pki library: Add CertIssuerSourceNSS that retrieves intermediate certs from NSS.

net/cert/internal/cert_issuer_source_nss.cc

Index: net/cert/internal/cert_issuer_source_nss.cc
diff --git a/net/cert/internal/cert_issuer_source_nss.cc b/net/cert/internal/cert_issuer_source_nss.cc
new file mode 100644
index 0000000000000000000000000000000000000000..418efe3ada6a66261239d07d1beb17a0faf7fd7b
--- /dev/null
+++ b/net/cert/internal/cert_issuer_source_nss.cc
@@ -0,0 +1,62 @@
+// 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.
+
+#include "net/cert/internal/cert_issuer_source_nss.h"
+
+#include <cert.h>
+#include <certdb.h>
+
+#include "crypto/nss_util.h"
+#include "net/cert/internal/cert_errors.h"
+#include "net/cert/internal/parsed_certificate.h"
+
+namespace net {
+
+CertIssuerSourceNSS::CertIssuerSourceNSS() = default;
+CertIssuerSourceNSS::~CertIssuerSourceNSS() = default;
+
+void CertIssuerSourceNSS::SyncGetIssuersOf(const ParsedCertificate* cert,
+                                           ParsedCertificateList* issuers) {
+  crypto::EnsureNSSInit();
+
+  SECItem name;
+  // Use the original issuer value instead of the normalized version. NSS does a
+  // less extensive normalization in its Name comparisons, so our normalized
+  // version may not match the unnormalized version.
+  name.len = cert->tbs().issuer_tlv.Length();
+  name.data = const_cast<uint8_t*>(cert->tbs().issuer_tlv.UnsafeData());
+  // |validOnly| in CERT_CreateSubjectCertList controls whether to return only
+  // certs that are valid at |sorttime|. Including expired certs could lead to
+  // more useful error messages in the case where a valid path can't be found,
+  // so request all matches.
+  CERTCertList* found_certs = CERT_CreateSubjectCertList(
+      nullptr /* certList */, CERT_GetDefaultCertDB(), &name,
+      PR_Now() /* sorttime */, PR_FALSE /* validOnly */);
+  if (!found_certs)
+    return;
+
+  for (CERTCertListNode* node = CERT_LIST_HEAD(found_certs);
+       !CERT_LIST_END(node, found_certs); node = CERT_LIST_NEXT(node)) {
+    CertErrors errors;
+    scoped_refptr<ParsedCertificate> issuer_cert = ParsedCertificate::Create(
+        node->cert->derCert.data, node->cert->derCert.len, {}, &errors);
+    if (!issuer_cert) {
+      // TODO(crbug.com/634443): return errors better.
+      LOG(ERROR) << "Error parsing issuer certificate:\n"
+                 << errors.ToDebugString();
+      continue;
+    }
+
+    issuers->push_back(std::move(issuer_cert));
+  }
+  CERT_DestroyCertList(found_certs);
+}
+
+void CertIssuerSourceNSS::AsyncGetIssuersOf(const ParsedCertificate* cert,
+                                            std::unique_ptr<Request>* out_req) {
+  // CertIssuerSourceNSS never returns asynchronous results.
+  out_req->reset();
+}
+
+}  // namespace net