[PATCH net v2] net/sched: cls_api: add missing validation of netlink attributes

[PATCH net v2] net/sched: cls_api: add missing validation of netlink attributes

[Davide Caratti]

Similarly to what has been done in 8b4c3cdd9dd8 ("net: sched: Add policy
validation for tc attributes"), fix classifier code to add validation of
TCA_CHAIN and TCA_KIND netlink attributes.

tested with:
 # ./tdc.py -c filter

v2: let sch_api and cls_api share nla_policy they have in common, thanks
    to David Ahern

Fixes: 5bc1701881e39 ("net: sched: introduce multichain support for filters")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 include/net/sch_generic.h |  2 ++
 net/sched/cls_api.c       | 11 ++++++-----
 net/sched/sch_api.c       |  1 +
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index a6d00093f35e..8f4335c0a6c8 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -487,6 +487,8 @@ extern struct Qdisc_ops pfifo_fast_ops;
 extern struct Qdisc_ops mq_qdisc_ops;
 extern struct Qdisc_ops noqueue_qdisc_ops;
 extern const struct Qdisc_ops *default_qdisc_ops;
+extern const struct nla_policy rtm_tca_policy[];
+
 static inline const struct Qdisc_ops *
 get_default_qdisc_ops(const struct net_device *dev, int ntx)
 {
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 0a75cb2e5e7b..5f72190bf36c 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1211,7 +1211,7 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 replay:
 	tp_created = 0;
 
-	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
+	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
 	if (err < 0)
 		return err;
 
@@ -1360,7 +1360,7 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 		return -EPERM;
 
-	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
+	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
 	if (err < 0)
 		return err;
 
@@ -1475,7 +1475,7 @@ static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 	void *fh = NULL;
 	int err;
 
-	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
+	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
 	if (err < 0)
 		return err;
 
@@ -1838,7 +1838,7 @@ static int tc_ctl_chain(struct sk_buff *skb, struct nlmsghdr *n,
 		return -EPERM;
 
 replay:
-	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL, extack);
+	err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, rtm_tca_policy, extack);
 	if (err < 0)
 		return err;
 
@@ -1949,7 +1949,8 @@ static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb)
 	if (nlmsg_len(cb->nlh) < sizeof(*tcm))
 		return skb->len;
 
-	err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, NULL);
+	err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
+			  NULL);
 	if (err)
 		return err;
 
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 85e73f48e48f..99eae8007567 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1322,6 +1322,7 @@ const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
 	[TCA_INGRESS_BLOCK]	= { .type = NLA_U32 },
 	[TCA_EGRESS_BLOCK]	= { .type = NLA_U32 },
 };
+EXPORT_SYMBOL(rtm_tca_policy);
 
 static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
 			struct netlink_ext_ack *extack)
-- 
2.17.1

Re: [PATCH net v2] net/sched: cls_api: add missing validation of netlink attributes

[Cong Wang]

On Tue, Oct 9, 2018 at 2:26 PM Davide Caratti <dcaratti@redhat.com> wrote:
> --- a/net/sched/sch_api.c
> +++ b/net/sched/sch_api.c
> @@ -1322,6 +1322,7 @@ const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
>         [TCA_INGRESS_BLOCK]     = { .type = NLA_U32 },
>         [TCA_EGRESS_BLOCK]      = { .type = NLA_U32 },
>  };
> +EXPORT_SYMBOL(rtm_tca_policy);

cls_api.c is not a module, so you don't need to export it.