Merge pull request dogecoin#3521 from xanimo/1.15.0-dev-next-random-p…

…re-14955

backport: random.h/.cpp cherry-picks

src/bench/bench_bitcoin.cpp

@@ -5,10 +5,12 @@
 #include "bench.h"  // for BenchRunner
 #include "key.h"    // for ECC_Start, ECC_Stop
 #include "util.h"   // for SetupEnvironment, fPrintToDebugLog
+#include "random.h"
 
 int
 main(int argc, char** argv)
 {
+    RandomInit();
     ECC_Start();
     SetupEnvironment();
     fPrintToDebugLog = false; // don't want to write to debug.log file

src/compat.h

@@ -75,6 +75,12 @@ typedef u_int SOCKET;
 #define MAX_PATH            1024
 #endif
 
+// ssize_t is POSIX, and not present when using MSVC.
+#ifdef _MSC_VER
+#include <BaseTsd.h>
+typedef SSIZE_T ssize_t;
+#endif
+
 // As Solaris does not have the MSG_NOSIGNAL flag for send(2) syscall, it is defined as 0
 #if !defined(HAVE_MSG_NOSIGNAL) && !defined(MSG_NOSIGNAL)
 #define MSG_NOSIGNAL 0

src/init.cpp

@@ -1188,6 +1188,7 @@ bool AppInitSanityChecks()
     // ********************************************************* Step 4: sanity checks
 
     // Initialize elliptic curve code
+    RandomInit();
     ECC_Start();
     globalVerifyHandle.reset(new ECCVerifyHandle());
 

src/random.cpp

@@ -16,6 +16,8 @@
 
 #include <stdlib.h>
 #include <limits>
+#include <chrono>
+#include <thread>
 
 #ifndef WIN32
 #include <sys/time.h>
@@ -35,6 +37,10 @@
 #include <sys/sysctl.h>
 #endif
 
+#if defined(__x86_64__) || defined(__amd64__) || defined(__i386__)
+#include <cpuid.h>
+#endif
+
 #include <openssl/err.h>
 #include <openssl/rand.h>
 
@@ -46,15 +52,77 @@ static void RandFailure()
 
 static inline int64_t GetPerformanceCounter()
 {
-    int64_t nCounter = 0;
-#ifdef WIN32
-    QueryPerformanceCounter((LARGE_INTEGER*)&nCounter);
+    // Read the hardware time stamp counter when available.
+    // See https://en.wikipedia.org/wiki/Time_Stamp_Counter for more information.
+#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
+    return __rdtsc();
+#elif !defined(_MSC_VER) && defined(__i386__)
+    uint64_t r = 0;
+    __asm__ volatile ("rdtsc" : "=A"(r)); // Constrain the r variable to the eax:edx pair.
+    return r;
+#elif !defined(_MSC_VER) && (defined(__x86_64__) || defined(__amd64__))
+    uint64_t r1 = 0, r2 = 0;
+    __asm__ volatile ("rdtsc" : "=a"(r1), "=d"(r2)); // Constrain r1 to rax and r2 to rdx.
+    return (r2 << 32) | r1;
+#else
+    // Fall back to using C++11 clock (usually microsecond or nanosecond precision)
+    return std::chrono::high_resolution_clock::now().time_since_epoch().count();
+#endif
+}
+
+
+#if defined(__x86_64__) || defined(__amd64__) || defined(__i386__)
+static std::atomic<bool> hwrand_initialized{false};
+static bool rdrand_supported = false;
+static constexpr uint32_t CPUID_F1_ECX_RDRAND = 0x40000000;
+static void RDRandInit()
+{
+    uint32_t eax, ebx, ecx, edx;
+    if (__get_cpuid(1, &eax, &ebx, &ecx, &edx) && (ecx & CPUID_F1_ECX_RDRAND)) {
+        LogPrintf("Using RdRand as an additional entropy source\n");
+        rdrand_supported = true;
+    }
+    hwrand_initialized.store(true);
+}
+#else
+static void RDRandInit() {}
+#endif
+
+static bool GetHWRand(unsigned char* ent32) {
+#if defined(__x86_64__) || defined(__amd64__) || defined(__i386__)
+    assert(hwrand_initialized.load(std::memory_order_relaxed));
+    if (rdrand_supported) {
+        uint8_t ok;
+        // Not all assemblers support the rdrand instruction, write it in hex.
+#ifdef __i386__
+        for (int iter = 0; iter < 4; ++iter) {
+            uint32_t r1, r2;
+            __asm__ volatile (".byte 0x0f, 0xc7, 0xf0;" // rdrand %eax
+                              ".byte 0x0f, 0xc7, 0xf2;" // rdrand %edx
+                              "setc %2" :
+                              "=a"(r1), "=d"(r2), "=q"(ok) :: "cc");
+            if (!ok) return false;
+            WriteLE32(ent32 + 8 * iter, r1);
+            WriteLE32(ent32 + 8 * iter + 4, r2);
+        }
 #else
-    timeval t;
-    gettimeofday(&t, NULL);
-    nCounter = (int64_t)(t.tv_sec * 1000000 + t.tv_usec);
+        uint64_t r1, r2, r3, r4;
+        __asm__ volatile (".byte 0x48, 0x0f, 0xc7, 0xf0, " // rdrand %rax
+                                "0x48, 0x0f, 0xc7, 0xf3, " // rdrand %rbx
+                                "0x48, 0x0f, 0xc7, 0xf1, " // rdrand %rcx
+                                "0x48, 0x0f, 0xc7, 0xf2; " // rdrand %rdx
+                          "setc %4" :
+                          "=a"(r1), "=b"(r2), "=c"(r3), "=d"(r4), "=q"(ok) :: "cc");
+        if (!ok) return false;
+        WriteLE64(ent32, r1);
+        WriteLE64(ent32 + 8, r2);
+        WriteLE64(ent32 + 16, r3);
+        WriteLE64(ent32 + 24, r4);
+#endif
+        return true;
+    }
 #endif
-    return nCounter;
+    return false;
 }
 
