ctcloud: CertSpotter-backed CT cloud-resource monitor

Single stateless Go process that consumes CT logs via embedded (patched)
CertSpotter internals, classifies cloud/database/storage DNS identifiers
in-process with a zero-allocation classifier, enriches via round-robin DNS
resolvers with CNAME following, and batch-writes useful findings to PostgreSQL.

- third_party/certspotter: 2-hunk IdentifierSink patch, no stdout/JSON/files
- internal/classify: AWS/Azure/GCP/Firebase/Cloudflare R2/DigitalOcean/Supabase/OCI
- internal/dns: sharded bounded TTL cache, multi-resolver load balancing + failover
- internal/pipeline: bounded queues, dedup, direct-priority load shedding
- internal/store: pgx batch writer, Postgres CT checkpoints (no cert contents)
- internal/probe: optional non-destructive reachability checks (off by default)
- Docker: distroless non-root, read-only rootfs, no app volume, resource limits
- tests enforce 0 allocs/op on the classifier and sink hot path

third_party/certspotter/loglist/validate.go

@@ -0,0 +1,57 @@
+// Copyright (C) 2020 Opsmate, Inc.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License, v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// This software is distributed WITHOUT A WARRANTY OF ANY KIND.
+// See the Mozilla Public License for details.
+
+package loglist
+
+import (
+	"crypto/sha256"
+	"fmt"
+)
+
+func (list *List) Validate() error {
+	for i := range list.Operators {
+		if err := list.Operators[i].Validate(); err != nil {
+			return fmt.Errorf("problem with %dth operator (%s): %w", i, list.Operators[i].Name, err)
+		}
+	}
+	return nil
+}
+
+func (operator *Operator) Validate() error {
+	for i := range operator.Logs {
+		if err := operator.Logs[i].Validate(); err != nil {
+			return fmt.Errorf("problem with %dth non-tiled log (%s): %w", i, operator.Logs[i].LogIDString(), err)
+		}
+	}
+	for i := range operator.TiledLogs {
+		if err := operator.TiledLogs[i].Validate(); err != nil {
+			return fmt.Errorf("problem with %dth tiled log (%s): %w", i, operator.TiledLogs[i].LogIDString(), err)
+		}
+	}
+	return nil
+}
+
+func (log *Log) Validate() error {
+	realLogID := sha256.Sum256(log.Key)
+	if log.LogID != realLogID {
+		return fmt.Errorf("log ID does not match log key")
+	}
+
+	if !log.IsRFC6962() && !log.IsStaticCTAPI() {
+		return fmt.Errorf("URL(s) not provided")
+	} else if log.IsRFC6962() && log.IsStaticCTAPI() {
+		return fmt.Errorf("inconsistent URLs provided")
+	}
+
+	if log.MMD < 0 {
+		return fmt.Errorf("log has a negative MMD")
+	}
+
+	return nil
+}