Botan  1.10.9
pem.cpp
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1 /*
2 * PEM Encoding/Decoding
3 * (C) 1999-2007 Jack Lloyd
4 *
5 * Distributed under the terms of the Botan license
6 */
7 
8 #include <botan/pem.h>
9 #include <botan/filters.h>
10 #include <botan/parsing.h>
11 
12 namespace Botan {
13 
14 namespace PEM_Code {
15 
16 /*
17 * PEM encode BER/DER-encoded objects
18 */
19 std::string encode(const byte der[], size_t length, const std::string& label,
20  size_t width)
21  {
22  const std::string PEM_HEADER = "-----BEGIN " + label + "-----\n";
23  const std::string PEM_TRAILER = "-----END " + label + "-----\n";
24 
25  Pipe pipe(new Base64_Encoder(true, width));
26  pipe.process_msg(der, length);
27  return (PEM_HEADER + pipe.read_all_as_string() + PEM_TRAILER);
28  }
29 
30 /*
31 * PEM encode BER/DER-encoded objects
32 */
33 std::string encode(const MemoryRegion<byte>& data, const std::string& label,
34  size_t width)
35  {
36  return encode(&data[0], data.size(), label, width);
37  }
38 
39 /*
40 * Decode PEM down to raw BER/DER
41 */
43  const std::string& label_want)
44  {
45  std::string label_got;
46  SecureVector<byte> ber = decode(source, label_got);
47  if(label_got != label_want)
48  throw Decoding_Error("PEM: Label mismatch, wanted " + label_want +
49  ", got " + label_got);
50  return ber;
51  }
52 
53 /*
54 * Decode PEM down to raw BER/DER
55 */
56 SecureVector<byte> decode(DataSource& source, std::string& label)
57  {
58  const size_t RANDOM_CHAR_LIMIT = 8;
59 
60  const std::string PEM_HEADER1 = "-----BEGIN ";
61  const std::string PEM_HEADER2 = "-----";
62  size_t position = 0;
63 
64  while(position != PEM_HEADER1.length())
65  {
66  byte b;
67  if(!source.read_byte(b))
68  throw Decoding_Error("PEM: No PEM header found");
69  if(b == PEM_HEADER1[position])
70  ++position;
71  else if(position >= RANDOM_CHAR_LIMIT)
72  throw Decoding_Error("PEM: Malformed PEM header");
73  else
74  position = 0;
75  }
76  position = 0;
77  while(position != PEM_HEADER2.length())
78  {
79  byte b;
80  if(!source.read_byte(b))
81  throw Decoding_Error("PEM: No PEM header found");
82  if(b == PEM_HEADER2[position])
83  ++position;
84  else if(position)
85  throw Decoding_Error("PEM: Malformed PEM header");
86 
87  if(position == 0)
88  label += static_cast<char>(b);
89  }
90 
91  Pipe base64(new Base64_Decoder);
92  base64.start_msg();
93 
94  const std::string PEM_TRAILER = "-----END " + label + "-----";
95  position = 0;
96  while(position != PEM_TRAILER.length())
97  {
98  byte b;
99  if(!source.read_byte(b))
100  throw Decoding_Error("PEM: No PEM trailer found");
101  if(b == PEM_TRAILER[position])
102  ++position;
103  else if(position)
104  throw Decoding_Error("PEM: Malformed PEM trailer");
105 
106  if(position == 0)
107  base64.write(b);
108  }
109  base64.end_msg();
110  return base64.read_all();
111  }
112 
113 /*
114 * Search for a PEM signature
115 */
116 bool matches(DataSource& source, const std::string& extra,
117  size_t search_range)
118  {
119  const std::string PEM_HEADER = "-----BEGIN " + extra;
120 
121  SecureVector<byte> search_buf(search_range);
122  size_t got = source.peek(&search_buf[0], search_buf.size(), 0);
123 
124  if(got < PEM_HEADER.length())
125  return false;
126 
127  size_t index = 0;
128 
129  for(size_t j = 0; j != got; ++j)
130  {
131  if(search_buf[j] == PEM_HEADER[index])
132  ++index;
133  else
134  index = 0;
135  if(index == PEM_HEADER.size())
136  return true;
137  }
138  return false;
139  }
140 
141 }
142 
143 }
void start_msg()
Definition: pipe.cpp:152
std::string read_all_as_string(message_id=DEFAULT_MESSAGE)
Definition: pipe_rw.cpp:117
void write(const byte in[], size_t length)
Definition: pipe_rw.cpp:34
unsigned char byte
Definition: types.h:22
SecureVector< byte > decode(DataSource &source, std::string &label)
Definition: pem.cpp:56
void end_msg()
Definition: pipe.cpp:166
SecureVector< byte > read_all(message_id msg=DEFAULT_MESSAGE)
Definition: pipe_rw.cpp:105
virtual size_t peek(byte out[], size_t length, size_t peek_offset) const =0
size_t read_byte(byte &out)
Definition: data_src.cpp:19
size_t size() const
Definition: secmem.h:29
bool matches(DataSource &source, const std::string &extra, size_t search_range)
Definition: pem.cpp:116
std::string encode(const byte der[], size_t length, const std::string &label, size_t width)
Definition: pem.cpp:19
SecureVector< byte > decode_check_label(DataSource &source, const std::string &label_want)
Definition: pem.cpp:42
void process_msg(const byte in[], size_t length)
Definition: pipe.cpp:116