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 D1F64C4332F for ; Tue, 5 Apr 2022 09:52:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231864AbiDEJm3 (ORCPT ); Tue, 5 Apr 2022 05:42:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239180AbiDEITx (ORCPT ); Tue, 5 Apr 2022 04:19:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CC4D793A4; Tue, 5 Apr 2022 01:10:25 -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 7D5DA609D0; Tue, 5 Apr 2022 08:10:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F25CC385A2; Tue, 5 Apr 2022 08:10:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649146224; bh=vICWyt0gjqXcm0BpZVvzgSpeTKjQqJiq/T/zwqNvZcM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kyGwdK06YzR4mAFAPQ9DecB63hRuRcnSyayZouZkoX1kGJGEuJBUc3S+fw06SGraP 3DJN6Box+7l5ndEzxVL/rIdj+l0Kj6Ic/jWxwL9n6xrTpJvRaJ7R6KuvfXHGb6rJV5 jsSEqmVhn+00okzlOLSHpU0ECoWBmCMFCeLkR56Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , Yonglong Li , Mat Martineau , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.17 0688/1126] mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb Date: Tue, 5 Apr 2022 09:23:55 +0200 Message-Id: <20220405070427.809797140@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070407.513532867@linuxfoundation.org> References: <20220405070407.513532867@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: Yonglong Li [ Upstream commit 3ef3905aa3b5b3e222ee6eb0210bfd999417a8cc ] Got crash when doing pressure test of mptcp: =========================================================================== dst_release: dst:ffffa06ce6e5c058 refcnt:-1 kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle kernel paging request at ffffa06ce6e5c058 PGD 190a01067 P4D 190a01067 PUD 43fffb067 PMD 22e403063 PTE 8000000226e5c063 Oops: 0011 [#1] SMP PTI CPU: 7 PID: 7823 Comm: kworker/7:0 Kdump: loaded Tainted: G E Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.2.1 04/01/2014 Call Trace: ? skb_release_head_state+0x68/0x100 ? skb_release_all+0xe/0x30 ? kfree_skb+0x32/0xa0 ? mptcp_sendmsg_frag+0x57e/0x750 ? __mptcp_retrans+0x21b/0x3c0 ? __switch_to_asm+0x35/0x70 ? mptcp_worker+0x25e/0x320 ? process_one_work+0x1a7/0x360 ? worker_thread+0x30/0x390 ? create_worker+0x1a0/0x1a0 ? kthread+0x112/0x130 ? kthread_flush_work_fn+0x10/0x10 ? ret_from_fork+0x35/0x40 =========================================================================== In __mptcp_alloc_tx_skb skb was allocated and skb->tcp_tsorted_anchor will be initialized, in under memory pressure situation sk_wmem_schedule will return false and then kfree_skb. In this case skb->_skb_refdst is not null because_skb_refdst and tcp_tsorted_anchor are stored in the same mem, and kfree_skb will try to release dst and cause crash. Fixes: f70cad1085d1 ("mptcp: stop relying on tcp_tx_skb_cache") Reviewed-by: Paolo Abeni Signed-off-by: Yonglong Li Signed-off-by: Mat Martineau Link: https://lore.kernel.org/r/20220317220953.426024-1-mathew.j.martineau@linux.intel.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/mptcp/protocol.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 1c72f25f083e..014c9d88f947 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1196,6 +1196,7 @@ static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, g tcp_skb_entail(ssk, skb); return skb; } + tcp_skb_tsorted_anchor_cleanup(skb); kfree_skb(skb); return NULL; } -- 2.34.1