From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
To: Greg Kroah-Hartman
<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
Cc: Linux Containers
<containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
Kay Sievers <kay.sievers-tD+1rO4QERM@public.gmane.org>,
Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
devel <devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>,
lxc-devel
<lxc-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>,
mhw <mhw-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
Stephane Graber
<stgraber-GeWIH/nMZzLQT0dZR+AlfA@public.gmane.org>
Subject: Re: Device Namespaces
Date: Wed, 02 Oct 2013 15:45:46 -0700 [thread overview]
Message-ID: <871u43pa05.fsf@xmission.com> (raw)
In-Reply-To: <20131001205718.GA17036-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org> (Greg Kroah-Hartman's message of "Tue, 1 Oct 2013 13:57:18 -0700")
I think libudev is a solution to a completely different problem. It is
possible I am blind but I just don't see how libudev even attempts to
solve the problem.
The desire is to plop a distro install into a subdirectory. Fire up a
container around it, and let the distro's userspace do it's thing to
manage hotplug events.
devtmpfs can be faked fairly easily.
I don't know about sysfs.
Sending events that say you have hotplugged is the largest practical
problem.
On the minimal side I think the patch below is enough to let us fake up
uevents for the container and make things work. I have heard the words
faking uevents and is a bad thing. But I have not heard a reason or seen
any attempt at explanation. My guess is that we are simply talking
about different problems.
I would like to see someone wire up all of the userspace bits and see
how well hotplug can be made to work before I walk down the path
represented by this patch but it seems reasonable. But I do have
anecdotal reports from someone who walked a similar path that this is
enough to bring up a full desktop system in a container.
Eric
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 7a6c396a263b..46d05783da82 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -38,6 +38,7 @@ extern void netlink_table_ungrab(void);
#define NL_CFG_F_NONROOT_RECV (1 << 0)
#define NL_CFG_F_NONROOT_SEND (1 << 1)
+#define NL_CFG_F_IMPERSONATE_KERN (1 << 2)
/* optional Netlink kernel configuration parameters */
struct netlink_kernel_cfg {
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 52e5abbc41db..f75e34397df8 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -375,9 +375,12 @@ static int uevent_net_init(struct net *net)
struct uevent_sock *ue_sk;
struct netlink_kernel_cfg cfg = {
.groups = 1,
- .flags = NL_CFG_F_NONROOT_RECV,
+ .flags = NL_CFG_F_NONROOT_RECV | NL_CFG_F_IMPERSONATE_KERN,
};
+ if (net->user_ns != &init_user_ns)
+ return 0;
+
ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL);
if (!ue_sk)
return -ENOMEM;
@@ -399,6 +402,9 @@ static void uevent_net_exit(struct net *net)
{
struct uevent_sock *ue_sk;
+ if (net->user_ns != &init_user_ns)
+ return;
+
mutex_lock(&uevent_sock_mutex);
list_for_each_entry(ue_sk, &uevent_sock_list, list) {
if (sock_net(ue_sk->sk) == net)
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 0c61b59175dc..71863cc465eb 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1252,7 +1252,7 @@ static int netlink_release(struct socket *sock)
skb_queue_purge(&sk->sk_write_queue);
- if (nlk->portid) {
+ if (sk_hashed(sk)) {
struct netlink_notify n = {
.net = sock_net(sk),
.protocol = sk->sk_protocol,
@@ -1409,11 +1409,21 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
return err;
}
- if (nlk->portid) {
+ if (sk_hashed(sk)) {
if (nladdr->nl_pid != nlk->portid)
return -EINVAL;
} else {
- err = nladdr->nl_pid ?
+ bool autobind = nladdr->nl_pid == 0;
+ if (nladdr->nl_pid == 0 && (nladdr->nl_pad == 0xffff)) {
+ if (!(nl_table[sk->sk_protocol].flags & NL_CFG_F_IMPERSONATE_KERN))
+ return -EPERM;
+ if (net->user_ns == &init_user_ns)
+ return -EPERM;
+ if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+ return -EPERM;
+ autobind = false;
+ }
+ err = !autobind ?
