Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932314AbdCFOe6 (ORCPT ); Mon, 6 Mar 2017 09:34:58 -0500 Received: from mga03.intel.com ([134.134.136.65]:47292 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752935AbdCFOY4 (ORCPT ); Mon, 6 Mar 2017 09:24:56 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72746508" From: Elena Reshetova To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux1394-devel@lists.sourceforge.net, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-media@vger.kernel.org, devel@linuxdriverproject.org, linux-pci@vger.kernel.org, linux-s390@vger.kernel.org, fcoe-devel@open-fcoe.org, linux-scsi@vger.kernel.org, open-iscsi@googlegroups.com, devel@driverdev.osuosl.org, target-devel@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, peterz@infradead.org, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 25/29] drivers, usb: convert ffs_data.ref from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:21:12 +0200 Message-Id: <1488810076-3754-26-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> References: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2300 Lines: 77 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 --- drivers/usb/gadget/function/f_fs.c | 8 ++++---- drivers/usb/gadget/function/u_fs.h | 3 ++- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 87fccf6..3cdeb91 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1570,14 +1570,14 @@ static void ffs_data_get(struct ffs_data *ffs) { ENTER(); - atomic_inc(&ffs->ref); + refcount_inc(&ffs->ref); } static void ffs_data_opened(struct ffs_data *ffs) { ENTER(); - atomic_inc(&ffs->ref); + refcount_inc(&ffs->ref); if (atomic_add_return(1, &ffs->opened) == 1 && ffs->state == FFS_DEACTIVATED) { ffs->state = FFS_CLOSING; @@ -1589,7 +1589,7 @@ static void ffs_data_put(struct ffs_data *ffs) { ENTER(); - if (unlikely(atomic_dec_and_test(&ffs->ref))) { + if (unlikely(refcount_dec_and_test(&ffs->ref))) { pr_info("%s(): freeing\n", __func__); ffs_data_clear(ffs); BUG_ON(waitqueue_active(&ffs->ev.waitq) || @@ -1634,7 +1634,7 @@ static struct ffs_data *ffs_data_new(void) ENTER(); - atomic_set(&ffs->ref, 1); + refcount_set(&ffs->ref, 1); atomic_set(&ffs->opened, 0); ffs->state = FFS_READ_DESCRIPTORS; mutex_init(&ffs->mutex); diff --git a/drivers/usb/gadget/function/u_fs.h b/drivers/usb/gadget/function/u_fs.h index 4b69694..abfca48 100644 --- a/drivers/usb/gadget/function/u_fs.h +++ b/drivers/usb/gadget/function/u_fs.h @@ -20,6 +20,7 @@ #include #include #include +#include #ifdef VERBOSE_DEBUG #ifndef pr_vdebug @@ -177,7 +178,7 @@ struct ffs_data { struct completion ep0req_completion; /* P: mutex */ /* reference counter */ - atomic_t ref; + refcount_t ref; /* how many files are opened (EP0 and others) */ atomic_t opened; -- 2.7.4