draft of merkle tree

keep-starknet-strange · Aug 7, 2024 · 2854670 · 2854670
1 parent 6aa388b
commit 2854670
Showing 1 changed file with 8 additions and 3 deletions.
diff --git a/src/merkle_tree.cairo b/src/merkle_tree.cairo
@@ -1,13 +1,18 @@
 use super::utils::double_sha256;
 
 pub fn merkle_root(ref txids: Array<u256>) -> u256 {
-    if txids.len() % 2 == 1 {
-        txids.append(*txids.at(txids.len() - 1));
+    let len = txids.len();
+    if len % 2 == 1 {
+        txids.append(*txids.at(len - 1));
+    } else {
+        // CVE-2012-2459 bug fix
+        assert!(
+            txids.at(len - 1) != txids.at(len - 2), "unexpected node duplication in merkle tree"
+        );
     }
 
     let mut next_txids = ArrayTrait::new();
     let mut i = 0;
-    let len = txids.len();
     while i < len {
         next_txids.append(double_sha256(*txids.at(i), *txids.at(i + 1)));
         i += 2;