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=-10.1 required=3.0 tests=BAYES_00,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 E4C1DC433E4 for ; Wed, 22 Jul 2020 20:42:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4B8322B3F for ; Wed, 22 Jul 2020 20:42:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="khTCCzW3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732859AbgGVUmh (ORCPT ); Wed, 22 Jul 2020 16:42:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726447AbgGVUmg (ORCPT ); Wed, 22 Jul 2020 16:42:36 -0400 Received: from mail-qv1-xf41.google.com (mail-qv1-xf41.google.com [IPv6:2607:f8b0:4864:20::f41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22FA6C0619DC; Wed, 22 Jul 2020 13:42:36 -0700 (PDT) Received: by mail-qv1-xf41.google.com with SMTP id o2so1648269qvk.6; Wed, 22 Jul 2020 13:42:36 -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=7nZNWjLqJ0D5sOjFQbHfG87wkEolo85RPk9Z6kp/ytc=; b=khTCCzW3E6Dk5KskWoX50Mju/0CtFCcalJxJWF9H1r60i0v8EtvUN5HsHgwez0hBaz yCFH9uglcgYgZ0wWnc5I6xk+uJj1JHQ5U7Zg8kT6wjVAf4pD/oTh7a2Gv3TfknsUsDjM Bczvt71B/uSq3yxvGlRjf1JoaZz6BjymEyjOJAPqk+6T+jEiOvZMJywJglwug9AWTxgE LG2y2P9FkHZ6flyxYQvqlRrmZGJTwODE8NPlYxKXvhu6YVwBKRj7rivlR5azwBNFFMVo fhMRNOA43jnKUGzMCj8PJuTpdU++IRzuMgm23vPs7PifTVmSBrfL+vCioHsL9SDRbTKA ybYw== 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=7nZNWjLqJ0D5sOjFQbHfG87wkEolo85RPk9Z6kp/ytc=; b=j14iyEI7S4Hl/IQDOc08UvFCLtSMt7xp29fxFth9wdcN8XHLfDXymRWq0J6WjM2Aos E1W28Awz23kztIbqzDsZkYXhmcd1l5xo1/IbgCpsVRwsQqisOjT2s5H1OFONpfOjZIGJ F7QmPbbqg65HkXvid6plsJ6b3mb4XTRR7PpNfq2pOTQ4nqiJ9s99tIUvSoXloFB6Jdtp s8P8siLlt+0Hp2v94ukUk6kQPUvYeD/1LtEKQLzNRCWgHZ9l8y2u+cIJ6tIjDcnSnxLF weKwiuipgbd04A7z63t+PZd1nGTqperQRxuttJDSyrOVRjTJfaMiEwFH03XYkG/+gSep ZFhA== X-Gm-Message-State: AOAM530icOQJPCUzUlhl1MpylMRRvVDVtGSBtK9JOMXA76XjS2sK/iEo sUOZtIncLUmhA5mTKhsmVQBv2vBK X-Google-Smtp-Source: ABdhPJzq2amLTw+BDxUKKCEVqbE2WSYz5u5t4BdzTKsMsXoW8MI/Qg2BDubtp40nFT4gcfbbpN5Pug== X-Received: by 2002:ad4:4b6d:: with SMTP id m13mr1830201qvx.33.1595450555197; Wed, 22 Jul 2020 13:42:35 -0700 (PDT) Received: from localhost.localdomain ([2001:1284:f016:a4f2:f184:dd41:1f10:d998]) by smtp.gmail.com with ESMTPSA id s190sm783587qkh.116.2020.07.22.13.42.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2020 13:42:34 -0700 (PDT) Received: by localhost.localdomain (Postfix, from userid 1000) id F1909C18B3; Wed, 22 Jul 2020 17:42:31 -0300 (-03) Date: Wed, 22 Jul 2020 17:42:31 -0300 From: Marcelo Ricardo Leitner To: netdev@vger.kernel.org Cc: Neil Horman , Christoph Hellwig , linux-sctp@vger.kernel.org Subject: Re: [PATCH net-next] sctp: fix slab-out-of-bounds in SCTP_DELAYED_SACK processing Message-ID: <20200722204231.GA3398@localhost.localdomain> References: <5955bc857c93d4bb64731ef7a9e90cb0094a8989.1595450200.git.marcelo.leitner@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5955bc857c93d4bb64731ef7a9e90cb0094a8989.1595450200.git.marcelo.leitner@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Cc'ing linux-sctp@vger.kernel.org. On Wed, Jul 22, 2020 at 05:38:58PM -0300, Marcelo Ricardo Leitner wrote: > This sockopt accepts two kinds of parameters, using struct > sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't > notice an implicit cast from the smaller (latter) struct to the bigger > one (former) when copying the data from the user space, which now leads > to an attempt to write beyond the buffer (because it assumes the storing > buffer is bigger than the parameter itself). > > Fix it by giving it a special buffer if the smaller struct is used by > the application. > > Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack") > Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com > Signed-off-by: Marcelo Ricardo Leitner > --- > net/sctp/socket.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index 9a767f35971865f46b39131fc8d96d8c3c2aa1a8..b71c36af7687247b4fc9e160219b76f5c41b2fe2 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -2756,6 +2756,7 @@ static int sctp_setsockopt_delayed_ack(struct sock *sk, > { > struct sctp_sock *sp = sctp_sk(sk); > struct sctp_association *asoc; > + struct sctp_sack_info _params; > > if (optlen == sizeof(struct sctp_sack_info)) { > if (params->sack_delay == 0 && params->sack_freq == 0) > @@ -2767,7 +2768,9 @@ static int sctp_setsockopt_delayed_ack(struct sock *sk, > "Use struct sctp_sack_info instead\n", > current->comm, task_pid_nr(current)); > > - if (params->sack_delay == 0) > + memcpy(&_params, params, sizeof(struct sctp_assoc_value)); > + params = &_params; > + if (((struct sctp_assoc_value *)params)->assoc_value == 0) > params->sack_freq = 1; > else > params->sack_freq = 0; > -- > 2.25.4 >