Merge bitcoin#24213: refactor: use Span in random.*

3ae7791 refactor: use Span in random.* (pasta)

Pull request description:

  ~This PR does two things~
  1. use a Span<unsigned char> for GetRandBytes and GetStrongRandBytes

  ~2. make GetRand a template for which any integral type can be used, where the default behavior is to return a random integral up to the max of the integral unless a max is provided.
  This simplifies a lot of code from `GetRand(std::numeric_limits<uint64_t>::max()` -> `GetRand<uint64_t>()`~

  MarcoFalke this was inspired by your comment here: bitcoin#24185 (comment) about using Span, so hopefully I'll be able to get this PR done and merged 😂

  ~Also, if requested I could revert the `GetRand(std::numeric_limits<uint64_t>::max()` -> `GetRand<uint64_t>()` related changes if it ends up causing too many conflicts~

ACKs for top commit:
  laanwj:
    Thank you! Code review re-ACK 3ae7791

Tree-SHA512: 12375a83b68b288916ba0de81cfcab4aac14389a66a36811ae850427435eb67dd55e47df9ac3ec47db4e214f4330139e548bec815fff8a3f571484ea558dca79

Author: laanwj

src/addrdb.cpp

@@ -99,7 +99,7 @@ bool SerializeFileDB(const std::string& prefix, const fs::path& path, const Data
 {
     // Generate random temporary filename
     uint16_t randv = 0;
-    GetRandBytes((unsigned char*)&randv, sizeof(randv));
+    GetRandBytes({(unsigned char*)&randv, sizeof(randv)});
     std::string tmpfn = strprintf("%s.%04x", prefix, randv);
 
     // open temp output file, and associate with CAutoFile

src/bls/bls.cpp

@@ -63,7 +63,7 @@ void CBLSSecretKey::MakeNewKey()
 {
     unsigned char buf[SerSize];
     while (true) {
-        GetStrongRandBytes(buf, sizeof(buf));
+        GetStrongRandBytes({buf, sizeof(buf)});
         try {
             impl = bls::PrivateKey::FromBytes(bls::Bytes(reinterpret_cast<const uint8_t*>(buf), SerSize));
             break;

src/bls/bls_ies.cpp

@@ -97,7 +97,7 @@ void CBLSIESMultiRecipientBlobs::InitEncrypt(size_t count)
 {
     ephemeralSecretKey.MakeNewKey();
     ephemeralPubKey = ephemeralSecretKey.GetPublicKey();
-    GetStrongRandBytes(ivSeed.begin(), ivSeed.size());
+    GetStrongRandBytes({ivSeed.begin(), ivSeed.size()});
 
     uint256 iv = ivSeed;
     ivVector.resize(count);

src/dbwrapper.cpp

@@ -224,7 +224,7 @@ const unsigned int CDBWrapper::OBFUSCATE_KEY_NUM_BYTES = 8;
 std::vector<unsigned char> CDBWrapper::CreateObfuscateKey() const
 {
     std::vector<uint8_t> ret(OBFUSCATE_KEY_NUM_BYTES);
-    GetRandBytes(ret.data(), OBFUSCATE_KEY_NUM_BYTES);
+    GetRandBytes(ret);
     return ret;
 }
 

src/key.cpp

@@ -157,7 +157,7 @@ bool CKey::Check(const unsigned char *vch) {
 
 void CKey::MakeNewKey(bool fCompressedIn) {
     do {
-        GetStrongRandBytes(keydata.data(), keydata.size());
+        GetStrongRandBytes(keydata);
     } while (!Check(keydata.data()));
     fValid = true;
     fCompressed = fCompressedIn;
@@ -242,7 +242,7 @@ bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
     }
     unsigned char rnd[8];
     std::string str = "Bitcoin key verification\n";
-    GetRandBytes(rnd, sizeof(rnd));
+    GetRandBytes(rnd);
     uint256 hash;
     CHash256().Write(MakeUCharSpan(str)).Write(rnd).Finalize(hash);
     std::vector<unsigned char> vchSig;
@@ -406,7 +406,7 @@ void ECC_Start() {
     {
         // Pass in a random blinding seed to the secp256k1 context.
         std::vector<unsigned char, secure_allocator<unsigned char>> vseed(32);
-        GetRandBytes(vseed.data(), 32);
+        GetRandBytes(vseed);
         bool ret = secp256k1_context_randomize(ctx, vseed.data());
         assert(ret);
     }

