Refactoring of Cast-related crypto code

extensions/common/cast/cast_cert_validator_nss.cc

+// Copyright 2014 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 "extensions/common/cast/cast_cert_validator.h"
+
+#include <cert.h>
+#include <cryptohi.h>
+#include <pk11pub.h>
+#include <seccomon.h>
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "crypto/nss_util.h"
+#include "crypto/scoped_nss_types.h"
+#include "extensions/browser/api/cast_channel/cast_auth_ica.h"
+
+namespace extensions {
+namespace core_api {
+namespace cast_crypto {
+
+namespace {
+
+typedef scoped_ptr<
+    CERTCertificate,
+    crypto::NSSDestroyer<CERTCertificate, CERT_DestroyCertificate>>
+    ScopedCERTCertificate;
+
+class CertVerificationContextNSS : public CertVerificationContext {
+ public:
+  explicit CertVerificationContextNSS(CERTCertificate* x509) : x509_(x509) {}

[Ryan Sleevi, 2014/12/15 21:43:00]

NAMING: s/x509/certificate/ (throughout)

[sheretov, 2014/12/16 08:44:21]

Done.

+
+  VerificationResult VerifySignatureOverData(
+      const base::StringPiece& signature,
+      const base::StringPiece& data) const override {
+    // Verify that the |signature| matches |peer_cert|.
+    crypto::ScopedSECKEYPublicKey public_key(
+        CERT_ExtractPublicKey(x509_.get()));
+    if (!public_key.get()) {
+      return VerificationResult(
+          "Unable to extract public key from certificate",
+          VerificationResult::ERROR_CANNOT_EXTRACT_PUBLIC_KEY, PORT_GetError());
+    }
+    SECItem signature_item;
+    signature_item.type = siBuffer;
+    signature_item.data =
+        reinterpret_cast<unsigned char*>(const_cast<char*>(signature.data()));
+    signature_item.len = signature.length();
+    SECStatus verified = VFY_VerifyDataDirect(
+        reinterpret_cast<unsigned char*>(const_cast<char*>(data.data())),
+        data.size(), public_key.get(), &signature_item,
+        SEC_OID_PKCS1_RSA_ENCRYPTION, SEC_OID_SHA1, NULL, NULL);
+
+    if (verified != SECSuccess) {
+      return VerificationResult("Signature verification failed.",
+                                VerificationResult::ERROR_SIGNATURE_INVALID,
+                                PORT_GetError());
+    }
+    VLOG(1) << "Signature verification succeeded";
+    return VerificationResult();
+  }
+
+  std::string getCommonName() const override {
+    char* common_name = CERT_GetCommonName(&x509_->subject);
+    if (!common_name) {
+      LOG(ERROR) << "Certificate does not have common name.";
+      return "";

[Ryan Sleevi, 2014/12/15 21:43:00]

s/""/std::string()

[sheretov, 2014/12/16 08:44:21]

Done.

+    } else {
+      std::string result(common_name);
+      PORT_Free(common_name);
+      return result;
+    }
+  }
+
+ private:
+  ScopedCERTCertificate x509_;
+};
+
+}  // namespace
+
+VerificationResult VerifyCert(const base::StringPiece& device_cert,
+                              const std::vector<std::string>& ica_certs,
+                              CertVerificationContext** out_context) {
+  const std::string kErrorPrefix("Failed to verify credentials: ");
+
+  // If the list of intermediates is empty then use kPublicKeyICA1 as
+  // the trusted CA (legacy case).
+  // Otherwise, use the first intermediate in the list as long as it
+  // is in the allowed list of intermediates.
+  int num_intermediates = ica_certs.size();
+
+  VLOG(1) << "Response has " << num_intermediates << " intermediates";

[Ryan Sleevi, 2014/12/15 21:43:00]

SPAM: This is spammy. Don't log like this. It doesn't tell you anything, and it
adds to bloat.

[sheretov, 2014/12/16 08:44:21]

Done.

+
+  base::StringPiece ica;
+  if (num_intermediates <= 0) {
+    ica = cast_channel::GetDefaultTrustedICAPublicKey();
+  } else {
+    ica = cast_channel::GetTrustedICAPublicKey(ica_certs[0]);
+  }
+  if (ica.empty()) {
+    return VerificationResult(
+        "Disallowed intermediate cert",
+        VerificationResult::ERROR_CERT_NOT_SIGNED_BY_TRUSTED_CA);
+  }
+
+  SECItem trusted_ca_key_der;
+  trusted_ca_key_der.type = SECItemType::siDERCertBuffer;
+  trusted_ca_key_der.data =
+      const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(ica.data()));
+  trusted_ca_key_der.len = ica.size();
+
+  crypto::EnsureNSSInit();
+  SECItem der_cert;
+  der_cert.type = siDERCertBuffer;
+  // Make a copy of certificate string so it is safe to type cast.
+  der_cert.data =
+      reinterpret_cast<unsigned char*>(const_cast<char*>(device_cert.data()));
+  der_cert.len = device_cert.length();
+
+  // Parse into a certificate structure.
+  ScopedCERTCertificate cert(CERT_NewTempCertificate(
+      CERT_GetDefaultCertDB(), &der_cert, NULL, PR_FALSE, PR_TRUE));
+  if (!cert.get()) {
+    return VerificationResult("Failed to parse certificate.",
+                              VerificationResult::ERROR_CERT_PARSING_FAILED,
+                              PORT_GetError());
+  }
+
+  // Check that the certificate is signed by trusted CA.
+  // NOTE: We const_cast trusted_ca_key_der since on some platforms
+  // SECKEY_ImportDERPublicKey API takes in SECItem* and not const
+  // SECItem*.
+  crypto::ScopedSECKEYPublicKey ca_public_key(
+      SECKEY_ImportDERPublicKey(&trusted_ca_key_der, CKK_RSA));
+  if (!ca_public_key) {
+    return VerificationResult(
+        "Failed to import public key from CA certificate.",
+        VerificationResult::ERROR_CERT_PARSING_FAILED, PORT_GetError());
+  }
+  SECStatus verified = CERT_VerifySignedDataWithPublicKey(
+      &cert->signatureWrap, ca_public_key.get(), NULL);
+  if (verified != SECSuccess) {
+    return VerificationResult(
+        "Cert not signed by trusted CA",
+        VerificationResult::ERROR_CERT_NOT_SIGNED_BY_TRUSTED_CA,
+        PORT_GetError());
+  }
+
+  VLOG(1) << "Cert signed by trusted CA";

[Ryan Sleevi, 2014/12/15 21:43:00]

SPAM: This is also spammy. Considering you don't log the early returns (101-103,
124-126), this also doesn't tell meaningful information - it still forces an
inference.

But just get rid of it.

[sheretov, 2014/12/16 08:44:21]

Done.

+
+  if (out_context)
+    *out_context = new CertVerificationContextNSS(cert.release());
+
+  return VerificationResult();
+}
+
+}  // namespace cast_crypto
+}  // namespace core_api
+}  // namespace extensions