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authorJakob Unterwurzacher2020-05-03 15:22:10 +0200
committerJakob Unterwurzacher2020-05-03 15:22:10 +0200
commit518771e4e247762f60c5594de427a8c86f19bd57 (patch)
tree625aed59393508f8f3b61787963012a684b37d8e /internal
parentdb93a6c54cfd615561207f1bbcf7e665ebc296b6 (diff)
fusefrontend_reverse: use inomap for inode number translation
Gets rid of static inode number value limitations. Fixes https://github.com/rfjakob/gocryptfs/issues/457
Diffstat (limited to 'internal')
-rw-r--r--internal/fusefrontend_reverse/reverse_longnames.go2
-rw-r--r--internal/fusefrontend_reverse/rfs.go31
-rw-r--r--internal/fusefrontend_reverse/virtualfile.go52
-rw-r--r--internal/inomap/inomap.go16
-rw-r--r--internal/inomap/inomap_test.go2
-rw-r--r--internal/inomap/qino.go26
6 files changed, 71 insertions, 58 deletions
diff --git a/internal/fusefrontend_reverse/reverse_longnames.go b/internal/fusefrontend_reverse/reverse_longnames.go
index f07e413..199356b 100644
--- a/internal/fusefrontend_reverse/reverse_longnames.go
+++ b/internal/fusefrontend_reverse/reverse_longnames.go
@@ -122,5 +122,5 @@ func (rfs *ReverseFS) newNameFile(relPath string) (nodefs.File, fuse.Status) {
}
content := []byte(rfs.nameTransform.EncryptName(pName, dirIV))
parentFile := filepath.Join(pDir, pName)
- return rfs.newVirtualFile(content, rfs.args.Cipherdir, parentFile, inoBaseNameFile)
+ return rfs.newVirtualFile(content, rfs.args.Cipherdir, parentFile, inoTagNameFile)
}
diff --git a/internal/fusefrontend_reverse/rfs.go b/internal/fusefrontend_reverse/rfs.go
index 49ce0a1..6bbdfb5 100644
--- a/internal/fusefrontend_reverse/rfs.go
+++ b/internal/fusefrontend_reverse/rfs.go
@@ -15,6 +15,7 @@ import (
"github.com/rfjakob/gocryptfs/internal/contentenc"
"github.com/rfjakob/gocryptfs/internal/cryptocore"
"github.com/rfjakob/gocryptfs/internal/fusefrontend"
+ "github.com/rfjakob/gocryptfs/internal/inomap"
"github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/pathiv"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
@@ -38,6 +39,9 @@ type ReverseFS struct {
contentEnc *contentenc.ContentEnc
// Tests wheter a path is excluded (hiden) from the user. Used by -exclude.
excluder ignore.IgnoreParser
+ // inoMap translates inode numbers from different devices to unique inode
+ // numbers.
+ inoMap *inomap.InoMap
}
var _ pathfs.FileSystem = &ReverseFS{}
@@ -54,6 +58,7 @@ func NewFS(args fusefrontend.Args, c *contentenc.ContentEnc, n nametransform.Nam
args: args,
nameTransform: n,
contentEnc: c,
+ inoMap: inomap.New(),
}
fs.prepareExcluder(args)
return fs
@@ -180,6 +185,7 @@ func (rfs *ReverseFS) GetAttr(relPath string, context *fuse.Context) (*fuse.Attr
if err != nil {
return nil, fuse.ToStatus(err)
}
+ rfs.inoMap.TranslateStat(&st)
var a fuse.Attr
a.FromStat(&st)
if rfs.args.ForceOwner != nil {
@@ -211,26 +217,25 @@ func (rfs *ReverseFS) GetAttr(relPath string, context *fuse.Context) (*fuse.Attr
}
return &a, status
}
+ // Normal file / directory
dirfd, name, err := rfs.openBackingDir(pPath)
if err != nil {
return nil, fuse.ToStatus(err)
}
// Stat the backing file/dir using Fstatat
- var st unix.Stat_t
- err = syscallcompat.Fstatat(dirfd, name, &st, unix.AT_SYMLINK_NOFOLLOW)
- syscall.Close(dirfd)
- if err != nil {
- return nil, fuse.ToStatus(err)
- }
- // Instead of risking an inode number collision, we return an error.
