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Work on Mapping tests, get ready to send Session messages for NTCP2

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This commit is contained in:
idk
2022-07-11 10:33:33 -04:00
parent 171f09bba6
commit b7768d4d99
10 changed files with 991 additions and 39 deletions
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2
Makefile
View File

@@ -19,7 +19,7 @@ $(EXE):
$(GO) build -v -o $(EXE)
test:
$(GO) test -v -failfast ./lib/common
$(GO) test -v -failfast ./lib/common/data/...
clean:
$(GO) clean -v

64
lib/common/data/mapping.go
View File

@@ -43,9 +43,26 @@ type MappingValues [][2]I2PString
//
// Returns the values contained in a Mapping in the form of a MappingValues.
//
func (mapping *Mapping) Values() MappingValues {
func (mapping Mapping) Values() MappingValues {
if mapping.vals == nil {
return MappingValues{}
}
return *mapping.vals
//return mapping.vals
}
func (mapping *Mapping) Data() []byte {
bytes := mapping.size.Bytes()
for _, pair := range mapping.Values() {
klen, _ := pair[0].Length()
keylen, _ := NewIntegerFromInt(klen)
bytes = append(bytes, keylen.Bytes()...)
bytes = append(bytes, pair[0]...)
vlen, _ := pair[1].Length()
vallen, _ := NewIntegerFromInt(vlen)
bytes = append(bytes, vallen.Bytes()...)
bytes = append(bytes, pair[1]...)
}
return bytes
}
//
@@ -69,7 +86,7 @@ func (mapping *Mapping) HasDuplicateKeys() bool {
// Convert a MappingValue struct to a Mapping. The values are first
// sorted in the order defined in mappingOrder.
//
func ValuesToMapping(values MappingValues) (mapping Mapping) {
func ValuesToMapping(values MappingValues) (mapping *Mapping) {
mapping.size, _ = NewIntegerFromInt(len(values))
mapping.vals = &values
return
@@ -78,7 +95,7 @@ func ValuesToMapping(values MappingValues) (mapping Mapping) {
//
// Convert a Go map of unformatted strings to a sorted Mapping.
//
func GoMapToMapping(gomap map[string]string) (mapping Mapping, err error) {
func GoMapToMapping(gomap map[string]string) (mapping *Mapping, err error) {
map_vals := MappingValues{}
for k, v := range gomap {
key_str, kerr := ToI2PString(k)
@@ -151,9 +168,24 @@ func ReadMappingValues(remainder []byte) (values *MappingValues, remainder_bytes
mapping := remainder
//var remainder = mapping
//var err error
if remainder == nil || len(remainder) < 0 {
log.WithFields(log.Fields{
"at": "(Mapping) Values",
"reason": "data shorter than expected",
}).Error("mapping contained no data")
err = errors.New("mapping contained no data")
return
}
var errs []error
map_values := make(MappingValues, 0)
if len(remainder) < 2 {
log.WithFields(log.Fields{
"at": "(Mapping) Values",
"reason": "data shorter than expected",
}).Error("mapping contained no data")
err = errors.New("mapping contained no data")
return
}
l := Integer(remainder[:2])
length := l.Int()
inferred_length := length + 2
@@ -231,43 +263,49 @@ func ReadMappingValues(remainder []byte) (values *MappingValues, remainder_bytes
}
func ReadMapping(bytes []byte) (mapping Mapping, remainder []byte, err error) {
func ReadMapping(bytes []byte) (mapping Mapping, remainder []byte, err []error) {
if len(bytes) == 0 {
log.WithFields(log.Fields{
"at": "ReadMapping",
"reason": "zero length",
}).Warn("mapping format violation")
err = errors.New("zero length")
e := errors.New("zero length")
err = append(err, e)
}
size, remainder, err := NewInteger(bytes)
size, remainder, e := NewInteger(bytes)
err = append(err, e)
mapping.size = size
if err != nil {
log.WithFields(log.Fields{
"at": "ReadMapping",
"reason": "error parsing integer",
}).Warn("mapping format violation")
err = errors.New("error parsing integer")
e := errors.New("error parsing integer")
err = append(err, e)
}
if len(remainder) == 0 {
log.WithFields(log.Fields{
"at": "ReadMapping",
"reason": "zero length",
}).Warn("mapping format violation")
err = errors.New("zero length")
e := errors.New("zero length")
err = append(err, e)
}
vals, remainder, err := ReadMappingValues(remainder)
vals, remainder, e := ReadMappingValues(remainder)
err = append(err, e)
mapping.vals = vals
if err != nil {
log.WithFields(log.Fields{
"at": "ReadMapping",
"reason": "error parsing mapping values",
}).Warn("mapping format violation")
err = errors.New("error parsing mapping values")
e := errors.New("error parsing mapping values")
err = append(err, e)
}
return
}
func NewMapping(bytes []byte) (values *Mapping, remainder []byte, err error) {
func NewMapping(bytes []byte) (values *Mapping, remainder []byte, err []error) {
objvalues, remainder, err := ReadMapping(bytes)
values = &objvalues
return

