refactor: improve sasl config

config.sample.toml

@@ -180,22 +180,19 @@ imap.server = "example.com"
 
 # SASL PLAIN
 # https://datatracker.ietf.org/doc/html/rfc4616
-imap.sasl.plain.authcid = "user@example.com"
-imap.sasl.plain.passwd.raw = "***"
-#imap.sasl.plain.passwd.command = "pass show example"
-#imap.sasl.plain.passwd.command = ["mimosa", "password", "read", "example"]
+imap.sasl.plain.username = "user@example.com"
+imap.sasl.plain.password.raw = "***"
+#imap.sasl.plain.password.command = "pass show example"
 
 # SASL LOGIN
 # https://datatracker.ietf.org/doc/html/draft-murchison-sasl-login-00
 #imap.sasl.login.username = "user@example.com"
 #imap.sasl.login.password.raw = "***"
 
-# SASL OAUTHBEARER (host/port echoed in the GS2 header; usually mirror the
-# server you actually connect to).
+# SASL OAUTHBEARER (host/port for the GS2 header are derived from the
+# IMAP server URL at connect time).
 # https://datatracker.ietf.org/doc/html/rfc7628
 #imap.sasl.oauthbearer.username = "user@example.com"
-#imap.sasl.oauthbearer.host = "imap.example.com"
-#imap.sasl.oauthbearer.port = 993
 #imap.sasl.oauthbearer.token.raw = "***"
 #imap.sasl.oauthbearer.token.command = ["ortie", "token", "read", "example"]
 
@@ -312,19 +309,17 @@ smtp.server = "example.com"
 #smtp.sasl.anonymous.message = "himalaya"
 
 # SASL PLAIN
-smtp.sasl.plain.authcid = "user@example.com"
-smtp.sasl.plain.passwd.raw = "***"
-#smtp.sasl.plain.passwd.command = "pass show example"
-#smtp.sasl.plain.passwd.command = ["mimosa", "password", "read", "example"]
+smtp.sasl.plain.username = "user@example.com"
+smtp.sasl.plain.password.raw = "***"
+#smtp.sasl.plain.password.command = "pass show example"
 
 # SASL LOGIN
 #smtp.sasl.login.username = "user@example.com"
 #smtp.sasl.login.password.raw = "***"
 
-# SASL OAUTHBEARER
+# SASL OAUTHBEARER (host/port for the GS2 header are derived from the
+# SMTP server URL at connect time).
 #smtp.sasl.oauthbearer.username = "user@example.com"
-#smtp.sasl.oauthbearer.host = "smtp.example.com"
-#smtp.sasl.oauthbearer.port = 465
 #smtp.sasl.oauthbearer.token.raw = "***"
 
 # SASL XOAUTH2

src/account/check.rs

@@ -120,9 +120,17 @@ fn check_imap(
 
     let result = (|| -> Result<()> {
         let tls = imap_config.tls.clone().into_tls(imap_config.alpn.clone());
-        let sasl: Option<Sasl> = imap_config.sasl.clone().map(Sasl::try_from).transpose()?;
         let auto_id = resolve_auto_id_params(&imap_config.id)?;
         let server = crate::imap::client::parse_imap_server(&imap_config.server)?;
+        let sasl: Option<Sasl> = imap_config
+            .sasl
+            .clone()
+            .and_then(|cfg| {
+                let host = server.host_str()?;
+                let port = server.port_or_known_default()?;
+                Some(cfg.try_into_sasl(host, port))
+            })
+            .transpose()?;
         let _ = ImapClientStd::connect(&server, &tls, imap_config.starttls, sasl, auto_id)?;
         Ok(())
     })();
@@ -184,9 +192,17 @@ fn check_smtp(
 
     let result = (|| -> Result<()> {
         let tls = smtp_config.tls.clone().into_tls(smtp_config.alpn.clone());
-        let sasl: Option<Sasl> = smtp_config.sasl.clone().map(Sasl::try_from).transpose()?;
         let domain: EhloDomain<'static> = Ipv4Addr::new(127, 0, 0, 1).into();
         let server = crate::smtp::client::parse_smtp_server(&smtp_config.server)?;
+        let sasl: Option<Sasl> = smtp_config
+            .sasl
+            .clone()
+            .and_then(|cfg| {
+                let host = server.host_str()?;
+                let port = server.port_or_known_default()?;
+                Some(cfg.try_into_sasl(host, port))
+            })
+            .transpose()?;
         let _client = SmtpClientStd::connect(&server, &tls, smtp_config.starttls, domain, sasl)?;
         Ok(())
     })();

src/config.rs

@@ -518,14 +518,17 @@ pub struct SaslLoginConfig {
 pub struct SaslPlainConfig {
     pub authzid: Option<String>,
     #[serde(deserialize_with = "shell_expanded_string")]
+    #[serde(alias = "username")]
     pub authcid: String,
+    #[serde(alias = "password")]
     pub passwd: Secret,
 }
 
 /// SASL OAUTHBEARER configuration <sup>[rfc7628]</sup>.
 ///
-/// `host` and `port` are echoed verbatim in the GS2 header and should
-/// match the server the connection is actually opened against.
+/// The `host` and `port` echoed in the GS2 header are derived from
+/// the live IMAP/SMTP server URL at connect time, so they aren't part
+/// of the user-facing config.
 ///
 /// [rfc7628]: https://www.iana.org/go/rfc7628
 #[derive(Clone, Debug, Deserialize, Serialize)]
@@ -533,8 +536,6 @@ pub struct SaslPlainConfig {
 pub struct SaslOauthbearerConfig {
     #[serde(deserialize_with = "shell_expanded_string")]
     pub username: String,
-    pub host: String,
-    pub port: u16,
     pub token: Secret,
 }
 
