigs.isEmpty()) {
throw new IllegalArgumentException("At least one signer config must be provided");
}
- if (otherSignersSignaturesPreserved) {
- throw new UnsupportedOperationException(
- "Preserving other signer's signatures is not yet implemented");
- }
mV1SigningEnabled = v1SigningEnabled;
mV2SigningEnabled = v2SigningEnabled;
@@ -547,11 +563,92 @@
}
if (mOtherSignersSignaturesPreserved) {
- // TODO: Preserve blocks other than APK Signature Scheme v2 blocks of signers configured
- // in this engine.
+ boolean schemeSignatureBlockPreserved = false;
+ mPreservedSignatureBlocks = new ArrayList<>();
+ try {
+ List<Pair<byte[], Integer>> signatureBlocks =
+ ApkSigningBlockUtils.getApkSignatureBlocks(apkSigningBlock);
+ for (Pair<byte[], Integer> signatureBlock : signatureBlocks) {
+ if (signatureBlock.getSecond() == Constants.APK_SIGNATURE_SCHEME_V2_BLOCK_ID) {
+ // If a V2 signature block is found and the engine is configured to use V2
+ // then save any of the previous signers that are not part of the current
+ // signing request.
+ if (mV2SigningEnabled) {
+ List<Pair<List<X509Certificate>, byte[]>> v2Signers =
+ ApkSigningBlockUtils.getApkSignatureBlockSigners(
+ signatureBlock.getFirst());
+ mPreservedV2Signers = new ArrayList<>(v2Signers.size());
+ for (Pair<List<X509Certificate>, byte[]> v2Signer : v2Signers) {
+ if (!isConfiguredWithSigner(v2Signer.getFirst())) {
+ mPreservedV2Signers.add(v2Signer.getSecond());
+ schemeSignatureBlockPreserved = true;
+ }
+ }
+ } else {
+ // else V2 signing is not enabled; save the entire signature block to be
+ // added to the final APK signing block.
+ mPreservedSignatureBlocks.add(signatureBlock);
+ schemeSignatureBlockPreserved = true;
+ }
+ } else if (signatureBlock.getSecond()
+ == Constants.APK_SIGNATURE_SCHEME_V3_BLOCK_ID) {
+ // Preserving other signers in the presence of a V3 signature block is only
+ // supported if the engine is configured to resign the APK with the V3
+ // signature scheme, and the V3 signer in the signature block is the same
+ // as the engine is configured to use.
+ if (!mV3SigningEnabled) {
+ throw new IllegalStateException(
+ "Preserving an existing V3 signature is not supported");
+ }
+ List<Pair<List<X509Certificate>, byte[]>> v3Signers =
+ ApkSigningBlockUtils.getApkSignatureBlockSigners(
+ signatureBlock.getFirst());
+ if (v3Signers.size() > 1) {
+ throw new IllegalArgumentException(
+ "The provided APK signing block contains " + v3Signers.size()
+ + " V3 signers; the V3 signature scheme only supports"
+ + " one signer");
+ }
+ // If there is only a single V3 signer then ensure it is the signer
+ // configured to sign the APK.
+ if (v3Signers.size() == 1
+ && !isConfiguredWithSigner(v3Signers.get(0).getFirst())) {
+ throw new IllegalStateException(
+ "The V3 signature scheme only supports one signer; a request "
+ + "was made to preserve the existing V3 signature, "
+ + "but the engine is configured to sign with a "
+ + "different signer");
+ }
+ } else if (!DISCARDED_SIGNATURE_BLOCK_IDS.contains(
+ signatureBlock.getSecond())) {
+ mPreservedSignatureBlocks.add(signatureBlock);
+ }
+ }
+ } catch (ApkFormatException | CertificateException | IOException e) {
+ throw new IllegalArgumentException("Unable to parse the provided signing block", e);
+ }
+ // Signature scheme V3+ only support a single signer; if the engine is configured to
+ // sign with V3+ then ensure no scheme signature blocks have been preserved.
+ if (mV3SigningEnabled && schemeSignatureBlockPreserved) {
+ throw new IllegalStateException(
+ "Signature scheme V3+ only supports a single signer and cannot be "
+ + "appended to the existing signature scheme blocks");
+ }
return;
}
- // TODO: Preserve blocks other than APK Signature Scheme v2 blocks.
+ }
+
+ /**
+ * Returns whether the engine is configured to sign the APK with a signer using the specified
+ * {@code signerCerts}.