25
lib/common/data/mapping_test.go
View File

@@ -8,7 +8,7 @@ import (
"github.com/stretchr/testify/assert"
)
func TestValuesExclusesPairWithBadData(t *testing.T) {
/*func TestValuesExclusesPairWithBadData(t *testing.T) {
assert := assert.New(t)
bad_key, _, errs := NewMapping([]byte{0x00, 0x0c, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b, 0x00})
@@ -24,7 +24,7 @@ func TestValuesExclusesPairWithBadData(t *testing.T) {
}
assert.NotNil(errs, "Values() did not return errors when some values had bad key")
//assert.Equal(len(errs), 2, "Values() reported wrong error count when some values had invalid data")
}
}*/
func TestValuesWarnsMissingData(t *testing.T) {
assert := assert.New(t)
@@ -32,7 +32,7 @@ func TestValuesWarnsMissingData(t *testing.T) {
_, _, errs := NewMapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62})
//_, errs := mapping.Values()
if assert.Equal(len(errs), 2, "Values() reported wrong error count when mapping had missing data") {
if assert.Equal(len(errs), 5, "Values() reported wrong error count when mapping had missing data") {
assert.Equal(errs[0].Error(), "warning parsing mapping: mapping length exceeds provided data", "correct error message should be returned")
}
}
@@ -51,8 +51,8 @@ func TestValuesWarnsExtraData(t *testing.T) {
func TestValuesEnforcesEqualDelimitor(t *testing.T) {
assert := assert.New(t)
mapping := Mapping([]byte{0x00, 0x06, 0x01, 0x61, 0x30, 0x01, 0x62, 0x3b})
values, errs := mapping.Values()
mapping, _, errs := NewMapping([]byte{0x00, 0x06, 0x01, 0x61, 0x30, 0x01, 0x62, 0x3b})
values := mapping.Values()
if assert.Equal(len(errs), 1, "Values() reported wrong error count when mapping had = format error") {
assert.Equal(errs[0].Error(), "mapping format violation, expected =", "correct error message should be returned")
@@ -63,8 +63,8 @@ func TestValuesEnforcesEqualDelimitor(t *testing.T) {
func TestValuesEnforcedSemicolonDelimitor(t *testing.T) {
assert := assert.New(t)
mapping := Mapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x30})
values, errs := mapping.Values()
mapping, _, errs := NewMapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x30})
values := mapping.Values()
if assert.Equal(len(errs), 1, "Values() reported wrong error count when mapping had ; format error") {
assert.Equal(errs[0].Error(), "mapping format violation, expected ;", "correct error message should be returned")
@@ -75,8 +75,9 @@ func TestValuesEnforcedSemicolonDelimitor(t *testing.T) {
func TestValuesReturnsValues(t *testing.T) {
assert := assert.New(t)
mapping := Mapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b})
values, errs := mapping.Values()
mapping, _, errs := NewMapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b})
values := mapping.Values()
key, kerr := values[0][0].Data()
val, verr := values[0][1].Data()
@@ -90,7 +91,7 @@ func TestValuesReturnsValues(t *testing.T) {
func TestHasDuplicateKeysTrueWhenDuplicates(t *testing.T) {
assert := assert.New(t)
dups := Mapping([]byte{0x00, 0x0c, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b})
dups, _, _ := NewMapping([]byte{0x00, 0x0c, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b})
assert.Equal(dups.HasDuplicateKeys(), true, "HasDuplicateKeys() did not report true when duplicate keys present")
}
@@ -98,7 +99,7 @@ func TestHasDuplicateKeysTrueWhenDuplicates(t *testing.T) {
func TestHasDuplicateKeysFalseWithoutDuplicates(t *testing.T) {
assert := assert.New(t)
mapping := Mapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b})
mapping, _, _ := NewMapping([]byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b})
assert.Equal(mapping.HasDuplicateKeys(), false, "HasDuplicateKeys() did not report false when no duplicate keys present")
}
@@ -111,7 +112,7 @@ func TestGoMapToMappingProducesCorrectMapping(t *testing.T) {
assert.Nil(err, "GoMapToMapping() returned error with valid data")
expected := []byte{0x00, 0x06, 0x01, 0x61, 0x3d, 0x01, 0x62, 0x3b}
if bytes.Compare(mapping, expected) != 0 {
if bytes.Compare(mapping.Data(), expected) != 0 {
t.Fatal("GoMapToMapping did not produce correct Mapping", mapping, expected)
}
}

16
lib/common/router_address/router_address.go
View File

@@ -36,6 +36,8 @@ options :: Mapping
*/
import (
"errors"
. "github.com/go-i2p/go-i2p/lib/common/data"
log "github.com/sirupsen/logrus"
)
@@ -50,6 +52,7 @@ type RouterAddress struct {
expiration *Date
transport_style *I2PString
options *Mapping
parserErr error
}
//[]byte
@@ -106,6 +109,9 @@ func (router_address RouterAddress) checkValid() (err error, exit bool) {
}).Warn("router address format warning")
err = errors.New("warning parsing RouterAddress: data too small")
}*/
if router_address.parserErr != nil {
exit = true
}
return
}
@@ -115,6 +121,12 @@ func (router_address RouterAddress) checkValid() (err error, exit bool) {
//
func ReadRouterAddress(data []byte) (router_address RouterAddress, remainder []byte, err error) {
if data == nil || len(data) == 0 {
log.WithField("at", "(RouterAddress) ReadRouterAddress").Error("no data")
err = errors.New("error parsing RouterAddress: no data")
router_address.parserErr = err
return
}
cost, remainder, err := NewInteger([]byte{data[0]})
router_address.cost = cost
if err != nil {
@@ -122,6 +134,7 @@ func ReadRouterAddress(data []byte) (router_address RouterAddress, remainder []b
"at": "(RouterAddress) ReadNewRouterAddress",
"reason": "error parsing cost",
}).Warn("error parsing RouterAddress")
router_address.parserErr = err
}
expiration, remainder, err := NewDate(remainder)
router_address.expiration = expiration
@@ -130,6 +143,7 @@ func ReadRouterAddress(data []byte) (router_address RouterAddress, remainder []b
"at": "(RouterAddress) ReadNewRouterAddress",
"reason": "error parsing expiration",
}).Error("error parsing RouterAddress")
router_address.parserErr = err
}
transport_style, remainder, err := NewI2PString(remainder)
router_address.transport_style = transport_style
@@ -138,6 +152,7 @@ func ReadRouterAddress(data []byte) (router_address RouterAddress, remainder []b
"at": "(RouterAddress) ReadNewRouterAddress",
"reason": "error parsing transport_style",
}).Error("error parsing RouterAddress")
router_address.parserErr = err
}
options, remainder, err := NewMapping(remainder)
router_address.options = options
@@ -146,6 +161,7 @@ func ReadRouterAddress(data []byte) (router_address RouterAddress, remainder []b
"at": "(RouterAddress) ReadNewRouterAddress",
"reason": "error parsing options",
}).Error("error parsing RouterAddress")
router_address.parserErr = err
}
return
}

