Validate container ID from XPC requests

Sources/ContainerCommands/Builder/BuilderStart.swift

@@ -200,7 +200,9 @@ extension Application {
                 useRosetta ? nil : "--enable-qemu",
             ].compactMap { $0 }
 
-            try ContainerAPIClient.Utility.validEntityName(Builder.builderContainerId)
+            guard ManagedContainer.nameValid(Builder.builderContainerId) else {
+                throw ContainerizationError(.invalidArgument, message: "container ID \(Builder.builderContainerId) is not a valid container ID")
+            }
 
             let image = try await ClientImage.fetch(
                 reference: builderImage,

Sources/ContainerCommands/Container/ContainerCreate.swift

@@ -70,7 +70,10 @@ extension Application {
             progress.start()
 
             let id = Utility.createContainerID(name: self.managementFlags.name)
-            try Utility.validEntityName(id)
+
+            guard ManagedContainer.nameValid(id) else {
+                throw ContainerizationError(.invalidArgument, message: "container ID \(id) is not a valid container ID")
+            }
 
             let ck = try await Utility.containerConfigFromFlags(
                 id: id,

Sources/ContainerCommands/Container/ContainerRun.swift

@@ -80,7 +80,9 @@ extension Application {
             }
             progress.start()
 
-            try Utility.validEntityName(id)
+            guard ManagedContainer.nameValid(id) else {
+                throw ContainerizationError(.invalidArgument, message: "container ID \(id) is not a valid container ID")
+            }
 
             // Check if container with id already exists.
             let client = ContainerClient()

Sources/ContainerCommands/Machine/MachineCreate.swift

@@ -17,6 +17,7 @@
 import ArgumentParser
 import ContainerAPIClient
 import ContainerPersistence
+import ContainerResource
 import ContainerizationError
 import ContainerizationOCI
 import Foundation
@@ -115,7 +116,9 @@ extension Application {
                 id = "\(imageName)-\(suffix)"
             }
 
-            try Utility.validEntityName(id)
+            guard ManagedContainer.nameValid(id) else {
+                throw ContainerizationError(.invalidArgument, message: "machine ID \(id) is not a valid machine ID")
+            }
 
             let client = MachineClient()
             let (config, resources) = try await MachineClient.machineConfigFromFlags(

Sources/ContainerResource/Container/ManagedContainer.swift

@@ -41,9 +41,12 @@ public struct ManagedContainer: ManagedResource {
     /// not the protocol's 64-hex default.
     public static func generateId() -> String { UUID().uuidString.lowercased() }
 
-    /// Container name rule (mixed case, dots, hyphens, underscores). Duplicated from
-    /// Utility.validEntityName
+    /// Container name rule
     public static func nameValid(_ name: String) -> Bool {
+        // Maximum Linux hostname length is 64, but limit to maximum DNS label length
+        guard name.count <= 63 else {
+            return false
+        }
         let pattern = #"^[a-zA-Z0-9][a-zA-Z0-9_.-]+$"#
         return name.range(of: pattern, options: .regularExpression) != nil
     }

Sources/Services/ContainerAPIService/Client/Utility.swift

@@ -56,14 +56,6 @@ public struct Utility {
         return String(hex.prefix(12))
     }
 
-    public static func validEntityName(_ name: String) throws {
-        let pattern = #"^[a-zA-Z0-9][a-zA-Z0-9_.-]+$"#
-        let regex = try Regex(pattern)
-        if try regex.firstMatch(in: name) == nil {
-            throw ContainerizationError(.invalidArgument, message: "invalid entity name \(name)")
-        }
-    }
-
     public static func validMACAddress(_ macAddress: String) throws {
         let pattern = #"^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$"#
         let regex = try Regex(pattern)

Sources/Services/ContainerAPIService/Server/Containers/ContainersHarness.swift

@@ -54,6 +54,9 @@ public struct ContainersHarness: Sendable {
                 message: "id cannot be empty"
             )
         }
+        guard ManagedContainer.nameValid(id) else {
+            throw ContainerizationError(.invalidArgument, message: "container ID \(id) is not a valid container ID")
+        }
         let stdio = message.stdio()
 
         let data = message.dataNoCopy(key: .dynamicEnv)
@@ -193,6 +196,9 @@ public struct ContainersHarness: Sendable {
             options = try JSONDecoder().decode(ContainerCreateOptions.self, from: odata)
         }
         let config = try JSONDecoder().decode(ContainerConfiguration.self, from: data)
+        guard ManagedContainer.nameValid(config.id) else {
+            throw ContainerizationError(.invalidArgument, message: "container ID \(config.id) is not a valid container ID")
+        }
         let kernel = try JSONDecoder().decode(Kernel.self, from: kdata)
 
         let initImage = message.string(key: .initImage)
@@ -262,6 +268,9 @@ public struct ContainersHarness: Sendable {
         guard let id else {
             throw ContainerizationError(.invalidArgument, message: "id cannot be empty")
         }
+        guard ManagedContainer.nameValid(id) else {
+            throw ContainerizationError(.invalidArgument, message: "container ID \(id) is not a valid container ID")
+        }
         let forceDelete = message.bool(key: .forceDelete)
         try await service.delete(id: id, force: forceDelete)
         return message.reply()
@@ -272,6 +281,9 @@ public struct ContainersHarness: Sendable {
         guard let containerId = message.string(key: .id) else {
             throw ContainerizationError(.invalidArgument, message: "id cannot be empty")
         }
+        guard ManagedContainer.nameValid(containerId) else {
+            throw ContainerizationError(.invalidArgument, message: "container ID \(containerId) is not a valid container ID")
+        }
 
         let size = try await service.containerDiskUsage(id: containerId)
 
@@ -289,6 +301,9 @@ public struct ContainersHarness: Sendable {
                 message: "id cannot be empty"
             )
         }
+        guard ManagedContainer.nameValid(id) else {
+            throw ContainerizationError(.invalidArgument, message: "container ID \(id) is not a valid container ID")
+        }
         let fds = try await service.logs(id: id)
         let reply = message.reply()
         try reply.set(key: .logs, value: fds)
@@ -374,6 +389,9 @@ public struct ContainersHarness: Sendable {
                 message: "id cannot be empty"
             )
         }
+        guard ManagedContainer.nameValid(id) else {
+            throw ContainerizationError(.invalidArgument, message: "container ID \(id) is not a valid container ID")
+        }
         let archive = message.string(key: .archive)
         guard let archive else {
             throw ContainerizationError(

Tests/ContainerResourceTests/ManagedContainerTests.swift

@@ -60,6 +60,13 @@ struct ManagedContainerTests {
         #expect(!ManagedContainer.nameValid("a b"))
     }
 
+    @Test func nameValidRejectsNamesLongerThan63Characters() {
+        let maxValidName = String(repeating: "a", count: 63)
+        let tooLongName = String(repeating: "a", count: 64)
+        #expect(ManagedContainer.nameValid(maxValidName))
+        #expect(!ManagedContainer.nameValid(tooLongName))
+    }
+
     @Test func generateIdIsLowercasedUUID() {
         let id = ManagedContainer.generateId()
         #expect(id == id.lowercased())