diff options
Diffstat (limited to 'src/lib/pbkdf/pbkdf2/pbkdf2.cpp')
| -rw-r--r-- | src/lib/pbkdf/pbkdf2/pbkdf2.cpp | 224 |
1 files changed, 164 insertions, 60 deletions
diff --git a/src/lib/pbkdf/pbkdf2/pbkdf2.cpp b/src/lib/pbkdf/pbkdf2/pbkdf2.cpp index cc2982f6e..65e8a9503 100644 --- a/src/lib/pbkdf/pbkdf2/pbkdf2.cpp +++ b/src/lib/pbkdf/pbkdf2/pbkdf2.cpp @@ -1,6 +1,7 @@ /* * PBKDF2 * (C) 1999-2007 Jack Lloyd +* (C) 2018 Ribose Inc * * Botan is released under the Simplified BSD License (see license.txt) */ @@ -8,41 +9,115 @@ #include <botan/pbkdf2.h> #include <botan/exceptn.h> #include <botan/internal/rounding.h> +#include <botan/internal/timer.h> namespace Botan { +namespace { + +void pbkdf2_set_key(MessageAuthenticationCode& prf, + const char* password, + size_t password_len) + { + try + { + prf.set_key(cast_char_ptr_to_uint8(password), password_len); + } + catch(Invalid_Key_Length&) + { + throw Exception("PBKDF2 cannot accept passphrase of the given size"); + } + } + +} + size_t pbkdf2(MessageAuthenticationCode& prf, uint8_t out[], size_t out_len, - const std::string& passphrase, + const std::string& password, const uint8_t salt[], size_t salt_len, size_t iterations, std::chrono::milliseconds msec) { - clear_mem(out, out_len); - - if(out_len == 0) - return 0; - - try + if(iterations == 0) { - prf.set_key(cast_char_ptr_to_uint8(passphrase.data()), passphrase.size()); - } - catch(Invalid_Key_Length&) - { - throw Exception("PBKDF2 with " + prf.name() + - " cannot accept passphrases of length " + - std::to_string(passphrase.size())); + iterations = PBKDF2(prf, out_len, msec).iterations(); } + PBKDF2 pbkdf2(prf, iterations); + + pbkdf2.derive_key(out, out_len, + password.c_str(), password.size(), + salt, salt_len); + + return iterations; + } + +namespace { + +size_t tune_pbkdf2(MessageAuthenticationCode& prf, + size_t output_length, + uint32_t msec) + { const size_t prf_sz = prf.output_length(); + BOTAN_ASSERT_NOMSG(prf_sz > 0); secure_vector<uint8_t> U(prf_sz); - const size_t blocks_needed = round_up(out_len, prf_sz) / prf_sz; + const size_t trial_iterations = 10000; + + // Short output ensures we only need a single PBKDF2 block + + Timer timer("PBKDF2"); + + const std::chrono::milliseconds tune_msec(30); + + prf.set_key(nullptr, 0); + + timer.run_until_elapsed(tune_msec, [&]() { + uint8_t out[16] = { 0 }; + uint8_t salt[16] = { 0 }; + pbkdf2(prf, out, sizeof(out), salt, sizeof(salt), trial_iterations); + }); + + if(timer.events() == 0) + return trial_iterations; + + const uint64_t duration_nsec = timer.value() / timer.events(); + + const uint64_t desired_nsec = static_cast<uint64_t>(msec) * 1000000; + + if(duration_nsec > desired_nsec) + return trial_iterations; + + const size_t blocks_needed = (output_length + prf_sz - 1) / prf_sz; + + const size_t multiplier = (desired_nsec / duration_nsec / blocks_needed); + + if(multiplier == 0) + return trial_iterations; + else + return trial_iterations * multiplier; + } + +} + +void pbkdf2(MessageAuthenticationCode& prf, + uint8_t out[], + size_t out_len, + const uint8_t salt[], + size_t salt_len, + size_t iterations) + { + clear_mem(out, out_len); + + if(out_len == 0) + return; + + const size_t prf_sz = prf.output_length(); + BOTAN_ASSERT_NOMSG(prf_sz > 0); - std::chrono::microseconds usec_per_block = - std::chrono::duration_cast<std::chrono::microseconds>(msec) / blocks_needed; + secure_vector<uint8_t> U(prf_sz); uint32_t