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Minor improvements to logic around decompression

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This commit is contained in:
Dane Everitt 2021-01-16 11:48:30 -08:00
parent b17cf5b93d
commit 67ecbd667a
No known key found for this signature in database
GPG Key ID: EEA66103B3D71F53
5 changed files with 102 additions and 77 deletions
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2
router/middleware/middleware.go
View File

@ -130,7 +130,7 @@ func (re *RequestError) asFilesystemError() (int, string) {
return http.StatusBadRequest, "Cannot perform that action: file is a directory."
}
if filesystem.IsErrorCode(err, filesystem.ErrCodeDiskSpace) || strings.Contains(err.Error(), "filesystem: not enough disk space") {
return http.StatusBadRequest, "Cannot perform that action: file is a directory."
return http.StatusBadRequest, "There is not enough disk space available to perform that action."
}
if strings.HasSuffix(err.Error(), "file name too long") {
return http.StatusBadRequest, "Cannot perform that action: file name is too long."

26
router/router_server_files.go
View File

@ -380,7 +380,8 @@ func postServerCompressFiles(c *gin.Context) {
// of unpacking an archive that exists on the server into the provided RootPath
// for the server.
func postServerDecompressFiles(c *gin.Context) {
s := ExtractServer(c)
s := middleware.ExtractServer(c)
lg := middleware.ExtractLogger(c)
var data struct {
RootPath string `json:"root"`
File string `json:"file"`
@ -389,12 +390,12 @@ func postServerDecompressFiles(c *gin.Context) {
return
}
lg := s.Log().WithFields(log.Fields{"root_path": data.RootPath, "file": data.File})
lg.Debug("checking if space is available for decompression")
hasSpace, err := s.Filesystem().SpaceAvailableForDecompression(data.RootPath, data.File)
lg = lg.WithFields(log.Fields{"root_path": data.RootPath, "file": data.File})
lg.Debug("checking if space is available for file decompression")
err := s.Filesystem().SpaceAvailableForDecompression(data.RootPath, data.File)
if err != nil {
if filesystem.IsErrorCode(err, filesystem.ErrCodeUnknownArchive) {
s.Log().WithField("path", data.RootPath).WithField("file", data.File).WithField("error", err).Warn("failed to decompress file due to unknown format")
lg.WithField("error", err).Warn("failed to decompress file: unknown archive format")
c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"error": "The archive provided is in a format Wings does not understand."})
return
}
@ -402,30 +403,21 @@ func postServerDecompressFiles(c *gin.Context) {
return
}
if !hasSpace {
c.AbortWithStatusJSON(http.StatusConflict, gin.H{
"error": "This server does not have enough available disk space to decompress this archive.",
})
return
}
lg.Info("starting file decompression")
if err := s.Filesystem().DecompressFile(data.RootPath, data.File); err != nil {
// If the file is busy for some reason just return a nicer error to the user since there is not
// much we specifically can do. They'll need to stop the running server process in order to overwrite
// a file like this.
if strings.Contains(err.Error(), "text file busy") {
s.Log().WithField("error", err).Warn("failed to decompress file due to busy text file")
lg.WithField("error", err).Warn("failed to decompress file: text file busy")
c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{
"error": "One or more files this archive is attempting to overwrite are currently in use by another process. Please try again.",
})
return
}
NewServerError(err, s).Abort(c)
middleware.CaptureAndAbort(c, err)
return
}
c.Status(http.StatusNoContent)
}

