(bugfix): add remove padding, code review
This commit is contained in:
parent
225debf8f2
commit
8c4da33531
@ -244,27 +244,7 @@ public class Application {
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});
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}
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private static byte[] AddPadding(byte[] data, int blockSize) {
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// Calculate the padding size
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int paddingSize = blockSize - (data.Length % blockSize);
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if (paddingSize == blockSize) {
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paddingSize = 0;
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}
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// Create a new array with the original data plus padding
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byte[] paddedData = new byte[data.Length + paddingSize + 1];
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Array.Copy(data, paddedData, data.Length);
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// Fill the padding with a specific value (e.g., 0x00)
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for (int i = data.Length; i < paddedData.Length - 1; i++) {
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paddedData[i] = 0x00;
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}
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// Append the padding size at the end
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paddedData[paddedData.Length - 1] = (byte)paddingSize;
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return paddedData;
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}
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private void WriteFilesToTape(WorkingFolder workingFolder, string descriptorFilePath, uint blockSize) {
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PathAccessWrapper(workingFolder, (directoryPath) => {
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@ -334,7 +314,7 @@ public class Application {
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var encryptedDescriptorData = AESGCMUtility.EncryptData(descriptorData, _secret);
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// add padding to the encrypted descriptor data
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var paddedDescriptorData = AddPadding(encryptedDescriptorData, (int)blockSize);
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var paddedDescriptorData = PaddingUtility.AddPadding(encryptedDescriptorData, (int)blockSize);
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// calculate the number of blocks needed
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var descriptorBlocks = (paddedDescriptorData.Length + blockSize - 1) / blockSize;
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@ -381,55 +361,53 @@ public class Application {
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handler.SetPosition(TapeDeviceHandler.TAPE_SPACE_FILEMARKS, 0, 1);
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Thread.Sleep(2000);
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var position = handler.GetPosition(TapeDeviceHandler.TAPE_ABSOLUTE_BLOCK);
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if (position.Error != null)
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var endOfBackupMarkerPosition = handler.GetPosition(TapeDeviceHandler.TAPE_ABSOLUTE_BLOCK);
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if (endOfBackupMarkerPosition.Error != null || endOfBackupMarkerPosition.OffsetLow == null)
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return null;
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var desctiptorBlocks = position.OffsetLow;
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_logger.LogInformation($"End of backup marker position: {endOfBackupMarkerPosition.OffsetLow}");
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var descriptorBlocks = endOfBackupMarkerPosition.OffsetLow;
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handler.SetPosition(TapeDeviceHandler.TAPE_SPACE_FILEMARKS, 0, 2);
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Thread.Sleep(2000);
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position = handler.GetPosition(TapeDeviceHandler.TAPE_ABSOLUTE_BLOCK);
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if (position.Error != null)
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var endOfDescriptorMarkerPosition = handler.GetPosition(TapeDeviceHandler.TAPE_ABSOLUTE_BLOCK);
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if (endOfDescriptorMarkerPosition.Error != null || endOfDescriptorMarkerPosition.OffsetLow == null)
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return null;
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desctiptorBlocks = position.OffsetLow - desctiptorBlocks;
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_logger.LogInformation($"End of descriptor marker position: {endOfDescriptorMarkerPosition.OffsetLow}");
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descriptorBlocks = endOfDescriptorMarkerPosition.OffsetLow - descriptorBlocks;
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var padding = handler.ReadData(blockSize);
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if (descriptorBlocks == null)
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return null;
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handler.SetPosition(TapeDeviceHandler.TAPE_SPACE_FILEMARKS, 0, 1);
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_logger.LogInformation($"Descriptor blocks to read: {descriptorBlocks}");
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handler.SetPosition(TapeDeviceHandler.TAPE_ABSOLUTE_BLOCK, 0, (long)(endOfDescriptorMarkerPosition.OffsetLow - descriptorBlocks));
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Thread.Sleep(2000);
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// read data from descriptorBlocks
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var buffer = new List<byte>();
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for (var i = 0; i < desctiptorBlocks; i++) {
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var data = handler.ReadData(blockSize);
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buffer.AddRange(data);
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descriptorBlocks -= 2;
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var paddedData = new byte[(descriptorBlocks.Value) * blockSize];
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var buffer = new byte[blockSize];
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for (var i = 0; i < descriptorBlocks; i++) {
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var bytesRead = handler.ReadData(buffer, 0, buffer.Length);
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// Copy the read data into the encryptedData array
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Array.Copy(buffer, 0, paddedData, i * blockSize, buffer.Length);
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}
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// Convert buffer to array
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var paddedData = buffer.ToArray();
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// i need to remove padding from the data
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var encryptedData = PaddingUtility.RemovePadding(paddedData, (int)blockSize);
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// Retrieve the padding size from the last byte
