Re: [PATCH 03/10] vsock: owner field is specific to VMCI

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Hi

On Wed, Oct 27, 2021 at 12:13 PM Jorgen Hansen <jhansen@vmware.com> wrote:
>
>
> > On 26 Oct 2021, at 13:16, Stefano Garzarella <sgarzare@redhat.com> wrote:
> >
> > CCing Jorgen.
> >
> > On Thu, Oct 21, 2021 at 04:37:07PM +0400, Marc-André Lureau wrote:
> >> This field isn't used by other transports.
> >
> > If the field is used only in the VMCI transport, maybe it's better to
> > move the field and the code in that transport.
>
> If the transport needs initialize these fields, that should happen when we
> call vsock_assign_transport. So we would need to validate that
> get_current_cred() gets the right credentials and that the parent of a
> socket has an Initialised owner field at that point in time.
>
> sock_assign_transport may be called when processing an
> incoming packet when a remote connects to a listening socket,
> and in that case, the owner will be based on the parent socket.
> If the parent socket hasn’t been assigned a transport (and as I
> remember it, that isn’t the case for a listening socket), then it
> isn’t possible to initialize the owner field at this point using
> the value from the parent. So the initialisation of the fields
> probably have to stay in af_vsock.c as part of the generic structure.
>
> Is there a particular reason to do this change as part of this series
> of patches?

No particular reason, it was just related code.

thanks

>
> Thanks,
> Jorgen
>
> > Thanks,
> > Stefano
> >
> >>
> >> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> >> ---
> >> include/net/af_vsock.h   | 2 ++
> >> net/vmw_vsock/af_vsock.c | 6 ++++++
> >> 2 files changed, 8 insertions(+)
> >>
> >> diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
> >> index ab207677e0a8..e626d9484bc5 100644
> >> --- a/include/net/af_vsock.h
> >> +++ b/include/net/af_vsock.h
> >> @@ -41,7 +41,9 @@ struct vsock_sock {
> >>                                       * cached peer?
> >>                                       */
> >>      u32 cached_peer;  /* Context ID of last dgram destination check. */
> >> +#if IS_ENABLED(CONFIG_VMWARE_VMCI_VSOCKETS)
> >>      const struct cred *owner;
> >> +#endif
> >>      /* Rest are SOCK_STREAM only. */
> >>      long connect_timeout;
> >>      /* Listening socket that this came from. */
> >> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> >> index e2c0cfb334d2..1925682a942a 100644
> >> --- a/net/vmw_vsock/af_vsock.c
> >> +++ b/net/vmw_vsock/af_vsock.c
> >> @@ -761,7 +761,9 @@ static struct sock *__vsock_create(struct net *net,
> >>      psk = parent ? vsock_sk(parent) : NULL;
> >>      if (parent) {
> >>              vsk->trusted = psk->trusted;
> >> +#if IS_ENABLED(CONFIG_VMWARE_VMCI_VSOCKETS)
> >>              vsk->owner = get_cred(psk->owner);
> >> +#endif
> >>              vsk->connect_timeout = psk->connect_timeout;
> >>              vsk->buffer_size = psk->buffer_size;
> >>              vsk->buffer_min_size = psk->buffer_min_size;
> >> @@ -769,7 +771,9 @@ static struct sock *__vsock_create(struct net *net,
> >>              security_sk_clone(parent, sk);
> >>      } else {
> >>              vsk->trusted = ns_capable_noaudit(&init_user_ns, CAP_NET_ADMIN);
> >> +#if IS_ENABLED(CONFIG_VMWARE_VMCI_VSOCKETS)
> >>              vsk->owner = get_current_cred();
> >> +#endif
> >>              vsk->connect_timeout = VSOCK_DEFAULT_CONNECT_TIMEOUT;
> >>              vsk->buffer_size = VSOCK_DEFAULT_BUFFER_SIZE;
> >>              vsk->buffer_min_size = VSOCK_DEFAULT_BUFFER_MIN_SIZE;
> >> @@ -833,7 +837,9 @@ static void vsock_sk_destruct(struct sock *sk)
> >>      vsock_addr_init(&vsk->local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
> >>      vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
> >>
> >> +#if IS_ENABLED(CONFIG_VMWARE_VMCI_VSOCKETS)
> >>      put_cred(vsk->owner);
> >> +#endif
> >> }
> >>
> >> static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
> >> --
> >> 2.33.0.721.g106298f7f9
> >>
> >
>