From: Lin Ma <linma@zju.edu.cn>
To: jk@codeconstruct.com.au, matt@codeconstruct.com.au,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Lin Ma <linma@zju.edu.cn>
Subject: [PATCH net-next v1] net: mctp: use deprecated parser in mctp_set_link_af
Date: Thu, 28 Dec 2023 15:02:58 +0800 [thread overview]
Message-ID: <20231228070258.3052422-1-linma@zju.edu.cn> (raw)
In mctp set_link_af implementation `mctp_set_link_af`, it uses strict
parser nla_parse_nested to parse the nested attribute. This is fine in
most cases but not here, as the rtnetlink uses *bad magic* in setlink
code, see code snippet in function `do_setlink`.
nla_for_each_nested(af, tb[IFLA_AF_SPEC], rem) {
const struct rtnl_af_ops *af_ops;
BUG_ON(!(af_ops = rtnl_af_lookup(nla_type(af)))); <= (1)
err = af_ops->set_link_af(dev, af, extack); <= (2)
That is, in line (1), the attribute type of af will used to look up the
af_ops, and for MCTP case will use AF_MCTP here to get mctp_af_ops.
Therefore, the attribute with type AF_MCTP will never survive in the
check within the nla_parse_nested.
if (!(nla->nla_type & NLA_F_NESTED)) { <= nla_type is AF_MCTP
NL_SET_ERR_MSG_ATTR(extack, nla, "NLA_F_NESTED is missing");
return -EINVAL; <= always invalid
}
For other set_link_af users IPV4 and IPV6 both make a trick here by
using nla_parse_nested_deprecated, which will check the NLA_F_NESTED
then able to use this type field as family value. This patch simply port
the MCTP code also to deprecated parser to make it work.
Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
net/mctp/device.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mctp/device.c b/net/mctp/device.c
index acb97b257428..226c8e3ed85f 100644
--- a/net/mctp/device.c
+++ b/net/mctp/device.c
@@ -400,8 +400,8 @@ static int mctp_set_link_af(struct net_device *dev, const struct nlattr *attr,
struct mctp_dev *mdev;
int rc;
- rc = nla_parse_nested(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy,
- NULL);
+ rc = nla_parse_nested_deprecated(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy,
+ NULL);
if (rc)
return rc;
--
2.17.1
next reply other threads:[~2023-12-28 7:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-28 7:02 Lin Ma [this message]
2024-01-04 1:47 ` [PATCH net-next v1] net: mctp: use deprecated parser in mctp_set_link_af Jakub Kicinski
2024-01-04 6:32 ` Lin Ma
2024-01-04 6:43 ` Jeremy Kerr
2024-01-04 7:04 ` Lin Ma
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