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authorJakob Unterwurzacher2018-11-04 22:25:32 +0100
committerJakob Unterwurzacher2019-01-01 16:24:25 +0100
commit436f918c21a0858c769e1bf7d86502a05132b4e7 (patch)
tree3ba09841716df16e0ff83a984ab7bc86de710a12 /internal/fusefrontend
parent2de3851abddd26949b72b9b255ce836fc93ed284 (diff)
fusefrontend: make Rmdir symlink-safe
Now uses Unlinkat.
Diffstat (limited to 'internal/fusefrontend')
-rw-r--r--internal/fusefrontend/fs.go2
-rw-r--r--internal/fusefrontend/fs_dir.go49
2 files changed, 22 insertions, 29 deletions
diff --git a/internal/fusefrontend/fs.go b/internal/fusefrontend/fs.go
index 2108ea4..444a34a 100644
--- a/internal/fusefrontend/fs.go
+++ b/internal/fusefrontend/fs.go
@@ -502,6 +502,8 @@ func (fs *FS) Symlink(target string, linkName string, context *fuse.Context) (co
}
// Rename - FUSE call.
+//
+// Symlink-safe through Renameat().
func (fs *FS) Rename(oldPath string, newPath string, context *fuse.Context) (code fuse.Status) {
if fs.isFiltered(newPath) {
return fuse.EPERM
diff --git a/internal/fusefrontend/fs_dir.go b/internal/fusefrontend/fs_dir.go
index 5a6bc9d..d4117fb 100644
--- a/internal/fusefrontend/fs_dir.go
+++ b/internal/fusefrontend/fs_dir.go
@@ -5,7 +5,6 @@ package fusefrontend
import (
"fmt"
"io"
- "os"
"path/filepath"
"runtime"
"syscall"
@@ -134,52 +133,44 @@ func haveDsstore(entries []fuse.DirEntry) bool {
return false
}
-// Rmdir implements pathfs.FileSystem
-func (fs *FS) Rmdir(path string, context *fuse.Context) (code fuse.Status) {
- cPath, err := fs.getBackingPath(path)
+// Rmdir - FUSE call.
+//
+// Symlink-safe through Unlinkat() + AT_REMOVEDIR.
+func (fs *FS) Rmdir(relPath string, context *fuse.Context) (code fuse.Status) {
+ parentDirFd, cName, err := fs.openBackingDir(relPath)
if err != nil {
return fuse.ToStatus(err)
}
+ defer syscall.Close(parentDirFd)
if fs.args.PlaintextNames {
- err = syscall.Rmdir(cPath)
- return fuse.ToStatus(err)
- }
- parentDir := filepath.Dir(cPath)
- parentDirFd, err := syscall.Open(parentDir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
- if err != nil {
+ // Unlinkat with AT_REMOVEDIR is equivalent to Rmdir
+ err = unix.Unlinkat(parentDirFd, cName, unix.AT_REMOVEDIR)
return fuse.ToStatus(err)
}
- defer syscall.Close(parentDirFd)
-
- cName := filepath.Base(cPath)
dirfd, err := syscallcompat.Openat(parentDirFd, cName,
syscall.O_RDONLY|syscall.O_NOFOLLOW, 0)
if err == syscall.EACCES {
// We need permission to read and modify the directory
tlog.Debug.Printf("Rmdir: handling EACCESS")
- // TODO use syscall.Fstatat once it is available in Go
- var fi os.FileInfo
- fi, err = os.Lstat(cPath)
+ var st unix.Stat_t
+ err = syscallcompat.Fstatat(parentDirFd, cName, &st, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
tlog.Debug.Printf("Rmdir: Stat: %v", err)
return fuse.ToStatus(err)
}
- origMode := fi.Mode()
- // TODO use syscall.Chmodat once it is available in Go
- err = os.Chmod(cPath, origMode|0700)
+ origMode := st.Mode & 0777
+ err = syscallcompat.Fchmodat(parentDirFd, cName, origMode|0700, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
- tlog.Debug.Printf("Rmdir: Chmod failed: %v", err)
+ tlog.Debug.Printf("Rmdir: Fchmodat failed: %v", err)
return fuse.ToStatus(err)
}
// Retry open
- var st syscall.Stat_t
- syscall.Lstat(cPath, &st)
dirfd, err = syscallcompat.Openat(parentDirFd, cName,
syscall.O_RDONLY|syscall.O_NOFOLLOW, 0)
// Undo the chmod if removing the directory failed
defer func() {
if code != fuse.OK {
- err = os.Chmod(cPath, origMode)
+ err = syscallcompat.Fchmodat(parentDirFd, cName, origMode, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
tlog.Warn.Printf("Rmdir: Chmod rollback failed: %v", err)
}
@@ -196,8 +187,9 @@ retry:
children, err := syscallcompat.Getdents(dirfd)
if err == io.EOF {
// The directory is empty
- tlog.Warn.Printf("Rmdir: %q: gocryptfs.diriv is missing", cPath)
- return fuse.ToStatus(syscall.Rmdir(cPath))
+ tlog.Warn.Printf("Rmdir: %q: gocryptfs.diriv is missing", cName)
+ err = unix.Unlinkat(parentDirFd, cName, unix.AT_REMOVEDIR)
+ return fuse.ToStatus(err)
}
if err != nil {
tlog.Warn.Printf("Rmdir: Readdirnames: %v", err)
@@ -206,13 +198,12 @@ retry:
// MacOS sprinkles .DS_Store files everywhere. This is hard to avoid for
// users, so handle it transparently here.
if runtime.GOOS == "darwin" && len(children) <= 2 && haveDsstore(children) {
- ds := filepath.Join(cPath, dsStoreName)
- err = syscall.Unlink(ds)
+ err = unix.Unlinkat(dirfd, dsStoreName, 0)
if err != nil {
- tlog.Warn.Printf("Rmdir: failed to delete blocking file %q: %v", ds, err)
+ tlog.Warn.Printf("Rmdir: failed to delete blocking file %q: %v", dsStoreName, err)
return fuse.ToStatus(err)
}
- tlog.Warn.Printf("Rmdir: had to delete blocking file %q", ds)
+ tlog.Warn.Printf("Rmdir: had to delete blocking file %q", dsStoreName)
goto retry
}
// If the directory is not empty besides gocryptfs.diriv, do not even