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- // Copyright 2013 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include "net/cert/ct_log_verifier.h"
- #include <stdint.h>
- #include <memory>
- #include <string>
- #include <vector>
- #include "base/strings/string_number_conversions.h"
- #include "base/time/time.h"
- #include "crypto/secure_hash.h"
- #include "net/base/hash_value.h"
- #include "net/cert/ct_log_verifier_util.h"
- #include "net/cert/merkle_audit_proof.h"
- #include "net/cert/merkle_consistency_proof.h"
- #include "net/cert/signed_certificate_timestamp.h"
- #include "net/cert/signed_tree_head.h"
- #include "net/test/ct_test_util.h"
- #include "testing/gtest/include/gtest/gtest.h"
- namespace net {
- namespace {
- // Calculate the power of two nearest to, but less than, |n|.
- // |n| must be at least 2.
- size_t CalculateNearestPowerOfTwo(size_t n) {
- DCHECK_GT(n, 1u);
- size_t ret = size_t(1) << (sizeof(size_t) * 8 - 1);
- while (ret >= n)
- ret >>= 1;
- return ret;
- }
- // All test data replicated from
- // https://github.com/google/certificate-transparency/blob/c41b090ecc14ddd6b3531dc7e5ce36b21e253fdd/cpp/merkletree/merkle_tree_test.cc
- // The SHA-256 hash of an empty Merkle tree.
- const uint8_t kEmptyTreeHash[32] = {
- 0xe3, 0xb0, 0xc4, 0x42, 0x98, 0xfc, 0x1c, 0x14, 0x9a, 0xfb, 0xf4,
- 0xc8, 0x99, 0x6f, 0xb9, 0x24, 0x27, 0xae, 0x41, 0xe4, 0x64, 0x9b,
- 0x93, 0x4c, 0xa4, 0x95, 0x99, 0x1b, 0x78, 0x52, 0xb8, 0x55};
- std::string GetEmptyTreeHash() {
- return std::string(std::begin(kEmptyTreeHash), std::end(kEmptyTreeHash));
- }
- // SHA-256 Merkle leaf hashes for the sample tree that all of the other test
- // data relates to (8 leaves).
- const char* const kLeafHashes[8] = {
- "6e340b9cffb37a989ca544e6bb780a2c78901d3fb33738768511a30617afa01d",
- "96a296d224f285c67bee93c30f8a309157f0daa35dc5b87e410b78630a09cfc7",
- "0298d122906dcfc10892cb53a73992fc5b9f493ea4c9badb27b791b4127a7fe7",
- "07506a85fd9dd2f120eb694f86011e5bb4662e5c415a62917033d4a9624487e7",
- "bc1a0643b12e4d2d7c77918f44e0f4f79a838b6cf9ec5b5c283e1f4d88599e6b",
- "4271a26be0d8a84f0bd54c8c302e7cb3a3b5d1fa6780a40bcce2873477dab658",
- "b08693ec2e721597130641e8211e7eedccb4c26413963eee6c1e2ed16ffb1a5f",
- "46f6ffadd3d06a09ff3c5860d2755c8b9819db7df44251788c7d8e3180de8eb1"};
- // SHA-256 Merkle root hashes from building the sample tree leaf-by-leaf.
- // The first entry is the root when the tree contains 1 leaf, and the last is
- // the root when the tree contains all 8 leaves.
- const char* const kRootHashes[8] = {
- "6e340b9cffb37a989ca544e6bb780a2c78901d3fb33738768511a30617afa01d",
- "fac54203e7cc696cf0dfcb42c92a1d9dbaf70ad9e621f4bd8d98662f00e3c125",
- "aeb6bcfe274b70a14fb067a5e5578264db0fa9b51af5e0ba159158f329e06e77",
- "d37ee418976dd95753c1c73862b9398fa2a2cf9b4ff0fdfe8b30cd95209614b7",
- "4e3bbb1f7b478dcfe71fb631631519a3bca12c9aefca1612bfce4c13a86264d4",
- "76e67dadbcdf1e10e1b74ddc608abd2f98dfb16fbce75277b5232a127f2087ef",
- "ddb89be403809e325750d3d263cd78929c2942b7942a34b77e122c9594a74c8c",
- "5dc9da79a70659a9ad559cb701ded9a2ab9d823aad2f4960cfe370eff4604328"};
- // A single consistency proof. Contains at most 3 proof nodes (all test proofs
- // will be for a tree of size 8).
