From: ebiederm@xmission•com (Eric W. Biederman)
To: "Serge E. Hallyn" <serue@us•ibm.com>
Cc: Daniel Lezcano <daniel.lezcano@free•fr>,
Pavel Emelyanov <xemul@parallels•com>,
Sukadev Bhattiprolu <sukadev@linux•vnet.ibm.com>,
Linux Netdev List <netdev@vger•kernel.org>,
containers@lists•linux-foundation.org,
Netfilter Development Mailinglist
<netfilter-devel@vger•kernel.org>,
Ben Greear <greearb@candelatech•com>
Subject: Re: [RFC][PATCH] ns: Syscalls for better namespace sharing control.
Date: Mon, 08 Mar 2010 09:35:21 -0800 [thread overview]
Message-ID: <m1pr3eu36u.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20100308170719.GD6399@us.ibm.com> (Serge E. Hallyn's message of "Mon\, 8 Mar 2010 11\:07\:19 -0600")
"Serge E. Hallyn" <serue@us•ibm.com> writes:
> Quoting Eric W. Biederman (ebiederm@xmission•com):
>>
>> I have take an snapshot of my development tree and placed it at.
>>
>>
>> git://git.kernel.org/pub/scm/linux/people/ebiederm/linux-2.6.33-nsfd-v5.git
>>
>>
>> >> I am going to explore a bit more. Given that nsfd is using the same
>> >> permission checks as a proc file, I think I can just make it a proc
>> >> file. Something like "/proc/<pid>/ns/net". With a little luck that
>> >> won't suck too badly.
>> >>
>> > Ah ! yes. Good idea.
>>
>> It is a hair more code to use proc files but nothing worth counting.
>>
>> Probably the biggest thing I am aware of right now in my development
>> tree is in getting uids to pass properly between unix domain sockets
>> I would up writing this cred_to_ucred function.
>>
>> Serge can you take a look and check my logic, and do you have
>> any idea of where we should place something like pid_vnr but
>> for the uid namespace?
>
> Well my first thought was user_namespace, but I'm thinking kernel/cred.c is
> the best place for it.
Thanks.
>> void cred_to_ucred(struct pid *pid, const struct cred *cred,
>> struct ucred *ucred)
>> {
>> ucred->pid = pid_vnr(pid);
>> ucred->uid = ucred->gid = -1;
>> if (cred) {
>> struct user_namespace *cred_ns = cred->user->user_ns;
>> struct user_namespace *current_ns = current_user_ns();
>> struct user_namespace *tmp;
>>
>> if (likely(cred_ns == current_ns)) {
>> ucred->uid = cred->euid;
>> ucred->gid = cred->egid;
>> } else {
>> /* Is cred in a child user namespace */
>> tmp = cred_ns;
>> do {
>> tmp = tmp->creator->user_ns;
>> if (tmp == current_ns) {
>
> Hmm, I think you want to catch one level up - so the creator itself
> is in current_user_ns, so
>
> do {
> if (tmp->creator->user_ns == current_ns) {
> ucred->uid = tmp->creator->uid;
> ucred->gid = tmp->creator_gid;
> return;
> }
> tmp = tmp->creator->user_ns;
> } while (tmp != &init_user_ns);
Good catch.
>> ucred->uid = tmp->creator->uid;
>> ucred->gid = overflowgid;
>
> should we start recording a user_ns->creator_gid
> instead?
I had a similar question. Possibly we can just grab the creators cred.
>> return;
>> }
>> } while (tmp != &init_user_ns);
>>
>> /* Is cred the creator of my user namespace,
>> * or the creator of one of it's parents?
>> */
>> for( tmp = current_ns; tmp != &init_user_ns;
>> tmp = tmp->creator->user_ns) {
>> if (cred->user == tmp->creator) {
>> ucred->uid = 0;
>> ucred->gid = 0;
>> return;
>> }
>> }
>
> That looks right.
