From: "brian m. carlson" <sandals@crustytoothpaste.net>
To: Alex Waite <alex@waite.eu>
Cc: git@vger.kernel.org
Subject: Re: [BUG] credential wildcard does not match hostnames containing an underscore
Date: Tue, 12 Oct 2021 21:12:28 +0000 [thread overview]
Message-ID: <YWX6PJrjgp6rHZu/@camp.crustytoothpaste.net> (raw)
In-Reply-To: <28ff3572-1819-4e27-a46d-358eddd46e45@www.fastmail.com>
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On 2021-10-12 at 14:25:04, Alex Waite wrote:
> What did you do before the bug happened? (Steps to reproduce your issue)
>
> I configured my ~/.gitconfig so that git credentials invoke a helper for a
> subdomain using wildcards. For example:
>
> [credential "https://*.example.com"]
> helper = "/usr/local/bin/custom_helper"
>
> This works for all tested subdomains /except/ for those which contain an
> underscore.
>
> authenticates without prompting:
> git clone https://testA.example.com
> git clone https://test-b.example.com
>
> prompts for authentication:
> git clone https://test_c.example.com
>
>
> What did you expect to happen? (Expected behavior)
>
> I expected the pattern matching to work for all resolved URLs.
As mentioned below and elsewhere in this thread, this isn't a valid
hostname, and as a result, this isn't even a valid URL according to RFC
3986 unless you intended it to be resolved in a system other than DNS.
I don't personally see a reason to accept locally specified hostnames
(e.g., in a hosts file) which don't conform to RFC 1123 or which
otherwise don't conform to the DNS standards for hostnames, but perhaps
others can see a good reason to do so.
> Anything else you want to add:
>
> If I don't use pattern matching, and instead state the URL explicitly in
> ~/.gitconfig, it works as expected. For example, the following works:
>
> [credential "https://test_c.example.com"]
> helper = "/usr/local/bin/custom_helper"
>
> As part of writing this bug report, I learned that underscores are not valid
> DNS characters for hostnames (but are valid for other record types, which are
> largely irrelevant to git).
>
> What is notable is that git pattern matching enforces the spec more strictly
> than without pattern matching (and more strictly than the OS and every DNS
> server between my system and the authoritative DNS server).
>
> At minimum, git should be consistent with itself.
>
> As for which behavior is "correct", the question is whether git wishes to
> follow/enforce the spec tightly, or not get in the way of a real-world oddity
> that everything else seems to tolerate.
There are a variety of systems which won't accept such a hostname, so I
think at best we should reject such hostnames altogether and prevent
this from working at all, since they are likely to be subtly broken in a
variety of ways and we won't want to try to fix all of the cases in
which things are broken. To me, this appears to be simply a case where
we should improve error handling.
--
brian m. carlson (he/him or they/them)
Toronto, Ontario, CA
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prev parent reply other threads:[~2021-10-12 21:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-12 14:25 [BUG] credential wildcard does not match hostnames containing an underscore Alex Waite
2021-10-12 17:47 ` Junio C Hamano
2021-10-12 18:00 ` Alex Waite
2021-10-12 18:28 ` Junio C Hamano
2021-10-12 20:45 ` Jeff King
2021-10-12 20:42 ` Jeff King
2021-10-12 20:53 ` Jeff King
2021-10-12 21:12 ` [PATCH] urlmatch: add underscore to URL_HOST_CHARS Jeff King
2021-10-12 21:21 ` [BUG] credential wildcard does not match hostnames containing an underscore brian m. carlson
2021-10-12 21:32 ` Jeff King
2021-10-12 21:48 ` brian m. carlson
2021-10-12 21:55 ` Jeff King
2021-10-12 21:57 ` brian m. carlson
2021-10-12 22:25 ` Aaron Schrab
2021-10-13 16:21 ` Alex Waite
2021-10-14 11:43 ` Philip Oakley
2021-10-12 21:12 ` brian m. carlson [this message]
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