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Merge branch 'dane/sftp-cleanup' into develop

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This commit is contained in:
Dane Everitt 2021-01-10 15:14:17 -08:00
commit e0cf18299a
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GPG Key ID: EEA66103B3D71F53
10 changed files with 341 additions and 556 deletions
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6
api/sftp_endpoints.go
View File

@ -62,12 +62,6 @@ func (r *Request) ValidateSftpCredentials(request SftpAuthRequest) (*SftpAuthRes
e := resp.Error()
if e != nil {
if resp.StatusCode >= 400 && resp.StatusCode < 500 {
log.WithFields(log.Fields{
"subsystem": "sftp",
"username": request.User,
"ip": request.IP,
}).Warn(e.Error())
return nil, &sftpInvalidCredentialsError{}
}

4
cmd/root.go
View File

@ -272,8 +272,8 @@ func rootCmdRun(cmd *cobra.Command, _ []string) {
// Wait until all of the servers are ready to go before we fire up the SFTP and HTTP servers.
pool.StopWait()
// Initialize the SFTP server.
if err := sftp.Initialize(c.System); err != nil {
// Run the SFTP server.
if err := sftp.New().Run(); err != nil {
log.WithError(err).Fatal("failed to initialize the sftp server")
return
}

6
server/filesystem/errors.go
View File

@ -49,10 +49,8 @@ func (e *Error) Code() ErrorCode {
// Checks if the given error is one of the Filesystem errors.
func IsFilesystemError(err error) (*Error, bool) {
if e := errors.Unwrap(err); e != nil {
err = e
}
if fserr, ok := err.(*Error); ok {
var fserr *Error
if errors.As(err, &fserr) {
return fserr, true
}
return nil, false

66
server/filesystem/filesystem.go
View File

@ -2,11 +2,6 @@ package filesystem
import (
"bufio"
"emperror.dev/errors"
"github.com/gabriel-vasile/mimetype"
"github.com/karrick/godirwalk"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/system"
"io"
"io/ioutil"
"os"
@ -17,6 +12,12 @@ import (
"strings"
"sync"
"time"
"emperror.dev/errors"
"github.com/gabriel-vasile/mimetype"
"github.com/karrick/godirwalk"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/system"
)
type Filesystem struct {
@ -71,6 +72,41 @@ func (fs *Filesystem) File(p string) (*os.File, os.FileInfo, error) {
return f, st, nil
}
// Acts by creating the given file and path on the disk if it is not present already. If
// it is present, the file is opened using the defaults which will truncate the contents.
// The opened file is then returned to the caller.
func (fs *Filesystem) Touch(p string, flag int) (*os.File, error) {
cleaned, err := fs.SafePath(p)
if err != nil {
return nil, err
}
f, err := os.OpenFile(cleaned, flag, 0644)
if err == nil {
return f, nil
}
// If the error is not because it doesn't exist then we just need to bail at this point.
if !errors.Is(err, os.ErrNotExist) {
return nil, err
}
// Create the path leading up to the file we're trying to create, setting the final perms
// on it as we go.
if err := os.MkdirAll(filepath.Dir(cleaned), 0755); err != nil {
return nil, err
}
if err := fs.Chown(filepath.Dir(cleaned)); err != nil {
return nil, err
}
o := &fileOpener{}
// Try to open the file now that we have created the pathing necessary for it, and then
// Chown that file so that the permissions don't mess with things.
f, err = o.open(cleaned, flag, 0644)
if err != nil {
return nil, err
}
_ = fs.Chown(cleaned)
return f, nil
}
// Reads a file on the system and returns it as a byte representation in a file
// reader. This is not the most memory efficient usage since it will be reading the
// entirety of the file into memory.
@ -112,22 +148,9 @@ func (fs *Filesystem) Writefile(p string, r io.Reader) error {
return err
}
// If we were unable to stat the location because it did not exist, go ahead and create
// it now. We do this after checking the disk space so that we do not just create empty
// directories at random.
if err != nil {
if err := os.MkdirAll(filepath.Dir(cleaned), 0755); err != nil {
return err
}
if err := fs.Chown(filepath.Dir(cleaned)); err != nil {
return err
}
}
o := &fileOpener{}
// This will either create the file if it does not already exist, or open and
// truncate the existing file.
file, err := o.open(cleaned, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
// Touch the file and return the handle to it at this point. This will create the file
// and any necessary directories as needed.
file, err := fs.Touch(cleaned, os.O_RDWR|os.O_CREATE|os.O_TRUNC)
if err != nil {
return err
}
@ -150,7 +173,6 @@ func (fs *Filesystem) CreateDirectory(name string, p string) error {
if err != nil {
return err
}
return os.MkdirAll(cleaned, 0755)
}

