Split front and back end.

1 files changed, 224 insertions, 0 deletions

diff --git a/BackEnd/Timeline/Services/PasswordService.cs b/BackEnd/Timeline/Services/PasswordService.cs
new file mode 100644
index 00000000..8114a520
--- /dev/null
+++ b/BackEnd/Timeline/Services/PasswordService.cs
@@ -0,0 +1,224 @@
+using Microsoft.AspNetCore.Cryptography.KeyDerivation;

+using System;

+using System.Runtime.CompilerServices;

+using System.Security.Cryptography;

+

+namespace Timeline.Services

+{

+    /// <summary>

+    /// Hashed password is of bad format.

+    /// </summary>

+    /// <seealso cref="IPasswordService.VerifyPassword(string, string)"/>

+    [Serializable]

+    public class HashedPasswordBadFromatException : Exception

+    {

+        private static string MakeMessage(string reason)

+        {

+            return Resources.Services.Exception.HashedPasswordBadFromatException + " Reason: " + reason;

+        }

+

+        public HashedPasswordBadFromatException() : base(Resources.Services.Exception.HashedPasswordBadFromatException) { }

+

+        public HashedPasswordBadFromatException(string message) : base(message) { }

+        public HashedPasswordBadFromatException(string message, Exception inner) : base(message, inner) { }

+

+        public HashedPasswordBadFromatException(string hashedPassword, string reason) : base(MakeMessage(reason)) { HashedPassword = hashedPassword; }

+        public HashedPasswordBadFromatException(string hashedPassword, string reason, Exception inner) : base(MakeMessage(reason), inner) { HashedPassword = hashedPassword; }

+        protected HashedPasswordBadFromatException(

+          System.Runtime.Serialization.SerializationInfo info,

+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }

+

+        public string? HashedPassword { get; set; }

+    }

+

+    public interface IPasswordService

+    {

+        /// <summary>

+        /// Hash a password.

+        /// </summary>

+        /// <param name="password">The password to hash.</param>

+        /// <returns>A hashed representation of the supplied <paramref name="password"/>.</returns>

+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="password"/> is null.</exception>

+        string HashPassword(string password);

+

+        /// <summary>

+        /// Verify whether the password fits into the hashed one.

+        /// 

+        /// Usually you only need to check the returned bool value.

+        /// Catching <see cref="HashedPasswordBadFromatException"/> usually is not necessary.

+        /// Because if your program logic is right and always call <see cref="HashPassword(string)"/>

+        /// and <see cref="VerifyPassword(string, string)"/> in pair, this exception will never be thrown.

+        /// A thrown one usually means the data you saved is corupted, which is a critical problem.

+        /// </summary>

+        /// <param name="hashedPassword">The hashed password.</param>

+        /// <param name="providedPassword">The password supplied for comparison.</param>

+        /// <returns>True indicating password is right. Otherwise false.</returns>

+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="hashedPassword"/> or <paramref name="providedPassword"/> is null.</exception>

+        /// <exception cref="HashedPasswordBadFromatException">Thrown when the hashed password is of bad format.</exception>

+        bool VerifyPassword(string hashedPassword, string providedPassword);

+    }

+

+    /// <summary>

+    /// Copied from https://github.com/aspnet/AspNetCore/blob/master/src/Identity/Extensions.Core/src/PasswordHasher.cs

+    /// Remove V2 format and unnecessary format version check.

+    /// Remove configuration options.

+    /// Remove user related parts.

+    /// Change the exceptions.

+    /// </summary>

+    public class PasswordService : IPasswordService

+    {

+        /* =======================

+        * HASHED PASSWORD FORMATS

+        * =======================

+        * 

+        * Version 3:

+        * PBKDF2 with HMAC-SHA256, 128-bit salt, 256-bit subkey, 10000 iterations.

+        * Format: { 0x01, prf (UInt32), iter count (UInt32), salt length (UInt32), salt, subkey }

+        * (All UInt32s are stored big-endian.)

+        */

+

+        private readonly RandomNumberGenerator _rng = RandomNumberGenerator.Create();

+

+        public PasswordService()

+        {

+        }

+

+        // Compares two byte arrays for equality. The method is specifically written so that the loop is not optimized.

+        [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.NoOptimization)]

+        private static bool ByteArraysEqual(byte[] a, byte[] b)

+        {

+            if (a == null && b == null)

+            {

+                return true;

+            }

+            if (a == null || b == null || a.Length != b.Length)

+            {

+                return false;

+            }

+            var areSame = true;

+            for (var i = 0; i < a.Length; i++)

+            {

+                areSame &= (a[i] == b[i]);

+            }

+            return areSame;

+        }

+

+        public string HashPassword(string password)

+        {

+            if (password == null)

+                throw new ArgumentNullException(nameof(password));

+            return Convert.ToBase64String(HashPasswordV3(password, _rng));

+        }

+

+        private static byte[] HashPasswordV3(string password, RandomNumberGenerator rng)

+        {

+            return HashPasswordV3(password, rng,

+                prf: KeyDerivationPrf.HMACSHA256,

+                iterCount: 10000,

+                saltSize: 128 / 8,

+                numBytesRequested: 256 / 8);

+        }

+

+        private static byte[] HashPasswordV3(string password, RandomNumberGenerator rng, KeyDerivationPrf prf, int iterCount, int saltSize, int numBytesRequested)

+        {

+            // Produce a version 3 (see comment above) text hash.