src/net_processing.cpp

@@ -1247,7 +1247,7 @@ void PeerManagerImpl::PushNodeVersion(CNode& pnode, const Peer& peer)
     CAddress addrMe = CAddress(CService(), nLocalNodeServices);
 
     uint256 mnauthChallenge;
-    GetRandBytes(mnauthChallenge.begin(), mnauthChallenge.size());
+    GetRandBytes({mnauthChallenge.begin(), mnauthChallenge.size()});
     pnode.SetSentMNAuthChallenge(mnauthChallenge);
 
     int nProtocolVersion = PROTOCOL_VERSION;
@@ -5220,7 +5220,7 @@ void PeerManagerImpl::MaybeSendPing(CNode& node_to, Peer& peer, std::chrono::mic
     if (pingSend) {
         uint64_t nonce = 0;
         while (nonce == 0) {
-            GetRandBytes((unsigned char*)&nonce, sizeof(nonce));
+            GetRandBytes({(unsigned char*)&nonce, sizeof(nonce)});
         }
         peer.m_ping_queued = false;
         peer.m_ping_start = now;

src/random.cpp

@@ -17,6 +17,7 @@
 #include <logging.h>  // for LogPrintf()
 #include <randomenv.h>
 #include <support/allocators/secure.h>
+#include <span.h>
 #include <sync.h>     // for Mutex
 #include <util/time.h> // for GetTimeMicros()
 
@@ -582,8 +583,8 @@ static void ProcRand(unsigned char* out, int num, RNGLevel level) noexcept
     }
 }
 
-void GetRandBytes(unsigned char* buf, int num) noexcept { ProcRand(buf, num, RNGLevel::FAST); }
-void GetStrongRandBytes(unsigned char* buf, int num) noexcept { ProcRand(buf, num, RNGLevel::SLOW); }
+void GetRandBytes(Span<unsigned char> bytes) noexcept { ProcRand(bytes.data(), bytes.size(), RNGLevel::FAST); }
+void GetStrongRandBytes(Span<unsigned char> bytes) noexcept { ProcRand(bytes.data(), bytes.size(), RNGLevel::SLOW); }
 void RandAddPeriodic() noexcept { ProcRand(nullptr, 0, RNGLevel::PERIODIC); }
 void RandAddEvent(const uint32_t event_info) noexcept { GetRNGState().AddEvent(event_info); }
 
@@ -602,7 +603,7 @@ int GetRandInt(int nMax) noexcept
 uint256 GetRandHash() noexcept
 {
     uint256 hash;
-    GetRandBytes((unsigned char*)&hash, sizeof(hash));
+    GetRandBytes(hash);
     return hash;
 }
 

src/random.h

@@ -69,7 +69,7 @@
  *
  * Thread-safe.
  */
-void GetRandBytes(unsigned char* buf, int num) noexcept;
+void GetRandBytes(Span<unsigned char> bytes) noexcept;
 /** Generate a uniform random integer in the range [0..range). Precondition: range > 0 */
 uint64_t GetRand(uint64_t nMax) noexcept;
 /** Generate a uniform random duration in the range [0..max). Precondition: max.count() > 0 */
@@ -98,7 +98,7 @@ bool GetRandBool(double rate);
  *
  * Thread-safe.
  */
-void GetStrongRandBytes(unsigned char* buf, int num) noexcept;
+void GetStrongRandBytes(Span<unsigned char> bytes) noexcept;
 
 /**
  * Gather entropy from various expensive sources, and feed them to the PRNG state.

src/rpc/request.cpp

@@ -77,7 +77,7 @@ bool GenerateAuthCookie(std::string *cookie_out)
 {
     const size_t COOKIE_SIZE = 32;
     unsigned char rand_pwd[COOKIE_SIZE];
-    GetRandBytes(rand_pwd, COOKIE_SIZE);
+    GetRandBytes(rand_pwd);
     std::string cookie = COOKIEAUTH_USER + ":" + HexStr(rand_pwd);
 
     /** the umask determines what permissions are used to create this file -

src/test/key_tests.cpp

@@ -204,7 +204,7 @@ BOOST_AUTO_TEST_CASE(key_key_negation)
     // create a dummy hash for signature comparison
     unsigned char rnd[8];
     std::string str = "Bitcoin key verification\n";
-    GetRandBytes(rnd, sizeof(rnd));
+    GetRandBytes(rnd);
     uint256 hash;
     CHash256().Write(MakeUCharSpan(str)).Write(rnd).Finalize(hash);