From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7A74C433F5 for ; Mon, 25 Oct 2021 19:39:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3A0E610C9 for ; Mon, 25 Oct 2021 19:39:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235173AbhJYTly (ORCPT ); Mon, 25 Oct 2021 15:41:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:53558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236618AbhJYTe7 (ORCPT ); Mon, 25 Oct 2021 15:34:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 54652610A6; Mon, 25 Oct 2021 19:31:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1635190297; bh=Ps6lIDaXjSpwSIMUsGNCTVWdQiy/a2kNcif61VQEJsI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=acm6vJM9COGAXxBRo63J4i2WwdA7nAVs9AQfL1+8FvnbMH2KACECx312HRckL2ece 4JGfZ2wfmZAuqm03nGm1P9mko7luCbk13KTjpJ2eHeNRoWyv15AzU0OX8fdVIlCKCV l3lkC/FYYZro+orBpywAQafI8EOEoe9Idqui/0/g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com, Ziyang Xuan , Oleksij Rempel , Marc Kleine-Budde Subject: [PATCH 5.10 40/95] can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv Date: Mon, 25 Oct 2021 21:14:37 +0200 Message-Id: <20211025191002.609165845@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211025190956.374447057@linuxfoundation.org> References: <20211025190956.374447057@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ziyang Xuan commit d9d52a3ebd284882f5562c88e55991add5d01586 upstream. It will trigger UAF for rx_kref of j1939_priv as following. cpu0 cpu1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ..... j1939_netdev_stop kref_put_lock(&priv->rx_kref, ...) kref_get(&priv->rx_kref, ...) REFCOUNT_WARN("addition on 0;...") ==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0 The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to protect. Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol") Link: https://lore.kernel.org/all/20210926104757.2021540-1-william.xuanziyang@huawei.com Cc: stable@vger.kernel.org Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan Acked-by: Oleksij Rempel Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/j1939/main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -249,11 +249,14 @@ struct j1939_priv *j1939_netdev_start(st struct j1939_priv *priv, *priv_new; int ret; - priv = j1939_priv_get_by_ndev(ndev); + spin_lock(&j1939_netdev_lock); + priv = j1939_priv_get_by_ndev_locked(ndev); if (priv) { kref_get(&priv->rx_kref); + spin_unlock(&j1939_netdev_lock); return priv; } + spin_unlock(&j1939_netdev_lock); priv = j1939_priv_create(ndev); if (!priv) @@ -269,10 +272,10 @@ struct j1939_priv *j1939_netdev_start(st /* Someone was faster than us, use their priv and roll * back our's. */ + kref_get(&priv_new->rx_kref); spin_unlock(&j1939_netdev_lock); dev_put(ndev); kfree(priv); - kref_get(&priv_new->rx_kref); return priv_new; } j1939_priv_set(ndev, priv);