On Wed, Mar 14, 2018 at 07:05:33PM +0800, Xin Long wrote:
> This patch is to add SCTP_AUTH_FREE_KEY type for AUTHENTICATION_EVENT,
> as described in section 6.1.8 of RFC6458.
>
> SCTP_AUTH_FREE_KEY: This report indicates that the SCTP
> implementation will no longer use the key identifier specified
> in auth_keynumber.
>
> After deactivating a key, it would never be used again, which means
> it's refcnt can't be held/increased by new chunks. But there may be
> some chunks in out queue still using it. So only when refcnt is 1,
> which means no chunk in outqueue is using/holding this key either,
> this EVENT would be sent.
>
> When users receive this notification, they could do DEL_KEY sockopt to
> remove this shkey, and also tell the peer that this key won't be used
> in any chunk thoroughly from now on, then the peer can remove it as
> well safely.
>
> Signed-off-by: Xin Long <lucien....@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leit...@gmail.com>
> ---
> include/uapi/linux/sctp.h | 6 +++++-
> net/sctp/auth.c | 14 ++++++++++++++
> net/sctp/sm_make_chunk.c | 20 +++++++++++++++++++-
> net/sctp/sm_statefuns.c | 2 +-
> net/sctp/socket.c | 19 ++++++++++++++++++-
> 5 files changed, 57 insertions(+), 4 deletions(-)
>
> diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
> index 08fc313..18ebbfe 100644
> --- a/include/uapi/linux/sctp.h
> +++ b/include/uapi/linux/sctp.h
> @@ -518,7 +518,11 @@ struct sctp_authkey_event {
> sctp_assoc_t auth_assoc_id;
> };
>
> -enum { SCTP_AUTH_NEWKEY = 0, };
> +enum {
> + SCTP_AUTH_NEW_KEY,
> +#define SCTP_AUTH_NEWKEY SCTP_AUTH_NEW_KEY /* compatible with
> before */
> + SCTP_AUTH_FREE_KEY,
> +};
>
> /*
> * 6.1.9. SCTP_SENDER_DRY_EVENT
> diff --git a/net/sctp/auth.c b/net/sctp/auth.c
> index a073123..e64630c 100644
> --- a/net/sctp/auth.c
> +++ b/net/sctp/auth.c
> @@ -992,6 +992,20 @@ int sctp_auth_deact_key_id(struct sctp_endpoint *ep,
> if (!found)
> return -EINVAL;
>
> + /* refcnt == 1 and !list_empty mean it's not being used anywhere
> + * and deactivated will be set, so it's time to notify userland
> + * that this shkey can be freed.
> + */
> + if (asoc && !list_empty(&key->key_list) &&
> + refcount_read(&key->refcnt) == 1) {
> + struct sctp_ulpevent *ev;
> +
> + ev = sctp_ulpevent_make_authkey(asoc, key->key_id,
> + SCTP_AUTH_FREE_KEY, GFP_KERNEL);
> + if (ev)
> + asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
> + }
> +
> key->deactivated = 1;
>
> return 0;
> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
> index 10f071c..cc20bc3 100644
> --- a/net/sctp/sm_make_chunk.c
> +++ b/net/sctp/sm_make_chunk.c
> @@ -89,8 +89,26 @@ static void sctp_control_release_owner(struct sk_buff *skb)
> {
> struct sctp_chunk *chunk = skb_shinfo(skb)->destructor_arg;
>
> - if (chunk->shkey)
> + if (chunk->shkey) {
> + struct sctp_shared_key *shkey = chunk->shkey;
> + struct sctp_association *asoc = chunk->asoc;
> +
> + /* refcnt == 2 and !list_empty mean after this release, it's
> + * not being used anywhere, and it's time to notify userland
> + * that this shkey can be freed if it's been deactivated.
> + */
> + if (shkey->deactivated && !list_empty(&shkey->key_list) &&
> + refcount_read(&shkey->refcnt) == 2) {
> + struct sctp_ulpevent *ev;
> +
> + ev = sctp_ulpevent_make_authkey(asoc, shkey->key_id,
> + SCTP_AUTH_FREE_KEY,
> + GFP_KERNEL);
> + if (ev)
> + asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
> + }
> sctp_auth_shkey_release(chunk->shkey);
> + }
> }
>
> static void sctp_control_set_owner_w(struct sctp_chunk *chunk)
> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
> index 792e0e2..1e41dee 100644
> --- a/net/sctp/sm_statefuns.c
> +++ b/net/sctp/sm_statefuns.c
> @@ -4246,7 +4246,7 @@ enum sctp_disposition sctp_sf_eat_auth(struct net *net,
> struct sctp_ulpevent *ev;
>
> ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
> - SCTP_AUTH_NEWKEY, GFP_ATOMIC);
> + SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
>
> if (!ev)
> return -ENOMEM;
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 65cc354..aeecdd6 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -8166,8 +8166,25 @@ static void sctp_wfree(struct sk_buff *skb)
> sk->sk_wmem_queued -= skb->truesize;
> sk_mem_uncharge(sk, skb->truesize);
>
> - if (chunk->shkey)
> + if (chunk->shkey) {
> + struct sctp_shared_key *shkey = chunk->shkey;
> +
> + /* refcnt == 2 and !list_empty mean after this release, it's
> + * not being used anywhere, and it's time to notify userland
> + * that this shkey can be freed if it's been deactivated.
> + */
> + if (shkey->deactivated && !list_empty(&shkey->key_list) &&
> + refcount_read(&shkey->refcnt) == 2) {
> + struct sctp_ulpevent *ev;
> +
> + ev = sctp_ulpevent_make_authkey(asoc, shkey->key_id,
> + SCTP_AUTH_FREE_KEY,
> + GFP_KERNEL);
> + if (ev)
> + asoc->stream.si->enqueue_event(&asoc->ulpq, ev);
> + }
> sctp_auth_shkey_release(chunk->shkey);
> + }
>
> sock_wfree(skb);
> sctp_wake_up_waiters(sk, asoc);
> --
> 2.1.0
>
