fix(auth): reject invalid bearer tokens instead of falling back

Modify the authentication handler to return an unauthorized error when
an invalid or disabled bearer token is provided, rather than silently
falling back to an anonymous request.

This ensures that clients attempting to authenticate but failing (due to
expired, malformed, or disabled tokens) are explicitly notified of the
auth failure instead of proceeding anonymously. True anonymous requests
without any Authorization header remain supported.

backend/libs/services/storage_sftp.go

@@ -0,0 +1,200 @@
+package services
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/pkg/sftp"
+	"golang.org/x/crypto/ssh"
+)
+
+type sftpStorageBackend struct {
+	cfg StorageBackendConfig
+}
+
+func (b sftpStorageBackend) ID() string   { return b.cfg.ID }
+func (b sftpStorageBackend) Type() string { return StorageBackendSFTP }
+
+func (b sftpStorageBackend) Put(ctx context.Context, key string, body io.Reader, _ int64, _ string) error {
+	client, closer, err := b.client()
+	if err != nil {
+		return err
+	}
+	defer closer()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	remotePath := b.remotePath(key)
+	if err := client.MkdirAll(path.Dir(remotePath)); err != nil {
+		return err
+	}
+	target, err := client.OpenFile(remotePath, os.O_CREATE|os.O_TRUNC|os.O_WRONLY)
+	if err != nil {
+		return err
+	}
+	defer target.Close()
+	_, err = io.Copy(target, body)
+	return err
+}
+
+func (b sftpStorageBackend) Get(ctx context.Context, key string) (StorageObject, error) {
+	client, closer, err := b.client()
+	if err != nil {
+		return StorageObject{}, err
+	}
+	if err := ctx.Err(); err != nil {
+		closer()
+		return StorageObject{}, err
+	}
+	remotePath := b.remotePath(key)
+	source, err := client.Open(remotePath)
+	if err != nil {
+		closer()
+		return StorageObject{}, err
+	}
+	stat, err := source.Stat()
+	if err != nil {
+		source.Close()
+		closer()
+		return StorageObject{}, err
+	}
+	return StorageObject{Key: key, Size: stat.Size(), ModTime: stat.ModTime(), Body: closeWith(source, closer)}, nil
+}
+
+func (b sftpStorageBackend) Delete(ctx context.Context, key string) error {
+	client, closer, err := b.client()
+	if err != nil {
+		return err
+	}
+	defer closer()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	if err := client.Remove(b.remotePath(key)); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
+func (b sftpStorageBackend) DeletePrefix(ctx context.Context, prefix string) error {
+	client, closer, err := b.client()
+	if err != nil {
+		return err
+	}
+	defer closer()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	remotePath := b.remotePath(prefix)
+	if err := client.RemoveDirectory(remotePath); err == nil || os.IsNotExist(err) {
+		return nil
+	}
+	walker := client.Walk(remotePath)
+	paths := make([]string, 0)
+	for walker.Step() {
+		if walker.Err() != nil {
+			return walker.Err()
+		}
+		paths = append(paths, walker.Path())
+	}
+	sort.Slice(paths, func(i, j int) bool { return len(paths[i]) > len(paths[j]) })
+	for _, item := range paths {
+		if err := client.Remove(item); err != nil {
+			_ = client.RemoveDirectory(item)
+		}
+	}
+	_ = client.RemoveDirectory(remotePath)
+	return nil
+}
+
+func (b sftpStorageBackend) Usage(ctx context.Context) (int64, error) {
+	client, closer, err := b.client()
+	if err != nil {
+		return 0, err
+	}
+	defer closer()
+	if err := ctx.Err(); err != nil {
+		return 0, err
+	}
+	var total int64
+	walker := client.Walk(cleanRemoteRoot(b.cfg.RemotePath))
+	for walker.Step() {
+		if walker.Err() != nil {
+			return 0, walker.Err()
+		}
+		info := walker.Stat()
+		if info != nil && !info.IsDir() {
+			total += info.Size()
+		}
+	}
+	return total, nil
+}
+
+func (b sftpStorageBackend) Test(ctx context.Context) error {
+	key := ".warpbox-storage-test-" + randomID(6)
+	if err := b.Put(ctx, key, strings.NewReader("ok"), 2, "text/plain"); err != nil {
+		return err
+	}
+	return b.Delete(ctx, key)
+}
+
+func (b sftpStorageBackend) client() (*sftp.Client, func(), error) {
+	auth := make([]ssh.AuthMethod, 0, 2)
+	if b.cfg.PrivateKey != "" {
+		signer, err := ssh.ParsePrivateKey([]byte(b.cfg.PrivateKey))
+		if err != nil {
+			return nil, nil, err
+		}
+		auth = append(auth, ssh.PublicKeys(signer))
+	}
+	if b.cfg.Password != "" {
+		auth = append(auth, ssh.Password(b.cfg.Password))
+	}
+	if len(auth) == 0 {
+		return nil, nil, fmt.Errorf("sftp password or private key is required")
+	}
+	hostKeyCallback, err := b.hostKeyCallback()
+	if err != nil {
+		return nil, nil, err
+	}
+	sshClient, err := ssh.Dial("tcp", b.cfg.Host+":"+strconv.Itoa(b.cfg.Port), &ssh.ClientConfig{
+		User:            b.cfg.Username,
+		Auth:            auth,
+		HostKeyCallback: hostKeyCallback,
+		Timeout:         15 * time.Second,
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+	client, err := sftp.NewClient(sshClient)
+	if err != nil {
+		sshClient.Close()
+		return nil, nil, err
+	}
+	return client, func() {
+		client.Close()
+		sshClient.Close()
+	}, nil
+}
+
+func (b sftpStorageBackend) hostKeyCallback() (ssh.HostKeyCallback, error) {
+	if strings.TrimSpace(b.cfg.HostKey) == "" {
+		return ssh.InsecureIgnoreHostKey(), nil
+	}
+	key, _, _, _, err := ssh.ParseAuthorizedKey([]byte(strings.TrimSpace(b.cfg.HostKey)))
+	if err != nil {
+		return nil, fmt.Errorf("invalid sftp host public key: %w", err)
+	}
+	return ssh.FixedHostKey(key), nil
+}
+
+func (b sftpStorageBackend) remotePath(key string) string {
+	return path.Join(cleanRemoteRoot(b.cfg.RemotePath), cleanObjectKey(key))
+}