Re: [PATCH net-next v6 1/1] net sched actions: Add support for user cookies

[Jamal Hadi Salim]

On 17-01-23 07:58 AM, Simon Horman wrote:

Hi Jamal,

On Sun, Jan 22, 2017 at 03:25:50PM -0500, Jamal Hadi Salim wrote:

...

@@ -33,6 +34,8 @@ static void free_tcf(struct rcu_head *head)

        free_percpu(p->cpu_bstats);
        free_percpu(p->cpu_qstats);
+       kfree(p->act_cookie->data);

Does the above need to be protected by a check for p->act_cookie being non-NULL?

Indeed it does.

+       kfree(p->act_cookie);
        kfree(p);
 }

...

@@ -575,6 +584,33 @@ struct tc_action *tcf_action_init_1(struct net *net, 
struct nlattr *nla,
        if (err < 0)
                goto err_mod;

+       if (tb[TCA_ACT_COOKIE]) {
+               int cklen = nla_len(tb[TCA_ACT_COOKIE]);
+
+               if (cklen > TC_COOKIE_MAX_SIZE) {
+                       err = -EINVAL;
+                       tcf_hash_release(a, bind);
+                       goto err_mod;
+               }
+
+               a->act_cookie = kzalloc(sizeof(*a->act_cookie), GFP_KERNEL);
+               if (!a->act_cookie) {
+                       err = -ENOMEM;
+                       tcf_hash_release(a, bind);
+                       goto err_mod;
+               }
+
+               a->act_cookie->data = nla_memdup(tb[TCA_ACT_COOKIE],
+                                                GFP_KERNEL);
+               if (!a->act_cookie->data) {
+                       err = -ENOMEM;
+                       kfree(a->act_cookie);
+                       tcf_hash_release(a, bind);
+                       goto err_mod;
+               }
+               a->act_cookie->len = cklen;

FWIW, the above looks correct but it also looks like the error handling
could be done less verbosely if the logic was moved to a separate function.

I will make the change.

Thanks Simon.

cheers,
jamal