[refactor] Extract the platform-specific TrustStore instantiations and

net/cert/internal/system_trust_store.cc

+// Copyright 2017 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.
+
+#include "net/cert/internal/system_trust_store.h"
+
+#if defined(USE_NSS_CERTS)
+#include <cert.h>
+#include <pk11pub.h>
+#elif defined(OS_MACOSX) && !defined(OS_IOS)
+#include <Security/Security.h>
+#endif
+
+#include "base/memory/ptr_util.h"
+#include "net/cert/internal/trust_store_collection.h"
+#include "net/cert/internal/trust_store_in_memory.h"
+
+#if defined(USE_NSS_CERTS)
+#include "crypto/nss_util.h"
+#include "net/cert/internal/cert_issuer_source_nss.h"
+#include "net/cert/internal/trust_store_nss.h"
+#include "net/cert/scoped_nss_types.h"
+#elif defined(OS_MACOSX) && !defined(OS_IOS)
+#include "net/cert/internal/trust_store_mac.h"
+#endif
+
+namespace net {
+
+namespace {
+
+// Abstract implementation of SystemTrustStore to be used as a base class.
+// Handles the addition of additional trust anchors.
+class BaseSystemTrustStore : public SystemTrustStore {
+ public:
+  BaseSystemTrustStore() {
+    trust_store_.AddTrustStore(&additional_trust_store_);
+  }
+
+  void AddTrustAnchor(const scoped_refptr<TrustAnchor>& trust_anchor) override {
+    additional_trust_store_.AddTrustAnchor(trust_anchor);
+  }
+
+  TrustStore* GetTrustStore() override { return &trust_store_; }
+
+  CertIssuerSource* GetCertIssuerSource() override { return nullptr; }
+
+  bool IsAdditionalTrustAnchor(
+      const scoped_refptr<TrustAnchor>& trust_anchor) const override {
+    return additional_trust_store_.Contains(trust_anchor.get());
+  }
+
+ protected:
+  TrustStoreCollection trust_store_;
+  TrustStoreInMemory additional_trust_store_;
+};
+
+}  // namespace
+
+#if defined(USE_NSS_CERTS)
+namespace {
+
+class SystemTrustStoreNSS : public BaseSystemTrustStore {
+ public:
+  explicit SystemTrustStoreNSS() : trust_store_nss_(trustSSL) {
+    trust_store_.AddTrustStore(&trust_store_nss_);
+  }
+
+  CertIssuerSource* GetCertIssuerSource() override {
+    return &cert_issuer_source_nss_;
+  }
+
+  bool UsesSystemTrustStore() const override { return true; }
+
+  // IsKnownRoot returns true if the given trust anchor is a standard one (as
+  // opposed to a user-installed root)
+  bool IsKnownRoot(
+      const scoped_refptr<TrustAnchor>& trust_anchor) const override {
+    // TODO(eroman): Based on how the TrustAnchors are created by this
+    // integration, there will always be an associated certificate. However this
+    // contradicts the API for TrustAnchor that states it is optional.
+    DCHECK(trust_anchor->cert());
+
+    // TODO(eroman): The overall approach of IsKnownRoot() is inefficient -- it
+    // requires searching for the trust anchor by DER in NSS, however path
+    // building already had a handle to it.
+    SECItem der_cert;
+    der_cert.data =
+        const_cast<uint8_t*>(trust_anchor->cert()->der_cert().UnsafeData());
+    der_cert.len = trust_anchor->cert()->der_cert().Length();
+    der_cert.type = siDERCertBuffer;
+    ScopedCERTCertificate nss_cert(
+        CERT_FindCertByDERCert(CERT_GetDefaultCertDB(), &der_cert));
+    if (!nss_cert)
+      return false;
+
+    return IsKnownRoot(nss_cert.get());
+  }
+
+ private:
+  // TODO(eroman): This function was copied verbatim from
+  // cert_verify_proc_nss.cc
+  //
+  // IsKnownRoot returns true if the given certificate is one that we believe
+  // is a standard (as opposed to user-installed) root.
+  bool IsKnownRoot(CERTCertificate* root) const {
+    if (!root || !root->slot)
+      return false;
+
+    // This magic name is taken from
+    // http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/security/nss/lib/ckfw/builtins/constants.c&rev=1.13&mark=86,89#79
+    return 0 == strcmp(PK11_GetSlotName(root->slot), "NSS Builtin Objects");
+  }
+
+  TrustStoreNSS trust_store_nss_;
+  CertIssuerSourceNSS cert_issuer_source_nss_;
+};
+
+}  // namespace
+
+std::unique_ptr<SystemTrustStore> CreateSslSystemTrustStore() {
+  return base::MakeUnique<SystemTrustStoreNSS>();
+}
+
+#elif defined(OS_MACOSX) && !defined(OS_IOS)
+
+class SystemTrustStoreMac : public BaseSystemTrustStore {
+ public:
+  explicit SystemTrustStoreMac() : trust_store_mac_(kSecPolicyAppleSSL) {
+    trust_store_.AddTrustStore(&trust_store_mac_);
+  }
+
+  CertIssuerSource* GetCertIssuerSource() override {
+    // TODO(eroman): Should this return something?
+    return nullptr;
+  }
+
+  bool UsesSystemTrustStore() const override { return true; }
+
+  // IsKnownRoot returns true if the given trust anchor is a standard one (as
+  // opposed to a user-installed root)
+  bool IsKnownRoot(
+      const scoped_refptr<TrustAnchor>& trust_anchor) const override {
+    // TODO(eroman): Implement.
+    return false;
+  }
+
+ private:
+  TrustStoreMac trust_store_mac_;
+};
+
+std::unique_ptr<SystemTrustStore> CreateSslSystemTrustStore() {
+  return base::MakeUnique<SystemTrustStoreMac>();
+}
+#else
+
+class DummySystemTrustStore : public BaseSystemTrustStore {
+ public:
+  bool UsesSystemTrustStore() const override { return false; }
+
+  bool IsKnownRoot(
+      const scoped_refptr<TrustAnchor>& trust_anchor) const override {
+    return false;
+  }
+};
+
+std::unique_ptr<SystemTrustStore> CreateSslSystemTrustStore() {
+  return base::MakeUnique<DummySystemTrustStore>();
+}
+#endif
+
+}  // namespace net