From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752720AbdGGJAI (ORCPT ); Fri, 7 Jul 2017 05:00:08 -0400 Received: from mga02.intel.com ([134.134.136.20]:55349 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751757AbdGGJAF (ORCPT ); Fri, 7 Jul 2017 05:00:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,321,1496127600"; d="scan'208";a="284084890" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, gregkh@linuxfoundation.org, akpm@linux-foundation.org, ebiederm@xmission.com, mingo@redhat.com, adobriyan@gmail.com, serge@hallyn.com, arozansk@redhat.com, dave@stgolabs.net, keescook@chromium.org, Elena Reshetova , Hans Liljestrand , David Windsor Subject: [PATCH 2/3] ipc: convert sem_undo_list.refcnt from atomic_t to refcount_t Date: Fri, 7 Jul 2017 11:59:51 +0300 Message-Id: <1499417992-3238-3-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1499417992-3238-1-git-send-email-elena.reshetova@intel.com> References: <1499417992-3238-1-git-send-email-elena.reshetova@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- ipc/sem.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/ipc/sem.c b/ipc/sem.c index 9e70cd7..d3ab140 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -122,7 +122,7 @@ struct sem_undo { * that may be shared among all a CLONE_SYSVSEM task group. */ struct sem_undo_list { - atomic_t refcnt; + refcount_t refcnt; spinlock_t lock; struct list_head list_proc; }; @@ -1642,7 +1642,7 @@ static inline int get_undo_list(struct sem_undo_list **undo_listp) if (undo_list == NULL) return -ENOMEM; spin_lock_init(&undo_list->lock); - atomic_set(&undo_list->refcnt, 1); + refcount_set(&undo_list->refcnt, 1); INIT_LIST_HEAD(&undo_list->list_proc); current->sysvsem.undo_list = undo_list; @@ -2041,7 +2041,7 @@ int copy_semundo(unsigned long clone_flags, struct task_struct *tsk) error = get_undo_list(&undo_list); if (error) return error; - atomic_inc(&undo_list->refcnt); + refcount_inc(&undo_list->refcnt); tsk->sysvsem.undo_list = undo_list; } else tsk->sysvsem.undo_list = NULL; @@ -2070,7 +2070,7 @@ void exit_sem(struct task_struct *tsk) return; tsk->sysvsem.undo_list = NULL; - if (!atomic_dec_and_test(&ulp->refcnt)) + if (!refcount_dec_and_test(&ulp->refcnt)) return; for (;;) { -- 2.7.4