From: Florian Westphal <fw@strlen.de>
To: Quan Tian <tianquan23@gmail.com>
Cc: netfilter-devel@vger.kernel.org, pablo@netfilter.org,
kadlec@netfilter.org, fw@strlen.de
Subject: Re: [PATCH v3 nf-next 1/2] netfilter: nf_tables: use struct nlattr * to store userdata for nft_table
Date: Tue, 12 Mar 2024 15:05:35 +0100 [thread overview]
Message-ID: <20240312140535.GC1529@breakpoint.cc> (raw)
In-Reply-To: <20240311141454.31537-1-tianquan23@gmail.com>
Quan Tian <tianquan23@gmail.com> wrote:
> u32 nlpid;
> char *name;
> - u16 udlen;
> - u8 *udata;
> + struct nlattr *udata;
I missed this detail. As Pablo pointed out this pointer
now needs a __rcu annotation.
And this needs something like:
struct nlattr *udata = rcu_dereference(table->udata);
if (udata) {
if (nla_put(skb, NFTA_TABLE_USERDATA, nla_len(udata), nla_data(udata)))
> + if (nla_put(skb, NFTA_TABLE_USERDATA, nla_len(table->udata),
> + nla_data(table->udata)))
... because this version can observe different table->udata for
nla_len() and nla_data() calls if the swap() has the "right" / "wrong"
timing.
next prev parent reply other threads:[~2024-03-12 14:05 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-11 14:14 [PATCH v3 nf-next 1/2] netfilter: nf_tables: use struct nlattr * to store userdata for nft_table Quan Tian
2024-03-11 14:14 ` [PATCH v3 nf-next 2/2] netfilter: nf_tables: support updating " Quan Tian
2024-03-12 12:27 ` Florian Westphal
2024-03-12 12:49 ` Pablo Neira Ayuso
2024-03-12 13:01 ` Florian Westphal
2024-03-12 14:26 ` Quan Tian
2024-03-12 14:33 ` Florian Westphal
2024-03-12 22:23 ` Pablo Neira Ayuso
2024-03-13 1:35 ` Quan Tian
2024-03-13 9:40 ` Pablo Neira Ayuso
2024-03-13 17:08 ` Quan Tian
2024-03-12 14:36 ` Pablo Neira Ayuso
2024-03-12 13:49 ` Pablo Neira Ayuso
2024-03-12 14:02 ` Florian Westphal
2024-03-12 14:10 ` Florian Westphal
2024-03-12 14:30 ` Quan Tian
2024-03-12 14:05 ` Florian Westphal [this message]
2024-03-12 14:17 ` [PATCH v3 nf-next 1/2] netfilter: nf_tables: use struct nlattr * to store " Pablo Neira Ayuso
2024-03-12 14:34 ` Florian Westphal
2024-03-12 15:03 ` Quan Tian
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