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Maintain state across GetStrongRandBytes calls

tags/v0.15.1
Pieter Wuille 4 years ago
parent
commit
97477c537e
1 changed files with 16 additions and 1 deletions
  1. 16
    1
      src/random.cpp

+ 16
- 1
src/random.cpp View File

@@ -32,6 +32,8 @@
#include <sys/sysctl.h>
#endif

#include <mutex>

#include <openssl/err.h>
#include <openssl/rand.h>

@@ -192,6 +194,10 @@ void GetRandBytes(unsigned char* buf, int num)
}
}

static std::mutex cs_rng_state;
static unsigned char rng_state[32] = {0};
static uint64_t rng_counter = 0;

void GetStrongRandBytes(unsigned char* out, int num)
{
assert(num <= 32);
@@ -207,8 +213,17 @@ void GetStrongRandBytes(unsigned char* out, int num)
GetOSRand(buf);
hasher.Write(buf, 32);

// Combine with and update state
{
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);
}

// Produce output
hasher.Finalize(buf);
memcpy(out, buf, num);
memory_cleanse(buf, 64);
}

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