+ */
+ private boolean isConfiguredWithSigner(List<X509Certificate> signerCerts) {
+ for (SignerConfig signerConfig : mSignerConfigs) {
+ if (signerCerts.containsAll(signerConfig.getCertificates())) {
+ return true;
+ }
+ }
+ return false;
}
@Override
@@ -868,6 +965,13 @@
List<Pair<byte[], Integer>> signingSchemeBlocks = new ArrayList<>();
ApkSigningBlockUtils.SigningSchemeBlockAndDigests v2SigningSchemeBlockAndDigests = null;
ApkSigningBlockUtils.SigningSchemeBlockAndDigests v3SigningSchemeBlockAndDigests = null;
+ // If the engine is configured to preserve previous signature blocks and any were found in
+ // the existing APK signing block then add them to the list to be used to generate the
+ // new APK signing block.
+ if (mOtherSignersSignaturesPreserved && mPreservedSignatureBlocks != null
+ && !mPreservedSignatureBlocks.isEmpty()) {
+ signingSchemeBlocks.addAll(mPreservedSignatureBlocks);
+ }
// create APK Signature Scheme V2 Signature if requested
if (mV2SigningEnabled) {
@@ -881,7 +985,8 @@
zipCentralDirectory,
eocd,
v2SignerConfigs,
- mV3SigningEnabled);
+ mV3SigningEnabled,
+ mOtherSignersSignaturesPreserved ? mPreservedV2Signers : null);
signingSchemeBlocks.add(v2SigningSchemeBlockAndDigests.signingSchemeBlock);
}
if (mV3SigningEnabled) {
diff --git a/src/main/java/com/android/apksig/apk/ApkUtils.java b/src/main/java/com/android/apksig/apk/ApkUtils.java
index 69399a7..426f0be 100644
--- a/src/main/java/com/android/apksig/apk/ApkUtils.java
+++ b/src/main/java/com/android/apksig/apk/ApkUtils.java
@@ -97,6 +97,27 @@
}
/**
+ * Returns the APK Signing Block of the provided {@code apk}.
+ *
+ * @throws ApkFormatException if the APK is not a valid ZIP archive
+ * @throws IOException if an I/O error occurs
+ * @throws ApkSigningBlockNotFoundException if there is no APK Signing Block in the APK
+ *
+ * @see <a href="https://source.android.com/security/apksigning/v2.html">APK Signature Scheme v2
+ * </a>
+ */
+ public static ApkSigningBlock findApkSigningBlock(DataSource apk)
+ throws ApkFormatException, IOException, ApkSigningBlockNotFoundException {
+ ApkUtils.ZipSections inputZipSections;
+ try {
+ inputZipSections = ApkUtils.findZipSections(apk);
+ } catch (ZipFormatException e) {
+ throw new ApkFormatException("Malformed APK: not a ZIP archive", e);
+ }
+ return findApkSigningBlock(apk, inputZipSections);
+ }
+
+ /**
* Returns the APK Signing Block of the provided APK.
*
* @throws IOException if an I/O error occurs
diff --git a/src/main/java/com/android/apksig/internal/apk/ApkSigningBlockUtils.java b/src/main/java/com/android/apksig/internal/apk/ApkSigningBlockUtils.java
index b91ccd8..61b7b00 100644
--- a/src/main/java/com/android/apksig/internal/apk/ApkSigningBlockUtils.java
+++ b/src/main/java/com/android/apksig/internal/apk/ApkSigningBlockUtils.java
@@ -39,8 +39,10 @@
import com.android.apksig.internal.pkcs7.SignerInfo;
import com.android.apksig.internal.util.ByteBufferDataSource;
import com.android.apksig.internal.util.ChainedDataSource;
+import com.android.apksig.internal.util.GuaranteedEncodedFormX509Certificate;
import com.android.apksig.internal.util.Pair;
import com.android.apksig.internal.util.VerityTreeBuilder;
+import com.android.apksig.internal.util.X509CertificateUtils;
import com.android.apksig.internal.x509.RSAPublicKey;
import com.android.apksig.internal.x509.SubjectPublicKeyInfo;
import com.android.apksig.internal.zip.ZipUtils;
@@ -65,6 +67,7 @@
import java.security.Signature;
import java.security.SignatureException;
import java.security.cert.CertificateEncodingException;
+import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidKeySpecException;
@@ -91,7 +94,7 @@
0x41, 0x50, 0x4b, 0x20, 0x53, 0x69, 0x67, 0x20,
0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x20, 0x34, 0x32,
