499 lines
13 KiB
Go
499 lines
13 KiB
Go
package fusefrontend
|
|
|
|
import (
|
|
"context"
|
|
"syscall"
|
|
|
|
"golang.org/x/sys/unix"
|
|
|
|
"github.com/hanwen/go-fuse/v2/fs"
|
|
"github.com/hanwen/go-fuse/v2/fuse"
|
|
|
|
"github.com/rfjakob/gocryptfs/v2/internal/nametransform"
|
|
"github.com/rfjakob/gocryptfs/v2/internal/syscallcompat"
|
|
"github.com/rfjakob/gocryptfs/v2/internal/tlog"
|
|
)
|
|
|
|
// Node is a file or directory in the filesystem tree
|
|
// in a gocryptfs mount.
|
|
type Node struct {
|
|
fs.Inode
|
|
}
|
|
|
|
// Lookup - FUSE call for discovering a file.
|
|
func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
|
|
dirfd, cName, errno := n.prepareAtSyscall(name)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
// Get device number and inode number into `st`
|
|
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
|
|
if err != nil {
|
|
return nil, fs.ToErrno(err)
|
|
}
|
|
|
|
// Create new inode and fill `out`
|
|
ch = n.newChild(ctx, st, out)
|
|
|
|
// Translate ciphertext size in `out.Attr.Size` to plaintext size
|
|
n.translateSize(dirfd, cName, &out.Attr)
|
|
|
|
rn := n.rootNode()
|
|
if rn.args.ForceOwner != nil {
|
|
out.Owner = *rn.args.ForceOwner
|
|
}
|
|
|
|
if rn.args.SharedStorage {
|
|
// If we already have a child node that matches what we found on disk*
|
|
// (as reflected in `ch`), return it here.
|
|
//
|
|
// This keeps the Node ID for each directory entry stable
|
|
// (until forgotten).
|
|
//
|
|
// *We compare `name`, `Ino`, `Mode` (but not `Gen`!)
|
|
old := n.Inode.GetChild(name)
|
|
if old != nil &&
|
|
old.StableAttr().Ino == ch.StableAttr().Ino &&
|
|
// `Mode` has already been masked with syscall.S_IFMT by n.newChild()
|
|
old.StableAttr().Mode == ch.StableAttr().Mode {
|
|
return old, 0
|
|
}
|
|
}
|
|
|
|
return ch, 0
|
|
}
|
|
|
|
// GetAttr - FUSE call for stat()ing a file.
|
|
//
|
|
// GetAttr is symlink-safe through use of openBackingDir() and Fstatat().
|
|
func (n *Node) Getattr(ctx context.Context, f fs.FileHandle, out *fuse.AttrOut) (errno syscall.Errno) {
|
|
// If the kernel gives us a file handle, use it.
|
|
if f != nil {
|
|
return f.(fs.FileGetattrer).Getattr(ctx, out)
|
|
}
|
|
|
|
dirfd, cName, errno := n.prepareAtSyscallMyself()
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
|
|
if err != nil {
|
|
return fs.ToErrno(err)
|
|
}
|
|
|
|
// Fix inode number
|
|
rn := n.rootNode()
|
|
rn.inoMap.TranslateStat(st)
|
|
out.Attr.FromStat(st)
|
|
|
|
// Translate ciphertext size in `out.Attr.Size` to plaintext size
|
|
n.translateSize(dirfd, cName, &out.Attr)
|
|
|
|
if rn.args.ForceOwner != nil {
|
|
out.Owner = *rn.args.ForceOwner
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// Unlink - FUSE call. Delete a file.
|
|
//
|
|
// Symlink-safe through use of Unlinkat().
|
|
func (n *Node) Unlink(ctx context.Context, name string) (errno syscall.Errno) {
|
|
dirfd, cName, errno := n.prepareAtSyscall(name)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
// Delete content
|
|
err := syscallcompat.Unlinkat(dirfd, cName, 0)
|
|
if err != nil {
|
|
return fs.ToErrno(err)
|
|
}
|
|
// Delete ".name" file
|
|
if !n.rootNode().args.PlaintextNames && nametransform.IsLongContent(cName) {
|
|
err = nametransform.DeleteLongNameAt(dirfd, cName)
|
|
if err != nil {
|
|
tlog.Warn.Printf("Unlink: could not delete .name file: %v", err)
|
|
}
|
|
}
|
|
return fs.ToErrno(err)
|
|
}
|
|
|
|
// Readlink - FUSE call.
|
|
//
|
|
// Symlink-safe through openBackingDir() + Readlinkat().
|
|
func (n *Node) Readlink(ctx context.Context) (out []byte, errno syscall.Errno) {
|
|
dirfd, cName, errno := n.prepareAtSyscallMyself()
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
return n.readlink(dirfd, cName)
|
|
}
|
|
|
|
// Setattr - FUSE call. Called for chmod, truncate, utimens, ...
