Merge "Solve AppBackupUtils.signaturesMatch() policies" into oc-mr1-dev (a743c01d) · Commits · e / os / android_frameworks_base

services/backup/java/com/android/server/backup/BackupManagerService.java

+24 −13

Original line number	Diff line number	Diff line
		@@ -119,6 +119,7 @@ import android.util.StringBuilderPrinter;
		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.backup.IBackupTransport;
		import com.android.internal.backup.IObbBackupService;
		import com.android.internal.util.ArrayUtils;
		import com.android.internal.util.DumpUtils;
		import com.android.server.AppWidgetBackupBridge;
		import com.android.server.EventLogTags;
		@@ -8416,7 +8417,19 @@ if (MORE_DEBUG) Slog.v(TAG, " + got " + nRead + "; now wanting " + (size - soF

		// ----- Restore handling -----

		// Old style: directly match the stored vs on device signature blocks
		/**
		* Returns whether the signatures stored {@param storedSigs}, coming from the source apk, match
		* the signatures of the apk installed on the device, the target apk. If the target resides in
		* the system partition we return true. Otherwise it's considered a match if both conditions
		* hold:
		*
		* <ul>
		* <li>Source and target have at least one signature each
		* <li>Target contains all signatures in source
		* </ul>
		*
		* Note that if {@param target} is null we return false.
		*/
		static boolean signaturesMatch(Signature[] storedSigs, PackageInfo target) {
		if (target == null) {
		return false;
		@@ -8428,26 +8441,24 @@ if (MORE_DEBUG) Slog.v(TAG, " + got " + nRead + "; now wanting " + (size - soF
		// partition will be signed with the device's platform certificate, so on
		// different phones the same system app will have different signatures.)
		if ((target.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
		if (MORE_DEBUG) Slog.v(TAG, "System app " + target.packageName + " - skipping sig check");
		if (MORE_DEBUG) {
		Slog.v(TAG, "System app " + target.packageName + " - skipping sig check");
		}
		return true;
		}

		// Allow unsigned apps, but not signed on one device and unsigned on the other
		// !!! TODO: is this the right policy?
		Signature[] deviceSigs = target.signatures;
		if (MORE_DEBUG) Slog.v(TAG, "signaturesMatch(): stored=" + storedSigs
		+ " device=" + deviceSigs);
		if ((storedSigs == null \|\| storedSigs.length == 0)
		&& (deviceSigs == null \|\| deviceSigs.length == 0)) {
		return true;
		if (MORE_DEBUG) {
		Slog.v(TAG, "signaturesMatch(): stored=" + storedSigs + " device=" + deviceSigs);
		}
		if (storedSigs == null \|\| deviceSigs == null) {

		// Don't allow unsigned apps on either end
		if (ArrayUtils.isEmpty(storedSigs) \|\| ArrayUtils.isEmpty(deviceSigs)) {
		return false;
		}

		// !!! TODO: this demands that every stored signature match one
		// that is present on device, and does not demand the converse.
		// Is this this right policy?
		// Signatures can be added over time, so the target-device apk needs to contain all the
		// source-device apk signatures, but not necessarily the other way around.
		int nStored = storedSigs.length;
		int nDevice = deviceSigs.length;

services/backup/java/com/android/server/backup/utils/AppBackupUtils.java

+18 −13

Original line number	Diff line number	Diff line
		@@ -26,6 +26,8 @@ import android.content.pm.Signature;
		import android.os.Process;
		import android.util.Slog;

		import com.android.internal.util.ArrayUtils;

		/**
		* Utility methods wrapping operations on ApplicationInfo and PackageInfo.
		*/
		@@ -91,9 +93,18 @@ public class AppBackupUtils {
		}

		/**
		* Old style: directly match the stored vs on device signature blocks.
		* Returns whether the signatures stored {@param storedSigs}, coming from the source apk, match
		* the signatures of the apk installed on the device, the target apk. If the target resides in
		* the system partition we return true. Otherwise it's considered a match if both conditions
		* hold:
		*
		* <ul>
		* <li>Source and target have at least one signature each
		* <li>Target contains all signatures in source
		* </ul>
		*
		* Note that if {@param target} is null we return false.
		*/
		// TODO(b/37977154): Resolve questionable policies.
		public static boolean signaturesMatch(Signature[] storedSigs, PackageInfo target) {
		if (target == null) {
		return false;
		@@ -111,24 +122,18 @@ public class AppBackupUtils {
		return true;
		}

