Botan  2.7.0
Crypto and TLS for C++11
cipher_mode.cpp
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1 /*
2 * Cipher Modes
3 * (C) 2015 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/cipher_mode.h>
9 #include <botan/stream_mode.h>
10 #include <botan/scan_name.h>
11 #include <botan/parsing.h>
12 #include <sstream>
13 
14 #if defined(BOTAN_HAS_BLOCK_CIPHER)
15  #include <botan/block_cipher.h>
16 #endif
17 
18 #if defined(BOTAN_HAS_AEAD_MODES)
19  #include <botan/aead.h>
20 #endif
21 
22 #if defined(BOTAN_HAS_MODE_CBC)
23  #include <botan/cbc.h>
24 #endif
25 
26 #if defined(BOTAN_HAS_MODE_CFB)
27  #include <botan/cfb.h>
28 #endif
29 
30 #if defined(BOTAN_HAS_MODE_XTS)
31  #include <botan/xts.h>
32 #endif
33 
34 #if defined(BOTAN_HAS_OPENSSL)
35  #include <botan/internal/openssl.h>
36 #endif
37 
38 namespace Botan {
39 
40 std::unique_ptr<Cipher_Mode> Cipher_Mode::create_or_throw(const std::string& algo,
41  Cipher_Dir direction,
42  const std::string& provider)
43  {
44  if(auto mode = Cipher_Mode::create(algo, direction, provider))
45  return mode;
46 
47  throw Lookup_Error("Cipher mode", algo, provider);
48  }
49 
50 std::unique_ptr<Cipher_Mode> Cipher_Mode::create(const std::string& algo,
51  Cipher_Dir direction,
52  const std::string& provider)
53  {
54 #if defined(BOTAN_HAS_OPENSSL)
55  if(provider.empty() || provider == "openssl")
56  {
57  std::unique_ptr<Cipher_Mode> openssl_cipher(make_openssl_cipher_mode(algo, direction));
58 
59  if(openssl_cipher)
60  return openssl_cipher;
61 
62  if(!provider.empty())
63  return std::unique_ptr<Cipher_Mode>();
64  }
65 #endif
66 
67 #if defined(BOTAN_HAS_STREAM_CIPHER)
68  if(auto sc = StreamCipher::create(algo))
69  {
70  return std::unique_ptr<Cipher_Mode>(new Stream_Cipher_Mode(sc.release()));
71  }
72 #endif
73 
74 #if defined(BOTAN_HAS_AEAD_MODES)
75  if(auto aead = AEAD_Mode::create(algo, direction))
76  {
77  return std::unique_ptr<Cipher_Mode>(aead.release());
78  }
79 #endif
80 
81  if(algo.find('/') != std::string::npos)
82  {
83  const std::vector<std::string> algo_parts = split_on(algo, '/');
84  const std::string cipher_name = algo_parts[0];
85  const std::vector<std::string> mode_info = parse_algorithm_name(algo_parts[1]);
86 
87  if(mode_info.empty())
88  return std::unique_ptr<Cipher_Mode>();
89 
90  std::ostringstream alg_args;
91 
92  alg_args << '(' << cipher_name;
93  for(size_t i = 1; i < mode_info.size(); ++i)
94  alg_args << ',' << mode_info[i];
95  for(size_t i = 2; i < algo_parts.size(); ++i)
96  alg_args << ',' << algo_parts[i];
97  alg_args << ')';
98 
99  const std::string mode_name = mode_info[0] + alg_args.str();
100  return Cipher_Mode::create(mode_name, direction, provider);
101  }
102 
103 #if defined(BOTAN_HAS_BLOCK_CIPHER)
104 
105  SCAN_Name spec(algo);
106 
107  if(spec.arg_count() == 0)
108  {
109  return std::unique_ptr<Cipher_Mode>();
110  }
111 
112  std::unique_ptr<BlockCipher> bc(BlockCipher::create(spec.arg(0), provider));
113 
114  if(!bc)
115  {
116  return std::unique_ptr<Cipher_Mode>();
117  }
118 
119 #if defined(BOTAN_HAS_MODE_CBC)
120  if(spec.algo_name() == "CBC")
121  {
122  const std::string padding = spec.arg(1, "PKCS7");
123 
124  if(padding == "CTS")
125  {
126  if(direction == ENCRYPTION)