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int paddingSize = paddedData[^1];
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// Calculate the length of the original data
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int originalDataLength = paddedData.Length - paddingSize - 1;
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// Ensure the padding size is valid
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if (paddingSize < 0 || paddingSize >= paddedData.Length || originalDataLength < 0)
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return null;
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// Create a new array for the original data
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var descriptorData = new byte[originalDataLength];
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Array.Copy(paddedData, descriptorData, originalDataLength);
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descriptorData = AESGCMUtility.DecryptData(descriptorData, _secret);
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// decrypt the data
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var decryptedData = AESGCMUtility.DecryptData(encryptedData, _secret);
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// Convert byte array to string and trim ending zeros
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var json = Encoding.UTF8.GetString(descriptorData);
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var json = Encoding.UTF8.GetString(decryptedData);
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try {
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var descriptor = JsonSerializer.Deserialize<BackupDescriptor>(json);
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@ -514,7 +492,7 @@ public class Application {
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var encryptedDescriptorData = AESGCMUtility.EncryptData(File.ReadAllBytes(_descriptorFilePath), _secret);
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var paddedDescriptorData = AddPadding(encryptedDescriptorData, (int)descriptor.BlockSize);
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var paddedDescriptorData = PaddingUtility.AddPadding(encryptedDescriptorData, (int)descriptor.BlockSize);
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const ulong fileMarkBlocks = 2;
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87
src/MaksIT.LTO.Core/Crc32.cs
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87
src/MaksIT.LTO.Core/Crc32.cs
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@ -0,0 +1,87 @@
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using System.Security.Cryptography;
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namespace MaksIT.LTO.Core;
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public class Crc32 : HashAlgorithm {
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public const uint DefaultPolynomial = 0xedb88320;
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public const uint DefaultSeed = 0xffffffff;
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private static uint[]? defaultTable;
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private readonly uint seed;
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private readonly uint[] table;
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private uint hash;
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public Crc32()
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: this(DefaultPolynomial, DefaultSeed) {
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}
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public Crc32(uint polynomial, uint seed) {
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table = InitializeTable(polynomial);
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this.seed = hash = seed;
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}
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public override void Initialize() {
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hash = seed;
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}
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protected override void HashCore(byte[] buffer, int start, int length) {
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hash = CalculateHash(table, hash, buffer, start, length);
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}
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protected override byte[] HashFinal() {
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var hashBuffer = UInt32ToBigEndianBytes(~hash);
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HashValue = hashBuffer;
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return hashBuffer;
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}
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public override int HashSize => 32;
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public static uint Compute(byte[] buffer) {
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return Compute(DefaultPolynomial, DefaultSeed, buffer);
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}
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public static uint Compute(uint seed, byte[] buffer) {
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return Compute(DefaultPolynomial, seed, buffer);
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}
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public static uint Compute(uint polynomial, uint seed, byte[] buffer) {
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return ~CalculateHash(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
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}
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private static uint[] InitializeTable(uint polynomial) {
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if (polynomial == DefaultPolynomial && defaultTable != null)
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return defaultTable;
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var createTable = new uint[256];
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for (var i = 0; i < 256; i++) {
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var entry = (uint)i;
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for (var j = 0; j < 8; j++)
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if ((entry & 1) == 1)
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entry = (entry >> 1) ^ polynomial;
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else
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entry >>= 1;
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createTable[i] = entry;
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}
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if (polynomial == DefaultPolynomial)
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defaultTable = createTable;
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return createTable;
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}
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private static uint CalculateHash(uint[] table, uint seed, byte[] buffer, int start, int size) {
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var crc = seed;
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for (var i = start; i < size - start; i++)
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crc = (crc >> 8) ^ table[buffer[i] ^ crc & 0xff];
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return crc;
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}
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private static byte[] UInt32ToBigEndianBytes(uint x) => [
