Re: [PATCH 04/16] devpts: Teach /dev/ptmx to automount the appropriate devpts via path lookup

From: Eric W. Biederman
Date: Tue Apr 19 2016 - 14:57:07 EST

Jann Horn <jann@xxxxxxxxx> writes:

> On Fri, Apr 15, 2016 at 10:35:20AM -0500, Eric W. Biederman wrote:
>> +static inline bool is_dev_ptmx(struct inode *inode)
>> +{
>> + return inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR);
>> +}
> I'm not sure whether it matters, but I think a FUSE filesystem
> should be able to create a fake device that passes this check.
> fuse_init_inode() calls init_special_inode() with a user-supplied
> rdev for character devices. Is that a problem?

It isn't a problem with fuse, and I don't think it is a real problem
in general, but yes it would be good if that code had honored nodev
mount options.