>
>> /* No user namespace relationship so no mapping */
>> ucred->uid = overflowuid;
>> ucred->gid = overflowgid;
>> }
>> }
>> }
Eric
next prev parent reply other threads:[~2010-03-08 17:35 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-14 14:05 RFC: netfilter: nf_conntrack: add support for "conntrack zones" Patrick McHardy
2010-01-14 15:05 ` jamal
2010-01-14 15:37 ` Patrick McHardy
2010-01-14 17:33 ` jamal
2010-01-15 10:15 ` Patrick McHardy
2010-01-15 15:19 ` jamal
2010-02-22 20:46 ` Eric W. Biederman
2010-02-22 21:55 ` jamal
2010-02-22 23:17 ` Eric W. Biederman
[not found] ` <m1wry46es9.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-23 13:27 ` jamal
2010-02-23 14:07 ` Eric W. Biederman
2010-02-23 14:20 ` jamal
2010-02-23 20:00 ` Eric W. Biederman
2010-02-23 23:09 ` jamal
2010-02-24 1:43 ` Eric W. Biederman
2010-02-25 20:57 ` [RFC][PATCH] ns: Syscalls for better namespace sharing control Eric W. Biederman
2010-02-25 21:31 ` Daniel Lezcano
2010-02-25 21:49 ` Eric W. Biederman
2010-02-25 22:13 ` Daniel Lezcano
2010-02-25 22:31 ` Eric W. Biederman
2010-02-26 20:35 ` Eric W. Biederman
2010-02-25 21:46 ` Matt Helsley
2010-02-25 21:54 ` Eric W. Biederman
2010-02-26 0:53 ` Eric W. Biederman
2010-02-26 1:09 ` Matt Helsley
2010-02-26 1:26 ` Eric W. Biederman
2010-02-26 3:15 ` [RFC][PATCH] ns: Syscalls for better namespace sharing control. v2 Eric W. Biederman
[not found] ` <m18wagy9f3.fsf_-_-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-03-03 20:29 ` Jonathan Corbet
2010-03-03 20:50 ` Eric W. Biederman
[not found] ` <m1pr3t2fvl.fsf_-_-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-26 21:13 ` [RFC][PATCH] ns: Syscalls for better namespace sharing control Pavel Emelyanov
2010-02-26 21:24 ` Eric W. Biederman
2010-02-26 21:34 ` Pavel Emelyanov
2010-02-26 21:42 ` Eric W. Biederman
2010-02-26 21:58 ` Oren Laadan
2010-02-26 22:16 ` Eric W. Biederman
2010-02-26 22:52 ` Oren Laadan
2010-02-26 23:13 ` Eric W. Biederman
2010-02-27 8:30 ` Pavel Emelyanov
2010-02-27 9:04 ` Eric W. Biederman
[not found] ` <m1mxyvrqvk.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-27 9:21 ` Pavel Emelyanov
2010-02-27 9:42 ` Eric W. Biederman
2010-02-27 16:16 ` Pavel Emelyanov
2010-02-27 19:08 ` Eric W. Biederman
2010-02-27 19:29 ` Pavel Emelyanov
2010-02-27 19:44 ` Eric W. Biederman
2010-02-28 22:05 ` Daniel Lezcano
2010-03-01 19:24 ` Eric W. Biederman
2010-03-01 21:42 ` Eric W. Biederman
2010-03-02 13:10 ` Cedric Le Goater
2010-03-02 15:03 ` Pavel Emelyanov
2010-03-02 15:14 ` Jan Engelhardt
2010-03-02 21:45 ` Eric W. Biederman
2010-03-02 21:19 ` Sukadev Bhattiprolu
2010-03-02 22:13 ` Eric W. Biederman
2010-03-03 0:07 ` Sukadev Bhattiprolu
2010-03-03 0:46 ` Eric W. Biederman
2010-03-03 15:38 ` Serge E. Hallyn
2010-03-03 19:47 ` Eric W. Biederman
2010-03-04 21:45 ` Eric W. Biederman
2010-03-04 22:55 ` Jan Engelhardt
2010-03-03 16:50 ` Pavel Emelyanov
2010-03-03 20:16 ` Eric W. Biederman
2010-03-05 19:18 ` Pavel Emelyanov
2010-03-05 20:26 ` Eric W. Biederman
2010-03-06 14:47 ` Daniel Lezcano
[not found] ` <4B926B1B.5070207-GANU6spQydw@public.gmane.org>
2010-03-06 20:48 ` Eric W. Biederman
[not found] ` <m1aaulyy5c.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-03-06 21:26 ` Daniel Lezcano
2010-03-08 8:32 ` Eric W. Biederman
2010-03-08 16:54 ` Daniel Lezcano
2010-03-08 17:29 ` Eric W. Biederman
2010-03-08 19:57 ` Daniel Lezcano
2010-03-08 20:24 ` Eric W. Biederman
2010-03-08 20:42 ` Daniel Lezcano
2010-03-08 20:47 ` Eric W. Biederman
2010-03-08 21:12 ` Daniel Lezcano
2010-03-08 21:25 ` Eric W. Biederman
2010-03-08 21:49 ` Serge E. Hallyn
2010-03-08 22:24 ` Eric W. Biederman
2010-03-09 10:03 ` Daniel Lezcano
2010-03-09 10:13 ` Eric W. Biederman
2010-03-09 10:26 ` Daniel Lezcano
2010-03-10 21:16 ` Daniel Lezcano
2010-03-08 17:07 ` Serge E. Hallyn
2010-03-08 17:35 ` Eric W. Biederman [this message]
2010-03-08 17:47 ` Serge E. Hallyn
2010-03-03 20:59 ` Oren Laadan
2010-03-03 21:05 ` Eric W. Biederman
[not found] ` <m1bpfbwuze.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2010-02-26 21:35 ` Pavel Emelyanov
2010-02-26 21:49 ` Eric W. Biederman
2010-02-23 23:49 ` RFC: netfilter: nf_conntrack: add support for "conntrack zones" Matt Helsley
2010-02-24 1:32 ` Eric W. Biederman
2010-02-24 1:39 ` Serge E. Hallyn
2010-01-14 18:32 ` Ben Greear
2010-01-15 15:03 ` jamal
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