127  return std::unique_ptr<Cipher_Mode>(new CTS_Encryption(bc.release()));
128  else
129  return std::unique_ptr<Cipher_Mode>(new CTS_Decryption(bc.release()));
130  }
131  else
132  {
133  std::unique_ptr<BlockCipherModePaddingMethod> pad(get_bc_pad(padding));
134 
135  if(pad)
136  {
137  if(direction == ENCRYPTION)
138  return std::unique_ptr<Cipher_Mode>(new CBC_Encryption(bc.release(), pad.release()));
139  else
140  return std::unique_ptr<Cipher_Mode>(new CBC_Decryption(bc.release(), pad.release()));
141  }
142  }
143  }
144 #endif
145 
146 #if defined(BOTAN_HAS_MODE_XTS)
147  if(spec.algo_name() == "XTS")
148  {
149  if(direction == ENCRYPTION)
150  return std::unique_ptr<Cipher_Mode>(new XTS_Encryption(bc.release()));
151  else
152  return std::unique_ptr<Cipher_Mode>(new XTS_Decryption(bc.release()));
153  }
154 #endif
155 
156 #if defined(BOTAN_HAS_MODE_CFB)
157  if(spec.algo_name() == "CFB")
158  {
159  const size_t feedback_bits = spec.arg_as_integer(1, 8*bc->block_size());
160  if(direction == ENCRYPTION)
161  return std::unique_ptr<Cipher_Mode>(new CFB_Encryption(bc.release(), feedback_bits));
162  else
163  return std::unique_ptr<Cipher_Mode>(new CFB_Decryption(bc.release(), feedback_bits));
164  }
165 #endif
166 
167 #endif
168 
169  return std::unique_ptr<Cipher_Mode>();
170  }
171 
172 //static
173 std::vector<std::string> Cipher_Mode::providers(const std::string& algo_spec)
174  {
175  const std::vector<std::string>& possible = { "base", "openssl" };
176  std::vector<std::string> providers;
177  for(auto&& prov : possible)
178  {
179  std::unique_ptr<Cipher_Mode> mode = Cipher_Mode::create(algo_spec, ENCRYPTION, prov);
180  if(mode)
181  {
182  providers.push_back(prov); // available
183  }
184  }
185  return providers;
186  }
187 
188 }
size_t arg_count() const
Definition: scan_name.h:49
std::vector< std::string > split_on(const std::string &str, char delim)
Definition: parsing.cpp:144
size_t arg_as_integer(size_t i, size_t def_value) const
Definition: scan_name.cpp:137
Cipher_Mode * make_openssl_cipher_mode(const std::string &name, Cipher_Dir direction)
std::string arg(size_t i) const
Definition: scan_name.cpp:122
static std::unique_ptr< AEAD_Mode > create(const std::string &algo, Cipher_Dir direction, const std::string &provider="")
Definition: aead.cpp:52
std::vector< std::string > parse_algorithm_name(const std::string &namex)
Definition: parsing.cpp:91
Definition: alg_id.cpp:13
static std::unique_ptr< BlockCipher > create(const std::string &algo_spec, const std::string &provider="")
const std::string & algo_name() const
Definition: scan_name.h:44
static std::unique_ptr< Cipher_Mode > create(const std::string &algo, Cipher_Dir direction, const std::string &provider="")
Definition: cipher_mode.cpp:50
Cipher_Dir
Definition: cipher_mode.h:24
static std::vector< std::string > providers(const std::string &algo_spec)
static std::unique_ptr< StreamCipher > create(const std::string &algo_spec, const std::string &provider="")
static std::unique_ptr< Cipher_Mode > create_or_throw(const std::string &algo, Cipher_Dir direction, const std::string &provider="")
Definition: cipher_mode.cpp:40
virtual std::string provider() const
Definition: cipher_mode.h:236
BlockCipherModePaddingMethod * get_bc_pad(const std::string &algo_spec)
Definition: mode_pad.cpp:18