ooni-probe-cli/internal/engine/session_psiphon.go
Simone Basso a849213b59
fix(engine): break circular dep betwen session and tunnel (#295)
This diff breaks the circular dependency between session and
tunnel, by introducing the concept of early session.

An early session is a session that is able to fetch the psiphon
configuration file _only_ if it's embedded in the binary.

This breaks `miniooni --tunnel=psiphon` for users who have
access to the OONI backend. They are not the users we are
writing this feature for, though, so I think this is reasonable.

At the same time, this opens up the possibility of creating
a psiphon tunnel when constructing a session, which is the
approach I was following in https://github.com/ooni/probe-cli/pull/286.

This work is part of https://github.com/ooni/probe/issues/985.

Once this diff is in, I can land https://github.com/ooni/probe-cli/pull/286.
2021-04-05 12:02:35 +02:00

46 lines
1.1 KiB
Go

// +build ooni_psiphon_config
package engine
import (
"bytes"
"context"
_ "embed"
"io/ioutil"
"filippo.io/age"
)
//go:embed psiphon-config.json.age
var psiphonConfigJSONAge []byte
//go:embed psiphon-config.key
var psiphonConfigSecretKey string
// sessionTunnelEarlySession is the early session that we pass
// to tunnel.Start to fetch the Psiphon configuration.
type sessionTunnelEarlySession struct{}
// FetchPsiphonConfig decrypts psiphonConfigJSONAge using
// filippo.io/age _and_ psiphonConfigSecretKey.
func (s *sessionTunnelEarlySession) FetchPsiphonConfig(ctx context.Context) ([]byte, error) {
key := "AGE-SECRET-KEY-1" + psiphonConfigSecretKey
identity, err := age.ParseX25519Identity(key)
if err != nil {
return nil, err
}
input := bytes.NewReader(psiphonConfigJSONAge)
output, err := age.Decrypt(input, identity)
if err != nil {
return nil, err
}
return ioutil.ReadAll(output)
}
// FetchPsiphonConfig decrypts psiphonConfigJSONAge using
// filippo.io/age _and_ psiphonConfigSecretKey.
func (s *Session) FetchPsiphonConfig(ctx context.Context) ([]byte, error) {
child := &sessionTunnelEarlySession{}
return child.FetchPsiphonConfig(ctx)
}