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(byte)((x >> 24) & 0xff),
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(byte)((x >> 16) & 0xff),
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(byte)((x >> 8) & 0xff),
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(byte)(x & 0xff)
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];
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}
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@ -1,33 +0,0 @@
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using System.Diagnostics;
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namespace MaksIT.LTO.Core;
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public class DriverManager {
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public static void RestartDriver(string deviceName) {
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string script = $@"
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$device = Get-PnpDevice -FriendlyName '{deviceName}'
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Disable-PnpDevice -InstanceId $device.InstanceId -Confirm:$false
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Start-Sleep -Seconds 5
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Enable-PnpDevice -InstanceId $device.InstanceId -Confirm:$false
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";
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ProcessStartInfo psi = new ProcessStartInfo {
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FileName = "powershell.exe",
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Arguments = $"-NoProfile -ExecutionPolicy Bypass -Command \"{script}\"",
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UseShellExecute = false,
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RedirectStandardOutput = true,
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RedirectStandardError = true
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};
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using (Process process = Process.Start(psi)) {
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string output = process.StandardOutput.ReadToEnd();
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string error = process.StandardError.ReadToEnd();
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process.WaitForExit();
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Console.WriteLine(output);
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if (!string.IsNullOrEmpty(error)) {
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Console.WriteLine($"Error: {error}");
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}
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}
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}
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}
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@ -1,19 +1,16 @@
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using System.IO;
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using System.Security.Cryptography;
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namespace MaksIT.LTO.Core.Helpers;
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namespace MaksIT.LTO.Core.Helpers;
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public static class ChecksumUtility {
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public static string CalculateCRC32Checksum(byte[] data) {
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using var crc32 = new Crc32();
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byte[] hashBytes = crc32.ComputeHash(data);
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var hashBytes = crc32.ComputeHash(data);
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return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();
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}
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public static string CalculateCRC32ChecksumFromFile(string filePath) {
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using var crc32 = new Crc32();
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using var stream = File.OpenRead(filePath);
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byte[] hashBytes = crc32.ComputeHash(stream);
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var hashBytes = crc32.ComputeHash(stream);
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return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();
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}
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@ -26,105 +23,23 @@ public static class ChecksumUtility {
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crc32.TransformBlock(buffer, 0, bytesRead, null, 0);
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}
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crc32.TransformFinalBlock(buffer, 0, 0);
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byte[] hashBytes = crc32.Hash;
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return BitConverter.ToString(hashBytes).Replace("-", "").ToLower();
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var hashBytes = crc32.Hash;
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return BitConverter.ToString(hashBytes ?? Array.Empty<byte>()).Replace("-", "").ToLower();
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}
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public static bool VerifyCRC32Checksum(byte[] data, string expectedChecksum) {
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string calculatedChecksum = CalculateCRC32Checksum(data);
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var calculatedChecksum = CalculateCRC32Checksum(data);
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return string.Equals(calculatedChecksum, expectedChecksum, StringComparison.OrdinalIgnoreCase);
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}
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public static bool VerifyCRC32ChecksumFromFile(string filePath, string expectedChecksum) {
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string calculatedChecksum = CalculateCRC32ChecksumFromFile(filePath);
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var calculatedChecksum = CalculateCRC32ChecksumFromFile(filePath);
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return string.Equals(calculatedChecksum, expectedChecksum, StringComparison.OrdinalIgnoreCase);
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}
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public static bool VerifyCRC32ChecksumFromFileInChunks(string filePath, string expectedChecksum, int chunkSize = 8192) {
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string calculatedChecksum = CalculateCRC32ChecksumFromFileInChunks(filePath, chunkSize);
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var calculatedChecksum = CalculateCRC32ChecksumFromFileInChunks(filePath, chunkSize);
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return string.Equals(calculatedChecksum, expectedChecksum, StringComparison.OrdinalIgnoreCase);
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}
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}
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public class Crc32 : HashAlgorithm {
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public const uint DefaultPolynomial = 0xedb88320;
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public const uint DefaultSeed = 0xffffffff;
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private static uint[]? defaultTable;