		// Allow unsigned apps, but not signed on one device and unsigned on the other
		// TODO(b/37977154): is this the right policy?
		Signature[] deviceSigs = target.signatures;
		if (MORE_DEBUG) {
		Slog.v(TAG, "signaturesMatch(): stored=" + storedSigs + " device=" + deviceSigs);
		}
		if ((storedSigs == null \|\| storedSigs.length == 0)
		&& (deviceSigs == null \|\| deviceSigs.length == 0)) {
		return true;
		}
		// TODO(b/37977154): This allows empty stored signature, is this right?
		if (storedSigs == null \|\| deviceSigs == null) {

		// Don't allow unsigned apps on either end
		if (ArrayUtils.isEmpty(storedSigs) \|\| ArrayUtils.isEmpty(deviceSigs)) {
		return false;
		}

		// TODO(b/37977154): this demands that every stored signature match one
		// that is present on device, and does not demand the converse.
		// Is this this right policy?
		// Signatures can be added over time, so the target-device apk needs to contain all the
		// source-device apk signatures, but not necessarily the other way around.
		int nStored = storedSigs.length;
		int nDevice = deviceSigs.length;

services/tests/servicestests/src/com/android/server/backup/utils/AppBackupUtilsTest.java

+42 −119

Original line number	Diff line number	Diff line
		@@ -31,8 +31,6 @@ import com.android.server.backup.RefactoredBackupManagerService;
		import org.junit.Test;
		import org.junit.runner.RunWith;

		import java.util.Random;

		@SmallTest
		@Presubmit
		@RunWith(AndroidJUnit4.class)
		@@ -40,7 +38,10 @@ public class AppBackupUtilsTest {
		private static final String CUSTOM_BACKUP_AGENT_NAME = "custom.backup.agent";
		private static final String TEST_PACKAGE_NAME = "test_package";

		private final Random mRandom = new Random(1000000009);
		private static final Signature SIGNATURE_1 = generateSignature((byte) 1);
		private static final Signature SIGNATURE_2 = generateSignature((byte) 2);
		private static final Signature SIGNATURE_3 = generateSignature((byte) 3);
		private static final Signature SIGNATURE_4 = generateSignature((byte) 4);

		@Test
		public void appIsEligibleForBackup_backupNotAllowed_returnsFalse() throws Exception {
		@@ -220,7 +221,7 @@ public class AppBackupUtilsTest {

		@Test
		public void signaturesMatch_targetIsNull_returnsFalse() throws Exception {
		boolean result = AppBackupUtils.signaturesMatch(new Signature[0], null);
		boolean result = AppBackupUtils.signaturesMatch(new Signature[] {SIGNATURE_1}, null);

		assertThat(result).isFalse();
		}
		@@ -237,61 +238,63 @@ public class AppBackupUtilsTest {
		}

		@Test
		public void signaturesMatch_allowsUnsignedApps_bothSignaturesNull_returnsTrue()
		public void signaturesMatch_disallowsUnsignedApps_storedSignatureNull_returnsFalse()
		throws Exception {
		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = null;
		packageInfo.signatures = new Signature[] {SIGNATURE_1};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(null, packageInfo);

		assertThat(result).isTrue();
		assertThat(result).isFalse();
		}

		@Test
		public void signaturesMatch_allowsUnsignedApps_bothSignaturesEmpty_returnsTrue()
		public void signaturesMatch_disallowsUnsignedApps_storedSignatureEmpty_returnsFalse()
		throws Exception {
		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[0];
		packageInfo.signatures = new Signature[] {SIGNATURE_1};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(new Signature[0], packageInfo);