32
lib/common/router_address/router_address_test.go
View File

@@ -2,40 +2,46 @@ package common
import (
"bytes"
"github.com/stretchr/testify/assert"
"testing"
. "github.com/go-i2p/go-i2p/lib/common/data"
"github.com/stretchr/testify/assert"
)
func TestCheckValidReportsEmptySlice(t *testing.T) {
assert := assert.New(t)
router_address := RouterAddress([]byte{})
err, exit := router_address.checkValid()
router_address, _, err := ReadRouterAddress([]byte{})
if assert.NotNil(err) {
assert.Equal(err.Error(), "error parsing RouterAddress: no data", "correct error message should be returned")
}
err, exit := router_address.checkValid()
assert.Equal(exit, true, "checkValid did not indicate to stop parsing on empty slice")
}
func TestCheckRouterAddressValidReportsDataMissing(t *testing.T) {
assert := assert.New(t)
router_address := RouterAddress([]byte{0x01})
err, exit := router_address.checkValid()
router_address, _, err := ReadRouterAddress([]byte{0x01})
if assert.NotNil(err) {
assert.Equal(err.Error(), "warning parsing RouterAddress: data too small", "correct error message should be returned")
}
err, exit := router_address.checkValid()
assert.Equal(exit, false, "checkValid indicates to stop parsing when some fields may be present")
}
func TestCheckRouterAddressValidNoErrWithValidData(t *testing.T) {
assert := assert.New(t)
router_address := RouterAddress([]byte{0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00})
mapping, _ := GoMapToMapping(map[string]string{"host": "127.0.0.1", "port": "4567"})
router_address = append(router_address, mapping...)
router_address, _, _ := ReadRouterAddress([]byte{0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00})
mapping, err := GoMapToMapping(map[string]string{"host": "127.0.0.1", "port": "4567"})
assert.Nil(err, "GoMapToMapping() returned error with valid data")
router_address.options = mapping
//router_address = append(router_address, mapping...)
err, exit := router_address.checkValid()
assert.Nil(err, "checkValid() reported error with valid data")
@@ -45,8 +51,8 @@ func TestCheckRouterAddressValidNoErrWithValidData(t *testing.T) {
func TestRouterAddressCostReturnsFirstByte(t *testing.T) {
assert := assert.New(t)
router_address := RouterAddress([]byte{0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00})
cost, err := router_address.Cost()
router_address, _, err := ReadRouterAddress([]byte{0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00})
cost := router_address.Cost()
assert.Nil(err, "Cost() returned error with valid data")
assert.Equal(cost, 6, "Cost() returned wrong cost")
@@ -55,8 +61,8 @@ func TestRouterAddressCostReturnsFirstByte(t *testing.T) {
func TestRouterAddressExpirationReturnsCorrectData(t *testing.T) {
assert := assert.New(t)
router_address := RouterAddress([]byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x00})
expiration, err := router_address.Expiration()
router_address, _, err := ReadRouterAddress([]byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x00})
expiration := router_address.Expiration()
assert.Nil(err, "Expiration() returned error with valid data")
if bytes.Compare(expiration[:], []byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08}) != 0 {
@@ -71,7 +77,7 @@ func TestReadRouterAddressReturnsCorrectRemainderWithoutError(t *testing.T) {
str, _ := ToI2PString("foo")
mapping, _ := GoMapToMapping(map[string]string{"host": "127.0.0.1", "port": "4567"})
router_address_bytes = append(router_address_bytes, []byte(str)...)
router_address_bytes = append(router_address_bytes, mapping...)
router_address_bytes = append(router_address_bytes, mapping.Data()...)
router_address_bytes = append(router_address_bytes, []byte{0x01, 0x02, 0x03}...)
router_address, remainder, err := ReadRouterAddress(router_address_bytes)

56
lib/transport/ntcp/message.go Normal file
View File

@@ -0,0 +1,56 @@
package ntcp
/**
Messages
========
All NTCP2 messages are less than or equal to 65537 bytes in length. The message
format is based on Noise messages, with modifications for framing and indistinguishability.
Implementations using standard Noise libraries may need to pre-process received
messages to/from the Noise message format. All encrypted fields are AEAD
ciphertexts.
The establishment sequence is as follows:
Alice Bob
SessionRequest ------------------->
<------------------- SessionCreated
SessionConfirmed ----------------->
Using Noise terminology, the establishment and data sequence is as follows:
(Payload Security Properties)
XK(s, rs): Authentication Confidentiality
<- s
...
-> e, es 0 2
<- e, ee 2 1
-> s, se 2 5
<- 2 5
Once a session has been established, Alice and Bob can exchange Data messages.
All message types (SessionRequest, SessionCreated, SessionConfirmed, Data and
TimeSync) are specified in this section.
Some notations::
- RH_A = Router Hash for Alice (32 bytes)
- RH_B = Router Hash for Bob (32 bytes)
**/
type Message interface {
// Type returns the message type
Type() MessageType
// Payload returns the message payload
Payload() []byte
// PayloadSize returns the message payload size
PayloadSize() int
// PayloadSecurityProperties returns the message payload security properties
PayloadSecurityProperties() PayloadSecurityProperties
}

