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大家好。我正在从一个 sql 格式文件读取到另一个文件，中间的两个字节已损坏，我认为这是我没有做的一些准备或保护措施。

损坏数据示例：

//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");
    }
}

有任何想法吗？

4

1 回答 1

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我对您的代码以及为什么要进行如此多的转换感到有些困惑，但是我走了...

我的直觉告诉我，您要么无意中进行了一些字符集转换，要么是由于在原始字节、Java 字节原语和 Java int 原语之间移动造成的损坏。请记住，Java 的byte值范围在 -127 和 128 之间，并且 String 的 .getBytes() 可以识别字符编码方案。

具体来说，这对我来说真的很奇怪：

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

这是正在发生的事情：

  1. viruses[i]给你一个byte数组
  2. StringUtils.getHexString()byte获取该字节数组并为您提供该数组的十六进制表示形式String（假设：这是什么StringUtils？它似乎不是来自[org.apache.commons.lang][1]。）
  3. 最后，您将String'sbyte数组存储到virusConvertedToHexString

第 2 步是我会怀疑麻烦。

此外，上面的代码块不包括生成的代码：

//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');

这会有所帮助。

于 2009-07-08T09:31:37.267 回答