2
server/listeners.go
View File

@ -136,7 +136,7 @@ func (s *Server) StartEventListeners() {
}
}
s.Log().Info("registering event listeners: console, state, resources...")
s.Log().Debug("registering event listeners: console, state, resources...")
s.Environment.Events().On(environment.ConsoleOutputEvent, &console)
s.Environment.Events().On(environment.StateChangeEvent, &state)
s.Environment.Events().On(environment.ResourceEvent, &stats)

19
sftp/errors.go
View File

@ -1,19 +0,0 @@
package sftp
type fxerr uint32
const (
// Extends the default SFTP server to return a quota exceeded error to the client.
//
// @see https://tools.ietf.org/id/draft-ietf-secsh-filexfer-13.txt
ErrSshQuotaExceeded = fxerr(15)
)
func (e fxerr) Error() string {
switch e {
case ErrSshQuotaExceeded:
return "Quota Exceeded"
default:
return "Failure"
}
}

418
sftp/handler.go
View File

@ -5,31 +5,17 @@ import (
"io/ioutil"
"os"
"path/filepath"
"strings"
"sync"
"emperror.dev/errors"
"github.com/apex/log"
"github.com/patrickmn/go-cache"
"github.com/pkg/sftp"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/server/filesystem"
"golang.org/x/crypto/ssh"
)
type FileSystem struct {
UUID string
Permissions []string
ReadOnly bool
User User
Cache *cache.Cache
PathValidator func(fs FileSystem, p string) (string, error)
HasDiskSpace func(fs FileSystem) bool
logger *log.Entry
lock sync.Mutex
}
func (fs FileSystem) buildPath(p string) (string, error) {
return fs.PathValidator(fs, p)
}
const (
PermissionFileRead = "file.read"
PermissionFileReadContent = "file.read-content"
@ -38,343 +24,269 @@ const (
PermissionFileDelete = "file.delete"
)
type Handler struct {
permissions []string
mu sync.Mutex
fs *filesystem.Filesystem
logger *log.Entry
ro bool
}
// Returns a new connection handler for the SFTP server. This allows a given user
// to access the underlying filesystem.
func NewHandler(sc *ssh.ServerConn, fs *filesystem.Filesystem) *Handler {
return &Handler{
fs: fs,
ro: config.Get().System.Sftp.ReadOnly,
permissions: strings.Split(sc.Permissions.Extensions["permissions"], ","),
logger: log.WithFields(log.Fields{
"subsystem": "sftp",
"username": sc.User(),
"ip": sc.RemoteAddr(),
}),
}
}
// Returns the sftp.Handlers for this struct.
func (h *Handler) Handlers() sftp.Handlers {
return sftp.Handlers{
FileGet: h,
FilePut: h,
FileCmd: h,
FileList: h,
}
}
// Fileread creates a reader for a file on the system and returns the reader back.
func (fs FileSystem) Fileread(request *sftp.Request) (io.ReaderAt, error) {
func (h *Handler) Fileread(request *sftp.Request) (io.ReaderAt, error) {
// Check first if the user can actually open and view a file. This permission is named
// really poorly, but it is checking if they can read. There is an addition permission,
// "save-files" which determines if they can write that file.
if !fs.can(PermissionFileReadContent) {
return nil, sftp.ErrSshFxPermissionDenied
if !h.can(PermissionFileReadContent) {
return nil, sftp.ErrSSHFxPermissionDenied
}
p, err := fs.buildPath(request.Filepath)
h.mu.Lock()
defer h.mu.Unlock()
f, _, err := h.fs.File(request.Filepath)
if err != nil {
return nil, sftp.ErrSshFxNoSuchFile
if !errors.Is(err, os.ErrNotExist) {
h.logger.WithField("error", err).Error("error processing readfile request")
return nil, sftp.ErrSSHFxFailure
}
fs.lock.Lock()
defer fs.lock.Unlock()
if _, err := os.Stat(p); os.IsNotExist(err) {
return nil, sftp.ErrSshFxNoSuchFile
} else if err != nil {
fs.logger.WithField("error", err).Error("error while processing file stat")
return nil, sftp.ErrSshFxFailure
return nil, sftp.ErrSSHFxNoSuchFile
}
file, err := os.Open(p)
if err != nil {
fs.logger.WithField("source", p).WithField("error", err).Error("could not open file for reading")
return nil, sftp.ErrSshFxFailure
}
return file, nil
return f, nil
}
// Filewrite handles the write actions for a file on the system.
func (fs FileSystem) Filewrite(request *sftp.Request) (io.WriterAt, error) {
if fs.ReadOnly {
return nil, sftp.ErrSshFxOpUnsupported
func (h *Handler) Filewrite(request *sftp.Request) (io.WriterAt, error) {
if h.ro {
return nil, sftp.ErrSSHFxOpUnsupported
}
p, err := fs.buildPath(request.Filepath)
if err != nil {
return nil, sftp.ErrSshFxNoSuchFile
}
l := fs.logger.WithField("source", p)
