From: Josh Steadmon <steadmon@google.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] remote-curl: die on server-side errors
Date: Tue, 13 Nov 2018 14:25:40 -0800 [thread overview]
Message-ID: <20181113222540.GE126896@google.com> (raw)
In-Reply-To: <20181113142624.GA17128@sigill.intra.peff.net>
On 2018.11.13 09:26, Jeff King wrote:
> On Mon, Nov 12, 2018 at 02:44:56PM -0800, steadmon@google.com wrote:
>
> > When a smart HTTP server sends an error message via pkt-line,
> > remote-curl will fail to detect the error (which usually results in
> > incorrectly falling back to dumb-HTTP mode).
> >
> > This patch adds a check in discover_refs() for server-side error
> > messages, as well as a test case for this issue.
>
> Aside from the reformatting of the conditional that Junio mentioned,
> this seems pretty good to me. But while looking at that, I found a few
> things, some old and some new. :)
>
> > diff --git a/remote-curl.c b/remote-curl.c
> > index 762a55a75f..bb3a86505e 100644
> > --- a/remote-curl.c
> > +++ b/remote-curl.c
> > @@ -436,7 +436,9 @@ static struct discovery *discover_refs(const char *service, int for_push)
> > } else if (maybe_smart &&
> > last->len > 5 && starts_with(last->buf + 4, "version 2")) {
> > last->proto_git = 1;
> > - }
> > + } else if (maybe_smart && last->len > 5 &&
> > + starts_with(last->buf + 4, "ERR "))
> > + die(_("remote error: %s"), last->buf + 8);
>
> The magic "4" here and in the existing "version 2" check is because we
> are expecting pkt-lines. The original conditional always calls
> packed_read_line_buf() and will complain if we didn't actually get a
> pkt-line.
>
> Should we confirm that we got a real packet-line? Or at least that those
> first four are even plausible hex chars?
>
> I admit that it's pretty unlikely that the server is going to fool us
> here. It would need something like "foo ERRORS ARE FUN!". And even then
> we'd report an error (whereas the correct behavior is falling back to
> dumb http, but we know that won't work anyway because that's not a valid
> ref advertisement). So I doubt this is really a bug per se, but it might
> make it easier to understand what's going on if we actually parsed the
> packet.
Unfortunately we can't just directly parse the data in last->buf,
because other parts of the code are expecting to see the raw pkt-line
data there. I tried adding a duplicate pointer and length variable for
this data and parsing that through packet_read_line_buf(), but even
without using the results this apparently has side-effects that break
all of t5550 (and probably other tests as well). It also fails if I
completely duplicate last->buf into a new char* and call
packet_readline_buf() on that, so there's clearly some interaction in
the pkt-line guts that I'm not properly accounting for.
> Similarly, we seem eager to accept "version 2" even if we are only
> expecting v0. I know you have another series working in that direction,
> but I don't think it touches this "proto_git". I guess accepting
> "version 2" as "we're speaking git protocol" and then barfing later with
> "wait, I didn't mean to speak v2" is probably OK.
>
> -Peff
next prev parent reply other threads:[~2018-11-13 22:25 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-12 22:44 [PATCH] remote-curl: die on server-side errors steadmon
2018-11-12 22:55 ` Stefan Beller
2018-11-13 2:52 ` Junio C Hamano
2018-11-13 3:02 ` Junio C Hamano
2018-11-13 22:15 ` Josh Steadmon
2018-11-13 14:26 ` Jeff King
2018-11-13 22:25 ` Josh Steadmon [this message]
2018-11-14 0:49 ` Jeff King
2018-11-14 7:00 ` Jeff King
2018-11-15 21:51 ` Josh Steadmon
2018-11-16 8:44 ` [PATCH 0/3] remote-curl smart-http discovery cleanup Jeff King
2018-11-16 8:47 ` [PATCH 1/3] remote-curl: refactor smart-http discovery Jeff King
2018-11-16 20:27 ` Josh Steadmon
2019-02-05 23:29 ` Junio C Hamano
2019-02-06 19:16 ` Jeff King
2019-02-06 19:18 ` Jeff King
2019-02-06 19:29 ` Josh Steadmon
2019-02-06 20:42 ` Junio C Hamano
2019-02-06 21:14 ` Jeff King
2019-02-06 19:18 ` [PATCH 2/3] remote-curl: tighten "version 2" check for smart-http Jeff King
2019-02-06 19:19 ` [PATCH 3/3] t5551: test server-side ERR packet Jeff King
2019-02-06 22:19 ` [PATCH 1/3] remote-curl: refactor smart-http discovery Junio C Hamano
2018-11-16 8:48 ` [PATCH 2/3] remote-curl: tighten "version 2" check for smart-http Jeff King
2018-11-16 20:28 ` Josh Steadmon
2018-11-16 8:49 ` [PATCH 3/3] remote-curl: die on server-side errors Jeff King
2018-11-16 20:04 ` [PATCH 0/3] remote-curl smart-http discovery cleanup Josh Steadmon
2018-12-12 0:25 ` [PATCH v3 0/4] Unify pkt-line error handling and refactor smart-http Josh Steadmon
2018-12-12 0:25 ` [PATCH v3 1/4] pack-protocol.txt: accept error packets in any context Josh Steadmon
2018-12-12 11:02 ` Jeff King
2018-12-13 1:17 ` Masaya Suzuki
2018-12-13 8:04 ` Jeff King
2018-12-13 22:18 ` Josh Steadmon
2018-12-17 21:33 ` Jeff King
2018-12-19 23:30 ` Josh Steadmon
2018-12-20 15:49 ` Jeff King
2018-12-12 0:25 ` [PATCH v3 2/4] remote-curl: refactor smart-http discovery Josh Steadmon
2018-12-12 0:25 ` [PATCH v3 3/4] remote-curl: tighten "version 2" check for smart-http Josh Steadmon
2018-12-12 0:25 ` [PATCH v3 4/4] lib-httpd, t5551: check server-side HTTP errors Josh Steadmon
2018-12-12 8:43 ` [PATCH v3 0/4] Unify pkt-line error handling and refactor smart-http Junio C Hamano
2018-11-13 14:30 ` [PATCH] remote-curl: die on server-side errors Junio C Hamano
2018-11-13 22:28 ` Josh Steadmon
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