:3

2026-08-24 17:00:26 -04:00
parent cc1148050c
commit 42f7f57b72
401 changed files with 1108081 additions and 0 deletions
@@ -0,0 +1,123 @@
+using System.Security.Cryptography;
+using System.Text.Json;
+
+namespace Mocha2023.Classes
+{
+
+    public sealed class ImageSigner : IDisposable
+    {
+        private static readonly Lazy<ImageSigner> SharedInstance =
+            new(() => LoadFromDataDirectory(), LazyThreadSafetyMode.ExecutionAndPublication);
+
+        private readonly RSA _rsa;
+        private readonly object _signLock = new();
+
+        private ImageSigner(RSAParameters parameters)
+        {
+            _rsa = RSA.Create();
+            _rsa.ImportParameters(parameters);
+        }
+
+        public static ImageSigner Shared => SharedInstance.Value;
+
+        public byte[] SignImage(byte[] image)
+        {
+            ArgumentNullException.ThrowIfNull(image);
+
+            lock (_signLock)
+            {
+                return _rsa.SignData(
+                    image,
+                    HashAlgorithmName.SHA1,
+                    RSASignaturePadding.Pkcs1);
+            }
+        }
+
+        public void Dispose()
+        {
+            _rsa.Dispose();
+        }
+
+        private static ImageSigner LoadFromDataDirectory()
+        {
+            string path = Path.Combine(Program.dataDir, "ImageRSAParams.json");
+            if (!File.Exists(path))
+            {
+                throw new FileNotFoundException(
+                    "Image signing key was not found. Expected Data/ImageRSAParams.json.",
+                    path);
+            }
+
+            ImageRsaParameters? stored;
+            try
+            {
+                stored = JsonSerializer.Deserialize<ImageRsaParameters>(
+                    File.ReadAllText(path),
+                    new JsonSerializerOptions
+                    {
+                        PropertyNameCaseInsensitive = true
+                    });
+            }
+            catch (Exception ex) when (
+                ex is JsonException or FormatException or IOException)
+            {
+                throw new InvalidDataException(
+                    "Data/ImageRSAParams.json is not a valid RSA private key.",
+                    ex);
+            }
+
+            if (stored == null)
+                throw new InvalidDataException("The image signing key is empty.");
+
+            try
+            {
+                return new ImageSigner(new RSAParameters
+                {
+                    Modulus = Decode(stored.Modulus, nameof(stored.Modulus)),
+                    Exponent = Decode(stored.Exponent, nameof(stored.Exponent)),
+                    P = Decode(stored.P, nameof(stored.P)),
+                    Q = Decode(stored.Q, nameof(stored.Q)),
+                    DP = Decode(stored.DP, nameof(stored.DP)),
+                    DQ = Decode(stored.DQ, nameof(stored.DQ)),
+                    InverseQ = Decode(stored.InverseQ, nameof(stored.InverseQ)),
+                    D = Decode(stored.D, nameof(stored.D))
+                });
+            }
+            catch (CryptographicException ex)
+            {
+                throw new InvalidDataException(
+                    "Data/ImageRSAParams.json contains inconsistent RSA parameters.",
+                    ex);
+            }
+        }
+
+        private static byte[] Decode(string? value, string field)
+        {
+            if (string.IsNullOrWhiteSpace(value))
+                throw new InvalidDataException($"Image RSA field {field} is missing.");
+
+            try
+            {
+                return Convert.FromBase64String(value);
+            }
+            catch (FormatException ex)
+            {
+                throw new InvalidDataException(
+                    $"Image RSA field {field} is not valid Base64.",
+                    ex);
+            }
+        }
+
+        private sealed class ImageRsaParameters
+        {
+            public string? Modulus { get; set; }
+            public string? Exponent { get; set; }
+            public string? P { get; set; }
+            public string? Q { get; set; }
+            public string? DP { get; set; }
+            public string? DQ { get; set; }
+            public string? InverseQ { get; set; }
+            public string? D { get; set; }
+        }
+    }
+}