counter = 1; while(out_len) @@ -55,64 +130,93 @@ pbkdf2(MessageAuthenticationCode& prf, xor_buf(out, U.data(), prf_output); - if(iterations == 0) + for(size_t i = 1; i != iterations; ++i) { - /* - If no iterations set, run the first block to calibrate based - on how long hashing takes on whatever machine we're running on. - */ - - const auto start = std::chrono::high_resolution_clock::now(); - - iterations = 1; // the first iteration we did above - - while(true) - { - prf.update(U); - prf.final(U.data()); - xor_buf(out, U.data(), prf_output); - iterations++; - - /* - Only break on relatively 'even' iterations. For one it - avoids confusion, and likely some broken implementations - break on getting completely randomly distributed values - */ - if(iterations % 10000 == 0) - { - auto time_taken = std::chrono::high_resolution_clock::now() - start; - auto usec_taken = std::chrono::duration_cast<std::chrono::microseconds>(time_taken); - if(usec_taken > usec_per_block) - break; - } - } - } - else - { - for(size_t i = 1; i != iterations; ++i) - { - prf.update(U); - prf.final(U.data()); - xor_buf(out, U.data(), prf_output); - } + prf.update(U); + prf.final(U.data()); + xor_buf(out, U.data(), prf_output); } out_len -= prf_output; out += prf_output; } - - return iterations; } +// PBKDF interface size_t PKCS5_PBKDF2::pbkdf(uint8_t key[], size_t key_len, - const std::string& passphrase, + const std::string& password, const uint8_t salt[], size_t salt_len, size_t iterations, std::chrono::milliseconds msec) const { - return pbkdf2(*m_mac.get(), key, key_len, passphrase, salt, salt_len, iterations, msec); + if(iterations == 0) + { + iterations = PBKDF2(*m_mac, key_len, msec).iterations(); + } + + PBKDF2 pbkdf2(*m_mac, iterations); + + pbkdf2.derive_key(key, key_len, + password.c_str(), password.size(), + salt, salt_len); + + return iterations; + } + +std::string PKCS5_PBKDF2::name() const + { + return "PBKDF2(" + m_mac->name() + ")"; + } + +PBKDF* PKCS5_PBKDF2::clone() const + { + return new PKCS5_PBKDF2(m_mac->clone()); } +// PasswordHash interface + +PBKDF2::PBKDF2(const MessageAuthenticationCode& prf, size_t olen, std::chrono::milliseconds msec) : + m_prf(prf.clone()), + m_iterations(tune_pbkdf2(*m_prf, olen, msec.count())) + {} + +std::string PBKDF2::to_string() const + { + return "PBKDF2(" + m_prf->name() + "," + std::to_string(m_iterations) + ")"; + } + +void PBKDF2::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 + { + pbkdf2_set_key(*m_prf, password, password_len); + pbkdf2(*m_prf, out, out_len, salt, salt_len, m_iterations); + } + +std::string PBKDF2_Family::name() const + { + return "PBKDF2(" + m_prf->name() + ")"; + } + +std::unique_ptr<PasswordHash> PBKDF2_Family::tune(size_t output_len, std::chrono::milliseconds msec, size_t) const + { + return std::unique_ptr<PasswordHash>(new PBKDF2(*m_prf, output_len, msec)); + } + +std::unique_ptr<PasswordHash> PBKDF2_Family::default_params() const + { + return std::unique_ptr<PasswordHash>(new PBKDF2(*m_prf, 150000)); + } + +std::unique_ptr<PasswordHash> PBKDF2_Family::from_params(size_t iter, size_t, size_t) const + { + return std::unique_ptr<PasswordHash>(new PBKDF2(*m_prf, iter)); + } + +std::unique_ptr<PasswordHash> PBKDF2_Family::from_iterations(size_t iter) const + { + return std::unique_ptr<PasswordHash>(new PBKDF2(*m_prf, iter)); + } } |