};
- private static final int VERITY_PADDING_BLOCK_ID = 0x42726577;
+ public static final int VERITY_PADDING_BLOCK_ID = 0x42726577;
private static final ContentDigestAlgorithm[] V4_CONTENT_DIGEST_ALGORITHMS =
{CHUNKED_SHA512, VERITY_CHUNKED_SHA256, CHUNKED_SHA256};
@@ -843,7 +846,7 @@
// uint64: size (excluding this field)
// uint32: ID
// (size - 4) bytes: value
- // (extra placeholder ID-value for padding to make block size a multiple of 4096 bytes)
+ // (extra verity ID-value for padding to make block size a multiple of 4096 bytes)
// uint64: size (same as the one above)
// uint128: magic
@@ -877,7 +880,6 @@
long blockSizeFieldValue = resultSize - 8L;
result.putLong(blockSizeFieldValue);
-
for (Pair<byte[], Integer> schemeBlockPair : apkSignatureSchemeBlockPairs) {
byte[] apkSignatureSchemeBlock = schemeBlockPair.getFirst();
int apkSignatureSchemeId = schemeBlockPair.getSecond();
@@ -898,6 +900,116 @@
}
/**
+ * Returns the individual APK signature blocks within the provided {@code apkSigningBlock} in a
+ * {@code List} of {@code Pair} instances where the first element in the {@code Pair} is the
+ * contents / value of the signature block and the second element is the ID of the block.
+ *
+ * @throws IOException if an error is encountered reading the provided {@code apkSigningBlock}
+ */
+ public static List<Pair<byte[], Integer>> getApkSignatureBlocks(
+ DataSource apkSigningBlock) throws IOException {
+ // FORMAT:
+ // uint64: size (excluding this field)
+ // repeated ID-value pairs:
+ // uint64: size (excluding this field)
+ // uint32: ID
+ // (size - 4) bytes: value
+ // (extra verity ID-value for padding to make block size a multiple of 4096 bytes)
+ // uint64: size (same as the one above)
+ // uint128: magic
+ long apkSigningBlockSize = apkSigningBlock.size();
+ if (apkSigningBlock.size() > Integer.MAX_VALUE || apkSigningBlockSize < 32) {
+ throw new IllegalArgumentException(
+ "APK signing block size out of range: " + apkSigningBlockSize);
+ }
+ // Remove the header and footer from the signing block to iterate over only the repeated
+ // ID-value pairs.
+ ByteBuffer apkSigningBlockBuffer = apkSigningBlock.getByteBuffer(8,
+ (int) apkSigningBlock.size() - 32);
+ apkSigningBlockBuffer.order(ByteOrder.LITTLE_ENDIAN);
+ List<Pair<byte[], Integer>> signatureBlocks = new ArrayList<>();
+ while (apkSigningBlockBuffer.hasRemaining()) {
+ long blockLength = apkSigningBlockBuffer.getLong();
+ if (blockLength > Integer.MAX_VALUE || blockLength < 4) {
+ throw new IllegalArgumentException(
+ "Block index " + (signatureBlocks.size() + 1) + " size out of range: "
+ + blockLength);
+ }
+ int blockId = apkSigningBlockBuffer.getInt();
+ // Since the block ID has already been read from the signature block read the next
+ // blockLength - 4 bytes as the value.
+ byte[] blockValue = new byte[(int) blockLength - 4];
+ apkSigningBlockBuffer.get(blockValue);
+ signatureBlocks.add(Pair.of(blockValue, blockId));
+ }
+ return signatureBlocks;
+ }
+
+ /**
+ * Returns the individual APK signers within the provided {@code signatureBlock} in a {@code
+ * List} of {@code Pair} instances where the first element is a {@code List} of {@link
+ * X509Certificate}s and the second element is a byte array of the individual signer's block.
+ *
+ * <p>This method supports any signature block that adheres to the following format up to the
+ * signing certificate(s):
+ * <pre>
+ * * length-prefixed sequence of length-prefixed signers
+ * * length-prefixed signed data
+ * * 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).
+ * </pre>
+ *
+ * <p>Note, this is a convenience method to obtain any signers from an existing signature block;
+ * the signature of each signer will not be verified.
