[libvirt] [PATCH RFC] LXC: don't RO mount /proc, /sys when user namespce enabled
If we enabled user ns and provided a uid/gid map, we do not need to mount /proc, /sys as readonly. Leave it to kernel for protection. Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> --- src/lxc/lxc_container.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 1b9e2f2..3b5845a 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -983,6 +983,12 @@ static int lxcContainerMountBasicFS(bool userns_enabled, goto cleanup; } + /* don't readonly mount when userns is enabled */ + if (userns_enabled) { + VIR_FREE(mnt_src); + continue; + } + if (bindOverReadonly && mount(mnt_src, mnt->dst, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL) < 0) { -- 1.9.3
On 12/21/2014 08:57 PM, Chen Hanxiao wrote: s/namespce/namespace/ in the subject line
If we enabled user ns and provided a uid/gid map, we do not need to mount /proc, /sys as readonly. Leave it to kernel for protection.
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> --- src/lxc/lxc_container.c | 6 ++++++ 1 file changed, 6 insertions(+)
I'll leave the actual patch review to someone more familiar with LXC namespace setups -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On Mon, Dec 22, 2014 at 4:12 PM, Eric Blake <eblake@redhat.com> wrote:
On 12/21/2014 08:57 PM, Chen Hanxiao wrote:
s/namespce/namespace/ in the subject line
If we enabled user ns and provided a uid/gid map, we do not need to mount /proc, /sys as readonly. Leave it to kernel for protection.
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> --- src/lxc/lxc_container.c | 6 ++++++ 1 file changed, 6 insertions(+)
I'll leave the actual patch review to someone more familiar with LXC namespace setups
This change will still mount some useless stuff like: { "/.oldroot/proc/sys/net/ipv4", "/proc/sys/net/ipv4", NULL, MS_BIND, false, false, true }, { "/.oldroot/proc/sys/net/ipv6", "/proc/sys/net/ipv6", NULL, MS_BIND, false, false, true }, You can set skipUserNS for these. But I *really* would like to see /proc and /sys mounted RW as default. Please see my comment to: [libvirt] [PATCHv3] lxc: give RW access to /proc/sys/net/ipv[46] to containers -- Thanks, //richard
-----Original Message----- From: Richard Weinberger [mailto:richard.weinberger@gmail.com] Sent: Wednesday, December 24, 2014 5:36 AM To: Eric Blake Cc: Chen, Hanxiao/陈 晗霄; libvir-list@redhat.com Subject: Re: [libvirt] [PATCH RFC] LXC: don't RO mount /proc, /sys when user namespce enabled
On Mon, Dec 22, 2014 at 4:12 PM, Eric Blake <eblake@redhat.com> wrote:
On 12/21/2014 08:57 PM, Chen Hanxiao wrote:
s/namespce/namespace/ in the subject line
If we enabled user ns and provided a uid/gid map, we do not need to mount /proc, /sys as readonly. Leave it to kernel for protection.
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> --- src/lxc/lxc_container.c | 6 ++++++ 1 file changed, 6 insertions(+)
I'll leave the actual patch review to someone more familiar with LXC namespace setups
This change will still mount some useless stuff like: { "/.oldroot/proc/sys/net/ipv4", "/proc/sys/net/ipv4", NULL, MS_BIND, false, false, true }, { "/.oldroot/proc/sys/net/ipv6", "/proc/sys/net/ipv6", NULL, MS_BIND, false, false, true },
You can set skipUserNS for these.
Thanks, I didn't notice that.
But I *really* would like to see /proc and /sys mounted RW as default. Please see my comment to: [libvirt] [PATCHv3] lxc: give RW access to /proc/sys/net/ipv[46] to containers
I see your new comments in that thread. If libvirt enable userns(provided a uid/gid map in XML), it's safe to drop RO mount completely; If not, I'm not sure whether it will bring back compatibility issues. So let's wait for more comments from maintainers. Regards, - Chen
-- Thanks, //richard
Am 24.12.2014 um 03:23 schrieb Chen, Hanxiao:
-----Original Message----- From: Richard Weinberger [mailto:richard.weinberger@gmail.com] Sent: Wednesday, December 24, 2014 5:36 AM To: Eric Blake Cc: Chen, Hanxiao/陈 晗霄; libvir-list@redhat.com Subject: Re: [libvirt] [PATCH RFC] LXC: don't RO mount /proc, /sys when user namespce enabled
On Mon, Dec 22, 2014 at 4:12 PM, Eric Blake <eblake@redhat.com> wrote:
On 12/21/2014 08:57 PM, Chen Hanxiao wrote:
s/namespce/namespace/ in the subject line
If we enabled user ns and provided a uid/gid map, we do not need to mount /proc, /sys as readonly. Leave it to kernel for protection.
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> --- src/lxc/lxc_container.c | 6 ++++++ 1 file changed, 6 insertions(+)
I'll leave the actual patch review to someone more familiar with LXC namespace setups
This change will still mount some useless stuff like: { "/.oldroot/proc/sys/net/ipv4", "/proc/sys/net/ipv4", NULL, MS_BIND, false, false, true }, { "/.oldroot/proc/sys/net/ipv6", "/proc/sys/net/ipv6", NULL, MS_BIND, false, false, true },
You can set skipUserNS for these.
Thanks, I didn't notice that.
But I *really* would like to see /proc and /sys mounted RW as default. Please see my comment to: [libvirt] [PATCHv3] lxc: give RW access to /proc/sys/net/ipv[46] to containers
I see your new comments in that thread. If libvirt enable userns(provided a uid/gid map in XML), it's safe to drop RO mount completely; If not, I'm not sure whether it will bring back compatibility issues.
So let's wait for more comments from maintainers.
I Agree Thanks, //richard
-----Original Message----- From: libvir-list-bounces@redhat.com [mailto:libvir-list-bounces@redhat.com] On Behalf Of Chen Hanxiao Sent: Monday, December 22, 2014 11:57 AM To: libvir-list@redhat.com Subject: [libvirt] [PATCH RFC] LXC: don't RO mount /proc, /sys when user namespce enabled
If we enabled user ns and provided a uid/gid map, we do not need to mount /proc, /sys as readonly. Leave it to kernel for protection.
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> ---
ping
participants (5)
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Chen Hanxiao -
Chen, Hanxiao
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Eric Blake -
Richard Weinberger -
Richard Weinberger