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Implement test for merkle tree malleability in CPartialMerkleTree

This is a check that is mentioned in BIP 37, but never implemented in the
reference code. As Bitcoin Core so far never decodes partial merkle trees,
this is not a problem. But perhaps others use the code as a reference.
0.13
Pieter Wuille 10 years ago
parent
commit
012598880c
  1. 10
      src/merkleblock.cpp
  2. 11
      src/test/pmt_tests.cpp

10
src/merkleblock.cpp

@ -93,10 +93,16 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns
} else { } else {
// otherwise, descend into the subtrees to extract matched txids and hashes // otherwise, descend into the subtrees to extract matched txids and hashes
uint256 left = TraverseAndExtract(height-1, pos*2, nBitsUsed, nHashUsed, vMatch), right; uint256 left = TraverseAndExtract(height-1, pos*2, nBitsUsed, nHashUsed, vMatch), right;
if (pos*2+1 < CalcTreeWidth(height-1)) if (pos*2+1 < CalcTreeWidth(height-1)) {
right = TraverseAndExtract(height-1, pos*2+1, nBitsUsed, nHashUsed, vMatch); right = TraverseAndExtract(height-1, pos*2+1, nBitsUsed, nHashUsed, vMatch);
else if (right == left) {
// If the left and right branch should never be identical as the transaction
// hashes covered by them must be unique.
fBad = true;
}
} else {
right = left; right = left;
}
// and combine them before returning // and combine them before returning
return Hash(BEGIN(left), END(left), BEGIN(right), END(right)); return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
} }

11
src/test/pmt_tests.cpp

@ -10,6 +10,7 @@
#include <vector> #include <vector>
#include <boost/assign/list_of.hpp>
#include <boost/test/unit_test.hpp> #include <boost/test/unit_test.hpp>
using namespace std; using namespace std;
@ -104,4 +105,14 @@ BOOST_AUTO_TEST_CASE(pmt_test1)
} }
} }
BOOST_AUTO_TEST_CASE(pmt_malleability)
{
std::vector<uint256> vTxid = boost::assign::list_of(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(9)(10);
std::vector<bool> vMatch = boost::assign::list_of(false)(false)(false)(false)(false)(false)(false)(false)(false)(true)(true)(false);
CPartialMerkleTree tree(vTxid, vMatch);
std::vector<uint256> vTxid2;
BOOST_CHECK(tree.ExtractMatches(vTxid) == 0);
}
BOOST_AUTO_TEST_SUITE_END() BOOST_AUTO_TEST_SUITE_END()

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