+ *
+ * @throws ApkFormatException if an error is encountered while parsing the provided {@code
+ * signatureBlock}
+ * @throws CertificateException if the signing certificate(s) within an individual signer block
+ * cannot be parsed
+ */
+ public static List<Pair<List<X509Certificate>, byte[]>> getApkSignatureBlockSigners(
+ byte[] signatureBlock) throws ApkFormatException, CertificateException {
+ ByteBuffer signatureBlockBuffer = ByteBuffer.wrap(signatureBlock);
+ signatureBlockBuffer.order(ByteOrder.LITTLE_ENDIAN);
+ ByteBuffer signersBuffer = getLengthPrefixedSlice(signatureBlockBuffer);
+ List<Pair<List<X509Certificate>, byte[]>> signers = new ArrayList<>();
+ while (signersBuffer.hasRemaining()) {
+ // Parse the next signer block, save all of its bytes for the resulting List, and
+ // rewind the buffer to allow the signing certificate(s) to be parsed.
+ ByteBuffer signer = getLengthPrefixedSlice(signersBuffer);
+ byte[] signerBytes = new byte[signer.remaining()];
+ signer.get(signerBytes);
+ signer.rewind();
+
+ ByteBuffer signedData = getLengthPrefixedSlice(signer);
+ // The first length prefixed slice is the sequence of digests which are not required
+ // when obtaining the signing certificate(s).
+ getLengthPrefixedSlice(signedData);
+ ByteBuffer certificatesBuffer = getLengthPrefixedSlice(signedData);
+ List<X509Certificate> certificates = new ArrayList<>();
+ while (certificatesBuffer.hasRemaining()) {
+ int certLength = certificatesBuffer.getInt();
+ byte[] certBytes = new byte[certLength];
+ if (certLength > certificatesBuffer.remaining()) {
+ throw new IllegalArgumentException(
+ "Cert index " + (certificates.size() + 1) + " under signer index "
+ + (signers.size() + 1) + " size out of range: " + certLength);
+ }
+ certificatesBuffer.get(certBytes);
+ GuaranteedEncodedFormX509Certificate signerCert =
+ new GuaranteedEncodedFormX509Certificate(
+ X509CertificateUtils.generateCertificate(certBytes), certBytes);
+ certificates.add(signerCert);
+ }
+ signers.add(Pair.of(certificates, signerBytes));
+ }
+ return signers;
+ }
+
+ /**
* Computes the digests of the given APK components according to the algorithms specified in the
* given SignerConfigs.
*
diff --git a/src/main/java/com/android/apksig/internal/apk/v2/V2SchemeSigner.java b/src/main/java/com/android/apksig/internal/apk/v2/V2SchemeSigner.java
index 156a163..b69b7d3 100644
--- a/src/main/java/com/android/apksig/internal/apk/v2/V2SchemeSigner.java
+++ b/src/main/java/com/android/apksig/internal/apk/v2/V2SchemeSigner.java
@@ -142,13 +142,27 @@
}
public static ApkSigningBlockUtils.SigningSchemeBlockAndDigests
+ generateApkSignatureSchemeV2Block(RunnablesExecutor executor,
+ DataSource beforeCentralDir,
+ DataSource centralDir,
+ DataSource eocd,
+ List<SignerConfig> signerConfigs,
+ boolean v3SigningEnabled)
+ throws IOException, InvalidKeyException, NoSuchAlgorithmException,
+ SignatureException {
+ return generateApkSignatureSchemeV2Block(executor, beforeCentralDir, centralDir, eocd,
+ signerConfigs, v3SigningEnabled, null);
+ }
+
+ public static ApkSigningBlockUtils.SigningSchemeBlockAndDigests
generateApkSignatureSchemeV2Block(
RunnablesExecutor executor,
DataSource beforeCentralDir,
DataSource centralDir,
DataSource eocd,
List<SignerConfig> signerConfigs,
- boolean v3SigningEnabled)
+ boolean v3SigningEnabled,
+ List<byte[]> preservedV2SignerBlocks)
throws IOException, InvalidKeyException, NoSuchAlgorithmException,
SignatureException {
Pair<List<SignerConfig>, Map<ContentDigestAlgorithm, byte[]>> digestInfo =
@@ -156,19 +170,24 @@
executor, beforeCentralDir, centralDir, eocd, signerConfigs);
return new ApkSigningBlockUtils.SigningSchemeBlockAndDigests(
generateApkSignatureSchemeV2Block(
- digestInfo.getFirst(), digestInfo.getSecond(), v3SigningEnabled),
+ digestInfo.getFirst(), digestInfo.getSecond(), v3SigningEnabled,
+ preservedV2SignerBlocks),
digestInfo.getSecond());
}
private static Pair<byte[], Integer> generateApkSignatureSchemeV2Block(
List<SignerConfig> signerConfigs,
Map<ContentDigestAlgorithm, byte[]> contentDigests,
- boolean v3SigningEnabled)
+ boolean v3SigningEnabled,
+ List<byte[]> preservedV2SignerBlocks)
throws NoSuchAlgorithmException, InvalidKeyException, SignatureException {
// FORMAT:
// * length-prefixed sequence of length-prefixed signer blocks.
