Botan  2.4.0
Crypto and TLS for C++11
pem.cpp
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1 /*
2 * PEM Encoding/Decoding
3 * (C) 1999-2007 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/pem.h>
9 #include <botan/data_src.h>
10 #include <botan/base64.h>
11 #include <botan/exceptn.h>
12 
13 namespace Botan {
14 
15 namespace PEM_Code {
16 
17 namespace {
18 
19 std::string linewrap(size_t width, const std::string& in)
20  {
21  std::string out;
22  for(size_t i = 0; i != in.size(); ++i)
23  {
24  if(i > 0 && i % width == 0)
25  {
26  out.push_back('\n');
27  }
28  out.push_back(in[i]);
29  }
30  if(out.size() > 0 && out[out.size()-1] != '\n')
31  {
32  out.push_back('\n');
33  }
34 
35  return out;
36  }
37 
38 }
39 
40 /*
41 * PEM encode BER/DER-encoded objects
42 */
43 std::string encode(const uint8_t der[], size_t length, const std::string& label, size_t width)
44  {
45  const std::string PEM_HEADER = "-----BEGIN " + label + "-----\n";
46  const std::string PEM_TRAILER = "-----END " + label + "-----\n";
47 
48  return (PEM_HEADER + linewrap(width, base64_encode(der, length)) + PEM_TRAILER);
49  }
50 
51 /*
52 * Decode PEM down to raw BER/DER
53 */
55  const std::string& label_want)
56  {
57  std::string label_got;
58  secure_vector<uint8_t> ber = decode(source, label_got);
59  if(label_got != label_want)
60  throw Decoding_Error("PEM: Label mismatch, wanted " + label_want +
61  ", got " + label_got);
62  return ber;
63  }
64 
65 /*
66 * Decode PEM down to raw BER/DER
67 */
68 secure_vector<uint8_t> decode(DataSource& source, std::string& label)
69  {
70  const size_t RANDOM_CHAR_LIMIT = 8;
71 
72  label.clear();
73 
74  const std::string PEM_HEADER1 = "-----BEGIN ";
75  const std::string PEM_HEADER2 = "-----";
76  size_t position = 0;
77 
78  while(position != PEM_HEADER1.length())
79  {
80  uint8_t b;
81  if(!source.read_byte(b))
82  throw Decoding_Error("PEM: No PEM header found");
83  if(b == PEM_HEADER1[position])
84  ++position;
85  else if(position >= RANDOM_CHAR_LIMIT)
86  throw Decoding_Error("PEM: Malformed PEM header");
87  else
88  position = 0;
89  }
90  position = 0;
91  while(position != PEM_HEADER2.length())
92  {
93  uint8_t b;
94  if(!source.read_byte(b))
95  throw Decoding_Error("PEM: No PEM header found");
96  if(b == PEM_HEADER2[position])
97  ++position;
98  else if(position)
99  throw Decoding_Error("PEM: Malformed PEM header");
100 
101  if(position == 0)
102  label += static_cast<char>(b);
103  }
104 
105  std::vector<char> b64;
106 
107  const std::string PEM_TRAILER = "-----END " + label + "-----";
108  position = 0;
109  while(position != PEM_TRAILER.length())
110  {
111  uint8_t b;
112  if(!source.read_byte(b))
113  throw Decoding_Error("PEM: No PEM trailer found");
114  if(b == PEM_TRAILER[position])
115  ++position;
116  else if(position)
117  throw Decoding_Error("PEM: Malformed PEM trailer");
118 
119  if(position == 0)
120  b64.push_back(b);
121  }
122 
123  return base64_decode(b64.data(), b64.size());
124  }
125 
127  const std::string& label_want)
128  {
129  DataSource_Memory src(pem);
130  return decode_check_label(src, label_want);
131  }
132 
133 secure_vector<uint8_t> decode(const std::string& pem, std::string& label)
134  {
135  DataSource_Memory src(pem);
136  return decode(src, label);
137  }
138 
139 /*
140 * Search for a PEM signature
141 */
142 bool matches(DataSource& source, const std::string& extra,
143  size_t search_range)
144  {
145  const std::string PEM_HEADER = "-----BEGIN " + extra;
146 
147  secure_vector<uint8_t> search_buf(search_range);
148  size_t got = source.peek(search_buf.data(), search_buf.size(), 0);
149 
150  if(got < PEM_HEADER.length())
151  return false;
152 
153  size_t index = 0;
154 
155  for(size_t j = 0; j != got; ++j)
156  {
157  if(search_buf[j] == PEM_HEADER[index])
158  ++index;
159  else
160  index = 0;
161  if(index == PEM_HEADER.size())
162  return true;
163  }
164  return false;
165  }
166 
167 }
168 
169 }
secure_vector< uint8_t > decode_check_label(DataSource &source, const std::string &label_want)
Definition: pem.cpp:54
virtual size_t peek(uint8_t out[], size_t length, size_t peek_offset) const BOTAN_WARN_UNUSED_RESULT=0
std::string encode(const uint8_t der[], size_t length, const std::string &label, size_t width)
Definition: pem.cpp:43
size_t base64_encode(char out[], const uint8_t in[], size_t input_length, size_t &input_consumed, bool final_inputs)
Definition: base64.cpp:35
bool matches(DataSource &source, const std::string &extra, size_t search_range)
Definition: pem.cpp:142
size_t base64_decode(uint8_t output[], const char input[], size_t input_length, size_t &input_consumed, bool final_inputs, bool ignore_ws)
Definition: base64.cpp:100
secure_vector< uint8_t > decode(DataSource &source, std::string &label)
Definition: pem.cpp:68
Definition: alg_id.cpp:13
size_t read_byte(uint8_t &out)
Definition: data_src.cpp:23
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:88