Acked-by: Andrey Vagin <ava...@virtuozzo.com>
On Fri, Dec 23, 2016 at 10:19:01AM +0300, Cyrill Gorcunov wrote: > On Fri, Dec 23, 2016 at 09:59:28AM +0300, Cyrill Gorcunov wrote: > > On Thu, Dec 22, 2016 at 04:45:10PM -0800, Andrey Vagin wrote: > > > > > > Actually, this patch breaks the old behaviour even when MSG_PEEK isn't > > > set. > > > > > > I was thinking a bit more and I don't understand why it is a problem. If > > > we can't fill a buffer, an error will be returned and a user will be able > > > to set peek_offset to get these data again. > > > > A user doesn't have to set peek again, without the patch the internal state > > of sk is context-dependant, which is broken design. Take a look on unix > > sockets code, they DON'T modify offset if something earlier failed for > > exactly same reason. > > Another option -- set offset only iff data copying passed. > --- > From: Cyrill Gorcunov <gorcu...@openvz.org> > Subject: [PATCH rh7 v2] netlink: Don't manipulate @sk_peek_off if data > fetching failed > > When skb_copy_datagram_iovec called to fetch queued data > it may fail with EFAULT and if MSG_PEEK set by a caller > the position get advanced even if data hasn't been read. > So we might loose data bits here on subsequent recvmsg > calls. Instead lets exit early with error. > > In sake of https://jira.sw.ru/browse/PSBM-57921 > > CC: Andrey Vagin <ava...@openvz.org> > Signed-off-by: Cyrill Gorcunov <gorcu...@openvz.org> > --- > net/netlink/af_netlink.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > Index: linux-pcs7.git/net/netlink/af_netlink.c > =================================================================== > --- linux-pcs7.git.orig/net/netlink/af_netlink.c > +++ linux-pcs7.git/net/netlink/af_netlink.c > @@ -2473,11 +2473,12 @@ static int netlink_recvmsg(struct kiocb > > skb_reset_transport_header(data_skb); > err = skb_copy_datagram_iovec(data_skb, skip, msg->msg_iov, copied); > - > - if (flags & MSG_PEEK) > - sk_peek_offset_fwd(sk, copied); > - else > - sk_peek_offset_bwd(sk, skb->len); > + if (!err) { > + if (flags & MSG_PEEK) > + sk_peek_offset_fwd(sk, copied); > + else > + sk_peek_offset_bwd(sk, skb->len); > + } > > if (msg->msg_name) { > struct sockaddr_nl *addr = (struct sockaddr_nl *)msg->msg_name; _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel