nip-46 dynamic and static signers.

This commit is contained in:
fiatjaf 2024-01-09 16:55:00 -03:00
parent ce424619f4
commit fd8b2b22b2
No known key found for this signature in database
GPG Key ID: BAD43C4BE5C1A3A1
3 changed files with 325 additions and 72 deletions

218
nip46/dynamic-signer.go Normal file
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@ -0,0 +1,218 @@
package nip46
import (
"encoding/json"
"fmt"
"sync"
"github.com/mailru/easyjson"
"github.com/nbd-wtf/go-nostr"
"github.com/nbd-wtf/go-nostr/nip04"
"golang.org/x/exp/slices"
)
var _ Signer = (*DynamicSigner)(nil)
type DynamicSigner struct {
sessionKeys []string
sessions []Session
sync.Mutex
RelaysToAdvertise map[string]RelayReadWrite
getPrivateKey func(pubkey string) (string, error)
authorizeSigning func(event nostr.Event) bool
onEventSigned func(event nostr.Event)
authorizeNIP04 func() bool
}
func NewDynamicSigner(
getPrivateKey func(pubkey string) (string, error),
authorizeSigning func(event nostr.Event) bool,
onEventSigned func(event nostr.Event),
authorizeNIP04 func() bool,
) DynamicSigner {
return DynamicSigner{
getPrivateKey: getPrivateKey,
authorizeSigning: authorizeSigning,
onEventSigned: onEventSigned,
authorizeNIP04: authorizeNIP04,
RelaysToAdvertise: make(map[string]RelayReadWrite),
}
}
func (p *DynamicSigner) GetSession(clientPubkey string) (Session, bool) {
idx, exists := slices.BinarySearch(p.sessionKeys, clientPubkey)
if exists {
return p.sessions[idx], true
}
return Session{}, false
}
func (p *DynamicSigner) setSession(clientPubkey string, session Session) {
p.Lock()
defer p.Unlock()
idx, exists := slices.BinarySearch(p.sessionKeys, clientPubkey)
if exists {
return
}
// add to pool
p.sessionKeys = append(p.sessionKeys, "") // bogus append just to increase the capacity
p.sessions = append(p.sessions, Session{})
copy(p.sessionKeys[idx+1:], p.sessionKeys[idx:])
copy(p.sessions[idx+1:], p.sessions[idx:])
p.sessionKeys[idx] = clientPubkey
p.sessions[idx] = session
}
func (p *DynamicSigner) HandleRequest(event *nostr.Event) (
req Request,
resp Response,
eventResponse nostr.Event,
harmless bool,
err error,
) {
if event.Kind != nostr.KindNostrConnect {
return req, resp, eventResponse, false,
fmt.Errorf("event kind is %d, but we expected %d", event.Kind, nostr.KindNostrConnect)
}
targetUser := event.Tags.GetFirst([]string{"p", ""})
if targetUser == nil || !nostr.IsValidPublicKeyHex((*targetUser)[1]) {
return req, resp, eventResponse, false, fmt.Errorf("invalid \"p\" tag")
}
targetPubkey := (*targetUser)[1]
privateKey, err := p.getPrivateKey(targetPubkey)
if err != nil {
return req, resp, eventResponse, false, fmt.Errorf("no private key for %s: %w", targetPubkey, err)
}
var session Session
idx, exists := slices.BinarySearch(p.sessionKeys, event.PubKey)
if exists {
session = p.sessions[idx]
} else {
session = Session{}
session.SharedKey, err = nip04.ComputeSharedSecret(event.PubKey, privateKey)
if err != nil {
return req, resp, eventResponse, false, fmt.Errorf("failed to compute shared secret: %w", err)
}
p.setSession(event.PubKey, session)
req, err = session.ParseRequest(event)
if err != nil {
return req, resp, eventResponse, false, fmt.Errorf("error parsing request: %w", err)
}
}
var result string
var resultErr error
switch req.Method {
case "connect":
result = "ack"
harmless = true
case "get_public_key":
result = targetPubkey
harmless = true
case "sign_event":
if len(req.Params) != 1 {
resultErr = fmt.Errorf("wrong number of arguments to 'sign_event'")
break
}
evt := nostr.Event{}
err = easyjson.Unmarshal([]byte(req.Params[0]), &evt)
if err != nil {
resultErr = fmt.Errorf("failed to decode event/2: %w", err)
