From: David Howells <dhowells@redhat.com> To: ebiederm@xmission.com (Eric W. Biederman) Cc: dhowells@redhat.com, trondmy@primarydata.com, mszeredi@redhat.com, linux-nfs@vger.kernel.org, jlayton@redhat.com, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [RFC][PATCH 0/9] Make containers kernel objects Date: Tue, 23 May 2017 17:13:18 +0100 [thread overview] Message-ID: <3612.1495555998@warthog.procyon.org.uk> (raw) In-Reply-To: <87lgpoww67.fsf@xmission.com> Eric W. Biederman <ebiederm@xmission.com> wrote: > Let me suggest a concrete alternative: > > - At the time of mount observer the mounters user namespace. Looking at sget(), I don't think a mounter can see a superblock outside of their namespace. There is something icky in there whereby all automounts are currently transferred into the init_user_ns though (something to fix in my mount-context series) :-/ > - Find the mounters pid namespace. > - If the mounters pid namespace is owned by the mounters user namespace > walk up the pid namespace tree to the first pid namespace owned by > that user namespace. > - If the mounters pid namespace is not owned by the mounters user > namespace fail the mount it is going to need to make upcalls as > will not be possible. Take the following scenario: (1) Create a process with a new network namespace. Set up the network to route out of ethernet port 1. (2) Create a child process with new network and user namespaces. Set up the network to route out of ethernet port 2. (3) Mount an NFS volume in the process created in (2). The mount in (3) will fail unconditionally. > - Hold a reference to the pid namespace that was found. Take the following scenario: (1) Create a process with new network and pid namespaces. Set up the network to route out of ethernet port 1. (2) Create a child process with new network and pid namespaces. Set up the network to route out of ethernet port 2. (3) Mount an NFS volume in the process created in (2). (4) Create another child process with new network and pid namespaces. Set up the network to route out of ethernet port 3. (5) In the process created in (4), access the NFS volume created in (3). The user namespace is the same all the way through. Now you're holding a ref to the pid namespace created in (1) - but that is of no use to you. The upcall must take place in the network namespace that routes out through port 2. David
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com> To: "Eric W. Biederman" <ebiederm@xmission.com> Cc: dhowells@redhat.com, trondmy@primarydata.com, mszeredi@redhat.com, linux-nfs@vger.kernel.org, jlayton@redhat.com, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [RFC][PATCH 0/9] Make containers kernel objects Date: Tue, 23 May 2017 17:13:18 +0100 [thread overview] Message-ID: <3612.1495555998@warthog.procyon.org.uk> (raw) In-Reply-To: <87lgpoww67.fsf@xmission.com> Eric W. Biederman <ebiederm@xmission.com> wrote: > Let me suggest a concrete alternative: > > - At the time of mount observer the mounters user namespace. Looking at sget(), I don't think a mounter can see a superblock outside of their namespace. There is something icky in there whereby all automounts are currently transferred into the init_user_ns though (something to fix in my mount-context series) :-/ > - Find the mounters pid namespace. > - If the mounters pid namespace is owned by the mounters user namespace > walk up the pid namespace tree to the first pid namespace owned by > that user namespace. > - If the mounters pid namespace is not owned by the mounters user > namespace fail the mount it is going to need to make upcalls as > will not be possible. Take the following scenario: (1) Create a process with a new network