Add error information to VerifyCertificateChain().

net/cert/internal/cert_errors.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// ----------------------------
+// Overview of error design
+// ----------------------------
+//
+// Certificate path validation may emit a sequence of errors/warnings. These
+// are represented by |CertErrors|.
+//
+// |CertErrors| is basically just a sequence of errors. The order of the errors
+// reflects when they were added.
+//
+// Each |CertError| has three parts:
+//
+//   * A unique identifier for the error/warning
+//       - essentially an error code
+//
+//   * Optional parameters specific to this error type
+//       - May identify relevant DER or OIDs in the certificate
+//
+//   * Optional context that describes where the error happened
+//       - Which certificate or trust anchor were we processing when the error
+//         was encountered?
+//
+
+#ifndef NET_CERT_INTERNAL_CERT_ERRORS_H_
+#define NET_CERT_INTERNAL_CERT_ERRORS_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "net/base/net_export.h"
+#include "net/der/input.h"
+
+namespace base {
+class Value;
+}
+
+namespace net {
+
+class ParsedCertificate;
+class TrustAnchor;
+
+// Certificate error types are identified by null-terminated C-strings, with
+// unique pointer values.
+//
+// Equality of CertErrorType is done using (pointer) equality and not string
+// comparison.
+//
+// To ensure uniqueness define errors using the macro DEFINE_CERT_ERROR_TYPE().
+using CertErrorType = const char*;
+
+// TODO(crbug.com/634443): Implement this -- add magic to ensure that storage
+//                         of identical strings isn't pool.
+#define DEFINE_CERT_ERROR_TYPE(name, c_str_literal) \
+  CertErrorType name = c_str_literal
+
+// CertErrorParams is a base class for describing parameters for a particular
+// CertErrorType.
+//
+// Parameters may be used to associate extra information with an error. An
+// example use for parameters is to identify the OID for an unconsumed critical
+// extension.
+class NET_EXPORT CertErrorParams {
+ public:
+  CertErrorParams();
+  virtual ~CertErrorParams();
+
+  // Creates a representation of this parameter as a base::Value, which may be
+  // used for pretty printing the error.
+  virtual std::unique_ptr<base::Value> ToValue() const = 0;
+
+  // TODO(crbug.com/634443): Add methods access the underlying structure.
+  // ToValue() alone is not a great way to get at the data.
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CertErrorParams);
+};
+
+// CertError represents a single error during path validation.
+struct NET_EXPORT CertError {
+  CertError();
+  CertError(CertError&& other);
+  ~CertError();
+
+  // The "type" of the error. This describes the error class -- what is
+  // typically done using an integer error code.
+  CertErrorType type = nullptr;
+
+  // This describes any parameter relevant to the error.
+  std::unique_ptr<CertErrorParams> params;
+
+  // TODO(crbug.com/634443): Add context (i.e. associated certificate/trust
+  // anchor).
+};
+
+class NET_EXPORT CertErrors {
+ public:
+  CertErrors();
+  ~CertErrors();
+
+  void Add(CertErrorType type);
+
+  void AddWithParam(CertErrorType type,
+                    std::unique_ptr<CertErrorParams> params);
+
+  void AddWith1DerParam(CertErrorType type, const der::Input& der1);
+  void AddWith2DerParams(CertErrorType type,
+                         const der::Input& der1,
+                         const der::Input& der2);
+
+  const std::vector<CertError>& errors() const { return errors_; }
+
+ private:
+  std::vector<CertError> errors_;
+
+  DISALLOW_COPY_AND_ASSIGN(CertErrors);
+};
+
+// --------------------------
+// Context scopers
+// --------------------------
+
+// TODO(crbug.com/634443): Implement.
+class NET_EXPORT ScopedCertErrorsCertContext {
+ public:
+  ScopedCertErrorsCertContext(CertErrors* parent,
+                              const ParsedCertificate* cert,
+                              size_t i);
+  ~ScopedCertErrorsCertContext();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedCertErrorsCertContext);
+};
+
+// TODO(crbug.com/634443): Implement.
+class NET_EXPORT ScopedCertErrorsTrustAnchorContext {
+ public:
+  ScopedCertErrorsTrustAnchorContext(CertErrors* parent,
+                                     const TrustAnchor* trust_anchor);
+  ~ScopedCertErrorsTrustAnchorContext();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedCertErrorsTrustAnchorContext);
+};
+
+// --------------------------
+// Error parameters
+// --------------------------
+
+class NET_EXPORT CertErrorParamsDer1 : public CertErrorParams {
+ public:
+  explicit CertErrorParamsDer1(const der::Input& der1);
+
+  std::unique_ptr<base::Value> ToValue() const override;
+
+ private:
+  const std::string der1_;
+
+  DISALLOW_COPY_AND_ASSIGN(CertErrorParamsDer1);
+};
+
+class NET_EXPORT CertErrorParamsDer2 : public CertErrorParams {
+ public:
+  CertErrorParamsDer2(const der::Input& der1, const der::Input& der2);
+
+  std::unique_ptr<base::Value> ToValue() const override;
+
+ private:
+  const std::string der1_;
+  const std::string der2_;
+
+  DISALLOW_COPY_AND_ASSIGN(CertErrorParamsDer2);
+};
+
+}  // namespace net
+
+#endif  // NET_CERT_INTERNAL_CERT_ERRORS_H_