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// This file is part of gnunet-go, a GNUnet-implementation in Golang.
// Copyright (C) 2019-2022 Bernd Fix >Y<
//
// gnunet-go is free software: you can redistribute it and/or modify it
// under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// gnunet-go is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: AGPL3.0-or-later
package revocation
import (
"context"
"gnunet/config"
"gnunet/core"
"gnunet/crypto"
"gnunet/enums"
"gnunet/service"
"gnunet/service/store"
"gnunet/util"
"net/http"
"github.com/bfix/gospel/data"
"github.com/bfix/gospel/logger"
)
//======================================================================
// "GNUnet Revocation" implementation
//======================================================================
// The minimum average difficulty acceptable for a set of revocation PoWs
const MinAvgDifficulty = 23
// Module handles the revocation-related calls to other modules.
type Module struct {
service.ModuleImpl
bloomf *data.BloomFilter // bloomfilter for fast revocation check
kvs store.KVStore // storage for known revocations
}
// NewModule returns an initialized revocation module
func NewModule(ctx context.Context, c *core.Core) (m *Module) {
// create and init instance
m = &Module{
ModuleImpl: *service.NewModuleImpl(),
}
init := func() (err error) {
// Initialize access to revocation data storage
if m.kvs, err = store.NewKVStore(config.Cfg.Revocation.Storage); err != nil {
return
}
// traverse the storage and build bloomfilter for all keys
m.bloomf = data.NewBloomFilter(1000000, 1e-8)
var keys []string
if keys, err = m.kvs.List(); err != nil {
return
}
for _, key := range keys {
m.bloomf.Add([]byte(key))
}
return
}
if err := init(); err != nil {
logger.Printf(logger.ERROR, "[revocation] Failed to initialize module: %s\n", err.Error())
return nil
}
// register as listener for core events
listener := m.Run(ctx, m.event, m.Filter(), 0, nil)
c.Register("gns", listener)
return m
}
//----------------------------------------------------------------------
// Filter returns the event filter for the service
func (m *Module) Filter() *core.EventFilter {
f := core.NewEventFilter()
f.AddMsgType(enums.MSG_REVOCATION_QUERY)
f.AddMsgType(enums.MSG_REVOCATION_QUERY_RESPONSE)
f.AddMsgType(enums.MSG_REVOCATION_REVOKE)
f.AddMsgType(enums.MSG_REVOCATION_REVOKE_RESPONSE)
return f
}
// Event handler
func (m *Module) event(ctx context.Context, ev *core.Event) {
}
//----------------------------------------------------------------------
// Export functions
func (m *Module) Export(fcn map[string]any) {
// add exported functions from module
fcn["rev:query"] = m.Query
fcn["rev:revoke"] = m.Revoke
}
// Import functions
func (m *Module) Import(fcm map[string]any) {
// nothing to import now.
}
//----------------------------------------------------------------------
// Query return true if the pkey is valid (not revoked) and false
// if the pkey has been revoked ["rev:query"]
func (m *Module) Query(ctx context.Context, zkey *crypto.ZoneKey) (valid bool, err error) {
// fast check first: is the key in the bloomfilter?
data := zkey.Bytes()
if !m.bloomf.Contains(data) {
// no: it is valid (not revoked)
return true, nil
}
// check in store to detect false-positives
key := util.EncodeBinaryToString(data)
if _, err = m.kvs.Get(key); err != nil {
logger.Printf(logger.ERROR, "[revocation] Failed to locate key '%s' in store: %s\n", key, err.Error())
// assume not revoked...
return true, err
}
// key seems to be revoked
return false, nil
}
// Revoke a key with given revocation data ["rev:revoke"]
func (m *Module) Revoke(ctx context.Context, rd *RevData) (success bool, err error) {
// verify the revocation data
diff, rc := rd.Verify(true)
switch {
case rc == -1:
logger.Println(logger.WARN, "[revocation] Revoke: Missing/invalid signature")
return false, nil
case rc == -2:
logger.Println(logger.WARN, "[revocation] Revoke: Expired revocation")
return false, nil
case rc == -3:
logger.Println(logger.WARN, "[revocation] Revoke: Wrong PoW sequence order")
return false, nil
}
if diff < float64(MinAvgDifficulty) {
logger.Println(logger.WARN, "[revocation] Revoke: Difficulty to small")
return false, nil
}
// store the revocation data
// (1) add it to the bloomfilter
m.bloomf.Add(rd.ZoneKeySig.KeyData)
// (2) add it to the store
var buf []byte
if buf, err = data.Marshal(rd); err != nil {
return false, err
}
value := util.EncodeBinaryToString(buf)
err = m.kvs.Put(rd.ZoneKeySig.ID(), value)
return true, err
}
//----------------------------------------------------------------------
// RPC returns the route and handler function for a JSON-RPC request
func (m *Module) RPC() (string, func(http.ResponseWriter, *http.Request)) {
return "/revocation/", func(wrt http.ResponseWriter, req *http.Request) {
_, _ = wrt.Write([]byte(`{"msg": "This is REVOCATION" }`))
}
}
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