- struct ConsistencyProofTestVector {
- size_t old_tree_size;
- size_t new_tree_size;
- size_t proof_length;
- const char* const proof[3];
- };
- // A collection of consistency proofs between various sub-trees of the sample
- // tree.
- const ConsistencyProofTestVector kConsistencyProofs[] = {
- // Empty consistency proof between trees of the same size (1).
- {1, 1, 0, {"", "", ""}},
- // Consistency proof between tree of size 1 and tree of size 8, with 3
- // nodes in the proof.
- {1,
- 8,
- 3,
- {"96a296d224f285c67bee93c30f8a309157f0daa35dc5b87e410b78630a09cfc7",
- "5f083f0a1a33ca076a95279832580db3e0ef4584bdff1f54c8a360f50de3031e",
- "6b47aaf29ee3c2af9af889bc1fb9254dabd31177f16232dd6aab035ca39bf6e4"}},
- // Consistency proof between tree of size 6 and tree of size 8, with 3
- // nodes in the proof.
- {6,
- 8,
- 3,
- {"0ebc5d3437fbe2db158b9f126a1d118e308181031d0a949f8dededebc558ef6a",
- "ca854ea128ed050b41b35ffc1b87b8eb2bde461e9e3b5596ece6b9d5975a0ae0",
- "d37ee418976dd95753c1c73862b9398fa2a2cf9b4ff0fdfe8b30cd95209614b7"}},
- // Consistency proof between tree of size 2 and tree of size 5, with 2
- // nodes in the proof.
- {2,
- 5,
- 2,
- {"5f083f0a1a33ca076a95279832580db3e0ef4584bdff1f54c8a360f50de3031e",
- "bc1a0643b12e4d2d7c77918f44e0f4f79a838b6cf9ec5b5c283e1f4d88599e6b", ""}}};
- // A single audit proof. Contains at most 3 proof nodes (all test proofs will be
- // for a tree of size 8).
- struct AuditProofTestVector {
- size_t leaf;
- size_t tree_size;
- size_t proof_length;
- const char* const proof[3];
- };
- // A collection of audit proofs for various leaves and sub-trees of the tree
- // defined by |kRootHashes|.
- const AuditProofTestVector kAuditProofs[] = {
- {0, 1, 0, {"", "", ""}},
- {0,
- 8,
- 3,
- {"96a296d224f285c67bee93c30f8a309157f0daa35dc5b87e410b78630a09cfc7",
- "5f083f0a1a33ca076a95279832580db3e0ef4584bdff1f54c8a360f50de3031e",
- "6b47aaf29ee3c2af9af889bc1fb9254dabd31177f16232dd6aab035ca39bf6e4"}},
- {5,
- 8,
- 3,
- {"bc1a0643b12e4d2d7c77918f44e0f4f79a838b6cf9ec5b5c283e1f4d88599e6b",
- "ca854ea128ed050b41b35ffc1b87b8eb2bde461e9e3b5596ece6b9d5975a0ae0",
- "d37ee418976dd95753c1c73862b9398fa2a2cf9b4ff0fdfe8b30cd95209614b7"}},
- {2,
- 3,
- 1,
- {"fac54203e7cc696cf0dfcb42c92a1d9dbaf70ad9e621f4bd8d98662f00e3c125", "",
- ""}},
- {1,
- 5,
- 3,
- {"6e340b9cffb37a989ca544e6bb780a2c78901d3fb33738768511a30617afa01d",
- "5f083f0a1a33ca076a95279832580db3e0ef4584bdff1f54c8a360f50de3031e",
- "bc1a0643b12e4d2d7c77918f44e0f4f79a838b6cf9ec5b5c283e1f4d88599e6b"}}};
- // Decodes a hexadecimal string into the binary data it represents.
