From patchwork Wed May 12 14:51:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 437803 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=-19.4 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 6CDFAC433B4 for ; Wed, 12 May 2021 17:06:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35965613C2 for ; Wed, 12 May 2021 17:06:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239178AbhELRGO (ORCPT ); Wed, 12 May 2021 13:06:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:46734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242592AbhELQuZ (ORCPT ); Wed, 12 May 2021 12:50:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EFB2A6023E; Wed, 12 May 2021 16:16:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620836194; bh=iOjIZm6la0AL6MPmYKkwAWVBvYQyp4J7fD8nBUcb92s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0xZPnRDQ3l44lO8vTOgTRc9lYkF1fYLzsHOSSqONnUni7c9WuO/gZtJqnNEu6euAe zrNCfuvhHEE7XN0n8+28q4BOD7bfkRB52Ms8k/jWrdIa0GY/qs2vSqWa1iv+fZD0IO xniy9/T0YHto/t3b6e4vRByy2Ne2IiIGrHvrZ8G0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shuang Li , Davide Caratti , "David S. Miller" , Sasha Levin Subject: [PATCH 5.12 649/677] net/sched: act_ct: fix wild memory access when clearing fragments Date: Wed, 12 May 2021 16:51:35 +0200 Message-Id: <20210512144858.923730385@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210512144837.204217980@linuxfoundation.org> References: <20210512144837.204217980@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Davide Caratti [ Upstream commit f77bd544a6bbe69aa50d9ed09f13494cf36ff806 ] while testing re-assembly/re-fragmentation using act_ct, it's possible to observe a crash like the following one: KASAN: maybe wild-memory-access in range [0x0001000000000448-0x000100000000044f] CPU: 50 PID: 0 Comm: swapper/50 Tainted: G S 5.12.0-rc7+ #424 Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.4.3 01/17/2017 RIP: 0010:inet_frag_rbtree_purge+0x50/0xc0 Code: 00 fc ff df 48 89 c3 31 ed 48 89 df e8 a9 7a 38 ff 4c 89 fe 48 89 df 49 89 c6 e8 5b 3a 38 ff 48 8d 7b 40 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 75 59 48 8d bb d0 00 00 00 4c 8b 6b 40 48 89 f8 48 RSP: 0018:ffff888c31449db8 EFLAGS: 00010203 RAX: 0000200000000089 RBX: 000100000000040e RCX: ffffffff989eb960 RDX: 0000000000000140 RSI: ffffffff97cfb977 RDI: 000100000000044e RBP: 0000000000000900 R08: 0000000000000000 R09: ffffed1186289350 R10: 0000000000000003 R11: ffffed1186289350 R12: dffffc0000000000 R13: 000100000000040e R14: 0000000000000000 R15: ffff888155e02160 FS: 0000000000000000(0000) GS:ffff888c31440000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005600cb70a5b8 CR3: 0000000a2c014005 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: inet_frag_destroy+0xa9/0x150 call_timer_fn+0x2d/0x180 run_timer_softirq+0x4fe/0xe70 __do_softirq+0x197/0x5a0 irq_exit_rcu+0x1de/0x200 sysvec_apic_timer_interrupt+0x6b/0x80 when act_ct temporarily stores an IP fragment, restoring the skb qdisc cb results in putting random data in FRAG_CB(), and this causes those "wild" memory accesses later, when the rbtree is purged. Never overwrite the skb cb in case tcf_ct_handle_fragments() returns -EINPROGRESS. Fixes: ae372cb1750f ("net/sched: act_ct: fix restore the qdisc_skb_cb after defrag") Fixes: 7baf2429a1a9 ("net/sched: cls_flower add CT_FLAGS_INVALID flag support") Reported-by: Shuang Li Signed-off-by: Davide Caratti Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sched/act_ct.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index 16e888a9601d..48fdf7293dea 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -732,7 +732,8 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb, #endif } - *qdisc_skb_cb(skb) = cb; + if (err != -EINPROGRESS) + *qdisc_skb_cb(skb) = cb; skb_clear_hash(skb); skb->ignore_df = 1; return err; @@ -967,7 +968,7 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a, err = tcf_ct_handle_fragments(net, skb, family, p->zone, &defrag); if (err == -EINPROGRESS) { retval = TC_ACT_STOLEN; - goto out; + goto out_clear; } if (err) goto drop; @@ -1030,7 +1031,6 @@ do_nat: out_push: skb_push_rcsum(skb, nh_ofs); -out: qdisc_skb_cb(skb)->post_ct = true; out_clear: tcf_action_update_bstats(&c->common, skb);