break
}
if !p.authorizeSigning(evt) {
resultErr = fmt.Errorf("refusing to sign this event")
break
}
err = evt.Sign(privateKey)
if err != nil {
resultErr = fmt.Errorf("failed to sign event: %w", err)
break
}
jrevt, _ := easyjson.Marshal(evt)
result = string(jrevt)
case "get_relays":
jrelays, _ := json.Marshal(p.RelaysToAdvertise)
result = string(jrelays)
harmless = true
case "nip04_encrypt":
if len(req.Params) != 2 {
resultErr = fmt.Errorf("wrong number of arguments to 'nip04_encrypt'")
break
}
thirdPartyPubkey := req.Params[0]
if !nostr.IsValidPublicKeyHex(thirdPartyPubkey) {
resultErr = fmt.Errorf("first argument to 'nip04_encrypt' is not a pubkey string")
break
}
if !p.authorizeNIP04() {
resultErr = fmt.Errorf("refusing to encrypt")
break
}
plaintext := req.Params[1]
sharedSecret, err := nip04.ComputeSharedSecret(thirdPartyPubkey, privateKey)
if err != nil {
resultErr = fmt.Errorf("failed to compute shared secret: %w", err)
break
}
ciphertext, err := nip04.Encrypt(plaintext, sharedSecret)
if err != nil {
resultErr = fmt.Errorf("failed to encrypt: %w", err)
break
}
result = ciphertext
case "nip04_decrypt":
if len(req.Params) != 2 {
resultErr = fmt.Errorf("wrong number of arguments to 'nip04_decrypt'")
break
}
thirdPartyPubkey := req.Params[0]
if !nostr.IsValidPublicKeyHex(thirdPartyPubkey) {
resultErr = fmt.Errorf("first argument to 'nip04_decrypt' is not a pubkey string")
break
}
if !p.authorizeNIP04() {
resultErr = fmt.Errorf("refusing to decrypt")
break
}
ciphertext := req.Params[1]
sharedSecret, err := nip04.ComputeSharedSecret(thirdPartyPubkey, privateKey)
if err != nil {
resultErr = fmt.Errorf("failed to compute shared secret: %w", err)
break
}
plaintext, err := nip04.Decrypt(ciphertext, sharedSecret)
if err != nil {
resultErr = fmt.Errorf("failed to encrypt: %w", err)
break
}
result = plaintext
default:
return req, resp, eventResponse, false,
fmt.Errorf("unknown method '%s'", req.Method)
}
resp, eventResponse, err = session.MakeResponse(req.ID, event.PubKey, result, resultErr)
if err != nil {
return req, resp, eventResponse, harmless, err
}
err = eventResponse.Sign(privateKey)
if err != nil {
return req, resp, eventResponse, harmless, err
}
return req, resp, eventResponse, harmless, err
}

79
nip46/nip46.go Normal file
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@ -0,0 +1,79 @@
package nip46
import (
"encoding/json"
"fmt"
"github.com/nbd-wtf/go-nostr"
"github.com/nbd-wtf/go-nostr/nip04"
)
type Request struct {
ID string `json:"id"`
Method string `json:"method"`
Params []string `json:"params"`
}
type Response struct {
ID string `json:"id"`
Error string `json:"error,omitempty"`
Result string `json:"result,omitempty"`
}
type Signer interface {
GetSession(clientPubkey string) (Session, bool)
HandleRequest(event *nostr.Event) (req Request, resp Response, eventResponse nostr.Event, harmless bool, err error)
}
type Session struct {
SharedKey []byte
}
type RelayReadWrite struct {
Read bool `json:"read"`
Write bool `json:"write"`
}
func (s Session) ParseRequest(event *nostr.Event) (Request, error) {
var req Request
plain, err := nip04.Decrypt(event.Content, s.SharedKey)
if err != nil {
return req, fmt.Errorf("failed to decrypt event from %s: %w", event.PubKey, err)
}
err = json.Unmarshal([]byte(plain), &req)
return req, err
}
func (s Session) MakeResponse(
id string,
requester string,
result string,
err error,
) (resp Response, evt nostr.Event, error error) {
if err != nil {
resp = Response{
ID: id,
Error: err.Error(),
}
} else if result != "" {
resp = Response{
ID: id,
Result: result,
}
}
jresp, _ := json.Marshal(resp)