- std::string HexToBytes(const std::string& hex_data) {
- std::string result;
- if (!base::HexStringToString(hex_data, &result))
- result.clear();
- return result;
- }
- // Constructs a consistency/audit proof from a test vector.
- // This is templated so that it can be used with both ConsistencyProofTestVector
- // and AuditProofTestVector.
- template <typename TestVectorType>
- std::vector<std::string> GetProof(const TestVectorType& test_vector) {
- std::vector<std::string> proof(test_vector.proof_length);
- std::transform(test_vector.proof,
- test_vector.proof + test_vector.proof_length, proof.begin(),
- &HexToBytes);
- return proof;
- }
- // Creates a ct::MerkleConsistencyProof from its arguments and returns the
- // result of passing this to log.VerifyConsistencyProof().
- bool VerifyConsistencyProof(const CTLogVerifier& log,
- size_t old_tree_size,
- const std::string& old_tree_root,
- size_t new_tree_size,
- const std::string& new_tree_root,
- const std::vector<std::string>& proof) {
- return log.VerifyConsistencyProof(
- ct::MerkleConsistencyProof(log.key_id(), proof, old_tree_size,
- new_tree_size),
- old_tree_root, new_tree_root);
- }
- // Creates a ct::MerkleAuditProof from its arguments and returns the result of
- // passing this to log.VerifyAuditProof().
- bool VerifyAuditProof(const CTLogVerifier& log,
- size_t leaf,
- size_t tree_size,
- const std::vector<std::string>& proof,
- const std::string& tree_root,
- const std::string& leaf_hash) {
- return log.VerifyAuditProof(ct::MerkleAuditProof(leaf, tree_size, proof),
- tree_root, leaf_hash);
- }
- class CTLogVerifierTest : public ::testing::Test {
- public:
- void SetUp() override {
- log_ = CTLogVerifier::Create(ct::GetTestPublicKey(), "testlog");
- ASSERT_TRUE(log_);
- EXPECT_EQ(ct::GetTestPublicKeyId(), log_->key_id());
- }
- protected:
- scoped_refptr<const CTLogVerifier> log_;
- };
- // Given an audit proof for a leaf in a Merkle tree, asserts that it verifies
- // and no other combination of leaves, tree sizes and proof nodes verifies.
- void CheckVerifyAuditProof(const CTLogVerifier& log,
- size_t leaf,
- size_t tree_size,
- const std::vector<std::string>& proof,
- const std::string& root_hash,
- const std::string& leaf_hash) {
- EXPECT_TRUE(
- VerifyAuditProof(log, leaf, tree_size, proof, root_hash, leaf_hash))
- << "proof for leaf " << leaf << " did not pass verification";
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf - 1, tree_size, proof, root_hash, leaf_hash))
- << "proof passed verification with wrong leaf index";
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf + 1, tree_size, proof, root_hash, leaf_hash))
- << "proof passed verification with wrong leaf index";
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf ^ 2, tree_size, proof, root_hash, leaf_hash))
- << "proof passed verification with wrong leaf index";
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf, tree_size * 2, proof, root_hash, leaf_hash))
- << "proof passed verification with wrong tree height";
- EXPECT_FALSE(VerifyAuditProof(log, leaf / 2, tree_size / 2, proof, root_hash,
- leaf_hash))
- << "proof passed verification with wrong leaf index and tree height";
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf, tree_size / 2, proof, root_hash, leaf_hash))
- << "proof passed verification with wrong tree height";
- EXPECT_FALSE(VerifyAuditProof(log, leaf, tree_size, proof, GetEmptyTreeHash(),
- leaf_hash))
- << "proof passed verification with wrong root hash";
- std::vector<std::string> wrong_proof;
- // Modify a single element on the proof.
