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Implement monitoring verification #134

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Implement monitoring verification #134

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2 changes: 1 addition & 1 deletion client/coniksclient/internal/cmd/run.go
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Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,7 @@ func init() {
func run(cmd *cobra.Command) {
isDebugging, _ := strconv.ParseBool(cmd.Flag("debug").Value.String())
conf := loadConfigOrExit(cmd)
cc := p.NewCC(nil, true, conf.SigningPubKey)
cc := p.NewCC(nil, conf.SigningPubKey, nil, true, nil)

state, err := terminal.MakeRaw(int(os.Stdin.Fd()))
if err != nil {
Expand Down
103 changes: 91 additions & 12 deletions protocol/consistencychecks.go
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,15 @@ import (
type ConsistencyChecks struct {
// SavedSTR stores the latest verified signed tree root.
SavedSTR *DirSTR
// Bindings stores all the verified name-to-key bindings.
Bindings map[string][]byte
// RegEpoch keeps the registration epoch of each user.
// Entries are kept even the binding was inserted into the directory.
RegEpoch map[string]uint64

// oldSTR stores the previous verified STR.
// This is used as a cache to verify the TB.
oldSTR *DirSTR

// extensions settings
useTBs bool
Expand All @@ -39,7 +47,8 @@ type ConsistencyChecks struct {
// NewCC creates an instance of ConsistencyChecks using
// a CONIKS directory's pinned STR at epoch 0, or
// the consistency state read from persistent storage.
func NewCC(savedSTR *DirSTR, useTBs bool, signKey sign.PublicKey) *ConsistencyChecks {
func NewCC(savedSTR *DirSTR, signKey sign.PublicKey, regs map[string]uint64,
useTBs bool, tbs map[string]*TemporaryBinding) *ConsistencyChecks {
// TODO: see #110
if !useTBs {
panic("[coniks] Currently the server is forced to use TBs")
Expand All @@ -49,9 +58,18 @@ func NewCC(savedSTR *DirSTR, useTBs bool, signKey sign.PublicKey) *ConsistencyCh
Bindings: make(map[string][]byte),
useTBs: useTBs,
signKey: signKey,
RegEpoch: regs,
oldSTR: savedSTR,
}
if len(regs) == 0 {
cc.RegEpoch = make(map[string]uint64)
}
if useTBs {
cc.TBs = make(map[string]*TemporaryBinding)
if tbs == nil {
cc.TBs = make(map[string]*TemporaryBinding)
} else {
cc.TBs = tbs
}
}
return cc
}
Expand Down Expand Up @@ -79,8 +97,8 @@ func (cc *ConsistencyChecks) HandleResponse(requestType int, msg *Response,
if _, ok := msg.DirectoryResponse.(*DirectoryProof); !ok {
return ErrMalformedDirectoryMessage
}
case MonitoringType, KeyLookupInEpochType:
if _, ok := msg.DirectoryResponse.(*DirectoryProofs); !ok {
case MonitoringType:
if _, ok := msg.DirectoryResponse.(*DirectoryProofs); !ok || msg.Error != ReqSuccess {
return ErrMalformedDirectoryMessage
}
default:
Expand Down Expand Up @@ -118,9 +136,34 @@ func (cc *ConsistencyChecks) updateSTR(requestType int, msg *Response) error {
}
// Otherwise, expect that we've entered a new epoch
if err := cc.verifySTRConsistency(cc.SavedSTR, str); err != nil {
// FIXME: this check should be removed (see #173)
return err
}

case MonitoringType:
// FIXME: we are returning the error immediately
// without saving the inconsistent STR
// see: https://github.com/coniks-sys/coniks-go/pull/74#commitcomment-19804686
strs := msg.DirectoryResponse.(*DirectoryProofs).STR
switch {
case strs[0].Epoch == cc.SavedSTR.Epoch:
if err := cc.verifySTR(strs[0]); err != nil {
return err
}
case strs[0].Epoch == cc.SavedSTR.Epoch+1:
if err := cc.verifySTRConsistency(cc.SavedSTR, strs[0]); err != nil {
return err
}
default:
return CheckUnexpectedMonitoringEpoch
}

for i := 1; i < len(strs); i++ {
if err := cc.verifySTRConsistency(strs[i-1], strs[i]); err != nil {
return err
}
}
str = strs[len(strs)-1]
default:
panic("[coniks] Unknown request type")
}
Expand All @@ -132,6 +175,9 @@ func (cc *ConsistencyChecks) updateSTR(requestType int, msg *Response) error {

