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authorJakob Unterwurzacher2020-08-02 13:25:53 +0200
committerJakob Unterwurzacher2020-08-02 13:25:53 +0200
commit4674bac8381838718f0defba0f2e0d9eba2a41a3 (patch)
treea33138d2d6c499c19a880cba515d2fc7665e6b28 /internal/fusefrontend_reverse
parent47d8f56b7f9a7dee760deeaeae3e044c0ab65d6a (diff)
v2api/reverse: implement Lookup for gocryptfs.conf & gocryptfs.diriv
Diffstat (limited to 'internal/fusefrontend_reverse')
-rw-r--r--internal/fusefrontend_reverse/node.go59
-rw-r--r--internal/fusefrontend_reverse/virtualfile.go100
2 files changed, 153 insertions, 6 deletions
diff --git a/internal/fusefrontend_reverse/node.go b/internal/fusefrontend_reverse/node.go
index 8af7bed..0b2df12 100644
--- a/internal/fusefrontend_reverse/node.go
+++ b/internal/fusefrontend_reverse/node.go
@@ -9,6 +9,8 @@ import (
"github.com/hanwen/go-fuse/v2/fs"
"github.com/hanwen/go-fuse/v2/fuse"
+ "github.com/rfjakob/gocryptfs/internal/configfile"
+ "github.com/rfjakob/gocryptfs/internal/pathiv"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
)
@@ -19,13 +21,56 @@ type Node struct {
}
// Lookup - FUSE call for discovering a file.
-// TODO handle virtual files
func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
- dirfd, pName, errno := n.prepareAtSyscall(name)
- if errno != 0 {
+ dirfd := int(-1)
+ pName := ""
+ t := n.lookupFileType(name)
+ // gocryptfs.conf
+ if t == typeConfig {
+ var err error
+ rn := n.rootNode()
+ dirfd, err = syscallcompat.OpenDirNofollow(rn.args.Cipherdir, "")
+ if err != nil {
+ errno = fs.ToErrno(err)
+ return
+ }
+ defer syscall.Close(dirfd)
+ pName = configfile.ConfReverseName
+ } else if t == typeDiriv {
+ // gocryptfs.diriv
+ dirfd, pName, errno = n.prepareAtSyscall("")
+ if errno != 0 {
+ return
+ }
+ defer syscall.Close(dirfd)
+ st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
+ if err != nil {
+ errno = fs.ToErrno(err)
+ return
+ }
+ content := pathiv.Derive(n.Path(), pathiv.PurposeDirIV)
+ var vf *virtualFile
+ vf, errno = n.newVirtualFile(content, st, inoTagDirIV)
+ if errno != 0 {
+ return nil, errno
+ }
+ out.Attr = vf.attr
+ // Create child node
+ id := fs.StableAttr{Mode: uint32(vf.attr.Mode), Gen: 1, Ino: vf.attr.Ino}
+ ch = n.NewInode(ctx, vf, id)
return
+ } else if t == typeName {
+ // gocryptfs.longname.*.name
+
+ // TODO
+ } else if t == typeReal {
+ // real file
+ dirfd, pName, errno = n.prepareAtSyscall(name)
+ if errno != 0 {
+ return
+ }
+ defer syscall.Close(dirfd)
}
- defer syscall.Close(dirfd)
// Get device number and inode number into `st`
st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
@@ -36,8 +81,10 @@ func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (ch
// 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, pName, &out.Attr)
+ if t == typeReal {
+ // Translate ciphertext size in `out.Attr.Size` to plaintext size
+ n.translateSize(dirfd, pName, &out.Attr)
+ }
return ch, 0
}
diff --git a/internal/fusefrontend_reverse/virtualfile.go b/internal/fusefrontend_reverse/virtualfile.go
index a92c127..a7f6913 100644
--- a/internal/fusefrontend_reverse/virtualfile.go
+++ b/internal/fusefrontend_reverse/virtualfile.go
@@ -1,7 +1,16 @@
package fusefrontend_reverse
import (
+ "context"
+ "log"
"syscall"
+
+ "github.com/hanwen/go-fuse/v2/fs"
+ "github.com/hanwen/go-fuse/v2/fuse"
+
+ "github.com/rfjakob/gocryptfs/internal/configfile"
+ "github.com/rfjakob/gocryptfs/internal/inomap"
+ "github.com/rfjakob/gocryptfs/internal/nametransform"
)
const (
@@ -13,3 +22,94 @@ const (
inoTagDirIV = 1
inoTagNameFile = 2
)
+
+type fileType int
+
+// Values returned by lookupFileType
+const (
+ // A real file/directory/symlink in the backing plaintext directory
+ typeReal fileType = iota
+ // A DirIV (gocryptfs.diriv) file
+ typeDiriv
+ // A gocryptfs.longname.*.name file for a file with a long name
+ typeName
+ // The config file gocryptfs.conf
+ typeConfig
+)
+
+// lookupFileType returns the type of child file name
+// (one of the fileType constants above). Called from Lookup().