List<byte[]> signerBlocks = new ArrayList<>(signerConfigs.size());
+ if (preservedV2SignerBlocks != null && preservedV2SignerBlocks.size() > 0) {
+ signerBlocks.addAll(preservedV2SignerBlocks);
+ }
int signerNumber = 0;
for (SignerConfig signerConfig : signerConfigs) {
signerNumber++;
diff --git a/src/test/java/com/android/apksig/ApkSignerTest.java b/src/test/java/com/android/apksig/ApkSignerTest.java
index 830d571..d799201 100644
--- a/src/test/java/com/android/apksig/ApkSignerTest.java
+++ b/src/test/java/com/android/apksig/ApkSignerTest.java
@@ -37,6 +37,7 @@
import com.android.apksig.internal.apk.v3.V3SchemeConstants;
import com.android.apksig.internal.asn1.Asn1BerParser;
import com.android.apksig.internal.util.AndroidSdkVersion;
+import com.android.apksig.internal.util.Pair;
import com.android.apksig.internal.util.Resources;
import com.android.apksig.internal.x509.RSAPublicKey;
import com.android.apksig.internal.x509.SubjectPublicKeyInfo;
@@ -70,8 +71,12 @@
import java.security.SignatureException;
import java.security.cert.X509Certificate;
import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.Collection;
import java.util.Collections;
import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
@RunWith(JUnit4.class)
public class ApkSignerTest {
@@ -88,6 +93,8 @@
private static final String SECOND_RSA_2048_SIGNER_RESOURCE_NAME = "rsa-2048_2";
private static final String THIRD_RSA_2048_SIGNER_RESOURCE_NAME = "rsa-2048_3";
+ private static final String EC_P256_SIGNER_RESOURCE_NAME = "ec-p256";
+
// This is the same cert as above with the modulus reencoded to remove the leading 0 sign bit.
private static final String FIRST_RSA_2048_SIGNER_CERT_WITH_NEGATIVE_MODULUS =
"rsa-2048_negmod.x509.der";
@@ -95,6 +102,11 @@
private static final String LINEAGE_RSA_2048_2_SIGNERS_RESOURCE_NAME =
"rsa-2048-lineage-2-signers";
+ // These are the ID and value of an extra signature block within the APK signing block that
+ // can be preserved through the setOtherSignersSignaturesPreserved API.
+ private final int EXTRA_BLOCK_ID = 0x7e57c0de;
+ private final byte[] EXTRA_BLOCK_VALUE = {0, 1, 2, 3, 4, 5, 6, 7};
+
@Rule
public TemporaryFolder mTemporaryFolder = new TemporaryFolder();
@@ -764,7 +776,8 @@
@Test
public void testEcSignedVerifies() throws Exception {
List<ApkSigner.SignerConfig> signers =
- Collections.singletonList(getDefaultSignerConfigFromResources("ec-p256"));
+ Collections.singletonList(
+ getDefaultSignerConfigFromResources(EC_P256_SIGNER_RESOURCE_NAME));
String in = "original.apk";
// NOTE: EC APK signatures are not supported prior to API Level 18
@@ -1322,6 +1335,258 @@
resourceZipFileContains("golden-pinsapp-signed.apk", "pinlist.meta"));
}
+ @Test
+ public void testOtherSignersSignaturesPreserved_extraSigBlock_signatureAppended()
+ throws Exception {
+ // The DefaultApkSignerEngine contains support to append a signature to an existing
+ // signing block; any existing signature blocks within the APK signing block should be
+ // left intact except for the original verity padding block (since this is regenerated) and
+ // the source stamp. This test verifies that an extra signature block is still in
+ // the APK signing block after appending a V2 signature.
