issue with unsetting 'arch' flag

[Garrett Cooper]

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

    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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