consensus: from v12, enforce >= 2 outputs

3 files changed, 15 insertions, 0 deletions

diff --git a/src/cryptonote_basic/verification_context.h b/src/cryptonote_basic/verification_context.h
index 36b63f254..3d7200fae 100644
--- a/src/cryptonote_basic/verification_context.h
+++ b/src/cryptonote_basic/verification_context.h
@@ -48,6 +48,7 @@ namespace cryptonote
     bool m_overspend;
     bool m_fee_too_low;
     bool m_not_rct;
+    bool m_too_few_outputs;
   };
 
   struct block_verification_context
diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index 56b6a63b7..fc718c4f7 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -147,6 +147,7 @@
 #define HF_VERSION_PER_BYTE_FEE                 8
 #define HF_VERSION_SMALLER_BP                   10
 #define HF_VERSION_LONG_TERM_BLOCK_WEIGHT       10
+#define HF_VERSION_MIN_2_OUTPUTS                12
 
 #define PER_KB_FEE_QUANTIZATION_DECIMALS        8
 
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index f733efb2f..e2cf9a703 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -2800,6 +2800,19 @@ bool Blockchain::check_tx_inputs(transaction& tx, tx_verification_context &tvc,
 
   const uint8_t hf_version = m_hardfork->get_current_version();
 
+  if (hf_version >= HF_VERSION_MIN_2_OUTPUTS)
+  {
+    if (tx.version >= 2)
+    {
+      if (tx.vout.size() < 2)
+      {
+        MERROR_VER("Tx " << get_transaction_hash(tx) << " has fewer than two outputs");
+        tvc.m_too_few_outputs = true;
+        return false;
+      }
+    }
+  }
+
   // from hard fork 2, we require mixin at least 2 unless one output cannot mix with 2 others
   // if one output cannot mix with 2 others, we accept at most 1 output that can mix
   if (hf_version >= 2)