From: Jeff King <peff@peff.net>
To: Brandon Williams <bmwill@google.com>
Cc: Jonathan Nieder <jrnieder@gmail.com>,
git@vger.kernel.org, Stefan Beller <sbeller@google.com>,
Blake Burkhart <bburky@bburky.com>
Subject: Re: [PATCH] transport: add core.allowProtocol config option
Date: Thu, 3 Nov 2016 14:24:28 -0400 [thread overview]
Message-ID: <20161103182428.j3r574evsk7ypfie@sigill.intra.peff.net> (raw)
In-Reply-To: <20161103175327.nn2yasvlsxsy22be@sigill.intra.peff.net>
On Thu, Nov 03, 2016 at 01:53:27PM -0400, Jeff King wrote:
> I'd design the new system from scratch, and have it kick in _only_ when
> GIT_ALLOW_PROTOCOL is not set. That lets existing callers continue to
> have the safe behavior until they are ready to move to the new format.
>
> Something like the patch below (which is just for illustration, and not
> tested beyond compilation).
Here's that same patch with a few tweaks:
- it changes git-submodule to use the new, more flexible system (which
also gets a it a lot more test coverage)
- it tweaks two tests which use the "ext" helper to enable it (since
it's blacklisted by default; I have mixed feelings on that, but I
see why Blake wants it, as it would have protected things like "go
get" out of the box).
- it adds "file://" as a known-good protocol, even for submodules,
which matches the current code. I am not sure if this is reasonable
or not. A malicious repository probably can't do much by pointing
you to cloning your own repo as a submodule unless you then _also_
run some arbitrary code to expose it, at which point it's generally
game-over anyway.
And I'd expect automated services (like GitHub Pages) to already
have a cut-down whitelist via GIT_ALLOW_PROTOCOL (and I happen to
know that it goes).
So this seems like a reasonable direction to me. It obviously needs
documentation and tests. Arguably there should be a fallback "allow"
value when a protocol is not mentioned in the config so that you could
convert the default from "user" to "never" if you wanted your config to
specify a pure whitelist.
Without that, I think we'd want to keep GIT_ALLOW_PROTOCOL for the truly
paranoid (though we should keep it indefinitely either way for backwards
compatibility).
Do you have interest in picking this up and running with it?
-Peff
diff --git a/git-submodule.sh b/git-submodule.sh
index a024a135d..0a477b4c9 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -21,14 +21,10 @@ require_work_tree
wt_prefix=$(git rev-parse --show-prefix)
cd_to_toplevel
-# Restrict ourselves to a vanilla subset of protocols; the URLs
-# we get are under control of a remote repository, and we do not
-# want them kicking off arbitrary git-remote-* programs.
-#
-# If the user has already specified a set of allowed protocols,
-# we assume they know what they're doing and use that instead.
-: ${GIT_ALLOW_PROTOCOL=file:git:http:https:ssh}
-export GIT_ALLOW_PROTOCOL
+# Tell the rest of git that any URLs we get don't come
+# directly from the user, so it can apply policy as appropriate.
