Re: [PATCH] vfs: new O_NODE open flag

Jamie Lokier
2009-09-28T14:10:25Z

Miklos Szeredi wrote:
> > Hmm. I have just tried, and you _can _use open("/proc/self/fd/%d",
> > O_RDWR) to re-open with more permissions when you can't access the
> > path which /proc/self/fd/%d pretends to link to. It looks a bit
> > dubious, as you might have been passed an O_RDONLY descriptor with the
> > intention that you can't write to it... Oh well!
>
> True, /proc gives you access to the underlying "path" of an open file
> descriptor. If you don't want that, don't mount /proc in your limited
> namespace.

I wasn't using a limited namespace.

Just a directory without permission to be searched, and as a regular
user - which is historically supposed to prevent you from opening
files in it.

-- Jamie