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 25BBDC6FD1D for ; Wed, 15 Mar 2023 06:20:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230461AbjCOGUR (ORCPT ); Wed, 15 Mar 2023 02:20:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229506AbjCOGUP (ORCPT ); Wed, 15 Mar 2023 02:20:15 -0400 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FA7332513; Tue, 14 Mar 2023 23:19:45 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id a2so18979768plm.4; Tue, 14 Mar 2023 23:19:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678861183; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=n/OrkxmmE5cofD38xOKyNzOSC79HG80Mp2FvP2njW1E=; b=elz9SoI2z4hvoF0E7Fce9e9Uzt1L5mPVGUle0Z2GRL7GKHNdpR1WClOwsOMMfRcfLb Qm5bEwBZiurpqERUtTouZz2S3a36VBgLLIOMkqSKnMrMJ3b9P+G5KxjBKceLJ4Jicv7s aqU/qzrAvRBerY1tWopPtiFfLgq9YSrKIZfKiVjR5Lx0bKLX3MEmXpMvD8XJ47pRckMW LQ4T6E2i+sa9iJtFuLcFtfp3fuBE6GvUMHObkgYqPmPRqdbcxD2vnMKd9k6PCWBCr9Xh HbqSTBPM9NZhM8reWkzkGGo3SuKsntZM5rQSAyOjswwKoB2SvmOsohhR+Fbt2PA1h5Gk Z/7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678861183; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=n/OrkxmmE5cofD38xOKyNzOSC79HG80Mp2FvP2njW1E=; b=ybsT2yJobisenQJCb5wmp1SueOX4L3FAxesUPCUhyvvyu7HXhoPwXQO++NQ2Iy68Ek 5nZSbLEQMaxxMVgyjkxNBGDekhi5nRLfNqPBkxml07edSmVL5Mf00xEalrPolakZLUER tKLv/MvnZPB8FXq4aokX3jglMGfpnMSVfwxzI/Ggjobwjvh+bryK5s0UjCmbOMTQhwZj Ln7umszArmamlIm2yq/CFwhblIPMdQGVOgssS3qXkwUBhzzl4REegjQfnetQHkf+PonI cjeJlxRQujdHZLQqD7kaj4LN1Ts+gjpJzgDiWKtJm4BjaoarlZsbRIL0ocgYP3el9+lP xGcQ== X-Gm-Message-State: AO0yUKWVmbIWVlq7ogGT80cofI+RyjEypC0VPvUz+9nTp7U+sybx/UJo csIWWVc48aQciRw+sFETqbU= X-Google-Smtp-Source: AK7set/LFAsj6/iIWE9gzOEUjb45Y4FkKnpHnR2Jt7wH+U+1xLYc1zBO5MBoiW9zydE2UyZR6mw5Sw== X-Received: by 2002:a17:90b:688:b0:23d:4229:f7d7 with SMTP id m8-20020a17090b068800b0023d4229f7d7mr3465450pjz.38.1678861182899; Tue, 14 Mar 2023 23:19:42 -0700 (PDT) Received: from [192.168.99.21] (i114-182-247-24.s42.a013.ap.plala.or.jp. [114.182.247.24]) by smtp.googlemail.com with ESMTPSA id ko12-20020a17090307cc00b0019aaba5c90bsm2769732plb.84.2023.03.14.23.19.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Mar 2023 23:19:42 -0700 (PDT) Message-ID: <6926d4f1-18d3-98e0-ac8a-8478d4020dab@gmail.com> Date: Wed, 15 Mar 2023 15:19:37 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH] veth: Fix use after free in XDP_REDIRECT To: Shawn Bohrer Cc: toke@kernel.org, makita.toshiaki@lab.ntt.co.jp, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@cloudflare.com, lorenzo@kernel.org References: <20230314153351.2201328-1-sbohrer@cloudflare.com> Content-Language: en-US From: Toshiaki Makita In-Reply-To: <20230314153351.2201328-1-sbohrer@cloudflare.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2023/03/15 0:33, Shawn Bohrer wrote: > 718a18a0c8a67f97781e40bdef7cdd055c430996 "veth: Rework veth_xdp_rcv_skb > in order to accept non-linear skb" introduced a bug where it tried to > use pskb_expand_head() if the headroom was less than > XDP_PACKET_HEADROOM. This however uses kmalloc to expand the head, > which will later allow consume_skb() to free the skb while is it still > in use by AF_XDP. > > Previously if the headroom was less than XDP_PACKET_HEADROOM