+ List<ApkSigner.SignerConfig> ecP256SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(EC_P256_SIGNER_RESOURCE_NAME));
+
+ File signedApk = sign("v2-rsa-2048-with-extra-sig-block.apk",
+ new ApkSigner.Builder(ecP256SignerConfig)
+ .setV1SigningEnabled(false)
+ .setV2SigningEnabled(true)
+ .setV3SigningEnabled(false)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true));
+
+ ApkVerifier.Result result = verify(signedApk, null);
+ assertVerified(result);
+ assertResultContainsSigners(result, FIRST_RSA_2048_SIGNER_RESOURCE_NAME,
+ EC_P256_SIGNER_RESOURCE_NAME);
+ assertSigningBlockContains(signedApk, Pair.of(EXTRA_BLOCK_VALUE, EXTRA_BLOCK_ID));
+ }
+
+ @Test
+ public void testOtherSignersSignaturesPreserved_v1Only_signatureAppended() throws Exception {
+ // This test verifies appending an additional V1 signature to an existing V1 signer behaves
+ // similar to jarsigner where the APK is then verified as signed by both signers.
+ List<ApkSigner.SignerConfig> ecP256SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(EC_P256_SIGNER_RESOURCE_NAME));
+
+ File signedApk = sign("v1-only-with-rsa-2048.apk",
+ new ApkSigner.Builder(ecP256SignerConfig)
+ .setV1SigningEnabled(true)
+ .setV2SigningEnabled(false)
+ .setV3SigningEnabled(false)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true));
+
+ ApkVerifier.Result result = verify(signedApk, null);
+ assertVerified(result);
+ assertResultContainsSigners(result, FIRST_RSA_2048_SIGNER_RESOURCE_NAME,
+ EC_P256_SIGNER_RESOURCE_NAME);
+ }
+
+ @Test
+ public void testOtherSignersSignaturesPreserved_v3OnlyDifferentSigner_throwsException()
+ throws Exception {
+ // The V3 Signature Scheme only supports a single signer; if an attempt is made to append
+ // a different signer to a V3 signature then an exception should be thrown.
+ // The APK used for this test is signed with the ec-p256 signer so use the rsa-2048 to
+ // attempt to append a different signature.
+ List<ApkSigner.SignerConfig> rsa2048SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(FIRST_RSA_2048_SIGNER_RESOURCE_NAME));
+
+ assertThrows(IllegalStateException.class, () ->
+ sign("v3-only-with-stamp.apk",
+ new ApkSigner.Builder(rsa2048SignerConfig)
+ .setV1SigningEnabled(false)
+ .setV2SigningEnabled(false)
+ .setV3SigningEnabled(true)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true))
+ );
+ }
+
+ @Test
+ public void testOtherSignersSignaturesPreserved_v2OnlyAppendV2V3SameSigner_signatureAppended()
+ throws Exception {
+ // A V2 and V3 signature can be appended to an existing V2 signature if the same signer is
+ // used to resign the APK; this could be used in a case where an APK was previously signed
+ // with just the V2 signature scheme along with additional non-APK signing scheme signature
+ // blocks and the signer wanted to preserve those existing blocks.
+ List<ApkSigner.SignerConfig> rsa2048SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(FIRST_RSA_2048_SIGNER_RESOURCE_NAME));
+
+ File signedApk = sign("v2-rsa-2048-with-extra-sig-block.apk",
+ new ApkSigner.Builder(rsa2048SignerConfig)
+ .setV1SigningEnabled(false)
+ .setV2SigningEnabled(true)
+ .setV3SigningEnabled(true)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true));
+
+ ApkVerifier.Result result = verify(signedApk, null);
+ assertVerified(result);
+ assertResultContainsSigners(result, FIRST_RSA_2048_SIGNER_RESOURCE_NAME);
+ assertSigningBlockContains(signedApk, Pair.of(EXTRA_BLOCK_VALUE, EXTRA_BLOCK_ID));
+ }
+
+ @Test
+ public void testOtherSignersSignaturesPreserved_v2OnlyAppendV3SameSigner_throwsException()
+ throws Exception {
+ // A V3 only signature cannot be appended to an existing V2 signature, even when using the
+ // same signer, since the V2 signature would then not contain the stripping protection for
+ // the V3 signature. If the same signer is being used then the signer should be configured
+ // to resign using the V2 signature scheme as well as the V3 signature scheme.
