Date: Sun, 27 Sep 2020 13:02:54 -0600 From: Warner Losh <imp@bsdimp.com> To: Yuri <yuri@rawbw.com> Cc: Freebsd hackers list <freebsd-hackers@freebsd.org> Subject: Re: Is it possible to exit the chroot(2) environment? Message-ID: <CANCZdfqJ14-Cpvi9%2Bd%2BHRgWbHk7vDUNNOKLUVOC9iBUqZKX=Pw@mail.gmail.com> In-Reply-To: <b6412618-02ec-1dbd-f474-b4412d7b774b@rawbw.com> References: <b6412618-02ec-1dbd-f474-b4412d7b774b@rawbw.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, Sep 27, 2020 at 12:30 PM Yuri <yuri@rawbw.com> wrote: > This line > > https://github.com/rpm-software-management/rpm/blob/master/lib/rpmchroot.c#L155 > calls chroot(".") in order to exit from the chroot environment. > Interesting. FreeBSD doesn't allow that. > It apparently succeeds on Linux (this is rpm), but it fails on FreeBSD > with "Operation not permitted", while executed under sudo. > > The chroot(2) man page doesn't mention anything about exiting the chroot > environment. > True. Such behavior is undefined. There's no defined notion of exiting a chroot. It doesn't seem to be documented in the few examples of the chroot(2) call linux man pages I've found. Do you have documentation on what, exactly, it's supposed to do? Does chroot(2) behave differently on Linux and FreeBSD, and chroot(".") > is a valid way to exit on Linux and not on FreeBSD? Or what is going on > here? > Generally, one is not supposed to exit a chroot. :) Though jail(2) exists because it's trivially possible in most cases. I wish somebody familiar with chroot add this information into the > chroot(2) man page. > POSIX never defined the behavior (and it's been removed in newer versions of POSIX). Warner
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CANCZdfqJ14-Cpvi9%2Bd%2BHRgWbHk7vDUNNOKLUVOC9iBUqZKX=Pw>