[tor-commits] [pluggable-transports/snowflake] 02/03: Forward bridge fingerprint
gitolite role
git at cupani.torproject.org
Mon Mar 21 19:37:17 UTC 2022
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arlo pushed a commit to branch main
in repository pluggable-transports/snowflake.
commit b563141c6abba128386bc1ad18122d5e13e09789
Author: Arlo Breault <arlolra at gmail.com>
AuthorDate: Tue Mar 8 16:27:52 2022 -0500
Forward bridge fingerprint
gitlab 28651
---
broker/broker.go | 7 ++++---
broker/ipc.go | 5 +++--
client/lib/rendezvous.go | 7 +++++--
client/lib/snowflake.go | 3 +++
client/snowflake.go | 3 +++
client/torrc | 2 +-
common/messages/client.go | 25 ++++++++++++++++++++++---
7 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/broker/broker.go b/broker/broker.go
index 7a29265..6e85fbd 100644
--- a/broker/broker.go
+++ b/broker/broker.go
@@ -139,10 +139,11 @@ func (ctx *BrokerContext) AddSnowflake(id string, proxyType string, natType stri
return snowflake
}
-// Client offer contains an SDP and the NAT type of the client
+// Client offer contains an SDP, bridge fingerprint and the NAT type of the client
type ClientOffer struct {
- natType string
- sdp []byte
+ natType string
+ sdp []byte
+ fingerprint string
}
func main() {
diff --git a/broker/ipc.go b/broker/ipc.go
index 5cc595b..2ef4ccd 100644
--- a/broker/ipc.go
+++ b/broker/ipc.go
@@ -130,8 +130,9 @@ func (i *IPC) ClientOffers(arg messages.Arg, response *[]byte) error {
}
offer := &ClientOffer{
- natType: req.NAT,
- sdp: []byte(req.Offer),
+ natType: req.NAT,
+ sdp: []byte(req.Offer),
+ fingerprint: req.Fingerprint,
}
// Only hand out known restricted snowflakes to unrestricted clients
diff --git a/client/lib/rendezvous.go b/client/lib/rendezvous.go
index d908b77..38e4620 100644
--- a/client/lib/rendezvous.go
+++ b/client/lib/rendezvous.go
@@ -43,6 +43,7 @@ type BrokerChannel struct {
keepLocalAddresses bool
natType string
lock sync.Mutex
+ BridgeFingerprint string
}
// We make a copy of DefaultTransport because we want the default Dial
@@ -92,6 +93,7 @@ func newBrokerChannelFromConfig(config ClientConfig) (*BrokerChannel, error) {
Rendezvous: rendezvous,
keepLocalAddresses: config.KeepLocalAddresses,
natType: nat.NATUnknown,
+ BridgeFingerprint: config.BridgeFingerprint,
}, nil
}
@@ -116,8 +118,9 @@ func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) (
// Encode the client poll request.
bc.lock.Lock()
req := &messages.ClientPollRequest{
- Offer: offerSDP,
- NAT: bc.natType,
+ Offer: offerSDP,
+ NAT: bc.natType,
+ Fingerprint: bc.BridgeFingerprint,
}
encReq, err := req.EncodeClientPollRequest()
bc.lock.Unlock()
diff --git a/client/lib/snowflake.go b/client/lib/snowflake.go
index 1b236a6..dd78c12 100644
--- a/client/lib/snowflake.go
+++ b/client/lib/snowflake.go
@@ -103,6 +103,9 @@ type ClientConfig struct {
// UTLSRemoveSNI is the flag to control whether SNI should be removed from Client Hello
// when uTLS is used.
UTLSRemoveSNI bool
+ // BridgeFingerprint is the fingerprint of the bridge that the client will eventually
+ // connect to, as specified in the Bridge line of the torrc.