l := h.logger.WithField("source", request.Filepath)
// If the user doesn't have enough space left on the server it should respond with an
// error since we won't be letting them write this file to the disk.
if !fs.HasDiskSpace(fs) {
return nil, ErrSshQuotaExceeded
if !h.fs.HasSpaceAvailable(true) {
return nil, ErrSSHQuotaExceeded
}
fs.lock.Lock()
defer fs.lock.Unlock()
stat, statErr := os.Stat(p)
// If the file doesn't exist we need to create it, as well as the directory pathway
// leading up to where that file will be created.
if os.IsNotExist(statErr) {
// This is a different pathway than just editing an existing file. If it doesn't exist already
// we need to determine if this user has permission to create files.
if !fs.can(PermissionFileCreate) {
return nil, sftp.ErrSshFxPermissionDenied
h.mu.Lock()
defer h.mu.Unlock()
// The specific permission required to perform this action. If the file exists on the
// system already it only needs to be an update, otherwise we'll check for a create.
permission := PermissionFileUpdate
_, sterr := h.fs.Stat(request.Filepath)
if sterr != nil {
if !errors.Is(sterr, os.ErrNotExist) {
l.WithField("error", sterr).Error("error while getting file reader")
return nil, sftp.ErrSSHFxFailure
}
// Create all of the directories leading up to the location where this file is being created.
if err := os.MkdirAll(filepath.Dir(p), 0755); err != nil {
l.WithFields(log.Fields{
"path": filepath.Dir(p),
"error": err,
}).Error("error making path for file")
return nil, sftp.ErrSshFxFailure
permission = PermissionFileCreate
}
file, err := os.Create(p)
// Confirm the user has permission to perform this action BEFORE calling Touch, otherwise
// you'll potentially create a file on the system and then fail out because of user
// permission checking after the fact.
if !h.can(permission) {
return nil, sftp.ErrSSHFxPermissionDenied
}
f, err := h.fs.Touch(request.Filepath, os.O_RDWR|os.O_CREATE|os.O_TRUNC)
if err != nil {
l.WithField("error", err).Error("failed to create file")
return nil, sftp.ErrSshFxFailure
}
// Not failing here is intentional. We still made the file, it is just owned incorrectly
// and will likely cause some issues.
if err := os.Chown(p, fs.User.Uid, fs.User.Gid); err != nil {
l.WithField("error", err).Warn("failed to set permissions on file")
}
return file, nil
}
// If the stat error isn't about the file not existing, there is some other issue
// at play and we need to go ahead and bail out of the process.
if statErr != nil {
l.WithField("error", statErr).Error("encountered error performing file stat")
return nil, sftp.ErrSshFxFailure
}
// If we've made it here it means the file already exists and we don't need to do anything
// fancy to handle it. Just pass over the request flags so the system knows what the end
// goal with the file is going to be.
//
// But first, check that the user has permission to save modified files.
if !fs.can(PermissionFileUpdate) {
return nil, sftp.ErrSshFxPermissionDenied
}
// Not sure this would ever happen, but lets not find out.
if stat.IsDir() {
return nil, sftp.ErrSshFxOpUnsupported
}
file, err := os.Create(p)
if err != nil {
// Prevent errors if the file is deleted between the stat and this call.
if os.IsNotExist(err) {
return nil, sftp.ErrSSHFxNoSuchFile
}
l.WithField("flags", request.Flags).WithField("error", err).Error("failed to open existing file on system")
return nil, sftp.ErrSshFxFailure
return nil, sftp.ErrSSHFxFailure
}
// Not failing here is intentional. We still made the file, it is just owned incorrectly
// and will likely cause some issues.
if err := os.Chown(p, fs.User.Uid, fs.User.Gid); err != nil {
l.WithField("error", err).Warn("error chowning file")
}
return file, nil
return f, nil
}
// Filecmd hander for basic SFTP system calls related to files, but not anything to do with reading
// or writing to those files.
func (fs FileSystem) Filecmd(request *sftp.Request) error {
if fs.ReadOnly {
return sftp.ErrSshFxOpUnsupported
func (h *Handler) Filecmd(request *sftp.Request) error {
if h.ro {
return sftp.ErrSSHFxOpUnsupported
}
p, err := fs.buildPath(request.Filepath)
if err != nil {
return sftp.ErrSshFxNoSuchFile
}
l := fs.logger.WithField("source", p)
var target string
