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From: Lin Ma <linma@zju.edu.cn>
To: jhs@mojatatu.com,
	xiyou.wangcong@gmail.com,
	jiri@resnulli.us,
	davem@davemloft.net,
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	linux-kernel@vger.kernel.org
Cc: Lin Ma <linma@zju.edu.cn>
Subject: [PATCH net-next v2] net/sched: cls_api: complement tcf_tfilter_dump_policy
Date: Thu, 28 Dec 2023 14:43:58 +0800
Message-Id: <20231228064358.3042747-1-linma@zju.edu.cn>
Precedence: bulk

In function `tc_dump_tfilter`, the attributes array is parsed via
tcf_tfilter_dump_policy which only describes TCA_DUMP_FLAGS. However,
the NLA TCA_CHAIN is also accessed with `nla_get_u32`.

The access to TCA_CHAIN is introduced in commit 5bc1701881e3 ("net:
sched: introduce multichain support for filters") and no nla_policy is
provided for parsing at that point. Later on, tcf_tfilter_dump_policy is
introduced in commit f8ab1807a9c9 ("net: sched: introduce terse dump
flag") while still ignoring the fact that TCA_CHAIN needs a check. This
patch does that by complementing the policy to allow the access
discussed here can be safe as other cases just choose rtm_tca_policy as
the parsing policy.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
V1 -> V2: send to net-next as told by Jamal <jhs@mojatatu.com>

 net/sched/cls_api.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 1976bd163986..2b5b8eca2ee3 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -2732,6 +2732,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
 }
 
 static const struct nla_policy tcf_tfilter_dump_policy[TCA_MAX + 1] = {
+	[TCA_CHAIN]      = { .type = NLA_U32 },
 	[TCA_DUMP_FLAGS] = NLA_POLICY_BITFIELD32(TCA_DUMP_FLAGS_TERSE),
 };
 
-- 
2.17.1