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v2api: merge openBackingDir into root_node.go

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This commit is contained in:
Jakob Unterwurzacher 2020-07-04 21:42:04 +02:00
parent d2139e18ef
commit 1f4e554168
2 changed files with 60 additions and 68 deletions
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68
internal/fusefrontend/node_openbackingdir.go
View File

@ -1,68 +0,0 @@
package fusefrontend
import (
"path/filepath"
"strings"
"syscall"
"github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
)
// openBackingDir opens the parent ciphertext directory of plaintext path
// "relPath". It returns the dirfd (opened with O_PATH) and the encrypted
// basename.
//
// The caller should then use Openat(dirfd, cName, ...) and friends.
// For convenience, if relPath is "", cName is going to be ".".
//
// openBackingDir is secure against symlink races by using Openat and
// ReadDirIVAt.
func (rn *RootNode) openBackingDir(relPath string) (dirfd int, cName string, err error) {
dirRelPath := nametransform.Dir(relPath)
// With PlaintextNames, we don't need to read DirIVs. Easy.
if rn.args.PlaintextNames {
dirfd, err = syscallcompat.OpenDirNofollow(rn.args.Cipherdir, dirRelPath)
if err != nil {
return -1, "", err
}
// If relPath is empty, cName is ".".
cName = filepath.Base(relPath)
return dirfd, cName, nil
}
// Open cipherdir (following symlinks)
dirfd, err = syscall.Open(rn.args.Cipherdir, syscall.O_DIRECTORY|syscallcompat.O_PATH, 0)
if err != nil {
return -1, "", err
}
// If relPath is empty, cName is ".".
if relPath == "" {
return dirfd, ".", nil
}
// Walk the directory tree
parts := strings.Split(relPath, "/")
for i, name := range parts {
iv, err := nametransform.ReadDirIVAt(dirfd)
if err != nil {
syscall.Close(dirfd)
return -1, "", err
}
cName, err = rn.nameTransform.EncryptAndHashName(name, iv)
if err != nil {
syscall.Close(dirfd)
return -1, "", err
}
// Last part? We are done.
if i == len(parts)-1 {
break
}
// Not the last part? Descend into next directory.
dirfd2, err := syscallcompat.Openat(dirfd, cName, syscall.O_NOFOLLOW|syscall.O_DIRECTORY|syscallcompat.O_PATH, 0)
syscall.Close(dirfd)
if err != nil {
return -1, "", err
}
dirfd = dirfd2
}
return dirfd, cName, nil
}

60
internal/fusefrontend/root_node.go
View File

@ -2,6 +2,8 @@ package fusefrontend
import (
"os"
"path/filepath"
"strings"
"sync"
"sync/atomic"
"syscall"
@ -185,3 +187,61 @@ func (rn *RootNode) openWriteOnlyFile(dirfd int, cName string, newFlags int) (rw
}()
return syscallcompat.Openat(dirfd, cName, newFlags, 0)
}
// openBackingDir opens the parent ciphertext directory of plaintext path
// "relPath". It returns the dirfd (opened with O_PATH) and the encrypted
// basename.
//
// The caller should then use Openat(dirfd, cName, ...) and friends.
// For convenience, if relPath is "", cName is going to be ".".
//
// openBackingDir is secure against symlink races by using Openat and
// ReadDirIVAt.
func (rn *RootNode) openBackingDir(relPath string) (dirfd int, cName string, err error) {
dirRelPath := nametransform.Dir(relPath)
// With PlaintextNames, we don't need to read DirIVs. Easy.
if rn.args.PlaintextNames {
dirfd, err = syscallcompat.OpenDirNofollow(rn.args.Cipherdir, dirRelPath)
if err != nil {
return -1, "", err
}
// If relPath is empty, cName is ".".
cName = filepath.Base(relPath)
return dirfd, cName, nil
}
// Open cipherdir (following symlinks)
dirfd, err = syscall.Open(rn.args.Cipherdir, syscall.O_DIRECTORY|syscallcompat.O_PATH, 0)
if err != nil {
return -1, "", err
}
// If relPath is empty, cName is ".".
if relPath == "" {
return dirfd, ".", nil
}
// Walk the directory tree
parts := strings.Split(relPath, "/")
for i, name := range parts {
iv, err := nametransform.ReadDirIVAt(dirfd)
if err != nil {
syscall.Close(dirfd)
return -1, "", err
}
cName, err = rn.nameTransform.EncryptAndHashName(name, iv)
if err != nil {
syscall.Close(dirfd)
return -1, "", err
}
// Last part? We are done.
if i == len(parts)-1 {
break
}
// Not the last part? Descend into next directory.
dirfd2, err := syscallcompat.Openat(dirfd, cName, syscall.O_NOFOLLOW|syscall.O_DIRECTORY|syscallcompat.O_PATH, 0)
syscall.Close(dirfd)
if err != nil {
return -1, "", err
}
dirfd = dirfd2
}
return dirfd, cName, nil
}