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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 8915CC1975A for ; Tue, 17 Mar 2020 17:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6359120724 for ; Tue, 17 Mar 2020 17:30:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bWh2drfz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbgCQRaq (ORCPT ); Tue, 17 Mar 2020 13:30:46 -0400 Received: from mail-qv1-f68.google.com ([209.85.219.68]:39442 "EHLO mail-qv1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726082AbgCQRaq (ORCPT ); Tue, 17 Mar 2020 13:30:46 -0400 Received: by mail-qv1-f68.google.com with SMTP id v38so7281530qvf.6; Tue, 17 Mar 2020 10:30:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=uMZI9G+vOGyFJSyjy5BLGE+SbevgQEUuqjy8SQ3+oEs=; b=bWh2drfzNsrrjWxTp0zb6MrVMeXTLND0nB3Z8X/MPrWKZC6ZJWYOvgc6bps+int15o +rY8bKArNwjzuLFeyrx2ILFrr7pOnSPSR16JqcNyQg6bWQAbyCAenxmW58/7dFikmCLY a1RCBsCrlO6LYmgRClI8BfYIWzrFKgS4k2QCcMVXVRyEbEPVFY2C/BO8JmHCtY5xM8HT +65qwSnPt5fUOHF6oYUkjryI4HeqIbY9mMxn7PkqifgY8FzMcy/5MjFT3pyAfeKPRxSW NU/X9g8sjTTrxBCuWC+iTaiKwlQYAqNwWxhfMKR4Looj5rrs7sT0sqy3xubCe+KcSVLK gneg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=uMZI9G+vOGyFJSyjy5BLGE+SbevgQEUuqjy8SQ3+oEs=; b=VMWWmZaLCz6dZPgnP5g/vFjgSzG83PDULC7ERAUhyG69I0StDgIPV1K1Q6QUzAa9h5 LYZ+6hU1kFgnu28yOOnJsVu5BIzJqrr1gVsnbqQxWxClZqQ1CH8k07O002ZOY8AIJYKS ju3PpbFoSecM4i89Via/Lj9pHInpvZHvuYuCSgANd7UudJRLnUA6JYKbMam45gUFjyBm wOolumsOFCtciy9Um9TYpubc8wzSO32ww9HW4ehijst6gFs7E3y3EbfC/yNjPgxazP3K cH8C+7JRjFcO5dasLdh6WqIA6+7p7sn2YiS3cpLAgbcYgYBl6rbsj7yOjVrePfs1gkDt NX5A== X-Gm-Message-State: ANhLgQ3hWk7ygPFrK0D64USGvTOrBPUKCCOPUZyzP7OS3PoNcMPmPyYM xq91M6w6oHMUn+tIiPhn2Nw= X-Google-Smtp-Source: ADFU+vsxfQXEWzA4tzIws3q/lri+BobagJ+smPhVzlUG+fAuPQFgpcO4I42vwikyOCMQj8SCBopeng== X-Received: by 2002:ad4:51c3:: with SMTP id p3mr210903qvq.97.1584466242913; Tue, 17 Mar 2020 10:30:42 -0700 (PDT) Received: from localhost.localdomain ([2001:1284:f013:bfaf:5636:cd03:74f7:34b0]) by smtp.gmail.com with ESMTPSA id c12sm2808948qtb.49.2020.03.17.10.30.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Mar 2020 10:30:42 -0700 (PDT) Received: by localhost.localdomain (Postfix, from userid 1000) id C39FBC54E2; Tue, 17 Mar 2020 14:30:39 -0300 (-03) Date: Tue, 17 Mar 2020 14:30:39 -0300 From: Marcelo Ricardo Leitner To: Qiujun Huang Cc: davem@davemloft.net, vyasevich@gmail.com, nhorman@tuxdriver.com, kuba@kernel.org, linux-sctp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, anenbupt@gmail.com Subject: Re: [PATCH v2] sctp: fix refcount bug in sctp_wfree Message-ID: <20200317173039.GA3828@localhost.localdomain> References: <20200317155536.10227-1-hqjagain@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200317155536.10227-1-hqjagain@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, On Tue, Mar 17, 2020 at 11:55:36PM +0800, Qiujun Huang wrote: > Do accounting for skb's real sk. > In some case skb->sk != asoc->base.sk: > > migrate routing sctp_check_transmitted routing > ------------ --------------- sctp_close(); lock_sock(sk2); sctp_primitive_ABORT(); sctp_do_sm(); sctp_cmd_interpreter(); sctp_cmd_process_sack(); sctp_outq_sack(); sctp_check_transmitted(); lock_sock(sk1); sctp_getsockopt_peeloff(); sctp_do_peeloff(); sctp_sock_migrate(); > lock_sock_nested(sk2); > mv the transmitted skb to > the it's local tlist How can sctp_do_sm() be called in the 2nd column so that it bypasses the locks in the left column, allowing this mv to happen? > > sctp_for_each_tx_datachunk( > sctp_clear_owner_w); > sctp_assoc_migrate(); > sctp_for_each_tx_datachunk( > sctp_set_owner_w); > > put the skb back to the > assoc lists > ---------------------------------------------------- > > The skbs which held bysctp_check_transmitted were not changed > to newsk. They were not dealt with by sctp_for_each_tx_datachunk > (sctp_clear_owner_w/sctp_set_owner_w). It would make sense but I'm missing one step earlier, I'm not seeing how the move to local list is allowed/possible in there. It really shouldn't be possible. > > It looks only trouble here so handling it in sctp_wfree is enough. > > Reported-and-tested-by: syzbot+cea71eec5d6de256d54d@syzkaller.appspotmail.com > Signed-off-by: Qiujun Huang > --- > net/sctp/socket.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index 1b56fc440606..5f5c28b30e25 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -9080,7 +9080,7 @@ static void sctp_wfree(struct sk_buff *skb) > { > struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg; > struct sctp_association *asoc = chunk->asoc; > - struct sock *sk = asoc->base.sk; > + struct sock *sk = skb->sk; > > sk_mem_uncharge(sk, skb->truesize); > sk->sk_wmem_queued -= skb->truesize + sizeof(struct sctp_chunk); > @@ -9109,7 +9109,7 @@ static void sctp_wfree(struct sk_buff *skb) > } > > sock_wfree(skb); > - sctp_wake_up_waiters(sk, asoc); > + sctp_wake_up_waiters(asoc->base.sk, asoc); > > sctp_association_put(asoc); > } > -- > 2.17.1 >