51
server/filesystem/decompress.go
View File

@ -4,28 +4,29 @@ import (
"archive/tar"
"archive/zip"
"compress/gzip"
"emperror.dev/errors"
"fmt"
"github.com/mholt/archiver/v3"
"os"
"path/filepath"
"reflect"
"strings"
"sync/atomic"
"emperror.dev/errors"
"github.com/mholt/archiver/v3"
)
// Look through a given archive and determine if decompressing it would put the server over
// its allocated disk space limit.
func (fs *Filesystem) SpaceAvailableForDecompression(dir string, file string) (bool, error) {
// SpaceAvailableForDecompression looks through a given archive and determines
// if decompressing it would put the server over its allocated disk space limit.
func (fs *Filesystem) SpaceAvailableForDecompression(dir string, file string) error {
// Don't waste time trying to determine this if we know the server will have the space for
// it since there is no limit.
if fs.MaxDisk() <= 0 {
return true, nil
return nil
}
source, err := fs.SafePath(filepath.Join(dir, file))
if err != nil {
return false, err
return err
}
// Get the cached size in a parallel process so that if it is not cached we are not
@ -38,32 +39,28 @@ func (fs *Filesystem) SpaceAvailableForDecompression(dir string, file string) (b
if atomic.AddInt64(&size, f.Size())+dirSize > fs.MaxDisk() {
return &Error{code: ErrCodeDiskSpace}
}
return nil
})
if err != nil {
if strings.HasPrefix(err.Error(), "format ") {
return false, &Error{code: ErrCodeUnknownArchive}
return &Error{code: ErrCodeUnknownArchive}
}
return false, err
return err
}
return true, err
return err
}
// Decompress a file in a given directory by using the archiver tool to infer the file
// type and go from there. This will walk over all of the files within the given archive
// and ensure that there is not a zip-slip attack being attempted by validating that the
// final path is within the server data directory.
// DecompressFile will decompress a file in a given directory by using the
// archiver tool to infer the file type and go from there. This will walk over
// all of the files within the given archive and ensure that there is not a
// zip-slip attack being attempted by validating that the final path is within
// the server data directory.
func (fs *Filesystem) DecompressFile(dir string, file string) error {
source, err := fs.SafePath(filepath.Join(dir, file))
if err != nil {
return err
}
// Make sure the file exists basically.
// Ensure that the source archive actually exists on the system.
if _, err := os.Stat(source); err != nil {
return err
}
@ -79,7 +76,6 @@ func (fs *Filesystem) DecompressFile(dir string, file string) error {
}
var name string
switch s := f.Sys().(type) {
case *tar.Header:
name = s.Name
@ -88,7 +84,11 @@ func (fs *Filesystem) DecompressFile(dir string, file string) error {
case *zip.FileHeader:
name = s.Name
default:
return errors.New(fmt.Sprintf("could not parse underlying data source with type %s", reflect.TypeOf(s).String()))
return &Error{
code: ErrCodeUnknownError,
resolved: filepath.Join(dir, f.Name()),
err: errors.New(fmt.Sprintf("could not parse underlying data source with type: %s", reflect.TypeOf(s).String())),
}
}
p := filepath.Join(dir, name)
@ -96,15 +96,16 @@ func (fs *Filesystem) DecompressFile(dir string, file string) error {
if err := fs.IsIgnored(p); err != nil {
return nil
}
return errors.WithMessage(fs.Writefile(p, f), "could not extract file from archive")
if err := fs.Writefile(p, f); err != nil {
return &Error{code: ErrCodeUnknownError, err: err, resolved: source}
}
return nil
})
if err != nil {
if strings.HasPrefix(err.Error(), "format ") {
return &Error{code: ErrCodeUnknownArchive}
}
return err
}
return nil
}