+ BridgeFingerprint string
}
// NewSnowflakeClient creates a new Snowflake transport client that can spawn multiple
diff --git a/client/snowflake.go b/client/snowflake.go
index 5856750..33834ad 100644
--- a/client/snowflake.go
+++ b/client/snowflake.go
@@ -95,6 +95,9 @@ func socksAcceptLoop(ln *pt.SocksListener, config sf.ClientConfig, shutdown chan
if arg, ok := conn.Req.Args.Get("utls-imitate"); ok {
config.UTLSClientID = arg
}
+ if arg, ok := conn.Req.Args.Get("fingerprint"); ok {
+ config.BridgeFingerprint = arg
+ }
transport, err := sf.NewSnowflakeClient(config)
if err != nil {
conn.Reject()
diff --git a/client/torrc b/client/torrc
index 039653f..aee4df1 100644
--- a/client/torrc
+++ b/client/torrc
@@ -3,6 +3,6 @@ DataDirectory datadir
ClientTransportPlugin snowflake exec ./client -log snowflake.log
-Bridge snowflake 192.0.2.3:1 url=https://snowflake-broker.torproject.net.global.prod.fastly.net/ front=cdn.sstatic.net ice=stun:stun.voip.blackberry.com:3478,stun:stun.altar.com.pl:3478,stun:stun.antisip.com:3478,stun:stun.bluesip.net:3478,stun:stun.dus.net:3478,stun:stun.epygi.com:3478,stun:stun.sonetel.com:3478,stun:stun.sonetel.net:3478,stun:stun.stunprotocol.org:3478,stun:stun.uls.co.za:3478,stun:stun.voipgate.com:3478,stun:stun.voys.nl:3478
+Bridge snowflake 192.0.2.3:1 2B280B23E1107BB62ABFC40DDCC8824814F80A72 fingerprint=2B280B23E1107BB62ABFC40DDCC8824814F80A72 url=https://snowflake-broker.torproject.net.global.prod.fastly.net/ front=cdn.sstatic.net ice=stun:stun.voip.blackberry.com:3478,stun:stun.altar.com.pl:3478,stun:stun.antisip.com:3478,stun:stun.bluesip.net:3478,stun:stun.dus.net:3478,stun:stun.epygi.com:3478,stun:stun.sonetel.com:3478,stun:stun.sonetel.net:3478,stun:stun.stunprotocol.org:3478,stun:stun.uls.co.za:3478 [...]
SocksPort auto
diff --git a/common/messages/client.go b/common/messages/client.go
index b6155f7..4d435ab 100644
--- a/common/messages/client.go
+++ b/common/messages/client.go
@@ -29,10 +29,13 @@ each encoded in JSON format
{
offer: <sdp offer>
[nat: (unknown|restricted|unrestricted)]
+ [fingerprint: <fingerprint string>]
}
The NAT field is optional, and if it is missing a
-value of "unknown" will be assumed.
+value of "unknown" will be assumed. The fingerprint
+is also optional and, if absent, will be assigned the
+fingerprint of the default bridge.
== ClientPollResponse ==
<poll response> :=
@@ -49,13 +52,25 @@ for the error.
*/
+// The bridge fingerprint to assume, for client poll requests that do not
+// specify a fingerprint. Before #28651, there was only one bridge with one
+// fingerprint, which all clients expected to be connected to implicitly.
+// If a client is old enough that it does not specify a fingerprint, this is
+// the fingerprint it expects. Clients that do set a fingerprint in the
+// SOCKS params will also be assumed to want to connect to the default bridge.
+const defaultBridgeFingerprint = "2B280B23E1107BB62ABFC40DDCC8824814F80A72"
+
type ClientPollRequest struct {
- Offer string `json:"offer"`
- NAT string `json:"nat"`
+ Offer string `json:"offer"`
+ NAT string `json:"nat"`
+ Fingerprint string `json:"fingerprint"`
}
// Encodes a poll message from a snowflake client
func (req *ClientPollRequest) EncodeClientPollRequest() ([]byte, error) {
+ if req.Fingerprint == "" {
+ req.Fingerprint = defaultBridgeFingerprint
+ }
body, err := json.Marshal(req)
if err != nil {
return nil, err
@@ -87,6 +102,10 @@ func DecodeClientPollRequest(data []byte) (*ClientPollRequest, error) {
return nil, fmt.Errorf("no supplied offer")
}
+ if message.Fingerprint == "" {
+ message.Fingerprint = defaultBridgeFingerprint
+ }
+
switch message.NAT {
case "":
message.NAT = nat.NATUnknown
--
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