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authorJakob Unterwurzacher2018-10-14 20:11:49 +0200
committerJakob Unterwurzacher2019-01-01 16:24:09 +0100
commit932efbd4593fe6be6c86f0dafeaea32910b7c246 (patch)
treea950de9c1434a180f9b6f908d522d8222cecb768 /internal/fusefrontend/names.go
parent0e2e7c13cfc6d37f2521db99bf0393c37a5549d6 (diff)
fusefrontend: make openBackingDir() symlink-safe
openBackingDir() used encryptPath(), which is not symlink-safe itself. Drop encryptPath() and implement our own directory walk. Adds three seconds to untar and two seconds to rm: $ ./benchmark.bash Testing gocryptfs at /tmp/benchmark.bash.MzG: gocryptfs v1.6-36-g8fb3c2f-dirty; go-fuse v20170619-66-g6df8ddc; 2018-10-14 go1.11 WRITE: 262144000 bytes (262 MB, 250 MiB) copied, 1.25078 s, 210 MB/s READ: 262144000 bytes (262 MB, 250 MiB) copied, 1.0318 s, 254 MB/s UNTAR: 20.941 MD5: 11.568 LS: 1.638 RM: 5.337
Diffstat (limited to 'internal/fusefrontend/names.go')
-rw-r--r--internal/fusefrontend/names.go51
1 files changed, 44 insertions, 7 deletions
diff --git a/internal/fusefrontend/names.go b/internal/fusefrontend/names.go
index 3bf64d5..5ec252b 100644
--- a/internal/fusefrontend/names.go
+++ b/internal/fusefrontend/names.go
@@ -4,8 +4,11 @@ package fusefrontend
import (
"path/filepath"
+ "strings"
+ "syscall"
"github.com/rfjakob/gocryptfs/internal/configfile"
+ "github.com/rfjakob/gocryptfs/internal/nametransform"
"github.com/rfjakob/gocryptfs/internal/syscallcompat"
"github.com/rfjakob/gocryptfs/internal/tlog"
)
@@ -42,19 +45,53 @@ func (fs *FS) getBackingPath(relPath string) (string, error) {
// openBackingDir opens the parent ciphertext directory of plaintext path
// "relPath" and returns the dirfd and the encrypted basename.
+//
// The caller should then use Openat(dirfd, cName, ...) and friends.
-// openBackingDir is secure against symlink races.
+// For convenience, if relPath is "", cName is going to be ".".
+//
+// openBackingDir is secure against symlink races by using Openat and
+// ReadDirIVAt.
func (fs *FS) openBackingDir(relPath string) (dirfd int, cName string, err error) {
- cRelPath, err := fs.encryptPath(relPath)
- if err != nil {
- return -1, "", err
+ // With PlaintextNames, we don't need to read DirIVs. Easy.
+ if fs.args.PlaintextNames {
+ dir := nametransform.Dir(relPath)
+ dirfd, err = syscallcompat.OpenDirNofollow(fs.args.Cipherdir, dir)
+ if err != nil {
+ return -1, "", err
+ }
+ // If relPath is empty, cName is ".".
+ cName = filepath.Base(relPath)
+ return dirfd, cName, nil
}
- // Open parent dir
- dirfd, err = syscallcompat.OpenDirNofollow(fs.args.Cipherdir, filepath.Dir(cRelPath))
+ // Open cipherdir (following symlinks)
+ dirfd, err = syscall.Open(fs.args.Cipherdir, syscall.O_RDONLY|syscall.O_DIRECTORY|syscallcompat.O_PATH, 0)
if err != nil {
return -1, "", err
}
- cName = filepath.Base(cRelPath)
+ // 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 {
+ return -1, "", err
+ }
+ cName = fs.nameTransform.EncryptAndHashName(name, iv)
+ // 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_RDONLY|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
}