private void PopulateSmallFile(FileEnumeratorParameters parameters, INode node, bool hasFileReadPermissions)
{
_timingMetrics.Start(TimingMetric.ReadingMFTBytes);
byte[] fileBytes = new byte[0];
if (!node.Streams.Any()) //workaround for no file stream such as with hard links
{
try
{
using (FileStream fsSource = new FileStream(FullPath, FileMode.Open, FileAccess.Read))
{
// Read the source file into a byte array.
fileBytes = new byte[fsSource.Length];
int numBytesToRead = (int)fsSource.Length;
int numBytesRead = 0;
while (numBytesToRead > 0)
{
// Read may return anything from 0 to numBytesToRead.
int n = fsSource.Read(fileBytes, numBytesRead, numBytesToRead);
// Break when the end of the file is reached.
if (n == 0)
{
break;
}
numBytesRead += n;
numBytesToRead -= n;
}
numBytesToRead = fileBytes.Length;
}
}
catch (System.IO.IOException ioException)
{
if (ioException.Message.Contains("contains a virus"))
{
string hash = "File access blocked by anti-virus program.";
this.Sha256 = hash;
this.SHA1 = hash;
this.MD5 = hash;
return;
}
}
catch
{ }
}
else
{
fileBytes = node.GetBytes().SelectMany(chunk => chunk).ToArray();
}
_timingMetrics.Stop(TimingMetric.ReadingMFTBytes);
_timingMetrics.Start(TimingMetric.FileHashing);
this._peData = PeDataObject.TryGetPeDataObject(fileBytes);
if (this._peData != null)
{
this.Sha256 = _peData.SHA256Hash;
this.SHA1 = _peData.SHA1Hash;
this.MD5 = _peData.MD5Hash;
}
if (this._peData == null || string.IsNullOrWhiteSpace(this.Sha256))
{
this.Sha256 = Hash.ByteArray.Sha256(fileBytes);
this.SHA1 = Hash.ByteArray.Sha1(fileBytes);
this.MD5 = Hash.ByteArray.MD5(fileBytes);
}
_timingMetrics.Stop(TimingMetric.FileHashing);
_timingMetrics.Start(TimingMetric.MiscFileProperties);
if (_peData != null)
{
_authenticode = AuthenticodeData.GetAuthenticodeData(_peData.Certificate);
}
CancellationHelper.ThrowIfCancelled();
if (hasFileReadPermissions)
{
PopulateFileInfoProperties(FullPath);
}
_timingMetrics.Stop(TimingMetric.MiscFileProperties);
if (hasFileReadPermissions)
{
PopulateShellFileInfo(FullPath);
CancellationHelper.ThrowIfCancelled();
}
YSScanner compiledRules = GetCompiledYaraRules(parameters);
if (compiledRules != null)
{
_timingMetrics.Start(TimingMetric.YaraScanning);
try
{
_yaraRulesMatched = YaraHelper.ScanBytes(fileBytes, compiledRules);
}
catch (Exception ex)
{
parameters.ReportExceptionFunction.Invoke(nameof(PopulateSmallFile), string.Empty, ex);
}
_timingMetrics.Stop(TimingMetric.YaraScanning);
}
CancellationHelper.ThrowIfCancelled();
if (parameters.CalculateEntropy)
{
_timingMetrics.Start(TimingMetric.CalculatingEntropy);
Entropy = EntropyHelper.CalculateFileEntropy(fileBytes);
_timingMetrics.Stop(TimingMetric.CalculatingEntropy);
CancellationHelper.ThrowIfCancelled();
}
}