+func (n *Node) lookupFileType(cName string) fileType {
+ rn := n.rootNode()
+ // In -plaintextname mode, neither diriv nor longname files exist.
+ if !rn.args.PlaintextNames {
+ // Is it a gocryptfs.diriv file?
+ if cName == nametransform.DirIVFilename {
+ return typeDiriv
+ }
+ // Is it a gocryptfs.longname.*.name file?
+ if t := nametransform.NameType(cName); t == nametransform.LongNameFilename {
+ return typeName
+ }
+ }
+ // gocryptfs.conf in the root directory. This is passed through to
+ // .gocryptfs.reverse.conf in the backing plaintext directory.
+ if n.isRoot() && !rn.args.ConfigCustom && cName == configfile.ConfDefaultName {
+ return typeConfig
+ }
+ return typeReal
+}
+
+type virtualFile struct {
+ fs.Inode
+
+ // file content
+ content []byte
+ // attributes for Getattr()
+ attr fuse.Attr
+}
+
+// newVirtualFile creates a new in-memory file that does not have a representation
+// on disk. "content" is the file content. Timestamps and file owner are copied
+// from "parentFile" (file descriptor).
+// For a "gocryptfs.diriv" file, you would use the parent directory as
+// "parentFile".
+func (n *Node) newVirtualFile(content []byte, parentStat *syscall.Stat_t, inoTag uint8) (vf *virtualFile, errno syscall.Errno) {
+ if inoTag == 0 {
+ log.Panicf("BUG: inoTag for virtual file is zero - this will cause ino collisions!")
+ }
+
+ // Adjust inode number and size
+ rn := n.rootNode()
+ st := parentStat
+ q := inomap.NewQIno(uint64(st.Dev), inoTag, uint64(st.Ino))
+ st.Ino = rn.inoMap.Translate(q)
+ st.Size = int64(len(content))
+ st.Mode = virtualFileMode
+ st.Nlink = 1
+ var a fuse.Attr
+ a.FromStat(st)
+
+ vf = &virtualFile{content: content, attr: a}
+ return
+}
+
+// Open - FUSE call
+func (f *virtualFile) Open(ctx context.Context, flags uint32) (fh fs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
+ return nil, fuse.FOPEN_KEEP_CACHE, 0
+}
+
+// GetAttr - FUSE call
+func (f *virtualFile) Getattr(ctx context.Context, fh fs.FileHandle, out *fuse.AttrOut) syscall.Errno {
+ out.Attr = f.attr
+ return 0
+}
+
+// Read - FUSE call
+func (f *virtualFile) Read(ctx context.Context, fh fs.FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
+ end := int(off) + len(dest)
+ if end > len(f.content) {
+ end = len(f.content)
+ }
+ return fuse.ReadResultData(f.content[off:end]), 0
+}