From a9b6ba0b7cd27a64307987afaab7f60bf9b4a15b Mon Sep 17 00:00:00 2001
From: practicalswift <practicalswift@users.noreply.github.com>
Date: Mon, 6 Nov 2017 23:20:43 +0100
Subject: [PATCH] Add missing cs_main locks when calling
 blockToJSON/blockheaderToJSON

---
 src/rest.cpp           | 13 ++++++++++---
 src/rpc/blockchain.cpp |  2 ++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/rest.cpp b/src/rest.cpp
index 4d2cdfdf08..b1fc96bdf5 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -178,8 +178,11 @@ static bool rest_headers(HTTPRequest* req,
     }
     case RF_JSON: {
         UniValue jsonHeaders(UniValue::VARR);
-        for (const CBlockIndex *pindex : headers) {
-            jsonHeaders.push_back(blockheaderToJSON(pindex));
+        {
+            LOCK(cs_main);
+            for (const CBlockIndex *pindex : headers) {
+                jsonHeaders.push_back(blockheaderToJSON(pindex));
+            }
         }
         std::string strJSON = jsonHeaders.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
@@ -239,7 +242,11 @@ static bool rest_block(HTTPRequest* req,
     }
 
     case RF_JSON: {
-        UniValue objBlock = blockToJSON(block, pblockindex, showTxDetails);
+        UniValue objBlock;
+        {
+            LOCK(cs_main);
+            objBlock = blockToJSON(block, pblockindex, showTxDetails);
+        }
         std::string strJSON = objBlock.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
         req->WriteReply(HTTP_OK, strJSON);
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 68af376f35..8d01d8ba9c 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -78,6 +78,7 @@ double GetDifficulty(const CBlockIndex* blockindex)
 
 UniValue blockheaderToJSON(const CBlockIndex* blockindex)
 {
+    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.push_back(Pair("hash", blockindex->GetBlockHash().GetHex()));
     int confirmations = -1;
@@ -106,6 +107,7 @@ UniValue blockheaderToJSON(const CBlockIndex* blockindex)
 
 UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails)
 {
+    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.push_back(Pair("hash", blockindex->GetBlockHash().GetHex()));
     int confirmations = -1;