// verifySTR checks whether the received STR is the same with
// the SavedSTR using reflect.DeepEqual().
// FIXME: check whether the STR was issued on time and whatnot.
// Maybe it has something to do w/ #81 and client transitioning between epochs.
// Try to verify w/ what's been saved
func (cc *ConsistencyChecks) verifySTR(str *DirSTR) error {
if reflect.DeepEqual(cc.SavedSTR, str) {
return nil
Expand Down Expand Up @@ -163,6 +209,8 @@ func (cc *ConsistencyChecks) checkConsistency(requestType int, msg *Response,
err = cc.verifyRegistration(msg, uname, key)
case KeyLookupType:
err = cc.verifyKeyLookup(msg, uname, key)
case MonitoringType:
err = cc.verifyMonitoring(msg, uname, key)
default:
panic("[coniks] Unknown request type")
}
Expand Down Expand Up @@ -214,6 +262,28 @@ func (cc *ConsistencyChecks) verifyKeyLookup(msg *Response,
return CheckPassed
}

func (cc *ConsistencyChecks) verifyMonitoring(msg *Response,
uname string, key []byte) error {
if _, ok := cc.RegEpoch[uname]; !ok {
// TODO: panic for now since we haven't supported #106 yet
panic("[coniks] Cannot perform monitoring for unregistered user name")
}

dfs := msg.DirectoryResponse.(*DirectoryProofs)
for i := 0; i < len(dfs.STR); i++ {
str := dfs.STR[i]
ap := dfs.AP[i]
if ap.ProofType() != m.ProofOfInclusion {
return CheckBadAuthPath
}
if err := verifyAuthPath(uname, key, ap, str); err != nil {
return err
}
}

return CheckPassed
}

func verifyAuthPath(uname string, key []byte, ap *m.AuthenticationPath, str *DirSTR) error {
// verify VRF Index
vrfKey := str.Policies.VrfPublicKey
Expand Down Expand Up @@ -256,20 +326,22 @@ func (cc *ConsistencyChecks) updateTBs(requestType int, msg *Response,
return err
}
cc.TBs[uname] = df.TB
cc.RegEpoch[uname] = cc.SavedSTR.Epoch
}
return nil

case KeyLookupType:
df := msg.DirectoryResponse.(*DirectoryProof)
ap := df.AP
str := df.STR
proofType := ap.ProofType()
switch {
case msg.Error == ReqSuccess && proofType == m.ProofOfInclusion:
if err := cc.verifyFulfilledPromise(uname, str, ap); err != nil {
return err
}
delete(cc.TBs, uname)
// FIXME: We don' support this for now,
// until we know how to cache the issued epoch. (See #116)
// case msg.Error == ReqSuccess && proofType == m.ProofOfInclusion:
// if err := cc.verifyFulfilledPromise(uname, str, ap); err != nil {
// return err
// }
// delete(cc.TBs, uname)

case msg.Error == ReqSuccess && proofType == m.ProofOfAbsence:
if err := cc.verifyReturnedPromise(df, key); err != nil {
Expand All @@ -278,6 +350,13 @@ func (cc *ConsistencyChecks) updateTBs(requestType int, msg *Response,
cc.TBs[uname] = df.TB
}

case MonitoringType:
dfs := msg.DirectoryResponse.(*DirectoryProofs)
if err := cc.verifyFulfilledPromise(uname, dfs.STR[0], dfs.AP[0]); err != nil {
return err
}
delete(cc.TBs, uname)

default:
panic("[coniks] Unknown request type")
}
Expand All @@ -288,9 +367,9 @@ func (cc *ConsistencyChecks) updateTBs(requestType int, msg *Response,
// in the directory as promised.
func (cc *ConsistencyChecks) verifyFulfilledPromise(uname string, str *DirSTR,
ap *m.AuthenticationPath) error {
// FIXME: Which epoch did this lookup happen in?
if tb, ok := cc.TBs[uname]; ok {
if !bytes.Equal(ap.LookupIndex, tb.Index) ||
if cc.oldSTR.Epoch+1 != str.Epoch ||
!bytes.Equal(ap.LookupIndex, tb.Index) ||
!bytes.Equal(ap.Leaf.Value, tb.Value) {
return CheckBrokenPromise
}
Expand Down
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