+GIT_PROTOCOL_FROM_USER=0
+export GIT_PROTOCOL_FROM_USER
command=
branch=
diff --git a/t/t5509-fetch-push-namespaces.sh b/t/t5509-fetch-push-namespaces.sh
index bc44ac36d..75c570adc 100755
--- a/t/t5509-fetch-push-namespaces.sh
+++ b/t/t5509-fetch-push-namespaces.sh
@@ -4,6 +4,7 @@ test_description='fetch/push involving ref namespaces'
. ./test-lib.sh
test_expect_success setup '
+ git config --global protocol.ext.allow user &&
test_tick &&
git init original &&
(
diff --git a/t/t5802-connect-helper.sh b/t/t5802-connect-helper.sh
index b7a7f9d58..c6c266187 100755
--- a/t/t5802-connect-helper.sh
+++ b/t/t5802-connect-helper.sh
@@ -4,6 +4,7 @@ test_description='ext::cmd remote "connect" helper'
. ./test-lib.sh
test_expect_success setup '
+ git config --global protocol.ext.allow user &&
test_tick &&
git commit --allow-empty -m initial &&
test_tick &&
diff --git a/transport.c b/transport.c
index d57e8dec2..cd603fbf5 100644
--- a/transport.c
+++ b/transport.c
@@ -664,10 +664,70 @@ static const struct string_list *protocol_whitelist(void)
return enabled ? &allowed : NULL;
}
+enum protocol_allow_config {
+ PROTOCOL_ALLOW_NEVER = 0,
+ PROTOCOL_ALLOW_USER_ONLY,
+ PROTOCOL_ALLOW_ALWAYS
+};
+
+static enum protocol_allow_config parse_protocol_config(const char *key,
+ const char *value)
+{
+ if (!strcasecmp(value, "always"))
+ return PROTOCOL_ALLOW_ALWAYS;
+ else if (!strcasecmp(value, "never"))
+ return PROTOCOL_ALLOW_NEVER;
+ else if (!strcasecmp(value, "user"))
+ return PROTOCOL_ALLOW_USER_ONLY;
+
+ /* XXX maybe also interpret git_config_bool() here? */
+ die("unknown value for config '%s': %s", key, value);
+}
+
+static enum protocol_allow_config get_protocol_config(const char *type)
+{
+ char *key = xstrfmt("protocol.%s.allow", type);
+ char *value;
+
+ if (!git_config_get_string(key, &value)) {
+ enum protocol_allow_config ret =
+ parse_protocol_config(key, value);
+ free(key);
+ free(value);
+ return ret;
+ }
+ free(key);
+
+ /* known safe */
+ if (!strcmp(type, "http") ||
+ !strcmp(type, "https") ||
+ !strcmp(type, "git") ||
+ !strcmp(type, "ssh") ||
+ !strcmp(type, "file"))
+ return PROTOCOL_ALLOW_ALWAYS;
+
+ /* known scary; err on the side of caution */
+ if (!strcmp(type, "ext"))
+ return PROTOCOL_ALLOW_NEVER;
+
+ /* unknown; let them be used only directly by the user */
+ return PROTOCOL_ALLOW_USER_ONLY;
+}
+
int is_transport_allowed(const char *type)
{
- const struct string_list *allowed = protocol_whitelist();
- return !allowed || string_list_has_string(allowed, type);
+ const struct string_list *whitelist = protocol_whitelist();
+ if (whitelist)
+ return string_list_has_string(whitelist, type);
+
+ switch (get_protocol_config(type)) {
+ case PROTOCOL_ALLOW_ALWAYS:
+ return 1;
+ case PROTOCOL_ALLOW_NEVER:
+ return 0;
+ case PROTOCOL_ALLOW_USER_ONLY:
+ return git_env_bool("GIT_PROTOCOL_FROM_USER", 1);
+ }
}
void transport_check_allowed(const char *type)
next prev parent reply other threads:[~2016-11-03 18:24 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 22:20 [PATCH] transport: add core.allowProtocol config option Brandon Williams
2016-11-02 22:41 ` Stefan Beller
2016-11-02 22:47 ` Brandon Williams
2016-11-02 23:05 ` Jeff King
2016-11-02 23:08 ` Jeff King
2016-11-02 23:34 ` Brandon Williams
2016-11-02 23:33 ` Brandon Williams
2016-11-02 23:46 ` Brandon Williams
