Warns when running TGS as root

build/Dockerfile

@@ -69,6 +69,7 @@ EXPOSE 5000
 
 ENV General__ValidInstancePaths__0 /tgs_instances
 ENV FileLogging__Directory /tgs_logs
+ENV Internal__UsingDocker true
 
 WORKDIR /app
 

src/Tgstation.Server.Host/Components/InstanceManager.cs

@@ -130,6 +130,11 @@ sealed class InstanceManager :
 		/// </summary>
 		readonly SwarmConfiguration swarmConfiguration;
 
+		/// <summary>
+		/// The <see cref="InternalConfiguration"/> for the <see cref="InstanceManager"/>.
+		/// </summary>
+		readonly InternalConfiguration internalConfiguration;
+
 		/// <summary>
 		/// The <see cref="TaskCompletionSource"/> for <see cref="Ready"/>.
 		/// </summary>
@@ -177,6 +182,7 @@ sealed class InstanceManager :
 		/// <param name="platformIdentifier">The value of <see cref="platformIdentifier"/>.</param>
 		/// <param name="generalConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing the value of <see cref="generalConfiguration"/>.</param>
 		/// <param name="swarmConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing the value of <see cref="swarmConfiguration"/>.</param>
+		/// <param name="internalConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing the value of <see cref="internalConfiguration"/>.</param>
 		/// <param name="logger">The value of <see cref="logger"/>.</param>
 		public InstanceManager(
 			IInstanceFactory instanceFactory,
@@ -193,6 +199,7 @@ public InstanceManager(
 			IPlatformIdentifier platformIdentifier,
 			IOptions<GeneralConfiguration> generalConfigurationOptions,
 			IOptions<SwarmConfiguration> swarmConfigurationOptions,
+			IOptions<InternalConfiguration> internalConfigurationOptions,
 			ILogger<InstanceManager> logger)
 		{
 			this.instanceFactory = instanceFactory ?? throw new ArgumentNullException(nameof(instanceFactory));
@@ -209,6 +216,7 @@ public InstanceManager(
 			this.platformIdentifier = platformIdentifier ?? throw new ArgumentNullException(nameof(platformIdentifier));
 			generalConfiguration = generalConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(generalConfigurationOptions));
 			swarmConfiguration = swarmConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(swarmConfigurationOptions));
+			internalConfiguration = internalConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(internalConfigurationOptions));
 			this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
 
 			originalConsoleTitle = console.Title;
@@ -675,6 +683,11 @@ void CheckSystemCompatibility()
 			{
 				if (!systemIdentity.CanCreateSymlinks)
 					throw new InvalidOperationException($"The user running {Constants.CanonicalPackageName} cannot create symlinks! Please try running as an administrative user!");
+
+				if (!platformIdentifier.IsWindows && systemIdentity.IsSuperUser && !internalConfiguration.UsingDocker)
+				{
+					logger.LogWarning("TGS is being run as the root account. This is not recommended.");
+				}
 			}
 
 			// This runs before the real socket is opened, ensures we don't perform reattaches unless we're fairly certain the bind won't fail

src/Tgstation.Server.Host/Configuration/InternalConfiguration.cs

@@ -1,4 +1,6 @@
-namespace Tgstation.Server.Host.Configuration
+using System;
+
+namespace Tgstation.Server.Host.Configuration
 {
 	/// <summary>
 	/// Unstable configuration options used internally by TGS.
@@ -25,6 +27,11 @@ public sealed class InternalConfiguration
 		/// </summary>
 		public bool UsingSystemD { get; set; }
 
+		/// <summary>
+		/// If the server is running inside of a Docker container.
+		/// </summary>
+		public bool UsingDocker => Environment.GetEnvironmentVariable("Internal__UsingDocker")?.Equals("true", StringComparison.OrdinalIgnoreCase) ?? false;
+
 		/// <summary>
 		/// The base path for the app settings configuration files.
 		/// </summary>

src/Tgstation.Server.Host/Security/ISystemIdentity.cs

@@ -24,6 +24,12 @@ public interface ISystemIdentity : IDisposable
 		/// </summary>
 		bool CanCreateSymlinks { get; }
 
+		/// <summary>
+		/// Is this identity a SuperUser for the OS.
+		/// See Administrator on Windows or root on Linux.
+		/// </summary>
+		bool IsSuperUser { get; }
+
 		/// <summary>
 		/// Clone the <see cref="ISystemIdentity"/> creating another copy that must have <see cref="IDisposable.Dispose"/> called on it.
 		/// </summary>

src/Tgstation.Server.Host/Security/PosixSystemIdentity.cs

@@ -2,13 +2,18 @@
 using System.Threading;
 using System.Threading.Tasks;
 
+using Mono.Unix.Native;
+
 namespace Tgstation.Server.Host.Security
 {
 	/// <summary>
 	/// <see cref="ISystemIdentity"/> for POSIX systems.
 	/// </summary>
 	sealed class PosixSystemIdentity : ISystemIdentity
 	{
+		/// <inheritdoc />
+		public bool IsSuperUser => Syscall.getuid() == 0;
+
 		/// <inheritdoc />
 		public string Uid => throw new NotImplementedException();
 

src/Tgstation.Server.Host/Security/WindowsSystemIdentity.cs

@@ -22,7 +22,10 @@ sealed class WindowsSystemIdentity : ISystemIdentity
 		public string Username => userPrincipal?.Name ?? identity!.Name;
 
 		/// <inheritdoc />
-		public bool CanCreateSymlinks => canCreateSymlinks ?? throw new NotSupportedException();
+		public bool CanCreateSymlinks => IsSuperUser;
+
+		/// <inheritdoc />
+		public bool IsSuperUser => isAdmin ?? throw new NotSupportedException();
 
 		/// <summary>
 		/// The <see cref="WindowsIdentity"/> for the <see cref="WindowsSystemIdentity"/>.
@@ -35,9 +38,9 @@ sealed class WindowsSystemIdentity : ISystemIdentity
 		readonly UserPrincipal? userPrincipal;
 
 		/// <summary>
-		/// Backing field for <see cref="CanCreateSymlinks"/>.
+		/// Backing field for <see cref="IsSuperUser"/>.
 		/// </summary>
-		readonly bool? canCreateSymlinks;
+		readonly bool? isAdmin;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="WindowsSystemIdentity"/> class.
@@ -49,7 +52,7 @@ public WindowsSystemIdentity(WindowsIdentity identity)
 			if (identity.IsAnonymous)
 				throw new ArgumentException($"Cannot use anonymous {nameof(WindowsIdentity)} as a {nameof(WindowsSystemIdentity)}!", nameof(identity));
 
-			canCreateSymlinks = new WindowsPrincipal(identity).IsInRole(WindowsBuiltInRole.Administrator);
+			isAdmin = new WindowsPrincipal(identity).IsInRole(WindowsBuiltInRole.Administrator);
 		}
 
 		/// <summary>