From: Brandon Williams <bmwill@google.com>
To: Jeff King <peff@peff.net>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: bw/transport-protocol-policy
Date: Thu, 1 Dec 2016 11:35:24 -0800 [thread overview]
Message-ID: <20161201193524.GC54082@google.com> (raw)
In-Reply-To: <20161201192055.44mtvtacyhpbqbqu@sigill.intra.peff.net>
On 12/01, Jeff King wrote:
> On Thu, Dec 01, 2016 at 10:14:15AM -0800, Brandon Williams wrote:
>
> > > 1. The new policy config lets you say "only allow this protocol when
> > > the user specifies it". But when http.c calls is_transport_allowed(),
> > > the latter has no idea that we are asking it about potential
> > > redirects (which obviously do _not_ come from the user), and would
> > > erroneously allow them.
> > >
> > > I think this needs fixed before the topic is merged. It's not a
> > > regression, as it only comes into play if you use the new policy
> > > config. But it is a minor security hole in the new feature.
> >
> > I agree and it should be an easy fix. We can just add a parameter like
> > so:
> >
> > diff --git a/transport.c b/transport.c
> > index 2c0ec76..d38d50f 100644
> > --- a/transport.c
> > +++ b/transport.c
> > @@ -723,7 +723,7 @@ static enum protocol_allow_config get_protocol_config(const char *type)
> > return PROTOCOL_ALLOW_USER_ONLY;
> > }
> >
> > -int is_transport_allowed(const char *type)
> > +int is_transport_allowed(const char *type, int redirect)
> > {
> > const struct string_list *whitelist = protocol_whitelist();
> > if (whitelist)
> > @@ -735,7 +735,7 @@ int is_transport_allowed(const char *type)
> > case PROTOCOL_ALLOW_NEVER:
> > return 0;
> > case PROTOCOL_ALLOW_USER_ONLY:
> > - return git_env_bool("GIT_PROTOCOL_FROM_USER", 1);
> > + return git_env_bool("GIT_PROTOCOL_FROM_USER", !redirect);
> > }
> >
> > die("BUG: invalid protocol_allow_config type");
> >
> > That way the libcurl code can say it is asking if it is ok to redirect
> > to that protocol.
>
> I wouldn't expect anyone to ever set GIT_PROTOCOL_FROM_USER=1, but it
> does behave in a funny way here, overriding the "redirect" flag. I think
> we'd want something more like:
>
> if (redirect < 0)
> redirect = git_env_bool("GIT_PROTOCOL_FROM_USER", 1);
>
> and then pass in "-1" from transport_check_allowed().
I don't think I quite follow your solution but I came up with this:
case PROTOCOL_ALLOW_USER_ONLY:
return redirect ? 0 : git_env_bool("GIT_PROTOCOL_FROM_USER", 1);
Which should address the same issue.
--
Brandon Williams
next prev parent reply other threads:[~2016-12-01 19:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-29 0:15 What's cooking in git.git (Nov 2016, #06; Mon, 28) Junio C Hamano
2016-11-29 1:05 ` Brandon Williams
2016-11-29 6:37 ` Jeff King
2016-11-29 6:51 ` Jeff King
2016-11-30 19:54 ` Brandon Williams
2016-11-30 23:28 ` Brandon Williams
2016-11-30 23:32 ` Jeff King
2016-11-30 23:40 ` Jeff King
2016-11-30 23:42 ` Brandon Williams
2016-11-30 23:46 ` Jeff King
2016-11-30 23:57 ` Brandon Williams
2016-11-30 23:59 ` Jeff King
2016-12-01 0:04 ` Jeff King
2016-12-01 0:08 ` Brandon Williams
2016-12-01 0:14 ` Stefan Beller
2016-12-01 1:14 ` Brandon Williams
2016-12-01 0:06 ` Brandon Williams
2016-12-01 0:19 ` Jeff King
2016-11-30 23:43 ` Stefan Beller
2016-12-01 7:09 ` Johannes Sixt
2016-12-01 7:19 ` Jeff King
2016-11-29 6:59 ` Jeff King
2016-11-29 18:31 ` Junio C Hamano
2016-11-29 18:37 ` Jeff King
2016-11-29 19:21 ` Stefan Beller
2016-11-29 19:26 ` Junio C Hamano
2016-11-29 19:29 ` Stefan Beller
2016-11-30 0:25 ` Stefan Beller
2016-12-01 8:30 ` bw/transport-protocol-policy Jeff King
2016-12-01 18:14 ` bw/transport-protocol-policy Brandon Williams
2016-12-01 19:20 ` bw/transport-protocol-policy Jeff King
2016-12-01 19:35 ` Brandon Williams [this message]
2016-12-01 19:46 ` bw/transport-protocol-policy Jeff King
2016-12-01 19:53 ` bw/transport-protocol-policy Brandon Williams
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