namespace. Set up the network to route out of ethernet port 1. (2) Create a child process with new network and user namespaces. Set up the network to route out of ethernet port 2. (3) Mount an NFS volume in the process created in (2). The mount in (3) will fail unconditionally. > - Hold a reference to the pid namespace that was found. Take the following scenario: (1) Create a process with new network and pid namespaces. Set up the network to route out of ethernet port 1. (2) Create a child process with new network and pid namespaces. Set up the network to route out of ethernet port 2. (3) Mount an NFS volume in the process created in (2). (4) Create another child process with new network and pid namespaces. Set up the network to route out of ethernet port 3. (5) In the process created in (4), access the NFS volume created in (3). The user namespace is the same all the way through. Now you're holding a ref to the pid namespace created in (1) - but that is of no use to you. The upcall must take place in the network namespace that routes out through port 2. David
next prev parent reply other threads:[~2017-05-23 16:13 UTC|newest] Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-05-22 16:22 [RFC][PATCH 0/9] Make containers kernel objects David Howells 2017-05-22 16:22 ` David Howells 2017-05-22 16:22 ` [PATCH 1/9] containers: Rename linux/container.h to linux/container_dev.h David Howells 2017-05-22 16:22 ` [PATCH 2/9] Implement containers as kernel objects David Howells 2017-08-14 5:47 ` Richard Guy Briggs 2017-08-14 5:47 ` Richard Guy Briggs [not found] ` <20170814054711.GB29957-bcJWsdo4jJjeVoXN4CMphl7TgLCtbB0G@public.gmane.org> 2017-08-16 22:21 ` Paul Moore 2017-08-16 22:21 ` Paul Moore 2017-08-16 22:21 ` Paul Moore 2017-08-16 22:21 ` Paul Moore [not found] ` <CAHC9VhRgPRa7KeMt8G700aeFvqVYc0gMx__82K31TYY6oQQqTw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2017-08-18 8:03 ` Richard Guy Briggs 2017-08-18 8:03 ` Richard Guy Briggs 2017-08-18 8:03 ` Richard Guy Briggs 2017-09-06 14:03 ` Serge E. Hallyn 2017-09-06 14:03 ` Serge E. Hallyn [not found] ` <20170906140341.GA8729-7LNsyQBKDXoIagZqoN9o3w@public.gmane.org> 2017-09-14 5:47 ` Richard Guy Briggs 2017-09-14 5:47 ` Richard Guy Briggs 2017-09-14 5:47 ` Richard Guy Briggs [not found] ` <20170818080300.GQ7187-bcJWsdo4jJjeVoXN4CMphl7TgLCtbB0G@public.gmane.org> 2017-09-06 14:03 ` Serge E. Hallyn 2017-09-08 20:02 ` Paul Moore 2017-09-08 20:02 ` Paul Moore [not found] ` <149547016213.10599.1969443294414531853.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> 2017-08-14 5:47 ` Richard Guy Briggs 2017-05-22 16:22 ` [PATCH 3/9] Provide /proc/containers David Howells 2017-05-22 16:22 ` David Howells 2017-05-22 16:22 ` [PATCH 4/9] Allow processes to be forked and upcalled into a container David Howells 2017-05-22 16:22 ` David Howells 2017-05-22 16:23 ` [PATCH 5/9] Open a socket inside " David Howells 2017-05-22 16:23 ` [PATCH 6/9] Allow fs syscall dfd arguments to take a container fd David Howells 2017-05-22 16:23 ` [PATCH 7/9] Make fsopen() able to initiate mounting into a container David Howells 2017-05-22 16:23 ` [PATCH 8/9] Honour CONTAINER_NEW_EMPTY_FS_NS David Howells 2017-05-22 16:23 ` David Howells 2017-05-22 16:23 ` [PATCH 9/9] Sample program for driving container objects David Howells [not found] ` <149547014649.10599.12025037906646164347.stgit-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> 2017-05-22 16:53 ` [RFC][PATCH 0/9] Make containers kernel objects James Bottomley 2017-05-22 16:53 ` James Bottomley 2017-05-22 17:14 ` Aleksa Sarai 2017-05-22 17:14 ` Aleksa Sarai 2017-05-22 17:27 ` Jessica Frazelle 2017-05-22 17:27 ` Jessica Frazelle 2017-05-22 18:34 ` Jeff Layton 2017-05-22 18:34 ` Jeff Layton [not found] ` <1495478092.2816.17.