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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 DF9C6C4338F for ; Mon, 2 Aug 2021 16:34:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8C946100A for ; Mon, 2 Aug 2021 16:34:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233129AbhHBQeU (ORCPT ); Mon, 2 Aug 2021 12:34:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:45242 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233075AbhHBQeS (ORCPT ); Mon, 2 Aug 2021 12:34:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8EBB061029; Mon, 2 Aug 2021 16:34:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627922048; bh=LHx+2cUrgzNK38RC/ClXs+9ejBYjaoNRq1R6TOt9Uic=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Yhw/i4mo08T1qRcHl63LZmGXS7+q0ezK3J6xOZvHopRqx5G2QE8ekLpAMrhR83cBD gPB5ZTNSfQWTK07COdADIq2Pyojtxr8iFtuZUDPPX7DH8ws2a3XHLSCii6gsal/8kG ztoqJU3w8n1LAP7DhI5kZtHPXRvSiP3/6FUOS0UCLA5pl+GKofDtVWJcXpi7p4p0YV FKgKViSDlGgKHMMyFGFh9ig812e5DsdXpoAgDr4hdzoCjdIhRsmHxZ2nu/hev5XKcd +8qTzk2VoZtlhmcKN5XNgyNe2hXxJ7G5vqDy0Dt9tiepBnK+9vrSxCR+LfBigliZ6n 36X4zkA5/ksVg== Date: Mon, 2 Aug 2021 19:34:02 +0300 From: Leon Romanovsky To: Haris Iqbal Cc: Jack Wang , RDMA mailing list , Bart Van Assche , Doug Ledford , Jason Gunthorpe , Gioh Kim Subject: Re: [PATCH for-next 02/10] RDMA/rtrs-srv: Prevent sysfs error with path name "ctl" Message-ID: References: <20210730131832.118865-1-jinpu.wang@ionos.com> <20210730131832.118865-3-jinpu.wang@ionos.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Mon, Aug 02, 2021 at 04:24:39PM +0200, Haris Iqbal wrote: > On Mon, Aug 2, 2021 at 8:47 AM Leon Romanovsky wrote: > > > > On Fri, Jul 30, 2021 at 03:18:24PM +0200, Jack Wang wrote: > > > From: Gioh Kim > > > > > > If the client tries to create a path with name "ctl", > > > the server tries to creates /sys/devices/virtual/rtrs-server/ctl/. > > > Then server generated below error because there is already ctl directory > > > which manages some setup of the server. > > > > > > sysfs: cannot create duplicate filename '/devices/virtual/rtrs-server/ctl' > > > Workqueue: ib-comp-wq ib_cq_poll_work [ib_core] > > > Call Trace: > > > dump_stack+0x50/0x63 > > > sysfs_warn_dup.cold+0x17/0x24 > > > sysfs_create_dir_ns+0xb6/0xd0 > > > kobject_add_internal+0xa6/0x2a0 > > > kobject_add+0x7e/0xb0 > > > ? _cond_resched+0x15/0x30 > > > device_add+0x121/0x640 > > > rtrs_srv_create_sess_files+0x18f/0x1f0 [rtrs_server] > > > ? __alloc_pages_nodemask+0x16c/0x2b0 > > > ? kmalloc_order+0x7c/0x90 > > > ? kmalloc_order_trace+0x1d/0xa0 > > > ? rtrs_iu_alloc+0x17e/0x1bf [rtrs_core] > > > rtrs_srv_info_req_done+0x417/0x5b0 [rtrs_server] > > > ? __switch_to_asm+0x40/0x70 > > > __ib_process_cq+0x76/0xd0 [ib_core] > > > ib_cq_poll_work+0x26/0x80 [ib_core] > > > process_one_work+0x1df/0x3a0 > > > worker_thread+0x4a/0x3c0 > > > kthread+0xfb/0x130 > > > ? process_one_work+0x3a0/0x3a0 > > > ? kthread_park+0x90/0x90 > > > ret_from_fork+0x1f/0x40 > > > kobject_add_internal failed for ctl with -EEXIST, don't try to register things with the same name in the same directory. > > > rtrs_server L178: device_add(): -17 > > > > > > This patch checks the path name and disconnect on server to prevent > > > the kernel error. > > > > > > Signed-off-by: Gioh Kim > > > Signed-off-by: Jack Wang > > > --- > > > drivers/infiniband/ulp/rtrs/rtrs-srv.c | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > index cd9a4ccf4c28..b814a6052cf1 100644 > > > --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > > @@ -758,6 +758,14 @@ static bool exist_sessname(struct rtrs_srv_ctx *ctx, > > > struct rtrs_srv_sess *sess; > > > bool found = false; > > > > > > + /* > > > + * Session name "ct" is not allowed because > > > + * /sys/devices/virtual/rtrs-server/ctl already exists > > > + * for setup management. > > > + */ > > > + if (!strcmp(sessname, "ctl")) > > > + return true; > > > > Why does it have special treatment? > > rtrs-server creates a folder named ctl when the module is modprob'ed. > When a session is established, a folder of the session name is created > at the same location, which would hold sysfs entries such as > clt_hostname, path details, queue_depth, etc. > > Due to this conflict of names, creation of session with that name is > not possible. So this gracefully fails the connection establishment > instead of a stack trace. > > > And what will happen if user supplies "." or ".."? > > Weirdly enough, this succeeds. I tried, and the session creation > succeeds, and there is a hidden entry in the rtrs-server folder, but > it cannot be accessed through bash. All special symbols must be disallowed and filtered on the server side. > > > Does rtrs receive this session name from the other side in the network? > > Yes. This string is entered by the user while creating the session. It sounds scary > > > > > Thanks