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authorJakob Unterwurzacher2017-04-29 14:15:13 +0200
committerJakob Unterwurzacher2017-04-29 14:15:13 +0200
commit7d38f80a78644c8ec4900cc990bfb894387112ed (patch)
treeef93c700d0a62135ad6e77463637bdea733f8479 /internal/nametransform/diriv.go
parent3409ade2723d931097560fbbe35e461553c5912c (diff)
nametransform: WriteDirIV: replace ioutil.WriteFile
As reported at https://github.com/rfjakob/gocryptfs/issues/105 , the "ioutil.WriteFile(file, iv, 0400)" call causes "permissions denied" errors on an NFSv4 setup. "strace"ing diriv creation and gocryptfs.conf creation shows this: conf (works on the user's NFSv4 mount): openat(AT_FDCWD, "/tmp/a/gocryptfs.conf.tmp", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0400) = 3 diriv (fails): openat(AT_FDCWD, "/tmp/a/gocryptfs.diriv", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0400) = 3 This patch creates the diriv file with the same flags that are used for creating the conf: openat(AT_FDCWD, "/tmp/a/gocryptfs.diriv", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0400) = 3 Closes https://github.com/rfjakob/gocryptfs/issues/105
Diffstat (limited to 'internal/nametransform/diriv.go')
-rw-r--r--internal/nametransform/diriv.go20
1 files changed, 16 insertions, 4 deletions
diff --git a/internal/nametransform/diriv.go b/internal/nametransform/diriv.go
index e4670c8..00d059f 100644
--- a/internal/nametransform/diriv.go
+++ b/internal/nametransform/diriv.go
@@ -2,7 +2,6 @@ package nametransform
import (
"io"
- "io/ioutil"
"os"
"path/filepath"
"strings"
@@ -71,11 +70,24 @@ func fdReadDirIV(fd *os.File) (iv []byte, err error) {
func WriteDirIV(dir string) error {
iv := cryptocore.RandBytes(DirIVLen)
file := filepath.Join(dir, DirIVFilename)
- err := ioutil.WriteFile(file, iv, 0400)
+ // 0400 permissions: gocryptfs.diriv should never be modified after creation.
+ // Don't use "ioutil.WriteFile", it causes trouble on NFS: https://github.com/rfjakob/gocryptfs/issues/105
+ fd, err := os.OpenFile(file, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0400)
if err != nil {
- tlog.Warn.Printf("WriteDirIV: %v", err)
+ tlog.Warn.Printf("WriteDirIV: OpenFile: %v", err)
+ return err
}
- return err
+ _, err = fd.Write(iv)
+ if err != nil {
+ tlog.Warn.Printf("WriteDirIV: Write: %v", err)
+ return err
+ }
+ err = fd.Close()
+ if err != nil {
+ tlog.Warn.Printf("WriteDirIV: Close: %v", err)
+ return err
+ }
+ return nil
}
// EncryptPathDirIV - encrypt relative plaintext path using EME with DirIV.