linux-kernel - Re: [PATCH] orangefs: fix namespace handling

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Date:	Sat, 25 Jun 2016 19:03:12 -0400
From:	Mike Marshall <hubcap@...ibond.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Jann Horn <jannh@...gle.com>, LKML <linux-kernel@...r.kernel.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>, jann@...jh.net
Subject: Re: [PATCH] orangefs: fix namespace handling

Your suggestions make sense to me, especially after looking
at how other filesystems use init_user_ns...

As far as kicking us out of the Kernel, good grief, I hope not, it
was hard getting into the kernel!

-Mike

On Sat, Jun 25, 2016 at 12:29 AM, Eric W. Biederman
<ebiederm@...ssion.com> wrote:
> Jann Horn <jannh@...gle.com> writes:
>
>> diff --git a/fs/orangefs/devorangefs-req.c b/fs/orangefs/devorangefs-req.c
>> index db170be..a287a66 100644
>> --- a/fs/orangefs/devorangefs-req.c
>> +++ b/fs/orangefs/devorangefs-req.c
>> @@ -116,6 +116,13 @@ static int orangefs_devreq_open(struct inode *inode, struct file *file)
>>  {
>>       int ret = -EINVAL;
>>
>> +     /* in order to ensure that the filesystem driver sees correct UIDs */
>> +     if (file->f_cred->user_ns != &init_user_ns) {
>> +             gossip_err("%s: device cannot be opened outside init_user_ns\n",
>> +                        __func__);
>> +             goto out;
>> +     }
>> +
>
> Not necessarily in this patch but the code should also verify that the
> opener is also in the initial pid namespace as pids are transferred in
> the upcalls as well.
>
>>       if (!(file->f_flags & O_NONBLOCK)) {
>>               gossip_err("%s: device cannot be opened in blocking mode\n",
>>                          __func__);
>
> Eric