9102: Really don't validate genesis block

Author: instagibbs

src/txdb.cpp

@@ -274,9 +274,11 @@ bool CBlockTreeDB::LoadBlockIndexGuts(const Consensus::Params& consensusParams,
                 pindexNew->nStatus        = diskindex.nStatus;
                 pindexNew->nTx            = diskindex.nTx;
 
-                if (!CheckProofOfWork(pindexNew->GetBlockHash(), pindexNew->nBits, consensusParams))
-                    return error("%s: CheckProofOfWork failed: %s", __func__, pindexNew->ToString());
-
+                const uint256 block_hash = pindexNew->GetBlockHash();
+                if (!CheckProofOfWork(block_hash, pindexNew->nBits, consensusParams) &&
+                    block_hash != consensusParams.hashGenesisBlock) {
+                    return error("%s: CheckProofOfWork: %s, %s", __func__, block_hash.ToString(), pindexNew->ToString());
+                }
                 pcursor->Next();
             } else {
                 return error("%s: failed to read value", __func__);

src/validation.cpp

@@ -1091,8 +1091,11 @@ bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus:
     }
 
     // Check the header
-    if (!CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
+    const uint256 block_hash = block.GetHash();
+    if (!CheckProofOfWork(block_hash, block.nBits, consensusParams) &&
+        block_hash != consensusParams.hashGenesisBlock) {
         return error("ReadBlockFromDisk: Errors in block header at %s", pos.ToString());
+    }
 
     return true;
 }
@@ -1810,6 +1813,18 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl
     assert(*pindex->phashBlock == block.GetHash());
     int64_t nTimeStart = GetTimeMicros();
 
+    // verify that the view's current state corresponds to the previous block
+    const uint256 hashPrevBlock = pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash();
+    assert(hashPrevBlock == view.GetBestBlock());
+
+    // Special case for the genesis block, skipping connection of its transactions
+    // (its coinbase is unspendable)
+    if (block.GetHash() == chainparams.GetConsensus().hashGenesisBlock) {
+        if (!fJustCheck)
+            view.SetBestBlock(pindex->GetBlockHash());
+        return true;
+    }
+
     // Check it again in case a previous version let a bad block in
     // NOTE: We don't currently (re-)invoke ContextualCheckBlock() or
     // ContextualCheckBlockHeader() here. This means that if we add a new
@@ -1833,18 +1848,6 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl
         return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state));
     }
 
-    // verify that the view's current state corresponds to the previous block
-    uint256 hashPrevBlock = pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash();
-    assert(hashPrevBlock == view.GetBestBlock());
-
-    // Special case for the genesis block, skipping connection of its transactions
-    // (its coinbase is unspendable)
-    if (block.GetHash() == chainparams.GetConsensus().hashGenesisBlock) {
-        if (!fJustCheck)
-            view.SetBestBlock(pindex->GetBlockHash());
-        return true;
-    }
-
     nBlocksTotal++;
 
     bool fScriptChecks = true;
@@ -3498,8 +3501,9 @@ bool CChainState::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CVali
         if (pindex->nChainWork < nMinimumChainWork) return true;
     }
 
-    if (!CheckBlock(block, state, chainparams.GetConsensus()) ||
-        !ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindex->pprev)) {
+    if (chainparams.GetConsensus().hashGenesisBlock != block.GetHash() &&
+        (!CheckBlock(block, state, chainparams.GetConsensus()) ||
+         !ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindex->pprev))) {
         if (state.IsInvalid() && !state.CorruptionPossible()) {
             pindex->nStatus |= BLOCK_FAILED_VALID;
             setDirtyBlockIndex.insert(pindex);