package server import ( "bufio" "bytes" "encoding/json" "errors" "fmt" "github.com/gabriel-vasile/mimetype" "github.com/pterodactyl/wings/config" "go.uber.org/zap" "io" "io/ioutil" "os" "path" "path/filepath" "sort" "strconv" "strings" "sync" "time" ) // Error returned when there is a bad path provided to one of the FS calls. var InvalidPathResolution = errors.New("invalid path resolution") type Filesystem struct { // The server object associated with this Filesystem. Server *Server Configuration *config.SystemConfiguration } // Returns the root path that contains all of a server's data. func (fs *Filesystem) Path() string { return filepath.Join(fs.Configuration.Data, fs.Server.Uuid) } // Normalizes a directory being passed in to ensure the user is not able to escape // from their data directory. After normalization if the directory is still within their home // path it is returned. If they managed to "escape" an error will be returned. // // This logic is actually copied over from the SFTP server code. Ideally that eventually // either gets ported into this application, or is able to make use of this package. func (fs *Filesystem) SafePath(p string) (string, error) { var nonExistentPathResolution string // Calling filpath.Clean on the joined directory will resolve it to the absolute path, // removing any ../ type of resolution arguments, and leaving us with a direct path link. // // This will also trim the existing root path off the beginning of the path passed to // the function since that can get a bit messy. r := filepath.Clean(filepath.Join(fs.Path(), strings.TrimPrefix(p, fs.Path()))) // At the same time, evaluate the symlink status and determine where this file or folder // is truly pointing to. p, err := filepath.EvalSymlinks(r) if err != nil && !os.IsNotExist(err) { return "", err } else if os.IsNotExist(err) { // The requested directory doesn't exist, so at this point we need to iterate up the // path chain until we hit a directory that _does_ exist and can be validated. parts := strings.Split(filepath.Dir(r), "/") var try string // Range over all of the path parts and form directory pathings from the end // moving up until we have a valid resolution or we run out of paths to try. for k := range parts { try = strings.Join(parts[:(len(parts) - k)], "/") if !strings.HasPrefix(try, fs.Path()) { break } t, err := filepath.EvalSymlinks(try) if err == nil { nonExistentPathResolution = t break } } } // If the new path doesn't start with their root directory there is clearly an escape // attempt going on, and we should NOT resolve this path for them. if nonExistentPathResolution != "" { if !strings.HasPrefix(nonExistentPathResolution, fs.Path()) { return "", InvalidPathResolution } // If the nonExistentPathResoltion variable is not empty then the initial path requested // did not exist and we looped through the pathway until we found a match. At this point // we've confirmed the first matched pathway exists in the root server directory, so we // can go ahead and just return the path that was requested initially. return r, nil } // If the requested directory from EvalSymlinks begins with the server root directory go // ahead and return it. If not we'll return an error which will block any further action // on the file. if strings.HasPrefix(p, fs.Path()) { return p, nil } return "", InvalidPathResolution } // Determines if the directory a file is trying to be added to has enough space available // for the file to be written to. // // Because determining the amount of space being used by a server is a taxing operation we // will load it all up into a cache and pull from that as long as the key is not expired. func (fs *Filesystem) HasSpaceAvailable() bool { var space = fs.Server.Build.DiskSpace // If space is -1 or 0 just return true, means they're allowed unlimited. if space <= 0 { return true } var size int64 if x, exists := fs.Server.Cache.Get("disk_used"); exists { size = x.(int64) } // If there is no size its either because there is no data (in which case running this function // will have effectively no impact), or there is nothing in the cache, in which case we need to // grab the size of their data directory. This is a taxing operation, so we want to store it in // the cache once we've gotten it. if size == 0 { if size, err := fs.DirectorySize("/"); err != nil { zap.S().Warnw("failed to determine directory size", zap.String("server", fs.Server.Uuid), zap.Error(err)) } else { fs.Server.Cache.Set("disk_used", size, time.Minute*5) } } // Determine if their folder size, in bytes, is smaller than the amount of space they've // been allocated. return (size / 1024.0 / 1024.0) <= space } // Determines the directory size of a given location by running parallel tasks to iterate // through all of the folders. Returns the size in bytes. This can be a