Merge pull request 'Add support for domain checks.' (#11) from domain-check into main

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/tricot/pulls/11

2 files changed, 158 insertions, 39 deletions

diff --git a/src/cert_store.rs b/src/cert_store.rs
index 0ced178..edbd0a1 100644
--- a/src/cert_store.rs
+++ b/src/cert_store.rs
@@ -22,12 +22,19 @@ pub struct CertStore {
 	consul: Consul,
 	node_name: String,
 	letsencrypt_email: String,
+
 	certs: RwLock<HashMap<String, Arc<Cert>>>,
 	self_signed_certs: RwLock<HashMap<String, Arc<Cert>>>,
+
 	rx_proxy_config: watch::Receiver<Arc<ProxyConfig>>,
 	tx_need_cert: mpsc::UnboundedSender<String>,
 }
 
+struct ProcessedDomains {
+	static_domains: HashSet<String>,
+	on_demand_domains: Vec<(glob::Pattern, Option<String>)>,
+}
+
 impl CertStore {
 	pub fn new(
 		consul: Consul,
@@ -41,10 +48,10 @@ impl CertStore {
 		let cert_store = Arc::new(Self {
 			consul,
 			node_name,
+			letsencrypt_email,
 			certs: RwLock::new(HashMap::new()),
 			self_signed_certs: RwLock::new(HashMap::new()),
 			rx_proxy_config,
-			letsencrypt_email,
 			tx_need_cert: tx,
 		});
 
@@ -66,46 +73,72 @@ impl CertStore {
 		let mut rx_proxy_config = self.rx_proxy_config.clone();
 
 		let mut t_last_check: HashMap<String, Instant> = HashMap::new();
+		let mut proc_domains: Option<ProcessedDomains> = None;
 
 		loop {
-			let mut domains: HashSet<String> = HashSet::new();
-
-			select! {
+			let domains = select! {
+				// Refresh some internal states, schedule static_domains for renew
 				res = rx_proxy_config.changed() => {
 					if res.is_err() {
 						bail!("rx_proxy_config closed");
 					}
 
+					let mut static_domains: HashSet<String> = HashSet::new();
+					let mut on_demand_domains: Vec<(glob::Pattern, Option<String>)> = vec![];
+
 					let proxy_config: Arc<ProxyConfig> = rx_proxy_config.borrow().clone();
+
 					for ent in proxy_config.entries.iter() {
-						if let HostDescription::Hostname(domain) = &ent.url_prefix.host {
-							if let Some((host, _port)) = domain.split_once(':') {
-								domains.insert(host.to_string());
-							} else {
-								domains.insert(domain.clone());
-							}
+						// Eagerly generate certificates for domains that
+						// are not patterns
+						match &ent.url_prefix.host {
+							HostDescription::Hostname(domain) => {
+								if let Some((host, _port)) = domain.split_once(':') {
+									static_domains.insert(host.to_string());
+								} else {
+									static_domains.insert(domain.clone());
+								}
+							},
+							HostDescription::Pattern(pattern) => {
+								on_demand_domains.push((pattern.clone(), ent.on_demand_tls_ask.clone()));
+							},
 						}
 					}
+
+					// only static_domains are refreshed
+					proc_domains = Some(ProcessedDomains { static_domains: static_domains.clone(), on_demand_domains });
+					self.domain_validation(static_domains, proc_domains.as_ref()).await
 				}
+				// renew static and on-demand domains
 				need_cert = rx_need_cert.recv() => {
 					match need_cert {
 						Some(dom) => {
-							domains.insert(dom);
+							let mut candidates: HashSet<String> = HashSet::new();
+
+							// collect certificates as much as possible
+							candidates.insert(dom);
 							while let Ok(dom2) = rx_need_cert.try_recv() {
-								domains.insert(dom2);
+								candidates.insert(dom2);
 							}
+
+							self.domain_validation(candidates, proc_domains.as_ref()).await
 						}
 						None => bail!("rx_need_cert closed"),
-					};
+					}
 				}
-			}
+			};
 
+			// Now that we have our list of domains to check,
+			// actually do something
 			for dom in domains.iter() {
+				// Exclude from the list domains that were checked less than 60
+				// seconds ago
 				match t_last_check.get(dom) {
 					Some(t) if Instant::now() - *t < Duration::from_secs(60) => continue,
 					_ => t_last_check.insert(dom.to_string(), Instant::now()),
 				};
 
