From 24eb746adec654637f88ae185012dc984cf9b2dc Mon Sep 17 00:00:00 2001
From: Rasmus Dahlberg <rasmus.dahlberg@kau.se>
Date: Fri, 30 Oct 2020 18:10:49 +0100
Subject: added sanity checks on Trillian responses

Based on the sanity checks that CTFE does.
---
 trillian.go | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 59 insertions(+), 4 deletions(-)

(limited to 'trillian.go')

diff --git a/trillian.go b/trillian.go
index e5117da..147c5bd 100644
--- a/trillian.go
+++ b/trillian.go
@@ -5,28 +5,83 @@ import (
 
 	"net/http"
 
+	"github.com/golang/glog"
 	"github.com/google/trillian"
 	"github.com/google/trillian/types"
+	"google.golang.org/grpc/codes"
 )
 
-// checkGetLeavesByRange does santity-checking on a Trillian response
-func checkGetLeavesByRange(rsp *trillian.GetLeavesByRangeResponse, req GetEntriesRequest) (int, error) {
+func checkQueueLeaf(rsp *trillian.QueueLeafResponse) (int, error) {
+	if codes.Code(rsp.QueuedLeaf.GetStatus().GetCode()) == codes.AlreadyExists {
+		// no need to report this as an invalid request, just (re)issue sdi
+		glog.V(3).Infof("queued leaf is a duplicate => %X", rsp.QueuedLeaf.Leaf.LeafValue)
+	} else {
+		glog.V(3).Infof("queued leaf => %X", rsp.QueuedLeaf.Leaf.LeafValue)
+	}
+	return 0, nil
+}
+
+func checkGetLeavesByRange(rsp *trillian.GetLeavesByRangeResponse, req *GetEntriesRequest) (int, error) {
 	if len(rsp.Leaves) > int(req.End-req.Start+1) {
 		return http.StatusInternalServerError, fmt.Errorf("backend GetLeavesByRange returned too many leaves: %d for [%d,%d]", len(rsp.Leaves), req.Start, req.End)
 	}
 
+	// Ensure that a bad start parameter results in an error
 	var lr types.LogRootV1
 	if err := lr.UnmarshalBinary(rsp.GetSignedLogRoot().GetLogRoot()); err != nil {
 		return http.StatusInternalServerError, fmt.Errorf("failed unmarshaling log root: %v", err)
 	}
 	if uint64(req.Start) >= lr.TreeSize {
-		return http.StatusBadRequest, fmt.Errorf("invalid start(%d): tree size is %d", req.Start, lr.TreeSize)
+		return http.StatusNotFound, fmt.Errorf("invalid start(%d): tree size is %d", req.Start, lr.TreeSize)
 	}
 
+	// Ensure that we got and return expected leaf indices
 	for i, leaf := range rsp.Leaves {
 		if leaf.LeafIndex != req.Start+int64(i) {
-			return http.StatusInternalServerError, fmt.Errorf("backend GetLeavesByRange returned unexpected leaf index: wanted %d, got %d", req.Start+int64(i), leaf.LeafIndex)
+			return http.StatusInternalServerError, fmt.Errorf("invalid leaf index: wanted %d, got %d", req.Start+int64(i), leaf.LeafIndex)
 		}
 	}
 	return 0, nil
 }
+
+func checkGetInclusionProofByHash(rsp *trillian.GetInclusionProofByHashResponse, lp *LogParameters) (int, error) {
+	if rsp.Proof == nil || len(rsp.Proof) == 0 {
+		return http.StatusNotFound, fmt.Errorf("incomplete backend response")
+	} // maybe redundant, but better safe than sorry
+	return checkHashPath(lp.HashType.Size(), rsp.Proof[0].Hashes)
+}
+
+func checkGetConsistencyProofResponse(rsp *trillian.GetConsistencyProofResponse, lp *LogParameters) (int, error) {
+	if rsp.Proof == nil {
+		return http.StatusNotFound, fmt.Errorf("incomplete backend response")
+	} // not redundant, out-of-range parameters yield an empty proof w/o error
+	return checkHashPath(lp.HashType.Size(), rsp.Proof.Hashes)
+}
+
+func checkTrillianGetLatestSignedLogRoot(rsp *trillian.GetLatestSignedLogRootResponse, lp *LogParameters) (int, error) {
+	if rsp.SignedLogRoot == nil {
+		return http.StatusInternalServerError, fmt.Errorf("incomplete backend response")
+	} // maybe redundant
+
+	var lr types.LogRootV1
+	if err := lr.UnmarshalBinary(rsp.GetSignedLogRoot().GetLogRoot()); err != nil {
+		return http.StatusInternalServerError, fmt.Errorf("failed unmarshaling log root: %v", err)
+	}
+	if len(lr.RootHash) != lp.HashType.Size() {
+		return http.StatusInternalServerError, fmt.Errorf("invalid root hash: %v", lr.RootHash)
+	} // maybe redundant, but would not necessarily be caught by marshal error
+	return 0, nil
+}
+
+func checkHashPath(hashSize int, path [][]byte) (int, error) {
+	for _, hash := range path {
+		if len(hash) != hashSize {
+			return http.StatusInternalServerError, fmt.Errorf("invalid proof: %v", path)
+		}
+	} // maybe redundant, but would not necessarily be caught by marshal error
+	return 0, nil
+}
+
+func checkLogRoot(hashSize int, rootHash []byte) (int, error) {
+	return 0, nil
+}
-- 
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