- for (size_t j = 0; j < proof.size(); ++j) {
- wrong_proof = proof;
- wrong_proof[j] = GetEmptyTreeHash();
- EXPECT_FALSE(VerifyAuditProof(log, leaf, tree_size, wrong_proof, root_hash,
- leaf_hash))
- << "proof passed verification with one wrong node (node " << j << ")";
- }
- wrong_proof = proof;
- wrong_proof.emplace_back();
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf, tree_size, wrong_proof, root_hash, leaf_hash))
- << "proof passed verification with an empty node appended";
- wrong_proof.back() = root_hash;
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf, tree_size, wrong_proof, root_hash, leaf_hash))
- << "proof passed verification with an incorrect node appended";
- wrong_proof.pop_back();
- if (!wrong_proof.empty()) {
- wrong_proof.pop_back();
- EXPECT_FALSE(VerifyAuditProof(log, leaf, tree_size, wrong_proof, root_hash,
- leaf_hash))
- << "proof passed verification with the last node missing";
- }
- wrong_proof.clear();
- wrong_proof.emplace_back();
- wrong_proof.insert(wrong_proof.end(), proof.begin(), proof.end());
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf, tree_size, wrong_proof, root_hash, leaf_hash))
- << "proof passed verification with an empty node prepended";
- wrong_proof[0] = root_hash;
- EXPECT_FALSE(
- VerifyAuditProof(log, leaf, tree_size, wrong_proof, root_hash, leaf_hash))
- << "proof passed verification with an incorrect node prepended";
- }
- // Given a consistency proof between two snapshots of the tree, asserts that it
- // verifies and no other combination of tree sizes and proof nodes verifies.
- void CheckVerifyConsistencyProof(const CTLogVerifier& log,
- int old_tree_size,
- int new_tree_size,
- const std::string& old_root,
- const std::string& new_root,
- const std::vector<std::string>& proof) {
- // Verify the original consistency proof.
- EXPECT_TRUE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, proof))
- << "proof between trees of size " << old_tree_size << " and "
- << new_tree_size << " did not pass verification";
- if (proof.empty()) {
- // For simplicity test only non-trivial proofs that have old_root !=
- // new_root
- // old_tree_size != 0 and old_tree_size != new_tree_size.
- return;
- }
- // Wrong tree size: The proof checking code should not accept as a valid proof
- // a proof for a tree size different than the original size it was produced
- // for. Test that this is not the case for off-by-one changes.
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size - 1, old_root,
- new_tree_size, new_root, proof))
- << "proof passed verification with old tree size - 1";
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size + 1, old_root,
- new_tree_size, new_root, proof))
- << "proof passed verification with old tree size + 1";
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size ^ 2, old_root,
- new_tree_size, new_root, proof))
- << "proof passed verification with old tree size ^ 2";
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size * 2, new_root, proof))
- << "proof passed verification with new tree height + 1";
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size / 2, new_root, proof))
- << "proof passed verification with new tree height - 1";
- const std::string wrong_root("WrongRoot");
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, wrong_root, proof))
- << "proof passed verification with wrong old root";
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, wrong_root,
- new_tree_size, new_root, proof))
- << "proof passed verification with wrong new root";
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, new_root,
- new_tree_size, old_root, proof))
- << "proof passed verification with old and new root swapped";
- // Variations of wrong proofs, all of which should be rejected.
- std::vector<std::string> wrong_proof;
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "empty proof passed verification";
- // Modify a single element in the proof.