+				// Actual Let's Encrypt calls are done here (in sister function)
 				debug!("Checking cert for domain: {}", dom);
 				if let Err(e) = self.check_cert(dom).await {
 					warn!("({}) Could not get certificate: {}", dom, e);
@@ -114,18 +147,82 @@ impl CertStore {
 		}
 	}
 
-	fn get_cert_for_https(self: &Arc<Self>, domain: &str) -> Result<Arc<Cert>> {
-		// Check if domain is authorized
-		if !self
-			.rx_proxy_config
-			.borrow()
-			.entries
-			.iter()
-			.any(|ent| ent.url_prefix.host.matches(domain))
-		{
-			bail!("Domain {} should not have a TLS certificate.", domain);
+	async fn domain_validation(
+		&self,
+		candidates: HashSet<String>,
+		maybe_proc_domains: Option<&ProcessedDomains>,
+	) -> HashSet<String> {
+		let mut domains: HashSet<String> = HashSet::new();
+
+		// Handle initialization
+		let proc_domains = match maybe_proc_domains {
+			None => {
+				warn!("Proxy config is not yet loaded, refusing all certificate generation");
+				return domains;
+			}
+			Some(proc) => proc,
+		};
+
+		// Filter certificates...
+		'outer: for candidate in candidates.into_iter() {
+			// Disallow obvious wrong domains...
+			if !candidate.contains('.') || candidate.ends_with(".local") {
+				warn!("{} is probably not a publicly accessible domain, skipping (a self-signed certificate will be used)", candidate);
+				continue;
+			}
+
+			// Try to register domain as a static domain
+			if proc_domains.static_domains.contains(&candidate) {
+				trace!("domain {} validated as static domain", candidate);
+				domains.insert(candidate);
+				continue;
+			}
+
+			// It's not a static domain, maybe an on-demand domain?
+			for (pattern, maybe_check_url) in proc_domains.on_demand_domains.iter() {
+				// check glob pattern
+				if pattern.matches(&candidate) {
+					// if no check url is set, accept domain as long as it matches the pattern
+					let check_url = match maybe_check_url {
+						None => {
+							trace!(
+								"domain {} validated on glob pattern {} only",
+								candidate,
+								pattern
+							);
+							domains.insert(candidate);
+							continue 'outer;
+						}
+						Some(url) => url,
+					};
+
+					// if a check url is set, call it
+					// -- avoid DDoSing a backend
+					tokio::time::sleep(Duration::from_secs(2)).await;
+					match self.on_demand_tls_ask(check_url, &candidate).await {
+						Ok(()) => {
+							trace!(
+								"domain {} validated on glob pattern {} and on check url {}",
+								candidate,
+								pattern,
+								check_url
+							);
+							domains.insert(candidate);
+							continue 'outer;
+						}
+						Err(e) => {
+							warn!("domain {} validation refused  on glob pattern {} and on check url {} with error: {}", candidate, pattern, check_url, e);
+						}
+					}
+				}
+			}
 		}
 
+		return domains;
+	}
+
+	/// This function is also in charge of the refresh of the domain names
+	fn get_cert_for_https(self: &Arc<Self>, domain: &str) -> Result<Arc<Cert>> {
 		// Check in local memory if it exists
 		if let Some(cert) = self.certs.read().unwrap().get(domain) {
 			if cert.is_old() {
@@ -186,6 +283,15 @@ impl CertStore {
 		Ok(())
 	}
 
+	/// Check certificate ensure that the certificate is in the memory store
+	/// and that it does not need to be renewed.
+	///
+	/// If it's not in the memory store, it tries to load it from Consul,
+	/// if it's not in Consul, it calls Let's Encrypt.
+	///
+	/// If the certificate is outdated in the memory store, it tries to load
+	/// a more recent version in Consul, if the Consul version is also outdated,
+	/// it tries to renew it
 	pub async fn check_cert(self: &Arc<Self>, domain: &str) -> Result<()> {
 		// First, try locally.
 		{
@@ -226,15 +332,10 @@ impl CertStore {
 		self.renew_cert(domain).await
 	}
 
+	/// This is the place where certificates are generated or renewed
 	pub async fn renew_cert(self: &Arc<Self>, domain: &str) -> Result<()> {
 		info!("({}) Renewing certificate", domain);
 
