From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: Thomas Braun <thomas.braun@virtuell-zuhause.de>,
Duy Nguyen <pclouds@gmail.com>,
Junio C Hamano <gitster@pobox.com>,
Jeffrey Walton <noloader@gmail.com>,
Todd Zullinger <tmz@pobox.com>, Git List <git@vger.kernel.org>,
Marc Stevens <marc@marc-stevens.nl>
Subject: Re: disabling sha1dc unaligned access, was Re: One failed self test on Fedora 29
Date: Tue, 12 Mar 2019 17:01:25 -0400 [thread overview]
Message-ID: <20190312210124.GA5025@sigill.intra.peff.net> (raw)
In-Reply-To: <87y35kb8ft.fsf@evledraar.gmail.com>
On Tue, Mar 12, 2019 at 01:09:42PM +0100, Ævar Arnfjörð Bjarmason wrote:
> > To be clear, I do sympathize with the notion that not pulling things
> > in-tree keeps our relationship with upstream more disciplined, and that
> > has value. I'm just not altogether clear how much it's really hurt us
> > overall to be undisciplined.
>
> I agree that say the compat/regex divergence hasn't hurt us much if at
> all. Just that we have a few conflicting desires:
>
> A. Make sure you can "make" git by default without pulling down a bunch
> of libraries, especially if they're not ubiquitous. Thus shipping
> the likes of sha1dc.
>
> B. Being able to hotfix those libraries.
>
> C. Upstreaming those hotfixes when they happen.
>
> D. Updating the library we pulled in due to "A" from upstream.
>
> In practice because we've wanted "A" we've felt the need to do "B", but
> then also not "C" without ever having the discussion that skipping that
> part was a good idea, and as a result "D" is hard.
>
> Do we urgently need "D"? No. I'm just pointing out that in addition to
> optimzing for "B" being easy we should also weigh being good free
> software citizens and coordinate fixes with upstream, which also makes a
> future "D" easier.
Yeah, I think your mental model there makes some sense.
> Also, while I don't know of any bugs in compat/regex. I think it's a bit
> concerning that we're carrying 2010-era code for something like the
> regex engine that we expose e.g. over gitweb.
TBH, I think it's probably a bad idea to open any version of that code
to untrusted people, because it's easy to write a DoS regex against it.
There are libraries (like re2) that would be a better fit (I seem to
recall that there may be some DFA-only support in pcre, too, but I
haven't looked at it in a long time; if there is, it might be a sane
gitweb feature to only expose that engine).
-Peff
next prev parent reply other threads:[~2019-03-12 21:01 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-08 10:48 One failed self test on Fedora 29 Jeffrey Walton
2019-03-08 17:43 ` Todd Zullinger
2019-03-09 12:34 ` Jeffrey Walton
2019-03-09 13:12 ` Jeffrey Walton
2019-03-11 2:00 ` Junio C Hamano
2019-03-11 2:16 ` Jeffrey Walton
2019-03-11 3:37 ` disabling sha1dc unaligned access, was " Jeff King
2019-03-11 10:40 ` Jeffrey Walton
2019-03-11 18:19 ` Jeff King
2019-03-11 11:58 ` Duy Nguyen
2019-03-11 18:15 ` Thomas Braun
2019-03-11 18:23 ` Jeff King
2019-03-12 7:27 ` Junio C Hamano
2019-03-12 10:51 ` Jeff King
2019-03-13 11:47 ` Thomas Braun
2019-03-13 15:39 ` Jeff King
2019-03-13 16:00 ` Ævar Arnfjörð Bjarmason
2019-03-12 8:53 ` Ævar Arnfjörð Bjarmason
2019-03-12 11:05 ` Jeff King
2019-03-12 12:09 ` Ævar Arnfjörð Bjarmason
2019-03-12 21:01 ` Jeff King [this message]
2019-03-12 21:06 ` [PATCH] Makefile: fix unaligned loads in sha1dc with UBSan Jeff King
2019-03-12 21:17 ` Ævar Arnfjörð Bjarmason
2019-03-12 21:19 ` Jeff King
2019-03-11 3:29 ` One failed self test on Fedora 29 Jeff King
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