// If a target is provided in this request validate that it is going to the correct
// location for the server. If it is not, return an operation unsupported error. This
// is maybe not the best error response, but its not wrong either.
l := h.logger.WithField("source", request.Filepath)
if request.Target != "" {
target, err = fs.buildPath(request.Target)
if err != nil {
return sftp.ErrSshFxOpUnsupported
}
l = l.WithField("target", request.Target)
}
switch request.Method {
// Allows a user to make changes to the permissions of a given file or directory
// on their server using their SFTP client.
case "Setstat":
if !fs.can(PermissionFileUpdate) {
return sftp.ErrSshFxPermissionDenied
if !h.can(PermissionFileUpdate) {
return sftp.ErrSSHFxPermissionDenied
}
mode := os.FileMode(0644)
// If the client passed a valid file permission use that, otherwise use the
// default of 0644 set above.
if request.Attributes().FileMode().Perm() != 0000 {
mode = request.Attributes().FileMode().Perm()
mode := request.Attributes().FileMode().Perm()
// If the client passes an invalid FileMode just use the default 0644.
if mode == 0000 {
mode = os.FileMode(0644)
}
// Force directories to be 0755
// Force directories to be 0755.
if request.Attributes().FileMode().IsDir() {
mode = 0755
}
if err := os.Chmod(p, mode); err != nil {
if os.IsNotExist(err) {
if err := h.fs.Chmod(request.Filepath, mode); err != nil {
if errors.Is(err, os.ErrNotExist) {
return sftp.ErrSSHFxNoSuchFile
}
l.WithField("error", err).Error("failed to perform setstat on item")
return sftp.ErrSSHFxFailure
}
return nil
break
// Support renaming a file (aka Move).
case "Rename":
if !fs.can(PermissionFileUpdate) {
if !h.can(PermissionFileUpdate) {
return sftp.ErrSSHFxPermissionDenied
}
if err := os.Rename(p, target); err != nil {
if os.IsNotExist(err) {
if err := h.fs.Rename(request.Filepath, request.Target); err != nil {
if errors.Is(err, os.ErrNotExist) {
return sftp.ErrSSHFxNoSuchFile
}
l.WithField("target", target).WithField("error", err).Error("failed to rename file")
return sftp.ErrSshFxFailure
l.WithField("error", err).Error("failed to rename file")
return sftp.ErrSSHFxFailure
}
break
// Handle deletion of a directory. This will properly delete all of the files and
// folders within that directory if it is not already empty (unlike a lot of SFTP
// clients that must delete each file individually).
case "Rmdir":
if !fs.can(PermissionFileDelete) {
return sftp.ErrSshFxPermissionDenied
if !h.can(PermissionFileDelete) {
return sftp.ErrSSHFxPermissionDenied
}
if err := os.RemoveAll(p); err != nil {
if err := h.fs.Delete(request.Filepath); err != nil {
l.WithField("error", err).Error("failed to remove directory")
return sftp.ErrSshFxFailure
return sftp.ErrSSHFxFailure
}
return sftp.ErrSshFxOk
return sftp.ErrSSHFxOk
// Handle requests to create a new Directory.
case "Mkdir":
if !fs.can(PermissionFileCreate) {
return sftp.ErrSshFxPermissionDenied
if !h.can(PermissionFileCreate) {
return sftp.ErrSSHFxPermissionDenied
}
if err := os.MkdirAll(p, 0755); err != nil {
name := strings.Split(filepath.Clean(request.Filepath), "/")
err := h.fs.CreateDirectory(name[len(name)-1], strings.Join(name[0:len(name)-1], "/"))
if err != nil {
l.WithField("error", err).Error("failed to create directory")
return sftp.ErrSshFxFailure
return sftp.ErrSSHFxFailure
}
break
// Support creating symlinks between files. The source and target must resolve within
// the server home directory.
case "Symlink":
if !fs.can(PermissionFileCreate) {
return sftp.ErrSshFxPermissionDenied
if !h.can(PermissionFileCreate) {
return sftp.ErrSSHFxPermissionDenied
}
if err := os.Symlink(p, target); err != nil {
l.WithField("target", target).WithField("error", err).Error("failed to create symlink")
return sftp.ErrSshFxFailure
}
break
case "Remove":
if !fs.can(PermissionFileDelete) {
return sftp.ErrSshFxPermissionDenied
}
if err := os.Remove(p); err != nil {
if os.IsNotExist(err) {
source, err := h.fs.SafePath(request.Filepath)
if err != nil {
return sftp.ErrSSHFxNoSuchFile
}
target, err := h.fs.SafePath(request.Target)
if err != nil {
return sftp.ErrSSHFxNoSuchFile
}
if err := os.Symlink(source, target); err != nil {
l.WithField("target", target).WithField("error", err).Error("failed to create symlink")
