From: ebiederm@xmission•com (Eric W. Biederman)
To: Daniel Lezcano <daniel.lezcano@free•fr>
Cc: Pavel Emelyanov <xemul@parallels•com>,
Sukadev Bhattiprolu <sukadev@linux•vnet.ibm.com>,
Serge Hallyn <serue@us•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: Tue, 09 Mar 2010 02:13:08 -0800 [thread overview]
Message-ID: <m1ocixn6q3.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <4B961D09.4010802@free.fr> (Daniel Lezcano's message of "Tue\, 09 Mar 2010 11\:03\:53 +0100")
Daniel Lezcano <daniel.lezcano@free•fr> writes:
> Eric W. Biederman wrote:
>
> [ ... ]
>> I guess my meaning is I was expecting.
>> child = fork();
>> if (child == 0) {
>> execve(...);
>> }
>> waitpid(child);
>>
>> This puts /bin/sh in the container as well.
>>
> #include <unistd.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <syscall.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <sys/param.h>
>
> #define __NR_setns 300
>
> int setns(int nstype, int fd)
> {
> return syscall (__NR_setns, nstype, fd);
> }
>
> int main(int argc, char *argv[])
> {
> char path[MAXPATHLEN];
> char *ns[] = { "pid", "mnt", "net", "pid", "uts" };
> const int size = sizeof(ns) / sizeof(char *);
> int fd[size];
> int i;
> pid_t pid;
> if (argc != 3) {
> fprintf(stderr, "mynsenter <pid> <command>\n");
> exit(1);
> }
>
> for (i = 0; i < size; i++) {
> sprintf(path, "/proc/%s/ns/%s", argv[1], ns[i]);
>
> fd[i] = open(path, O_RDONLY| FD_CLOEXEC);
> if (fd[i] < 0) {
> perror("open");
> return -1;
> }
>
> }
> for (i = 0; i < size; i++)
> if (setns(0, fd[i])) {
> perror("setns");
> return -1;
> }
>
> pid = fork();
> if (!pid) {
>
> fprintf(stderr, "mypid is %d\n", syscall(__NR_getpid));
>
> execve(argv[2], &argv[2], NULL);
> perror("execve");
>
> }
>
> if (pid < 0) {
> perror("fork");
> return -1;
> }
>
> if (waitpid(&pid, NULL, 0) < 0) {
> perror("waitpid");
> }
>
> return 0;
> }
&pid ??? Isn't that a type error?
> Waitpid returns an error:
>
> waitpid: No child processes
>
> The pid number returned by fork is the pid from the init pid namespace but it
> seems waitpid is waiting for a pid belonging to the child pid namespace.
>
> waitpid
> -> wait4
> -> find_get_pid
> -> find_vpid
> -> find_pid_ns(nr, current->nsproxy->pid_ns);
But it isn't. It is.
find_pid_ns(nr, task_active_pid_ns(current));
Which is:
find_pid_ns(nr, ns_of_pid(task_pid(current)));
Which is a value that doesn't change. When we attach to a pid namespace.
> The current->nsproxy->pid_ns is the one of the namespace we attached to. So the
> real pid returned by the fork does not exist in this pid namespace.
> Maybe fork should return a pid number belonging to the current pid namespace we
> are attached no ?
Do you not have my patch that changed that?
Eric
next prev parent reply other threads:[~2010-03-09 10:13 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 [this message]
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
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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