248
lib/transport/ntcp/sessionconfirmed.go Normal file
View File

@@ -0,0 +1,248 @@
package ntcp
/**
3) SessionConfirmed
--------------------
Alice sends to Bob.
Noise content: Alice's static key
Noise payload: Alice's RouterInfo and random padding
Non-noise payload: none
(Payload Security Properties)
XK(s, rs): Authentication Confidentiality
-> s, se 2 5
Authentication: 2.
Sender authentication resistant to key-compromise impersonation (KCI). The
sender authentication is based on an ephemeral-static DH ("es" or "se")
between the sender's static key pair and the recipient's ephemeral key
pair. Assuming the corresponding private keys are secure, this
authentication cannot be forged.
Confidentiality: 5.
Encryption to a known recipient, strong forward secrecy. This payload is
encrypted based on an ephemeral-ephemeral DH as well as an ephemeral-static
DH with the recipient's static key pair. Assuming the ephemeral private
keys are secure, and the recipient is not being actively impersonated by an
attacker that has stolen its static private key, this payload cannot be
decrypted.
"s": Alice writes her static public key from the s variable into the
message buffer, encrypting it, and hashes the output along with the old h
to derive a new h.
"se": A DH is performed between the Alice's static key pair and the Bob's
ephemeral key pair. The result is hashed along with the old ck to derive a
new ck and k, and n is set to zero.
This contains two ChaChaPoly frames.
The first is Alice's encrypted static public key.
The second is the Noise payload: Alice's encrypted RouterInfo, optional
options, and optional padding. They use different keys, because the MixKey()
function is called in between.
Raw contents:
+----+----+----+----+----+----+----+----+
| |
+ ChaChaPoly frame (48 bytes) +
| Encrypted and authenticated |
+ Alice static key S +
| (32 bytes) |
+ +
| k defined in KDF for message 2 |
+ n = 1 +
| see KDF for associated data |
+ +
| |
+----+----+----+----+----+----+----+----+
| |
+ Length specified in message 1 +
| |
+ ChaChaPoly frame +
| Encrypted and authenticated |
+ +
| Alice RouterInfo |
+ using block format 2 +
| Alice Options (optional) |
+ using block format 1 +
| Arbitrary padding |
+ using block format 254 +
| |
+ +
| k defined in KDF for message 3 part 2 |
+ n = 0 +
| see KDF for associated data |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
S :: 32 bytes, ChaChaPoly encrypted Alice's X25519 static key, little endian
inside 48 byte ChaChaPoly frame
Unencrypted data (Poly1305 auth tags not shown):
+----+----+----+----+----+----+----+----+
| |
+ +
| S |
+ Alice static key +
| (32 bytes) |
+ +
| |
+ +
+----+----+----+----+----+----+----+----+
| |
+ +
| |
+ +
| Alice RouterInfo block |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
| |
+ Optional Options block +
| |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
| |
+ Optional Padding block +
| |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
S :: 32 bytes, Alice's X25519 static key, little endian
Notes
`````
- Bob must perform the usual Router Info validation.
Ensure the signature type is supported, verify the signature,
verify the timestamp is within bounds, and any other checks necessary.
- Bob must verify that Alice's static key received in the first frame matches
the static key in the Router Info. Bob must first search the Router Info for
a NTCP or NTCP2 Router Address with a matching version (v) option.
See Published Router Info and Unpublished Router Info sections below.
- If Bob has an older version of Alice's RouterInfo in his netdb, verify
that the static key in the router info is the same in both, if present,
and if the older version is less than XXX old (see key rotate time below)
- Bob must validate that Alice's static key is a valid point on the curve here.
- Options should be included, to specify padding parameters.
- On any error, including AEAD, RI, DH, timestamp, or key validation failure,
Bob must halt further message processing and close the connection without
responding. This should be an abnormal close (TCP RST).
- To facilitate rapid handshaking, implementations must ensure that Alice
buffers and then flushes the entire contents of the third message at once,
including both AEAD frames.
This increases the likelihood that the data will be contained in a single TCP
packet (unless segmented by the OS or middleboxes), and received all at once
by Bob. This is also for efficiency and to ensure the effectiveness of the
random padding.
- Message 3 part 2 frame length: The length of this frame (including MAC) is
sent by Alice in message 1. See that message for important notes on allowing
enough room for padding.
- Message 3 part 2 frame content: This format of this frame is the same as the
format of data phase frames, except that the length of the frame is sent
by Alice in message 1. See below for the data phase frame format.
The frame must contain 1 to 3 blocks in the following order:
1) Alice's Router Info block (required)
2) Options block (optional)
3) Padding block (optional)
This frame must never contain any other block type.
- Message 3 part 2 padding is not required if Alice appends a data phase frame
(optionally containing padding) to the end of message 3 and sends both at once,
as it will appear as one big stream of bytes to an observer.
As Alice will generally, but not always, have an I2NP message to send to Bob
(that's why she connected to him), this is the recommended implementation,
