setup: add support for transfering or removing authenticators (#354)

- add methods for remove auth via challenge
- add `transfer_start` and `transfer_finish` to account linker

src/commands/setup.rs

@@ -2,7 +2,7 @@ use log::*;
 use phonenumber::PhoneNumber;
 use secrecy::ExposeSecret;
 use steamguard::{
-	accountlinker::{AccountLinkConfirmType, AccountLinkSuccess},
+	accountlinker::{AccountLinkConfirmType, AccountLinkSuccess, RemoveAuthenticatorError},
 	phonelinker::PhoneLinker,
 	steamapi::PhoneClient,
 	token::Tokens,
@@ -43,12 +43,10 @@ where
 
 		info!("Adding authenticator...");
 		let mut linker = AccountLinker::new(transport.clone(), tokens);
-		let link: AccountLinkSuccess;
 		loop {
 			match linker.link() {
-				Ok(a) => {
-					link = a;
-					break;
+				Ok(link) => {
+					return Self::add_new_account(link, manager, account_name, linker);
 				}
 				Err(AccountLinkError::MustProvidePhoneNumber) => {
 					// As of Dec 12, 2023, Steam no longer appears to require a phone number to add an authenticator. Keeping this code here just in case.
@@ -59,6 +57,49 @@ where
 					println!("Check your email and click the link.");
 					tui::pause();
 				}
+				Err(AccountLinkError::AuthenticatorPresent) => {
+					eprintln!("It looks like there's already an authenticator on this account. If you want to link it to steamguard-cli, you'll need to remove it first. If you remove it using your revocation code (R#####), you'll get a 15 day trade ban.");
+					eprintln!("However, you can \"transfer\" the authenticator to steamguard-cli if you have access to the phone number associated with your account. This will cause you to get only a 2 day trade ban.");
+					eprintln!("If you were using SDA or WinAuth, you can import it into steamguard-cli with the `import` command, and have no trade ban.");
+					eprintln!("You can't have the same authenticator on steamguard-cli and the steam mobile app at the same time.");
+
+					eprintln!("\nHere are your options:");
+					eprintln!("[T] Transfer authenticator to steamguard-cli (2 day trade ban)");
+					eprintln!("[R] Revoke authenticator with revocation code (15 day trade ban)");
+					eprintln!("[A] Abort setup");
+					let answer = tui::prompt_char("What would you like to do?", "Tra");
+					match answer {
+						't' => return Self::transfer_new_account(linker, manager),
+						'r' => {
+							loop {
+								let revocation_code =
+									tui::prompt_non_empty("Enter your revocation code (R#####): ");
+								match linker.remove_authenticator(Some(&revocation_code)) {
+									Ok(_) => break,
+									Err(RemoveAuthenticatorError::IncorrectRevocationCode {
+										attempts_remaining,
+									}) => {
+										error!(
+											"Revocation code was incorrect ({} attempts remaining)",
+											attempts_remaining
+										);
+										if attempts_remaining == 0 {
+											error!("No attempts remaining, aborting!");
+											bail!("Failed to remove authenticator: no attempts remaining")
+										}
+									}
+									Err(err) => {
+										error!("Failed to remove authenticator: {}", err);
+									}
+								}
+							}
+						}
+						_ => {
+							info!("Aborting account linking.");
+							return Err(AccountLinkError::AuthenticatorPresent.into());
+						}
+					}
+				}
 				Err(err) => {
 					error!(
 						"Failed to link authenticator. Account has not been linked. {}",
@@ -68,6 +109,20 @@ where
 				}
 			}
 		}
+	}
+}
+
+impl SetupCommand {
+	/// Add a new account to the manifest after linking has started.
+	fn add_new_account<T>(
+		link: AccountLinkSuccess,
+		manager: &mut AccountManager,
+		account_name: String,
+		mut linker: AccountLinker<T>,
+	) -> Result<(), anyhow::Error>
+	where
+		T: Transport + Clone,
+	{
 		let mut server_time = link.server_time();
 		let phone_number_hint = link.phone_number_hint().to_owned();
 		let confirm_type = link.confirm_type();
@@ -83,15 +138,12 @@ where
 				return Err(err);
 			}
 		}
-
 		let account_arc = manager
 			.get_account(&account_name)
 			.expect("account was not present in manifest");
 		let mut account = account_arc.lock().unwrap();
-
 		eprintln!("Authenticator has not yet been linked. Before continuing with finalization, please take the time to write down your revocation code: {}", account.revocation_code.expose_secret());
 		tui::pause();
-
 		debug!("attempting link finalization");
 		let confirm_code = match confirm_type {
 			AccountLinkConfirmType::Email => {
@@ -112,7 +164,6 @@ where
 				bail!("Unknown link confirm type: {}", t);
 			}
 		};
-
 		let mut tries = 0;
 		loop {
 			match linker.finalize(server_time, &mut account, confirm_code.clone()) {
@@ -133,8 +184,7 @@ where
 			}
 		}
 		let revocation_code = account.revocation_code.clone();
-		drop(account); // explicitly drop the lock so we don't hang on the mutex
-
+		drop(account);
 		info!("Verifying authenticator status...");
 		let status =
 			linker.query_status(&manager.get_account(&account_name).unwrap().lock().unwrap())?;
@@ -147,7 +197,6 @@ where
 			manager.save()?;
 			bail!("Authenticator finalization was unsuccessful. You may have entered the wrong confirm code in the previous step. Try again.");
 		}
-
 		info!("Authenticator finalized.");
 		match manager.save() {
 			Ok(_) => {}
@@ -159,12 +208,52 @@ where
 				return Err(err);
 			}
 		}
-
 		eprintln!(
 			"Authenticator has been finalized. Please actually write down your revocation code: {}",
 			revocation_code.expose_secret()
 		);
+		Ok(())
+	}
 
