lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 08 Sep 2014 10:11:37 -0700 From: Eric Dumazet <eric.dumazet@...il.com> To: Alexander Duyck <alexander.h.duyck@...el.com> Cc: netdev@...r.kernel.org, richardcochran@...il.com, davem@...emloft.net Subject: Re: [PATCH net-next] skb: Add documentation for skb_clone_sk On Mon, 2014-09-08 at 12:18 -0400, Alexander Duyck wrote: > This change adds some documentation to the call skb_clone_sk. This is > meant to help clarify the purpose of the function for other developers. > > Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com> > --- > net/core/skbuff.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index a18dfb0..3f83a8a 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -3511,6 +3511,17 @@ struct sk_buff *sock_dequeue_err_skb(struct sock *sk) > } > EXPORT_SYMBOL(sock_dequeue_err_skb); > > +/** > + * skb_clone_sk - create clone of skb, and take reference to socket > + * @skb: the skb to clone > + * > + * For functions such as timestamping it is necessary to clone an skb and > + * hold a reference to the socket for it until the hardware delivers the > + * actual timestamp or the timestamp is timed out. As as such this > + * function is useful for creating a clone to later be handed off to > + * skb_complete_tx_timestamp or kfree_skb to take care of cleaning up > + * the reference handling for the socket. > + */ > struct sk_buff *skb_clone_sk(struct sk_buff *skb) > { > struct sock *sk = skb->sk; Note that I have serious doubts about the atomic_inc_not_zero() here. At this point, we need to have consistent refcounting on the socket. If we decide the reference is against sk_refcnt, then current sk_refcnt cannot be 0 at this point. This might hide a very serious bug. In TCP tx path for example, we do not take reference on sk_refcnt for each packet, but a reference on sk_wmem_alloc If skb destructor is sock_wfree() or tcp_wfree(), then we should take an extra reference on sk_wmem_alloc instead of sk_refcnt. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists