1 files changed, 120 insertions, 0 deletions
diff --git a/Jellyfin.Server.Implementations/Users/DefaultAuthenticationProvider.cs b/Jellyfin.Server.Implementations/Users/DefaultAuthenticationProvider.cs
new file mode 100644
index 000000000..f79e433a6
--- /dev/null
+++ b/Jellyfin.Server.Implementations/Users/DefaultAuthenticationProvider.cs
@@ -0,0 +1,120 @@
+#nullable enable
+
+using System;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Jellyfin.Data.Entities;
+using MediaBrowser.Common.Cryptography;
+using MediaBrowser.Controller.Authentication;
+using MediaBrowser.Model.Cryptography;
+
+namespace Jellyfin.Server.Implementations.Users
+{
+    /// <summary>
+    /// The default authentication provider.
+    /// </summary>
+    public class DefaultAuthenticationProvider : IAuthenticationProvider, IRequiresResolvedUser
+    {
+        private readonly ICryptoProvider _cryptographyProvider;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DefaultAuthenticationProvider"/> class.
+        /// </summary>
+        /// <param name="cryptographyProvider">The cryptography provider.</param>
+        public DefaultAuthenticationProvider(ICryptoProvider cryptographyProvider)
+        {
+            _cryptographyProvider = cryptographyProvider;
+        }
+
+        /// <inheritdoc />
+        public string Name => "Default";
+
+        /// <inheritdoc />
+        public bool IsEnabled => true;
+
+        /// <inheritdoc />
+        // This is dumb and an artifact of the backwards way auth providers were designed.
+        // This version of authenticate was never meant to be called, but needs to be here for interface compat
+        // Only the providers that don't provide local user support use this
+        public Task<ProviderAuthenticationResult> Authenticate(string username, string password)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        // This is the version that we need to use for local users. Because reasons.
+        public Task<ProviderAuthenticationResult> Authenticate(string username, string password, User resolvedUser)
+        {
+            if (resolvedUser == null)
+            {
+                throw new AuthenticationException("Specified user does not exist.");
+            }
+
+            bool success = false;
+
+            // As long as jellyfin supports passwordless users, we need this little block here to accommodate
+            if (!HasPassword(resolvedUser) && string.IsNullOrEmpty(password))
+            {
+                return Task.FromResult(new ProviderAuthenticationResult
+                {
+                    Username = username
+                });
+            }
+
+            // Handle the case when the stored password is null, but the user tried to login with a password
+            if (resolvedUser.Password != null)
+            {
+                byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
+
+                PasswordHash readyHash = PasswordHash.Parse(resolvedUser.Password);
+                if (_cryptographyProvider.GetSupportedHashMethods().Contains(readyHash.Id)
+                    || _cryptographyProvider.DefaultHashMethod == readyHash.Id)
+                {
+                    byte[] calculatedHash = _cryptographyProvider.ComputeHash(
+                        readyHash.Id,
+                        passwordBytes,
+                        readyHash.Salt.ToArray());
+
+                    if (readyHash.Hash.SequenceEqual(calculatedHash))
+                    {
+                        success = true;
+                    }
+                }
+                else
+                {
+                    throw new AuthenticationException($"Requested crypto method not available in provider: {readyHash.Id}");
+                }
+            }
+
+            if (!success)
+            {
+                throw new AuthenticationException("Invalid username or password");
+            }
+
+            return Task.FromResult(new ProviderAuthenticationResult
+            {
+                Username = username
+            });
+        }
+
+        /// <inheritdoc />
+        public bool HasPassword(User user)
+            => !string.IsNullOrEmpty(user?.Password);
+
+        /// <inheritdoc />
+        public Task ChangePassword(User user, string newPassword)
+        {
+            if (string.IsNullOrEmpty(newPassword))
+            {
+                user.Password = null;
+                return Task.CompletedTask;
+            }
+
+            PasswordHash newPasswordHash = _cryptographyProvider.CreatePasswordHash(newPassword);
+            user.Password = newPasswordHash.ToString();
+
+            return Task.CompletedTask;
+        }
+    }
+}