From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org, Brandon Williams <bwilliamseng@gmail.com>,
Jonathan Tan <jonathantanmy@google.com>
Subject: Re: [PATCH 0/3] protocol v2 and hidden refs
Date: Tue, 11 Dec 2018 12:45:16 +0100 [thread overview]
Message-ID: <875zw0nv77.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <20181211104236.GA6899@sigill.intra.peff.net>
On Tue, Dec 11 2018, Jeff King wrote:
> When using the v2 protocol, hidden-ref config is not respected at all:
>
> $ git config transfer.hiderefs refs/tags/
> $ git -c protocol.version=0 ls-remote . | grep -c refs/tags
> 0
> $ git -c protocol.version=2 ls-remote . | grep -c refs/tags
> 1424
>
> The fix in patch 3 is pretty straightforward, but note:
>
> - I'm a little worried this may happen again with future features. The
> root cause is that "ls-refs" follows a different code path than the
> ref advertisement for "upload-pack". So if we add any new config,
> it needs to go both places (non ref-advertisement config is OK, as
> the v2 "fetch" command is a lot closer to a v0 upload-pack).
>
> I think this is just an issue for any future features. I looked for
> other existing features which might be missing in v2, but couldn't
> find any.
>
> I don't know if there's a good solution. I tried running the whole
> test suite with v2 as the default. It does find this bug, but it has
> a bunch of other problems (notably fetch-pack won't run as v2, but
> some other tests I think also depend on v0's reachability rules,
> which v2 is documented not to enforce).
I think a global test mode for it would be a very good idea.
> - The "serve" command is funky, because it has no concept of whether
> the "ls-refs" is for fetching or pushing. Is git-serve even a thing
> that we want to support going forward? I know part of the original
> v2 conception was that one would be able to just connect to
> "git-serve" and do a number of operations. But in practice the v2
> probing requires saying "I'd like to git-upload-pack, and v2 if you
> please". So no client ever calls git-serve.
>
> Is this something we plan to eventually move to? Or can it be
> considered a funny vestige of the development? In the latter case, I
> think we should consider removing it.
>
> I've worked around it here with patch 2, but note that "git serve"
> would not ever respect uploadpack.hiderefs nor receive.hiderefs
> (since it has no idea which operation it's doing).
>
> The patches are:
>
> [1/3]: serve: pass "config context" through to individual commands
> [2/3]: parse_hide_refs_config: handle NULL section
> [3/3]: upload-pack: support hidden refs with protocol v2
Does this issue rise to the level of needing a security point-release
(which I'm discussing here as the details are already public). The
transfer.hideRefs docs have said:
Even if you hide refs, a client may still be able to steal the
target objects via the techniques described in the "SECURITY"
section of the gitnamespaces(7) man page; it’s best to keep private
data in a separate repository.
So we never promised to hide the objects, but definitely promised to
hide the ref names. I don't know if anyone uses this in practice for
secret ref names, but if they do they have a data leak if they enable
protocol v2.
More importantly, the docs for receive.hideRefs say. "An attempt to
update or delete a hidden ref by git push is rejected.". It seems this
bit was enforced, i.e. this passes before and after your 3/3, but I have
not dug enough to be 100% satisfied with that.
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index ca69636fd5..20059c3308 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -210,6 +210,13 @@ test_expect_success 'protocol v2 supports hiderefs' '
! grep refs/tags actual
'
+test_expect_success 'protocol v2 respects hiderefs when pushing' '
+ git init --bare server.git &&
+ git -C server.git config transfer.hideRefs refs/tags &&
+ test_must_fail git -c protocol.version=0 push "file://$PWD/server.git" mark &&
+ test_must_fail git -c protocol.version=2 push "file://$PWD/server.git" mark
+'
+
test_expect_success 'ls-remote --symref' '
git fetch origin &&
cat >expect <<-EOF &&
If there's some bug where you can bypass this push protection that would
be much worse. E.g. GitLab uses "keep-around" refs to track its own
internal state, and it would be bad if users could manipulate it.
