Re: [PATCH RESEND v2 16/18] fuse: Support fuse filesystems outside of init_user_ns

Miklos Szeredi
2016-03-09T14:48:22Z

On Wed, Mar 9, 2016 at 3:18 PM, Seth Forshee <seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> wrote:
> On Wed, Mar 09, 2016 at 12:29:23PM +0100, Miklos Szeredi wrote:
>> On Mon, Jan 04, 2016 at 12:03:55PM -0600, Seth Forshee wrote:

>> > -static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
>> > +static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
>> > + struct user_namespace *user_ns)
>> > {
>> > char *p;
>> > memset(d, 0, sizeof(struct fuse_mount_data));
>> > d->max_read = ~0;
>> > d->blksize = FUSE_DEFAULT_BLKSIZE;
>> > + d->user_id = make_kuid(user_ns, 0);
>> > + d->group_id = make_kgid(user_ns, 0);
>>
>> It is true that if "user_id=" or "group_id" options were omitted we used the
>> zero uid/gid values. However, this isn't actually used by anybody AFAIK, and
>> generalizing it for userns doesn't seem to make much sense.
>>
>> So I suggest we that we instead return an error if mounting from a userns AND
>> neither "allow_other" nor both "user_id" and "group_id" are specified.
>
> But those are also used for ownership of the connection files in
> fusectl. In an allow_other mount shouldn't those files by owned by
> namespace root and not global root?

Yes.

Can't we use current_cred()->uid/gid? Or fsuid/fsgid maybe?

When we have true unprivileged mounts, the user_id/group_id options
become redundant anyway and we can just use the current credentials.

Thanks,
Miklos

------------------------------------------------------------------------------
Transform Data into Opportunity.
Accelerate data analysis in your applications with
Intel Data Analytics Acceleration Library.
Click to learn more.
http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140
--
fuse-devel mailing list
To unsubscribe or subscribe, visit https://lists.sourceforge.net/lists/listinfo/fuse-devel