From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1094A258ED5; Fri, 3 Apr 2026 08:52:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775206352; cv=none; b=uvT74cnBs5gvXPln500fIFCRz5QmlFZ5ods7uqiyt4NwCkHcvER7weciNYZhg6zWadrNStYM3y0c0oB4F7o9ftxmfG2MHoruRjmaaGKzDD5s9h7xwfiHGfUOLlSqfZoFEBiApaoAQeiFsllNq+I/Vi45J4wf2wGYJRLWVErNnKw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775206352; c=relaxed/simple; bh=IDva14KQXbd5tPuTsNnsc2rZpb5o1Jahg81DfTbN2Sg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cAtYhyEUCAbpxuVbzBK6zZStT1QUmXBn5BbzkEob0g4dHCURc9k9V2P/xWiz3JQzsx3gjee5Cx5uIZgv8uzkvmOPcDbsOW+EKjvVmvyM4uns3BMTooKTk5A4T+HGQr2yfCT149Np1gNsFaFtqSGJq4hCJz8tb2jStYWdbZXIPsA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=sL5N3/g7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="sL5N3/g7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55D4BC4CEF7; Fri, 3 Apr 2026 08:52:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775206351; bh=IDva14KQXbd5tPuTsNnsc2rZpb5o1Jahg81DfTbN2Sg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sL5N3/g7zGn6NwiL6MnkV2jdZodbynG59W3foy/hSC4tVB1K7QGpwzWxyurlg09G4 r9zPKPqSjGS9OiYreZrkeho0B6Lxu6v8tH0v8m/QGqqQJsTV1JeUOwGMf0eUh5V2n8 FUSbUDxClKE4Pd2tzY0voSD+ySiNXR7wOwloCxXZ4df9rvkrK2t0UNGOAMwiBhCm2P mp58rwUOJBATACSKHqnOc23jfU13ncBQxvokjhQRknzs+udNenoAXtMncIZX+OWK6q lu1VeR8y0cgb39OsHZ0mJp777nswVrxopbBW04xau48TMBWK97YEuMHGwwwz5V1I8u lq7ZYbzklZYoQ== Date: Fri, 3 Apr 2026 09:52:26 +0100 From: Simon Horman To: Manivannan Sadhasivam Cc: Manivannan Sadhasivam , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, andersson@kernel.org, yimingqian591@gmail.com, chris.lew@oss.qualcomm.com, stable@vger.kernel.org Subject: Re: [PATCH 1/2] net: qrtr: ns: Limit the maximum server registration per node Message-ID: <20260403085226.GA26061@horms.kernel.org> References: <20260325104415.104972-1-manivannan.sadhasivam@oss.qualcomm.com> <20260325104415.104972-2-manivannan.sadhasivam@oss.qualcomm.com> <20260327095832.GC111839@horms.kernel.org> <20260403083009.GA11973@horms.kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260403083009.GA11973@horms.kernel.org> On Fri, Apr 03, 2026 at 09:30:09AM +0100, Simon Horman wrote: > On Fri, Mar 27, 2026 at 03:40:01PM +0530, Manivannan Sadhasivam wrote: > > On Fri, Mar 27, 2026 at 09:58:32AM +0000, Simon Horman wrote: > > > On Wed, Mar 25, 2026 at 04:14:14PM +0530, Manivannan Sadhasivam wrote: > > > > Current code does no bound checking on the number of servers added per > > > > node. A malicious client can flood NEW_SERVER messages and exhaust memory. > > > > > > > > Fix this issue by limiting the maximum number of server registrations to > > > > 256 per node. If the NEW_SERVER message is received for an old port, then > > > > don't restrict it as it will get replaced. > > > > > > > > Note that the limit of 256 is chosen based on the current platform > > > > requirements. If requirement changes in the future, this limit can be > > > > increased. > > > > > > > > Cc: stable@vger.kernel.org > > > > Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace") > > > > Reported-by: Yiming Qian > > > > Signed-off-by: Manivannan Sadhasivam > > > > > > Reviewed-by: Simon Horman > > > > > > > --- > > > > net/qrtr/ns.c | 24 ++++++++++++++++++++---- > > > > 1 file changed, 20 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c > > > > index 3203b2220860..fb4e8a2d370d 100644 > > > > --- a/net/qrtr/ns.c > > > > +++ b/net/qrtr/ns.c > > > > @@ -67,8 +67,14 @@ struct qrtr_server { > > > > struct qrtr_node { > > > > unsigned int id; > > > > struct xarray servers; > > > > + u32 server_count; > > > > }; > > > > > > > > +/* Max server limit is chosen based on the current platform requirements. If the > > > > + * requirement changes in the future, this value can be increased. > > > > + */ > > > > +#define QRTR_NS_MAX_SERVERS 256 > > > > + > > > > static struct qrtr_node *node_get(unsigned int node_id) > > > > { > > > > struct qrtr_node *node; > > > > @@ -229,6 +235,17 @@ static struct qrtr_server *server_add(unsigned int service, > > > > if (!service || !port) > > > > return NULL; > > > > > > > > + node = node_get(node_id); > > > > + if (!node) > > > > + return NULL; > > > > > > This is not new behaviour added by patch, but If I understand things > > > correctly, node_get will allocate a new node if one doesn't already exist > > > for the node_id. > > > > > > > Yes! > > > > > I am wondering if any bounds are placed on the number of nodes that can be > > > created. And, if not, is this a point of concern from a memory exhaustion > > > perspective? > > > > > > > That's true. I plan to send a followup for that. This series just limits the > > scope in addressing the reported issue. > > Thanks, sounds good to me. > > For this patch, feel free to add: > > Reviewed-by: Simon Horman Sorry, I now see Jakub's comment on this. So I'll review the revised series, addressing the concern above, when it becomes available. Feel free to include my Reviewed-by tags on patches that don't change in a material way.