APK signature verification: use FileChannel#size

RandomAccessFile#length returns 0 for block devices while
FileChannel#size returns the correct size.

APK signature verification utils should work with block-device zip files
when Android is running as a guest OS and APK/APEX files are passed via
block devices.

This is a follow-up of 1257f1505cb2ac75b6959e16d195c7c4bac8ee06.

Bug: 193592496
Bug: 192366904
Test: FrameworksServicesTests
Merged-In: I3015fc30574c36c18c0d0c9ae7453d33a1349927
Change-Id: I3015fc30574c36c18c0d0c9ae7453d33a1349927
(cherry picked from commit 310edbe3c7202581bf10b6a621a287b297d73261)

4 files changed, 7 insertions, 7 deletions

diff --git a/core/java/android/util/apk/ApkSignatureSchemeV2Verifier.java b/core/java/android/util/apk/ApkSignatureSchemeV2Verifier.java
index 346fe293d7ae..077115769374 100644
--- a/core/java/android/util/apk/ApkSignatureSchemeV2Verifier.java
+++ b/core/java/android/util/apk/ApkSignatureSchemeV2Verifier.java
@@ -210,7 +210,7 @@ public class ApkSignatureSchemeV2Verifier {
         if (contentDigests.containsKey(CONTENT_DIGEST_VERITY_CHUNKED_SHA256)) {
             byte[] verityDigest = contentDigests.get(CONTENT_DIGEST_VERITY_CHUNKED_SHA256);
             verityRootHash = ApkSigningBlockUtils.parseVerityDigestAndVerifySourceLength(
-                    verityDigest, apk.length(), signatureInfo);
+                    verityDigest, apk.getChannel().size(), signatureInfo);
         }
 
         byte[] digest = pickBestDigestForV4(contentDigests);
diff --git a/core/java/android/util/apk/ApkSignatureSchemeV3Verifier.java b/core/java/android/util/apk/ApkSignatureSchemeV3Verifier.java
index 4ab541b616ed..44f01a4f9759 100644
--- a/core/java/android/util/apk/ApkSignatureSchemeV3Verifier.java
+++ b/core/java/android/util/apk/ApkSignatureSchemeV3Verifier.java
@@ -209,7 +209,7 @@ public class ApkSignatureSchemeV3Verifier {
         if (contentDigests.containsKey(CONTENT_DIGEST_VERITY_CHUNKED_SHA256)) {
             byte[] verityDigest = contentDigests.get(CONTENT_DIGEST_VERITY_CHUNKED_SHA256);
             result.verityRootHash = ApkSigningBlockUtils.parseVerityDigestAndVerifySourceLength(
-                    verityDigest, apk.length(), signatureInfo);
+                    verityDigest, apk.getChannel().size(), signatureInfo);
         }
 
         result.digest = pickBestDigestForV4(contentDigests);
diff --git a/core/java/android/util/apk/ApkSigningBlockUtils.java b/core/java/android/util/apk/ApkSigningBlockUtils.java
index 6efe95cb9e92..f79b5b99b7e6 100644
--- a/core/java/android/util/apk/ApkSigningBlockUtils.java
+++ b/core/java/android/util/apk/ApkSigningBlockUtils.java
@@ -349,7 +349,7 @@ final class ApkSigningBlockUtils {
             SignatureInfo signatureInfo) throws SecurityException {
         try {
             byte[] expectedRootHash = parseVerityDigestAndVerifySourceLength(expectedDigest,
-                    apk.length(), signatureInfo);
+                    apk.getChannel().size(), signatureInfo);
             VerityBuilder.VerityResult verity = VerityBuilder.generateApkVerityTree(apk,
                     signatureInfo, new ByteBufferFactory() {
                         @Override
diff --git a/core/java/android/util/apk/VerityBuilder.java b/core/java/android/util/apk/VerityBuilder.java
index e81e3f7b38d6..3dfa4cd1a0d2 100644
--- a/core/java/android/util/apk/VerityBuilder.java
+++ b/core/java/android/util/apk/VerityBuilder.java
@@ -90,7 +90,7 @@ public abstract class VerityBuilder {
             throws IOException, SecurityException, NoSuchAlgorithmException, DigestException {
         long signingBlockSize =
                 signatureInfo.centralDirOffset - signatureInfo.apkSigningBlockOffset;
-        long dataSize = apk.length() - signingBlockSize;
+        long dataSize = apk.getChannel().size() - signingBlockSize;
         int[] levelOffset = calculateVerityLevelOffset(dataSize);
         int merkleTreeSize = levelOffset[levelOffset.length - 1];
 
@@ -108,7 +108,7 @@ public abstract class VerityBuilder {
             @NonNull SignatureInfo signatureInfo, @NonNull ByteBuffer footerOutput)
             throws IOException {
         footerOutput.order(ByteOrder.LITTLE_ENDIAN);
-        generateApkVerityHeader(footerOutput, apk.length(), DEFAULT_SALT);
+        generateApkVerityHeader(footerOutput, apk.getChannel().size(), DEFAULT_SALT);
         long signingBlockSize =
                 signatureInfo.centralDirOffset - signatureInfo.apkSigningBlockOffset;
         generateApkVerityExtensions(footerOutput, signatureInfo.apkSigningBlockOffset,
@@ -310,11 +310,11 @@ public abstract class VerityBuilder {
                 eocdCdOffsetFieldPosition + ZIP_EOCD_CENTRAL_DIR_OFFSET_FIELD_SIZE;
         consumeByChunk(digester,
                 new MemoryMappedFileDataSource(apk.getFD(), offsetAfterEocdCdOffsetField,
-                    apk.length() - offsetAfterEocdCdOffsetField),
+                    apk.getChannel().size() - offsetAfterEocdCdOffsetField),
                 MMAP_REGION_SIZE_BYTES);
 
         // 5. Pad 0s up to the nearest 4096-byte block before hashing.
-        int lastIncompleteChunkSize = (int) (apk.length() % CHUNK_SIZE_BYTES);
+        int lastIncompleteChunkSize = (int) (apk.getChannel().size() % CHUNK_SIZE_BYTES);
         if (lastIncompleteChunkSize != 0) {
             digester.consume(ByteBuffer.allocate(CHUNK_SIZE_BYTES - lastIncompleteChunkSize));
         }