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authorSebastian Lackner2017-11-29 13:21:28 +0100
committerSebastian Lackner2017-11-29 13:28:04 +0100
commit614745ee576760023961fbf815985b90f90ad1d7 (patch)
treed2577781a64df82303ed569c95cfb9a658fae5f6 /internal/fusefrontend/fs_dir.go
parent67bcbe81e80da29fb340c5a4712831f70442d8c9 (diff)
fusefrontend: allow_other: close race between mkdir and chown
Fixes the same problem as described in 72b975867a3b9bdf53fc2da62e2ba4a328d7e4ab, except for directories instead of device nodes.
Diffstat (limited to 'internal/fusefrontend/fs_dir.go')
-rw-r--r--internal/fusefrontend/fs_dir.go44
1 files changed, 20 insertions, 24 deletions
diff --git a/internal/fusefrontend/fs_dir.go b/internal/fusefrontend/fs_dir.go
index ae150b5..4ffaaff 100644
--- a/internal/fusefrontend/fs_dir.go
+++ b/internal/fusefrontend/fs_dir.go
@@ -24,7 +24,7 @@ import (
const dsStoreName = ".DS_Store"
-func (fs *FS) mkdirWithIv(cPath string, mode uint32) error {
+func (fs *FS) mkdirWithIv(dirfd *os.File, cName string, mode uint32) error {
// Between the creation of the directory and the creation of gocryptfs.diriv
// the directory is inconsistent. Take the lock to prevent other readers
// from seeing it.
@@ -32,14 +32,14 @@ func (fs *FS) mkdirWithIv(cPath string, mode uint32) error {
// The new directory may take the place of an older one that is still in the cache
fs.nameTransform.DirIVCache.Clear()
defer fs.dirIVLock.Unlock()
- err := os.Mkdir(cPath, os.FileMode(mode))
+ err := syscallcompat.Mkdirat(int(dirfd.Fd()), cName, mode)
if err != nil {
return err
}
// Create gocryptfs.diriv
- err = nametransform.WriteDirIV(cPath)
+ err = nametransform.WriteDirIV(dirfd, cName)
if err != nil {
- err2 := syscall.Rmdir(cPath)
+ err2 := syscallcompat.Unlinkat(int(dirfd.Fd()), cName, unix.AT_REMOVEDIR)
if err2 != nil {
tlog.Warn.Printf("mkdirWithIv: rollback failed: %v", err2)
}
@@ -52,17 +52,19 @@ func (fs *FS) Mkdir(newPath string, mode uint32, context *fuse.Context) (code fu
if fs.isFiltered(newPath) {
return fuse.EPERM
}
- cPath, err := fs.getBackingPath(newPath)
+ dirfd, cName, err := fs.openBackingPath(newPath)
if err != nil {
return fuse.ToStatus(err)
}
+ defer dirfd.Close()
if fs.args.PlaintextNames {
- err = os.Mkdir(cPath, os.FileMode(mode))
+ err = syscallcompat.Mkdirat(int(dirfd.Fd()), cName, mode)
// Set owner
if fs.args.PreserveOwner {
- err = os.Lchown(cPath, int(context.Owner.Uid), int(context.Owner.Gid))
+ err = syscallcompat.Fchownat(int(dirfd.Fd()), cName, int(context.Owner.Uid),
+ int(context.Owner.Gid), unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
- tlog.Warn.Printf("Mkdir: Lchown failed: %v", err)
+ tlog.Warn.Printf("Mkdir: Fchownat failed: %v", err)
}
}
return fuse.ToStatus(err)
@@ -73,15 +75,7 @@ func (fs *FS) Mkdir(newPath string, mode uint32, context *fuse.Context) (code fu
mode = mode | 0300
// Handle long file name
- cName := filepath.Base(cPath)
if nametransform.IsLongContent(cName) {
- var dirfd *os.File
- dirfd, err = os.Open(filepath.Dir(cPath))
- if err != nil {
- return fuse.ToStatus(err)
- }
- defer dirfd.Close()
-
// Create ".name"
err = fs.nameTransform.WriteLongName(dirfd, cName, newPath)
if err != nil {
@@ -89,33 +83,35 @@ func (fs *FS) Mkdir(newPath string, mode uint32, context *fuse.Context) (code fu
}
// Create directory
- err = fs.mkdirWithIv(cPath, mode)
+ err = fs.mkdirWithIv(dirfd, cName, mode)
if err != nil {
nametransform.DeleteLongName(dirfd, cName)
return fuse.ToStatus(err)
}
} else {
- err = fs.mkdirWithIv(cPath, mode)
+ err = fs.mkdirWithIv(dirfd, cName, mode)
if err != nil {
return fuse.ToStatus(err)
}
}
// Set permissions back to what the user wanted
if origMode != mode {
- err = os.Chmod(cPath, os.FileMode(origMode))
+ err = syscallcompat.Fchmodat(int(dirfd.Fd()), cName, origMode, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
- tlog.Warn.Printf("Mkdir: Chmod failed: %v", err)
+ tlog.Warn.Printf("Mkdir: Fchmodat failed: %v", err)
}
}
// Set owner
if fs.args.PreserveOwner {
- err = os.Lchown(cPath, int(context.Owner.Uid), int(context.Owner.Gid))
+ err = syscallcompat.Fchownat(int(dirfd.Fd()), cName, int(context.Owner.Uid),
+ int(context.Owner.Gid), unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
- tlog.Warn.Printf("Mkdir: Lchown 1 failed: %v", err)
+ tlog.Warn.Printf("Mkdir: Fchownat 1 failed: %v", err)
}
- err = os.Lchown(filepath.Join(cPath, nametransform.DirIVFilename), int(context.Owner.Uid), int(context.Owner.Gid))
+ err = syscallcompat.Fchownat(int(dirfd.Fd()), filepath.Join(cName, nametransform.DirIVFilename),
+ int(context.Owner.Uid), int(context.Owner.Gid), unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
- tlog.Warn.Printf("Mkdir: Lchown 2 failed: %v", err)
+ tlog.Warn.Printf("Mkdir: Fchownat 2 failed: %v", err)
}
}
return fuse.OK