From a7af7c486e5240da974e02b7dfee9d265aaa654a Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Tue, 14 Mar 2023 10:29:27 -0600
Subject: caddytls: Allow on-demand w/o ask for internal-only

---
 modules/caddytls/automation.go | 76 +++++++++++++++++++++++-------------------
 1 file changed, 42 insertions(+), 34 deletions(-)

(limited to 'modules')

diff --git a/modules/caddytls/automation.go b/modules/caddytls/automation.go
index 526aef5..fffc0a3 100644
--- a/modules/caddytls/automation.go
+++ b/modules/caddytls/automation.go
@@ -165,40 +165,6 @@ func (ap *AutomationPolicy) Provision(tlsApp *TLS) error {
 		ap.storage = cmStorage
 	}
 
-	// on-demand TLS
-	var ond *certmagic.OnDemandConfig
-	if ap.OnDemand {
-		// ask endpoint is now required after a number of negligence cases causing abuse
-		if tlsApp.Automation == nil || tlsApp.Automation.OnDemand == nil || tlsApp.Automation.OnDemand.Ask == "" {
-			return fmt.Errorf("on-demand TLS cannot be enabled without an 'ask' endpoint to prevent abuse; please refer to documentation for details")
-		}
-		ond = &certmagic.OnDemandConfig{
-			DecisionFunc: func(name string) error {
-				if err := onDemandAskRequest(tlsApp.logger, tlsApp.Automation.OnDemand.Ask, name); err != nil {
-					// distinguish true errors from denials, because it's important to elevate actual errors
-					if errors.Is(err, errAskDenied) {
-						tlsApp.logger.Debug("certificate issuance denied",
-							zap.String("ask_endpoint", tlsApp.Automation.OnDemand.Ask),
-							zap.String("domain", name),
-							zap.Error(err))
-					} else {
-						tlsApp.logger.Error("request to 'ask' endpoint failed",
-							zap.String("ask_endpoint", tlsApp.Automation.OnDemand.Ask),
-							zap.String("domain", name),
-							zap.Error(err))
-					}
-					return err
-				}
-				// check the rate limiter last because
-				// doing so makes a reservation
-				if !onDemandRateLimiter.Allow() {
-					return fmt.Errorf("on-demand rate limit exceeded")
-				}
-				return nil
-			},
-		}
-	}
-
 	// we don't store loaded modules directly in the certmagic config since
 	// policy provisioning may happen more than once (during auto-HTTPS) and
 	// loading a module clears its config bytes; thus, load the module and
@@ -255,6 +221,40 @@ func (ap *AutomationPolicy) Provision(tlsApp *TLS) error {
 		storage = tlsApp.ctx.Storage()
 	}
 
+	// on-demand TLS
+	var ond *certmagic.OnDemandConfig
+	if ap.OnDemand {
+		// ask endpoint is now required after a number of negligence cases causing abuse
+		if !ap.onlyInternalIssuer() && (tlsApp.Automation == nil || tlsApp.Automation.OnDemand == nil || tlsApp.Automation.OnDemand.Ask == "") {
+			return fmt.Errorf("on-demand TLS cannot be enabled without an 'ask' endpoint to prevent abuse; please refer to documentation for details")
+		}
+		ond = &certmagic.OnDemandConfig{
+			DecisionFunc: func(name string) error {
+				if err := onDemandAskRequest(tlsApp.logger, tlsApp.Automation.OnDemand.Ask, name); err != nil {
+					// distinguish true errors from denials, because it's important to elevate actual errors
+					if errors.Is(err, errAskDenied) {
+						tlsApp.logger.Debug("certificate issuance denied",
+							zap.String("ask_endpoint", tlsApp.Automation.OnDemand.Ask),
+							zap.String("domain", name),
+							zap.Error(err))
+					} else {
+						tlsApp.logger.Error("request to 'ask' endpoint failed",
+							zap.String("ask_endpoint", tlsApp.Automation.OnDemand.Ask),
+							zap.String("domain", name),
+							zap.Error(err))
+					}
+					return err
+				}
+				// check the rate limiter last because
+				// doing so makes a reservation
+				if !onDemandRateLimiter.Allow() {
+					return fmt.Errorf("on-demand rate limit exceeded")
+				}
+				return nil
+			},
+		}
+	}
+
 	template := certmagic.Config{
 		MustStaple:         ap.MustStaple,
 		RenewalWindowRatio: ap.RenewalWindowRatio,
@@ -286,6 +286,14 @@ func (ap *AutomationPolicy) Provision(tlsApp *TLS) error {
 	return nil
 }
 
+func (ap *AutomationPolicy) onlyInternalIssuer() bool {
+	if len(ap.Issuers) != 1 {
+		return false
+	}
+	_, ok := ap.Issuers[0].(*InternalIssuer)
+	return ok
+}
+
 // DefaultIssuers returns empty Issuers (not provisioned) to be used as defaults.
 // This function is experimental and has no compatibility promises.
 func DefaultIssuers() []certmagic.Issuer {
-- 
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