google_apis/cup/client_update_protocol_nss.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "google_apis/cup/client_update_protocol.h"
   6
   7 #include <keyhi.h>
   8 #include <pk11pub.h>
   9 #include <seccomon.h>
  10
  11 #include "base/logging.h"
  12 #include "crypto/nss_util.h"
  13 #include "crypto/scoped_nss_types.h"
  14
  15 typedef scoped_ptr<CERTSubjectPublicKeyInfo,
  16                    crypto::NSSDestroyer<CERTSubjectPublicKeyInfo,
  17                                         SECKEY_DestroySubjectPublicKeyInfo> >
  18     ScopedCERTSubjectPublicKeyInfo;
  19
  20 ClientUpdateProtocol::~ClientUpdateProtocol() {
  21   if (public_key_)
  22     SECKEY_DestroyPublicKey(public_key_);
  23 }
  24
  25 bool ClientUpdateProtocol::LoadPublicKey(const base::StringPiece& public_key) {
  26   crypto::EnsureNSSInit();
  27
  28   // The binary blob |public_key| is expected to be a DER-encoded ASN.1
  29   // Subject Public Key Info.
  30   SECItem spki_item;
  31   spki_item.type = siBuffer;
  32   spki_item.data =
  33       reinterpret_cast<unsigned char*>(const_cast<char*>(public_key.data()));
  34   spki_item.len = static_cast<unsigned int>(public_key.size());
  35
  36   ScopedCERTSubjectPublicKeyInfo spki(
  37       SECKEY_DecodeDERSubjectPublicKeyInfo(&spki_item));
  38   if (!spki.get())
  39     return false;
  40
  41   public_key_ = SECKEY_ExtractPublicKey(spki.get());
  42   if (!public_key_)
  43     return false;
  44
  45   if (!PublicKeyLength())
  46     return false;
  47
  48   return true;
  49 }
  50
  51 size_t ClientUpdateProtocol::PublicKeyLength() {
  52   if (!public_key_)
  53     return 0;
  54
  55   return SECKEY_PublicKeyStrength(public_key_);
  56 }
  57
  58 bool ClientUpdateProtocol::EncryptKeySource(
  59     const std::vector<uint8>& key_source) {
  60   // WARNING: This call bypasses the usual PKCS #1 padding and does direct RSA
  61   // exponentiation.  This is not secure without taking measures to ensure that
  62   // the contents of r are suitable.  This is done to remain compatible with
  63   // the implementation on the Google Update servers; don't copy-paste this
  64   // code arbitrarily and expect it to work and/or remain secure!
  65   if (!public_key_)
  66     return false;
  67
  68   size_t keysize = SECKEY_PublicKeyStrength(public_key_);
  69   if (key_source.size() != keysize)
  70     return false;
  71
  72   encrypted_key_source_.resize(keysize);
  73   return SECSuccess == PK11_PubEncryptRaw(
  74       public_key_,
  75       &encrypted_key_source_[0],
  76       const_cast<unsigned char*>(&key_source[0]),
  77       key_source.size(),
  78       NULL);
  79 }
  80