From patchwork Fri Oct 20 07:23:47 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 10019063 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 03EA6603B5 for ; Fri, 20 Oct 2017 07:29:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E993A28EAC for ; Fri, 20 Oct 2017 07:29:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DD8E128ED0; Fri, 20 Oct 2017 07:29:07 +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 5D07128ECB for ; Fri, 20 Oct 2017 07:29:07 +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=WmKBchuRJLYHraQGbmZBHgQIQZcGagZ+Q6/YG4yo/qY=; b=g8ti5kdqzow2+Fhzx78jjvLzZ0 LQJ9EyaQdfCARPWMQUGg/8ckXu1DzMWVD0YLvP4XqCXLs6Kznxl8VFZX851mI6UHKk1j7oZ+6ie3P IWtFfKR5mv6YpoNLUO9ItqzX22x5mqZHm9yHXG+2nO+se044OyEcXEmvJCXAIzMAudXgTqi99fyTd JL0JMU6SQJtr0HGE9kdW18QRxknjzbD+ZvSr/QSEkFXOlhaMtPyMBFMO2BXgTBhH0vjQKonDYG83u 8pq3jCu00NiCH22sEVSZ+elZDDUR7wqyigVlbwkv+64+hbd2cSvpOQLvnEpl2yc3pCFK8W9ICe9pY u+HS5k+Q==; 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 1e5Rju-0000x6-Sa; Fri, 20 Oct 2017 07:29:06 +0000 Received: from mga05.intel.com ([192.55.52.43]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1e5Rh1-0006Eb-J4; Fri, 20 Oct 2017 07:26:28 +0000 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga105.fm.intel.com with ESMTP; 20 Oct 2017 00:25:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.43,405,1503385200"; d="scan'208";a="911831000" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.87]) by FMSMGA003.fm.intel.com with ESMTP; 20 Oct 2017 00:25:07 -0700 From: Elena Reshetova To: davem@davemloft.net Subject: [PATCH 13/15] drivers, net, ppp: convert ppp_file.refcnt from atomic_t to refcount_t Date: Fri, 20 Oct 2017 10:23:47 +0300 Message-Id: <1508484229-19706-14-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_002607_849716_ACCD5612 X-CRM114-Status: GOOD ( 12.28 ) 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 ppp_file.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/net/ppp/ppp_generic.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index e365866..6566107 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -51,6 +51,7 @@ #include #include #include +#include #include #include @@ -84,7 +85,7 @@ struct ppp_file { struct sk_buff_head xq; /* pppd transmit queue */ struct sk_buff_head rq; /* receive queue for pppd */ wait_queue_head_t rwait; /* for poll on reading /dev/ppp */ - atomic_t refcnt; /* # refs (incl /dev/ppp attached) */ + refcount_t refcnt; /* # refs (incl /dev/ppp attached) */ int hdrlen; /* space to leave for headers */ int index; /* interface unit / channel number */ int dead; /* unit/channel has been shut down */ @@ -408,7 +409,7 @@ static int ppp_release(struct inode *unused, struct file *file) unregister_netdevice(ppp->dev); rtnl_unlock(); } - if (atomic_dec_and_test(&pf->refcnt)) { + if (refcount_dec_and_test(&pf->refcnt)) { switch (pf->kind) { case INTERFACE: ppp_destroy_interface(PF_TO_PPP(pf)); @@ -881,7 +882,7 @@ static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, mutex_lock(&pn->all_ppp_mutex); ppp = ppp_find_unit(pn, unit); if (ppp) { - atomic_inc(&ppp->file.refcnt); + refcount_inc(&ppp->file.refcnt); file->private_data = &ppp->file; err = 0; } @@ -896,7 +897,7 @@ static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf, spin_lock_bh(&pn->all_channels_lock); chan = ppp_find_channel(pn, unit); if (chan) { - atomic_inc(&chan->file.refcnt); + refcount_inc(&chan->file.refcnt); file->private_data = &chan->file; err = 0; } @@ -1348,7 +1349,7 @@ static int ppp_dev_init(struct net_device *dev) * that ppp_destroy_interface() won't run before the device gets * unregistered. */ - atomic_inc(&ppp->file.refcnt); + refcount_inc(&ppp->file.refcnt); return 0; } @@ -1377,7 +1378,7 @@ static void ppp_dev_priv_destructor(struct net_device *dev) struct ppp *ppp; ppp = netdev_priv(dev); - if (atomic_dec_and_test(&ppp->file.refcnt)) + if (refcount_dec_and_test(&ppp->file.refcnt)) ppp_destroy_interface(ppp); } @@ -2676,7 +2677,7 @@ ppp_unregister_channel(struct ppp_channel *chan) pch->file.dead = 1; wake_up_interruptible(&pch->file.rwait); - if (atomic_dec_and_test(&pch->file.refcnt)) + if (refcount_dec_and_test(&pch->file.refcnt)) ppp_destroy_channel(pch); } @@ -3046,7 +3047,7 @@ init_ppp_file(struct ppp_file *pf, int kind) pf->kind = kind; skb_queue_head_init(&pf->xq); skb_queue_head_init(&pf->rq); - atomic_set(&pf->refcnt, 1); + refcount_set(&pf->refcnt, 1); init_waitqueue_head(&pf->rwait); } @@ -3164,7 +3165,7 @@ ppp_connect_channel(struct channel *pch, int unit) list_add_tail(&pch->clist, &ppp->channels); ++ppp->n_channels; pch->ppp = ppp; - atomic_inc(&ppp->file.refcnt); + refcount_inc(&ppp->file.refcnt); ppp_unlock(ppp); ret = 0; @@ -3195,7 +3196,7 @@ ppp_disconnect_channel(struct channel *pch) if (--ppp->n_channels == 0) wake_up_interruptible(&ppp->file.rwait); ppp_unlock(ppp); - if (atomic_dec_and_test(&ppp->file.refcnt)) + if (refcount_dec_and_test(&ppp->file.refcnt)) ppp_destroy_interface(ppp); err = 0; }