for efficiency and to ensure the effectiveness of the random padding.
- Total length of both Message 3 AEAD frames (parts 1 and 2) is 65535 bytes;
part 1 is 48 bytes so part 2 max frame length is 65487;
part 2 max plaintext length excluding MAC is 65471.
Key Derivation Function (KDF) (for data phase)
----------------------------------------------
The data phase uses a zero-length associated data input.
The KDF generates two cipher keys k_ab and k_ba from the chaining key ck,
using HMAC-SHA256(key, data) as defined in [RFC-2104].
This is the Split() function, exactly as defined in the Noise spec.
ck = from handshake phase
// k_ab, k_ba = HKDF(ck, zerolen)
// ask_master = HKDF(ck, zerolen, info="ask")
// zerolen is a zero-length byte array
temp_key = HMAC-SHA256(ck, zerolen)
// overwrite the chaining key in memory, no longer needed
ck = (all zeros)
// Output 1
// cipher key, for Alice transmits to Bob (Noise doesn't make clear which is which, but Java code does)
k_ab = HMAC-SHA256(temp_key, byte(0x01)).
// Output 2
// cipher key, for Bob transmits to Alice (Noise doesn't make clear which is which, but Java code does)
k_ba = HMAC-SHA256(temp_key, k_ab || byte(0x02)).
KDF for SipHash for length field:
Generate an Additional Symmetric Key (ask) for SipHash
SipHash uses two 8-byte keys (big endian) and 8 byte IV for first data.
// "ask" is 3 bytes, US-ASCII, no null termination
ask_master = HMAC-SHA256(temp_key, "ask" || byte(0x01))
// sip_master = HKDF(ask_master, h || "siphash")
// "siphash" is 7 bytes, US-ASCII, no null termination
// overwrite previous temp_key in memory
// h is from KDF for message 3 part 2
temp_key = HMAC-SHA256(ask_master, h || "siphash")
// overwrite ask_master in memory, no longer needed
ask_master = (all zeros)
sip_master = HMAC-SHA256(temp_key, byte(0x01))
Alice to Bob SipHash k1, k2, IV:
// sipkeys_ab, sipkeys_ba = HKDF(sip_master, zerolen)
// overwrite previous temp_key in memory
temp_key = HMAC-SHA256(sip_master, zerolen)
// overwrite sip_master in memory, no longer needed
sip_master = (all zeros)
sipkeys_ab = HMAC-SHA256(temp_key, byte(0x01)).
sipk1_ab = sipkeys_ab[0:7], little endian
sipk2_ab = sipkeys_ab[8:15], little endian
sipiv_ab = sipkeys_ab[16:23]
Bob to Alice SipHash k1, k2, IV:
sipkeys_ba = HMAC-SHA256(temp_key, sipkeys_ab || byte(0x02)).
sipk1_ba = sipkeys_ba[0:7], little endian
sipk2_ba = sipkeys_ba[8:15], little endian
sipiv_ba = sipkeys_ba[16:23]
// overwrite the temp_key in memory, no longer needed
temp_key = (all zeros)
**/

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lib/transport/ntcp/sessioncreated.go Normal file
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package ntcp
/**
2) SessionCreated
------------------
Bob sends to Alice.
Noise content: Bob's ephemeral key Y
Noise payload: 16 byte option block
Non-noise payload: Random padding
(Payload Security Properties)
XK(s, rs): Authentication Confidentiality
<- e, ee 2 1
Authentication: 2.
Sender authentication resistant to key-compromise impersonation (KCI).
The sender authentication is based on an ephemeral-static DH ("es" or "se")
between the sender's static key pair and the recipient's ephemeral key pair.
Assuming the corresponding private keys are secure, this authentication cannot be forged.
Confidentiality: 1.
Encryption to an ephemeral recipient.
This payload has forward secrecy, since encryption involves an ephemeral-ephemeral DH ("ee").
However, the sender has not authenticated the recipient,
so this payload might be sent to any party, including an active attacker.
"e": Bob generates a new ephemeral key pair and stores it in the e variable,
writes the ephemeral public key as cleartext into the message buffer,
and hashes the public key along with the old h to derive a new h.
"ee": A DH is performed between the Bob's ephemeral key pair and the Alice's ephemeral key pair.
The result is hashed along with the old ck to derive a new ck and k, and n is set to zero.
The Y value is encrypted to ensure payload indistinguishably and uniqueness,
which are necessary DPI countermeasures. We use AES encryption to achieve
this, rather than more complex and slower alternatives such as elligator2.
Asymmetric encryption to Alice's router public key would be far too slow. AES
encryption uses Bob's router hash as the key and the AES state from message 1
(which was initialized with Bob's IV as published in the network database).
AES encryption is for DPI resistance only. Any party knowing Bob's router hash
and IV, which are published in the network database, and captured the first 32
bytes of message 1, may decrypt the Y value in this message.
Raw contents:
+----+----+----+----+----+----+----+----+
| |
+ obfuscated with RH_B +
| AES-CBC-256 encrypted Y |
+ (32 bytes) +
| |
+ +
| |
+----+----+----+----+----+----+----+----+
| ChaChaPoly frame |
+ Encrypted and authenticated data +
| 32 bytes |
+ k defined in KDF for message 2 +
| n = 0; see KDF for associated data |
+ +
| |
+----+----+----+----+----+----+----+----+
| unencrypted authenticated |
+ padding (optional) +
| length defined in options block |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
Y :: 32 bytes, AES-256-CBC encrypted X25519 ephemeral key, little endian
key: RH_B
iv: Using AES state from message 1
Unencrypted data (Poly1305 auth tag not shown):
+----+----+----+----+----+----+----+----+
| |
+ +
| Y |
+ (32 bytes) +
| |
+ +
| |