fairly taxing operation // on locations with tons of files, so it is recommended that you cache the output. func (fs *Filesystem) DirectorySize(dir string) (int64, error) { var size int64 var wg sync.WaitGroup cleaned, err := fs.SafePath(dir) if err != nil { return 0, err } files, err := ioutil.ReadDir(cleaned) if err != nil { return 0, err } // Iterate over all of the files and directories. If it is a file, immediately add its size // to the total size being returned. If we're dealing with a directory, call this function // on a seperate thread until we have gotten the size of everything nested within the given // directory. for _, f := range files { if f.IsDir() { wg.Add(1) go func(p string) { defer wg.Done() s, _ := fs.DirectorySize(p) size += s }(filepath.Join(cleaned, f.Name())) } else { size += f.Size() } } wg.Wait() return size, 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. func (fs *Filesystem) Readfile(p string) (io.Reader, error) { cleaned, err := fs.SafePath(p) if err != nil { return nil, err } b, err := ioutil.ReadFile(cleaned) if err != nil { return nil, err } return bytes.NewReader(b), nil } // Writes a file to the system. If the file does not already exist one will be created. // // @todo should probably have a write lock here so we don't write twice at once. func (fs *Filesystem) Writefile(p string, r io.Reader) error { cleaned, err := fs.SafePath(p) if err != nil { return err } // If the file does not exist on the system already go ahead and create the pathway // to it and an empty file. We'll then write to it later on after this completes. if stat, err := os.Stat(cleaned); err != nil && os.IsNotExist(err) { if err := os.MkdirAll(filepath.Dir(cleaned), 0755); err != nil { return err } if err := fs.Chown(filepath.Dir(cleaned)); err != nil { return err } } else if err != nil { return err } else if stat.IsDir() { return errors.New("cannot use a directory as a file for writing") } // This will either create the file if it does not already exist, or open and // truncate the existing file. file, err := os.OpenFile(cleaned, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644) if err != nil { return err } defer file.Close() // Create a new buffered writer that will write to the file we just opened // and stream in the contents from the reader. w := bufio.NewWriter(file) buf := make([]byte, 1024) for { n, err := r.Read(buf) if err != nil && err != io.EOF { return err } if n == 0 { break } if _, err := w.Write(buf[:n]); err != nil { return err } } if err := w.Flush(); err != nil { return err } // Finally, chown the file to ensure the permissions don't end up out-of-whack // if we had just created it. return fs.Chown(p) } // Defines the stat struct object. type Stat struct { Info os.FileInfo Mimetype string } func (s *Stat) MarshalJSON() ([]byte, error) { return json.Marshal(struct { Name string `json:"name"` Created string `json:"created"` Modified string `json:"modified"` Mode string `json:"mode"` Size int64 `json:"size"` Directory bool `json:"directory"` File bool `json:"file"` Symlink bool `json:"symlink"` Mime string `json:"mime"` }{ Name: s.Info.Name(), Created: s.CTime().String(), Modified: s.Info.ModTime().String(), Mode: s.Info.Mode().String(), Size: s.Info.Size(), Directory: s.Info.IsDir(), File: !s.Info.IsDir(), Symlink: s.Info.Mode().Perm()&os.ModeSymlink != 0, Mime: s.Mimetype, }) } // Stats a file or folder and returns the base stat object from go along with the // MIME data that can be used for editing files. func (fs *Filesystem) Stat(p string) (*Stat, error) { cleaned, err := fs.SafePath(p) if err != nil { return nil, err } s, err := os.Stat(cleaned) if err != nil { return nil, err } var m = "inode/directory" if !s.IsDir() { m, _, err = mimetype.DetectFile(cleaned) if err != nil { return nil, err } } st := &Stat{ Info: s, Mimetype: m, } return st, nil } // Creates a new directory (name) at a specificied path (p) for the server. func (fs *Filesystem) CreateDirectory(name string, p string) error { cleaned, err := fs.SafePath(path.Join(p, name)) if err != nil { return err } return os.MkdirAll(cleaned, 0755) } // Moves (or renames) a file or directory. func (fs *Filesystem) Rename(from string, to string) error { cleanedFrom, err := fs.SafePath(from) if err != nil { return err } cleanedTo, err := fs.SafePath(to) if err != nil { return err } return os.Rename(cleanedFrom, cleanedTo) } // Recursively iterates over a directory and sets the permissions on all of the // underlying files. func (fs *Filesystem) Chown(path string) error { cleaned, err := fs.SafePath(path) if err != nil { return err } if s, err := os.Stat(cleaned); err != nil { return err } else if !s.IsDir() { return os.Chown(cleaned, fs.Configuration.User.Uid, fs.Configuration.User.Gid) } return fs.chownDirectory(cleaned) } // Iterate over all of the files