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authorSebastian Lackner2017-11-28 01:02:11 +0100
committerrfjakob2017-11-28 09:28:06 +0100
commitad2720e0f939ce82605549bdb8c8479c285cb7df (patch)
tree2679efe7be372be510405b4e1f97147a988a8afb /internal
parent5a56810603ff9608c98d71cbfb8a6454da4c2261 (diff)
fusefrontend: allow_other: close race between symlink and chown
Fixes the same problem as described in 72b975867a3b9bdf53fc2da62e2ba4a328d7e4ab, except for symlinks instead of device nodes.
Diffstat (limited to 'internal')
-rw-r--r--internal/fusefrontend/fs.go21
1 files changed, 10 insertions, 11 deletions
diff --git a/internal/fusefrontend/fs.go b/internal/fusefrontend/fs.go
index 60d43f0..bb8e1cf 100644
--- a/internal/fusefrontend/fs.go
+++ b/internal/fusefrontend/fs.go
@@ -427,22 +427,20 @@ func (fs *FS) Symlink(target string, linkName string, context *fuse.Context) (co
if err != nil {
return fuse.ToStatus(err)
}
+ dirfd, err := os.Open(filepath.Dir(cPath))
+ if err != nil {
+ return fuse.ToStatus(err)
+ }
+ defer dirfd.Close()
var cTarget string = target
if !fs.args.PlaintextNames {
// Symlinks are encrypted like file contents (GCM) and base64-encoded
cBinTarget := fs.contentEnc.EncryptBlock([]byte(target), 0, nil)
cTarget = fs.nameTransform.B64.EncodeToString(cBinTarget)
}
- // Handle long file name
+ // Create ".name" file to store long file name (except in PlaintextNames mode)
cName := filepath.Base(cPath)
if !fs.args.PlaintextNames && nametransform.IsLongContent(cName) {
- var dirfd *os.File
- dirfd, err = os.Open(filepath.Dir(cPath))
- if err != nil {
- return fuse.ToStatus(err)
- }
- defer dirfd.Close()
- // Create ".name" file
err = fs.nameTransform.WriteLongName(dirfd, cName, linkName)
if err != nil {
return fuse.ToStatus(err)
@@ -454,16 +452,17 @@ func (fs *FS) Symlink(target string, linkName string, context *fuse.Context) (co
}
} else {
// Create symlink
- err = os.Symlink(cTarget, cPath)
+ err = syscallcompat.Symlinkat(cTarget, int(dirfd.Fd()), cName)
}
if err != nil {
return fuse.ToStatus(err)
}
// Set owner
if fs.args.PreserveOwner {
- err = os.Lchown(cPath, int(context.Owner.Uid), int(context.Owner.Gid))
+ err = syscallcompat.Fchownat(int(dirfd.Fd()), cName, int(context.Owner.Uid),
+ int(context.Owner.Gid), unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
- tlog.Warn.Printf("Mknod: Lchown failed: %v", err)
+ tlog.Warn.Printf("Symlink: Fchownat failed: %v", err)
}
}
return fuse.OK