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
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <54EEDF9C.20302@6wind.com>
Date:	Thu, 26 Feb 2015 09:55:56 +0100
From:	Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
CC:	Eugene Yakubovich <eugene.yakubovich@...eos.com>,
	netdev@...r.kernel.org
Subject: Re: What are the intended semantics of IFLA_LINK_NETNSID?

Le 25/02/2015 20:03, Eric W. Biederman a écrit :
>
> Reading through the code of rtnl_newlink I am perplexed with what your
> intended semantics of IFLA_LINK_NETNSID are supposed to be.
>
> My expectation was something with the same semantics IFLA_NET_NS_PID and
> IFLA_NET_NS_FD just a different data representation and something that
> could be used in more netlink messages, so you could report the network
> namespace where the other end of a tunnel or the the network namespace
> of an underlying device is.
>
> Being very slow I would expect that ILFA_LINK_NETNSID would replace
> dest_net or possibly net in rtnl_newlink but it does not replace either
> of those completely.  Which causes me to think that the implementation
> of IFLA_LINK_NETNSID in rtnl_newlink is broken.
>
> I suspect the correct fix for rtnl_newlink is to just use
> IFLA_LINK_NETNSID in rtnl_link_get_net and have it be an alternative way
> of setting dest_net.  But you may intend some different semantics that
> I don't understand.
ILFA_LINK_NETNSID is used to point to the i/o netns of the interface, ie the
opposite netns of dest_net.
The interface is first created in link_net and moved at the end in dest_net.

IP tunnels interfaces (ipip, sit, ip6_tunnels, gre[v6]) does not use src_net,
thus when you create an ipip interface by specifying an attribute
IFLA_NET_NS_PID it will result to an interface which is not across two netns but
only in the netns pointed by IFLA_NET_NS_PID. If you use IFLA_LINK_NETNSID, it
allows you to create this kind of x-netns interfaces.
In fact, the goal of this attribute is to replace the two following command by
only one:
ip link add foo ...
ip link set foo netns bar
=> ip link add foo link-netnsid barID


Regards,
Nicolas
--
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