Messy WIP for agent extensions

Sources/Packages/Sources/SSHProtocolKit/OpenSSHPublicKeyWriter.swift

@@ -19,7 +19,7 @@ public struct OpenSSHPublicKeyWriter: Sendable {
             ("nistp" + String(describing: secret.keyType.size)).lengthAndData +
             secret.publicKey.lengthAndData
         case .mldsa:
-            // https://www.ietf.org/archive/id/draft-sfluhrer-ssh-mldsa-04.txt
+            // https://datatracker.ietf.org/doc/html/draft-sfluhrer-ssh-mldsa-05
             openSSHIdentifier(for: secret.keyType).lengthAndData +
             secret.publicKey.lengthAndData
         case .rsa:

Sources/Packages/Sources/SSHProtocolKit/OpenSSHReader.swift

@@ -39,6 +39,18 @@ public final class OpenSSHReader {
         return convertEndianness ? T(value.bigEndian) : T(value)
     }
 
+    public func readNextByteAsBool() throws(OpenSSHReaderError) -> Bool {
+        let size = MemoryLayout<Bool>.size
+        guard remaining.count >= size else { throw .beyondBounds }
+        let lengthRange = 0..<size
+        let lengthChunk = remaining[lengthRange]
+        remaining.removeSubrange(lengthRange)
+        if remaining.isEmpty {
+            done = true
+        }
+        return unsafe lengthChunk.bytes.unsafeLoad(as: Bool.self)
+    }
+
     public func readNextChunkAsString(convertEndianness: Bool = true) throws(OpenSSHReaderError) -> String {
         try String(decoding: readNextChunk(convertEndianness: convertEndianness), as: UTF8.self)
     }

Sources/Packages/Sources/SSHProtocolKit/OpenSSHSignatureWriter.swift

@@ -17,7 +17,7 @@ public struct OpenSSHSignatureWriter: Sendable {
             // https://datatracker.ietf.org/doc/html/rfc5656#section-3.1
             ecdsaSignature(signature, keyType: secret.keyType)
         case .mldsa:
-            // https://datatracker.ietf.org/doc/html/draft-sfluhrer-ssh-mldsa-00#name-public-key-algorithms
+            // https://datatracker.ietf.org/doc/html/draft-sfluhrer-ssh-mldsa-05
             mldsaSignature(signature, keyType: secret.keyType)
         case .rsa:
             // https://datatracker.ietf.org/doc/html/rfc4253#section-6.6

Sources/Packages/Sources/SSHProtocolKit/SSHAgentProtocol.swift

@@ -19,7 +19,7 @@ extension SSHAgent {
         case lock
         case unlock
         case addSmartcardKeyConstrained
-        case protocolExtension
+        case protocolExtension(ProtocolExtension)
         case unknown(UInt8)
 
         public var protocolID: UInt8 {
@@ -60,18 +60,82 @@ extension SSHAgent {
 
         public struct SignatureRequestContext: Sendable, Codable {
             public let keyBlob: Data
-            public let dataToSign: Data
+            public let dataToSign: SignaturePayload
 
-            public init(keyBlob: Data, dataToSign: Data) {
+            public init(keyBlob: Data, dataToSign: SignaturePayload) {
                 self.keyBlob = keyBlob
                 self.dataToSign = dataToSign
             }
 