return sftp.ErrSSHFxFailure
}
break
// Called when deleting a file.
case "Remove":
if !h.can(PermissionFileDelete) {
return sftp.ErrSSHFxPermissionDenied
}
if err := h.fs.Delete(request.Filepath); err != nil {
if errors.Is(err, os.ErrNotExist) {
return sftp.ErrSSHFxNoSuchFile
}
l.WithField("error", err).Error("failed to remove a file")
return sftp.ErrSshFxFailure
return sftp.ErrSSHFxFailure
}
return sftp.ErrSshFxOk
return sftp.ErrSSHFxOk
default:
return sftp.ErrSshFxOpUnsupported
return sftp.ErrSSHFxOpUnsupported
}
var fileLocation = p
if target != "" {
fileLocation = target
target := request.Filepath
if request.Target != "" {
target = request.Target
}
// Not failing here is intentional. We still made the file, it is just owned incorrectly
// and will likely cause some issues. There is no logical check for if the file was removed
// because both of those cases (Rmdir, Remove) have an explicit return rather than break.
if err := os.Chown(fileLocation, fs.User.Uid, fs.User.Gid); err != nil {
if err := h.fs.Chown(target); err != nil {
l.WithField("error", err).Warn("error chowning file")
}
return sftp.ErrSshFxOk
return sftp.ErrSSHFxOk
}
// Filelist is the handler for SFTP filesystem list calls. This will handle calls to list the contents of
// a directory as well as perform file/folder stat calls.
func (fs FileSystem) Filelist(request *sftp.Request) (sftp.ListerAt, error) {
p, err := fs.buildPath(request.Filepath)
if err != nil {
return nil, sftp.ErrSshFxNoSuchFile
func (h *Handler) Filelist(request *sftp.Request) (sftp.ListerAt, error) {
if !h.can(PermissionFileRead) {
return nil, sftp.ErrSSHFxPermissionDenied
}
switch request.Method {
case "List":
if !fs.can(PermissionFileRead) {
return nil, sftp.ErrSshFxPermissionDenied
p, err := h.fs.SafePath(request.Filepath)
if err != nil {
return nil, sftp.ErrSSHFxNoSuchFile
}
files, err := ioutil.ReadDir(p)
if err != nil {
fs.logger.WithField("error", err).Error("error while listing directory")
h.logger.WithField("source", request.Filepath).WithField("error", err).Error("error while listing directory")
return nil, sftp.ErrSshFxFailure
return nil, sftp.ErrSSHFxFailure
}
return ListerAt(files), nil
case "Stat":
if !fs.can(PermissionFileRead) {
return nil, sftp.ErrSshFxPermissionDenied
st, err := h.fs.Stat(request.Filepath)
if err != nil {
if errors.Is(err, os.ErrNotExist) {
return nil, sftp.ErrSSHFxNoSuchFile
}
s, err := os.Stat(p)
if os.IsNotExist(err) {
return nil, sftp.ErrSshFxNoSuchFile
} else if err != nil {
fs.logger.WithField("source", p).WithField("error", err).Error("error performing stat on file")
return nil, sftp.ErrSshFxFailure
h.logger.WithField("source", request.Filepath).WithField("error", err).Error("error performing stat on file")
return nil, sftp.ErrSSHFxFailure
}
return ListerAt([]os.FileInfo{s}), nil
return ListerAt([]os.FileInfo{st.Info}), nil
default:
// Before adding readlink support we need to evaluate any potential security risks
// as a result of navigating around to a location that is outside the home directory
// for the logged in user. I don't foresee it being much of a problem, but I do want to
// check it out before slapping some code here. Until then, we'll just return an
// unsupported response code.
return nil, sftp.ErrSshFxOpUnsupported
return nil, sftp.ErrSSHFxOpUnsupported
}
}
// Determines if a user has permission to perform a specific action on the SFTP server. These
// permissions are defined and returned by the Panel API.
func (fs FileSystem) can(permission string) bool {
// Server owners and super admins have their permissions returned as '[*]' via the Panel
func (h *Handler) can(permission string) bool {
// SFTPServer owners and super admins have their permissions returned as '[*]' via the Panel
// API, so for the sake of speed do an initial check for that before iterating over the
// entire array of permissions.
if len(fs.Permissions) == 1 && fs.Permissions[0] == "*" {
if len(h.permissions) == 1 && h.permissions[0] == "*" {
return true
}
// Not the owner or an admin, loop over the permissions that were returned to determine
// if they have the passed permission.
for _, p := range fs.Permissions {
for _, p := range h.permissions {
if p == permission {
return true
}
}
return false
}

