internal/acl: use O_PATH descriptor

This avoids TOCTOU during hakurei_update_acl.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 17 insertions, 2 deletions

diff --git a/internal/acl/acl.go b/internal/acl/acl.go
index 7718ba3c..8b862ba2 100644
--- a/internal/acl/acl.go
+++ b/internal/acl/acl.go
@@ -7,7 +7,12 @@ package acl
 #include "libacl-helper.h"
 */
 import "C"
-import "os"
+
+import (
+	"os"
+
+	"hakurei.app/container"
+)
 
 // Perm represents acl_perm_t.
 type Perm C.acl_perm_t
@@ -83,11 +88,21 @@ func (e Error) Error() string {
 
 // Update replaces ACL_USER entry with qualifier uid.
 func Update(name string, uid int, perms Perm) error {
+	f, _err := os.OpenFile(name, container.O_PATH, 0)
+	if _err != nil {
+		return _err
+	}
+
 	r, err := C.hakurei_update_acl(
-		C.CString(name),
+		C.int(f.Fd()),
 		C.uid_t(uid),
 		C.acl_perm_t(perms),
 	)
+
+	if _err = f.Close(); _err != nil {
+		return _err
+	}
+
 	if r == C.HAKUREI_ACL_OK {
 		return nil
 	}