 void RandAddSeed()
@@ -119,6 +187,7 @@ void GetDevURandom(unsigned char *ent32)
     do {
         ssize_t n = read(f, ent32 + have, NUM_OS_RANDOM_BYTES - have);
         if (n <= 0 || n + have > NUM_OS_RANDOM_BYTES) {
+            close(f);
             RandFailure();
         }
         have += n;
@@ -219,6 +288,11 @@ void GetStrongRandBytes(unsigned char* out, int num)
     GetOSRand(buf);
     hasher.Write(buf, 32);
 
+    // Third source: HW RNG, if available.
+    if (GetHWRand(buf)) {
+        hasher.Write(buf, 32);
+    }
+
     // Produce output
     hasher.Finalize(buf);
     memcpy(out, buf, num);
@@ -286,6 +360,8 @@ FastRandomContext::FastRandomContext(const uint256& seed) : requires_seed(false)
 
 bool Random_SanityCheck()
 {
+    uint64_t start = GetPerformanceCounter();
+
     /* This does not measure the quality of randomness, but it does test that
      * OSRandom() overwrites all 32 bytes of the output given a maximum
      * number of tries.
@@ -312,7 +388,18 @@ bool Random_SanityCheck()
 
         tries += 1;
     } while (num_overwritten < NUM_OS_RANDOM_BYTES && tries < MAX_TRIES);
-    return (num_overwritten == NUM_OS_RANDOM_BYTES); /* If this failed, bailed out after too many tries */
+    if (num_overwritten != NUM_OS_RANDOM_BYTES) return false; /* If this failed, bailed out after too many tries */
+
+    // Check that GetPerformanceCounter increases at least during a GetOSRand() call + 1ms sleep.
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    uint64_t stop = GetPerformanceCounter();
+    if (stop == start) return false;
+
+    // We called GetPerformanceCounter. Use it as entropy.
+    RAND_add((const unsigned char*)&start, sizeof(start), 1);
+    RAND_add((const unsigned char*)&stop, sizeof(stop), 1);
+
+    return true;
 }
 
 FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDeterministic), bytebuf_size(0), bitbuf_size(0)
@@ -323,3 +410,8 @@ FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDete
     uint256 seed;
     rng.SetKey(seed.begin(), 32);
 }
+
+void RandomInit()
+{
+    RDRandInit();
+}

src/random.h

@@ -11,6 +11,7 @@
 #include "uint256.h"
 
 #include <stdint.h>
+#include <limits>
 
 /* Seed OpenSSL PRNG with additional entropy data */
 void RandAddSeed();
@@ -114,14 +115,20 @@ class FastRandomContext {
 
     /** Generate a random boolean. */
     bool randbool() { return randbits(1); }
+
+    // Compatibility with the C++11 UniformRandomBitGenerator concept
+    typedef uint64_t result_type;
+    static constexpr uint64_t min() { return 0; }
+    static constexpr uint64_t max() { return std::numeric_limits<uint64_t>::max(); }
+    inline uint64_t operator()() { return rand64(); }
 };
 
 /* Number of random bytes returned by GetOSRand.
  * When changing this constant make sure to change all call sites, and make
  * sure that the underlying OS APIs for all platforms support the number.
  * (many cap out at 256 bytes).
  */
-static const ssize_t NUM_OS_RANDOM_BYTES = 32;
+static const int NUM_OS_RANDOM_BYTES = 32;
 
 /** Get 32 bytes of system entropy. Do not use this in application code: use
  * GetStrongRandBytes instead.
@@ -133,4 +140,7 @@ void GetOSRand(unsigned char *ent32);
  */
 bool Random_SanityCheck();
 
+/** Initialize the RNG. */
+void RandomInit();
+
 #endif // BITCOIN_RANDOM_H

src/test/random_tests.cpp

@@ -8,6 +8,9 @@
 
 #include <boost/test/unit_test.hpp>
 
+#include <random>
+#include <algorithm>
+
 BOOST_FIXTURE_TEST_SUITE(random_tests, BasicTestingSetup)
 
 BOOST_AUTO_TEST_CASE(osrandom_tests)
@@ -57,4 +60,23 @@ BOOST_AUTO_TEST_CASE(fastrandom_randbits)
     }
 }
 
+/** Does-it-compile test for compatibility with standard C++11 RNG interface. */
+BOOST_AUTO_TEST_CASE(stdrandom_test)
+{
+    FastRandomContext ctx;
+    std::uniform_int_distribution<int> distribution(3, 9);
+    for (int i = 0; i < 100; ++i) {
+        int x = distribution(ctx);
+        BOOST_CHECK(x >= 3);
+        BOOST_CHECK(x <= 9);
+
+        std::vector<int> test{1,2,3,4,5,6,7,8,9,10};
+        std::shuffle(test.begin(), test.end(), ctx);
+        for (int j = 1; j <= 10; ++j) {
+            BOOST_CHECK(std::find(test.begin(), test.end(), j) != test.end());
+        }
+    }
+
+}
+
 BOOST_AUTO_TEST_SUITE_END()

src/test/test_bitcoin.cpp

@@ -43,6 +43,7 @@ static const int COINBASE_MATURITY = 60*4; // 4 hours of blocks
 
 BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
 {
+        RandomInit();
         ECC_Start();
         SetupEnvironment();
         SetupNetworking();