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/*
* PEM Encoding/Decoding
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/pem.h>
#include <botan/base64.h>
#include <botan/parsing.h>
#include <botan/exceptn.h>
namespace Botan {
namespace PEM_Code {
namespace {
std::string linewrap(size_t width, const std::string& in)
{
std::string out;
for(size_t i = 0; i != in.size(); ++i)
{
if(i > 0 && i % width == 0)
{
out.push_back('\n');
}
out.push_back(in[i]);
}
if(out.size() > 0 && out[out.size()-1] != '\n')
{
out.push_back('\n');
}
return out;
}
}
/*
* PEM encode BER/DER-encoded objects
*/
std::string encode(const byte der[], size_t length, const std::string& label, size_t width)
{
const std::string PEM_HEADER = "-----BEGIN " + label + "-----\n";
const std::string PEM_TRAILER = "-----END " + label + "-----\n";
return (PEM_HEADER + linewrap(width, base64_encode(der, length)) + PEM_TRAILER);
}
/*
* Decode PEM down to raw BER/DER
*/
secure_vector<byte> decode_check_label(DataSource& source,
const std::string& label_want)
{
std::string label_got;
secure_vector<byte> ber = decode(source, label_got);
if(label_got != label_want)
throw Decoding_Error("PEM: Label mismatch, wanted " + label_want +
", got " + label_got);
return ber;
}
/*
* Decode PEM down to raw BER/DER
*/
secure_vector<byte> decode(DataSource& source, std::string& label)
{
const size_t RANDOM_CHAR_LIMIT = 8;
const std::string PEM_HEADER1 = "-----BEGIN ";
const std::string PEM_HEADER2 = "-----";
size_t position = 0;
while(position != PEM_HEADER1.length())
{
byte b;
if(!source.read_byte(b))
throw Decoding_Error("PEM: No PEM header found");
if(b == PEM_HEADER1[position])
++position;
else if(position >= RANDOM_CHAR_LIMIT)
throw Decoding_Error("PEM: Malformed PEM header");
else
position = 0;
}
position = 0;
while(position != PEM_HEADER2.length())
{
byte b;
if(!source.read_byte(b))
throw Decoding_Error("PEM: No PEM header found");
if(b == PEM_HEADER2[position])
++position;
else if(position)
throw Decoding_Error("PEM: Malformed PEM header");
if(position == 0)
label += static_cast<char>(b);
}
std::vector<char> b64;
const std::string PEM_TRAILER = "-----END " + label + "-----";
position = 0;
while(position != PEM_TRAILER.length())
{
byte b;
if(!source.read_byte(b))
throw Decoding_Error("PEM: No PEM trailer found");
if(b == PEM_TRAILER[position])
++position;
else if(position)
throw Decoding_Error("PEM: Malformed PEM trailer");
if(position == 0)
b64.push_back(b);
}
return base64_decode(b64.data(), b64.size());
}
secure_vector<byte> decode_check_label(const std::string& pem,
const std::string& label_want)
{
DataSource_Memory src(pem);
return decode_check_label(src, label_want);
}
secure_vector<byte> decode(const std::string& pem, std::string& label)
{
DataSource_Memory src(pem);
return decode(src, label);
}
/*
* Search for a PEM signature
*/
bool matches(DataSource& source, const std::string& extra,
size_t search_range)
{
const std::string PEM_HEADER = "-----BEGIN " + extra;
secure_vector<byte> search_buf(search_range);
size_t got = source.peek(search_buf.data(), search_buf.size(), 0);
if(got < PEM_HEADER.length())
return false;
size_t index = 0;
for(size_t j = 0; j != got; ++j)
{
if(search_buf[j] == PEM_HEADER[index])
++index;
else
index = 0;
if(index == PEM_HEADER.size())
return true;
}
return false;
}
}
}
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