337
sftp/server.go
View File

@ -5,74 +5,185 @@ import (
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"path"
"strconv"
"strings"
"time"
"emperror.dev/errors"
"github.com/apex/log"
"github.com/patrickmn/go-cache"
"github.com/pkg/sftp"
"github.com/pterodactyl/wings/api"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/server"
"golang.org/x/crypto/ssh"
)
type Settings struct {
//goland:noinspection GoNameStartsWithPackageName
type SFTPServer struct {
BasePath string
ReadOnly bool
BindPort int
BindAddress string
Listen string
}
type User struct {
Uid int
Gid int
func New() *SFTPServer {
cfg := config.Get().System
return &SFTPServer{
BasePath: cfg.Data,
ReadOnly: cfg.Sftp.ReadOnly,
Listen: cfg.Sftp.Address + ":" + strconv.Itoa(cfg.Sftp.Port),
}
}
type Server struct {
cache *cache.Cache
// Starts the SFTP server and add a persistent listener to handle inbound SFTP connections.
func (c *SFTPServer) Run() error {
if _, err := os.Stat(path.Join(c.BasePath, ".sftp/id_rsa")); os.IsNotExist(err) {
if err := c.generatePrivateKey(); err != nil {
return err
}
} else if err != nil {
return errors.Wrap(err, "sftp/server: could not stat private key file")
}
pb, err := ioutil.ReadFile(path.Join(c.BasePath, ".sftp/id_rsa"))
if err != nil {
return errors.Wrap(err, "sftp/server: could not read private key file")
}
private, err := ssh.ParsePrivateKey(pb)
if err != nil {
return err
}
Settings Settings
User User
PathValidator func(fs FileSystem, p string) (string, error)
DiskSpaceValidator func(fs FileSystem) bool
// Validator function that is called when a user connects to the server. This should
// check against whatever system is desired to confirm if the given username and password
// combination is valid. If so, should return an authentication response.
CredentialValidator func(r api.SftpAuthRequest) (*api.SftpAuthResponse, error)
}
// Create a new server configuration instance.
func New(c *Server) error {
c.cache = cache.New(5*time.Minute, 10*time.Minute)
return nil
}
// Initialize the SFTP server and add a persistent listener to handle inbound SFTP connections.
func (c *Server) Initialize() error {
serverConfig := &ssh.ServerConfig{
conf := &ssh.ServerConfig{
NoClientAuth: false,
MaxAuthTries: 6,
PasswordCallback: func(conn ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
resp, err := c.CredentialValidator(api.SftpAuthRequest{
PasswordCallback: c.passwordCallback,
}
conf.AddHostKey(private)
listener, err := net.Listen("tcp", c.Listen)
if err != nil {
return err
}
log.WithField("listen", c.Listen).Info("sftp server listening for connections")
for {
if conn, _ := listener.Accept(); conn != nil {
go func(conn net.Conn) {
defer conn.Close()
c.AcceptInbound(conn, conf)
}(conn)
}
}
}
// Handles an inbound connection to the instance and determines if we should serve the
// request or not.
func (c SFTPServer) AcceptInbound(conn net.Conn, config *ssh.ServerConfig) {
// Before beginning a handshake must be performed on the incoming net.Conn
sconn, chans, reqs, err := ssh.NewServerConn(conn, config)
if err != nil {
return
}
defer sconn.Close()
go ssh.DiscardRequests(reqs)
for ch := range chans {
// If its not a session channel we just move on because its not something we
// know how to handle at this point.
if ch.ChannelType() != "session" {
ch.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel, requests, err := ch.Accept()
if err != nil {
continue
}
go func(in <-chan *ssh.Request) {
for req := range in {
// Channels have a type that is dependent on the protocol. For SFTP
// this is "subsystem" with a payload that (should) be "sftp". Discard
// anything else we receive ("pty", "shell", etc)
req.Reply(req.Type == "subsystem" && string(req.Payload[4:]) == "sftp", nil)
}
}(requests)
// If no UUID has been set on this inbound request then we can assume we
// have screwed up something in the authentication code. This is a sanity
// check, but should never be encountered (ideally...).
//
// This will also attempt to match a specific server out of the global server
// store and return nil if there is no match.
uuid := sconn.Permissions.Extensions["uuid"]
srv := server.GetServers().Find(func(s *server.Server) bool {
if uuid == "" {
return false
}
return s.Id() == uuid
})
if srv == nil {
continue
}
// Spin up a SFTP server instance for the authenticated user's server allowing
// them access to the underlying filesystem.
handler := sftp.NewRequestServer(channel, NewHandler(sconn, srv.Filesystem()).Handlers())
if err := handler.Serve(); err == io.EOF {
handler.Close()
}
}
}
// Generates a private key that will be used by the SFTP server.
func (c *SFTPServer) generatePrivateKey() error {
key, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
return errors.WithStack(err)
}
if err := os.MkdirAll(path.Join(c.BasePath, ".sftp"), 0755); err != nil {
return errors.Wrap(err, "sftp/server: could not create .sftp directory")
}
