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From: Leon Romanovsky <leon@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Lin Ma <linma@zju.edu.cn>,
	davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
	fw@strlen.de, yang.lee@linux.alibaba.com, jgg@ziepe.ca,
	markzhang@nvidia.com, phaddad@nvidia.com, yuancan@huawei.com,
	ohartoov@nvidia.com, chenzhongjin@huawei.com, aharonl@nvidia.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-rdma@vger.kernel.org
Subject: Re: [PATCH net v1 1/2] netlink: let len field used to parse type-not-care nested attrs
Date: Tue, 1 Aug 2023 11:11:17 +0300	[thread overview]
Message-ID: <20230801081117.GA53714@unreal> (raw)
In-Reply-To: <20230731120326.6bdd5bf9@kernel.org>

On Mon, Jul 31, 2023 at 12:03:26PM -0700, Jakub Kicinski wrote:
> On Mon, 31 Jul 2023 20:12:47 +0800 Lin Ma wrote:
> > In short, the very direct idea to fix such lengh-check-forgotten bug is
> > add nla_len() checks like
> > 
> >   if (nla_len(nla) < SOME_LEN)
> >     return -EINVAL;
> > 
> > However, this is tedious and just like Leon said: add another layer of
> > cabal knowledge. The better solution should leverage the nla_policy and
> > discard nlattr whose length is invalid when doing parsing. That is, we
> > should defined a nested_policy for the X above like
> 
> Hard no. Putting array index into attr type is an advanced case and the
> parsing code has to be able to deal with low level netlink details.

Jakub,

IMHO, you are lowering too much the separation line between simple vs.
advanced use cases. 

I had no idea that my use-case of passing nested netlink array is counted
as advanced usage.

Thanks

  parent reply	other threads:[~2023-08-01  8:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-31 12:12 [PATCH net v1 1/2] netlink: let len field used to parse type-not-care nested attrs Lin Ma
2023-07-31 19:03 ` Jakub Kicinski
2023-08-01  2:00   ` Lin Ma
2023-08-01  2:31     ` Jakub Kicinski
2023-08-01  2:40       ` Lin Ma
2023-08-01  8:11   ` Leon Romanovsky [this message]
2023-08-01 17:57     ` Jakub Kicinski
2023-08-01 19:49       ` Leon Romanovsky
2023-08-02  0:26       ` Lin Ma
2023-08-02  0:53         ` Jakub Kicinski

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