[PATCH net] 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"), add validation for TCA_CHAIN and TCA_KIND
netlink attributes.

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

Fixes: 5bc1701881e39 ("net: sched: introduce multichain support for filters")
Signed-off-by: Davide Caratti <dcara...@redhat.com>
---
 net/sched/cls_api.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 0a75cb2e5e7b..fb1afc0e130d 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -37,6 +37,11 @@ static LIST_HEAD(tcf_proto_base);
 /* Protects list of registered TC modules. It is pure SMP lock. */
 static DEFINE_RWLOCK(cls_mod_lock);
 
+const struct nla_policy cls_tca_policy[TCA_MAX + 1] = {
+       [TCA_KIND]      = { .type = NLA_STRING },
+       [TCA_CHAIN]     = { .type = NLA_U32 },
+};
+
 /* Find classifier type by string name */
 
 static const struct tcf_proto_ops *__tcf_proto_lookup_ops(const char *kind)
@@ -1211,7 +1216,7 @@ 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, cls_tca_policy, extack);
        if (err < 0)
                return err;
 
@@ -1360,7 +1365,7 @@ 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, cls_tca_policy, extack);
        if (err < 0)
                return err;
 
@@ -1475,7 +1480,7 @@ 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, cls_tca_policy, extack);
        if (err < 0)
                return err;
 
@@ -1838,7 +1843,7 @@ 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, cls_tca_policy, extack);
        if (err < 0)
                return err;
 
@@ -1949,7 +1954,8 @@ 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, cls_tca_policy,
+                         NULL);
        if (err)
                return err;
 
-- 
2.17.1