linux-kernel - [PATCH 05/12] ipc/util.c: correct comment in ipc_obtain_object

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180709151019.1336-6-manfred@colorfullife.com>
Date:   Mon,  9 Jul 2018 17:10:12 +0200
From:   Manfred Spraul <manfred@...orfullife.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Davidlohr Bueso <dave@...olabs.net>,
        Dmitry Vyukov <dvyukov@...gle.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, 1vier1@....de,
        Kees Cook <keescook@...omium.org>,
        Manfred Spraul <manfred@...orfullife.com>
Subject: [PATCH 05/12] ipc/util.c: correct comment in ipc_obtain_object_check

The comment that explains ipc_obtain_object_check is wrong:
The function checks the sequence number, not the reference
counter.
Note that checking the reference counter would be meaningless:
The reference counter is decreased without holding any locks,
thus an object with kern_ipc_perm.deleted=true may disappear at
the end of the next rcu grace period.

Signed-off-by: Manfred Spraul <manfred@...orfullife.com>
Cc: Davidlohr Bueso <dave@...olabs.net>
---
 ipc/util.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ipc/util.c b/ipc/util.c
index bbb1ce212a0d..8133f10832a9 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -644,8 +644,8 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
  * @ids: ipc identifier set
  * @id: ipc id to look for
  *
- * Similar to ipc_obtain_object_idr() but also checks
- * the ipc object reference counter.
+ * Similar to ipc_obtain_object_idr() but also checks the ipc object
+ * sequence number.
  *
  * Call inside the RCU critical section.
  * The ipc object is *not* locked on exit.
-- 
2.17.1