issue with unsetting 'arch' flag

[Alexander Best]

On Wed Oct  6 10, Garrett Cooper wrote:
> On Tue, Oct 5, 2010 at 4:50 PM, Alexander Best <arundel at freebsd.org> wrote:
> > hi there,
> >
> > i think the following example shows the problem better than a long explanation:
> >
> > `touch ftest && chflags arch ftest && chflags -vv 0 ftest`.
> >  ^^non-root     ^^root                ^^non-root
> >
> > chflags claims to have cleared the 'arch' flag (which should be impossible as
> > non-root user), but indeed has done nothing.
> >
> > i've tried the same with 'sappnd' and that works as can be expected.
> >
> > The issue was confirmed to exist in HEAD (me), stable/8 (pgollucc1, jpaetzel)
> > and stable/7 (nox).
> > On stable/6 it does NOT exist (jpaetzel). chflags properly fails with EPERM.
> 
>     Fails for me when I call the syscall directly, as I would expect,
> and passes when I'm superuser:
> 
> $ ./test_chflags
> (uid, euid) = (1000, 1000)
> test_chflags: chflags: Operation not permitted
> test_chflags: lchflags: Operation not permitted
> $ sudo ./test_chflags
> (uid, euid) = (0, 0)
> 
>     According to my basic inspection in strtofflags
> (.../lib/libc/gen/strtofflags.c), it works as well.
>     And last but not least, executing the commands directly on the CLI work:
> 
> $ tmpfile=`mktemp /tmp/chflags.XXXXXX`
> $ chflags arch $tmpfile
> chflags: /tmp/chflags.nQm1IL: Operation not permitted
> $ rm $tmpfile
> $ tmpfile=`mktemp /tmp/chflags.XXXXXX`
> $ sudo chflags arch $tmpfile
> $ sudo chflags noarch $tmpfile
> $ rm $tmpfile

thanks for your test app and helping out with this problem. i'm not sure
however you understood the problem. probably i didn't explain it right:

$ sudo rm -d /tmp/chflags.XXXXXX
$ tmpfile=`mktemp /tmp/chflags.XXXXXX`
$ sudo chflags arch $tmpfile
$ chflags noarch $tmpfile

is what's causing the problem. the last chflags call should fail, but it
doesn't.

cheers.
alex

> 
>     Your results may (but shouldn't) vary [unless your environment is
> setup differently]...
>     Please note that I'm using UFS2 with SUJ... not all filesystems
> support this (ext2/3/4? msdosfs? ZFS?), so I would be careful about
> which filesystem you pick and whether or not there's a bug where it's
> not properly identifying that the operation you're attempting to
> perform is valid.
> Thanks,
> -Garrett
> 
> $ uname -a
> FreeBSD bayonetta.local 9.0-CURRENT FreeBSD 9.0-CURRENT #9 r211309M:
> Thu Aug 19 22:50:36 PDT 2010
> root at bayonetta.local:/usr/obj/usr/src/sys/BAYONETTA  amd64



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