Return empty bind response on parse throw

This commit is contained in:
Max Goedjen
2026-09-15 22:09:51 -07:00
parent fddffcebd1
commit f0d6abda40
@@ -142,60 +142,64 @@ extension SSHAgentInputParser {
case SSHAgent.ProtocolExtension.OpenSSHExtension.domain:
switch name {
case SSHAgent.ProtocolExtension.OpenSSHExtension.sessionBind(.empty).name:
let hostkeyBlob = try reader.readNextChunkAsSubReader()
let hostKeyType = try hostkeyBlob.readNextChunkAsString()
let hostKeyData = try hostkeyBlob.readNextChunk()
let sessionID = try reader.readNextChunk()
let signatureBlob = try reader.readNextChunkAsSubReader()
_ = try signatureBlob.readNextChunk() // key type again
let signature = try signatureBlob.readNextChunk()
let forwarding = try reader.readNextByteAsBool()
switch hostKeyType {
case "ssh-ed25519":
let hostKey = try CryptoKit.Curve25519.Signing.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(signature, for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
case "ecdsa-sha2-nistp256":
let hostKey = try CryptoKit.P256.Signing.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(try .init(rawRepresentation: signature), for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
case "ecdsa-sha2-nistp384":
let hostKey = try CryptoKit.P384.Signing.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(try .init(rawRepresentation: signature), for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
case "ssh-mldsa-65":
if #available(macOS 26.0, *) {
let hostKey = try CryptoKit.MLDSA65.PublicKey(rawRepresentation: hostKeyData)
do {
let hostkeyBlob = try reader.readNextChunkAsSubReader()
let hostKeyType = try hostkeyBlob.readNextChunkAsString()
let hostKeyData = try hostkeyBlob.readNextChunk()
let sessionID = try reader.readNextChunk()
let signatureBlob = try reader.readNextChunkAsSubReader()
_ = try signatureBlob.readNextChunk() // key type again
let signature = try signatureBlob.readNextChunk()
let forwarding = try reader.readNextByteAsBool()
switch hostKeyType {
case "ssh-ed25519":
let hostKey = try CryptoKit.Curve25519.Signing.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(signature, for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
} else {
throw AgentParsingError.unhandledRequest
}
case "ssh-mldsa-87":
if #available(macOS 26.0, *) {
let hostKey = try CryptoKit.MLDSA65.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(signature, for: sessionID) else {
case "ecdsa-sha2-nistp256":
let hostKey = try CryptoKit.P256.Signing.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(try .init(rawRepresentation: signature), for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
} else {
case "ecdsa-sha2-nistp384":
let hostKey = try CryptoKit.P384.Signing.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(try .init(rawRepresentation: signature), for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
case "ssh-mldsa-65":
if #available(macOS 26.0, *) {
let hostKey = try CryptoKit.MLDSA65.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(signature, for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
} else {
throw AgentParsingError.unhandledRequest
}
case "ssh-mldsa-87":
if #available(macOS 26.0, *) {
let hostKey = try CryptoKit.MLDSA65.PublicKey(rawRepresentation: hostKeyData)
guard hostKey.isValidSignature(signature, for: sessionID) else {
throw AgentParsingError.incorrectSignature
}
} else {
throw AgentParsingError.unhandledRequest
}
case "ssh-rsa":
throw AgentParsingError.unhandledRequest
default:
throw AgentParsingError.unhandledRequest
}
case "ssh-rsa":
throw AgentParsingError.unhandledRequest
default:
throw AgentParsingError.unhandledRequest
let context = SSHAgent.ProtocolExtension.OpenSSHExtension.SessionBindContext(
hostKey: hostKeyData,
sessionID: sessionID,
signature: signature,
forwarding: forwarding
)
return .openSSH(.sessionBind(context))
} catch {
return .openSSH(.sessionBind(.empty))
}
let context = SSHAgent.ProtocolExtension.OpenSSHExtension.SessionBindContext(
hostKey: hostKeyData,
sessionID: sessionID,
signature: signature,
forwarding: forwarding
)
return .openSSH(.sessionBind(context))
default:
return .openSSH(.unknown(String(name)))
}