diff --git a/src/vma2pbs.rs b/src/vma2pbs.rs
index 0d96ace..199cf50 100644
--- a/src/vma2pbs.rs
+++ b/src/vma2pbs.rs
@@ -71,11 +71,18 @@ fn create_pbs_backup_task(args: BackupVmaToPbsArgs) -> Result<*mut ProxmoxBackup
     let pbs_password_cstr = CString::new(args.pbs_password)?;
     let fingerprint_cstr = CString::new(args.fingerprint)?;
     let keyfile_cstr = args.keyfile.map(|v| CString::new(v).unwrap());
-    let keyfile_ptr = keyfile_cstr.map(|v| v.as_ptr()).unwrap_or(ptr::null());
+    let keyfile_ptr = keyfile_cstr
+        .as_ref()
+        .map(|v| v.as_ptr())
+        .unwrap_or(ptr::null());
     let key_password_cstr = args.key_password.map(|v| CString::new(v).unwrap());
-    let key_password_ptr = key_password_cstr.map(|v| v.as_ptr()).unwrap_or(ptr::null());
+    let key_password_ptr = key_password_cstr
+        .as_ref()
+        .map(|v| v.as_ptr())
+        .unwrap_or(ptr::null());
     let master_keyfile_cstr = args.master_keyfile.map(|v| CString::new(v).unwrap());
     let master_keyfile_ptr = master_keyfile_cstr
+        .as_ref()
         .map(|v| v.as_ptr())
         .unwrap_or(ptr::null());