|
|
func (n *Node) Setattr(ctx context.Context, f fs.FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) (errno syscall.Errno) {
|
|
// Use the fd if the kernel gave us one
|
|
if f != nil {
|
|
f2 := f.(*File)
|
|
return f2.Setattr(ctx, in, out)
|
|
}
|
|
|
|
dirfd, cName, errno := n.prepareAtSyscallMyself()
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
// chmod(2)
|
|
//
|
|
// gocryptfs.diriv & gocryptfs.longname.[sha256].name files do NOT get chmod'ed
|
|
// or chown'ed with their parent file/dir for simplicity.
|
|
// See nametransform/perms.go for details.
|
|
if mode, ok := in.GetMode(); ok {
|
|
errno = fs.ToErrno(syscallcompat.FchmodatNofollow(dirfd, cName, mode))
|
|
if errno != 0 {
|
|
return errno
|
|
}
|
|
}
|
|
|
|
// chown(2)
|
|
uid32, uOk := in.GetUID()
|
|
gid32, gOk := in.GetGID()
|
|
if uOk || gOk {
|
|
uid := -1
|
|
gid := -1
|
|
|
|
if uOk {
|
|
uid = int(uid32)
|
|
}
|
|
if gOk {
|
|
gid = int(gid32)
|
|
}
|
|
errno = fs.ToErrno(syscallcompat.Fchownat(dirfd, cName, uid, gid, unix.AT_SYMLINK_NOFOLLOW))
|
|
if errno != 0 {
|
|
return errno
|
|
}
|
|
}
|
|
|
|
// utimens(2)
|
|
mtime, mok := in.GetMTime()
|
|
atime, aok := in.GetATime()
|
|
if mok || aok {
|
|
ap := &atime
|
|
mp := &mtime
|
|
if !aok {
|
|
ap = nil
|
|
}
|
|
if !mok {
|
|
mp = nil
|
|
}
|
|
errno = fs.ToErrno(syscallcompat.UtimesNanoAtNofollow(dirfd, cName, ap, mp))
|
|
if errno != 0 {
|
|
return errno
|
|
}
|
|
}
|
|
|
|
// For truncate, the user has to have write permissions. That means we can
|
|
// depend on opening a RDWR fd and letting the File handle truncate.
|
|
if sz, ok := in.GetSize(); ok {
|
|
f, _, errno := n.Open(ctx, syscall.O_RDWR)
|
|
if errno != 0 {
|
|
return errno
|
|
}
|
|
f2 := f.(*File)
|
|
defer f2.Release(ctx)
|
|
errno = syscall.Errno(f2.truncate(sz))
|
|
if errno != 0 {
|
|
return errno
|
|
}
|
|
return f2.Getattr(ctx, out)
|
|
}
|
|
|
|
return n.Getattr(ctx, nil, out)
|
|
}
|
|
|
|
// StatFs - FUSE call. Returns information about the filesystem.
|
|
//
|
|
// Symlink-safe because the path is ignored.
|
|
func (n *Node) Statfs(ctx context.Context, out *fuse.StatfsOut) syscall.Errno {
|
|
p := n.rootNode().args.Cipherdir
|
|
var st syscall.Statfs_t
|
|
err := syscall.Statfs(p, &st)
|
|
if err != nil {
|
|
return fs.ToErrno(err)
|
|
}
|
|
out.FromStatfsT(&st)
|
|
return 0
|
|
}
|
|
|
|
// Mknod - FUSE call. Create a device file.
|
|
//
|
|
// Symlink-safe through use of Mknodat().
|
|
func (n *Node) Mknod(ctx context.Context, name string, mode, rdev uint32, out *fuse.EntryOut) (inode *fs.Inode, errno syscall.Errno) {
|
|
dirfd, cName, errno := n.prepareAtSyscall(name)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
// Make sure context is nil if we don't want to preserve the owner
|
|
rn := n.rootNode()
|
|
if !rn.args.PreserveOwner {
|
|
ctx = nil
|
|
}
|
|
|
|
// Create ".name" file to store long file name (except in PlaintextNames mode)
|
|
var err error
|
|
ctx2 := toFuseCtx(ctx)
|
|
if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
|
|
err := rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
|
|
if err != nil {
|
|
errno = fs.ToErrno(err)
|
|
return
|
|
}
|
|
// Create "gocryptfs.longfile." device node
|
|
err = syscallcompat.MknodatUser(dirfd, cName, mode, int(rdev), ctx2)
|
|
if err != nil {
|
|
nametransform.DeleteLongNameAt(dirfd, cName)
|
|
}
|
|
} else {
|
|
// Create regular device node
|
|
err = syscallcompat.MknodatUser(dirfd, cName, mode, int(rdev), ctx2)
|
|
}
|
|
if err != nil {
|
|
errno = fs.ToErrno(err)
|
|
return
|
|
}
|
|
|
|
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
|
|
if err != nil {
|
|
errno = fs.ToErrno(err)
|
|
return
|
|
}
|
|
|
|
inode = n.newChild(ctx, st, out)
|
|
|
|
if rn.args.ForceOwner != nil {
|
|
out.Owner = *rn.args.ForceOwner
|
|
}
|
|
|
|
return inode, 0
|
|
}
|
|
|
|
// Link - FUSE call. Creates a hard link at "newPath" pointing to file
|
|
// "oldPath".
