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-rw-r--r--src/lib/rng/hmac_drbg/hmac_drbg.cpp12
-rw-r--r--src/lib/rng/stateful_rng/stateful_rng.h5
-rw-r--r--src/tests/test_rng.cpp18
3 files changed, 22 insertions, 13 deletions
diff --git a/src/lib/rng/hmac_drbg/hmac_drbg.cpp b/src/lib/rng/hmac_drbg/hmac_drbg.cpp
index e47d49628..03ea2013a 100644
--- a/src/lib/rng/hmac_drbg/hmac_drbg.cpp
+++ b/src/lib/rng/hmac_drbg/hmac_drbg.cpp
@@ -158,12 +158,18 @@ void HMAC_DRBG::update(const uint8_t input[], size_t input_len)
void HMAC_DRBG::add_entropy(const uint8_t input[], size_t input_len)
{
update(input, input_len);
+
+ if(8*input_len >= security_level())
+ {
+ m_reseed_counter = 1;
+ }
}
size_t HMAC_DRBG::security_level() const
{
- // sqrt of hash size
- return m_mac->output_length() * 8 / 2;
+ // security strength of the hash function
+ // for pre-image resistance (see NIST SP800-57),
+ // but NIST SP800-90A only supports up to 256 bits
+ return std::min(m_mac->output_length(), size_t(32)) * 8;
}
-
}
diff --git a/src/lib/rng/stateful_rng/stateful_rng.h b/src/lib/rng/stateful_rng/stateful_rng.h
index 982747e01..ed51aac6a 100644
--- a/src/lib/rng/stateful_rng/stateful_rng.h
+++ b/src/lib/rng/stateful_rng/stateful_rng.h
@@ -121,14 +121,15 @@ class BOTAN_DLL Stateful_RNG : public RandomNumberGenerator
Entropy_Sources* m_entropy_sources = nullptr;
const size_t m_reseed_interval;
+ uint32_t m_last_pid = 0;
+ protected:
/*
- * Set to 1 after a sucessful seeding, then incremented. Reset
+ * Set to 1 after a successful seeding, then incremented. Reset
* to 0 by clear() or a fork. This logic is used even if
* automatic reseeding is disabled (via m_reseed_interval = 0)
*/
size_t m_reseed_counter = 0;
- uint32_t m_last_pid = 0;
};
}
diff --git a/src/tests/test_rng.cpp b/src/tests/test_rng.cpp
index 0ebc091e2..3fb5bd461 100644
--- a/src/tests/test_rng.cpp
+++ b/src/tests/test_rng.cpp
@@ -144,16 +144,18 @@ class HMAC_DRBG_Unit_Tests : public Test
Request_Counting_RNG counting_rng;
Botan::HMAC_DRBG rng(std::move(mac), counting_rng, Botan::Entropy_Sources::global_sources(), 2);
Botan::secure_vector<uint8_t> seed_input(
- {0x00,0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,0x99,0xAA,0xBB,0xCC,0xDD,0xEE,0xFF});
+ {0x00,0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,0x99,0xAA,0xBB,0xCC,0xDD,0xEE,0xFF,
+ 0x00,0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,0x99,0xAA,0xBB,0xCC,0xDD,0xEE,0xFF});
Botan::secure_vector<uint8_t> output_after_initialization(
- {0x26,0x06,0x95,0xF4,0xB8,0x96,0x0D,0x0B,0x27,0x4E,0xA2,0x9E,0x8D,0x2B,0x5A,0x35});
+ {0x48,0xD3,0xB4,0x5A,0xAB,0x65,0xEF,0x92,0xCC,0xFC,0xB9,0x42,0x7E,0xF2,0x0C,0x90,
+ 0x29,0x70,0x65,0xEC,0xC1,0xB8,0xA5,0x25,0xBF,0xE4,0xDC,0x6F,0xF3,0x6D,0x0E,0x38});
Botan::secure_vector<uint8_t> output_without_reseed(
{0xC4,0x90,0x04,0x5B,0x35,0x4F,0x50,0x09,0x68,0x45,0xF0,0x4B,0x11,0x03,0x58,0xF0});
result.test_eq("is_seeded",rng.is_seeded(),false);
rng.initialize_with(seed_input.data(), seed_input.size());
- Botan::secure_vector<uint8_t> out(16);
+ Botan::secure_vector<uint8_t> out(32);
rng.randomize(out.data(), out.size());
result.test_eq("underlying RNG calls", counting_rng.randomize_count(), size_t(0));
@@ -337,8 +339,8 @@ class HMAC_DRBG_Unit_Tests : public Test
// make sure the nonce has at least 1/2*security_strength bits
- // SHA-256 -> 128 bits security strength
- for( auto nonce_size : { 0, 4, 15, 16, 17, 32 } )
+ // SHA-256 -> 256 bits security strength
+ for( auto nonce_size : { 0, 4, 8, 16, 31, 32, 34 } )
{
if(!mac)
{
@@ -350,15 +352,15 @@ class HMAC_DRBG_Unit_Tests : public Test
std::vector<uint8_t> nonce(nonce_size);
rng.initialize_with(nonce.data(), nonce.size());
- if(nonce_size < 16)
+ if(nonce_size < 32)
{
result.test_eq("not seeded", rng.is_seeded(), false);
- result.test_throws("invalid nonce size", [&rng, &nonce] () { rng.random_vec(16); });
+ result.test_throws("invalid nonce size", [&rng, &nonce] () { rng.random_vec(32); });
}
else
{
result.test_eq("is seeded", rng.is_seeded(), true);
- rng.random_vec(16);
+ rng.random_vec(32);
}
}