On Tue, Feb 23, 2021 at 9:53 AM Jakub Sitnicki <jakub@xxxxxxxxxxxxxx> wrote: > Based on what I've seen around, mask for sanitizing tagged pointers is > usually derived from the flag(s). For instance: > > #define SKB_DST_NOREF 1UL > #define SKB_DST_PTRMASK ~(SKB_DST_NOREF) > > #define SK_USER_DATA_NOCOPY 1UL > #define SK_USER_DATA_BPF 2UL /* Managed by BPF */ > #define SK_USER_DATA_PTRMASK ~(SK_USER_DATA_NOCOPY | SK_USER_DATA_BPF) > > Using ~(BPF_F_INGRESS) expression would be like substituting mask > definition. Yes, that is why I said we need a mask. > > Alternatively we could clear _skb_refdest after clone, but before > enqueuing the skb in ingress_skb. And only for when we're redirecting. > > I believe that would be in sk_psock_skb_redirect, right before skb_queue_tail. Hmm? We definitely cannot clear skb->_sk_redir there, as it is used after enqueued in ingress_skb, that is in sk_psock_backlog(). Thanks.
