Added basic infrastructure for JWT authentication

4 files changed, 100 insertions, 0 deletions

diff --git a/Controllers/ApiLoginController.cs b/Controllers/ApiLoginController.cs
new file mode 100644
index 0000000..fdf9bae
--- /dev/null
+++ b/Controllers/ApiLoginController.cs
@@ -0,0 +1,46 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.IdentityModel.Tokens;
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Security.Cryptography;
+
+namespace HyperBooru.Controllers;
+
+[ApiController]
+[Route("/api/auth")]
+public class ApiLoginController : Controller {
+    private readonly RSA rsa;
+
+    public ApiLoginController(RSA rsa) =>
+        this.rsa = rsa;
+
+    [HttpPost]
+    public IActionResult Login([FromBody] LoginRequest request) {
+        var claims = new[] {
+            new Claim(ClaimTypes.Name, request.Username),
+            // TODO: Populate with the user's actual GUID
+            new Claim("uid", Guid.Empty.ToString().ToLower()),
+            new Claim("nsfw", request.NsfwClaim.ToString().ToLower())
+        };
+
+        var creds = new SigningCredentials(
+            new RsaSecurityKey(rsa),
+            SecurityAlgorithms.RsaSha256);
+
+        var token = new JwtSecurityToken(
+            claims: claims,
+            expires: DateTime.UtcNow.AddDays(30),
+            signingCredentials: creds);
+
+        var jwt = new JwtSecurityTokenHandler().WriteToken(token);
+
+        return Ok(new { token = jwt });
+    }
+
+    public record LoginRequest {
+        public required string Username { get; set; }
+        public required string Password { get; set; }
+
+        public bool NsfwClaim { get; set; } = false;
+    }
+}
diff --git a/Enum.cs b/Enum.cs
new file mode 100644
index 0000000..20e384c
--- /dev/null
+++ b/Enum.cs
@@ -0,0 +1,5 @@
+namespace HyperBooru.Server;
+
+public static class AuthorizationPolicy {
+    public const string NsfwPolicy = "IsNsfw";
+}
diff --git a/Program.cs b/Program.cs
index 1694587..2c56209 100644
--- a/Program.cs
+++ b/Program.cs
@@ -1,8 +1,11 @@
 using HyperBooru.Server.Components;
 using HyperBooru.Services;
+using Microsoft.AspNetCore.Authentication.JwtBearer;
 using Microsoft.AspNetCore.DataProtection;
 using Microsoft.AspNetCore.Http.Json;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.IdentityModel.Tokens;
+using System.Security.Cryptography;
 using System.Text.Json.Serialization;
 
 namespace HyperBooru.Server;
@@ -39,6 +42,47 @@ public class Program {
                     .GetRequiredService<IConfigService>()
                     .KeyPath));
 
+        // Load our persistently-stored JWT signing key
+        builder.Services.AddSingleton<RSA>(sp => {
+            var keyPath = Path.Combine(
+                sp.GetRequiredService<IConfigService>().KeyPath,
+                "jwt_key");
+
+            var protector = sp.GetRequiredService<IDataProtectionProvider>()
+                .CreateProtector("jwt-signing-key");
+
+            try {
+                var unprotected = protector.Unprotect(File.ReadAllBytes(keyPath));
+                var rsa = RSA.Create();
+                rsa.ImportRSAPrivateKey(unprotected, out var _);
+                return rsa;
+            } catch {
+                var rsa = RSA.Create(4096);
+                var privKey = rsa.ExportRSAPrivateKey();
+                File.WriteAllBytes(keyPath, protector.Protect(privKey));
+                return rsa;
+            }
+        });
+
+        // Configure JWT token-based authentication
+        builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
+            .AddJwtBearer(o => {
+                var rsa = builder.Services.BuildServiceProvider().GetRequiredService<RSA>();
+                o.TokenValidationParameters  = new TokenValidationParameters {
+                    ValidateIssuer           = false,
+                    ValidateAudience         = false,
+                    ValidateIssuerSigningKey = true,
+                    IssuerSigningKey         = new RsaSecurityKey(rsa)
+                };
+            });
+
+        // Configure custom authorization policies
+        builder.Services.AddAuthorization(o => {
+            o.AddPolicy(AuthorizationPolicy.NsfwPolicy, p => {
+                p.RequireClaim("nsfw", "true");
+            });
+        });
+
         var app = builder.Build();
 
         // Ensure database is created and it's schema is up to date
@@ -52,6 +96,8 @@ public class Program {
             app.UseExceptionHandler("/Error");
         }
 
+        app.UseAuthentication();
+        app.UseAuthorization();
         app.UseStatusCodePagesWithReExecute("/not-found", createScopeForStatusCodePages: true);
         app.UseHsts();
         app.UseHttpsRedirection();
diff --git a/Server.csproj b/Server.csproj
index 5188548..eb636a3 100644
--- a/Server.csproj
+++ b/Server.csproj
@@ -38,6 +38,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="10.0.9" />
     <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.Server" Version="10.0.8" />
     <PackageReference Include="Magick.NET-Q16-AnyCPU" Version="14.14.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="10.0.8" />
@@ -45,10 +46,12 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="8.19.1" />
     <PackageReference Include="Mime-Detective" Version="25.8.1" />
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="10.0.2" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="10.2.1" />
     <PackageReference Include="System.Drawing.Common" Version="10.0.8" />
+    <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="8.19.1" />
     <PackageReference Include="Tesseract" Version="5.2.0" />
   </ItemGroup>