From 0c751f0294443aec2bb154a8ea475d0477ba643d Mon Sep 17 00:00:00 2001 From: Andrew Ayer Date: Thu, 5 Jan 2017 21:06:37 -0800 Subject: [PATCH] Drop the MerkleTreeBuilder return value from VerifyConsistencyProof --- auditing.go | 32 +++++++++++++------------------- cmd/common.go | 4 ++-- scanner.go | 9 ++++----- 3 files changed, 19 insertions(+), 26 deletions(-) diff --git a/auditing.go b/auditing.go index f03006e..67d1faf 100644 --- a/auditing.go +++ b/auditing.go @@ -24,18 +24,17 @@ func reverseHashes(hashes []ct.MerkleTreeNode) { } } -// TODO: drop the MerkleTreeBuilder return value -func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, second *ct.SignedTreeHead) (bool, *MerkleTreeBuilder) { +func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, second *ct.SignedTreeHead) bool { // TODO: make sure every hash in proof is right length? otherwise input to hashChildren is ambiguous if second.TreeSize < first.TreeSize { // Can't be consistent if tree got smaller - return false, nil + return false } if first.TreeSize == second.TreeSize { if !(bytes.Equal(first.SHA256RootHash[:], second.SHA256RootHash[:]) && len(proof) == 0) { - return false, nil + return false } - return true, &MerkleTreeBuilder{stack: []ct.MerkleTreeNode{first.SHA256RootHash[:]}, numLeaves: 1} + return true } if first.TreeSize == 0 { // The purpose of the consistency proof is to ensure the append-only @@ -43,9 +42,9 @@ func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, // second tree. If the first tree is empty, then it's trivially a prefix // of the second tree, so no proof is needed. if len(proof) != 0 { - return false, nil + return false } - return true, &MerkleTreeBuilder{stack: []ct.MerkleTreeNode{}, numLeaves: 0} + return true } // Guaranteed that 0 < first.TreeSize < second.TreeSize @@ -58,12 +57,11 @@ func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, lastNode /= 2 } - var leftHashes []ct.MerkleTreeNode var newHash ct.MerkleTreeNode var oldHash ct.MerkleTreeNode if node > 0 { if len(proof) == 0 { - return false, nil + return false } newHash = proof[0] proof = proof[1:] @@ -72,22 +70,20 @@ func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, newHash = first.SHA256RootHash[:] } oldHash = newHash - leftHashes = append(leftHashes, newHash) for node > 0 { if node%2 == 1 { // node is a right child; left sibling exists in both trees if len(proof) == 0 { - return false, nil + return false } newHash = hashChildren(proof[0], newHash) oldHash = hashChildren(proof[0], oldHash) - leftHashes = append(leftHashes, proof[0]) proof = proof[1:] } else if node < lastNode { // node is a left child; rigth sibling only exists in the new tree if len(proof) == 0 { - return false, nil + return false } newHash = hashChildren(newHash, proof[0]) proof = proof[1:] @@ -97,13 +93,13 @@ func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, } if !bytes.Equal(oldHash, first.SHA256RootHash[:]) { - return false, nil + return false } // If trees have different height, continue up the path to reach the new root for lastNode > 0 { if len(proof) == 0 { - return false, nil + return false } newHash = hashChildren(newHash, proof[0]) proof = proof[1:] @@ -111,12 +107,10 @@ func VerifyConsistencyProof(proof ct.ConsistencyProof, first *ct.SignedTreeHead, } if !bytes.Equal(newHash, second.SHA256RootHash[:]) { - return false, nil + return false } - reverseHashes(leftHashes) - - return true, &MerkleTreeBuilder{stack: leftHashes, numLeaves: first.TreeSize} + return true } func hashNothing() ct.MerkleTreeNode { diff --git a/cmd/common.go b/cmd/common.go index 5b0bd52..56ac641 100644 --- a/cmd/common.go +++ b/cmd/common.go @@ -176,7 +176,7 @@ func (ctlog *logHandle) audit () error { for _, sth := range sths { if sth.TreeSize > ctlog.verifiedSTH.TreeSize { - isValid, _, _, err := ctlog.scanner.CheckConsistency(ctlog.verifiedSTH, sth) + isValid, err := ctlog.scanner.CheckConsistency(ctlog.verifiedSTH, sth) if err != nil { return fmt.Errorf("Error fetching consistency proof between %d and %d (if this error persists, it should be construed as misbehavior by the log): %s", ctlog.verifiedSTH.TreeSize, sth.TreeSize, err) } @@ -188,7 +188,7 @@ func (ctlog *logHandle) audit () error { return fmt.Errorf("Error storing verified STH: %s", err) } } else if sth.TreeSize < ctlog.verifiedSTH.TreeSize { - isValid, _, _, err := ctlog.scanner.CheckConsistency(sth, ctlog.verifiedSTH) + isValid, err := ctlog.scanner.CheckConsistency(sth, ctlog.verifiedSTH) if err != nil { return fmt.Errorf("Error fetching consistency proof between %d and %d (if this error persists, it should be construed as misbehavior by the log): %s", ctlog.verifiedSTH.TreeSize, sth.TreeSize, err) } diff --git a/scanner.go b/scanner.go index f3e88a1..41ba6da 100644 --- a/scanner.go +++ b/scanner.go @@ -211,12 +211,12 @@ func (s *Scanner) GetSTH() (*ct.SignedTreeHead, error) { return latestSth, nil } -func (s *Scanner) CheckConsistency(first *ct.SignedTreeHead, second *ct.SignedTreeHead) (bool, *MerkleTreeBuilder, ct.ConsistencyProof, error) { +func (s *Scanner) CheckConsistency(first *ct.SignedTreeHead, second *ct.SignedTreeHead) (bool, error) { var proof ct.ConsistencyProof if first.TreeSize > second.TreeSize { // No way this can be valid - return false, nil, nil, nil + return false, nil } else if first.TreeSize == second.TreeSize { // The proof *should* be empty, so don't bother contacting the server. // This is necessary because the digicert server returns a 400 error if first==second. @@ -225,12 +225,11 @@ func (s *Scanner) CheckConsistency(first *ct.SignedTreeHead, second *ct.SignedTr var err error proof, err = s.logClient.GetConsistencyProof(int64(first.TreeSize), int64(second.TreeSize)) if err != nil { - return false, nil, nil, err + return false, err } } - valid, treeBuilder := VerifyConsistencyProof(proof, first, second) - return valid, treeBuilder, proof, nil + return VerifyConsistencyProof(proof, first, second), nil } func (s *Scanner) MakeMerkleTreeBuilder(sth *ct.SignedTreeHead) (*MerkleTreeBuilder, error) {