- if st.Ino > inoBaseMin {
- tlog.Warn.Printf("GetAttr %q: backing file inode number %d crosses reserved space, max=%d. Returning EOVERFLOW.",
- relPath, st.Ino, inoBaseMin)
- return nil, fuse.ToStatus(syscall.EOVERFLOW)
+ var st syscall.Stat_t
+ {
+ var st2 unix.Stat_t
+ err = syscallcompat.Fstatat(dirfd, name, &st2, unix.AT_SYMLINK_NOFOLLOW)
+ syscall.Close(dirfd)
+ if err != nil {
+ return nil, fuse.ToStatus(err)
+ }
+ st = syscallcompat.Unix2syscall(st2)
}
+ rfs.inoMap.TranslateStat(&st)
var a fuse.Attr
- st2 := syscallcompat.Unix2syscall(st)
- a.FromStat(&st2)
+ a.FromStat(&st)
// Calculate encrypted file size
if a.IsRegular() {
a.Size = rfs.contentEnc.PlainSizeToCipherSize(a.Size)
diff --git a/internal/fusefrontend_reverse/virtualfile.go b/internal/fusefrontend_reverse/virtualfile.go
index 963c801..7d1c18c 100644
--- a/internal/fusefrontend_reverse/virtualfile.go
+++ b/internal/fusefrontend_reverse/virtualfile.go
@@ -10,6 +10,7 @@ import (
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
+ "github.com/rfjakob/gocryptfs/internal/inomap"
"github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/pathiv"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
@@ -20,19 +21,10 @@ const (
// virtualFileMode is the mode to use for virtual files (gocryptfs.diriv and
// *.name). They are always readable, as stated in func Access
virtualFileMode = syscall.S_IFREG | 0444
- // inoBaseDirIV is the start of the inode number range that is used
- // for virtual gocryptfs.diriv files. inoBaseNameFile is the thing for
- // *.name files.
- // The value 10^19 is just below 2^60. A power of 10 has been chosen so the
- // "ls -li" output (which is base-10) is easy to read.
- // 10^19 is the largest power of 10 that is smaller than
- // INT64_MAX (=UINT64_MAX/2). This avoids signedness issues.
- inoBaseDirIV = uint64(1000000000000000000)
- inoBaseNameFile = uint64(2000000000000000000)
- // inoBaseMin marks the start of the inode number space that is
- // reserved for virtual files. It is the lowest of the inoBaseXXX values
- // above.
- inoBaseMin = inoBaseDirIV
+ // We use inomap's `Tag` feature to generate unique inode numbers for
+ // virtual files. These are the tags we use.
+ inoTagDirIV = 1
+ inoTagNameFile = 2
)
func (rfs *ReverseFS) newDirIVFile(cRelPath string) (nodefs.File, fuse.Status) {
@@ -42,20 +34,23 @@ func (rfs *ReverseFS) newDirIVFile(cRelPath string) (nodefs.File, fuse.Status) {
return nil, fuse.ToStatus(err)
}
iv := pathiv.Derive(cDir, pathiv.PurposeDirIV)
- return rfs.newVirtualFile(iv, rfs.args.Cipherdir, dir, inoBaseDirIV)
+ return rfs.newVirtualFile(iv, rfs.args.Cipherdir, dir, inoTagDirIV)
}
type virtualFile struct {
// Embed nodefs.defaultFile for a ENOSYS implementation of all methods
nodefs.File
+ // pointer to parent filesystem
+ rfs *ReverseFS
// file content
content []byte
// backing directory
cipherdir string
// path to a parent file (relative to cipherdir)
parentFile string
- // inode number of a virtual file is inode of parent file plus inoBase
- inoBase uint64
+ // inomap `Tag`.
+ // Depending on the file type, either `inoTagDirIV` or `inoTagNameFile`.
+ inoTag uint8
}
// newVirtualFile creates a new in-memory file that does not have a representation
@@ -63,16 +58,17 @@ type virtualFile struct {
// from "parentFile" (plaintext path relative to "cipherdir").
// For a "gocryptfs.diriv" file, you would use the parent directory as
// "parentFile".
-func (rfs *ReverseFS) newVirtualFile(content []byte, cipherdir string, parentFile string, inoBase uint64) (nodefs.File, fuse.Status) {
- if inoBase < inoBaseMin {
- log.Panicf("BUG: virtual inode number base %d is below reserved space", inoBase)
+func (rfs *ReverseFS) newVirtualFile(content []byte, cipherdir string, parentFile string, inoTag uint8) (nodefs.File, fuse.Status) {
+ if inoTag == 0 {
+ log.Panicf("BUG: inoTag for virtual file is zero - this will cause ino collisions!")
