hmac-filter.cpp
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2013-2017 Regents of the University of California.
4  *
5  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
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21 
22 #include "hmac-filter.hpp"
23 #include "../detail/openssl-helper.hpp"
24 
25 #include <boost/lexical_cast.hpp>
26 
27 namespace ndn {
28 namespace security {
29 namespace transform {
30 
31 class HmacFilter::Impl
32 {
33 public:
34  Impl()
35  : key(nullptr)
36  {
37  }
38 
39  ~Impl()
40  {
41  EVP_PKEY_free(key);
42  }
43 
44 public:
45  detail::EvpMdCtx ctx;
46  EVP_PKEY* key;
47 };
48 
49 
50 HmacFilter::HmacFilter(DigestAlgorithm algo, const uint8_t* key, size_t keyLen)
51  : m_impl(make_unique<Impl>())
52 {
53  BOOST_ASSERT(key != nullptr);
54  BOOST_ASSERT(keyLen > 0);
55 
56  const EVP_MD* md = detail::digestAlgorithmToEvpMd(algo);
57  if (md == nullptr)
58  BOOST_THROW_EXCEPTION(Error(getIndex(), "Unsupported digest algorithm " +
59  boost::lexical_cast<std::string>(algo)));
60 
61  m_impl->key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, nullptr, key, static_cast<int>(keyLen));
62  if (m_impl->key == nullptr)
63  BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to create HMAC key"));
64 
65  if (EVP_DigestSignInit(m_impl->ctx, nullptr, md, nullptr, m_impl->key) != 1)
66  BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to initialize HMAC context with " +
67  boost::lexical_cast<std::string>(algo) + " digest"));
68 }
69 
70 HmacFilter::~HmacFilter() = default;
71 
72 size_t
73 HmacFilter::convert(const uint8_t* buf, size_t size)
74 {
75  if (EVP_DigestSignUpdate(m_impl->ctx, buf, size) != 1)
76  BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to accept more input"));
77 
78  return size;
79 }
80 
81 void
82 HmacFilter::finalize()
83 {
84  auto buffer = make_unique<OBuffer>(EVP_MAX_MD_SIZE);
85  size_t hmacLen = 0;
86 
87  if (EVP_DigestSignFinal(m_impl->ctx, buffer->data(), &hmacLen) != 1)
88  BOOST_THROW_EXCEPTION(Error(getIndex(), "Failed to finalize HMAC"));
89 
90  buffer->erase(buffer->begin() + hmacLen, buffer->end());
91  setOutputBuffer(std::move(buffer));
92 
94 }
95 
96 unique_ptr<Transform>
97 hmacFilter(DigestAlgorithm algo, const uint8_t* key, size_t keyLen)
98 {
99  return make_unique<HmacFilter>(algo, key, keyLen);
100 }
101 
102 } // namespace transform
103 } // namespace security
104 } // namespace ndn
Copyright (c) 2013-2017 Regents of the University of California.
Definition: common.hpp:66
unique_ptr< T > make_unique(Args &&...args)
Definition: backports.hpp:73
unique_ptr< Transform > hmacFilter(DigestAlgorithm algo, const uint8_t *key, size_t keyLen)
Definition: hmac-filter.cpp:97
void flushAllOutput()
Read the all the content from output buffer and write it into next module.
void setOutputBuffer(unique_ptr< OBuffer > buffer)
Set output buffer to buffer.
Base class of transformation error.
HmacFilter(DigestAlgorithm algo, const uint8_t *key, size_t keyLen)
Create a module to generate HMAC using digest algorithm algo and key key.
Definition: hmac-filter.cpp:50
size_t getIndex() const
Get the module index.