Implement critical security fixes from code review

Dockerfile

@@ -1,7 +1,12 @@
 # Use the official ASP.NET Core runtime image (optimized)
 FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS base
+
+# Define non-root user UID/GID (security best practice)
+ARG APP_UID=1001
+ARG APP_GID=1001
+
 WORKDIR /app
-EXPOSE 5000
+EXPOSE 8080
 
 # Install curl for health checks
 RUN apt-get update && \
@@ -54,31 +59,33 @@ WORKDIR /app
 # Switch to root to create directories and set permissions
 USER root
 
-# Create directories with proper ownership
-RUN mkdir -p /app/wwwroot/uploads/products \
+# Create non-root user and directories with proper ownership
+RUN groupadd -g ${APP_GID} appuser \
+    && useradd -u ${APP_UID} -g ${APP_GID} -m appuser \
+    && mkdir -p /app/wwwroot/uploads/products \
     && mkdir -p /app/data \
     && mkdir -p /app/logs \
-    && chown -R $APP_UID:$APP_UID /app \
+    && chown -R ${APP_UID}:${APP_GID} /app \
     && chmod -R 755 /app/wwwroot/uploads \
     && chmod -R 755 /app/data \
     && chmod -R 755 /app/logs
 
 # Copy published app
-COPY --from=publish --chown=$APP_UID:$APP_UID /app/publish .
+COPY --from=publish --chown=${APP_UID}:${APP_GID} /app/publish .
 
 # Switch back to non-root user
-USER $APP_UID
+USER ${APP_UID}
 
 # Health check
 HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
-    CMD curl -f http://localhost:5000/api/catalog/products || exit 1
+    CMD curl -f http://localhost:8080/health || exit 1
 
 # Optimize runtime
 ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT=0 \
     DOTNET_RUNNING_IN_CONTAINER=true \
     DOTNET_USE_POLLING_FILE_WATCHER=true \
     ASPNETCORE_FORWARDEDHEADERS_ENABLED=true \
-    ASPNETCORE_URLS=http://+:5000 \
+    ASPNETCORE_URLS=http://+:8080 \
     ASPNETCORE_ENVIRONMENT=Production
 
 ENTRYPOINT ["dotnet", "LittleShop.dll"]

LittleShop/Controllers/AuthController.cs

@@ -38,7 +38,7 @@ public class AuthController : ControllerBase
         catch (Exception ex)
         {
             _logger.LogError(ex, "Error during login for user: {Username}", loginDto.Username);
-            return StatusCode(500, new { message = "An error occurred during login", error = ex.Message });
+            return StatusCode(500, new { message = "An error occurred during login" });
         }
     }
 }

LittleShop/Program.cs

@@ -54,6 +54,33 @@ builder.Services.Configure<AspNetCoreRateLimit.IpRateLimitOptions>(options =>
     options.ClientIdHeader = "X-ClientId";
     options.GeneralRules = new List<AspNetCoreRateLimit.RateLimitRule>
     {
+        // Critical: Order creation - very strict limits
+        new AspNetCoreRateLimit.RateLimitRule
+        {
+            Endpoint = "POST:*/api/orders",
+            Period = "1m",
+            Limit = 3
+        },
+        new AspNetCoreRateLimit.RateLimitRule
+        {
+            Endpoint = "POST:*/api/orders",
+            Period = "1h",
+            Limit = 10
+        },
+        // Critical: Payment creation - strict limits
+        new AspNetCoreRateLimit.RateLimitRule
+        {
+            Endpoint = "POST:*/api/orders/*/payments",
+            Period = "1m",
+            Limit = 5
+        },
+        new AspNetCoreRateLimit.RateLimitRule
+        {
+            Endpoint = "POST:*/api/orders/*/payments",
+            Period = "1h",
+            Limit = 20
+        },
+        // Order lookup by identity - moderate limits
         new AspNetCoreRateLimit.RateLimitRule
         {
             Endpoint = "*/api/orders/by-identity/*",
@@ -66,6 +93,21 @@ builder.Services.Configure<AspNetCoreRateLimit.IpRateLimitOptions>(options =>
             Period = "1m",
             Limit = 10
         },
+        // Cancel order endpoint - moderate limits
+        new AspNetCoreRateLimit.RateLimitRule
+        {
+            Endpoint = "POST:*/api/orders/*/cancel",
+            Period = "1m",
+            Limit = 5
+        },
+        // Webhook endpoint - exempt from rate limiting
+        new AspNetCoreRateLimit.RateLimitRule
+        {
+            Endpoint = "POST:*/api/orders/payments/webhook",
+            Period = "1s",
+            Limit = 1000
+        },
+        // General API limits
         new AspNetCoreRateLimit.RateLimitRule
         {
             Endpoint = "*",

LittleShop/Services/ConfigurationValidationService.cs

@@ -29,8 +29,16 @@ public class ConfigurationValidationService
     {
         _logger.LogInformation("🔍 Validating application configuration...");
 
-        // Temporarily disabled for testing SilverPay settings page
-        // ValidateJwtConfiguration();
+        // JWT validation is critical in production, optional in development/testing
+        if (_environment.IsProduction() || !string.IsNullOrEmpty(_configuration["Jwt:Key"]))
+        {
+            ValidateJwtConfiguration();
+        }
+        else if (_environment.IsDevelopment())
+        {
+            _logger.LogWarning("⚠️ JWT validation skipped in development. Configure Jwt:Key for production readiness.");
+        }
+
         ValidateSilverPayConfiguration();
         ValidateProductionSafeguards();
         ValidateEnvironmentConfiguration();