Re: [PATCH RFC 01/12] userns: Support 9p interacting with multiple user namespaces

[ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)]

Zhao Hongjiang <zhaohongjiang37-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:

> On 2012/11/20 20:43, Eric W. Biederman wrote:
>> From: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
>
>> diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
>> index d934f04..1c750ab 100644
>> --- a/fs/9p/v9fs.c
>> +++ b/fs/9p/v9fs.c
>> @@ -161,7 +161,13 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
>>  				ret = r;
>>  				continue;
>>  			}
>> -			v9ses->dfltuid = option;
>> +			v9ses->dfltuid = make_kuid(&init_user_ns, option);
>
> I think the init_user_ns should be current_user_ns() cause the value is come from userspace
> and in kernel we should mapping it to its own user_ns.

Good point.  current_user_ns() is more appropriate and maintainable.

For now you can only mount 9p when current_user_ns() == &init_user_ns
but that might change in the future.

Thanks,
Eric