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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5762BC4332F for ; Mon, 14 Mar 2022 12:20:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232673AbiCNMVl (ORCPT ); Mon, 14 Mar 2022 08:21:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241282AbiCNMRH (ORCPT ); Mon, 14 Mar 2022 08:17:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4ACB33615B; Mon, 14 Mar 2022 05:12:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BC08461315; Mon, 14 Mar 2022 12:12:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DA05C340E9; Mon, 14 Mar 2022 12:12:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647259933; bh=RpuEEhblVS7oeVMwXLKhwEPjAiZgZESDzNGYsLkFL/c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s0CnPijFfoTAiKbWCmO62hfc3OIn1pb8Mj2THxoKm/F/W6e+YXpYObygAx41vSLP0 6EPtBzTPTYvsl4/ztk6zI4Jyonj15Uh1kGxaJQsaCNHakgfZDzr1GwODSc9iHbS6fe RGP3xx6RN19MHdkc1UmvAl+DY0IRWyPT8iCRSnaw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shuang Li , Jon Maloy , Tung Nguyen , "David S. Miller" , Sasha Levin Subject: [PATCH 5.16 012/121] tipc: fix kernel panic when enabling bearer Date: Mon, 14 Mar 2022 12:53:15 +0100 Message-Id: <20220314112744.468877112@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220314112744.120491875@linuxfoundation.org> References: <20220314112744.120491875@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: stable@vger.kernel.org From: Tung Nguyen [ Upstream commit be4977b847f5d5cedb64d50eaaf2218c3a55a3a3 ] When enabling a bearer on a node, a kernel panic is observed: [ 4.498085] RIP: 0010:tipc_mon_prep+0x4e/0x130 [tipc] ... [ 4.520030] Call Trace: [ 4.520689] [ 4.521236] tipc_link_build_proto_msg+0x375/0x750 [tipc] [ 4.522654] tipc_link_build_state_msg+0x48/0xc0 [tipc] [ 4.524034] __tipc_node_link_up+0xd7/0x290 [tipc] [ 4.525292] tipc_rcv+0x5da/0x730 [tipc] [ 4.526346] ? __netif_receive_skb_core+0xb7/0xfc0 [ 4.527601] tipc_l2_rcv_msg+0x5e/0x90 [tipc] [ 4.528737] __netif_receive_skb_list_core+0x20b/0x260 [ 4.530068] netif_receive_skb_list_internal+0x1bf/0x2e0 [ 4.531450] ? dev_gro_receive+0x4c2/0x680 [ 4.532512] napi_complete_done+0x6f/0x180 [ 4.533570] virtnet_poll+0x29c/0x42e [virtio_net] ... The node in question is receiving activate messages in another thread after changing bearer status to allow message sending/ receiving in current thread: thread 1 | thread 2 -------- | -------- | tipc_enable_bearer() | test_and_set_bit_lock() | tipc_bearer_xmit_skb() | | tipc_l2_rcv_msg() | tipc_rcv() | __tipc_node_link_up() | tipc_link_build_state_msg() | tipc_link_build_proto_msg() | tipc_mon_prep() | { | ... | // null-pointer dereference | u16 gen = mon->dom_gen; | ... | } // Not being executed yet | tipc_mon_create() | { | ... | // allocate | mon = kzalloc(); | ... | } | Monitoring pointer in thread 2 is dereferenced before monitoring data is allocated in thread 1. This causes kernel panic. This commit fixes it by allocating the monitoring data before enabling the bearer to receive messages. Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework") Reported-by: Shuang Li Acked-by: Jon Maloy Signed-off-by: Tung Nguyen Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/tipc/bearer.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 60bc74b76adc..1cb5907d90d8 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -352,16 +352,18 @@ static int tipc_enable_bearer(struct net *net, const char *name, goto rejected; } - test_and_set_bit_lock(0, &b->up); - rcu_assign_pointer(tn->bearer_list[bearer_id], b); - if (skb) - tipc_bearer_xmit_skb(net, bearer_id, skb, &b->bcast_addr); - + /* Create monitoring data before accepting activate messages */ if (tipc_mon_create(net, bearer_id)) { bearer_disable(net, b); + kfree_skb(skb); return -ENOMEM; } + test_and_set_bit_lock(0, &b->up); + rcu_assign_pointer(tn->bearer_list[bearer_id], b); + if (skb) + tipc_bearer_xmit_skb(net, bearer_id, skb, &b->bcast_addr); + pr_info("Enabled bearer <%s>, priority %u\n", name, prio); return res; -- 2.34.1