Fix potential null dereferences

src/net_processing.cpp

@@ -232,7 +232,7 @@ CNodeState* State(NodeId pnode)
 {
     std::map<NodeId, CNodeState>::iterator it = mapNodeState.find(pnode);
     if (it == mapNodeState.end())
-        return NULL;
+        return nullptr;
     return &it->second;
 }
 
@@ -272,6 +272,7 @@ void MarkBlockAsReceived(const uint256& hash)
     std::map<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash);
     if (itInFlight != mapBlocksInFlight.end()) {
         CNodeState* state = State(itInFlight->second.first);
+        assert(state != nullptr);
         nQueuedValidatedHeaders -= itInFlight->second.second->fValidatedHeaders;
         state->vBlocksInFlight.erase(itInFlight->second.second);
         state->nBlocksInFlight--;
@@ -284,7 +285,7 @@ void MarkBlockAsReceived(const uint256& hash)
 void MarkBlockAsInFlight(NodeId nodeid, const uint256& hash, const CBlockIndex* pindex = nullptr)
 {
     CNodeState* state = State(nodeid);
-    assert(state != NULL);
+    assert(state != nullptr);
 
     // Make sure it's not listed somewhere already.
     MarkBlockAsReceived(hash);
@@ -300,7 +301,7 @@ void MarkBlockAsInFlight(NodeId nodeid, const uint256& hash, const CBlockIndex*
 void ProcessBlockAvailability(NodeId nodeid)
 {
     CNodeState* state = State(nodeid);
-    assert(state != NULL);
+    assert(state != nullptr);
 
     if (!state->hashLastUnknownBlock.IsNull()) {
         BlockMap::iterator itOld = mapBlockIndex.find(state->hashLastUnknownBlock);
@@ -316,7 +317,7 @@ void ProcessBlockAvailability(NodeId nodeid)
 void UpdateBlockAvailability(NodeId nodeid, const uint256& hash)
 {
     CNodeState* state = State(nodeid);
-    assert(state != NULL);
+    assert(state != nullptr);
 
     ProcessBlockAvailability(nodeid);
 
@@ -340,7 +341,7 @@ void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vector<con
 
     vBlocks.reserve(vBlocks.size() + count);
     CNodeState* state = State(nodeid);
-    assert(state != NULL);
+    assert(state != nullptr);
 
     // Make sure pindexBestKnownBlock is up to date, we'll need it.
     ProcessBlockAvailability(nodeid);

src/rpc/blockchain.cpp

@@ -727,6 +727,7 @@ static void ApplyStats(CCoinsStats &stats, CHashWriter& ss, const uint256& hash,
 static bool GetUTXOStats(CCoinsView *view, CCoinsStats &stats)
 {
     std::unique_ptr<CCoinsViewCursor> pcursor(view->Cursor());
+    assert(pcursor);
 
     CHashWriter ss(SER_GETHASH, PROTOCOL_VERSION);
     stats.hashBlock = pcursor->GetBestBlock();
@@ -864,6 +865,7 @@ UniValue gettxout(const JSONRPCRequest& request)
 
     BlockMap::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
     CBlockIndex* pindex = it->second;
+    assert(pindex != nullptr);
     ret.pushKV("bestblock", pindex->GetBlockHash().GetHex());
     if (coin.nHeight == MEMPOOL_HEIGHT) {
         ret.pushKV("confirmations", 0);

src/validation.cpp

@@ -1870,6 +1870,7 @@ void static UpdateTip(CBlockIndex* pindexNew)
     }
 
     const CBlockIndex* pChainTip = chainActive.Tip();
+    assert(pChainTip != nullptr);
     LogPrintf("%s: new best=%s  height=%d version=%d  log2_work=%.16f  tx=%lu  date=%s progress=%f  cache=%.1fMiB(%utxo)  evodb_cache=%.1fMiB\n",
               __func__,
               pChainTip->GetBlockHash().GetHex(), pChainTip->nHeight, pChainTip->nVersion, log(pChainTip->nChainWork.getdouble()) / log(2.0), (unsigned long)pChainTip->nChainTx,