From patchwork Fri Oct 20 07:23:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 10019065 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7BAF2602CB for ; Fri, 20 Oct 2017 07:29:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6CFF128DD5 for ; Fri, 20 Oct 2017 07:29:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 606A228E8E; Fri, 20 Oct 2017 07:29:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, RCVD_IN_DNSWL_MED, RCVD_IN_SORBS_SPAM autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E343828DD5 for ; Fri, 20 Oct 2017 07:29:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=tduhmdvlFjnvzrQCHkwccdQp6FnAsoc07K+c5H1XDsY=; b=HcVeDg4YM8yN3RULbj40rWkABb dfKz3U/3WuzSQVoNEPFLwH7vRYFGToUx61uyoK171jlSf5m7tf4yae8O8DO1laAUF1hBJgm3UutLe nr1gfEnGMlbtxDtzTcQV3r67I41HVuRlYXe4xR5FAHgzoqGg/dfEMfzlAuU/5+oBHKLdq0qDb4sbv AsnjXtem42amAf5gOWVswfF9QlPlfv1bPV8fgVz/ZE+wYXPJSI/cCnfDBKzBND9THPGFMC9sACi0V Wn3Nl6AsSJ3di91Qy77fCvdWAK1Y+kRISTOPLSY+t7QFnMsUu1No4VopWHSRK/c2bUZbIUFKDvgdH nmH7FuAw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1e5RkD-0001C5-7L; Fri, 20 Oct 2017 07:29:25 +0000 Received: from mga07.intel.com ([134.134.136.100]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1e5RhN-0007F8-Mb; Fri, 20 Oct 2017 07:27:35 +0000 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP; 20 Oct 2017 00:25:51 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.43,405,1503385200"; d="scan'208";a="911831139" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.87]) by FMSMGA003.fm.intel.com with ESMTP; 20 Oct 2017 00:25:26 -0700 From: Elena Reshetova To: davem@davemloft.net Subject: [PATCH 15/15] drivers, connector: convert cn_callback_entry.refcnt from atomic_t to refcount_t Date: Fri, 20 Oct 2017 10:23:49 +0300 Message-Id: <1508484229-19706-16-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1508484229-19706-1-git-send-email-elena.reshetova@intel.com> References: <1508484229-19706-1-git-send-email-elena.reshetova@intel.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171020_002630_096080_A7348756 X-CRM114-Status: GOOD ( 10.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peterz@infradead.org, matanb@mellanox.com, paulus@samba.org, zbr@ioremap.net, Elena Reshetova , nbd@openwrt.org, linux-rdma@vger.kernel.org, saeedm@mellanox.com, ganeshgr@chelsio.com, ajk@comnets.uni-bremen.de, keescook@chromium.org, sean.wang@mediatek.com, leonro@mellanox.com, linux-mediatek@lists.infradead.org, john@phrozen.org, matthias.bgg@gmail.com, linux-hams@vger.kernel.org, linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org, yishaih@mellanox.com, linux-kernel@vger.kernel.org, linux-ppp@vger.kernel.org, tariqt@mellanox.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable cn_callback_entry.refcnt is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova --- drivers/connector/cn_queue.c | 4 ++-- drivers/connector/connector.c | 2 +- include/linux/connector.h | 4 ++-- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c index 1f8bf05..9c54fdf 100644 --- a/drivers/connector/cn_queue.c +++ b/drivers/connector/cn_queue.c @@ -45,7 +45,7 @@ cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name, return NULL; } - atomic_set(&cbq->refcnt, 1); + refcount_set(&cbq->refcnt, 1); atomic_inc(&dev->refcnt); cbq->pdev = dev; @@ -58,7 +58,7 @@ cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name, void cn_queue_release_callback(struct cn_callback_entry *cbq) { - if (!atomic_dec_and_test(&cbq->refcnt)) + if (!refcount_dec_and_test(&cbq->refcnt)) return; atomic_dec(&cbq->pdev->refcnt); diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c index 25693b0..8615594b 100644 --- a/drivers/connector/connector.c +++ b/drivers/connector/connector.c @@ -157,7 +157,7 @@ static int cn_call_callback(struct sk_buff *skb) spin_lock_bh(&dev->cbdev->queue_lock); list_for_each_entry(i, &dev->cbdev->queue_list, callback_entry) { if (cn_cb_equal(&i->id.id, &msg->id)) { - atomic_inc(&i->refcnt); + refcount_inc(&i->refcnt); cbq = i; break; } diff --git a/include/linux/connector.h b/include/linux/connector.h index f8fe863..032102b 100644 --- a/include/linux/connector.h +++ b/include/linux/connector.h @@ -22,7 +22,7 @@ #define __CONNECTOR_H -#include +#include #include #include @@ -49,7 +49,7 @@ struct cn_callback_id { struct cn_callback_entry { struct list_head callback_entry; - atomic_t refcnt; + refcount_t refcnt; struct cn_queue_dev *pdev; struct cn_callback_id id;