and directories. If it is a file just go ahead and perform // the chown operation. Otherwise dig deeper into the directory until we've run out of // directories to dig into. func (fs *Filesystem) chownDirectory(path string) error { var wg sync.WaitGroup cleaned, err := fs.SafePath(path) if err != nil { return err } files, err := ioutil.ReadDir(cleaned) if err != nil { return err } for _, f := range files { if f.IsDir() { wg.Add(1) go func(p string) { defer wg.Done() fs.chownDirectory(p) }(filepath.Join(cleaned, f.Name())) } else { os.Chown(filepath.Join(cleaned, f.Name()), fs.Configuration.User.Uid, fs.Configuration.User.Gid) } } wg.Wait() return nil } // Copies a given file to the same location and appends a suffix to the file to indicate that // it has been copied. // // @todo need to get an exclusive lock on the file. func (fs *Filesystem) Copy(p string) error { cleaned, err := fs.SafePath(p) if err != nil { return err } if s, err := os.Stat(cleaned); (err != nil && os.IsNotExist(err)) || s.IsDir() || !s.Mode().IsRegular() { // For now I think I am okay just returning a nil response if the thing // we're trying to copy doesn't exist. Probably will want to come back and // re-evaluate if this is a smart decision (I'm guessing not). return nil } else if err != nil { return err } base := filepath.Base(cleaned) relative := strings.TrimSuffix(strings.TrimPrefix(cleaned, fs.Path()), base) extension := filepath.Ext(base) name := strings.TrimSuffix(base, filepath.Ext(base)) // Begin looping up to 50 times to try and create a unique copy file name. This will take // an input of "file.txt" and generate "file copy.txt". If that name is already taken, it will // then try to write "file copy 2.txt" and so on, until reaching 50 loops. At that point we // won't waste anymore time, just use the current timestamp and make that copy. // // Could probably make this more efficient by checking if there are any files matching the copy // pattern, and trying to find the highest number and then incrementing it by one rather than // looping endlessly. var i int copySuffix := " copy" for i = 0; i < 51; i++ { if i > 0 { copySuffix = " copy " + strconv.Itoa(i) } tryName := fmt.Sprintf("%s%s%s", name, copySuffix, extension) tryLocation, err := fs.SafePath(path.Join(relative, tryName)) if err != nil { return err } // If the file exists, continue to the next loop, otherwise we're good to start a copy. if _, err := os.Stat(tryLocation); err != nil && !os.IsNotExist(err) { return err } else if os.IsNotExist(err) { break } if i == 50 { copySuffix = "." + time.Now().Format(time.RFC3339) } } finalPath, err := fs.SafePath(path.Join(relative, fmt.Sprintf("%s%s%s", name, copySuffix, extension))) if err != nil { return err } source, err := os.Open(cleaned) if err != nil { return err } defer source.Close() dest, err := os.Create(finalPath) if err != nil { return err } defer dest.Close() if _, err := io.Copy(dest, source); err != nil { return err } return nil } // Deletes a file or folder from the system. Prevents the user from accidentally // (or maliciously) removing their root server data directory. func (fs *Filesystem) Delete(p string) error { cleaned, err := fs.SafePath(p) if err != nil { return err } // Block any whoopsies. if cleaned == fs.Path() { return errors.New("cannot delete root server directory") } return os.RemoveAll(cleaned) } // Lists the contents of a given directory and returns stat information about each // file and folder within it. func (fs *Filesystem) ListDirectory(p string) ([]*Stat, error) { cleaned, err := fs.SafePath(p) if err != nil { return nil, err } files, err := ioutil.ReadDir(cleaned) if err != nil { return nil, err } var wg sync.WaitGroup // You must initialize the output of this directory as a non-nil value otherwise // when it is marshaled into a JSON object you'll just get 'null' back, which will // break the panel badly. out := make([]*Stat, 0) // Iterate over all of the files and directories returned and perform an async process // to get the mime-type for them all. for _, file := range files { wg.Add(1) go func(f os.FileInfo) { defer wg.Done() var m = "inode/directory" if !f.IsDir() { m, _, _ = mimetype.DetectFile(filepath.Join(cleaned, f.Name())) } out = append(out, &Stat{ Info: f, Mimetype: m, }) }(file) } wg.Wait() // Sort the output alphabetically to begin with since we've run the output // through an asynchronous process and the order is gonna be very random. sort.SliceStable(out, func(i, j int) bool { if out[i].Info.Name() == out[j].Info.Name() || out[i].Info.Name() > out[j].Info.Name() { return true } return false }) // Then, sort it so that directories are listed first in the output. Everything // will continue to be alphabetized at this point. sort.SliceStable(out, func(i, j int) bool { return out[i].Info.IsDir() }) return out, nil }