- for (size_t j = 0; j < proof.size(); ++j) {
- wrong_proof = proof;
- wrong_proof[j] = GetEmptyTreeHash();
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "proof passed verification with incorrect node (node " << j << ")";
- }
- wrong_proof = proof;
- wrong_proof.emplace_back();
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "proof passed verification with empty node appended";
- wrong_proof.back() = proof.back();
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "proof passed verification with last node duplicated";
- wrong_proof.pop_back();
- wrong_proof.pop_back();
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "proof passed verification with last node missing";
- wrong_proof.clear();
- wrong_proof.emplace_back();
- wrong_proof.insert(wrong_proof.end(), proof.begin(), proof.end());
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "proof passed verification with empty node prepended";
- wrong_proof[0] = proof[0];
- EXPECT_FALSE(VerifyConsistencyProof(log, old_tree_size, old_root,
- new_tree_size, new_root, wrong_proof))
- << "proof passed verification with first node duplicated";
- }
- TEST_F(CTLogVerifierTest, VerifiesCertSCT) {
- ct::SignedEntryData cert_entry;
- ct::GetX509CertSignedEntry(&cert_entry);
- scoped_refptr<ct::SignedCertificateTimestamp> cert_sct;
- ct::GetX509CertSCT(&cert_sct);
- EXPECT_TRUE(log_->Verify(cert_entry, *cert_sct.get()));
- }
- TEST_F(CTLogVerifierTest, VerifiesPrecertSCT) {
- ct::SignedEntryData precert_entry;
- ct::GetPrecertSignedEntry(&precert_entry);
- scoped_refptr<ct::SignedCertificateTimestamp> precert_sct;
- ct::GetPrecertSCT(&precert_sct);
- EXPECT_TRUE(log_->Verify(precert_entry, *precert_sct.get()));
- }
- TEST_F(CTLogVerifierTest, FailsInvalidTimestamp) {
- ct::SignedEntryData cert_entry;
- ct::GetX509CertSignedEntry(&cert_entry);
- scoped_refptr<ct::SignedCertificateTimestamp> cert_sct;
- ct::GetX509CertSCT(&cert_sct);
- // Mangle the timestamp, so that it should fail signature validation.
- cert_sct->timestamp = base::Time::Now();
- EXPECT_FALSE(log_->Verify(cert_entry, *cert_sct.get()));
- }
- TEST_F(CTLogVerifierTest, FailsInvalidLogID) {
- ct::SignedEntryData cert_entry;
- ct::GetX509CertSignedEntry(&cert_entry);
- scoped_refptr<ct::SignedCertificateTimestamp> cert_sct;
- ct::GetX509CertSCT(&cert_sct);
- // Mangle the log ID, which should cause it to match a different log before
- // attempting signature validation.
- cert_sct->log_id.assign(cert_sct->log_id.size(), '\0');
- EXPECT_FALSE(log_->Verify(cert_entry, *cert_sct.get()));
- }
- TEST_F(CTLogVerifierTest, VerifiesValidSTH) {
- ct::SignedTreeHead sth;
- ASSERT_TRUE(ct::GetSampleSignedTreeHead(&sth));
- EXPECT_TRUE(log_->VerifySignedTreeHead(sth));
- }
- TEST_F(CTLogVerifierTest, DoesNotVerifyInvalidSTH) {
- ct::SignedTreeHead sth;
- ASSERT_TRUE(ct::GetSampleSignedTreeHead(&sth));
- sth.sha256_root_hash[0] = '\x0';
- EXPECT_FALSE(log_->VerifySignedTreeHead(sth));
- }
- TEST_F(CTLogVerifierTest, VerifiesValidEmptySTH) {
- ct::SignedTreeHead sth;
- ASSERT_TRUE(ct::GetSampleEmptySignedTreeHead(&sth));
- EXPECT_TRUE(log_->VerifySignedTreeHead(sth));
- }
- TEST_F(CTLogVerifierTest, DoesNotVerifyInvalidEmptySTH) {
- ct::SignedTreeHead sth;
- ASSERT_TRUE(ct::GetBadEmptySignedTreeHead(&sth));
- EXPECT_FALSE(log_->VerifySignedTreeHead(sth));
- }
- // Test that excess data after the public key is rejected.
- TEST_F(CTLogVerifierTest, ExcessDataInPublicKey) {
- std::string key = ct::GetTestPublicKey();
- key += "extra";
- scoped_refptr<const CTLogVerifier> log =
- CTLogVerifier::Create(key, "testlog");
- EXPECT_FALSE(log);
- }
- TEST_F(CTLogVerifierTest, VerifiesConsistencyProofEdgeCases_EmptyProof) {
- std::vector<std::string> empty_proof;
- std::string old_root(GetEmptyTreeHash()), new_root(GetEmptyTreeHash());
- // Tree snapshots that are always consistent, because the proofs are either
- // from an empty tree to a non-empty one or for trees of the same size.
- EXPECT_TRUE(
- VerifyConsistencyProof(*log_, 0, old_root, 0, new_root, empty_proof));
- EXPECT_TRUE(
- VerifyConsistencyProof(*log_, 0, old_root, 1, new_root, empty_proof));
- EXPECT_TRUE(
- VerifyConsistencyProof(*log_, 1, old_root, 1, new_root, empty_proof));
- // Invalid consistency proofs.
