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/*
* Bcrypt Password Hashing
* (C) 2010,2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/bcrypt.h>
#include <botan/rng.h>
#include <botan/internal/blowfish.h>
#include <botan/base64.h>
#include <botan/internal/parsing.h>
namespace Botan {
namespace {
// Bcrypt uses a non-standard base64 alphabet
alignas(256) const uint8_t OPENBSD_BASE64_SUB[256] = {
0x00, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x38, 0x80, 0x80, 0x80, 0x39,
0x79, 0x7A, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x2E, 0x2F, 0x41, 0x42, 0x43, 0x44, 0x45,
0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51,
0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75,
0x76, 0x77, 0x78, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80
};
alignas(256) const uint8_t OPENBSD_BASE64_SUB_INV[256] = {
0x00, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x41, 0x42,
0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55,
0x56, 0x57, 0x58, 0x59, 0x5A, 0x61, 0x62, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D,
0x6E, 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7A, 0x30, 0x31, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,
0x80, 0x80, 0x80, 0x80
};
std::string bcrypt_base64_encode(const uint8_t input[], size_t length)
{
std::string b64 = base64_encode(input, length);
while(b64.size() && b64[b64.size()-1] == '=')
b64 = b64.substr(0, b64.size() - 1);
for(size_t i = 0; i != b64.size(); ++i)
b64[i] = OPENBSD_BASE64_SUB[static_cast<uint8_t>(b64[i])];
return b64;
}
std::vector<uint8_t> bcrypt_base64_decode(std::string input)
{
for(size_t i = 0; i != input.size(); ++i)
input[i] = OPENBSD_BASE64_SUB_INV[static_cast<uint8_t>(input[i])];
return unlock(base64_decode(input));
}
std::string make_bcrypt(const std::string& pass,
const std::vector<uint8_t>& salt,
uint16_t work_factor,
char version)
{
/*
* On a 4 GHz Skylake, workfactor == 18 takes about 15 seconds to
* hash a password. This seems like a reasonable upper bound for the
* time being.
* Bcrypt allows up to work factor 31 (2^31 iterations)
*/
BOTAN_ARG_CHECK(work_factor >= 4 && work_factor <= 18,
"Invalid bcrypt work factor");
static const uint8_t BCRYPT_MAGIC[8*3] = {
0x4F, 0x72, 0x70, 0x68, 0x65, 0x61, 0x6E, 0x42,
0x65, 0x68, 0x6F, 0x6C, 0x64, 0x65, 0x72, 0x53,
0x63, 0x72, 0x79, 0x44, 0x6F, 0x75, 0x62, 0x74
};
Blowfish blowfish;
// Include the trailing NULL byte, so we need c_str() not data()
blowfish.salted_set_key(cast_char_ptr_to_uint8(pass.c_str()),
pass.length() + 1,
salt.data(),
salt.size(),
work_factor);
std::vector<uint8_t> ctext(BCRYPT_MAGIC, BCRYPT_MAGIC + 8*3);
for(size_t i = 0; i != 64; ++i)
blowfish.encrypt_n(ctext.data(), ctext.data(), 3);
std::string salt_b64 = bcrypt_base64_encode(salt.data(), salt.size());
std::string work_factor_str = std::to_string(work_factor);
if(work_factor_str.length() == 1)
work_factor_str = "0" + work_factor_str;
return "$2" + std::string(1, version) + "$" + work_factor_str +
"$" + salt_b64.substr(0, 22) +
bcrypt_base64_encode(ctext.data(), ctext.size() - 1);
}
}
std::string generate_bcrypt(const std::string& pass,
RandomNumberGenerator& rng,
uint16_t work_factor,
char version)
{
/*
2a, 2b and 2y are identical for our purposes because our implementation of 2a
never had the truncation or signed char bugs in the first place.
*/
if(version != 'a' && version != 'b' && version != 'y')
throw Invalid_Argument("Unknown bcrypt version '" + std::string(1, version) + "'");
std::vector<uint8_t> salt;
rng.random_vec(salt, 16);
return make_bcrypt(pass, salt, work_factor, version);
}
bool check_bcrypt(const std::string& pass, const std::string& hash)
{
if(hash.size() != 60 ||
hash[0] != '$' || hash[1] != '2' || hash[3] != '$' || hash[6] != '$')
{
return false;
}
const char bcrypt_version = hash[2];
if(bcrypt_version != 'a' && bcrypt_version != 'b' && bcrypt_version != 'y')
{
return false;
}
const uint16_t workfactor = to_uint16(hash.substr(4, 2));
const std::vector<uint8_t> salt = bcrypt_base64_decode(hash.substr(7, 22));
if(salt.size() != 16)
return false;
const std::string compare = make_bcrypt(pass, salt, workfactor, bcrypt_version);
return same_mem(hash.data(), compare.data(), compare.size());
}
}
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