From patchwork Mon Apr 26 15:45:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Davide Caratti X-Patchwork-Id: 428414 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=-16.0 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 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 98CEBC433B4 for ; Mon, 26 Apr 2021 15:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 548D16135A for ; Mon, 26 Apr 2021 15:46:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234117AbhDZPq7 (ORCPT ); Mon, 26 Apr 2021 11:46:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37905 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233923AbhDZPq6 (ORCPT ); Mon, 26 Apr 2021 11:46:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619451976; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7vBOvHcHI2oZqmZM5Aa2gGUzST69IcIGKxor2uO4AfE=; b=dLMOnbbZZ2GgAPal4swKuz4Q8Oz2pm6RioPZ8PArpY6yfbCHJ2AuUgZhOOX1EsCCiLmIxF t/qENffm2gozl2QCDggaHCIKTaRgDHfLcpFuMnlCWN0IeNYZK3jpsYxf0/ySk7WQ3cFVPU LXP8VPzpeINTWFLpCtZV7vh9+F5TWrQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-555-n4gEKu0mPo6RUeBd7L0vOw-1; Mon, 26 Apr 2021 11:46:12 -0400 X-MC-Unique: n4gEKu0mPo6RUeBd7L0vOw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 67B2A195D56E; Mon, 26 Apr 2021 15:46:04 +0000 (UTC) Received: from computer-6.station (unknown [10.40.192.86]) by smtp.corp.redhat.com (Postfix) with ESMTP id 91D85610A8; Mon, 26 Apr 2021 15:46:01 +0000 (UTC) From: Davide Caratti To: Jamal Hadi Salim , Cong Wang , Jiri Pirko , "David S. Miller" , Jakub Kicinski , wenxu , Marcelo Ricardo Leitner , Shuang Li Cc: netdev@vger.kernel.org Subject: [PATCH net] net/sched: act_ct: fix wild memory access when clearing fragments Date: Mon, 26 Apr 2021 17:45:51 +0200 Message-Id: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 --- 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 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a, 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);