2016-11-03 0:08 ` Jeff King
2016-11-03 0:22 ` Jonathan Nieder
2016-11-03 0:41 ` Blake Burkhart
2016-11-03 2:44 ` Junio C Hamano
2016-11-03 14:38 ` Jeff King
2016-11-03 17:25 ` Brandon Williams
2016-11-03 17:39 ` Stefan Beller
2016-11-03 17:51 ` Brandon Williams
2016-11-03 18:02 ` Jeff King
2016-11-03 18:08 ` Brandon Williams
2016-11-03 18:00 ` Jeff King
2016-11-03 17:53 ` Jeff King
2016-11-03 18:19 ` Brandon Williams
2016-11-03 18:25 ` Jeff King
2016-11-03 18:24 ` Jeff King [this message]
2016-11-03 18:45 ` Brandon Williams
2016-11-03 18:50 ` Jeff King
2016-11-03 18:56 ` Brandon Williams
2016-11-03 0:50 ` [PATCH v2] " Brandon Williams
2016-11-04 20:55 ` [PATCH v3] transport: add protocol policy " Brandon Williams
2016-11-04 20:58 ` Brandon Williams
2016-11-04 21:35 ` Stefan Beller
2016-11-04 23:09 ` Jeff King
2016-11-05 0:18 ` Brandon Williams
2016-11-04 22:38 ` Stefan Beller
2016-11-07 18:14 ` Brandon Williams
2016-11-04 23:06 ` Jeff King
2016-11-07 19:17 ` Brandon Williams
2016-11-07 19:35 ` [PATCH v4 1/2] lib-proto-disable: variable name fix Brandon Williams
2016-11-07 19:35 ` [PATCH v4 2/2] transport: add protocol policy config option Brandon Williams
2016-11-07 20:44 ` Jeff King
2016-11-07 21:02 ` Brandon Williams
2016-11-07 20:26 ` [PATCH v4 1/2] lib-proto-disable: variable name fix Jeff King
2016-11-07 20:40 ` Brandon Williams
2016-11-07 20:48 ` Jeff King
2016-11-08 3:32 ` Jacob Keller
2016-11-08 20:52 ` Junio C Hamano
2016-11-07 21:51 ` [PATCH v5 " Brandon Williams
2016-11-07 21:51 ` [PATCH v5 2/2] transport: add protocol policy config option Brandon Williams
2016-11-08 22:04 ` Jeff King
2016-11-08 22:05 ` Brandon Williams
2016-12-01 19:44 ` [PATCH v6 0/4] transport protocol policy configuration Brandon Williams
2016-12-01 19:44 ` [PATCH v6 1/4] lib-proto-disable: variable name fix Brandon Williams
2016-12-01 19:44 ` [PATCH v6 2/4] transport: add protocol policy config option Brandon Williams
2016-12-01 19:44 ` [PATCH v6 3/4] http: always warn if libcurl version is too old Brandon Williams
2016-12-01 19:44 ` [PATCH v6 4/4] transport: check if protocol can be used on a redirect Brandon Williams
2016-12-01 19:48 ` Brandon Williams
2016-12-01 19:49 ` Brandon Williams
2016-12-01 19:50 ` Jeff King
2016-12-01 19:54 ` Junio C Hamano
2016-12-01 19:59 ` Jeff King
2016-12-01 20:01 ` Brandon Williams
2016-12-01 20:25 ` [PATCH v7 0/4] transport protocol policy configuration Brandon Williams
2016-12-01 20:25 ` [PATCH v7 1/4] lib-proto-disable: variable name fix Brandon Williams
2016-12-01 20:25 ` [PATCH v7 2/4] transport: add protocol policy config option Brandon Williams
2016-12-01 20:25 ` [PATCH v7 3/4] http: always warn if libcurl version is too old Brandon Williams
2016-12-01 20:25 ` [PATCH v7 4/4] transport: add from_user parameter to is_transport_allowed Brandon Williams
2016-12-01 21:40 ` Jeff King
2016-12-01 22:25 ` Junio C Hamano
2016-12-01 23:07 ` Brandon Williams
2016-12-01 23:26 ` Brandon Williams
2016-12-02 0:13 ` Jeff King
2016-12-02 17:33 ` Brandon Williams
2016-12-01 23:34 ` Junio C Hamano
2016-12-01 23:58 ` Brandon Williams
2016-12-05 20:04 ` Junio C Hamano
2016-12-05 22:22 ` Brandon Williams
2016-12-05 23:19 ` Junio C Hamano
2016-12-05 23:22 ` Brandon Williams
2016-12-06 13:51 ` Jeff King
2016-12-06 17:53 ` Junio C Hamano
2016-12-06 18:10 ` Jeff King
