mirror of
https://github.com/strukturag/nextcloud-spreed-signaling.git
synced 2024-11-21 07:07:58 +00:00
9aeb57d74e
This will reduce their size and improve encoding / decoding performance. Also fixes GO-2024-3106 (Stack exhaustion in Decoder.Decode in encoding/gob).
122 lines
3.3 KiB
Go
122 lines
3.3 KiB
Go
/**
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* Standalone signaling server for the Nextcloud Spreed app.
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* Copyright (C) 2024 struktur AG
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*
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* @author Joachim Bauch <bauch@struktur.de>
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*
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* @license GNU AGPL version 3 or any later version
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package signaling
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import (
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"encoding/base64"
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"fmt"
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"github.com/gorilla/securecookie"
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"google.golang.org/protobuf/proto"
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)
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type protoSerializer struct {
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}
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func (s *protoSerializer) Serialize(src interface{}) ([]byte, error) {
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msg, ok := src.(proto.Message)
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if !ok {
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return nil, fmt.Errorf("can't serialize type %T", src)
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}
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return proto.Marshal(msg)
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}
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func (s *protoSerializer) Deserialize(src []byte, dst interface{}) error {
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msg, ok := dst.(proto.Message)
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if !ok {
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return fmt.Errorf("can't deserialize type %T", src)
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}
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return proto.Unmarshal(src, msg)
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}
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const (
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privateSessionName = "private-session"
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publicSessionName = "public-session"
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)
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type SessionIdCodec struct {
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cookie *securecookie.SecureCookie
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}
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func NewSessionIdCodec(hashKey []byte, blockKey []byte) *SessionIdCodec {
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cookie := securecookie.New(hashKey, blockKey).
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MaxAge(0).
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SetSerializer(&protoSerializer{})
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return &SessionIdCodec{
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cookie: cookie,
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}
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}
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func (c *SessionIdCodec) EncodePrivate(sessionData *SessionIdData) (string, error) {
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return c.cookie.Encode(privateSessionName, sessionData)
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}
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func reverseSessionId(s string) (string, error) {
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// Note that we are assuming base64 encoded strings here.
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decoded, err := base64.URLEncoding.DecodeString(s)
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if err != nil {
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return "", err
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}
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for i, j := 0, len(decoded)-1; i < j; i, j = i+1, j-1 {
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decoded[i], decoded[j] = decoded[j], decoded[i]
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}
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return base64.URLEncoding.EncodeToString(decoded), nil
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}
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func (c *SessionIdCodec) EncodePublic(sessionData *SessionIdData) (string, error) {
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encoded, err := c.cookie.Encode(publicSessionName, sessionData)
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if err != nil {
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return "", err
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}
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// We are reversing the public session ids because clients compare them
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// to decide who calls whom. The prefix of the session id is increasing
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// (a timestamp) but the suffix the (random) hash.
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// By reversing we move the hash to the front, making the comparison of
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// session ids "random".
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return reverseSessionId(encoded)
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}
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func (c *SessionIdCodec) DecodePrivate(encodedData string) (*SessionIdData, error) {
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var data SessionIdData
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if err := c.cookie.Decode(privateSessionName, encodedData, &data); err != nil {
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return nil, err
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}
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return &data, nil
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}
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func (c *SessionIdCodec) DecodePublic(encodedData string) (*SessionIdData, error) {
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encodedData, err := reverseSessionId(encodedData)
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if err != nil {
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return nil, err
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}
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var data SessionIdData
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if err := c.cookie.Decode(publicSessionName, encodedData, &data); err != nil {
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return nil, err
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}
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return &data, nil
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}
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