Re: [devel] [PATCH hasher-priv v1 0/3] Make a daemon from the hasher-priv

[Arseny Maslennikov <arseny@altlinux.org>]

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On Thu, Oct 01, 2020 at 10:01:29PM +0200, Alexey Gladkov wrote:
> On Thu, Oct 01, 2020 at 08:44:00PM +0300, Arseny Maslennikov wrote:
> > On Thu, Oct 01, 2020 at 07:21:11PM +0200, Alexey Gladkov wrote:
> > > On Thu, Sep 17, 2020 at 04:09:35PM +0300, Arseny Maslennikov wrote:
> > > > On Fri, Dec 13, 2019 at 12:42:02PM +0100, Alex Gladkov wrote:
> > > > > From: Alexey Gladkov <legion@altlinux.org>
> > > > > 
> > > > > The hasher-priv is a SUID utility. This is not good. Separation of the
> > > > > server and client parts will allow us to remove SUID flag.
> > > > > 
> > > > > The separation of server and client is not intended to give clients
> > > > > access over the network. This separation is only necessary to distinguish
> > > > > privileges. Only UNIX domain socket is used.
> > > > > 
> > > > > A separate session process is created for each connected user. Each such
> > > > > process ends after a certain period of inactivity.
> > > > 
> > > > Thank you for trying this idea out; despite the trolling attempts, this
> > > > effort is long welcome.
> > > 
> > > I created this patchset a long time ago. I've already lost my context. It
> > > might be better if you keep working on this patch.
> > > 
> > 
> > Great! I'd like to work on this further.
> 
> You have asked many questions. I didn’t answer everything because these
> patches are already 5 years old and I can hardly remember what I had in my
> head when I did them. Submitting patches to the mailing list was the
> second attempt to upstream them. Actually, I was afraid of losing them
> altogether, so I merged some of the patches. Originally I had about 10
> patches in a patchset.
> 
> I'm not sure if I have time for this rework. But we can try.

So, I guess you won't mind if I would prepare a v2 which fixes some of
the issues discussed, based on my repo. We're in no hurry, since Dmitry
is currently away for the next couple of weeks.

> We can
> discuss the hasher-privd in russian if you like :)

I'm personally fine with both english and russian; looks like you're too.
The remaining concerns are:
* if everyone else interested can respond and continue the conversation
* if the community around hasher ever goes international.

I responded in english, since the patch messages were in english, and in
that case I usually take the (nowadays rare with covid) opportunity to
practice. Если же то, на что я отвечаю, пишут по-русски, то и отвечать,
наверное, следует тоже по-русски.

Если вдруг чувствуете, что лучше по-русски, можете на русский переключаться.

Ну и иногда пишешь что-то по-русски в некоторый
профессионально-технический разговор, а в реплике столько оказывается
непереводных терминов и собственных имён, что уж лучше по-английски бы писал. :)

> 
> > > > There are some issues with the patchset, which I intend to cover in
> > > > subsequent emails. I have published[1] some fix-up commits on top of
> > > > these patches in an attempt to ensure that, barring the issues with a
> > > > known fix, this works; however, some bugs are definitely still unsolved
> > > > by now, so I decided to discuss the more apparent points first.
> > > > 
> > > > [1] http://git.altlinux.org/people/arseny/packages/hasher-priv.git?a=summary
> > > 
> > > It looks like you've already started working on finalizing this patch :)
> > > 
> > > > There's an issue when hasher-privd tries to fulfill a chrootuid{1,2}
> > > > request: the (eventually) unprivileged task executor process
> > > > successfully invokes waitpid() or the likes on a child process,
> > > > select()s on I/O descriptors, but gets CHLD later — and it looks like
> > > > the inherited signal handler causes it to wait again.
> > > 
> > > Hm...
> > > 
> > > > I've not yet found a decent reproducer — the following command:
> > > > `hsh-shell $workdir'
> > > 
> > > There is no such command. You need to send command to run /bin/sh.
> > 
> > Yes, there's no such IPC command, I was referring to a shell command run
> > in the host system by the caller user.
> > 
> > > 
> > > > reproduces the issue reliably for me, but hsh-mkchroot, hsh-rmchroot,
> > > > hsh-install are all OK. The root cause nevertheless is not yet
> > > > established. It looks like this has to be patched somewhere in
> > > > chrootuid(), but I might be wrong on this one.
> > > > 
> 
> 
> 
> -- 
> Rgrds, legion
> 



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