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authorLinus Nordberg <linus@nordberg.se>2022-07-19 18:12:39 +0200
committerLinus Nordberg <linus@nordberg.se>2022-07-19 18:12:39 +0200
commit1dc5cc44945cb13c9401d8f8ae2bfa8bfe0162d5 (patch)
tree0409d6ad00293671120ea620459fe93181563e2c /internal/state/single.go
parent387914dfcfda0f84f13b4d49f5b2371867cace46 (diff)
verify secondary consistency against proposed treev0.5.1
... and not against latest published. Also, improve comments in code.
Diffstat (limited to 'internal/state/single.go')
-rw-r--r--internal/state/single.go35
1 files changed, 16 insertions, 19 deletions
diff --git a/internal/state/single.go b/internal/state/single.go
index 2c6bb4b..6817531 100644
--- a/internal/state/single.go
+++ b/internal/state/single.go
@@ -155,7 +155,6 @@ func (sm *StateManagerSingle) chooseTree(ctx context.Context, proposedTreeHead *
log.Error("secondary is ahead of us: %d > %d", secSTH.TreeSize, proposedTreeHead.TreeSize)
return refreshTreeHead(sm.signedTreeHead.TreeHead)
}
-
if secSTH.TreeSize == proposedTreeHead.TreeSize {
if secSTH.RootHash != proposedTreeHead.RootHash {
log.Error("secondary root hash doesn't match our root hash at tree size %d", secSTH.TreeSize)
@@ -164,27 +163,26 @@ func (sm *StateManagerSingle) chooseTree(ctx context.Context, proposedTreeHead *
log.Debug("secondary is up-to-date with matching tree head, using proposed tree, size %d", proposedTreeHead.TreeSize)
return proposedTreeHead
}
- //
- // Now we know that the proposed tree size is larger than the secondary's tree size.
- // We also now that the secondary's minimum tree size is 0.
- // This means that the proposed tree size is at least 1.
- //
- // Case 1: secondary tree size is 0, primary tree size is >0 --> return based on what we signed before
- // Case 2: secondary tree size is 1, primary tree size is >1 --> fetch consistency proof, if ok ->
- // 2a) secondary tree size is smaller than or equal to what we than signed before -> return whatever we signed before
- // 2b) secondary tree size is larger than what we signed before -> return secondary tree head
- //
- // (If not ok in case 2, return based on what we signed before)
- //
+ // We now know that
+ // * the proposed tree is ahead of the secondary (including them not being equal)
+ // * the minimal tree size is 0, so the proposed tree is at tree size 1 or greater
+
+ // Consistency proofs can not be produced from a tree of size 0, so don't try when the secondary is at 0.
if secSTH.TreeSize == 0 {
+ log.Debug("secondary tree size is zero, using latest published tree head: size %d", sm.signedTreeHead.TreeSize)
return refreshTreeHead(sm.signedTreeHead.TreeHead)
}
- if err := sm.verifyConsistencyWithLatest(ctx, secSTH.TreeHead); err != nil {
- log.Error("secondaries tree not consistent with ours: %v", err)
+ if err := sm.verifyConsistency(ctx, &secSTH.TreeHead, proposedTreeHead); err != nil {
+ log.Error("secondary tree not consistent with ours: %v", err)
return refreshTreeHead(sm.signedTreeHead.TreeHead)
}
- if secSTH.TreeSize <= sm.signedTreeHead.TreeSize {
- log.Warning("secondary is behind what primary already signed: %d <= %d", secSTH.TreeSize, sm.signedTreeHead.TreeSize)
+ // We now know that
+ // * we have two candidates: latest published and secondary's tree
+ // * secondary's tree is verified to be consistent with our proposed tree
+
+ // Protect against going backwards by chosing the larger of secondary tree and latest published.
+ if sm.signedTreeHead.TreeSize > secSTH.TreeHead.TreeSize {
+ log.Debug("using latest published tree head: size %d", sm.signedTreeHead.TreeSize)
return refreshTreeHead(sm.signedTreeHead.TreeHead)
}
@@ -192,8 +190,7 @@ func (sm *StateManagerSingle) chooseTree(ctx context.Context, proposedTreeHead *
return refreshTreeHead(secSTH.TreeHead)
}
-func (sm *StateManagerSingle) verifyConsistencyWithLatest(ctx context.Context, to types.TreeHead) error {
- from := sm.signedTreeHead.TreeHead
+func (sm *StateManagerSingle) verifyConsistency(ctx context.Context, from, to *types.TreeHead) error {
req := &requests.ConsistencyProof{
OldSize: from.TreeSize,
NewSize: to.TreeSize,