Merge bitcoin/bitcoin#27755: [24.x] rpc: Fix invalid bech32 handling

c2e9214effe9abecae6f81cb10158f9661065da3 rpc: Fix invalid bech32 handling (MarcoFalke)

Pull request description:

  Backports https://github.com/bitcoin/bitcoin/pull/27727 to 24.x. Not a clean cherry-pick.

ACKs for top commit:
  achow101:
    ACK c2e9214effe9abecae6f81cb10158f9661065da3
  stickies-v:
    ACK c2e9214effe9abecae6f81cb10158f9661065da3

Tree-SHA512: 8fd5b4c0016e9f30061e327b5f75320e4ed27b1a7b61eafabefe87d351ab13c970e969ea85b2f4cab44c1b0f28214ee7c5b85e3e0549345b57f1fa724e3c814c

1 files changed, 12 insertions, 5 deletions

diff --git a/src/key_io.cpp b/src/key_io.cpp
index 6dd6f82112..d77829e046 100644
--- a/src/key_io.cpp
+++ b/src/key_io.cpp
@@ -109,13 +109,13 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
                 std::equal(pubkey_prefix.begin(), pubkey_prefix.end(), data.begin()))) {
             error_str = "Invalid length for Base58 address";
         } else {
-            error_str = "Invalid prefix for Base58-encoded address";
+            error_str = "Invalid or unsupported Base58-encoded address.";
         }
         return CNoDestination();
     } else if (!is_bech32) {
         // Try Base58 decoding without the checksum, using a much larger max length
         if (!DecodeBase58(str, data, 100)) {
-            error_str = "Not a valid Bech32 or Base58 encoding";
+            error_str = "Invalid or unsupported Segwit (Bech32) or Base58 encoding.";
         } else {
             error_str = "Invalid checksum or length of Base58 address";
         }
@@ -124,7 +124,11 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
 
     data.clear();
     const auto dec = bech32::Decode(str);
-    if ((dec.encoding == bech32::Encoding::BECH32 || dec.encoding == bech32::Encoding::BECH32M) && dec.data.size() > 0) {
+    if (dec.encoding == bech32::Encoding::BECH32 || dec.encoding == bech32::Encoding::BECH32M) {
+        if (dec.data.empty()) {
+            error_str = "Empty Bech32 data section";
+            return CNoDestination();
+        }
         // Bech32 decoding
         if (dec.hrp != params.Bech32HRP()) {
             error_str = "Invalid prefix for Bech32 address";
@@ -158,7 +162,7 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
                     }
                 }
 
-                error_str = "Invalid Bech32 v0 address data size";
+                error_str = strprintf("Invalid Bech32 v0 address program size (%s byte), per BIP141", data.size());
                 return CNoDestination();
             }
 
@@ -175,7 +179,7 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
             }
 
             if (data.size() < 2 || data.size() > BECH32_WITNESS_PROG_MAX_LEN) {
-                error_str = "Invalid Bech32 address data size";
+                error_str = strprintf("Invalid Bech32 address program size (%s byte)", data.size());
                 return CNoDestination();
             }
 
@@ -184,6 +188,9 @@ CTxDestination DecodeDestination(const std::string& str, const CChainParams& par
             std::copy(data.begin(), data.end(), unk.program);
             unk.length = data.size();
             return unk;
+        } else {
+            error_str = strprintf("Invalid padding in Bech32 data section");
+            return CNoDestination();
         }
     }