Date: Sun, 27 Sep 2020 14:07:33 -0500 From: Kyle Evans <kevans@freebsd.org> To: Warner Losh <imp@bsdimp.com> Cc: Yuri <yuri@rawbw.com>, Freebsd hackers list <freebsd-hackers@freebsd.org> Subject: Re: Is it possible to exit the chroot(2) environment? Message-ID: <CACNAnaFVg2yZnWbfC=MmPfQ==XZYssHFuz%2BCjz%2B67TkZ108qRA@mail.gmail.com> In-Reply-To: <CANCZdfqJ14-Cpvi9%2Bd%2BHRgWbHk7vDUNNOKLUVOC9iBUqZKX=Pw@mail.gmail.com> References: <b6412618-02ec-1dbd-f474-b4412d7b774b@rawbw.com> <CANCZdfqJ14-Cpvi9%2Bd%2BHRgWbHk7vDUNNOKLUVOC9iBUqZKX=Pw@mail.gmail.com>
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On Sun, Sep 27, 2020 at 2:03 PM Warner Losh <imp@bsdimp.com> wrote: > > 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? > I'm almost certain they just aren't restricting you from chrooting to a directory out of the chroot if you have a reference to it, so it probably does something like: chdir("/"); chroot("/some/root"); /* Do stuff, but never chdir */ chroot("."); /* Working directory is still the real root. */ Thanks, Kyle Evans
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