From patchwork Wed Aug 31 13:22:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Soenke Huster X-Patchwork-Id: 12960719 X-Patchwork-Delegate: johannes@sipsolutions.net 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDC52ECAAD4 for ; Wed, 31 Aug 2022 13:30:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231356AbiHaNaE (ORCPT ); Wed, 31 Aug 2022 09:30:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229629AbiHaNaD (ORCPT ); Wed, 31 Aug 2022 09:30:03 -0400 X-Greylist: delayed 402 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 31 Aug 2022 06:29:59 PDT Received: from giacobini.uberspace.de (giacobini.uberspace.de [185.26.156.129]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D4C31A3B6 for ; Wed, 31 Aug 2022 06:29:57 -0700 (PDT) Received: (qmail 15005 invoked by uid 990); 31 Aug 2022 13:23:14 -0000 Authentication-Results: giacobini.uberspace.de; auth=pass (plain) From: Soenke Huster To: Johannes Berg , Kalle Valo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Soenke Huster , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] wifi: mac80211_hwsim: check length for virtio packets Date: Wed, 31 Aug 2022 15:22:06 +0200 Message-Id: <20220831132205.129922-1-soenke.huster@eknoes.de> X-Mailer: git-send-email 2.37.3 MIME-Version: 1.0 X-Rspamd-Bar: / X-Rspamd-Report: R_MISSING_CHARSET(0.5) MIME_GOOD(-0.1) MID_CONTAINS_FROM(1) BAYES_HAM(-0.616589) X-Rspamd-Score: 0.78341 Received: from unknown (HELO unkown) (::1) by giacobini.uberspace.de (Haraka/2.8.28) with ESMTPSA; Wed, 31 Aug 2022 15:23:14 +0200 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org An invalid packet with a length shorther than the specified length in the netlink header can lead to use-after-frees and slab-out-of-bounds in the processing of the netlink attributes, such as the following: BUG: KASAN: slab-out-of-bounds in __nla_validate_parse+0x1258/0x2010 Read of size 2 at addr ffff88800ac7952c by task kworker/0:1/12 Workqueue: events hwsim_virtio_rx_work Call Trace: dump_stack_lvl+0x45/0x5d print_report.cold+0x5e/0x5e5 kasan_report+0xb1/0x1c0 __nla_validate_parse+0x1258/0x2010 __nla_parse+0x22/0x30 hwsim_virtio_handle_cmd.isra.0+0x13f/0x2d0 hwsim_virtio_rx_work+0x1b2/0x370 process_one_work+0x8df/0x1530 worker_thread+0x575/0x11a0 kthread+0x29d/0x340 ret_from_fork+0x22/0x30 Discarding packets with an invalid length solves this. Therefore, skb->len must be set at reception. Signed-off-by: Soenke Huster --- drivers/net/wireless/mac80211_hwsim.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index 4fb8f68e5c3b..6bd9bd50071e 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -5436,6 +5436,10 @@ static int hwsim_virtio_handle_cmd(struct sk_buff *skb) nlh = nlmsg_hdr(skb); gnlh = nlmsg_data(nlh); + + if (skb->len < nlh->nlmsg_len) + return -EINVAL; + err = genlmsg_parse(nlh, &hwsim_genl_family, tb, HWSIM_ATTR_MAX, hwsim_genl_policy, NULL); if (err) { @@ -5478,7 +5482,8 @@ static void hwsim_virtio_rx_work(struct work_struct *work) spin_unlock_irqrestore(&hwsim_virtio_lock, flags); skb->data = skb->head; - skb_set_tail_pointer(skb, len); + skb_reset_tail_pointer(skb); + skb_put(skb, len); hwsim_virtio_handle_cmd(skb); spin_lock_irqsave(&hwsim_virtio_lock, flags);