IW4M-Admin/Application/Misc/RemoteAssemblyHandler.cs
2023-05-28 11:38:57 -05:00

77 lines
2.9 KiB
C#

using SharedLibraryCore.Configuration;
using SharedLibraryCore.Interfaces;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;
using Microsoft.Extensions.Logging;
using ILogger = Microsoft.Extensions.Logging.ILogger;
namespace IW4MAdmin.Application.Misc
{
public class RemoteAssemblyHandler : IRemoteAssemblyHandler
{
private const int KeyLength = 32;
private const int TagLength = 16;
private const int NonceLength = 12;
private const int IterationCount = 10000;
private readonly ApplicationConfiguration _appconfig;
private readonly ILogger _logger;
public RemoteAssemblyHandler(ILogger<RemoteAssemblyHandler> logger, ApplicationConfiguration appconfig)
{
_appconfig = appconfig;
_logger = logger;
}
public IEnumerable<Assembly> DecryptAssemblies(string[] encryptedAssemblies)
{
return DecryptContent(encryptedAssemblies)
.Select(Assembly.Load);
}
public IEnumerable<string> DecryptScripts(string[] encryptedScripts)
{
return DecryptContent(encryptedScripts).Select(decryptedScript => Encoding.UTF8.GetString(decryptedScript));
}
private IEnumerable<byte[]> DecryptContent(string[] content)
{
if (string.IsNullOrEmpty(_appconfig.Id) || string.IsNullOrWhiteSpace(_appconfig.SubscriptionId))
{
_logger.LogWarning($"{nameof(_appconfig.Id)} and {nameof(_appconfig.SubscriptionId)} must be provided to attempt loading remote assemblies/scripts");
return Array.Empty<byte[]>();
}
var assemblies = content.Select(piece =>
{
var byteContent = Convert.FromBase64String(piece);
var encryptedContent = byteContent.Take(byteContent.Length - (TagLength + NonceLength)).ToArray();
var tag = byteContent.Skip(byteContent.Length - (TagLength + NonceLength)).Take(TagLength).ToArray();
var nonce = byteContent.Skip(byteContent.Length - NonceLength).Take(NonceLength).ToArray();
var decryptedContent = new byte[encryptedContent.Length];
var keyGen = new Rfc2898DeriveBytes(Encoding.UTF8.GetBytes(_appconfig.SubscriptionId), Encoding.UTF8.GetBytes(_appconfig.Id), IterationCount, HashAlgorithmName.SHA512);
var encryption = new AesGcm(keyGen.GetBytes(KeyLength));
try
{
encryption.Decrypt(nonce, encryptedContent, tag, decryptedContent);
}
catch (CryptographicException ex)
{
_logger.LogError(ex, "Could not decrypt remote plugin assemblies");
}
return decryptedContent;
});
return assemblies.ToArray();
}
}
}