		assertThat(result).isTrue();
		assertThat(result).isFalse();
		}


		@Test
		public void
		signaturesMatch_allowsUnsignedApps_storedSignatureNullTargetSignatureEmpty_returnsTrue()
		signaturesMatch_disallowsUnsignedApps_targetSignatureEmpty_returnsFalse()
		throws Exception {
		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[0];
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(null, packageInfo);
		boolean result = AppBackupUtils.signaturesMatch(new Signature[] {SIGNATURE_1},
		packageInfo);

		assertThat(result).isTrue();
		assertThat(result).isFalse();
		}

		@Test
		public void
		signaturesMatch_allowsUnsignedApps_storedSignatureEmptyTargetSignatureNull_returnsTrue()
		signaturesMatch_disallowsUnsignedApps_targetSignatureNull_returnsFalse()
		throws Exception {
		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = null;
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(new Signature[0], packageInfo);
		boolean result = AppBackupUtils.signaturesMatch(new Signature[] {SIGNATURE_1},
		packageInfo);

		assertThat(result).isTrue();
		assertThat(result).isFalse();
		}

		@Test
		public void
		signaturesMatch_disallowsAppsUnsignedOnOnlyOneDevice_storedSignatureIsNull_returnsFalse()
		public void signaturesMatch_disallowsUnsignedApps_bothSignaturesNull_returnsFalse()
		throws Exception {
		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[]{generateRandomSignature()};
		packageInfo.signatures = null;
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(null, packageInfo);
		@@ -300,37 +303,25 @@ public class AppBackupUtilsTest {
		}

		@Test
		public void
		signaturesMatch_disallowsAppsUnsignedOnOnlyOneDevice_targetSignatureIsNull_returnsFalse()
		public void signaturesMatch_disallowsUnsignedApps_bothSignaturesEmpty_returnsFalse()
		throws Exception {
		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = null;
		packageInfo.signatures = new Signature[0];
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(new Signature[]{generateRandomSignature()},
		packageInfo);
		boolean result = AppBackupUtils.signaturesMatch(new Signature[0], packageInfo);

		assertThat(result).isFalse();
		}

		@Test
		public void signaturesMatch_signaturesMatch_returnsTrue() throws Exception {
		Signature signature1 = generateRandomSignature();
		Signature signature2 = generateRandomSignature();
		Signature signature3 = generateRandomSignature();
		assertThat(signature1).isNotEqualTo(signature2);
		assertThat(signature2).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature3);

		Signature signature1Copy = new Signature(signature1.toByteArray());
		Signature signature2Copy = new Signature(signature2.toByteArray());
		Signature signature3Copy = new Signature(signature3.toByteArray());
		assertThat(signature1Copy).isEqualTo(signature1);
		assertThat(signature2Copy).isEqualTo(signature2);
		assertThat(signature3Copy).isEqualTo(signature3);
		public void signaturesMatch_equalSignatures_returnsTrue() throws Exception {
		Signature signature1Copy = new Signature(SIGNATURE_1.toByteArray());
		Signature signature2Copy = new Signature(SIGNATURE_2.toByteArray());
		Signature signature3Copy = new Signature(SIGNATURE_3.toByteArray());

		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[]{signature1, signature2, signature3};
		packageInfo.signatures = new Signature[]{SIGNATURE_1, SIGNATURE_2, SIGNATURE_3};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(
		@@ -341,20 +332,11 @@ public class AppBackupUtilsTest {

		@Test
		public void signaturesMatch_extraSignatureInTarget_returnsTrue() throws Exception {
		Signature signature1 = generateRandomSignature();
		Signature signature2 = generateRandomSignature();
		Signature signature3 = generateRandomSignature();
		assertThat(signature1).isNotEqualTo(signature2);
		assertThat(signature2).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature3);

		Signature signature1Copy = new Signature(signature1.toByteArray());
		Signature signature2Copy = new Signature(signature2.toByteArray());
		assertThat(signature1Copy).isEqualTo(signature1);
		assertThat(signature2Copy).isEqualTo(signature2);
		Signature signature1Copy = new Signature(SIGNATURE_1.toByteArray());
		Signature signature2Copy = new Signature(SIGNATURE_2.toByteArray());