|
|
//
|
|
// Symlink-safe through use of Linkat().
|
|
func (n *Node) Link(ctx context.Context, target fs.InodeEmbedder, name string, out *fuse.EntryOut) (inode *fs.Inode, errno syscall.Errno) {
|
|
dirfd, cName, errno := n.prepareAtSyscall(name)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
n2 := toNode(target)
|
|
dirfd2, cName2, errno := n2.prepareAtSyscallMyself()
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd2)
|
|
|
|
// Handle long file name (except in PlaintextNames mode)
|
|
rn := n.rootNode()
|
|
var err error
|
|
if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
|
|
err = rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
|
|
if err != nil {
|
|
errno = fs.ToErrno(err)
|
|
return
|
|
}
|
|
// Create "gocryptfs.longfile." link
|
|
err = unix.Linkat(dirfd2, cName2, dirfd, cName, 0)
|
|
if err != nil {
|
|
nametransform.DeleteLongNameAt(dirfd, cName)
|
|
}
|
|
} else {
|
|
// Create regular link
|
|
err = unix.Linkat(dirfd2, cName2, dirfd, cName, 0)
|
|
}
|
|
if err != nil {
|
|
errno = fs.ToErrno(err)
|
|
return
|
|
}
|
|
|
|
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
|
|
if err != nil {
|
|
errno = fs.ToErrno(err)
|
|
return
|
|
}
|
|
inode = n.newChild(ctx, st, out)
|
|
n.translateSize(dirfd, cName, &out.Attr)
|
|
return inode, 0
|
|
}
|
|
|
|
// Symlink - FUSE call. Create a symlink.
|
|
//
|
|
// Symlink-safe through use of Symlinkat.
|
|
func (n *Node) Symlink(ctx context.Context, target, name string, out *fuse.EntryOut) (inode *fs.Inode, errno syscall.Errno) {
|
|
dirfd, cName, errno := n.prepareAtSyscall(name)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
// Make sure context is nil if we don't want to preserve the owner
|
|
rn := n.rootNode()
|
|
if !rn.args.PreserveOwner {
|
|
ctx = nil
|
|
}
|
|
|
|
cTarget := target
|
|
if !rn.args.PlaintextNames {
|
|
// Symlinks are encrypted like file contents (GCM) and base64-encoded
|
|
cTarget = rn.encryptSymlinkTarget(target)
|
|
}
|
|
// Create ".name" file to store long file name (except in PlaintextNames mode)
|
|
var err error
|
|
ctx2 := toFuseCtx(ctx)
|
|
if !rn.args.PlaintextNames && nametransform.IsLongContent(cName) {
|
|
err = rn.nameTransform.WriteLongNameAt(dirfd, cName, name)
|
|
if err != nil {
|
|
return nil, fs.ToErrno(err)
|
|
}
|
|
// Create "gocryptfs.longfile." symlink
|
|
err = syscallcompat.SymlinkatUser(cTarget, dirfd, cName, ctx2)
|
|
if err != nil {
|
|
nametransform.DeleteLongNameAt(dirfd, cName)
|
|
return nil, fs.ToErrno(err)
|
|
}
|
|
} else {
|
|
// Create symlink
|
|
err = syscallcompat.SymlinkatUser(cTarget, dirfd, cName, ctx2)
|
|
if err != nil {
|
|
return nil, fs.ToErrno(err)
|
|
}
|
|
}
|
|
|
|
st, err := syscallcompat.Fstatat2(dirfd, cName, unix.AT_SYMLINK_NOFOLLOW)
|
|
if err != nil {
|
|
return nil, fs.ToErrno(err)
|
|
}
|
|
// Report the plaintext size, not the encrypted blob size
|
|
st.Size = int64(len(target))
|
|
|
|
inode = n.newChild(ctx, st, out)
|
|
return inode, 0
|
|
}
|
|
|
|
// If we can handle the flags, this function returns 0.