we > continued on to allocate a new skb from pages so this restores that > behavior. > > BUG: KASAN: use-after-free in __xsk_rcv+0x18d/0x2c0 > Read of size 78 at addr ffff888976250154 by task napi/iconduit-g/148640 > > CPU: 5 PID: 148640 Comm: napi/iconduit-g Kdump: loaded Tainted: G O 6.1.4-cloudflare-kasan-2023.1.2 #1 > Hardware name: Quanta Computer Inc. QuantaPlex T41S-2U/S2S-MB, BIOS S2S_3B10.03 06/21/2018 > Call Trace: > > dump_stack_lvl+0x34/0x48 > print_report+0x170/0x473 > ? __xsk_rcv+0x18d/0x2c0 > kasan_report+0xad/0x130 > ? __xsk_rcv+0x18d/0x2c0 > kasan_check_range+0x149/0x1a0 > memcpy+0x20/0x60 > __xsk_rcv+0x18d/0x2c0 > __xsk_map_redirect+0x1f3/0x490 > ? veth_xdp_rcv_skb+0x89c/0x1ba0 [veth] > xdp_do_redirect+0x5ca/0xd60 > veth_xdp_rcv_skb+0x935/0x1ba0 [veth] > ? __netif_receive_skb_list_core+0x671/0x920 > ? veth_xdp+0x670/0x670 [veth] > veth_xdp_rcv+0x304/0xa20 [veth] > ? do_xdp_generic+0x150/0x150 > ? veth_xdp_rcv_one+0xde0/0xde0 [veth] > ? _raw_spin_lock_bh+0xe0/0xe0 > ? newidle_balance+0x887/0xe30 > ? __perf_event_task_sched_in+0xdb/0x800 > veth_poll+0x139/0x571 [veth] > ? veth_xdp_rcv+0xa20/0xa20 [veth] > ? _raw_spin_unlock+0x39/0x70 > ? finish_task_switch.isra.0+0x17e/0x7d0 > ? __switch_to+0x5cf/0x1070 > ? __schedule+0x95b/0x2640 > ? io_schedule_timeout+0x160/0x160 > __napi_poll+0xa1/0x440 > napi_threaded_poll+0x3d1/0x460 > ? __napi_poll+0x440/0x440 > ? __kthread_parkme+0xc6/0x1f0 > ? __napi_poll+0x440/0x440 > kthread+0x2a2/0x340 > ? kthread_complete_and_exit+0x20/0x20 > ret_from_fork+0x22/0x30 > > > Freed by task 148640: > kasan_save_stack+0x23/0x50 > kasan_set_track+0x21/0x30 > kasan_save_free_info+0x2a/0x40 > ____kasan_slab_free+0x169/0x1d0 > slab_free_freelist_hook+0xd2/0x190 > __kmem_cache_free+0x1a1/0x2f0 > skb_release_data+0x449/0x600 > consume_skb+0x9f/0x1c0 > veth_xdp_rcv_skb+0x89c/0x1ba0 [veth] > veth_xdp_rcv+0x304/0xa20 [veth] > veth_poll+0x139/0x571 [veth] > __napi_poll+0xa1/0x440 > napi_threaded_poll+0x3d1/0x460 > kthread+0x2a2/0x340 > ret_from_fork+0x22/0x30 > > The buggy address belongs to the object at ffff888976250000 > which belongs to the cache kmalloc-2k of size 2048 > The buggy address is located 340 bytes inside of > 2048-byte region [ffff888976250000, ffff888976250800) > > The buggy address belongs to the physical page: > page:00000000ae18262a refcount:2 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x976250 > head:00000000ae18262a order:3 compound_mapcount:0 compound_pincount:0 > flags: 0x2ffff800010200(slab|head|node=0|zone=2|lastcpupid=0x1ffff) > raw: 002ffff800010200 0000000000000000 dead000000000122 ffff88810004cf00 > raw: 0000000000000000 0000000080080008 00000002ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff888976250000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888976250080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ffff888976250100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff888976250180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888976250200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > Fixes: 718a18a0c8a6 ("veth: Rework veth_xdp_rcv_skb in order to accept non-linear skb") > Signed-off-by: Shawn Bohrer Acked-by: Toshiaki Makita