}
return &virtualFile{
File: nodefs.NewDefaultFile(),
+ rfs: rfs,
content: content,
cipherdir: cipherdir,
parentFile: parentFile,
- inoBase: inoBase,
+ inoTag: inoTag,
}, fuse.OK
}
@@ -97,22 +93,18 @@ func (f *virtualFile) GetAttr(a *fuse.Attr) fuse.Status {
}
defer syscall.Close(dirfd)
name := filepath.Base(f.parentFile)
- var st unix.Stat_t
- err = syscallcompat.Fstatat(dirfd, name, &st, unix.AT_SYMLINK_NOFOLLOW)
+ var st2 unix.Stat_t
+ err = syscallcompat.Fstatat(dirfd, name, &st2, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
tlog.Debug.Printf("GetAttr: Fstatat %q: %v\n", f.parentFile, err)
return fuse.ToStatus(err)
}
- if st.Ino > inoBaseMin {
- tlog.Warn.Printf("virtualFile.GetAttr: parent file inode number %d crosses reserved space, max=%d. Returning EOVERFLOW.",
- st.Ino, inoBaseMin)
- return fuse.ToStatus(syscall.EOVERFLOW)
- }
- st.Ino = st.Ino + f.inoBase
+ st := syscallcompat.Unix2syscall(st2)
+ q := inomap.NewQIno(uint64(st.Dev), f.inoTag, uint64(st.Ino))
+ st.Ino = f.rfs.inoMap.Translate(q)
st.Size = int64(len(f.content))
st.Mode = virtualFileMode
st.Nlink = 1
- st2 := syscallcompat.Unix2syscall(st)
- a.FromStat(&st2)
+ a.FromStat(&st)
return fuse.OK
}
diff --git a/internal/inomap/inomap.go b/internal/inomap/inomap.go
index c277849..0ca43e4 100644
--- a/internal/inomap/inomap.go
+++ b/internal/inomap/inomap.go
@@ -15,6 +15,7 @@
package inomap
import (
+ "fmt"
"log"
"sync"
"syscall"
@@ -72,23 +73,30 @@ func (m *InoMap) spill(in QIno) (out uint64) {
func (m *InoMap) Translate(in QIno) (out uint64) {
m.Lock()
defer m.Unlock()
+ defer func() {
+ fmt.Printf("Translate: %v -> %d\n", in, out)
+ }()
if in.Ino > maxPassthruIno {
- return m.spill(in)
+ out = m.spill(in)
+ return out
}
ns, found := m.namespaceMap[in.namespaceData]
// Use existing namespace
if found {
- return uint64(ns)<<48 | in.Ino
+ out = uint64(ns)<<48 | in.Ino
+ return out
}
// No free namespace slots?
if m.namespaceNext >= maxNamespaceId {
- return m.spill(in)
+ out = m.spill(in)
+ return out
}
ns = m.namespaceNext
m.namespaceNext++
m.namespaceMap[in.namespaceData] = ns
- return uint64(ns)<<48 | in.Ino
+ out = uint64(ns)<<48 | in.Ino
+ return out
}
// TranslateStat translates the inode number contained in "st" if neccessary.
diff --git a/internal/inomap/inomap_test.go b/internal/inomap/inomap_test.go
index 8efc960..78cb405 100644
--- a/internal/inomap/inomap_test.go
+++ b/internal/inomap/inomap_test.go
@@ -106,7 +106,7 @@ func TestUniqueness(t *testing.T) {
var q QIno
outMap := make(map[uint64]struct{})
for q.Dev = 0; q.Dev < 10; q.Dev++ {
- for q.Flags = 0; q.Flags < 10; q.Flags++ {
+ for q.Tag = 0; q.Tag < 10; q.Tag++ {
// some go into spill
for q.Ino = maxPassthruIno - 100; q.Ino < maxPassthruIno+100; q.Ino++ {
out := m.Translate(q)
diff --git a/internal/inomap/qino.go b/internal/inomap/qino.go
index a74a96d..ed514e8 100644
--- a/internal/inomap/qino.go
+++ b/internal/inomap/qino.go
@@ -7,9 +7,11 @@ import (
type namespaceData struct {
// Stat_t.Dev is uint64 on 32- and 64-bit Linux
Dev uint64
- // Flags acts like an extension of the Dev field.
+ // Tag acts like an extension of the Dev field.
// It is used by reverse mode for virtual files.
- Flags uint8
+ // Normal (forward) mode does not use it and it
+ // stays always zero there.
+ Tag uint8
}
// QIno = Qualified Inode number.
@@ -21,15 +23,21 @@ type QIno struct {
Ino uint64
}
-// QInoFromStat fills a new QIno struct with the passed Stat_t info.
-func QInoFromStat(st *syscall.Stat_t) QIno {
+// NewQIno returns a filled QIno struct
+func NewQIno(dev uint64, tag uint8, ino uint64) QIno {
return QIno{
namespaceData: namespaceData{
- // There are some architectures that use 32-bit values here
- // (darwin, freebsd-32, maybe others). Add an explicit cast to make
- // this function work everywhere.
- Dev: uint64(st.Dev),
+ Dev: dev,
+ Tag: tag,
},
- Ino: uint64(st.Ino),
+ Ino: ino,
}
}
+
+// QInoFromStat fills a new QIno struct with the passed Stat_t info.
+func QInoFromStat(st *syscall.Stat_t) QIno {
+ // There are some architectures that use 32-bit values here
+ // (darwin, freebsd-32, maybe others). Add an explicit cast to make
+ // this function work everywhere.
+ return NewQIno(uint64(st.Dev), 0, uint64(st.Ino))
+}