Extend the transport building logic to authenticate via XOAUTH2 if configured.
Previously, the authentication method was determined based on the presence of a password in the config. In order to ensure backwards compatibility with older configurations, continue to do so if auth_method is not set, ensuring configurations that used PLAIN auth before this series keep working as expected. Signed-off-by: Arthur Bied-Charreton <[email protected]> --- proxmox-notify/src/endpoints/smtp.rs | 87 +++++++++++++++++++++++----- 1 file changed, 74 insertions(+), 13 deletions(-) diff --git a/proxmox-notify/src/endpoints/smtp.rs b/proxmox-notify/src/endpoints/smtp.rs index 8a557d88..f9a26b8c 100644 --- a/proxmox-notify/src/endpoints/smtp.rs +++ b/proxmox-notify/src/endpoints/smtp.rs @@ -3,11 +3,12 @@ use std::time::{Duration, SystemTime, UNIX_EPOCH}; use lettre::message::header::{HeaderName, HeaderValue}; use lettre::message::{Mailbox, MultiPart, SinglePart}; +use lettre::transport::smtp::authentication::{Credentials, Mechanism}; use lettre::transport::smtp::client::{Tls, TlsParameters}; use lettre::{Message, SmtpTransport, Transport, message::header::ContentType}; use oauth2::{ClientId, ClientSecret, RefreshToken}; use serde::{Deserialize, Serialize}; -use tracing::info; +use tracing::{debug, info}; use proxmox_schema::api_types::COMMENT_SCHEMA; use proxmox_schema::{Updater, api}; @@ -199,7 +200,7 @@ pub struct SmtpPrivateConfig { pub oauth2_client_secret: Option<String>, } -/// A sendmail notification endpoint. +/// A SMTP notification endpoint. pub struct SmtpEndpoint { pub config: SmtpConfig, pub private_config: SmtpPrivateConfig, @@ -243,22 +244,82 @@ impl SmtpEndpoint { } } + /// Infer the auth method based on the presence of a password field in the private config. + /// + /// This is required for backwards compatibility for configs created before the `auth_method` + /// field was added, i.e., the presence of a password implicitly meant plain authentication + /// was to be used. + fn auth_method(&self) -> Option<SmtpAuthMethod> { + self.config.auth_method.or_else(|| { + if self.private_config.password.is_some() { + Some(SmtpAuthMethod::Plain) + } else { + None + } + }) + } + + /// Build an [`SmtpTransport`] for [`Endpoint::send`]. + /// + /// For OAuth2 auth methods this loads the refresh token from the per-endpoint state file + /// and performs a token exchange at every call. It never persists a rotated token, that + /// responsibility is on [`Self::trigger_state_refresh`], which is called under a notifications + /// config lock. fn build_transport(&self, tls: Tls, port: u16) -> Result<SmtpTransport, Error> { - let mut transport_builder = SmtpTransport::builder_dangerous(&self.config.server) + let transport_builder = SmtpTransport::builder_dangerous(&self.config.server) .tls(tls) .port(port) .timeout(Some(Duration::from_secs(SMTP_TIMEOUT.into()))); - if let Some(username) = self.config.username.as_deref() { - if let Some(password) = self.private_config.password.as_deref() { - transport_builder = transport_builder.credentials((username, password).into()); - } else { - return Err(Error::NotifyFailed( - self.name().into(), - Box::new(Error::Generic( - "username is set but no password was provided".to_owned(), - )), - )); + let transport_builder = match &self.auth_method() { + None => transport_builder, + Some(SmtpAuthMethod::Plain) => match ( + self.config.username.as_deref(), + self.private_config.password.as_deref(), + ) { + (Some(username), Some(password)) => { + transport_builder.credentials((username, password).into()) + } + (Some(_), None) => { + return Err(Error::NotifyFailed( + self.name().into(), + Box::new(Error::Generic( + "username is set but no password was provided".to_owned(), + )), + )); + } + _ => transport_builder, + }, + Some(method) => { + let state = context().load_oauth_state(self.name())?; + + let refresh_token = + state + .oauth2_refresh_token + .clone() + .ok_or(Error::NotifyFailed( + self.name().into(), + Box::new(Error::Generic("no refresh token found".into())), + ))?; + + debug!( + "requesting OAuth2 access token for endpoint '{}'", + self.config.name + ); + + let token_exchange_result = self.get_access_token(&refresh_token, method)?; + + debug!( + "OAuth2 token exchange successful for endpoint '{}'", + self.config.name + ); + + transport_builder + .credentials(Credentials::new( + self.config.from_address.to_owned(), + token_exchange_result.access_token.into_secret(), + )) + .authentication(vec![Mechanism::Xoauth2]) } }; -- 2.47.3
