/* * OpenPGP S2K * (C) 1999-2007,2017 Jack Lloyd * (C) 2018 Ribose Inc * * Distributed under the terms of the Botan license */ #include #include #include namespace Botan { uint8_t RFC4880_encode_count(size_t desired_iterations) { /* Only 256 different iterations are actually representable in OpenPGP format ... */ for(size_t c = 0; c < 256; ++c) { // TODO could binary search const size_t decoded_iter = RFC4880_decode_count(static_cast(c)); if(decoded_iter >= desired_iterations) return static_cast(c); } return 255; } size_t RFC4880_decode_count(uint8_t iter) { /* PGP stores the iteration count as a single byte Thus it can only actually take on one of 256 values, based on the formula in RFC 4880 section 3.6.1.3 */ static const uint32_t OPENPGP_S2K_ITERS[256] = { 1024, 1088, 1152, 1216, 1280, 1344, 1408, 1472, 1536, 1600, 1664, 1728, 1792, 1856, 1920, 1984, 2048, 2176, 2304, 2432, 2560, 2688, 2816, 2944, 3072, 3200, 3328, 3456, 3584, 3712, 3840, 3968, 4096, 4352, 4608, 4864, 5120, 5376, 5632, 5888, 6144, 6400, 6656, 6912, 7168, 7424, 7680, 7936, 8192, 8704, 9216, 9728, 10240, 10752, 11264, 11776, 12288, 12800, 13312, 13824, 14336, 14848, 15360, 15872, 16384, 17408, 18432, 19456, 20480, 21504, 22528, 23552, 24576, 25600, 26624, 27648, 28672, 29696, 30720, 31744, 32768, 34816, 36864, 38912, 40960, 43008, 45056, 47104, 49152, 51200, 53248, 55296, 57344, 59392, 61440, 63488, 65536, 69632, 73728, 77824, 81920, 86016, 90112, 94208, 98304, 102400, 106496, 110592, 114688, 118784, 122880, 126976, 131072, 139264, 147456, 155648, 163840, 172032, 180224, 188416, 196608, 204800, 212992, 221184, 229376, 237568, 245760, 253952, 262144, 278528, 294912, 311296, 327680, 344064, 360448, 376832, 393216, 409600, 425984, 442368, 458752, 475136, 491520, 507904, 524288, 557056, 589824, 622592, 655360, 688128, 720896, 753664, 786432, 819200, 851968, 884736, 917504, 950272, 983040, 1015808, 1048576, 1114112, 1179648, 1245184, 1310720, 1376256, 1441792, 1507328, 1572864, 1638400, 1703936, 1769472, 1835008, 1900544, 1966080, 2031616, 2097152, 2228224, 2359296, 2490368, 2621440, 2752512, 2883584, 3014656, 3145728, 3276800, 3407872, 3538944, 3670016, 3801088, 3932160, 4063232, 4194304, 4456448, 4718592, 4980736, 5242880, 5505024, 5767168, 6029312, 6291456, 6553600, 6815744, 7077888, 7340032, 7602176, 7864320, 8126464, 8388608, 8912896, 9437184, 9961472, 10485760, 11010048, 11534336, 12058624, 12582912, 13107200, 13631488, 14155776, 14680064, 15204352, 15728640, 16252928, 16777216, 17825792, 18874368, 19922944, 20971520, 22020096, 23068672, 24117248, 25165824, 26214400, 27262976, 28311552, 29360128, 30408704, 31457280, 32505856, 33554432, 35651584, 37748736, 39845888, 41943040, 44040192, 46137344, 48234496, 50331648, 52428800, 54525952, 56623104, 58720256, 60817408, 62914560, 65011712 }; return OPENPGP_S2K_ITERS[iter]; } namespace { void pgp_s2k(HashFunction& hash, uint8_t output_buf[], size_t output_len, const char* password, const size_t password_size, const uint8_t salt[], size_t salt_len, size_t iterations) { if(iterations > 1 && salt_len == 0) throw Invalid_Argument("OpenPGP S2K requires a salt in iterated mode"); secure_vector input_buf(salt_len + password_size); if(salt_len > 0) { copy_mem(&input_buf[0], salt, salt_len); } if(password_size > 