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> 2017-05-22 19:21 ` James Bottomley 2017-05-22 19:21 ` James Bottomley 2017-05-22 19:21 ` James Bottomley 2017-05-22 22:14 ` Jeff Layton [not found] ` <1495480860.9050.18.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org> 2017-05-22 22:14 ` Jeff Layton 2017-05-23 10:35 ` Ian Kent 2017-05-23 10:35 ` Ian Kent 2017-05-23 10:35 ` Ian Kent 2017-05-23 9:38 ` Ian Kent 2017-05-23 9:38 ` Ian Kent 2017-05-23 9:38 ` Ian Kent [not found] ` <1495472039.2757.19.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org> 2017-05-22 17:14 ` Aleksa Sarai 2017-05-22 17:27 ` Jessica Frazelle 2017-05-22 18:34 ` Jeff Layton 2017-05-23 9:38 ` Ian Kent 2017-05-23 13:52 ` David Howells [not found] ` <f167feeb-e653-12e3-eec8-24162f7f7c07-l3A5Bk7waGM@public.gmane.org> 2017-05-23 14:53 ` David Howells 2017-05-23 14:53 ` David Howells 2017-05-23 14:56 ` Eric W. Biederman 2017-05-23 14:56 ` Eric W. Biederman [not found] ` <2446.1495551216-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> 2017-05-23 14:56 ` Eric W. Biederman 2017-05-23 15:14 ` David Howells 2017-05-23 15:14 ` David Howells [not found] ` <2961.1495552481-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> 2017-05-23 15:17 ` Eric W. Biederman 2017-05-23 15:17 ` Eric W. Biederman [not found] ` <87bmqjmwl5.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> 2017-05-23 15:44 ` James Bottomley 2017-05-23 15:44 ` James Bottomley 2017-05-23 15:44 ` James Bottomley [not found] ` <1495554267.27369.9.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org> 2017-05-23 16:36 ` David Howells 2017-05-23 16:36 ` David Howells [not found] ` <3860.1495557363-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> 2017-05-24 8:26 ` Eric W. Biederman 2017-05-24 8:26 ` Eric W. Biederman 2017-05-24 9:16 ` Ian Kent 2017-05-24 9:16 ` Ian Kent [not found] ` <87k256ek3e.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> 2017-05-24 9:16 ` Ian Kent [not found] ` <87zie3mxkc.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> 2017-05-23 15:14 ` David Howells 2017-05-22 17:11 ` Jessica Frazelle 2017-05-22 17:11 ` Jessica Frazelle 2017-05-22 19:04 ` Eric W. Biederman 2017-05-22 19:04 ` Eric W. Biederman 2017-05-22 22:22 ` Jeff Layton 2017-05-22 22:22 ` Jeff Layton 2017-05-23 12:54 ` Eric W. Biederman 2017-05-23 12:54 ` Eric W. Biederman 2017-05-23 14:27 ` Jeff Layton 2017-05-23 14:27 ` Jeff Layton 2017-05-23 14:30 ` Djalal Harouni 2017-05-23 14:30 ` Djalal Harouni 2017-05-23 14:54 ` Colin Walters 2017-05-23 14:54 ` Colin Walters 2017-05-23 15:31 ` Jeff Layton 2017-05-23 15:31 ` Jeff Layton 2017-05-23 15:35 ` Colin Walters 2017-05-23 15:35 ` Colin Walters 2017-05-23 15:30 ` David Howells 2017-05-23 14:23 ` Djalal Harouni 2017-05-23 14:23 ` Djalal Harouni 2017-05-27 17:45 ` Trond Myklebust 2017-05-27 17:45 ` Trond Myklebust 2017-05-27 19:10 ` James Bottomley 2017-05-27 19:10 ` James Bottomley 2017-05-30 1:03 ` Ian Kent 2017-05-30 1:03 ` Ian Kent 2017-05-23 10:09 ` Ian Kent 2017-05-23 10:09 ` Ian Kent 2017-05-23 13:52 ` David Howells 2017-05-23 13:52 ` David Howells 2017-05-23 15:02 ` James Bottomley 2017-05-23 15:02 ` James Bottomley [not found] ` <32556.1495547529-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> 2017-05-23 15:02 ` James Bottomley 2017-05-23 15:23 ` Eric W. Biederman 2017-05-23 15:23 ` Eric W. Biederman 2017-05-23 15:12 ` David Howells 2017-05-23 15:12 ` David Howells 2017-05-23 15:33 ` Eric W. Biederman 2017-05-23 15:33 ` Eric W. Biederman 2017-05-23 16:13 ` David Howells [this message] 2017-05-23 16:13 ` David Howells
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