Re: [syzbot] WARNING in u32_change

[Jamal Hadi Salim]

On Sun, Sep 25, 2022 at 11:38 AM Jamal Hadi Salim <jhs@xxxxxxxxxxxx> wrote:
>
> Is there a way to tell the boat "looking into it?"


I guess I have to swim across to it to get the message;->

I couldnt see the warning message  but it is obvious by inspection that
the memcpy is broken. We should add more test coverage.
This should fix it. Will send a formal patch later:

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 4d27300c2..591cbbf27 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -1019,7 +1019,7 @@ static int u32_change(struct net *net, struct
sk_buff *in_skb,
        }

        s = nla_data(tb[TCA_U32_SEL]);
-       sel_size = struct_size(s, keys, s->nkeys);
+       sel_size = struct_size(s, keys, s->nkeys) + sizeof(n->sel);
        if (nla_len(tb[TCA_U32_SEL]) < sel_size) {
                err = -EINVAL;
                goto erridr;