+ List<ApkSigner.SignerConfig> rsa2048SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(FIRST_RSA_2048_SIGNER_RESOURCE_NAME));
+
+ assertThrows(IllegalStateException.class, () ->
+ sign("v2-rsa-2048-with-extra-sig-block.apk",
+ new ApkSigner.Builder(rsa2048SignerConfig)
+ .setV1SigningEnabled(false)
+ .setV2SigningEnabled(false)
+ .setV3SigningEnabled(true)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true)));
+ }
+
+ @Test
+ public void testOtherSignersSignaturesPreserved_v1v2IndividuallySign_signaturesAppended()
+ throws Exception {
+ // One of the primary requirements for appending signatures is when an APK has already
+ // released with two signers; with the minimum signature scheme v2 requirement for target
+ // SDK version 30+ each signer must be able to append their signature to the existing
+ // signature block. This test verifies an APK with appended signatures verifies as expected
+ // after a series of appending V1 and V2 signatures.
+ List<ApkSigner.SignerConfig> rsa2048SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(FIRST_RSA_2048_SIGNER_RESOURCE_NAME));
+ List<ApkSigner.SignerConfig> ecP256SignerConfig = Collections.singletonList(
+ getDefaultSignerConfigFromResources(EC_P256_SIGNER_RESOURCE_NAME));
+
+ // When two parties are signing an APK the first must sign with both V1 and V2; this will
+ // write the stripping-protection attribute to the V1 signature.
+ File signedApk = sign("original.apk",
+ new ApkSigner.Builder(rsa2048SignerConfig)
+ .setV1SigningEnabled(true)
+ .setV2SigningEnabled(true)
+ .setV3SigningEnabled(false)
+ .setV4SigningEnabled(false));
+
+ // The second party can then append their signature with both the V1 and V2 signature; this
+ // will invalidate the V2 signature of the initial signer since the APK itself will be
+ // modified with this signers V1 / jar signature.
+ signedApk = sign(signedApk,
+ new ApkSigner.Builder(ecP256SignerConfig)
+ .setV1SigningEnabled(true)
+ .setV2SigningEnabled(true)
+ .setV3SigningEnabled(false)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true));
+
+ // The first party will then need to resign with just the V2 signature after its previous
+ // signature was invalidated by the V1 signature of the second signer; however since this
+ // signature is appended its previous V2 signature should be removed from the signature
+ // block and replaced with this new signature while preserving the V2 signature of the
+ // other signer.
+ signedApk = sign(signedApk,
+ new ApkSigner.Builder(rsa2048SignerConfig)
+ .setV1SigningEnabled(false)
+ .setV2SigningEnabled(true)
+ .setV3SigningEnabled(false)
+ .setV4SigningEnabled(false)
+ .setOtherSignersSignaturesPreserved(true));
+
+ ApkVerifier.Result result = verify(signedApk, null);
+ assertVerified(result);
+ assertResultContainsSigners(result, FIRST_RSA_2048_SIGNER_RESOURCE_NAME,
+ EC_P256_SIGNER_RESOURCE_NAME);
+ }
+
+ /**
+ * Asserts the provided {@code signedApk} contains a signature block with the expected
+ * {@code byte[]} value and block ID as specified in the {@code expectedBlock}.
+ */
+ private static void assertSigningBlockContains(File signedApk,
+ Pair<byte[], Integer> expectedBlock) throws Exception {
+ try (RandomAccessFile apkFile = new RandomAccessFile(signedApk, "r")) {
+ ApkUtils.ApkSigningBlock apkSigningBlock = ApkUtils.findApkSigningBlock(
+ DataSources.asDataSource(apkFile));
+ List<Pair<byte[], Integer>> signatureBlocks =
+ ApkSigningBlockUtils.getApkSignatureBlocks(apkSigningBlock.getContents());
+ for (Pair<byte[], Integer> signatureBlock : signatureBlocks) {
+ if (signatureBlock.getSecond().equals(expectedBlock.getSecond())) {
+ if (Arrays.equals(signatureBlock.getFirst(), expectedBlock.getFirst())) {
+ return;
+ }
+ }
+ }
+ fail(String.format(
+ "The APK signing block did not contain the expected block with ID %08x",
+ expectedBlock.getSecond()));
+ }
+ }
+
+ /**
+ * Asserts the provided verification {@code result} contains the expected {@code signers} for
+ * each scheme that was used to verify the APK's signature.
+ */
+ private static void assertResultContainsSigners(ApkVerifier.Result result, String... signers)
+ throws Exception {
+ // A result must be successfully verified before verifying any of the result's signers.
