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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 49E6EC282DD for ; Thu, 9 Jan 2020 20:09:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F5682073A for ; Thu, 9 Jan 2020 20:09:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578600552; bh=Big29PueexW7yE0BmPEfwB428xl5NVP9nUpTEaSYXmI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=juY9s4Z1gP5LwgfQ9kciOW3JkqVmZFTfyxCLL6lKbpQsdkXlJM1lMMJyjtWOUFrkG aQDplpPUlzasQTXzNk8rRio5lX7lyJZTINUjtJyqRmQeQtvMRLvPCVs4hPLklWIgsZ +V15QF7IDmiaHQUdG++rECJW1YHlut6/5ytD3l5E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729031AbgAIUJL (ORCPT ); Thu, 9 Jan 2020 15:09:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:48418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728814AbgAIUJL (ORCPT ); Thu, 9 Jan 2020 15:09:11 -0500 Received: from mail-qk1-f169.google.com (mail-qk1-f169.google.com [209.85.222.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AF00D20838; Thu, 9 Jan 2020 20:09:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578600550; bh=Big29PueexW7yE0BmPEfwB428xl5NVP9nUpTEaSYXmI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=XZU+QzBYRCJJff3UULt68MW0T2xjrVqP0eW8OuMk1sgqUN1UKZnHRxlusbYtVKrnc UGYclMWcq1QOXVlCNgzJFVpZCXLzADUV8xGbocH6P8ewQkHykz0H0lyRxGlYI4+WXn oEFJX+IVPc/nHf3A323NrPGGbHQPeTLbnRMmDfRQ= Received: by mail-qk1-f169.google.com with SMTP id t129so7227002qke.10; Thu, 09 Jan 2020 12:09:10 -0800 (PST) X-Gm-Message-State: APjAAAWEvs5AFpVinHe1UBXpnAGvVaYuICQMzp+CBsewjc8YU+VgHFoD i+mjVYzMB0St9iRdVSjmpfwdK+nSxJxkMxXmeeA= X-Google-Smtp-Source: APXvYqzVzRDsw2JT5BjOE4qWDaz2TxUmCrXlk+wS2W/VRQVdc+EYltHHjZDPxG2Vl+RYSPZVxxNLz44n5t/pfTUnk3o= X-Received: by 2002:a05:620a:1324:: with SMTP id p4mr11508648qkj.497.1578600549816; Thu, 09 Jan 2020 12:09:09 -0800 (PST) MIME-Version: 1.0 References: <157851776348.1732.12600714815781177085.stgit@ubuntu3-kvm2> <157851817088.1732.14988301389495595092.stgit@ubuntu3-kvm2> In-Reply-To: <157851817088.1732.14988301389495595092.stgit@ubuntu3-kvm2> From: Song Liu Date: Thu, 9 Jan 2020 12:08:58 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [bpf PATCH 8/9] bpf: sockmap/tls, tls_push_record can not handle zero length skmsg To: John Fastabend Cc: bpf , Networking , Alexei Starovoitov , Daniel Borkmann Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Jan 8, 2020 at 1:17 PM John Fastabend wrote: > > When passed a zero length skmsg tls_push_record() causes a NULL ptr > deref. To resolve for fixes do a simple length check at start of > routine. Could you please include the stack dump for the NULL deref? Thanks, Song > > To create this case a user can create a BPF program to pop all the > data off the message then return SK_PASS. Its not a very practical > or useful thing to do so we mark it unlikely. > > Fixes: d3b18ad31f93d ("tls: add bpf support to sk_msg handling") > Signed-off-by: John Fastabend > --- > net/tls/tls_sw.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c > index 21c7725d17ca..0326e916ab01 100644 > --- a/net/tls/tls_sw.c > +++ b/net/tls/tls_sw.c > @@ -680,6 +680,9 @@ static int tls_push_record(struct sock *sk, int flags, > msg_pl = &rec->msg_plaintext; > msg_en = &rec->msg_encrypted; > > + if (unlikely(!msg_pl->sg.size)) > + return 0; > + > split_point = msg_pl->apply_bytes; > split = split_point && split_point < msg_pl->sg.size; > if (unlikely((!split && >