bip360: throw error when leaf version is non-standard ( 192 / c0 )

Author: jbride

bip-0360/ref-impl/common/tests/data/p2mr_construction.json

@@ -57,7 +57,7 @@
         },
         {
             "id": "p2mr_different_version_leaves",
-            "objective": "Tests P2MR with two script leaves of different versions.  TO-DO:  currently ignores given leaf version and over-rides.  Probably better to throw error",
+            "objective": "Tests P2MR with two script leaves of different versions.  BIP-360 requires all leaves to use leaf version 0xc0; a non-standard version must throw an error.",
             "given": {
                 "scriptTree": [
                     {
@@ -75,20 +75,8 @@
                     }
                 ]
             },
-            "intermediary": {
-                "leafHashes": [
-                    "8ad69ec7cf41c2a4001fd1f738bf1e505ce2277acdcaa63fe4765192497f47a7",
-                    "f224a923cd0021ab202ab139cc56802ddb92dcfc172b9212261a539df79a112a"
-                ],
-                "merkleRoot": "6c2dc106ab816b73f9d07e3cd1ef2c8c1256f519748e0813e4edd2405d277bef"
-            },
             "expected": {
-                "scriptPubKey": "52206c2dc106ab816b73f9d07e3cd1ef2c8c1256f519748e0813e4edd2405d277bef",
-                "bip350Address": "bc1zdskuzp4ts94h87ws0c7drmev3sf9dagewj8qsylyahfyqhf800hsam4d6e",
-                "scriptPathControlBlocks": [
-                    "c1f224a923cd0021ab202ab139cc56802ddb92dcfc172b9212261a539df79a112a",
-                    "c18ad69ec7cf41c2a4001fd1f738bf1e505ce2277acdcaa63fe4765192497f47a7"
-                ]
+                "error": "BIP-360 requires leaf version 0xc0; leaf 1 has version 250"
             }
         },
         {

bip-0360/ref-impl/rust/src/data_structures.rs

@@ -111,6 +111,7 @@ pub struct TestVector {
     pub id: String,
     pub objective: String,
     pub given: TestVectorGiven,
+    #[serde(default)]
     pub intermediary: TestVectorIntermediary,
     pub expected: TestVectorExpected,
 }
@@ -132,7 +133,7 @@ pub struct TestVectorGiven {
     pub control_block: Option<String>,
 }
 
-#[derive(Debug, Serialize, Deserialize, Clone)]
+#[derive(Debug, Default, Serialize, Deserialize, Clone)]
 pub struct TestVectorIntermediary {
 
     #[serde(default)]

bip-0360/ref-impl/rust/src/error.rs

@@ -13,4 +13,7 @@ pub enum P2MRError {
     // We can add more specific error variants here as needed
     #[error("Invalid script tree structure: {0}")]
     InvalidScriptTree(String),
+
+    #[error("BIP-360 requires leaf version 0xc0; leaf {0} has version {1}")]
+    InvalidLeafVersion(u8, u8),
 } 

bip-0360/ref-impl/rust/tests/p2mr_construction.rs

@@ -1,7 +1,7 @@
 use std::collections::HashSet;
 use bitcoin::{Network, ScriptBuf};
 use bitcoin::taproot::{LeafVersion, TapTree, ScriptLeaves, TapLeafHash, TaprootMerkleBranch, TapNodeHash};
-use bitcoin::p2mr::{P2mrBuilder, P2mrControlBlock, P2mrSpendInfo};
+use bitcoin::p2mr::{P2mrBuilder, P2mrControlBlock, P2mrSpendInfo, P2MR_LEAF_VERSION};
 use bitcoin::hashes::Hash;
 
 use hex;
@@ -72,7 +72,9 @@ fn test_p2mr_different_version_leaves() {
 
     let test_vectors = &*TEST_VECTORS;
     let test_vector = test_vectors.test_vector_map.get(P2MR_DIFFERENT_VERSION_LEAVES_TEST).unwrap();
-    process_test_vector_p2mr(test_vector).unwrap();
+    let test_result = process_test_vector_p2mr(test_vector);
+    assert!(matches!(test_result.unwrap_err().downcast_ref::<P2MRError>(),
+        Some(P2MRError::InvalidLeafVersion(_, _))));
 }
 
 #[test]
@@ -137,29 +139,37 @@ fn process_test_vector_p2mr(test_vector: &TestVector) -> anyhow::Result<()> {
     let mut p2mr_builder: P2mrBuilder = P2mrBuilder::new();
 
     let mut control_block_data: Vec<(ScriptBuf, LeafVersion)> = Vec::new();
+    let mut traversal_result: anyhow::Result<()> = Ok(());
 
     // 1)  traverse test vector script tree and add leaves to P2MR builder
     if let Some(script_tree) = tv_script_tree {
 
         script_tree.traverse_with_right_subtree_first(0, Direction::Root,&mut |node, depth, direction| {
 
+            if traversal_result.is_err() { return; }
+
             if let TVScriptTree::Leaf(tv_leaf) = node {
-                
+
                 let tv_leaf_script_bytes = hex::decode(&tv_leaf.script).unwrap();
-    
+
                 // NOTE:  IOT to execute script_info.control_block(..), will add these to a vector
                 let tv_leaf_script_buf = ScriptBuf::from_bytes(tv_leaf_script_bytes.clone());
                 let tv_leaf_version = LeafVersion::from_consensus(tv_leaf.leaf_version).unwrap();
+
+                if tv_leaf.leaf_version != P2MR_LEAF_VERSION {
+                    traversal_result = Err(P2MRError::InvalidLeafVersion(tv_leaf.id, tv_leaf.leaf_version).into());
+                    return;
+                }
+
                 control_block_data.push((tv_leaf_script_buf.clone(), tv_leaf_version));
-                
+
                 let mut modified_depth = depth + 1;
                 if direction == Direction::Root {
                     modified_depth = depth;
                 }
-                debug!("traverse_with_depth: leaf_count: {}, depth: {}, modified_depth: {}, direction: {}, tv_leaf_script: {}", 
+                debug!("traverse_with_depth: leaf_count: {}, depth: {}, modified_depth: {}, direction: {}, tv_leaf_script: {}",
                     tv_leaf_count, depth, modified_depth, direction, tv_leaf.script);
-                
-                // NOTE: Some of the the test vectors in this project specify leaves with non-standard versions (ie: 250 / 0xfa)
+
                 p2mr_builder = p2mr_builder.clone().add_leaf_with_ver(depth, tv_leaf_script_buf.clone(), tv_leaf_version)
                     .unwrap_or_else(|e| {
                         panic!("Failed to add leaf: {:?}", e);
@@ -177,6 +187,8 @@ fn process_test_vector_p2mr(test_vector: &TestVector) -> anyhow::Result<()> {
         return Err(P2MRError::MissingScriptTreeLeaf.into());
     }
 
+    traversal_result?;
+
     let spend_info: P2mrSpendInfo = p2mr_builder.clone()
         .finalize()
         .unwrap_or_else(|e| {