- // Time travel to the past.
- EXPECT_FALSE(
- VerifyConsistencyProof(*log_, 1, old_root, 0, new_root, empty_proof));
- EXPECT_FALSE(
- VerifyConsistencyProof(*log_, 2, old_root, 1, new_root, empty_proof));
- // Proof between two trees of different size can never be empty.
- EXPECT_FALSE(
- VerifyConsistencyProof(*log_, 1, old_root, 2, new_root, empty_proof));
- }
- TEST_F(CTLogVerifierTest, VerifiesConsistencyProofEdgeCases_MismatchingRoots) {
- const std::string old_root(GetEmptyTreeHash());
- std::string new_root;
- std::vector<std::string> empty_proof;
- // Roots don't match.
- EXPECT_FALSE(
- VerifyConsistencyProof(*log_, 0, old_root, 0, new_root, empty_proof));
- EXPECT_FALSE(
- VerifyConsistencyProof(*log_, 1, old_root, 1, new_root, empty_proof));
- }
- TEST_F(CTLogVerifierTest,
- VerifiesConsistencyProofEdgeCases_MatchingRootsNonEmptyProof) {
- const std::string empty_tree_hash(GetEmptyTreeHash());
- std::vector<std::string> proof;
- proof.push_back(empty_tree_hash);
- // Roots match and the tree size is either the same or the old tree size is 0,
- // but the proof is not empty (the verification code should not accept
- // proofs with redundant nodes in this case).
- proof.push_back(empty_tree_hash);
- EXPECT_FALSE(VerifyConsistencyProof(*log_, 0, empty_tree_hash, 0,
- empty_tree_hash, proof));
- EXPECT_FALSE(VerifyConsistencyProof(*log_, 0, empty_tree_hash, 1,
- empty_tree_hash, proof));
- EXPECT_FALSE(VerifyConsistencyProof(*log_, 1, empty_tree_hash, 1,
- empty_tree_hash, proof));
- }
- class CTLogVerifierConsistencyProofTest
- : public CTLogVerifierTest,
- public ::testing::WithParamInterface<size_t /* proof index */> {};
- // Checks that a sample set of valid consistency proofs verify successfully.
- TEST_P(CTLogVerifierConsistencyProofTest, VerifiesValidConsistencyProof) {
- const ConsistencyProofTestVector& test_vector =
- kConsistencyProofs[GetParam()];
- const std::vector<std::string> proof = GetProof(test_vector);
- const char* const old_root = kRootHashes[test_vector.old_tree_size - 1];
- const char* const new_root = kRootHashes[test_vector.new_tree_size - 1];
- CheckVerifyConsistencyProof(*log_, test_vector.old_tree_size,
- test_vector.new_tree_size, HexToBytes(old_root),
- HexToBytes(new_root), proof);
- }
- INSTANTIATE_TEST_SUITE_P(KnownGoodProofs,
- CTLogVerifierConsistencyProofTest,
- ::testing::Range(size_t(0),
- std::size(kConsistencyProofs)));
- class CTLogVerifierAuditProofTest
- : public CTLogVerifierTest,
- public ::testing::WithParamInterface<size_t /* proof index */> {};
- // Checks that a sample set of valid audit proofs verify successfully.