> builtin/upload-pack.c | 1 +
> ls-refs.c | 16 +++++++++++++++-
> ls-refs.h | 3 ++-
> refs.c | 3 ++-
> serve.c | 9 +++++----
> serve.h | 7 +++++++
> t/t5512-ls-remote.sh | 6 ++++++
> upload-pack.c | 4 ++--
> upload-pack.h | 4 ++--
> 9 files changed, 42 insertions(+), 11 deletions(-)
>
> -Peff
next prev parent reply other threads:[~2018-12-11 11:45 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 10:42 [PATCH 0/3] protocol v2 and hidden refs Jeff King
2018-12-11 10:43 ` [PATCH 1/3] serve: pass "config context" through to individual commands Jeff King
2018-12-14 2:09 ` Junio C Hamano
2018-12-14 8:20 ` Jeff King
2018-12-15 0:31 ` Junio C Hamano
2018-12-16 10:25 ` Jeff King
2018-12-16 11:12 ` Junio C Hamano
2018-12-18 12:47 ` Jeff King
2018-12-14 8:36 ` Jonathan Nieder
2018-12-14 8:55 ` Jeff King
2018-12-14 9:28 ` Jonathan Nieder
2018-12-14 9:55 ` Jeff King
2018-12-11 10:43 ` [PATCH 2/3] parse_hide_refs_config: handle NULL section Jeff King
2018-12-14 2:11 ` Junio C Hamano
2018-12-11 10:44 ` [PATCH 3/3] upload-pack: support hidden refs with protocol v2 Jeff King
2018-12-11 11:45 ` Ævar Arnfjörð Bjarmason [this message]
2018-12-11 13:55 ` [PATCH 0/3] protocol v2 and hidden refs Jeff King
2018-12-11 21:21 ` [PATCH 0/3] Add a GIT_TEST_PROTOCOL_VERSION=X test mode Ævar Arnfjörð Bjarmason
2018-12-11 21:24 ` Ævar Arnfjörð Bjarmason
2018-12-11 21:21 ` [PATCH 1/3] tests: add a special setup where for protocol.version Ævar Arnfjörð Bjarmason
2018-12-12 0:27 ` [PATCH 0/3] Some fixes and improvements Jonathan Tan
2018-12-12 0:27 ` [PATCH 1/3] squash this into your patch Jonathan Tan
2018-12-12 0:27 ` [PATCH 2/3] builtin/fetch-pack: support protocol version 2 Jonathan Tan
2018-12-12 0:27 ` [PATCH 3/3] also squash this into your patch Jonathan Tan
2018-12-13 2:49 ` [PATCH 0/3] Some fixes and improvements Junio C Hamano
2018-12-13 15:58 ` [PATCH v2 0/8] protocol v2 fixes Ævar Arnfjörð Bjarmason
2018-12-17 22:40 ` [PATCH v3 0/4] " Ævar Arnfjörð Bjarmason
2018-12-18 12:48 ` Jeff King
2018-12-17 22:40 ` [PATCH v3 1/4] serve: pass "config context" through to individual commands Ævar Arnfjörð Bjarmason
2018-12-17 22:40 ` [PATCH v3 2/4] parse_hide_refs_config: handle NULL section Ævar Arnfjörð Bjarmason
2018-12-17 22:40 ` [PATCH v3 3/4] upload-pack: support hidden refs with protocol v2 Ævar Arnfjörð Bjarmason
2018-12-17 22:40 ` [PATCH v3 4/4] fetch-pack: support protocol version 2 Ævar Arnfjörð Bjarmason
2019-01-08 19:45 ` Junio C Hamano
2019-01-08 20:38 ` Jonathan Tan
2019-01-08 21:14 ` Jeff King
2018-12-13 15:58 ` [PATCH v2 1/8] serve: pass "config context" through to individual commands Ævar Arnfjörð Bjarmason
2018-12-13 15:58 ` [PATCH v2 2/8] parse_hide_refs_config: handle NULL section Ævar Arnfjörð Bjarmason
2018-12-13 15:58 ` [PATCH v2 3/8] upload-pack: support hidden refs with protocol v2 Ævar Arnfjörð Bjarmason
2018-12-13 15:58 ` [PATCH v2 4/8] tests: add a check for unportable env --unset Ævar Arnfjörð Bjarmason
2018-12-13 15:58 ` [PATCH v2 5/8] tests: add a special setup where for protocol.version Ævar Arnfjörð Bjarmason
2018-12-13 19:48 ` Jonathan Tan
2018-12-13 15:58 ` [PATCH v2 6/8] tests: mark & fix tests broken under GIT_TEST_PROTOCOL_VERSION=1 Ævar Arnfjörð Bjarmason
2018-12-13 15:58 ` [PATCH v2 7/8] builtin/fetch-pack: support protocol version 2 Ævar Arnfjörð Bjarmason
2018-12-14 10:17 ` Jeff King
2018-12-13 15:58 ` [PATCH v2 8/8] tests: mark tests broken under GIT_TEST_PROTOCOL_VERSION=2 Ævar Arnfjörð Bjarmason
2018-12-13 16:08 ` Ævar Arnfjörð Bjarmason
2018-12-14 2:18 ` Junio C Hamano
2018-12-14 10:12 ` Jeff King
2018-12-14 10:55 ` Ævar Arnfjörð Bjarmason
2018-12-14 11:08 ` Ævar Arnfjörð Bjarmason
2018-12-17 19:59 ` Jeff King
2018-12-17 19:57 ` Jeff King
2018-12-17 22:16 ` [PATCH] upload-pack: turn on uploadpack.allowAnySHA1InWant=true Ævar Arnfjörð Bjarmason
2018-12-17 22:34 ` David Turner
2018-12-17 22:57 ` Ævar Arnfjörð Bjarmason
2018-12-17 23:07 ` David Turner
2018-12-17 23:14 ` [PATCH v2 8/8] tests: mark tests broken under GIT_TEST_PROTOCOL_VERSION=2 Jonathan Nieder
2018-12-17 23:36 ` Ævar Arnfjörð Bjarmason
2018-12-18 0:02 ` Jonathan Nieder
2018-12-18 9:28 ` Ævar Arnfjörð Bjarmason
2018-12-18 12:41 ` Jeff King
2018-12-18 12:36 ` Jeff King
2018-12-18 13:10 ` Ævar Arnfjörð Bjarmason
2018-12-26 22:14 ` Junio C Hamano
2018-12-27 11:26 ` Ævar Arnfjörð Bjarmason
2018-12-27 17:10 ` Jonathan Nieder
2018-12-11 21:21 ` [PATCH 2/3] tests: mark tests broken under GIT_TEST_PROTOCOL_VERSION=1 Ævar Arnfjörð Bjarmason
2018-12-11 21:21 ` [PATCH 3/3] tests: mark tests broken under GIT_TEST_PROTOCOL_VERSION=2 Ævar Arnfjörð Bjarmason
2018-12-13 19:53 ` [PATCH 0/3] protocol v2 and hidden refs Jonathan Tan
2018-12-14 8:35 ` Jeff King
2018-12-15 19:53 ` Ævar Arnfjörð Bjarmason
2018-12-16 10:40 ` Jeff King
2018-12-16 11:47 ` Ævar Arnfjörð Bjarmason
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