             public static var empty: SignatureRequestContext {
-                SignatureRequestContext(keyBlob: Data(), dataToSign: Data())
+                SignatureRequestContext(keyBlob: Data(), dataToSign: SignaturePayload(raw: Data(), decoded: nil))
+            }
+
+            public struct SignaturePayload: Sendable, Codable {
+
+                public let raw: Data
+                public let decoded: DecodedPayload?
+
+                public init(
+                    raw: Data,
+                    decoded: DecodedPayload?
+                ) {
+                    self.raw = raw
+                    self.decoded = decoded
+                }
+
+                public enum DecodedPayload: Sendable, Codable {
+                    case sshConnection(SSHConnectionPayload)
+                    case sshSig(SSHSigPayload)
+
+                    public struct SSHConnectionPayload: Sendable, Codable {
+
+                        public let username: String
+                        public let hasSignature: Bool
+                        public let publicKeyAlgorithm: String
+                        public let publicKey: Data
+                        public let hostKey: Data
+
+                        public init(
+                            username: String,
+                            hasSignature: Bool,
+                            publicKeyAlgorithm: String,
+                            publicKey: Data,
+                            hostKey: Data
+                        ) {
+                            self.username = username
+                            self.hasSignature = hasSignature
+                            self.publicKeyAlgorithm = publicKeyAlgorithm
+                            self.publicKey = publicKey
+                            self.hostKey = hostKey
+                        }
+
+                    }
+
+                    public struct SSHSigPayload: Sendable, Codable {
+
+                        public let namespace: String
+                        public let hashAlgorithm: String
+                        public let hash: Data
+
+                        public init(
+                            namespace: String,
+                            hashAlgorithm: String,
+                            hash: Data,
+                        ) {
+                            self.namespace = namespace
+                            self.hashAlgorithm = hashAlgorithm
+                            self.hash = hash
+                        }
+
+                    }
+                    
+                }
+
             }
         }
 
+
     }
 
     /// The type of the SSH Agent Response, as described in https://datatracker.ietf.org/doc/html/draft-miller-ssh-agent#section-5.1
@@ -88,8 +152,8 @@ extension SSHAgent {
             switch self {
             case .agentFailure: "SSH_AGENT_FAILURE"
             case .agentSuccess: "SSH_AGENT_SUCCESS"
-            case .agentIdentitiesAnswer: "SSH_AGENT_IDENTITIES_ANSWER"
-            case .agentSignResponse: "SSH_AGENT_SIGN_RESPONSE"
+            case .agentIdentitiesAnswer: "SSH2_AGENT_IDENTITIES_ANSWER"
+            case .agentSignResponse: "SSH2_AGENT_SIGN_RESPONSE"
             case .agentExtensionFailure: "SSH_AGENT_EXTENSION_FAILURE"
             case .agentExtensionResponse: "SSH_AGENT_EXTENSION_RESPONSE"
             }

Sources/Packages/Sources/SSHProtocolKit/SSHProtocolExtensions.swift

@@ -0,0 +1,76 @@
+import Foundation
+
+// Extensions, as defined in https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.agent
+
+extension SSHAgent {
+
+    public enum ProtocolExtension: CustomDebugStringConvertible, Codable, Sendable {
+        case openSSH(OpenSSHExtension)
+        case unknown(String)
+
+        public var debugDescription: String {
+            switch self {
+            case let .openSSH(protocolExtension):
+                protocolExtension.debugDescription
+            case .unknown(let string):
+                "Unknown (\(string))"
+            }
+        }
+
+        public static var empty: ProtocolExtension {
+            .unknown("empty")
+        }
+
+        private struct ProtocolExtensionParsingError: Error {}
+
+    }
+
+}
+
+extension SSHAgent.ProtocolExtension {
+
+    public enum OpenSSHExtension: CustomDebugStringConvertible, Codable, Sendable {
+        case sessionBind(SessionBindContext)
+        case unknown(String)
+
+        public static var domain: String {
+            "openssh.com"
+        }
+
+        public var name: String {
+            switch self {
+            case .sessionBind:
+                "session-bind"
+            case .unknown(let name):
+                name
+            }
+        }
+
+        public var debugDescription: String {
+            "\(name)@\(OpenSSHExtension.domain)"
+        }
+    }
+
+}
+
+extension SSHAgent.ProtocolExtension.OpenSSHExtension {
+
+    public struct SessionBindContext: Codable, Sendable {
+
+        public let hostKey: Data
+        public let sessionID: Data
+        public let signature: Data
+        public let forwarding: Bool
+
+        public init(hostKey: Data, sessionID: Data, signature: Data, forwarding: Bool) {
+            self.hostKey = hostKey
+            self.sessionID = sessionID
+            self.signature = signature
+            self.forwarding = forwarding
+        }
+
+        public static let empty = SessionBindContext(hostKey: Data(), sessionID: Data(), signature: Data(), forwarding: false)
+
+    }
+
+}