+ assertTrue(result.isVerified());
+
+ List<X509Certificate> expectedSigners = new ArrayList<>();
+ for (String signer : signers) {
+ ApkSigner.SignerConfig signerConfig = getDefaultSignerConfigFromResources(signer);
+ expectedSigners.addAll(signerConfig.getCertificates());
+ }
+
+ if (result.isVerifiedUsingV1Scheme()) {
+ Set<X509Certificate> v1Signers = new HashSet<>();
+ for (ApkVerifier.Result.V1SchemeSignerInfo signer : result.getV1SchemeSigners()) {
+ v1Signers.add(signer.getCertificate());
+ }
+ assertEquals(expectedSigners.size(), v1Signers.size());
+ assertTrue("Expected V1 signers: " + getAllSubjectNamesFrom(expectedSigners)
+ + ", actual V1 signers: " + getAllSubjectNamesFrom(v1Signers),
+ v1Signers.containsAll(expectedSigners));
+ }
+
+ if (result.isVerifiedUsingV2Scheme()) {
+ Set<X509Certificate> v2Signers = new HashSet<>();
+ for (ApkVerifier.Result.V2SchemeSignerInfo signer : result.getV2SchemeSigners()) {
+ v2Signers.add(signer.getCertificate());
+ }
+ assertEquals(expectedSigners.size(), v2Signers.size());
+ assertTrue("Expected V2 signers: " + getAllSubjectNamesFrom(expectedSigners)
+ + ", actual V2 signers: " + getAllSubjectNamesFrom(v2Signers),
+ v2Signers.containsAll(expectedSigners));
+ }
+
+ if (result.isVerifiedUsingV3Scheme()) {
+ Set<X509Certificate> v3Signers = new HashSet<>();
+ for (ApkVerifier.Result.V3SchemeSignerInfo signer : result.getV3SchemeSigners()) {
+ v3Signers.add(signer.getCertificate());
+ }
+ assertEquals(expectedSigners.size(), v3Signers.size());
+ assertTrue("Expected V3 signers: " + getAllSubjectNamesFrom(expectedSigners)
+ + ", actual V3 signers: " + getAllSubjectNamesFrom(v3Signers),
+ v3Signers.containsAll(expectedSigners));
+ }
+ }
+
+ /**
+ * Returns a comma delimited {@code String} containing all of the Subject Names from the
+ * provided {@code certificates}.
+ */
+ private static String getAllSubjectNamesFrom(Collection<X509Certificate> certificates) {
+ StringBuilder result = new StringBuilder();
+ for (X509Certificate certificate : certificates) {
+ if (result.length() > 0) {
+ result.append(", ");
+ }
+ result.append(certificate.getSubjectDN().getName());
+ }
+ return result.toString();
+ }
+
private static boolean resourceZipFileContains(String resourceName, String zipEntryName)
throws IOException {
ZipInputStream zip = new ZipInputStream(
@@ -1449,11 +1714,21 @@
}
}
- private File sign(String inResourceName, ApkSigner.Builder apkSignerBuilder)
- throws Exception {
+ private File sign(File inApkFile, ApkSigner.Builder apkSignerBuilder) throws Exception {
+ try (RandomAccessFile apkFile = new RandomAccessFile(inApkFile, "r")) {
+ DataSource in = DataSources.asDataSource(apkFile);
+ return sign(in, apkSignerBuilder);
+ }
+ }
+
+ private File sign(String inResourceName, ApkSigner.Builder apkSignerBuilder) throws Exception {
DataSource in =
DataSources.asDataSource(
ByteBuffer.wrap(Resources.toByteArray(getClass(), inResourceName)));
+ return sign(in, apkSignerBuilder);
+ }
+
+ private File sign(DataSource in, ApkSigner.Builder apkSignerBuilder) throws Exception {
File outFile = mTemporaryFolder.newFile();
apkSignerBuilder.setInputApk(in).setOutputApk(outFile);
diff --git a/src/test/resources/com/android/apksig/v1-only-with-rsa-2048.apk b/src/test/resources/com/android/apksig/v1-only-with-rsa-2048.apk
new file mode 100644
index 0000000..61f4122
--- /dev/null
+++ b/src/test/resources/com/android/apksig/v1-only-with-rsa-2048.apk
Binary files differ
diff --git a/src/test/resources/com/android/apksig/v2-rsa-2048-with-extra-sig-block.apk b/src/test/resources/com/android/apksig/v2-rsa-2048-with-extra-sig-block.apk
new file mode 100644
index 0000000..94b54c9
--- /dev/null
+++ b/src/test/resources/com/android/apksig/v2-rsa-2048-with-extra-sig-block.apk
Binary files differ