+            byte[] salt = new byte[saltSize];

+            rng.GetBytes(salt);

+            byte[] subkey = KeyDerivation.Pbkdf2(password, salt, prf, iterCount, numBytesRequested);

+

+            var outputBytes = new byte[13 + salt.Length + subkey.Length];

+            outputBytes[0] = 0x01; // format marker

+            WriteNetworkByteOrder(outputBytes, 1, (uint)prf);

+            WriteNetworkByteOrder(outputBytes, 5, (uint)iterCount);

+            WriteNetworkByteOrder(outputBytes, 9, (uint)saltSize);

+            Buffer.BlockCopy(salt, 0, outputBytes, 13, salt.Length);

+            Buffer.BlockCopy(subkey, 0, outputBytes, 13 + saltSize, subkey.Length);

+            return outputBytes;

+        }

+

+        public bool VerifyPassword(string hashedPassword, string providedPassword)

+        {

+            if (hashedPassword == null)

+                throw new ArgumentNullException(nameof(hashedPassword));

+            if (providedPassword == null)

+                throw new ArgumentNullException(nameof(providedPassword));

+

+            byte[] decodedHashedPassword;

+            try

+            {

+                decodedHashedPassword = Convert.FromBase64String(hashedPassword);

+            }

+            catch (FormatException e)

+            {

+                throw new HashedPasswordBadFromatException(hashedPassword, Resources.Services.Exception.HashedPasswordBadFromatExceptionNotBase64, e);

+            }

+

+            // read the format marker from the hashed password

+            if (decodedHashedPassword.Length == 0)

+            {

+                throw new HashedPasswordBadFromatException(hashedPassword, Resources.Services.Exception.HashedPasswordBadFromatExceptionNotLength0);

+            }

+

+            return (decodedHashedPassword[0]) switch

+            {

+                0x01 => VerifyHashedPasswordV3(decodedHashedPassword, providedPassword, hashedPassword),

+                _ => throw new HashedPasswordBadFromatException(hashedPassword, Resources.Services.Exception.HashedPasswordBadFromatExceptionNotUnknownMarker),

+            };

+        }

+

+        private static bool VerifyHashedPasswordV3(byte[] hashedPassword, string password, string hashedPasswordString)

+        {

+            try

+            {

+                // Read header information

+                KeyDerivationPrf prf = (KeyDerivationPrf)ReadNetworkByteOrder(hashedPassword, 1);

+                int iterCount = (int)ReadNetworkByteOrder(hashedPassword, 5);

+                int saltLength = (int)ReadNetworkByteOrder(hashedPassword, 9);

+

+                // Read the salt: must be >= 128 bits

+                if (saltLength < 128 / 8)

+                {

+                    throw new HashedPasswordBadFromatException(hashedPasswordString, Resources.Services.Exception.HashedPasswordBadFromatExceptionNotSaltTooShort);

+                }

+                byte[] salt = new byte[saltLength];

+                Buffer.BlockCopy(hashedPassword, 13, salt, 0, salt.Length);

+

+                // Read the subkey (the rest of the payload): must be >= 128 bits

+                int subkeyLength = hashedPassword.Length - 13 - salt.Length;

+                if (subkeyLength < 128 / 8)

+                {

+                    throw new HashedPasswordBadFromatException(hashedPasswordString, Resources.Services.Exception.HashedPasswordBadFromatExceptionNotSubkeyTooShort);

+                }

+                byte[] expectedSubkey = new byte[subkeyLength];

+                Buffer.BlockCopy(hashedPassword, 13 + salt.Length, expectedSubkey, 0, expectedSubkey.Length);

+

+                // Hash the incoming password and verify it

+                byte[] actualSubkey = KeyDerivation.Pbkdf2(password, salt, prf, iterCount, subkeyLength);

+                return ByteArraysEqual(actualSubkey, expectedSubkey);

+            }

+            catch (Exception e)

+            {

+                // This should never occur except in the case of a malformed payload, where

+                // we might go off the end of the array. Regardless, a malformed payload

+                // implies verification failed.

+                throw new HashedPasswordBadFromatException(hashedPasswordString, Resources.Services.Exception.HashedPasswordBadFromatExceptionNotOthers, e);

+            }

+        }

+

+        private static uint ReadNetworkByteOrder(byte[] buffer, int offset)

+        {

+            return ((uint)(buffer[offset + 0]) << 24)

+                | ((uint)(buffer[offset + 1]) << 16)

+                | ((uint)(buffer[offset + 2]) << 8)

+                | ((uint)(buffer[offset + 3]));

+        }

+

+        private static void WriteNetworkByteOrder(byte[] buffer, int offset, uint value)

+        {

+            buffer[offset + 0] = (byte)(value >> 24);

+            buffer[offset + 1] = (byte)(value >> 16);

+            buffer[offset + 2] = (byte)(value >> 8);

+            buffer[offset + 3] = (byte)(value >> 0);

+        }

+    }

+}