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private readonly uint seed;
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private readonly uint[] table;
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private uint hash;
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public Crc32()
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: this(DefaultPolynomial, DefaultSeed) {
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}
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public Crc32(uint polynomial, uint seed) {
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table = InitializeTable(polynomial);
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this.seed = hash = seed;
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}
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public override void Initialize() {
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hash = seed;
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}
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protected override void HashCore(byte[] buffer, int start, int length) {
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hash = CalculateHash(table, hash, buffer, start, length);
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}
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protected override byte[] HashFinal() {
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var hashBuffer = UInt32ToBigEndianBytes(~hash);
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HashValue = hashBuffer;
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return hashBuffer;
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}
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public override int HashSize => 32;
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public static uint Compute(byte[] buffer) {
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return Compute(DefaultPolynomial, DefaultSeed, buffer);
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}
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public static uint Compute(uint seed, byte[] buffer) {
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return Compute(DefaultPolynomial, seed, buffer);
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}
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public static uint Compute(uint polynomial, uint seed, byte[] buffer) {
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return ~CalculateHash(InitializeTable(polynomial), seed, buffer, 0, buffer.Length);
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}
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private static uint[] InitializeTable(uint polynomial) {
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if (polynomial == DefaultPolynomial && defaultTable != null)
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return defaultTable;
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var createTable = new uint[256];
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for (var i = 0; i < 256; i++) {
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var entry = (uint)i;
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for (var j = 0; j < 8; j++)
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if ((entry & 1) == 1)
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entry = (entry >> 1) ^ polynomial;
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else
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entry >>= 1;
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createTable[i] = entry;
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}
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if (polynomial == DefaultPolynomial)
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defaultTable = createTable;
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return createTable;
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}
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private static uint CalculateHash(uint[] table, uint seed, byte[] buffer, int start, int size) {
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var crc = seed;
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for (var i = start; i < size - start; i++)
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crc = (crc >> 8) ^ table[buffer[i] ^ crc & 0xff];
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return crc;
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}
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private static byte[] UInt32ToBigEndianBytes(uint x) => [
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(byte)((x >> 24) & 0xff),
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(byte)((x >> 16) & 0xff),
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(byte)((x >> 8) & 0xff),
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(byte)(x & 0xff)
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];
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}
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38
src/MaksIT.LTO.Core/Utilities/PaddingUtility.cs
Normal file
38
src/MaksIT.LTO.Core/Utilities/PaddingUtility.cs
Normal file
@ -0,0 +1,38 @@
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namespace MaksIT.LTO.Core.Utilities;
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public static class PaddingUtility {
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private const byte _specialByte = 0x80;
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public static byte[] AddPadding(byte[] data, int blockSize) {
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var paddingSize = blockSize - (data.Length % blockSize);
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if (paddingSize == blockSize) {
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paddingSize = 0; // no padding needed if already aligned
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}
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var paddedData = new byte[data.Length + paddingSize];
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Array.Copy(data, paddedData, data.Length);
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// fill the padding bytes with specialBytes
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for (var i = data.Length; i < paddedData.Length; i++) {
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paddedData[i] = _specialByte;
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}
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return paddedData;
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}
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public static byte[] RemovePadding(byte[] paddedData, int blockSize) {
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var originalLength = paddedData.Length;
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// find the original length by checking for the padding byte 0x80
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while (originalLength > 0 && paddedData[originalLength - 1] == _specialByte) {
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originalLength--;
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}
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// create a new array to hold the unpadded data
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var unpaddedData = new byte[originalLength];
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Array.Copy(paddedData, unpaddedData, originalLength);
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return unpaddedData;
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}
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}
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