Merge #17577: refactor: deduplicate the message sign/verify code

e193a84fb28068e38d5f54fbfd6208428c5bb655 Refactor message hashing into a utility function (Jeffrey Czyz)
f8f0d9893d7969bdaa870fadb94ec5d0dfa8334d Deduplicate the message signing code (Vasil Dimov)
2ce3447eb1e25ec7aec4b300dabf6c1e394f1906 Deduplicate the message verifying code (Vasil Dimov)

Pull request description:

  The message signing and verifying logic was replicated in a few places
  in the code. Consolidate in a newly introduced `MessageSign()` and
  `MessageVerify()` and add unit tests for them.

ACKs for top commit:
  Sjors:
    re-ACK e193a84fb28068e38d5f54fbfd6208428c5bb655
  achow101:
    ACK e193a84fb28068e38d5f54fbfd6208428c5bb655
  instagibbs:
    utACK https://github.com/bitcoin/bitcoin/pull/17577/commits/e193a84fb28068e38d5f54fbfd6208428c5bb655
  meshcollider:
    utACK e193a84fb28068e38d5f54fbfd6208428c5bb655

Tree-SHA512: b0e02a7d4623a98c8f8c77627af1725e6df07700de4630c2f75da6beacdf55414c38ba147bc6d2a757491ab07c827dddf93e8632fe600478760e255714ddab88

1 files changed, 15 insertions, 27 deletions

diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index c8711f44d4..4279756f4d 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -13,9 +13,9 @@
 #include <scheduler.h>
 #include <script/descriptor.h>
 #include <util/check.h>
+#include <util/message.h> // For MessageSign(), MessageVerify()
 #include <util/strencodings.h>
 #include <util/system.h>
-#include <util/validation.h>
 
 #include <stdint.h>
 #include <tuple>
@@ -278,31 +278,21 @@ static UniValue verifymessage(const JSONRPCRequest& request)
     std::string strSign     = request.params[1].get_str();
     std::string strMessage  = request.params[2].get_str();
 
-    CTxDestination destination = DecodeDestination(strAddress);
-    if (!IsValidDestination(destination)) {
+    switch (MessageVerify(strAddress, strSign, strMessage)) {
+    case MessageVerificationResult::ERR_INVALID_ADDRESS:
         throw JSONRPCError(RPC_TYPE_ERROR, "Invalid address");
-    }
-
-    const PKHash *pkhash = boost::get<PKHash>(&destination);
-    if (!pkhash) {
+    case MessageVerificationResult::ERR_ADDRESS_NO_KEY:
         throw JSONRPCError(RPC_TYPE_ERROR, "Address does not refer to key");
-    }
-
-    bool fInvalid = false;
-    std::vector<unsigned char> vchSig = DecodeBase64(strSign.c_str(), &fInvalid);
-
-    if (fInvalid)
+    case MessageVerificationResult::ERR_MALFORMED_SIGNATURE:
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Malformed base64 encoding");
-
-    CHashWriter ss(SER_GETHASH, 0);
-    ss << strMessageMagic;
-    ss << strMessage;
-
-    CPubKey pubkey;
-    if (!pubkey.RecoverCompact(ss.GetHash(), vchSig))
+    case MessageVerificationResult::ERR_PUBKEY_NOT_RECOVERED:
+    case MessageVerificationResult::ERR_NOT_SIGNED:
         return false;
+    case MessageVerificationResult::OK:
+        return true;
+    }
 
-    return (pubkey.GetID() == *pkhash);
+    return false;
 }
 
 static UniValue signmessagewithprivkey(const JSONRPCRequest& request)
@@ -334,15 +324,13 @@ static UniValue signmessagewithprivkey(const JSONRPCRequest& request)
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid private key");
     }
 
-    CHashWriter ss(SER_GETHASH, 0);
-    ss << strMessageMagic;
-    ss << strMessage;
+    std::string signature;
 
-    std::vector<unsigned char> vchSig;
-    if (!key.SignCompact(ss.GetHash(), vchSig))
+    if (!MessageSign(key, strMessage, signature)) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Sign failed");
+    }
 
-    return EncodeBase64(vchSig.data(), vchSig.size());
+    return signature;
 }
 
 static UniValue setmocktime(const JSONRPCRequest& request)