-		// Basic sanity check (we could add more kinds of checks here)
-		// This is just to help avoid getting rate-limited against ACME server
-		if !domain.contains('.') || domain.ends_with(".local") {
-			bail!("Probably not a publicly accessible domain, skipping (a self-signed certificate will be used)");
-		}
-
 		// ---- Acquire lock ----
 		// the lock is acquired for half an hour,
 		// so that in case of an error we won't retry before
@@ -350,6 +451,19 @@ impl CertStore {
 		Ok(())
 	}
 
+	async fn on_demand_tls_ask(&self, check_url: &str, domain: &str) -> Result<()> {
+		let httpcli = reqwest::Client::new();
+		let chall_url = format!("{}?domain={}", check_url, domain);
+		info!("({}) On-demand TLS check", domain);
+
+		let httpresp = httpcli.get(&chall_url).send().await?;
+		if httpresp.status() != reqwest::StatusCode::OK {
+			bail!("{} is not authorized for on-demand TLS", domain);
+		}
+
+		Ok(())
+	}
+
 	async fn check_domain_accessibility(&self, domain: &str, session: &str) -> Result<()> {
 		// Returns Ok(()) only if domain is a correct domain name that
 		// redirects to this server
diff --git a/src/proxy_config.rs b/src/proxy_config.rs
index 8381de2..7690f8a 100644
--- a/src/proxy_config.rs
+++ b/src/proxy_config.rs
@@ -108,6 +108,10 @@ pub struct ProxyEntry {
 	/// when matching this rule
 	pub redirects: Vec<(UrlPrefix, UrlPrefix, u16)>,
 
+	/// Wether or not the domain must be validated before asking a certificate
+	/// to let's encrypt (only for Glob patterns)
+	pub on_demand_tls_ask: Option<String>,
+
 	/// Number of calls in progress, used to deprioritize slow back-ends
 	pub calls_in_progress: atomic::AtomicI64,
 	/// Time of last call, used for round-robin selection
@@ -142,14 +146,14 @@ impl ProxyEntry {
 
 		let mut add_headers = vec![];
 		let mut redirects = vec![];
+		let mut on_demand_tls_ask: Option<String> = None;
 		for mid in middleware.into_iter() {
+			// LocalLb and GlobalLb are handled in the parent function
 			match mid {
 				ConfigTag::AddHeader(k, v) => add_headers.push((k.to_string(), v.clone())),
 				ConfigTag::AddRedirect(m, r, c) => redirects.push(((*m).clone(), (*r).clone(), *c)),
-				ConfigTag::LocalLb | ConfigTag::GlobalLb => {
-					/* handled in parent fx */
-					()
-				}
+				ConfigTag::OnDemandTlsAsk(url) => on_demand_tls_ask = Some(url.to_string()),
+				ConfigTag::LocalLb | ConfigTag::GlobalLb => (),
 			};
 		}
 
@@ -166,6 +170,7 @@ impl ProxyEntry {
 			flags,
 			add_headers,
 			redirects,
+			on_demand_tls_ask,
 			// internal
 			last_call: atomic::AtomicI64::from(0),
 			calls_in_progress: atomic::AtomicI64::from(0),
@@ -247,6 +252,7 @@ enum MatchTag {
 enum ConfigTag<'a> {
 	AddHeader(&'a str, String),
 	AddRedirect(UrlPrefix, UrlPrefix, u16),
+	OnDemandTlsAsk(&'a str),
 	GlobalLb,
 	LocalLb,
 }
@@ -321,6 +327,9 @@ fn parse_tricot_tags(tag: &str) -> Option<ParsedTag> {
 				p_match, p_replace, http_code,
 			)))
 		}
+		["tricot-on-demand-tls-ask", url, ..] => {
+			Some(ParsedTag::Middleware(ConfigTag::OnDemandTlsAsk(url)))
+		}
 		["tricot-global-lb", ..] => Some(ParsedTag::Middleware(ConfigTag::GlobalLb)),
 		["tricot-local-lb", ..] => Some(ParsedTag::Middleware(ConfigTag::LocalLb)),
 		_ => None,
@@ -369,13 +378,9 @@ fn parse_consul_service(
 	// some legacy processing that would need a refactor later
 	for mid in collected_middleware.iter() {
 		match mid {
-			ConfigTag::AddHeader(_, _) | ConfigTag::AddRedirect(_, _, _) =>
-			/* not handled here */
-			{
-				()
-			}
 			ConfigTag::GlobalLb => flags.global_lb = true,
 			ConfigTag::LocalLb => flags.site_lb = true,
+			_ => (),
 		};
 	}