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|
package auth
import (
"context"
"fmt"
"strings"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/status"
)
type contextKey string
const (
pubkeyContextKey contextKey = "nostr-pubkey"
)
type InterceptorOptions struct {
Read OperationAuthConfig
Write OperationAuthConfig
TimestampWindow int64
ValidatePayload bool
SkipMethods []string
}
// OperationAuthConfig configures auth for read or write operations.
// Three states: disabled (allow all), enabled with empty list (require auth),
// enabled with npubs (whitelist only). Npubs normalized to hex at load time.
type OperationAuthConfig struct {
Enabled bool
AllowedNpubs []string
}
func DefaultInterceptorOptions() *InterceptorOptions {
return &InterceptorOptions{
Read: OperationAuthConfig{
Enabled: false,
AllowedNpubs: nil,
},
Write: OperationAuthConfig{
Enabled: false,
AllowedNpubs: nil,
},
TimestampWindow: 60,
ValidatePayload: false,
SkipMethods: nil,
}
}
func NostrUnaryInterceptor(opts *InterceptorOptions) grpc.UnaryServerInterceptor {
if opts == nil {
opts = DefaultInterceptorOptions()
}
return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
if shouldSkipAuth(info.FullMethod, opts.SkipMethods) {
return handler(ctx, req)
}
var authRequired bool
if isWriteMethod(info.FullMethod) {
authRequired = opts.Write.Enabled
} else {
authRequired = opts.Read.Enabled
}
if !authRequired {
return handler(ctx, req)
}
pubkey, err := validateAuthFromContext(ctx, info.FullMethod, opts)
if err != nil {
return nil, status.Error(codes.Unauthenticated, err.Error())
}
ctx = context.WithValue(ctx, pubkeyContextKey, pubkey)
return handler(ctx, req)
}
}
func NostrStreamInterceptor(opts *InterceptorOptions) grpc.StreamServerInterceptor {
if opts == nil {
opts = DefaultInterceptorOptions()
}
return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
if shouldSkipAuth(info.FullMethod, opts.SkipMethods) {
return handler(srv, ss)
}
var authRequired bool
if isWriteMethod(info.FullMethod) {
authRequired = opts.Write.Enabled
} else {
authRequired = opts.Read.Enabled
}
if !authRequired {
return handler(srv, ss)
}
ctx := ss.Context()
pubkey, err := validateAuthFromContext(ctx, info.FullMethod, opts)
if err != nil {
return status.Error(codes.Unauthenticated, err.Error())
}
wrappedStream := &authenticatedStream{
ServerStream: ss,
ctx: context.WithValue(ctx, pubkeyContextKey, pubkey),
}
return handler(srv, wrappedStream)
}
}
type authenticatedStream struct{
grpc.ServerStream
ctx context.Context
}
func (s *authenticatedStream) Context() context.Context {
return s.ctx
}
func validateAuthFromContext(ctx context.Context, method string, opts *InterceptorOptions) (string, error) {
md, ok := metadata.FromIncomingContext(ctx)
if !ok {
return "", fmt.Errorf("missing metadata")
}
authHeaders := md.Get("authorization")
if len(authHeaders) == 0 {
return "", fmt.Errorf("missing authorization header")
}
event, err := ParseAuthHeader(authHeaders[0])
if err != nil {
return "", fmt.Errorf("invalid auth header: %w", err)
}
validationOpts := ValidationOptions{
TimestampWindow: opts.TimestampWindow,
ValidatePayload: opts.ValidatePayload,
ExpectedMethod: "POST",
}
if err := ValidateAuthEvent(event, validationOpts); err != nil {
return "", fmt.Errorf("invalid auth event: %w", err)
}
pubkey := ExtractPubkey(event)
var opConfig OperationAuthConfig
if isWriteMethod(method) {
opConfig = opts.Write
} else {
opConfig = opts.Read
}
if len(opConfig.AllowedNpubs) > 0 {
if !contains(opConfig.AllowedNpubs, pubkey) {
if isWriteMethod(method) {
return "", fmt.Errorf("pubkey not authorized for write operations")
}
return "", fmt.Errorf("pubkey not authorized for read operations")
}
}
return pubkey, nil
}
func isWriteMethod(method string) bool {
return strings.Contains(method, "/PublishEvent") || strings.Contains(method, "/PublishBatch")
}
func shouldSkipAuth(method string, skipMethods []string) bool {
for _, skip := range skipMethods {
if skip == method {
return true
}
}
return false
}
func contains(slice []string, item string) bool {
for _, s := range slice {
if s == item {
return true
}
}
return false
}
func PubkeyFromContext(ctx context.Context) (string, bool) {
pubkey, ok := ctx.Value(pubkeyContextKey).(string)
return pubkey, ok
}
func RequireAuth(ctx context.Context) (string, error) {
pubkey, ok := PubkeyFromContext(ctx)
if !ok || pubkey == "" {
return "", status.Error(codes.Unauthenticated, "authentication required")
}
return pubkey, nil
}
|