+	/// Transfer an existing authenticator to steamguard-cli.
+	fn transfer_new_account<T>(
+		mut linker: AccountLinker<T>,
+		manager: &mut AccountManager,
+	) -> anyhow::Result<()>
+	where
+		T: Transport + Clone,
+	{
+		info!("Transferring authenticator to steamguard-cli");
+		linker.transfer_start()?;
+
+		let account: SteamGuardAccount;
+		loop {
+			let sms_code = tui::prompt_non_empty("Enter SMS code: ");
+			match linker.transfer_finish(sms_code) {
+				Ok(acc) => {
+					account = acc;
+					break;
+				}
+				Err(err) => {
+					error!("Failed to transfer authenticator: {}", err);
+				}
+			}
+		}
+		info!("Transfer successful, adding account to manifest");
+		let revocation_code = account.revocation_code.clone();
+		eprintln!(
+			"Take a moment to write down your revocation code: {}",
+			revocation_code.expose_secret()
+		);
+
+		manager.add_account(account);
+
+		manager.save()?;
+
+		eprintln!(
+			"Make sure you have your revocation code written down: {}",
+			revocation_code.expose_secret()
+		);
 		Ok(())
 	}
 }

steamguard/src/accountlinker.rs

@@ -1,5 +1,7 @@
 use crate::protobufs::service_twofactor::{
 	CTwoFactor_AddAuthenticator_Request, CTwoFactor_FinalizeAddAuthenticator_Request,
+	CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Request,
+	CTwoFactor_RemoveAuthenticatorViaChallengeStart_Request,
 	CTwoFactor_RemoveAuthenticator_Request, CTwoFactor_Status_Request, CTwoFactor_Status_Response,
 };
 use crate::steamapi::twofactor::TwoFactorClient;
@@ -172,6 +174,63 @@ where
 
 		Ok(())
 	}
+
+	/// Begin the process of "transfering" a mobile authenticator from a different device to this device.
+	///
+	/// "Transfering" does not actually literally transfer the secrets from one device to another. Instead, it generates a new set of secrets on this device, and invalidates the old secrets on the other device. Call [`Self::transfer_finish`] to complete the process.
+	pub fn transfer_start(&mut self) -> Result<(), TransferError> {
+		let req = CTwoFactor_RemoveAuthenticatorViaChallengeStart_Request::new();
+		let resp = self
+			.client
+			.remove_authenticator_via_challenge_start(req, self.tokens().access_token())?;
+		if resp.result != EResult::OK {
+			return Err(resp.result.into());
+		}
+		// the success field in the response is always None, so we can't check that
+		// it appears to not be used at all
+		Ok(())
+	}
+
+	/// Completes the process of "transfering" a mobile authenticator from a different device to this device.
+	pub fn transfer_finish(
+		&mut self,
+		sms_code: impl AsRef<str>,
+	) -> Result<SteamGuardAccount, TransferError> {
+		let access_token = self.tokens.access_token();
+		let steam_id = access_token
+			.decode()
+			.context("decoding access token")?
+			.steam_id();
+		let mut req = CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Request::new();
+		req.set_sms_code(sms_code.as_ref().to_owned());
+		req.set_generate_new_token(true);
+		let resp = self
+			.client
+			.remove_authenticator_via_challenge_continue(req, access_token)?;
+		if resp.result != EResult::OK {
+			return Err(resp.result.into());
+		}
+		let resp = resp.into_response_data();
+		let mut resp = resp.replacement_token.clone().unwrap();
+		let account = SteamGuardAccount {
+			account_name: resp.take_account_name(),
+			steam_id,
+			serial_number: resp.serial_number().to_string(),
+			revocation_code: resp.take_revocation_code().into(),
+			uri: resp.take_uri().into(),
+			shared_secret: TwoFactorSecret::from_bytes(resp.take_shared_secret()),
+			token_gid: resp.take_token_gid(),
+			identity_secret: base64::engine::general_purpose::STANDARD
+				.encode(resp.take_identity_secret())
+				.into(),
+			device_id: self.device_id.clone(),
+			secret_1: base64::engine::general_purpose::STANDARD
+				.encode(resp.take_secret_1())
+				.into(),
+			tokens: Some(self.tokens.clone()),
+		};
+		Ok(account)
+	}
 }
 
