Examples with ApkSigningBlock com.android.apksig.apk.ApkUtils.ApkSigningBlock used on opensource projects

Example 1 with ApkSigningBlock

use of com.android.apksig.apk.ApkUtils.ApkSigningBlock in project LSPatch by LSPosed.

the class SigningBlockUtils method extractBlock.

/**
 * Extract a block with the given id from the APK. If there is more than one block with the same
 * ID, the first block will be returned. If there are no block with the give id, {@code null} will
 * be returned.
 *
 * @param apk APK file
 * @param blockId id of the block to be extracted.
 */
@Nullable
public static ByteBuffer extractBlock(File apk, int blockId) throws IOException, ZipFormatException, ApkSigningBlockNotFoundException {
    try (RandomAccessFile file = new RandomAccessFile(apk, "r")) {
        DataSource apkDataSource = DataSources.asDataSource(file);
        ApkSigningBlock signingBlockInfo = ApkUtils.findApkSigningBlock(apkDataSource, ApkUtils.findZipSections(apkDataSource));
        DataSource wholeV2Block = signingBlockInfo.getContents();
        final int lengthAndIdByteCount = BLOCK_LENGTH_NUM_BYTES + BLOCK_ID_NUM_BYTES;
        DataSource signingBlock = wholeV2Block.slice(SIZE_OF_BLOCK_NUM_BYTES, wholeV2Block.size() - SIZE_OF_BLOCK_NUM_BYTES - MAGIC_NUM_BYTES);
        ByteBuffer lengthAndId = ByteBuffer.allocate(lengthAndIdByteCount).order(ByteOrder.LITTLE_ENDIAN);
        for (int index = 0; index <= signingBlock.size() - lengthAndIdByteCount; ) {
            signingBlock.copyTo(index, lengthAndIdByteCount, lengthAndId);
            lengthAndId.flip();
            int blockLength = (int) lengthAndId.getLong();
            int id = lengthAndId.getInt();
            lengthAndId.flip();
            if (id == blockId) {
                ByteBuffer block = ByteBuffer.allocate(blockLength - BLOCK_ID_NUM_BYTES);
                signingBlock.copyTo(index + lengthAndIdByteCount, blockLength - BLOCK_ID_NUM_BYTES, block);
                block.flip();
                return block;
            }
            index += blockLength + BLOCK_LENGTH_NUM_BYTES;
        }
        return null;
    }
}