From: Lin Ma <linma@zju.edu.cn>
To: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, netdev@vger.kernel.org
Cc: Lin Ma <linma@zju.edu.cn>
Subject: [PATCH v1] net/sched: act_pedit: Add size check for TCA_PEDIT_PARMS_EX
Date: Mon, 3 Jul 2023 19:08:42 +0800 [thread overview]
Message-ID: <20230703110842.590282-1-linma@zju.edu.cn> (raw)
The attribute TCA_PEDIT_PARMS_EX is not be included in pedit_policy and
one malicious user could fake a TCA_PEDIT_PARMS_EX whose length is
smaller than the intended sizeof(struct tc_pedit). Hence, the
dereference in tcf_pedit_init() could access dirty heap data.
static int tcf_pedit_init(...)
{
// ...
pattr = tb[TCA_PEDIT_PARMS]; // TCA_PEDIT_PARMS is included
if (!pattr)
pattr = tb[TCA_PEDIT_PARMS_EX]; // but this is not
// ...
parm = nla_data(pattr);
index = parm->index; // parm is able to be smaller than 4 bytes
// and this dereference gets dirty skb_buff
// data created in netlink_sendmsg
}
This commit adds TCA_PEDIT_PARMS_EX length in pedit_policy which avoid
the above case, just like the TCA_PEDIT_PARMS.
Fixes: 71d0ed7079df ("net/act_pedit: Support using offset relative to the conventional network headers")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
net/sched/act_pedit.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index b562fc2bb5b1..1ef8fcfa9997 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -29,6 +29,7 @@ static struct tc_action_ops act_pedit_ops;
static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
[TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) },
+ [TCA_PEDIT_PARMS_EX] = { .len = sizeof(struct tc_pedit) },
[TCA_PEDIT_KEYS_EX] = { .type = NLA_NESTED },
};
--
2.17.1
next reply other threads:[~2023-07-03 11:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 11:08 Lin Ma [this message]
2023-07-03 14:21 ` [PATCH v1] net/sched: act_pedit: Add size check for TCA_PEDIT_PARMS_EX Pedro Tammela
2023-07-04 12:50 ` patchwork-bot+netdevbpf
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