@@ -559,11 +560,13 @@ pub struct SaslScramSha256Config {
     pub password: Secret,
 }
 
-impl TryFrom<SaslConfig> for Sasl {
-    type Error = anyhow::Error;
-
-    fn try_from(config: SaslConfig) -> Result<Self> {
-        Ok(match config {
+impl SaslConfig {
+    /// Resolves the SASL config into a runtime [`Sasl`]. `host` and
+    /// `port` come from the live server URL; they are only used by
+    /// OAUTHBEARER (echoed in the GS2 header) and ignored by every
+    /// other mechanism.
+    pub fn try_into_sasl(self, host: impl ToString, port: u16) -> Result<Sasl> {
+        Ok(match self {
             SaslConfig::Anonymous(c) => Sasl::Anonymous(SaslAnonymous { message: c.message }),
             SaslConfig::Login(c) => Sasl::Login(SaslLogin {
                 username: c.username,
@@ -576,8 +579,8 @@ impl TryFrom<SaslConfig> for Sasl {
             }),
             SaslConfig::Oauthbearer(c) => Sasl::Oauthbearer(SaslOauthbearer {
                 username: c.username,
-                host: c.host,
-                port: c.port,
+                host: host.to_string(),
+                port,
                 token: c.token.get()?,
             }),
             SaslConfig::Xoauth2(c) => Sasl::Xoauth2(SaslXoauth2 {

src/imap/client.rs

@@ -49,9 +49,16 @@ impl ImapClient {
     /// [`Inner::capability`] explicitly.
     pub fn new(config: ImapConfig) -> Result<Self> {
         let tls = config.tls.into_tls(config.alpn);
-        let sasl: Option<Sasl> = config.sasl.map(Sasl::try_from).transpose()?;
         let auto_id = resolve_auto_id_params(&config.id)?;
         let server = parse_imap_server(&config.server)?;
+        let sasl: Option<Sasl> = config
+            .sasl
+            .and_then(|cfg| {
+                let host = server.host_str()?;
+                let port = server.port_or_known_default()?;
+                Some(cfg.try_into_sasl(host, port))
+            })
+            .transpose()?;
         let (inner, _capability) = Inner::connect(&server, &tls, config.starttls, sasl, auto_id)?;
         Ok(Self { inner })
     }

src/shared/client.rs

@@ -78,9 +78,16 @@ impl EmailClient {
                 use crate::imap::id::resolve_auto_id_params;
 
                 let tls = imap_config.tls.into_tls(imap_config.alpn);
-                let sasl: Option<Sasl> = imap_config.sasl.map(Sasl::try_from).transpose()?;
                 let auto_id = resolve_auto_id_params(&imap_config.id)?;
                 let server = crate::imap::client::parse_imap_server(&imap_config.server)?;
+                let sasl: Option<Sasl> = imap_config
+                    .sasl
+                    .and_then(|cfg| {
+                        let host = server.host_str()?;
+                        let port = server.port_or_known_default()?;
+                        Some(cfg.try_into_sasl(host, port))
+                    })
+                    .transpose()?;
                 let imap =
                     ImapClientStd::connect(&server, &tls, imap_config.starttls, sasl, auto_id)?;
                 inner = inner.with_imap(imap);
@@ -126,9 +133,16 @@ impl EmailClient {
                 use pimalaya_stream::sasl::Sasl;
 
                 let tls = smtp_config.tls.into_tls(smtp_config.alpn);
-                let sasl: Option<Sasl> = smtp_config.sasl.map(Sasl::try_from).transpose()?;
                 let domain: EhloDomain<'static> = Ipv4Addr::new(127, 0, 0, 1).into();
                 let server = crate::smtp::client::parse_smtp_server(&smtp_config.server)?;
+                let sasl: Option<Sasl> = smtp_config
+                    .sasl
+                    .and_then(|cfg| {
+                        let host = server.host_str()?;
+                        let port = server.port_or_known_default()?;
+                        Some(cfg.try_into_sasl(host, port))
+                    })
+                    .transpose()?;
                 inner = inner.with_smtp(SmtpClientStd::connect(
                     &server,
                     &tls,

src/smtp/client.rs

@@ -46,9 +46,16 @@ impl SmtpClient {
     /// SASL).
     pub fn new(config: SmtpConfig) -> Result<Self> {
         let tls = config.tls.into_tls(config.alpn);
-        let sasl: Option<Sasl> = config.sasl.map(Sasl::try_from).transpose()?;
         let domain: EhloDomain<'static> = Ipv4Addr::new(127, 0, 0, 1).into();
         let server = parse_smtp_server(&config.server)?;
+        let sasl: Option<Sasl> = config
+            .sasl
+            .and_then(|cfg| {
+                let host = server.host_str()?;
+                let port = server.port_or_known_default()?;
+                Some(cfg.try_into_sasl(host, port))
+            })
+            .transpose()?;
         let inner = Inner::connect(&server, &tls, config.starttls, domain, sasl)?;
         Ok(Self { inner })
     }