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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C220FC433F5 for ; Wed, 29 Sep 2021 12:04:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D839613A7 for ; Wed, 29 Sep 2021 12:04:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245225AbhI2MGb (ORCPT ); Wed, 29 Sep 2021 08:06:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:53928 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245211AbhI2MGb (ORCPT ); Wed, 29 Sep 2021 08:06:31 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7141D61406; Wed, 29 Sep 2021 12:04:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632917090; bh=OmNdazFoMZCKQ8r4ReuRZKLs38PLrawSuhZV6i5Gql0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pFbvC0gwC5XJG2wnE8cftn0JFyJh++cnHSw5Y0bfFsBCEz1UoB7O4xQqBpHSn+oMZ a9rc1Uppa/Q4K+hjr2UlPkIBHz/eHvynhVtf9Lv6v89aNyaRZF99csS+wRzppomGMf TQRHK4ts55in7YWK3QhatMqKddMXFK0ympW9bkr5tUc0BJVwP2mkhIDJT3PYRClUam AqvAzvwuUBUI6ecs8hz2n4U5T6lOGG3TNAUFtF7JEbjaUKNwZsaFlQhWC1rn2j7bCf /ojKUxMnsuJ9m2PgAQpvBef2QT+I/XIrdVLSWaKNoCUswd4WTFaZdu++Ujjgpi+1KC djxg3Cqa6tb8A== Date: Wed, 29 Sep 2021 15:04:46 +0300 From: Leon Romanovsky To: Jack Wang Cc: Md Haris Iqbal , RDMA mailing list , Bart Van Assche , Doug Ledford , Jason Gunthorpe , Jack Wang , Gioh Kim , Aleksei Marov Subject: Re: [PATCH for-next 6/7] RDMA/rtrs: Do not allow sessname to contain special symbols / and . Message-ID: References: <20210922125333.351454-1-haris.iqbal@ionos.com> <20210922125333.351454-7-haris.iqbal@ionos.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Wed, Sep 29, 2021 at 09:00:56AM +0200, Jack Wang wrote: > Leon Romanovsky 于2021年9月28日周二 上午9:28写道： > > > > On Tue, Sep 28, 2021 at 09:08:26AM +0200, Jack Wang wrote: > > > Leon Romanovsky 于2021年9月27日周一 下午2:23写道： > > > > > > > > On Wed, Sep 22, 2021 at 02:53:32PM +0200, Md Haris Iqbal wrote: > > > > > Allowing these characters in sessname can lead to unexpected results, > > > > > particularly because / is used as a separator between files in a path, > > > > > and . points to the current directory. > > > > > > > > > > Signed-off-by: Md Haris Iqbal > > > > > Reviewed-by: Gioh Kim > > > > > Reviewed-by: Aleksei Marov > > > > > --- > > > > > drivers/infiniband/ulp/rtrs/rtrs-clt.c | 6 ++++++ > > > > > drivers/infiniband/ulp/rtrs/rtrs-srv.c | 5 +++++ > > > > > 2 files changed, 11 insertions(+) > > > > > > > > It will be safer if you check for only allowed symbols and disallow > > > > everything else. Check for: a-Z, 0-9 and "-". > > > > > > > Hi Leon, > > > > > > Thanks for your suggestions. > > > The reasons we choose to do disallow only '/' and '.': > > > 1 more flexible, most UNIX filenames allow any 8-bit set, except '/' and null. > > > > So you need to add all possible protections and checks that VFS has to allow "random" name. > It's only about sysfs here, as we use sessname to create dir in sysfs, > and I checked the code, it allows any 8-bit set, and convert '/' to > '!', see https://elixir.bootlin.com/linux/latest/source/lib/kobject.c#L299 > > > > > 2 matching for 2 characters is faster than checking all the allowed > > > symbols during session establishment. > > > > Extra CPU cycles won't make any difference here. > As we can have hundreds of sessions, in the end, it matters. Your rtrs_clt_open() function is far from being optimized for performance. It allocates memory, iterates over all paths, creates sysfs and kobject. So no, it doesn't matter here. Thanks > > Thanks > > > > > 3 we do use hostnameA@hostnameB for production usage right now, we > > > don't want to break the user space. > > > > You can add "@" into the list of accepted symbols. > > > > > > > > I hope this makes sense to you. > > > > > > Regards! > > > > > > > > > > > > > > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c > > > > > index bc8824b4ee0d..15c0077dd27e 100644 > > > > > --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c > > > > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c > > > > > @@ -2788,6 +2788,12 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops, > > > > > struct rtrs_clt *clt; > > > > > int err, i; > > > > > > > > > > + if (strchr(sessname, '/') || strchr(sessname, '.')) { > > > > > + pr_err("sessname cannot contain / and .\n"); > > > > > + err = -EINVAL; > > > > > + goto out; > > > > > + } > > > > > + > > > > > clt = alloc_clt(sessname, paths_num, port, pdu_sz, ops->priv, > > > > > ops->link_ev, > > > > > reconnect_delay_sec, > > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > > > index 078a1cbac90c..7df71f8cf149 100644 > > > > > --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > > > @@ -803,6 +803,11 @@ static int process_info_req(struct rtrs_srv_con *con, > > > > > return err; > > > > > } > > > > > > > > > > + if (strchr(msg->sessname, '/') || strchr(msg->sessname, '.')) { > > > > > + rtrs_err(s, "sessname cannot contain / and .\n"); > > > > > + return -EINVAL; > > > > > + } > > > > > + > > > > > if (exist_sessname(sess->srv->ctx, > > > > > msg->sessname, &sess->srv->paths_uuid)) { > > > > > rtrs_err(s, "sessname is duplicated: %s\n", msg->sessname); > > > > > -- > > > > > 2.25.1 > > > > >