 #[derive(Debug)]
@@ -303,3 +362,24 @@ impl From<EResult> for RemoveAuthenticatorError {
 		Self::UnknownEResult(e)
 	}
 }
+
+#[derive(Error, Debug)]
+pub enum TransferError {
+	#[error("Provided SMS code was incorrect.")]
+	BadSmsCode,
+	#[error("Failed to send request to Steam: {0:?}")]
+	Transport(#[from] crate::transport::TransportError),
+	#[error("Steam returned an unexpected error code: {0:?}")]
+	UnknownEResult(EResult),
+	#[error(transparent)]
+	Unknown(#[from] anyhow::Error),
+}
+
+impl From<EResult> for TransferError {
+	fn from(result: EResult) -> Self {
+		match result {
+			EResult::SMSCodeFailed => TransferError::BadSmsCode,
+			r => TransferError::UnknownEResult(r),
+		}
+	}
+}

steamguard/src/steamapi/twofactor.rs

@@ -69,6 +69,45 @@ where
 		Ok(resp)
 	}
 
+	pub fn remove_authenticator_via_challenge_start(
+		&self,
+		req: CTwoFactor_RemoveAuthenticatorViaChallengeStart_Request,
+		access_token: &Jwt,
+	) -> Result<ApiResponse<CTwoFactor_RemoveAuthenticatorViaChallengeStart_Response>, TransportError>
+	{
+		let req = ApiRequest::new(SERVICE_NAME, "RemoveAuthenticatorViaChallengeStart", 1, req)
+			.with_access_token(access_token);
+		let resp = self
+			.transport
+			.send_request::<CTwoFactor_RemoveAuthenticatorViaChallengeStart_Request, CTwoFactor_RemoveAuthenticatorViaChallengeStart_Response>(
+				req,
+			)?;
+		Ok(resp)
+	}
+
+	pub fn remove_authenticator_via_challenge_continue(
+		&self,
+		req: CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Request,
+		access_token: &Jwt,
+	) -> Result<
+		ApiResponse<CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Response>,
+		TransportError,
+	> {
+		let req = ApiRequest::new(
+			SERVICE_NAME,
+			"RemoveAuthenticatorViaChallengeContinue",
+			1,
+			req,
+		)
+		.with_access_token(access_token);
+		let resp = self
+			.transport
+			.send_request::<CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Request, CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Response>(
+				req,
+			)?;
+		Ok(resp)
+	}
+
 	pub fn query_status(
 		&self,
 		req: CTwoFactor_Status_Request,
@@ -108,5 +147,13 @@ macro_rules! impl_buildable_req {
 impl_buildable_req!(CTwoFactor_AddAuthenticator_Request, true);
 impl_buildable_req!(CTwoFactor_FinalizeAddAuthenticator_Request, true);
 impl_buildable_req!(CTwoFactor_RemoveAuthenticator_Request, true);
+impl_buildable_req!(
+	CTwoFactor_RemoveAuthenticatorViaChallengeStart_Request,
+	true
+);
+impl_buildable_req!(
+	CTwoFactor_RemoveAuthenticatorViaChallengeContinue_Request,
+	true
+);
 impl_buildable_req!(CTwoFactor_Status_Request, true);
 impl_buildable_req!(CTwoFactor_Time_Request, false);