|
|
func rejectRenameFlags(flags uint32) syscall.Errno {
|
|
switch flags {
|
|
case 0, syscallcompat.RENAME_NOREPLACE, syscallcompat.RENAME_EXCHANGE, syscallcompat.RENAME_WHITEOUT:
|
|
return 0
|
|
case syscallcompat.RENAME_NOREPLACE | syscallcompat.RENAME_WHITEOUT:
|
|
return 0
|
|
default:
|
|
tlog.Warn.Printf("rejectRenameFlags: unknown flag combination 0x%x", flags)
|
|
return syscall.EINVAL
|
|
}
|
|
}
|
|
|
|
// Rename - FUSE call.
|
|
// This function is called on the PARENT DIRECTORY of `name`.
|
|
//
|
|
// Symlink-safe through Renameat().
|
|
func (n *Node) Rename(ctx context.Context, name string, newParent fs.InodeEmbedder, newName string, flags uint32) (errno syscall.Errno) {
|
|
if errno = rejectRenameFlags(flags); errno != 0 {
|
|
return errno
|
|
}
|
|
|
|
dirfd, cName, errno := n.prepareAtSyscall(name)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
n2 := toNode(newParent)
|
|
dirfd2, cName2, errno := n2.prepareAtSyscall(newName)
|
|
if errno != 0 {
|
|
return
|
|
}
|
|
defer syscall.Close(dirfd2)
|
|
|
|
// Easy case.
|
|
rn := n.rootNode()
|
|
if rn.args.PlaintextNames {
|
|
return fs.ToErrno(syscallcompat.Renameat2(dirfd, cName, dirfd2, cName2, uint(flags)))
|
|
}
|
|
// Long destination file name: create .name file
|
|
nameFileAlreadyThere := false
|
|
var err error
|
|
if nametransform.IsLongContent(cName2) {
|
|
err = rn.nameTransform.WriteLongNameAt(dirfd2, cName2, newName)
|
|
// Failure to write the .name file is expected when the target path already
|
|
// exists. Since hashes are pretty unique, there is no need to modify the
|
|
// .name file in this case, and we ignore the error.
|
|
if err == syscall.EEXIST {
|
|
nameFileAlreadyThere = true
|
|
} else if err != nil {
|
|
return fs.ToErrno(err)
|
|
}
|
|
}
|
|
// Actual rename
|
|
tlog.Debug.Printf("Renameat %d/%s -> %d/%s\n", dirfd, cName, dirfd2, cName2)
|
|
err = syscallcompat.Renameat2(dirfd, cName, dirfd2, cName2, uint(flags))
|
|
if (flags&syscallcompat.RENAME_NOREPLACE == 0) && (err == syscall.ENOTEMPTY || err == syscall.EEXIST) {
|
|
// If an empty directory is overwritten we will always get an error as
|
|
// the "empty" directory will still contain gocryptfs.diriv.
|
|
// Interestingly, ext4 returns ENOTEMPTY while xfs returns EEXIST.
|
|
// We handle that by trying to fs.Rmdir() the target directory and trying
|
|
// again.
|
|
tlog.Debug.Printf("Rename: Handling ENOTEMPTY")
|
|
if n2.Rmdir(ctx, newName) == 0 {
|
|
err = syscallcompat.Renameat2(dirfd, cName, dirfd2, cName2, uint(flags))
|
|
}
|
|
}
|
|
if err != nil {
|
|
if nametransform.IsLongContent(cName2) && !nameFileAlreadyThere {
|
|
// Roll back .name creation unless the .name file was already there
|
|
nametransform.DeleteLongNameAt(dirfd2, cName2)
|
|
}
|
|
return fs.ToErrno(err)
|
|
}
|
|
if flags&syscallcompat.RENAME_EXCHANGE != 0 || flags&syscallcompat.RENAME_WHITEOUT != 0 {
|
|
// These flags mean that there is now a new file at cName and we
|
|
// should NOT delete its longname file.
|
|
return 0
|
|
}
|
|
if nametransform.IsLongContent(cName) {
|
|
nametransform.DeleteLongNameAt(dirfd, cName)
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// Fsync: handles FUSE opcodes FSYNC & FDIRSYNC
|
|
//
|
|
// Note: f is always set to nil by go-fuse
|
|
func (n *Node) Fsync(ctx context.Context, f fs.FileHandle, flags uint32) syscall.Errno {
|
|
dirfd, cName, errno := n.prepareAtSyscallMyself()
|
|
if errno != 0 {
|
|
return errno
|
|
}
|
|
defer syscall.Close(dirfd)
|
|
|
|
fd, err := syscallcompat.Openat(dirfd, cName, syscall.O_RDONLY|syscall.O_NOFOLLOW, 0)
|
|
if err != nil {
|
|
return fs.ToErrno(err)
|
|
}
|
|
defer syscall.Close(fd)
|
|
|
|
return fs.ToErrno(syscall.Fsync(fd))
|
|
}
|