- TEST_P(CTLogVerifierAuditProofTest, VerifiesValidAuditProofs) {
- const AuditProofTestVector& test_vector = kAuditProofs[GetParam()];
- const std::vector<std::string> proof = GetProof(test_vector);
- const char* const root_hash = kRootHashes[test_vector.tree_size - 1];
- CheckVerifyAuditProof(*log_, test_vector.leaf, test_vector.tree_size, proof,
- HexToBytes(root_hash),
- HexToBytes(kLeafHashes[test_vector.leaf]));
- }
- INSTANTIATE_TEST_SUITE_P(KnownGoodProofs,
- CTLogVerifierAuditProofTest,
- ::testing::Range(size_t(0), std::size(kAuditProofs)));
- TEST_F(CTLogVerifierTest, VerifiesAuditProofEdgeCases_InvalidLeafIndex) {
- std::vector<std::string> proof;
- EXPECT_FALSE(
- VerifyAuditProof(*log_, 1, 0, proof, std::string(), std::string()));
- EXPECT_FALSE(
- VerifyAuditProof(*log_, 2, 1, proof, std::string(), std::string()));
- const std::string empty_hash = GetEmptyTreeHash();
- EXPECT_FALSE(VerifyAuditProof(*log_, 1, 0, proof, empty_hash, std::string()));
- EXPECT_FALSE(VerifyAuditProof(*log_, 2, 1, proof, empty_hash, std::string()));
- }
- // Functions that implement algorithms from RFC6962 necessary for constructing
- // Merkle trees and proofs. This allows tests to generate a variety of trees
- // for exhaustive testing.
- namespace rfc6962 {
- // Calculates the hash of a leaf in a Merkle tree, given its content.
- // See RFC6962, section 2.1.
- std::string HashLeaf(const std::string& leaf) {
- const char kLeafPrefix[] = {'\x00'};
- SHA256HashValue sha256;
- memset(sha256.data, 0, sizeof(sha256.data));
- std::unique_ptr<crypto::SecureHash> hash(
- crypto::SecureHash::Create(crypto::SecureHash::SHA256));
- hash->Update(kLeafPrefix, 1);
- hash->Update(leaf.data(), leaf.size());
- hash->Finish(sha256.data, sizeof(sha256.data));
- return std::string(reinterpret_cast<const char*>(sha256.data),
- sizeof(sha256.data));
- }
- // Calculates the root hash of a Merkle tree, given its leaf data and size.
- // See RFC6962, section 2.1.
- std::string HashTree(std::string leaves[], size_t tree_size) {
- if (tree_size == 0)
- return GetEmptyTreeHash();
- if (tree_size == 1)
- return HashLeaf(leaves[0]);
- // Find the index of the last leaf in the left sub-tree.
- const size_t split = CalculateNearestPowerOfTwo(tree_size);
- // Hash the left and right sub-trees, then hash the results.
- return ct::internal::HashNodes(HashTree(leaves, split),
- HashTree(&leaves[split], tree_size - split));
- }
- // Returns a Merkle audit proof for the leaf with index |leaf_index|.
- // The tree consists of |leaves[0]| to |leaves[tree_size-1]|.
- // If |leaf_index| is >= |tree_size|, an empty proof will be returned.
- // See RFC6962, section 2.1.1, for more details.
- std::vector<std::string> CreateAuditProof(std::string leaves[],
- size_t tree_size,
- size_t leaf_index) {
- std::vector<std::string> proof;
- if (leaf_index >= tree_size)
- return proof;
- if (tree_size == 1)
- return proof;
- // Find the index of the first leaf in the right sub-tree.
- const size_t split = CalculateNearestPowerOfTwo(tree_size);
- // Recurse down the correct branch of the tree (left or right) to reach the
- // leaf with |leaf_index|. Add the hash of the branch not taken at each step
- // on the way up to build the proof.
- if (leaf_index < split) {
- proof = CreateAuditProof(leaves, split, leaf_index);
- proof.push_back(HashTree(&leaves[split], tree_size - split));
- } else {
- proof =
- CreateAuditProof(&leaves[split], tree_size - split, leaf_index - split);
- proof.push_back(HashTree(leaves, split));
- }
- return proof;
- }
- // Returns a Merkle consistency proof between two Merkle trees.
- // The old tree contains |leaves[0]| to |leaves[old_tree_size-1]|.
- // The new tree contains |leaves[0]| to |leaves[new_tree_size-1]|.
- // Call with |contains_old_tree| = true.
- // See RFC6962, section 2.1.2, for more details.
- std::vector<std::string> CreateConsistencyProof(std::string leaves[],
- size_t new_tree_size,
- size_t old_tree_size,
- bool contains_old_tree = true) {
- std::vector<std::string> proof;
- if (old_tree_size == 0 || old_tree_size > new_tree_size)
- return proof;
- if (old_tree_size == new_tree_size) {
- // Consistency proof for two equal subtrees is empty.