netlink_insert(sk, net, nladdr->nl_pid) :
netlink_autobind(sock);
if (err)
@@ -1467,7 +1477,7 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
if (nladdr->nl_groups && !netlink_capable(sock, NL_CFG_F_NONROOT_SEND))
return -EPERM;
- if (!nlk->portid)
+ if (!sk_hashed(sk))
err = netlink_autobind(sock);
if (err == 0) {
@@ -2228,7 +2238,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
dst_group = nlk->dst_group;
}
- if (!nlk->portid) {
+ if (!sk_hashed(sk)) {
err = netlink_autobind(sock);
if (err)
goto out;
next prev parent reply other threads:[~2013-10-02 22:45 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-22 17:43 RFC: Device Namespaces Oren Laadan
[not found] ` <CAA4jN2aw4zEW=UfKCyqaOvXnbiRb_J9srfCn4OXTFzc6vWBM4A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-22 18:21 ` Serge Hallyn
2013-08-26 10:11 ` Oren Laadan
[not found] ` <CAA4jN2YL7Lfu2+DW-i+MovFxWEhJfT4aBBKREU_vy7JX9TKGHA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-06 17:50 ` Eric W. Biederman
[not found] ` <8761udlu0d.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-09-08 12:28 ` Amir Goldstein
[not found] ` <CAA2m6vexArJ+6jFbK80Amstk=LK30=XDNHdBHSswP=LgpSP-6A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-09 0:51 ` Eric W. Biederman
[not found] ` <871u4yddg4.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-09-10 7:09 ` Amir Goldstein
[not found] ` <CAA2m6vc_kWWGDWcdjk26N3YvTqZySLFxPQRjOD9_ypBOka2+GQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-25 11:05 ` Janne Karhunen
[not found] ` <CAE=NcrbyFFoMn2nfBA_=ZtwD=eGLvqK=L-U9MuGrtJFLZfZppw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-25 20:23 ` Eric W. Biederman
[not found] ` <87ioxo4pm5.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-09-25 21:17 ` [lxc-devel] " Jeremy Andrus
[not found] ` <AD5F7BD2-0166-46BD-AB14-463C0E88BC92-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2013-09-25 21:47 ` Eric W. Biederman
[not found] ` <8738osr2ue.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-09-29 17:56 ` Amir Goldstein
2013-09-25 21:34 ` Eric W. Biederman
[not found] ` <87bo3gshz5.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-09-26 5:33 ` Greg Kroah-Hartman
[not found] ` <20130926053320.GB3725-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-09-26 8:25 ` Janne Karhunen
[not found] ` <CAE=NcrbPXGWU8FUgwchXyL5HjXf+4AKbgUWGe1ZO=Xcq=iV-Lg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-26 13:56 ` Greg Kroah-Hartman
[not found] ` <20130926135604.GA16624-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-09-26 17:01 ` Janne Karhunen
[not found] ` <CAE=NcrY3xC1AF_GV2b1KsF7AwYZTuGBuKLS5yBUWoWcmKU4YBg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-26 17:07 ` Greg Kroah-Hartman
[not found] ` <20130926170757.GA9345-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-09-26 17:56 ` Janne Karhunen
2013-09-30 15:37 ` James Bottomley
[not found] ` <1380555439.2161.5.camel-sFMDBYUN5F8GjUHQrlYNx2Wm91YjaHnnhRte9Li2A+AAvxtiuMwx3w@public.gmane.org>
2013-09-30 16:11 ` Greg Kroah-Hartman
[not found] ` <20130930161117.GA26459-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-09-30 16:33 ` James Bottomley
2013-10-01 6:19 ` Janne Karhunen
[not found] ` <CAE=NcrYV2RiMV7PcwEjFGFRBrz9XdZGs86Wau2a+6xpYN2aEHA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-10-01 17:27 ` Andy Lutomirski
[not found] ` <CALCETrWWoHzuJcnfEUY+cFpOgT5gnG8U1cVbCW0_8V7Z_v6DJw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-10-01 17:53 ` Serge E. Hallyn
[not found] ` <20131001175345.GA4145-7LNsyQBKDXoIagZqoN9o3w@public.gmane.org>
2013-10-01 19:51 ` Eric W. Biederman
[not found] ` <87had0wz07.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-01 20:46 ` Serge Hallyn
2013-10-01 22:59 ` [lxc-devel] " Michael H. Warfield
2013-10-02 22:55 ` Eric W. Biederman
2013-10-01 20:57 ` Greg Kroah-Hartman
[not found] ` <20131001205718.GA17036-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-10-02 22:45 ` Eric W. Biederman [this message]
2013-10-01 22:19 ` Michael H. Warfield
2013-10-01 18:36 ` Janne Karhunen
2013-10-01 17:33 ` Greg Kroah-Hartman
[not found] ` <20131001173342.GA19267-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-10-01 18:23 ` Janne Karhunen
2013-10-28 23:31 ` Andrey Wagin
2013-08-29 19:06 ` RFC: " Andy Lutomirski
[not found] ` <521F9BBE.2070505-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>
2013-09-03 19:35 ` [lxc-devel] " Stéphane Graber
2013-09-29 19:28 Amir Goldstein
[not found] ` <CAA2m6veny-7_ONMA973Wu36U4kz4gAuw0dpodkb8+GZDv6VNBQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-29 20:06 ` Greg Kroah-Hartman
[not found] ` <20130929200620.GA31304-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2013-09-30 15:36 ` Michael H. Warfield
2013-10-03 0:44 ` Eric W. Biederman
[not found] ` <87a9iri3ot.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2013-10-03 0:59 ` Eric W. Biederman
2013-10-03 8:58 ` Amir Goldstein
[not found] ` <CAA2m6vc3OFmS9VwiTavRzPqhn+qoe6vDCO2sitXpEQ8a1JVyfg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-10-03 9:17 ` Eric W. Biederman
2021-06-08 9:38 device namespaces Enrico Weigelt, metux IT consult
2021-06-08 12:30 ` Christian Brauner
2021-06-08 12:41 ` Greg Kroah-Hartman
2021-06-08 14:10 ` Hannes Reinecke
2021-06-08 14:29 ` Christian Brauner
2021-06-08 15:54 ` Hannes Reinecke
2021-06-08 17:16 ` Eric W. Biederman
2021-06-09 6:38 ` Christian Brauner
2021-06-09 7:02 ` Hannes Reinecke
2021-06-09 7:21 ` Christian Brauner
2021-06-09 7:54 ` Hannes Reinecke
2021-06-09 8:09 ` Christian Brauner
2021-06-11 18:14 ` Eric W. Biederman
2021-06-14 7:49 ` Enrico Weigelt, metux IT consult
2021-06-14 8:22 ` Greg KH
2021-06-14 17:36 ` Eric W. Biederman
2021-06-15 11:24 ` Enrico Weigelt, metux IT consult
2021-06-15 11:33 ` Greg KH
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