Consistently use ParseHashV to validate hash inputs in rpc

ParseHashV validates the length and encoding of the string and throws
an informative RPC error on failure, which is as good or better than
these alternative calls.

Note I switched ParseHashV to check string length first, because
IsHex tests that the length is even, and an error like:
"must be of length 64 (not 63, for X)" is much more informative than
"must be hexadecimal string (not X)"

1 files changed, 9 insertions, 16 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index f70d506e13..b809fd0f5d 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -252,7 +252,7 @@ static UniValue waitforblock(const JSONRPCRequest& request)
         );
     int timeout = 0;
 
-    uint256 hash = uint256S(request.params[0].get_str());
+    uint256 hash(ParseHashV(request.params[0], "blockhash"));
 
     if (!request.params[1].isNull())
         timeout = request.params[1].get_int();
@@ -706,8 +706,7 @@ static UniValue getblockheader(const JSONRPCRequest& request)
 
     LOCK(cs_main);
 
-    std::string strHash = request.params[0].get_str();
-    uint256 hash(uint256S(strHash));
+    uint256 hash(ParseHashV(request.params[0], "hash"));
 
     bool fVerbose = true;
     if (!request.params[1].isNull())
@@ -800,8 +799,7 @@ static UniValue getblock(const JSONRPCRequest& request)
 
     LOCK(cs_main);
 
-    std::string strHash = request.params[0].get_str();
-    uint256 hash(uint256S(strHash));
+    uint256 hash(ParseHashV(request.params[0], "blockhash"));
 
     int verbosity = 1;
     if (!request.params[1].isNull()) {
@@ -1033,8 +1031,7 @@ UniValue gettxout(const JSONRPCRequest& request)
 
     UniValue ret(UniValue::VOBJ);
 
-    std::string strHash = request.params[0].get_str();
-    uint256 hash(uint256S(strHash));
+    uint256 hash(ParseHashV(request.params[0], "txid"));
     int n = request.params[1].get_int();
     COutPoint out(hash, n);
     bool fMempool = true;
@@ -1442,8 +1439,7 @@ static UniValue preciousblock(const JSONRPCRequest& request)
             + HelpExampleRpc("preciousblock", "\"blockhash\"")
         );
 
-    std::string strHash = request.params[0].get_str();
-    uint256 hash(uint256S(strHash));
+    uint256 hash(ParseHashV(request.params[0], "blockhash"));
     CBlockIndex* pblockindex;
 
     {
@@ -1478,8 +1474,7 @@ static UniValue invalidateblock(const JSONRPCRequest& request)
             + HelpExampleRpc("invalidateblock", "\"blockhash\"")
         );
 
-    std::string strHash = request.params[0].get_str();
-    uint256 hash(uint256S(strHash));
+    uint256 hash(ParseHashV(request.params[0], "blockhash"));
     CValidationState state;
 
     {
@@ -1518,8 +1513,7 @@ static UniValue reconsiderblock(const JSONRPCRequest& request)
             + HelpExampleRpc("reconsiderblock", "\"blockhash\"")
         );
 
-    std::string strHash = request.params[0].get_str();
-    uint256 hash(uint256S(strHash));
+    uint256 hash(ParseHashV(request.params[0], "blockhash"));
 
     {
         LOCK(cs_main);
@@ -1572,7 +1566,7 @@ static UniValue getchaintxstats(const JSONRPCRequest& request)
         LOCK(cs_main);
         pindex = chainActive.Tip();
     } else {
-        uint256 hash = uint256S(request.params[1].get_str());
+        uint256 hash(ParseHashV(request.params[1], "blockhash"));
         LOCK(cs_main);
         pindex = LookupBlockIndex(hash);
         if (!pindex) {
@@ -1711,8 +1705,7 @@ static UniValue getblockstats(const JSONRPCRequest& request)
 
         pindex = chainActive[height];
     } else {
-        const std::string strHash = request.params[0].get_str();
-        const uint256 hash(uint256S(strHash));
+        const uint256 hash(ParseHashV(request.params[0], "hash_or_height"));
         pindex = LookupBlockIndex(hash);
         if (!pindex) {
             throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");