- if (!contains_old_tree) {
- // Record the hash of this subtree unless it's the root for which
- // the proof was originally requested. (This happens when the old tree is
- // balanced).
- proof.push_back(HashTree(leaves, old_tree_size));
- }
- return proof;
- }
- // Find the index of the last leaf in the left sub-tree.
- const size_t split = CalculateNearestPowerOfTwo(new_tree_size);
- if (old_tree_size <= split) {
- // Root of the old tree is in the left subtree of the new tree.
- // Prove that the left subtrees are consistent.
- proof =
- CreateConsistencyProof(leaves, split, old_tree_size, contains_old_tree);
- // Record the hash of the right subtree (only present in the new tree).
- proof.push_back(HashTree(&leaves[split], new_tree_size - split));
- } else {
- // The old tree root is at the same level as the new tree root.
- // Prove that the right subtrees are consistent. The right subtree
- // doesn't contain the root of the old tree, so set contains_old_tree =
- // false.
- proof = CreateConsistencyProof(&leaves[split], new_tree_size - split,
- old_tree_size - split,
- /* contains_old_tree = */ false);
- // Record the hash of the left subtree (equal in both trees).
- proof.push_back(HashTree(leaves, split));
- }
- return proof;
- }
- } // namespace rfc6962
- class CTLogVerifierTestUsingGenerator
- : public CTLogVerifierTest,
- public ::testing::WithParamInterface<size_t /* tree_size */> {};
- // Checks that valid consistency proofs for a range of generated Merkle trees
- // verify successfully.
- TEST_P(CTLogVerifierTestUsingGenerator, VerifiesValidConsistencyProof) {
- const size_t tree_size = GetParam();
- std::vector<std::string> tree_leaves(tree_size);
- for (size_t i = 0; i < tree_size; ++i)
- tree_leaves[i].push_back(static_cast<char>(i));
- const std::string tree_root =
- rfc6962::HashTree(tree_leaves.data(), tree_size);
- // Check consistency proofs for every sub-tree.
- for (size_t old_tree_size = 0; old_tree_size <= tree_size; ++old_tree_size) {
- SCOPED_TRACE(old_tree_size);
- const std::string old_tree_root =
- rfc6962::HashTree(tree_leaves.data(), old_tree_size);
- const std::vector<std::string> proof = rfc6962::CreateConsistencyProof(
- tree_leaves.data(), tree_size, old_tree_size);
- // Checks that the consistency proof verifies only with the correct tree
- // sizes and root hashes.
- CheckVerifyConsistencyProof(*log_, old_tree_size, tree_size, old_tree_root,
- tree_root, proof);
- }
- }
- // Checks that valid audit proofs for a range of generated Merkle trees verify
- // successfully.
- TEST_P(CTLogVerifierTestUsingGenerator, VerifiesValidAuditProofs) {
- const size_t tree_size = GetParam();
- std::vector<std::string> tree_leaves(tree_size);
- for (size_t i = 0; i < tree_size; ++i)
- tree_leaves[i].push_back(static_cast<char>(i));
- const std::string root = rfc6962::HashTree(tree_leaves.data(), tree_size);
- // Check audit proofs for every leaf in the tree.
- for (size_t leaf = 0; leaf < tree_size; ++leaf) {
- SCOPED_TRACE(leaf);
- std::vector<std::string> proof =
- rfc6962::CreateAuditProof(tree_leaves.data(), tree_size, leaf);
- // Checks that the audit proof verifies only for this leaf data, index,
- // hash, tree size and root hash.
- CheckVerifyAuditProof(*log_, leaf, tree_size, proof, root,
- rfc6962::HashLeaf(tree_leaves[leaf]));
- }
- }
- // Test verification of consistency proofs and audit proofs for all tree sizes
- // from 0 to 128.
- INSTANTIATE_TEST_SUITE_P(RangeOfTreeSizes,
- CTLogVerifierTestUsingGenerator,
- testing::Range(size_t(0), size_t(129)));
- } // namespace
- } // namespace net
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