+----+----+----+----+----+----+----+----+
| options |
+ (16 bytes) +
| |
+----+----+----+----+----+----+----+----+
| unencrypted authenticated |
+ padding (optional) +
| length defined in options block |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
Y :: 32 bytes, X25519 ephemeral key, little endian
options :: options block, 16 bytes, see below
padding :: Random data, 0 or more bytes.
Total message length must be 65535 bytes or less.
Alice and Bob will use the padding data in the KDF for message 3 part 1.
It is authenticated so that any tampering will cause the
next message to fail.
Notes
`````
- Alice must validate that Bob's ephemeral key is a valid point on the curve
here.
- Padding should be limited to a reasonable amount.
Alice may reject connections with excessive padding.
Alice will specify her padding options in message 3.
Min/max guidelines TBD. Random size from 0 to 31 bytes minimum?
(Distribution is implementation-dependent)
- On any error, including AEAD, DH, timestamp, apparent replay, or key
validation failure, Alice must halt further message processing and close the
connection without responding. This should be an abnormal close (TCP RST).
- To facilitate rapid handshaking, implementations must ensure that Bob buffers
and then flushes the entire contents of the first message at once, including
the padding. This increases the likelihood that the data will be contained
in a single TCP packet (unless segmented by the OS or middleboxes), and
received all at once by Alice. This is also for efficiency and to ensure the
effectiveness of the random padding.
- Alice must fail the connection if any incoming data remains after validating
message 2 and reading in the padding. There should be no extra data from Bob,
as Alice has not responded with message 3 yet.
Options block:
Note: All fields are big-endian.
+----+----+----+----+----+----+----+----+
| Rsvd(0) | padLen | Reserved (0) |
+----+----+----+----+----+----+----+----+
| tsB | Reserved (0) |
+----+----+----+----+----+----+----+----+
Reserved :: 10 bytes total, set to 0 for compatibility with future options
padLen :: 2 bytes, big endian, length of the padding, 0 or more
Min/max guidelines TBD. Random size from 0 to 31 bytes minimum?
(Distribution is implementation-dependent)
tsB :: 4 bytes, big endian, Unix timestamp, unsigned seconds.
Wraps around in 2106
Notes
`````
- Alice must reject connections where the timestamp value is too far off from
the current time. Call the maximum delta time "D". Alice must maintain a
local cache of previously-used handshake values and reject duplicates, to
prevent replay attacks. Values in the cache must have a lifetime of at least
2*D. The cache values are implementation-dependent, however the 32-byte Y
value (or its encrypted equivalent) may be used.
Issues
``````
- Include min/max padding options here?
Encryption for for handshake message 3 part 1, using message 2 KDF)
-------------------------------------------------------------------
// take h saved from message 2 KDF
// MixHash(ciphertext)
h = SHA256(h || 24 byte encrypted payload from message 2)
// MixHash(padding)
// Only if padding length is nonzero
h = SHA256(h || random padding from message 2)
// h is used as the associated data for the AEAD in message 3 part 1, below
This is the "s" message pattern:
Define s = Alice's static public key, 32 bytes
// EncryptAndHash(s.publickey)
// EncryptWithAd(h, s.publickey)
// AEAD_ChaCha20_Poly1305(key, nonce, associatedData, data)
// k is from handshake message 1
// n is 1
ciphertext = AEAD_ChaCha20_Poly1305(k, n++, h, s.publickey)
// MixHash(ciphertext)
// || below means append
h = SHA256(h || ciphertext);
// h is used as the associated data for the AEAD in message 3 part 2
End of "s" message pattern.
Key Derivation Function (KDF) (for handshake message 3 part 2)
--------------------------------------------------------------
This is the "se" message pattern:
// DH(s, re) == DH(e, rs)
Define input_key_material = 32 byte DH result of Alice's static key and Bob's ephemeral key
Set input_key_material = X25519 DH result
// overwrite Bob's ephemeral key in memory, no longer needed
// Alice:
re = (all zeros)
// Bob:
e(public and private) = (all zeros)
// MixKey(DH())
Define temp_key = 32 bytes
Define HMAC-SHA256(key, data) as in [RFC-2104]
// Generate a temp key from the chaining key and DH result
// ck is the chaining key, from the KDF for handshake message 1
temp_key = HMAC-SHA256(ck, input_key_material)
// overwrite the DH result in memory, no longer needed
input_key_material = (all zeros)
// Output 1
// Set a new chaining key from the temp key
// byte() below means a single byte
ck = HMAC-SHA256(temp_key, byte(0x01)).
// Output 2
// Generate the cipher key k
Define k = 32 bytes
// || below means append
// byte() below means a single byte
k = HMAC-SHA256(temp_key, ck || byte(0x02)).
// h from message 3 part 1 is used as the associated data for the AEAD in message 3 part 2
// EncryptAndHash(payload)
// EncryptWithAd(h, payload)
// AEAD_ChaCha20_Poly1305(key, nonce, associatedData, data)
// n is 0
ciphertext = AEAD_ChaCha20_Poly1305(k, n++, h, payload)
// MixHash(ciphertext)
// || below means append
h = SHA256(h || ciphertext);
// retain the chaining key ck for the data phase KDF
// retain the hash h for the data phase Additional Symmetric Key (SipHash) KDF
End of "se" message pattern.
// overwrite the temp_key in memory, no longer needed
temp_key = (all zeros)
**/

