From d8926263b78f1563f0698cd228a7d38fa9580bd2 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

zcash: cherry picked from commit a9b6ba0b7cd27a64307987afaab7f60bf9b4a15b
zcash: https://github.com/bitcoin/bitcoin/pull/11618
---
 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 225fec52f..0853665ea 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -173,8 +173,11 @@ 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));
+            }
         }
         string strJSON = jsonHeaders.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
@@ -238,7 +241,11 @@ 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);
+        }
         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 e4ba5ca84..5930b7a7e 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -103,6 +103,7 @@ static UniValue ValuePoolDesc(
 
 UniValue blockheaderToJSON(const CBlockIndex* blockindex)
 {
+    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
     int confirmations = -1;
@@ -220,6 +221,7 @@ UniValue blockToDeltasJSON(const CBlock& block, const CBlockIndex* blockindex)
 
 UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails = false)
 {
+    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", block.GetHash().GetHex());
     int confirmations = -1;