1 files changed, 124 insertions, 0 deletions

diff --git a/src/gnunet/service/revocation/module.go b/src/gnunet/service/revocation/module.go
new file mode 100644
index 0000000..b5c8a16
--- /dev/null
+++ b/src/gnunet/service/revocation/module.go
@@ -0,0 +1,124 @@
+// This file is part of gnunet-go, a GNUnet-implementation in Golang.
+// Copyright (C) 2019, 2020 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 (
+        "gnunet/config"
+        "gnunet/service"
+        "gnunet/util"
+
+        "github.com/bfix/gospel/crypto/ed25519"
+        "github.com/bfix/gospel/data"
+        "github.com/bfix/gospel/logger"
+)
+
+//======================================================================
+// "GNUnet Revocation" implementation
+//======================================================================
+
+// RevocationModule handles the revocation-related calls to other modules.
+type RevocationModule struct {
+        bloomf *data.BloomFilter  // bloomfilter for fast revocation check
+        kvs    util.KeyValueStore // storage for known revocations
+}
+
+// Init a revocation module
+func (m *RevocationModule) Init() error {
+        // Initialize access to revocation data storage
+        var err error
+        if m.kvs, err = util.OpenKVStore(config.Cfg.Revocation.Storage); err != nil {
+                return err
+        }
+        // traverse the storage and build bloomfilter for all keys
+        m.bloomf = data.NewBloomFilter(1000000, 1e-8)
+        keys, err := m.kvs.List()
+        if err != nil {
+                return err
+        }
+        for _, key := range keys {
+                buf, err := util.DecodeStringToBinary(key, 32)
+                if err != nil {
+                        return err
+                }
+                m.bloomf.Add(buf)
+        }
+        return nil
+}
+
+// NewRevocationModule returns an initialized revocation module
+func NewRevocationModule() *RevocationModule {
+        m := new(RevocationModule)
+        if err := m.Init(); err != nil {
+                logger.Printf(logger.ERROR, "[revocation] Failed to initialize module: %s\n", err.Error())
+                return nil
+        }
+        return m
+}
+
+// Query return true if the pkey is valid (not revoked) and false
+// if the pkey has been revoked.
+func (s *RevocationModule) Query(ctx *service.SessionContext, pkey *ed25519.PublicKey) (valid bool, err error) {
+        // fast check first: is the key in the bloomfilter?
+        data := pkey.Bytes()
+        if !s.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 = s.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
+func (s *RevocationModule) Revoke(ctx *service.SessionContext, rd *RevData) (success bool, err error) {
+        // verify the revocation data
+        rc := rd.Verify()
+        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
+        case rc < 25:
+                logger.Println(logger.WARN, "[revocation] Revoke: Difficulty to small")
+                return false, nil
+        }
+        // store the revocation data
+        // (1) add it to the bloomfilter
+        s.bloomf.Add(rd.ZoneKey)
+        // (2) add it to the store
+        var buf []byte
+        key := util.EncodeBinaryToString(rd.ZoneKey)
+        if buf, err = data.Marshal(rd); err != nil {
+                return false, err
+        }
+        value := util.EncodeBinaryToString(buf)
+        err = s.kvs.Put(key, value)
+        return true, err
+}