Question

嘿所有人。我正在从一个sql格式的文件读到另一个，并且中间的两个字节正在被破坏，我认为这是我没有做的一些准备或保护。

损坏数据的示例：

//From the file that is read from. added ** to emphasize the corrupted byte
insert into viruses (virusSig,virusHash) values (
X'579fdc569b170419e15750f0feb360aa9c58d8**90**eede50def97ee7cb03b9e905',
X'ee002fe5');

//From the file that is written to. added ** to emphasize the corrupted byte
insert into changes (filepath,loc,dat,vir,hash) values (
'E:\MyDocs\intel\antivirus\RandomFiles\0\2\5\11\24\49\EG1AxxeJSr.data',
243540,
X'9f4246ff8c73c5a5b470cab8c38416929c4eacc1e0021d5ac1fdbb88145d3e6f',
X'579fdc569b170419e15750f0feb360aa9c58d8**3f**eede50def97ee7cb03b9e905',
X'6546dd27');

读取/写入的代码：

public static void insertViruses(FileLocation[] locations, byte[][] viruses, String logpath)
{
    int numViruses = viruses.length;
    int virusLength = GenerateRandomCorpus.virusSignatureLengthInBytes;

    try{


        for (int i = 0; i < numViruses; i++)
        {   
            FileOutputStream logwriter = new FileOutputStream(logpath, true);

            // Prep to copy section
            int locationOfChange = locations[i].index;
            String filepathToChange = locations[i].filepath;
            File checkIfBackupExists = new File(filepathToChange + ".bak");
            if (!checkIfBackupExists.exists())
                copyFile(filepathToChange, filepathToChange + ".bak");
            copyFile(filepathToChange, filepathToChange + ".tmp");

            RandomAccessFile x = new RandomAccessFile(filepathToChange, "rw");
            x.seek(locationOfChange);

            // Copy section into byte array to write in log
            byte[] removedSection = new byte[virusLength];
            x.read(removedSection, 0, virusLength);
            if (GenerateRandomCorpus.dbg)
                System.out.println(filepathToChange + ":" + locationOfChange);
            x.close();

            // Write changes to log
            byte[] removedSectionConvertedToHexString = StringUtils.getHexString(removedSection).getBytes();
            byte[] virusConvertedToHexString = StringUtils.getHexString(viruses[i]).getBytes();
            byte[] hashConvertedToHexString = StringUtils.getHexString(GenerateRandomViruses.intToByteArray(new String(viruses[i]).hashCode())).getBytes();
            System.out.println(StringUtils.getHexString(removedSection));
            System.out.println(StringUtils.getHexString(viruses[i]));
            logwriter.write(String.format("insert into changes (filepath,loc,dat,vir,hash) values " +
                    "('%s',%d,X'", filepathToChange, locationOfChange).getBytes());
            logwriter.write(removedSectionConvertedToHexString);
            logwriter.write("',X'".getBytes());
            logwriter.write(virusConvertedToHexString);
            logwriter.write("',X'".getBytes());
            logwriter.write(hashConvertedToHexString);
            logwriter.write("');\n".getBytes());

            // Insert virus into file
            File original = new File(filepathToChange);
            original.delete();
            RandomAccessFile fileToInsertIn = new RandomAccessFile(filepathToChange + ".tmp", "rw");
            fileToInsertIn.seek(locationOfChange);
            fileToInsertIn.write(viruses[i]);
            fileToInsertIn.close();

            File a = new File(filepathToChange + ".tmp");
            original = new File(filepathToChange);
            a.renameTo(original);
            a.delete();

            logwriter.close();
        }


    } catch (Exception e)
    {   
        System.err.println(e.toString());
        System.err.println("Error: InsertVirusesIntoCorpus, line 100");
    }
}

有什么想法吗？

Answer 1

我对你的代码感到有点困惑，为什么会有这么多的转换，但是我在这里......

我的直觉告诉我，你有一些字符集转换正在进行，无意中，或者腐败是由于在原始字节，Java字节原语和Java int原语之间移动。请记住，Java byte值范围介于-127和128之间，而String的.getBytes（）是字符编码方案识别。

具体来说，这对我来说真的很奇怪：

byte[] virusConvertedToHexString = StringUtils.getHexString(viruses[i]).getBytes();

这就是发生的事情：

viruses[i]正在为您提供byte数组
StringUtils.getHexString()获取该字节数组，并以byte为单位提供该String数组的十六进制表示形式（假设：这是StringUtils是什么？它似乎没有来自[org.apache.commons.lang][1]。）
最后，您将String的{{1}}数组存储到byte

第二步是我怀疑有问题。

此外，上面的代码块不包含产生的代码：

virusConvertedToHexString

这会有所帮助。

RandomAccessFile.write没有写出我告诉它的内容

1 个答案: