From 6577d92928edb8b80448c9bfebb02e62b6d46257 Mon Sep 17 00:00:00 2001
From: Marcela Melara <msmelara@gmail.com>
Date: Thu, 16 Feb 2017 15:20:16 -0500
Subject: [PATCH] Use single generic verifySTRConsistency to be used by client
 and auditor

---
 protocol/auditlog.go          | 20 +-------------------
 protocol/consistencychecks.go | 15 +++++++++------
 2 files changed, 10 insertions(+), 25 deletions(-)

diff --git a/protocol/auditlog.go b/protocol/auditlog.go
index 3f50141..373a7f4 100644
--- a/protocol/auditlog.go
+++ b/protocol/auditlog.go
@@ -100,7 +100,7 @@ func (l *ConiksAuditLog) Update(addr string, newSTR *m.SignedTreeRoot) error {
 
 	h := l.histories[addr]
 
-	if err := h.verifySTRConsistency(newSTR); err != nil {
+	if err := verifySTRConsistency(h.signKey, h.latestSTR, newSTR); err != nil {
 		return err
 	}
 
@@ -110,24 +110,6 @@ func (l *ConiksAuditLog) Update(addr string, newSTR *m.SignedTreeRoot) error {
 	return nil
 }
 
-// verifySTRConsistency checks the consistency between 2 snapshots.
-// It uses the pinned signing key in the directory history
-// to verify the STR's signature and verifies
-// the hash chain using the latestSTR stored in the history.
-// TODO: dedup this: write generic verifySTRConsistency
-func (h *directoryHistory) verifySTRConsistency(str *m.SignedTreeRoot) error {
-	// verify STR's signature
-	if !h.signKey.Verify(str.Serialize(), str.Signature) {
-		return CheckBadSignature
-	}
-	if str.VerifyHashChain(h.latestSTR) {
-		return nil
-	}
-
-	// TODO: verify the directory's policies as well. See #115
-	return CheckBadSTR
-}
-
 // GetObservedSTR gets the observed STR for the CONIKS directory address indicated
 // in the AuditingRequest req received from a CONIKS client from the auditor's latest
 // directory history entry, and returns a tuple of the form
diff --git a/protocol/consistencychecks.go b/protocol/consistencychecks.go
index ba4a19e..a6d5840 100644
--- a/protocol/consistencychecks.go
+++ b/protocol/consistencychecks.go
@@ -117,7 +117,7 @@ func (cc *ConsistencyChecks) updateSTR(requestType int, msg *Response) error {
 			return nil
 		}
 		// Otherwise, expect that we've entered a new epoch
-		if err := cc.verifySTRConsistency(cc.SavedSTR, str); err != nil {
+		if err := verifySTRConsistency(cc.signKey, cc.SavedSTR, str); err != nil {
 			return err
 		}
 
@@ -140,12 +140,15 @@ func (cc *ConsistencyChecks) verifySTR(str *m.SignedTreeRoot) error {
 }
 
 // verifySTRConsistency checks the consistency between 2 snapshots.
-// It uses the pinned signing key in cc
-// to verify the STR's signature and should not verify
-// the hash chain using the STR stored in cc.
-func (cc *ConsistencyChecks) verifySTRConsistency(savedSTR, str *m.SignedTreeRoot) error {
+// It uses the signing key signKey to verify the STR's signature.
+// The signKey param either comes from a client's
+// pinned signing key in cc, or an auditor's pinned signing key
+// in its history.
+// In the case of a client-side consistency check, verifySTRConsistency()
+// should not verify the hash chain using the STR stored in cc.
+func verifySTRConsistency(signKey sign.PublicKey, savedSTR, str *m.SignedTreeRoot) error {
 	// verify STR's signature
-	if !cc.signKey.Verify(str.Serialize(), str.Signature) {
+	if !signKey.Verify(str.Serialize(), str.Signature) {
 		return CheckBadSignature
 	}
 	if str.VerifyHashChain(savedSTR) {