http: Sort auto-HTTPS redirect routes by host specificity (fixes #7390)

Author: pauloappbr

caddytest/integration/autohttps_test.go

@@ -143,3 +143,26 @@ func TestAutoHTTPRedirectsInsertedBeforeUserDefinedCatchAllWithNoExplicitHTTPSit
 	tester.AssertGetResponse("http://foo.localhost:9080/", 200, "Foo")
 	tester.AssertGetResponse("http://baz.localhost:9080/", 200, "Foo")
 }
+
+func TestAutoHTTPSRedirectSortingExactMatchOverWildcard(t *testing.T) {
+	tester := caddytest.NewTester(t)
+	tester.InitServer(`
+    {
+        skip_install_trust
+        admin localhost:2999
+        http_port     9080
+        https_port    9443
+        local_certs
+    }
+    *.localhost:10443 {
+        respond "Wildcard"
+    }
+    dev.localhost {
+        respond "Exact"
+    }
+  `, "caddyfile")
+
+	tester.AssertRedirect("http://dev.localhost:9080/", "https://dev.localhost/", http.StatusPermanentRedirect)
+
+	tester.AssertRedirect("http://foo.localhost:9080/", "https://foo.localhost:10443/", http.StatusPermanentRedirect)
+}

modules/caddyhttp/autohttps.go

@@ -424,6 +424,40 @@ redirServersLoop:
 		// we'll create a new server for all the listener addresses
 		// that are unused and serve the remaining redirects from it
 
+		// Sort redirect routes by host specificity to ensure exact matches
+		// take precedence over wildcards, preventing ambiguous routing.
+		slices.SortFunc(routes, func(a, b Route) int {
+			hostA := getFirstHostFromRoute(a)
+			hostB := getFirstHostFromRoute(b)
+
+			// Catch-all routes (empty host) have the lowest priority
+			if hostA == "" && hostB != "" {
+				return 1
+			}
+			if hostB == "" && hostA != "" {
+				return -1
+			}
+
+			hasWildcardA := strings.Contains(hostA, "*")
+			hasWildcardB := strings.Contains(hostB, "*")
+
+			// Exact domains take precedence over wildcards
+			if !hasWildcardA && hasWildcardB {
+				return -1
+			}
+			if hasWildcardA && !hasWildcardB {
+				return 1
+			}
+
+			// If both are exact or both are wildcards, the longer one is more specific
+			if len(hostA) != len(hostB) {
+				return len(hostB) - len(hostA)
+			}
+
+			// Tie-breaker: alphabetical order to ensure determinism
+			return strings.Compare(hostA, hostB)
+		})
+
 		// Use the sorted srvNames to consistently find the target server
 		for _, srvName := range srvNames {
 			srv := app.Servers[srvName]
@@ -793,3 +827,26 @@ func isTailscaleDomain(name string) bool {
 }
 
 type acmeCapable interface{ GetACMEIssuer() *caddytls.ACMEIssuer }
+
+// getFirstHostFromRoute traverses a route's matchers to find the Host rule.
+// Since we are dealing with internally generated redirect routes, the host
+// is typically the first string within the MatchHost.
+func getFirstHostFromRoute(r Route) string {
+	for _, matcherSet := range r.MatcherSets {
+		for _, m := range matcherSet {
+			// Check if the matcher is of type MatchHost (value or pointer)
+			switch hm := m.(type) {
+			case MatchHost:
+				if len(hm) > 0 {
+					return hm[0]
+				}
+			case *MatchHost:
+				if len(*hm) > 0 {
+					return (*hm)[0]
+				}
+			}
+		}
+	}
+	// Return an empty string if it's a catch-all route (no specific host)
+	return ""
+}