Fix SFTP file upload failures with JWT filer tokens (#8448)

* Fix SFTP file upload failures with JWT filer tokens (issue #8425)

When JWT authentication is enabled for filer operations via jwt.filer_signing.*
configuration, SFTP server file upload requests were rejected because they lacked
JWT authorization headers.

Changes:
- Added JWT signing key and expiration fields to SftpServer struct
- Modified putFile() to generate and include JWT tokens in upload requests
- Enhanced SFTPServiceOptions with JWT configuration fields
- Updated SFTP command startup to load and pass JWT config to service

This allows SFTP uploads to authenticate with JWT-enabled filers, consistent
with how other SeaweedFS components (S3 API, file browser) handle filer auth.

Fixes #8425

* Apply suggestion from @gemini-code-assist[bot]

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

weed/command/sftp.go

@@ -101,6 +101,12 @@ func (sftpOpt *SftpOptions) startSftpServer() bool {
 	filerAddress := pb.ServerAddress(*sftpOpt.filer)
 	grpcDialOption := security.LoadClientTLS(util.GetViper(), "grpc.client")
 
+	// Load JWT configuration for filer signing
+	v := util.GetViper()
+	filerSigningKey := v.GetString("jwt.filer_signing.key")
+	v.SetDefault("jwt.filer_signing.expires_after_seconds", 600)
+	filerSigningExpiresAfter := v.GetInt("jwt.filer_signing.expires_after_seconds")
+
 	// metrics read from the filer
 	var metricsAddress string
 	var metricsIntervalSec int
@@ -150,6 +156,8 @@ func (sftpOpt *SftpOptions) startSftpServer() bool {
 		ClientAliveInterval:      *sftpOpt.clientAliveInterval,
 		ClientAliveCountMax:      *sftpOpt.clientAliveCountMax,
 		UserStoreFile:            *sftpOpt.userStoreFile,
+		FilerSigningKey:          []byte(filerSigningKey),
+		FilerSigningExpiresAfter: filerSigningExpiresAfter,
 	})
 
 	// Register reload hook for HUP signal

weed/sftpd/sftp_filer.go

@@ -17,6 +17,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/pb"
 	filer_pb "github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
+	"github.com/seaweedfs/seaweedfs/weed/security"
 	weed_server "github.com/seaweedfs/seaweedfs/weed/server"
 	"github.com/seaweedfs/seaweedfs/weed/sftpd/user"
 	"github.com/seaweedfs/seaweedfs/weed/util"
@@ -333,6 +334,14 @@ func (fs *SftpServer) putFile(filepath string, reader io.Reader, user *user.User
 	}
 	req.Header.Set("Content-Type", "application/octet-stream")
 
+	// Add JWT authorization if filer signing key is configured
+	if len(fs.filerSigningKey) > 0 {
+		jwt := security.GenJwtForFilerServer(security.SigningKey(fs.filerSigningKey), fs.filerSigningExpiresAfter)
+		if jwt != "" {
+			req.Header.Set("Authorization", "Bearer "+string(jwt))
+		}
+	}
+
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return fmt.Errorf("upload to filer: %w", err)

weed/sftpd/sftp_server.go

@@ -25,10 +25,12 @@ type SftpServer struct {
 	dataCenter               string
 	filerGroup               string
 	user                     *user.User
+	filerSigningKey          []byte
+	filerSigningExpiresAfter int
 }
 
 // NewSftpServer constructs the server.
-func NewSftpServer(filerAddr pb.ServerAddress, grpcDialOption grpc.DialOption, dataCenter, filerGroup string, user *user.User) SftpServer {
+func NewSftpServer(filerAddr pb.ServerAddress, grpcDialOption grpc.DialOption, dataCenter, filerGroup string, user *user.User, filerSigningKey []byte, filerSigningExpiresAfter int) SftpServer {
 
 	return SftpServer{
 		filerAddr:                filerAddr,
@@ -36,6 +38,8 @@ func NewSftpServer(filerAddr pb.ServerAddress, grpcDialOption grpc.DialOption, d
 		dataCenter:               dataCenter,
 		filerGroup:               filerGroup,
 		user:                     user,
+		filerSigningKey:          filerSigningKey,
+		filerSigningExpiresAfter: filerSigningExpiresAfter,
 	}
 }
 

weed/sftpd/sftp_service.go

@@ -47,6 +47,10 @@ type SFTPServiceOptions struct {
 
 	// User Management
 	UserStoreFile string // Path to user store file
+
+	// JWT Configuration for Filer
+	FilerSigningKey          []byte // JWT signing key for filer uploads
+	FilerSigningExpiresAfter int    // JWT token expiration time in seconds
 }
 
 // NewSFTPService creates a new service instance.
@@ -201,6 +205,8 @@ func (s *SFTPService) handleSSHConnection(conn net.Conn, config *ssh.ServerConfi
 		s.options.DataCenter,
 		s.options.FilerGroup,
 		sftpUser,
+		s.options.FilerSigningKey,
+		s.options.FilerSigningExpiresAfter,
 	)
 
 	// Ensure home directory exists with proper permissions