0) { copy_mem(&input_buf[salt_len], cast_char_ptr_to_uint8(password), password_size); } secure_vector hash_buf(hash.output_length()); size_t pass = 0; size_t generated = 0; while(generated != output_len) { const size_t output_this_pass = std::min(hash_buf.size(), output_len - generated); // Preload some number of zero bytes (empty first iteration) std::vector zero_padding(pass); hash.update(zero_padding); // The input is always fully processed even if iterations is very small if(input_buf.empty() == false) { size_t left = std::max(iterations, input_buf.size()); while(left > 0) { const size_t input_to_take = std::min(left, input_buf.size()); hash.update(input_buf.data(), input_to_take); left -= input_to_take; } } hash.final(hash_buf.data()); copy_mem(output_buf + generated, hash_buf.data(), output_this_pass); generated += output_this_pass; ++pass; } } } size_t OpenPGP_S2K::pbkdf(uint8_t output_buf[], size_t output_len, const std::string& password, const uint8_t salt[], size_t salt_len, size_t iterations, std::chrono::milliseconds msec) const { std::unique_ptr pwdhash; if(iterations == 0) { RFC4880_S2K_Family s2k_params(m_hash->clone()); iterations = s2k_params.tune(output_len, msec, 0)->iterations(); } pgp_s2k(*m_hash, output_buf, output_len, password.c_str(), password.size(), salt, salt_len, iterations); return iterations; } std::string RFC4880_S2K_Family::name() const { return "OpenPGP-S2K(" + m_hash->name() + ")"; } std::unique_ptr RFC4880_S2K_Family::tune(size_t output_len, std::chrono::milliseconds msec, size_t) const { const std::chrono::milliseconds tune_time = std::chrono::milliseconds(30); const size_t buf_size = 1024; Botan::secure_vector buffer(buf_size); Timer timer("RFC4880_S2K", buf_size); timer.run_until_elapsed(tune_time, [&]() { m_hash->update(buffer); }); // bug in Timer::bytes_per_second? const double hash_bytes_per_second = buf_size * timer.bytes_per_second(); const uint64_t desired_nsec = msec.count() * 1000000; const size_t hash_size = m_hash->output_length(); const size_t blocks_required = (output_len <= hash_size ? 1 : (output_len + hash_size - 1) / hash_size); const double bytes_to_be_hashed = (hash_bytes_per_second * (desired_nsec / 1000000000.0)) / blocks_required; const size_t iterations = RFC4880_round_iterations(static_cast(bytes_to_be_hashed)); return std::unique_ptr(new RFC4880_S2K(m_hash->clone(), iterations)); } std::unique_ptr RFC4880_S2K_Family::from_params(size_t iter, size_t, size_t) const { return std::unique_ptr(new RFC4880_S2K(m_hash->clone(), iter)); } std::unique_ptr RFC4880_S2K_Family::default_params() const { return std::unique_ptr(new RFC4880_S2K(m_hash->clone(), 50331648)); } std::unique_ptr RFC4880_S2K_Family::from_iterations(size_t iter) const { return std::unique_ptr(new RFC4880_S2K(m_hash->clone(), iter)); } RFC4880_S2K::RFC4880_S2K(HashFunction* hash, size_t iterations) : m_hash(hash), m_iterations(iterations) { } std::string RFC4880_S2K::to_string() const { return "OpenPGP-S2K(" + m_hash->name() + "," + std::to_string(m_iterations) + ")"; } void RFC4880_S2K::derive_key(uint8_t out[], size_t out_len, const char* password, const size_t password_len, const uint8_t salt[], size_t salt_len) const { pgp_s2k(*m_hash, out, out_len, password, password_len, salt, salt_len, m_iterations); } }