		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[]{signature1, signature2, signature3};
		packageInfo.signatures = new Signature[]{SIGNATURE_1, SIGNATURE_2, SIGNATURE_3};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(
		@@ -365,96 +347,37 @@ public class AppBackupUtilsTest {

		@Test
		public void signaturesMatch_extraSignatureInStored_returnsFalse() throws Exception {
		Signature signature1 = generateRandomSignature();
		Signature signature2 = generateRandomSignature();
		Signature signature3 = generateRandomSignature();
		assertThat(signature1).isNotEqualTo(signature2);
		assertThat(signature2).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature3);

		Signature signature1Copy = new Signature(signature1.toByteArray());
		Signature signature2Copy = new Signature(signature2.toByteArray());
		assertThat(signature1Copy).isEqualTo(signature1);
		assertThat(signature2Copy).isEqualTo(signature2);
		Signature signature1Copy = new Signature(SIGNATURE_1.toByteArray());
		Signature signature2Copy = new Signature(SIGNATURE_2.toByteArray());

		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[]{signature1Copy, signature2Copy};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(
		new Signature[]{signature1, signature2, signature3}, packageInfo);

		assertThat(result).isFalse();
		}

		@Test
		public void signaturesMatch_emptyStoredSignatures_returnsTrue() throws Exception {
		Signature signature1 = generateRandomSignature();
		Signature signature2 = generateRandomSignature();
		Signature signature3 = generateRandomSignature();
		assertThat(signature1).isNotEqualTo(signature2);
		assertThat(signature2).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature3);

		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[]{signature1, signature2, signature3};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(new Signature[0], packageInfo);

		assertThat(result).isTrue();
		}

		@Test
		public void signaturesMatch_emptyTargetSignatures_returnsFalse() throws Exception {
		Signature signature1 = generateRandomSignature();
		Signature signature2 = generateRandomSignature();
		Signature signature3 = generateRandomSignature();
		assertThat(signature1).isNotEqualTo(signature2);
		assertThat(signature2).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature3);

		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[0];
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(
		new Signature[]{signature1, signature2, signature3}, packageInfo);
		new Signature[]{SIGNATURE_1, SIGNATURE_2, SIGNATURE_3}, packageInfo);

		assertThat(result).isFalse();
		}

		@Test
		public void signaturesMatch_oneNonMatchingSignature_returnsFalse() throws Exception {
		Signature signature1 = generateRandomSignature();
		Signature signature2 = generateRandomSignature();
		Signature signature3 = generateRandomSignature();
		Signature signature4 = generateRandomSignature();
		assertThat(signature1).isNotEqualTo(signature2);
		assertThat(signature2).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature3);
		assertThat(signature1).isNotEqualTo(signature4);
		assertThat(signature2).isNotEqualTo(signature4);
		assertThat(signature3).isNotEqualTo(signature4);

		Signature signature1Copy = new Signature(signature1.toByteArray());
		Signature signature2Copy = new Signature(signature2.toByteArray());
		assertThat(signature1Copy).isEqualTo(signature1);
		assertThat(signature2Copy).isEqualTo(signature2);
		Signature signature1Copy = new Signature(SIGNATURE_1.toByteArray());
		Signature signature2Copy = new Signature(SIGNATURE_2.toByteArray());

		PackageInfo packageInfo = new PackageInfo();
		packageInfo.signatures = new Signature[]{signature1, signature2, signature3};
		packageInfo.signatures = new Signature[]{SIGNATURE_1, SIGNATURE_2, SIGNATURE_3};
		packageInfo.applicationInfo = new ApplicationInfo();

		boolean result = AppBackupUtils.signaturesMatch(
		new Signature[]{signature1Copy, signature2Copy, signature4}, packageInfo);
		new Signature[]{signature1Copy, signature2Copy, SIGNATURE_4}, packageInfo);

		assertThat(result).isFalse();
		}

		private Signature generateRandomSignature() {
		private static Signature generateSignature(byte i) {
		byte[] signatureBytes = new byte[256];
		mRandom.nextBytes(signatureBytes);
		signatureBytes[0] = i;
		return new Signature(signatureBytes);
		}
		}