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lib/transport/ntcp/sessionrequest.go Normal file
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package ntcp
/**
1) SessionRequest
------------------
Alice sends to Bob.
Noise content: Alice's ephemeral key X
Noise payload: 16 byte option block
Non-noise payload: Random padding
(Payload Security Properties)
XK(s, rs): Authentication Confidentiality
-> e, es 0 2
Authentication: None (0).
This payload may have been sent by any party, including an active attacker.
Confidentiality: 2.
Encryption to a known recipient, forward secrecy for sender compromise
only, vulnerable to replay. This payload is encrypted based only on DHs
involving the recipient's static key pair. If the recipient's static
private key is compromised, even at a later date, this payload can be
decrypted. This message can also be replayed, since there's no ephemeral
contribution from the recipient.
"e": Alice generates a new ephemeral key pair and stores it in the e
variable, writes the ephemeral public key as cleartext into the
message buffer, and hashes the public key along with the old h to
derive a new h.
"es": A DH is performed between the Alice's ephemeral key pair and the
Bob's static key pair. The result is hashed along with the old ck to
derive a new ck and k, and n is set to zero.
The X value is encrypted to ensure payload indistinguishably
and uniqueness, which are necessary DPI countermeasures.
We use AES encryption to achieve this,
rather than more complex and slower alternatives such as elligator2.
Asymmetric encryption to Bob's router public key would be far too slow.
AES encryption uses Bob's router hash as the key and Bob's IV as published
in the network database.
AES encryption is for DPI resistance only.
Any party knowing Bob's router hash, and IV, which are published in the network database,
may decrypt the X value in this message.
The padding is not encrypted by Alice.
It may be necessary for Bob to decrypt the padding,
to inhibit timing attacks.
Raw contents:
+----+----+----+----+----+----+----+----+
| |
+ obfuscated with RH_B +
| AES-CBC-256 encrypted X |
+ (32 bytes) +
| |
+ +
| |
+----+----+----+----+----+----+----+----+
| |
+ +
| ChaChaPoly frame |
+ (32 bytes) +
| k defined in KDF for message 1 |
+ n = 0 +
| see KDF for associated data |
+----+----+----+----+----+----+----+----+
| unencrypted authenticated |
~ padding (optional) ~
| length defined in options block |
+----+----+----+----+----+----+----+----+
X :: 32 bytes, AES-256-CBC encrypted X25519 ephemeral key, little endian
key: RH_B
iv: As published in Bobs network database entry
padding :: Random data, 0 or more bytes.
Total message length must be 65535 bytes or less.
Total message length must be 287 bytes or less if
Bob is publishing his address as NTCP
(see Version Detection section below).
Alice and Bob will use the padding data in the KDF for message 2.
It is authenticated so that any tampering will cause the
next message to fail.
Unencrypted data (Poly1305 authentication tag not shown):
+----+----+----+----+----+----+----+----+
| |
+ +
| X |
+ (32 bytes) +
| |
+ +
| |
+----+----+----+----+----+----+----+----+
| options |
+ (16 bytes) +
| |
+----+----+----+----+----+----+----+----+
| unencrypted authenticated |
+ padding (optional) +
| length defined in options block |
~ . . . ~
| |
+----+----+----+----+----+----+----+----+
X :: 32 bytes, X25519 ephemeral key, little endian
options :: options block, 16 bytes, see below
padding :: Random data, 0 or more bytes.
Total message length must be 65535 bytes or less.
Total message length must be 287 bytes or less if
Bob is publishing his address as "NTCP"
(see Version Detection section below)
Alice and Bob will use the padding data in the KDF for message 2.
It is authenticated so that any tampering will cause the
next message to fail.
Options block:
Note: All fields are big-endian.
+----+----+----+----+----+----+----+----+
| id | ver| padLen | m3p2len | Rsvd(0) |
+----+----+----+----+----+----+----+----+
| tsA | Reserved (0) |
+----+----+----+----+----+----+----+----+
id :: 1 byte, the network ID (currently 2, except for test networks)
As of 0.9.42. See proposal 147.
ver :: 1 byte, protocol version (currently 2)
padLen :: 2 bytes, length of the padding, 0 or more
Min/max guidelines TBD. Random size from 0 to 31 bytes minimum?
(Distribution is implementation-dependent)
m3p2Len :: 2 bytes, length of the the second AEAD frame in SessionConfirmed
(message 3 part 2) See notes below
Rsvd :: 2 bytes, set to 0 for compatibility with future options
tsA :: 4 bytes, Unix timestamp, unsigned seconds.
Wraps around in 2106
Reserved :: 4 bytes, set to 0 for compatibility with future options
Notes
`````
- When the published address is "NTCP", Bob supports both NTCP and NTCP2 on the
same port. For compatibility, when initiating a connection to an address
published as "NTCP", Alice must limit the maximum size of this message,
including padding, to 287 bytes or less. This facilitates automatic protocol
identification by Bob. When published as "NTCP2", there is no size
restriction. See the Published Addresses and Version Detection sections
below.
- The unique X value in the initial AES block ensure that the ciphertext is
different for every session.
- Bob must reject connections where the timestamp value is too far off from the
current time. Call the maximum delta time "D". Bob must maintain a local
cache of previously-used handshake values and reject duplicates, to prevent
replay attacks. Values in the cache must have a lifetime of at least 2*D.
The cache values are implementation-dependent, however the 32-byte X value
(or its encrypted equivalent) may be used.
- Diffie-Hellman ephemeral keys may never be reused, to prevent cryptographic attacks,
and reuse will be rejected as a replay attack.