ciphertext, err := nip04.Encrypt(string(jresp), s.SharedKey)
if err != nil {
return resp, evt, fmt.Errorf("failed to encrypt result: %w", err)
}
evt.Content = ciphertext
evt.CreatedAt = nostr.Now()
evt.Kind = nostr.KindNostrConnect
evt.Tags = nostr.Tags{nostr.Tag{"p", requester}}
return resp, evt, nil
}

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@ -3,6 +3,7 @@ package nip46
import (
"encoding/json"
"fmt"
"sync"
"github.com/mailru/easyjson"
"github.com/nbd-wtf/go-nostr"
@ -10,89 +11,38 @@ import (
"golang.org/x/exp/slices"
)
type Request struct {
ID string `json:"id"`
Method string `json:"method"`
Params []string `json:"params"`
}
var _ Signer = (*StaticKeySigner)(nil)
type Response struct {
ID string `json:"id"`
Error string `json:"error,omitempty"`
Result string `json:"result,omitempty"`
}
type Session struct {
SharedKey []byte
}
func (s Session) ParseRequest(event *nostr.Event) (Request, error) {
var req Request
plain, err := nip04.Decrypt(event.Content, s.SharedKey)
if err != nil {
return req, fmt.Errorf("failed to decrypt event from %s: %w", event.PubKey, err)
}
err = json.Unmarshal([]byte(plain), &req)
return req, err
}
func (s Session) MakeResponse(
id string,
requester string,
result string,
err error,
) (resp Response, evt nostr.Event, error error) {
if err != nil {
resp = Response{
ID: id,
Error: err.Error(),
}
} else if result != "" {
resp = Response{
ID: id,
Result: result,
}
}
jresp, _ := json.Marshal(resp)
ciphertext, err := nip04.Encrypt(string(jresp), s.SharedKey)
if err != nil {
return resp, evt, fmt.Errorf("failed to encrypt result: %w", err)
}
evt.Content = ciphertext
evt.CreatedAt = nostr.Now()
evt.Kind = nostr.KindNostrConnect
evt.Tags = nostr.Tags{nostr.Tag{"p", requester}}
return resp, evt, nil
}
type Signer struct {
type StaticKeySigner struct {
secretKey string
sessionKeys []string
sessions []Session
RelaysToAdvertise map[string]relayReadWrite
sync.Mutex
RelaysToAdvertise map[string]RelayReadWrite
}
type relayReadWrite struct {
Read bool `json:"read"`
Write bool `json:"write"`
func NewStaticKeySigner(secretKey string) StaticKeySigner {
return StaticKeySigner{
secretKey: secretKey,
RelaysToAdvertise: make(map[string]RelayReadWrite),
}
}
func NewSigner(secretKey string) Signer {
return Signer{secretKey: secretKey}
func (p *StaticKeySigner) GetSession(clientPubkey string) (Session, bool) {
idx, exists := slices.BinarySearch(p.sessionKeys, clientPubkey)
if exists {
return p.sessions[idx], true
}
return Session{}, false
}
func (p *Signer) AddRelayToAdvertise(url string, read bool, write bool) {
p.RelaysToAdvertise[url] = relayReadWrite{read, write}
}
func (p *StaticKeySigner) getOrCreateSession(clientPubkey string) (Session, error) {
p.Lock()
defer p.Unlock()
func (p *Signer) GetSession(clientPubkey string) (Session, error) {
idx, exists := slices.BinarySearch(p.sessionKeys, clientPubkey)
if exists {
return p.sessions[idx], nil
@ -118,13 +68,19 @@ func (p *Signer) GetSession(clientPubkey string) (Session, error) {
return session, nil
}
func (p *Signer) HandleRequest(event *nostr.Event) (req Request, resp Response, eventResponse nostr.Event, harmless bool, err error) {
func (p *StaticKeySigner) HandleRequest(event *nostr.Event) (
req Request,
resp Response,
eventResponse nostr.Event,
harmless bool,
err error,
) {
if event.Kind != nostr.KindNostrConnect {
return req, resp, eventResponse, false,
fmt.Errorf("event kind is %d, but we expected %d", event.Kind, nostr.KindNostrConnect)
}
session, err := p.GetSession(event.PubKey)
session, err := p.getOrCreateSession(event.PubKey)
if err != nil {
return req, resp, eventResponse, false, err
}