mirror of https://github.com/oxen-io/session-ios
Implement file server proxying
Niels Andriesse
5 years ago
parent
8ba452fb56
commit
51fb4ed21d
@ -1 +1 @@
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Subproject commit d7ebdadef0ed419082789e6a1f65a75ff791996e
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Subproject commit 9837a2fa9828fcd261233cff21dc688dc308c6b8
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@ -0,0 +1,106 @@
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import PromiseKit
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internal class LokiFileServerProxy : LokiHTTPClient {
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private let server: String
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private let keyPair = Curve25519.generateKeyPair()
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private static let fileServerPublicKey: Data = {
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let base64EncodedPublicKey = "BWJQnVm97sQE3Q1InB4Vuo+U/T1hmwHBv0ipkiv8tzEc"
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let publicKeyWithPrefix = Data(base64Encoded: base64EncodedPublicKey)!
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let hexEncodedPublicKeyWithPrefix = publicKeyWithPrefix.toHexString()
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let hexEncodedPublicKey = hexEncodedPublicKeyWithPrefix.removing05PrefixIfNeeded()
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return Data(hex: hexEncodedPublicKey)
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}()
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// MARK: Error
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internal enum Error : LocalizedError {
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case symmetricKeyGenerationFailed
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case endpointParsingFailed
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case proxyResponseParsingFailed
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case fileServerHTTPError(code: Int, message: Any?)
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internal var errorDescription: String? {
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switch self {
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case .symmetricKeyGenerationFailed: return "Couldn't generate symmetric key."
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case .endpointParsingFailed: return "Couldn't parse endpoint."
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case .proxyResponseParsingFailed: return "Couldn't parse proxy response."
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case .fileServerHTTPError(let httpStatusCode, let message): return "File server returned error \(httpStatusCode) with description: \(message ?? "no description provided.")."
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}
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}
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}
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// MARK: Initialization
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internal init(for server: String) {
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self.server = server
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super.init()
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}
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// MARK: Proxying
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override internal func perform(_ request: TSRequest, withCompletionQueue queue: DispatchQueue = DispatchQueue.main) -> LokiAPI.RawResponsePromise {
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let uncheckedSymmetricKey = try? Curve25519.generateSharedSecret(fromPublicKey: LokiFileServerProxy.fileServerPublicKey, privateKey: keyPair.privateKey)
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guard let symmetricKey = uncheckedSymmetricKey else { return Promise(error: Error.symmetricKeyGenerationFailed) }
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let headers = getCanonicalHeaders(for: request)
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return LokiAPI.getRandomSnode().then { [server = self.server, keyPair = self.keyPair, httpSession = self.httpSession] proxy -> Promise<Any> in
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let url = "\(proxy.address):\(proxy.port)/proxy"
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print("[Loki] Proxying request to \(server) through \(proxy).")
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guard let urlAsString = request.url?.absoluteString, let serverURLEndIndex = urlAsString.range(of: server)?.upperBound,
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serverURLEndIndex < urlAsString.endIndex else { throw Error.endpointParsingFailed }
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let endpointStartIndex = urlAsString.index(after: serverURLEndIndex)
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let endpoint = String(urlAsString[endpointStartIndex..<urlAsString.endIndex])
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let parametersAsData = try JSONSerialization.data(withJSONObject: request.parameters, options: [])
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let proxyRequestParameters: JSON = [
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"body" : String(bytes: parametersAsData, encoding: .utf8),
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"endpoint": endpoint,
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"method" : request.httpMethod,
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"headers" : headers
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]
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let proxyRequestParametersAsData = try JSONSerialization.data(withJSONObject: proxyRequestParameters, options: [])
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let ivAndCipherText = try DiffieHellman.encrypt(proxyRequestParametersAsData, using: symmetricKey)
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let proxyRequestHeaders = [
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"X-Loki-File-Server-Target" : "/loki/v1/secure_rpc",
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"X-Loki-File-Server-Verb" : "POST",
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"X-Loki-File-Server-Headers" : "{ X-Loki-File-Server-Ephemeral-Key : \(keyPair.publicKey.base64EncodedString()) }",
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"Connection" : "close"
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]
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let (promise, resolver) = LokiAPI.RawResponsePromise.pending()
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let proxyRequest = AFHTTPRequestSerializer().request(withMethod: "POST", urlString: url, parameters: nil, error: nil)
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proxyRequest.allHTTPHeaderFields = proxyRequestHeaders
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proxyRequest.httpBody = try JSONSerialization.data(withJSONObject: [ "cipherText64" : ivAndCipherText.base64EncodedString() ], options: [])
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proxyRequest.timeoutInterval = request.timeoutInterval
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var task: URLSessionDataTask!
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task = httpSession.dataTask(with: proxyRequest as URLRequest) { response, result, error in
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if let error = error {
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let nmError = NetworkManagerError.taskError(task: task, underlyingError: error)
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let nsError: NSError = nmError as NSError
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nsError.isRetryable = false
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resolver.reject(nsError)
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} else {
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resolver.fulfill(result)
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}
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}
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task.resume()
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return promise
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}.map { rawResponse in
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guard let data = rawResponse as? Data, !data.isEmpty, let cipherText = Data(base64Encoded: data) else {
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print("[Loki] Received a non-string encoded response.")
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return rawResponse
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}
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let response = try DiffieHellman.decrypt(cipherText, using: symmetricKey)
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let uncheckedJSON = try? JSONSerialization.jsonObject(with: response, options: .allowFragments) as? JSON
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guard let json = uncheckedJSON, let httpStatusCode = json["status"] as? Int else { throw HTTPError.networkError(code: -1, response: nil, underlyingError: Error.proxyResponseParsingFailed) }
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let isSuccess = (200..<300).contains(httpStatusCode)
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var body: Any? = nil
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if let bodyAsString = json["body"] as? String {
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body = bodyAsString
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if let bodyAsJSON = try? JSONSerialization.jsonObject(with: bodyAsString.data(using: .utf8)!, options: .allowFragments) as? [String: Any] {
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body = bodyAsJSON
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}
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}
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guard isSuccess else { throw HTTPError.networkError(code: httpStatusCode, response: body, underlyingError: Error.fileServerHTTPError(code: httpStatusCode, message: body)) }
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return body
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}.recover { error -> Promise<Any> in
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print("[Loki] Proxy request failed with error: \(error.localizedDescription).")
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throw HTTPError.from(error: error) ?? error
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}
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}
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}
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