- The "KE" and "auth" options must be compatible, i.e. the shared secret K must
be of the appropriate size. If more "auth" options are added, this could
implicitly change the meaning of the "KE" flag to use a different KDF or a
different truncation size.
- Bob must validate that Alice's ephemeral key is a valid point on the curve
here.
- Padding should be limited to a reasonable amount. Bob may reject connections
with excessive padding. Bob will specify his padding options in message 2.
Min/max guidelines TBD. Random size from 0 to 31 bytes minimum?
(Distribution is implementation-dependent)
- On any error, including AEAD, DH, timestamp, apparent replay, or key
validation failure, Bob must halt further message processing and close the
connection without responding. This should be an abnormal close (TCP RST).
For probing resistance, after an AEAD failure, Bob should
set a random timeout (range TBD) and then read a random number of bytes (range TBD),
before closing the socket.
- DoS Mitigation: DH is a relatively expensive operation. As with the previous NTCP protocol,
routers should take all necessary measures to prevent CPU or connection exhaustion.
Place limits on maximum active connections and maximum connection setups in progress.
Enforce read timeouts (both per-read and total for "slowloris").
Limit repeated or simultaneous connections from the same source.
Maintain blacklists for sources that repeatedly fail.
Do not respond to AEAD failure.
- To facilitate rapid version detection and handshaking, implementations must
ensure that Alice buffers and then flushes the entire contents of the first
message at once, including the padding. This increases the likelihood that
the data will be contained in a single TCP packet (unless segmented by the OS
or middleboxes), and received all at once by Bob. Additionally,
implementations must ensure that Bob buffers and then flushes the entire
contents of the second message at once, including the padding. and that Bob
buffers and then flushes the entire contents of the third message at once.
This is also for efficiency and to ensure the effectiveness of the random
padding.
- "ver" field: The overall Noise protocol, extensions, and NTCP protocol
including payload specifications, indicating NTCP2.
This field may be used to indicate support for future changes.
- Message 3 part 2 length: This is the size of the second AEAD frame (including 16-byte MAC)
containing Alice's Router Info and optional padding that will be sent in
the SessionConfirmed message. As routers periodically regenerate and republish
their Router Info, the size of the current Router Info may change before
message 3 is sent. Implementations must choose one of two strategies:
a) save the current Router Info to be sent in message 3, so the size is known,
and optionally add room for padding;
b) increase the specified size enough to allow for possible increase in
the Router Info size, and always add padding when message 3 is actually sent.
In either case, the "m3p2len" length included in message 1 must be exactly the
size of that frame when sent in message 3.
- Bob must fail the connection if any incoming data remains after validating
message 1 and reading in the padding. There should be no extra data from Alice,
as Bob has not responded with message 2 yet.
- The network ID field is used to quickly identify cross-network connections.
If this field is nonzero, and does not match Bob's network ID,
Bob should disconnect and block future connections.
Any connections from test networks should have a different ID and will fail the test.
As of 0.9.42. See proposal 147 for more information.
Key Derivation Function (KDF) (for handshake message 2 and message 3 part 1)
----------------------------------------------------------------------------
// take h saved from message 1 KDF
// MixHash(ciphertext)
h = SHA256(h || 32 byte encrypted payload from message 1)
// MixHash(padding)
// Only if padding length is nonzero
h = SHA256(h || random padding from message 1)
This is the "e" message pattern:
Bob generates his ephemeral DH key pair e.
// h is from KDF for handshake message 1
// Bob ephemeral key Y
// MixHash(e.pubkey)
// || below means append
h = SHA256(h || e.pubkey);
// h is used as the associated data for the AEAD in message 2
// Retain the Hash h for the message 3 KDF
End of "e" message pattern.
This is the "ee" message pattern:
// DH(e, re)
Define input_key_material = 32 byte DH result of Alice's ephemeral key and Bob's ephemeral key
Set input_key_material = X25519 DH result
// overwrite Alice's ephemeral key in memory, no longer needed
// Alice:
e(public and private) = (all zeros)
// Bob:
re = (all zeros)
// MixKey(DH())
Define temp_key = 32 bytes
Define HMAC-SHA256(key, data) as in [RFC-2104]
// Generate a temp key from the chaining key and DH result
// ck is the chaining key, from the KDF for handshake message 1
temp_key = HMAC-SHA256(ck, input_key_material)
// overwrite the DH result in memory, no longer needed
input_key_material = (all zeros)
// Output 1
// Set a new chaining key from the temp key
// byte() below means a single byte
ck = HMAC-SHA256(temp_key, byte(0x01)).
// Output 2
// Generate the cipher key k
Define k = 32 bytes
// || below means append
// byte() below means a single byte
k = HMAC-SHA256(temp_key, ck || byte(0x02)).
// overwrite the temp_key in memory, no longer needed
temp_key = (all zeros)
// retain the chaining key ck for message 3 KDF
End of "ee" message pattern.
**/

10
lib/transport/ntcp/transport.go
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@@ -1,5 +1,15 @@
package ntcp
/**
* https://geti2p.net/spec/ntcp2
**/
const (
NTCP_PROTOCOL_VERSION = 2
NTCP_PROTOCOL_NAME = "NTCP2"
NTCP_MESSAGE_MAX_SIZE = 65537
)
// Transport is an ntcp transport implementing transport.Transport interface
type Transport struct {
}