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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7054EC43619 for ; Mon, 12 Apr 2021 09:01:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31F1561352 for ; Mon, 12 Apr 2021 09:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238594AbhDLJB7 (ORCPT ); Mon, 12 Apr 2021 05:01:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:49838 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238854AbhDLI5x (ORCPT ); Mon, 12 Apr 2021 04:57:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F1E9561284; Mon, 12 Apr 2021 08:56:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618217819; bh=3DcSmrsaACPpic4DqciO1xIZX1a5iOCv9d4dHX3jeyo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BqoZ4oH6P9bnXZAC+G9j/jLyvfrrWRK9xEJNAMlUtOjT+BB++SNbZq2Y6e1Z8qFNm JEcMMfCx5ERISy1PX/gpowdkrC8SkyeMalSLR6pdrIsDOBAQYCJ58304zwuxWL/SXn nLuXF9vg5wm7+rX9TWcgvJ2SJ4R6MpeGkgzlJ2wk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Li Shuang , Xin Long , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 156/188] tipc: increment the tmp aead refcnt before attaching it Date: Mon, 12 Apr 2021 10:41:10 +0200 Message-Id: <20210412084018.816233010@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084013.643370347@linuxfoundation.org> References: <20210412084013.643370347@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: Xin Long [ Upstream commit 2a2403ca3add03f542f6b34bef9f74649969b06d ] Li Shuang found a NULL pointer dereference crash in her testing: [] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [] RIP: 0010:tipc_crypto_rcv_complete+0xc8/0x7e0 [tipc] [] Call Trace: [] [] tipc_crypto_rcv+0x2d9/0x8f0 [tipc] [] tipc_rcv+0x2fc/0x1120 [tipc] [] tipc_udp_recv+0xc6/0x1e0 [tipc] [] udpv6_queue_rcv_one_skb+0x16a/0x460 [] udp6_unicast_rcv_skb.isra.35+0x41/0xa0 [] ip6_protocol_deliver_rcu+0x23b/0x4c0 [] ip6_input+0x3d/0xb0 [] ipv6_rcv+0x395/0x510 [] __netif_receive_skb_core+0x5fc/0xc40 This is caused by NULL returned by tipc_aead_get(), and then crashed when dereferencing it later in tipc_crypto_rcv_complete(). This might happen when tipc_crypto_rcv_complete() is called by two threads at the same time: the tmp attached by tipc_crypto_key_attach() in one thread may be released by the one attached by that in the other thread. This patch is to fix it by incrementing the tmp's refcnt before attaching it instead of calling tipc_aead_get() after attaching it. Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication") Reported-by: Li Shuang Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/tipc/crypto.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c index 740ab9ae41a6..86eb6d679225 100644 --- a/net/tipc/crypto.c +++ b/net/tipc/crypto.c @@ -1934,12 +1934,13 @@ static void tipc_crypto_rcv_complete(struct net *net, struct tipc_aead *aead, goto rcv; if (tipc_aead_clone(&tmp, aead) < 0) goto rcv; + WARN_ON(!refcount_inc_not_zero(&tmp->refcnt)); if (tipc_crypto_key_attach(rx, tmp, ehdr->tx_key, false) < 0) { tipc_aead_free(&tmp->rcu); goto rcv; } tipc_aead_put(aead); - aead = tipc_aead_get(tmp); + aead = tmp; } if (unlikely(err)) { -- 2.30.2