diff options
-rw-r--r-- | src/random.cpp | 33 | ||||
-rw-r--r-- | src/random.h | 7 | ||||
-rw-r--r-- | src/scheduler.cpp | 6 |
3 files changed, 46 insertions, 0 deletions
diff --git a/src/random.cpp b/src/random.cpp index 3b9df3edaa..de7553c825 100644 --- a/src/random.cpp +++ b/src/random.cpp @@ -203,10 +203,43 @@ void GetRandBytes(unsigned char* buf, int num) } } +static void AddDataToRng(void* data, size_t len); + +void RandAddSeedSleep() +{ + int64_t nPerfCounter1 = GetPerformanceCounter(); + std::this_thread::sleep_for(std::chrono::milliseconds(1)); + int64_t nPerfCounter2 = GetPerformanceCounter(); + + // Combine with and update state + AddDataToRng(&nPerfCounter1, sizeof(nPerfCounter1)); + AddDataToRng(&nPerfCounter2, sizeof(nPerfCounter2)); + + memory_cleanse(&nPerfCounter1, sizeof(nPerfCounter1)); + memory_cleanse(&nPerfCounter2, sizeof(nPerfCounter2)); +} + + static std::mutex cs_rng_state; static unsigned char rng_state[32] = {0}; static uint64_t rng_counter = 0; +static void AddDataToRng(void* data, size_t len) { + CSHA512 hasher; + hasher.Write((const unsigned char*)&len, sizeof(len)); + hasher.Write((const unsigned char*)data, len); + unsigned char buf[64]; + { + std::unique_lock<std::mutex> lock(cs_rng_state); + hasher.Write(rng_state, sizeof(rng_state)); + hasher.Write((const unsigned char*)&rng_counter, sizeof(rng_counter)); + ++rng_counter; + hasher.Finalize(buf); + memcpy(rng_state, buf + 32, 32); + } + memory_cleanse(buf, 64); +} + void GetStrongRandBytes(unsigned char* out, int num) { assert(num <= 32); diff --git a/src/random.h b/src/random.h index 9551e1c461..6a63d57429 100644 --- a/src/random.h +++ b/src/random.h @@ -24,6 +24,13 @@ int GetRandInt(int nMax); uint256 GetRandHash(); /** + * Add a little bit of randomness to the output of GetStrongRangBytes. + * This sleeps for a millisecond, so should only be called when there is + * no other work to be done. + */ +void RandAddSeedSleep(); + +/** * Function to gather random data from multiple sources, failing whenever any * of those source fail to provide a result. */ diff --git a/src/scheduler.cpp b/src/scheduler.cpp index 0c1cfa2718..923ba2c231 100644 --- a/src/scheduler.cpp +++ b/src/scheduler.cpp @@ -4,6 +4,7 @@ #include "scheduler.h" +#include "random.h" #include "reverselock.h" #include <assert.h> @@ -39,6 +40,11 @@ void CScheduler::serviceQueue() // is called. while (!shouldStop()) { try { + if (!shouldStop() && taskQueue.empty()) { + reverse_lock<boost::unique_lock<boost::mutex> > rlock(lock); + // Use this chance to get a tiny bit more entropy + RandAddSeedSleep(); + } while (!shouldStop() && taskQueue.empty()) { // Wait until there is something to do. newTaskScheduled.wait(lock); |