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Implement test for merkle tree malleability in CPartialMerkleTree

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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.
This commit is contained in:
Pieter Wuille 2014-11-22 15:44:43 +01:00
parent 3bb29a3e13
commit 012598880c
2 changed files with 19 additions and 2 deletions
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10
src/merkleblock.cpp
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@ -93,10 +93,16 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns
} else {
// otherwise, descend into the subtrees to extract matched txids and hashes
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);
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;
}
// and combine them before returning
return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
}

11
src/test/pmt_tests.cpp
View file

@ -10,6 +10,7 @@
#include <vector>
#include <boost/assign/list_of.hpp>
#include <boost/test/unit_test.hpp>
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()