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=-7.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 9BAAEC11F66 for ; Tue, 13 Jul 2021 13:47:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81FBA61249 for ; Tue, 13 Jul 2021 13:47:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236468AbhGMNuN (ORCPT ); Tue, 13 Jul 2021 09:50:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236222AbhGMNuN (ORCPT ); Tue, 13 Jul 2021 09:50:13 -0400 Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3972FC0613DD; Tue, 13 Jul 2021 06:47:23 -0700 (PDT) Received: by mail-wr1-x42b.google.com with SMTP id p8so30550186wrr.1; Tue, 13 Jul 2021 06:47:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=X/AEnKgR35dch3/Dd4uftg3ppYbt85cCwHqG8mB8H40=; b=hHPV0jO0A53LsFdk1uIC2UDPRjwsgp6Khb9VjaAoaF31e/tfTM/VZeelFGvz4A1LhQ VqIsT7exIXTKWb635pIeS2si1JfsMbllUg1pTpFXsgyiobOVnFTfPr6Zdqub1qB0GL2p Z4K9vbagjhnMaI+y9VE2nbP/7Na7sf/NnDzveuSHKPfogbo11SPevbH3ZJauTo7nso/H 9gq4gSxmaXQ6I83ipChNMc3ow8UhHjeN1dtMvapBqI6quoHXubYjckkF0g8vlcQAa6OM zLrInzQEl/8ObWfTF2c4kPlyViBRTBLGzryI2xPP371Yz51cRxZIaVGkgTKH1JLbyv/w huFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=X/AEnKgR35dch3/Dd4uftg3ppYbt85cCwHqG8mB8H40=; b=mEi5TdzyNO4XNJ44hfSfEnDO+B+32UYSmZ3lJkt9tJZ+yeFwevSRz4AIZ3NhbXg/8T FdjxHIn3Pnw1xpgVvKiWLBq2nulB7XnJHlvo9KBhxUg46UOOxCB8sgX9N2KB3jxf5lxw Oc75nj1SKDgzKvpvV0aXAVtZEsCcL9LhCpcqqOGWHKW2DDolIJxxA6f3+Jf+ClEt2jGr wkM0OvRUIUUBKKLSANv8Nh6/FXF7v8sE1G9Jj/YB6++7czQjLdb9rqfpdfa7YWjpIXyd mVg5BFDc7fUXdi6N7Ym7e5QXgUQoPoei/45AVh3+QVAAmdcnvIYARBam8/qGyZ6keFES daqA== X-Gm-Message-State: AOAM531kOCCaa0aE61+Wt1bE8wCJ7Z14y9p82EPceqMPVTF8gE2ooz6l zsZEsbo5HcanCgMEgLXOW5us3LMAceheG+EUfLg= X-Google-Smtp-Source: ABdhPJxz/AMLqAjw+OLCeNgQzB+GRtUscV/kpXH6OPXF7N3eeXF6ZvPSvKnOblE9jj+X0nhUUX+w/Dq7KnNhXY8VWHQ= X-Received: by 2002:a5d:530b:: with SMTP id e11mr2420650wrv.65.1626184041894; Tue, 13 Jul 2021 06:47:21 -0700 (PDT) MIME-Version: 1.0 References: <20210713054019.409273-1-mudongliangabcd@gmail.com> In-Reply-To: <20210713054019.409273-1-mudongliangabcd@gmail.com> From: Alexander Aring Date: Tue, 13 Jul 2021 09:47:10 -0400 Message-ID: Subject: Re: [PATCH] ieee802154: hwsim: fix memory leak in __pskb_copy_fclone To: Dongliang Mu Cc: Stefan Schmidt , "David S. Miller" , Jakub Kicinski , Alexander Aring , linux-wpan - ML , "open list:NETWORKING [GENERAL]" , kernel list Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-wpan@vger.kernel.org Hi, On Tue, 13 Jul 2021 at 01:40, Dongliang Mu wrote: > > hwsim_hw_xmit fails to deallocate the newskb copied by pskb_copy. Fix > this by adding kfree_skb after ieee802154_rx_irqsafe. > > [] __alloc_skb+0x22b/0x250 net/core/skbuff.c:414 > [] __pskb_copy_fclone+0x75/0x360 net/core/skbuff.c:1609 > [] __pskb_copy include/linux/skbuff.h:1176 [inline] > [] pskb_copy include/linux/skbuff.h:3207 [inline] > [] hwsim_hw_xmit+0xd3/0x140 drivers/net/ieee802154/mac802154_hwsim.c:132 > [] drv_xmit_async net/mac802154/driver-ops.h:16 [inline] > [] ieee802154_tx+0xc7/0x190 net/mac802154/tx.c:83 > [] ieee802154_subif_start_xmit+0x58/0x70 net/mac802154/tx.c:132 > [] __netdev_start_xmit include/linux/netdevice.h:4944 [inline] > [] netdev_start_xmit include/linux/netdevice.h:4958 [inline] > [] xmit_one net/core/dev.c:3658 [inline] > [] dev_hard_start_xmit+0xe2/0x330 net/core/dev.c:3674 > [] sch_direct_xmit+0xf8/0x520 net/sched/sch_generic.c:342 > [] __dev_xmit_skb net/core/dev.c:3874 [inline] > [] __dev_queue_xmit+0xa3b/0x1360 net/core/dev.c:4241 > [] dgram_sendmsg+0x437/0x570 net/ieee802154/socket.c:682 > [] sock_sendmsg_nosec net/socket.c:702 [inline] > [] sock_sendmsg+0x56/0x80 net/socket.c:722 > > Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb") > Signed-off-by: Dongliang Mu sorry, I don't get the fix. Is this a memory leak? I remember there was something reported by syzkaller [0] but I wasn't able yet to get into it. Is it what you referring to? __pskb_copy_fclone() shows "The returned buffer has a reference count of 1" and ieee802154_rx_irqsafe() will queue the skb for a tasklet. With your patch it will be immediately freed and a use after free will occur. I believe there is something wrong in the error path of 802.15.4 frame parsing and that's why we sometimes have a leaks there. I need to test this patch, but I don't get how this patch is supposed to fix the issue. - Alex [0] https://groups.google.com/g/syzkaller-bugs/c/EoIvZbk3Zfo/m/AlKUiErlAwAJ