o, err := os.OpenFile(path.Join(c.BasePath, ".sftp/id_rsa"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return errors.WithStack(err)
}
defer o.Close()
err = pem.Encode(o, &pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: x509.MarshalPKCS1PrivateKey(key),
})
return errors.WithStack(err)
}
// A function capable of validating user credentials with the Panel API.
func (c *SFTPServer) passwordCallback(conn ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
request := api.SftpAuthRequest{
User: conn.User(),
Pass: string(pass),
IP: conn.RemoteAddr().String(),
SessionID: conn.SessionID(),
ClientVersion: conn.ClientVersion(),
})
}
logger := log.WithFields(log.Fields{"subsystem": "sftp", "username": conn.User(), "ip": conn.RemoteAddr().String()})
logger.Debug("validating credentials for SFTP connection")
resp, err := api.New().ValidateSftpCredentials(request)
if err != nil {
if api.IsInvalidCredentialsError(err) {
logger.Warn("failed to validate user credentials (invalid username or password)")
} else {
logger.WithField("error", err).Error("encountered an error while trying to validate user credentials")
}
return nil, err
}
logger.WithField("server", resp.Server).Debug("credentials validated and matched to server instance")
sshPerm := &ssh.Permissions{
Extensions: map[string]string{
"uuid": resp.Server,
@ -82,158 +193,4 @@ func (c *Server) Initialize() error {
}
return sshPerm, nil
},
}
if _, err := os.Stat(path.Join(c.Settings.BasePath, ".sftp/id_rsa")); os.IsNotExist(err) {
if err := c.generatePrivateKey(); err != nil {
return err
}
} else if err != nil {
return err
}
privateBytes, err := ioutil.ReadFile(path.Join(c.Settings.BasePath, ".sftp/id_rsa"))
if err != nil {
return err
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
return err
}
// Add our private key to the server configuration.
serverConfig.AddHostKey(private)
listener, err := net.Listen("tcp", fmt.Sprintf("%s:%d", c.Settings.BindAddress, c.Settings.BindPort))
if err != nil {
return err
}
log.WithField("host", c.Settings.BindAddress).WithField("port", c.Settings.BindPort).Info("sftp subsystem listening for connections")
for {
conn, _ := listener.Accept()
if conn != nil {
go c.AcceptInboundConnection(conn, serverConfig)
}
}
}
// Handles an inbound connection to the instance and determines if we should serve the request
// or not.
func (c Server) AcceptInboundConnection(conn net.Conn, config *ssh.ServerConfig) {
defer conn.Close()
// Before beginning a handshake must be performed on the incoming net.Conn
sconn, chans, reqs, err := ssh.NewServerConn(conn, config)
if err != nil {
return
}
defer sconn.Close()
go ssh.DiscardRequests(reqs)
for newChannel := range chans {
// If its not a session channel we just move on because its not something we
// know how to handle at this point.
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
continue
}
// Channels have a type that is dependent on the protocol. For SFTP this is "subsystem"
// with a payload that (should) be "sftp". Discard anything else we receive ("pty", "shell", etc)
go func(in <-chan *ssh.Request) {
for req := range in {
ok := false
switch req.Type {
case "subsystem":
if string(req.Payload[4:]) == "sftp" {
ok = true
}
}
req.Reply(ok, nil)
}
}(requests)
// Configure the user's home folder for the rest of the request cycle.
if sconn.Permissions.Extensions["uuid"] == "" {
continue
}
// Create a new handler for the currently logged in user's server.
fs := c.createHandler(sconn)
// Create the server instance for the channel using the filesystem we created above.
server := sftp.NewRequestServer(channel, fs)
if err := server.Serve(); err == io.EOF {
server.Close()
}
}
}
// Creates a new SFTP handler for a given server. The directory argument should
// be the base directory for a server. All actions done on the server will be
// relative to that directory, and the user will not be able to escape out of it.
func (c Server) createHandler(sc *ssh.ServerConn) sftp.Handlers {
p := FileSystem{
UUID: sc.Permissions.Extensions["uuid"],
Permissions: strings.Split(sc.Permissions.Extensions["permissions"], ","),
ReadOnly: c.Settings.ReadOnly,
Cache: c.cache,
User: c.User,
HasDiskSpace: c.DiskSpaceValidator,
PathValidator: c.PathValidator,
logger: log.WithFields(log.Fields{
"subsystem": "sftp",
"username": sc.User(),
"ip": sc.RemoteAddr(),
}),
}
return sftp.Handlers{
FileGet: p,
FilePut: p,
FileCmd: p,
FileList: p,
}
}
// Generates a private key that will be used by the SFTP server.
func (c Server) generatePrivateKey() error {
key, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
return err
}
if err := os.MkdirAll(path.Join(c.Settings.BasePath, ".sftp"), 0755); err != nil {
return err
}
o, err := os.OpenFile(path.Join(c.Settings.BasePath, ".sftp/id_rsa"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return err
}
defer o.Close()
pkey := &pem.Block{
Type: "RSA PRIVATE KEY",
Bytes: x509.MarshalPKCS1PrivateKey(key),
}
if err := pem.Encode(o, pkey); err != nil {
return err
}
return nil
}