95
server/filesystem/errors.go
View File

@ -17,19 +17,33 @@ const (
ErrCodeUnknownArchive ErrorCode = "E_UNKNFMT"
ErrCodePathResolution ErrorCode = "E_BADPATH"
ErrCodeDenylistFile ErrorCode = "E_DENYLIST"
ErrCodeUnknownError ErrorCode = "E_UNKNOWN"
)
type Error struct {
code ErrorCode
path string
code ErrorCode
// Contains the underlying error leading to this. This value may or may not be
// present, it is entirely dependent on how this error was triggered.
err error
// This contains the value of the final destination that triggered this specific
// error event.
resolved string
// This value is generally only present on errors stemming from a path resolution
// error. For everything else you should be setting and reading the resolved path
// value which will be far more useful.
path string
}
// Code returns the ErrorCode for this specific error instance.
func (e *Error) Code() ErrorCode {
return e.code
}
// Returns a human-readable error string to identify the Error by.
func (e *Error) Error() string {
switch e.code {
case ErrCodeIsDirectory:
return "filesystem: is a directory"
return fmt.Sprintf("filesystem: cannot perform action: [%s] is a directory", e.resolved)
case ErrCodeDiskSpace:
return "filesystem: not enough disk space"
case ErrCodeUnknownArchive:
@ -46,36 +60,17 @@ func (e *Error) Error() string {
r = "<empty>"
}
return fmt.Sprintf("filesystem: server path [%s] resolves to a location outside the server root: %s", e.path, r)
case ErrCodeUnknownError:
fallthrough
default:
return fmt.Sprintf("filesystem: an error occurred: %s", e.Cause())
}
return "filesystem: unhandled error type"
}
// Returns the ErrorCode for this specific error instance.
func (e *Error) Code() ErrorCode {
return e.code
}
// Checks if the given error is one of the Filesystem errors.
func IsFilesystemError(err error) (*Error, bool) {
var fserr *Error
if errors.As(err, &fserr) {
return fserr, true
}
return nil, false
}
// Checks if "err" is a filesystem Error type. If so, it will then drop in and check
// that the error code is the same as the provided ErrorCode passed in "code".
func IsErrorCode(err error, code ErrorCode) bool {
if e, ok := IsFilesystemError(err); ok {
return e.code == code
}
return false
}
// Returns a new BadPathResolution error.
func NewBadPathResolution(path string, resolved string) *Error {
return &Error{code: ErrCodePathResolution, path: path, resolved: resolved}
// Cause returns the underlying cause of this filesystem error. In some causes
// there may not be a cause present, in which case nil will be returned.
func (e *Error) Cause() error {
return e.err
}
// Generates an error logger instance with some basic information.
@ -92,10 +87,46 @@ func (fs *Filesystem) handleWalkerError(err error, f os.FileInfo) error {
if !IsErrorCode(err, ErrCodePathResolution) {
return err
}
if f != nil && f.IsDir() {
return filepath.SkipDir
}
return nil
}
// IsFilesystemError checks if the given error is one of the Filesystem errors.
func IsFilesystemError(err error) bool {
var fserr *Error
if err != nil && errors.As(err, &fserr) {
return true
}
return false
}
// IsErrorCode checks if "err" is a filesystem Error type. If so, it will then
// drop in and check that the error code is the same as the provided ErrorCode
// passed in "code".
func IsErrorCode(err error, code ErrorCode) bool {
var fserr *Error
if err != nil && errors.As(err, &fserr) {
return fserr.code == code
}
return false
}
// NewBadPathResolution returns a new BadPathResolution error.
func NewBadPathResolution(path string, resolved string) *Error {
return &Error{code: ErrCodePathResolution, path: path, resolved: resolved}
}
// WrapError wraps the provided error as a Filesystem error and attaches the
// provided resolved source to it. If the error is already a Filesystem error
// no action is taken.
func WrapError(err error, resolved string) *Error {
if err == nil {
return nil
}
if IsFilesystemError(err) {
return err.(*Error)
}
return &Error{code: ErrCodeUnknownError, err: err, resolved: resolved}
}

5
server/filesystem/filesystem.go
View File

@ -123,7 +123,8 @@ func (fs *Filesystem) Readfile(p string, w io.Writer) error {
return err
}
// Writes a file to the system. If the file does not already exist one will be created.
// Writefile writes a file to the system. If the file does not already exist one
// will be created.
func (fs *Filesystem) Writefile(p string, r io.Reader) error {
cleaned, err := fs.SafePath(p)
if err != nil {
@ -138,7 +139,7 @@ func (fs *Filesystem) Writefile(p string, r io.Reader) error {
return err
} else if err == nil {
if stat.IsDir() {
return &Error{code: ErrCodeIsDirectory}
return &Error{code: ErrCodeIsDirectory, resolved: cleaned}
}
currentSize = stat.Size()
}