On 24.10.2009 10:47, Anton Ivanov wrote:
> Following your logic we should all abandon directory permissions and
> stick to file-only ones. Hmm... Dunno, probably the blood level in my
> coffee subsystem is too high this morning, but I do not quite relish
> that idea.
>
I didn't affirm that. I only told, that directory permissions can't in fact
restrict access to the file it contains, they can only hamper accessing that
file via that directory.
On Sat, 2009-10-24 at 21:39 +0400, Dan Yefimov wrote:
> On 24.10.2009 20:59, Anton Ivanov wrote:
> >> Not to tell about
> >> that /proc/<PID>/fd/ contains only symbolic links, not files, so I can't
> >> understand, how the original reporter managed to gain access to the file in the
> >> restricted directory using that symlink.
> >
> > The perms are definitely broken and without a code audit on procfs I
> > would not bet that this is limited just to this rather obscure test
> > case.
On 24.10.2009 22:05, Anton Ivanov wrote:
> It works on Debian 2.6.26 out of the box. It is not an obscure patched
> kernel case I am afraid.
>
> If you redir an FD to a file using thus redir-ed FD in /proc allows you
> to bypass directory permissions for where the file is located.
> Thankfully, file permissions still apply so you need an app which has
> silly file perms in a bolted down directory for this.
>
> Symlinking the same file to a link on a normal ext3 or nfs filesystem as
On 24.10.2009 20:59, Anton Ivanov wrote:
>> Not to tell about
>> that /proc/<PID>/fd/ contains only symbolic links, not files, so I can't
>> understand, how the original reporter managed to gain access to the file in the
>> restricted directory using that symlink.
>
> The perms are definitely broken and without a code audit on procfs I
> would not bet that this is limited just to this rather obscure test
> case.
>