97
sftp/sftp.go
View File

@ -1,97 +0,0 @@
package sftp
import (
"emperror.dev/errors"
"github.com/apex/log"
"github.com/pterodactyl/wings/api"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/server"
)
var noMatchingServerError = errors.New("no matching server with that UUID was found")
func Initialize(config config.SystemConfiguration) error {
s := &Server{
User: User{
Uid: config.User.Uid,
Gid: config.User.Gid,
},
Settings: Settings{
BasePath: config.Data,
ReadOnly: config.Sftp.ReadOnly,
BindAddress: config.Sftp.Address,
BindPort: config.Sftp.Port,
},
CredentialValidator: validateCredentials,
PathValidator: validatePath,
DiskSpaceValidator: validateDiskSpace,
}
if err := New(s); err != nil {
return err
}
// Initialize the SFTP server in a background thread since this is
// a long running operation.
go func(s *Server) {
if err := s.Initialize(); err != nil {
log.WithField("subsystem", "sftp").WithField("error", err).Error("failed to initialize SFTP subsystem")
}
}(s)
return nil
}
func validatePath(fs FileSystem, p string) (string, error) {
s := server.GetServers().Find(func(server *server.Server) bool {
return server.Id() == fs.UUID
})
if s == nil {
return "", noMatchingServerError
}
return s.Filesystem().SafePath(p)
}
func validateDiskSpace(fs FileSystem) bool {
s := server.GetServers().Find(func(server *server.Server) bool {
return server.Id() == fs.UUID
})
if s == nil {
return false
}
return s.Filesystem().HasSpaceAvailable(true)
}
// Validates a set of credentials for a SFTP login against Pterodactyl Panel and returns
// the server's UUID if the credentials were valid.
func validateCredentials(c api.SftpAuthRequest) (*api.SftpAuthResponse, error) {
f := log.Fields{"subsystem": "sftp", "username": c.User, "ip": c.IP}
log.WithFields(f).Debug("validating credentials for SFTP connection")
resp, err := api.New().ValidateSftpCredentials(c)
if err != nil {
if api.IsInvalidCredentialsError(err) {
log.WithFields(f).Warn("failed to validate user credentials (invalid username or password)")
} else {
log.WithFields(f).Error("encountered an error while trying to validate user credentials")
}
return resp, err
}
s := server.GetServers().Find(func(server *server.Server) bool {
return server.Id() == resp.Server
})
if s == nil {
return resp, noMatchingServerError
}
s.Log().WithFields(f).Debug("credentials successfully validated and matched user to server instance")
return resp, err
}

18
sftp/lister.go → sftp/utils.go
View File

@ -5,6 +5,13 @@ import (
"os"
)
const (
// Extends the default SFTP server to return a quota exceeded error to the client.
//
// @see https://tools.ietf.org/id/draft-ietf-secsh-filexfer-13.txt
ErrSSHQuotaExceeded = fxerr(15)
)
type ListerAt []os.FileInfo
// Returns the number of entries copied and an io.EOF error if we made it to the end of the file list.
@ -20,3 +27,14 @@ func (l ListerAt) ListAt(f []os.FileInfo, offset int64) (int, error) {
return n, nil
}
}
type fxerr uint32
func (e fxerr) Error() string {
switch e {
case ErrSSHQuotaExceeded:
return "Quota Exceeded"
default:
return "Failure"
}
}