On Mon 2009-10-26 13:57:49, Trond Myklebust wrote: > On Mon, 2009-10-26 at 18:46 +0100, Jan Kara wrote: > > That's what I'd think as well but it does not as I've just learned and > > tested :) proc_pid_follow_link actually directly gives a dentry of the > > target file without checking permissions on the way. It is weider. That symlink even has permissions. Those are not checked, either. > I seem to remember that is deliberate, the point being that a symlink > in /proc/*/fd/ may contain a path that refers to a private namespace. Well, it is unexpected and mild security hole. Part of the problem is that even if you have read-only filedescriptor, you can upgrade it to read-write, even if path is inaccessible to you. So if someone passes you read-only filedescriptor, you can still write to it. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