2016-12-06 18:24 ` [PATCH v2] jk/http-walker-limit-redirect rebased to maint-2.9 Jeff King
2016-12-06 18:24 ` [PATCH v2 1/6] http: simplify update_url_from_redirect Jeff King
2016-12-06 18:24 ` [PATCH v2 2/6] http: always update the base URL for redirects Jeff King
2016-12-06 18:24 ` [PATCH v2 3/6] remote-curl: rename shadowed options variable Jeff King
2016-12-06 18:24 ` [PATCH v2 4/6] http: make redirects more obvious Jeff King
2016-12-06 18:24 ` [PATCH v2 5/6] http: treat http-alternates like redirects Jeff King
2016-12-06 18:25 ` [PATCH v2 6/6] http-walker: complain about non-404 loose object errors Jeff King
2016-12-06 22:24 ` [PATCH v7 4/4] transport: add from_user parameter to is_transport_allowed Brandon Williams
2016-12-02 0:00 ` [PATCH v8 0/5] transport protocol policy configuration Brandon Williams
2016-12-02 0:00 ` [PATCH v8 1/5] lib-proto-disable: variable name fix Brandon Williams
2016-12-02 0:00 ` [PATCH v8 2/5] transport: add protocol policy config option Brandon Williams
2016-12-02 0:01 ` [PATCH v8 3/5] http: always warn if libcurl version is too old Brandon Williams
2016-12-02 0:01 ` [PATCH v8 4/5] http: create function to get curl allowed protocols Brandon Williams
2016-12-02 0:01 ` [PATCH v8 5/5] transport: add from_user parameter to is_transport_allowed Brandon Williams
2016-12-14 1:40 ` [PATCH v9 0/5] transport protocol policy configuration Brandon Williams
2016-12-14 1:40 ` [PATCH v9 1/5] lib-proto-disable: variable name fix Brandon Williams
2016-12-14 1:40 ` [PATCH v9 2/5] transport: add protocol policy config option Brandon Williams
2016-12-14 1:40 ` [PATCH v9 3/5] http: always warn if libcurl version is too old Brandon Williams
2016-12-14 16:01 ` Jeff King
2016-12-14 17:56 ` Brandon Williams
2016-12-14 1:40 ` [PATCH v9 4/5] http: create function to get curl allowed protocols Brandon Williams
2016-12-14 16:03 ` Jeff King
2016-12-14 18:00 ` Brandon Williams
2016-12-14 1:40 ` [PATCH v9 5/5] transport: add from_user parameter to is_transport_allowed Brandon Williams
2016-12-14 16:40 ` Jeff King
2016-12-14 20:13 ` Brandon Williams
2016-12-14 20:33 ` Jeff King
2016-12-14 21:12 ` Jeff King
2016-12-14 21:58 ` Brandon Williams
[not found] ` <CAP3OtXiOPbAkr5Mn+5tEmZZAZzJXQ4CvtpHCg=wt+k-bi6K2vA@mail.gmail.com>
[not found] ` <CAP3OtXhH++szRws20MaHt-ftLBMUJuYiTmfL50mOFP4FA4Mn6Q@mail.gmail.com>
2016-12-14 22:52 ` Jeff King
2016-12-14 20:37 ` Brandon Williams
2016-12-14 20:41 ` Jeff King
2016-12-14 20:50 ` Brandon Williams
2016-12-14 22:39 ` [PATCH v10 0/6] transport protocol policy configuration Brandon Williams
2016-12-14 22:39 ` [PATCH v10 1/6] lib-proto-disable: variable name fix Brandon Williams
2016-12-14 22:39 ` [PATCH v10 2/6] http: always warn if libcurl version is too old Brandon Williams
2016-12-15 0:21 ` Jeff King
2016-12-15 17:29 ` Junio C Hamano
2016-12-14 22:39 ` [PATCH v10 3/6] transport: add protocol policy config option Brandon Williams
2016-12-14 22:39 ` [PATCH v10 4/6] http: create function to get curl allowed protocols Brandon Williams
2016-12-14 22:39 ` [PATCH v10 5/6] transport: add from_user parameter to is_transport_allowed Brandon Williams
2016-12-14 22:39 ` [PATCH v10 6/6] http: respect protocol.*.allow=user for http-alternates Brandon Williams
2016-12-14 23:25 ` [PATCH v10 0/6] transport protocol policy configuration Junio C Hamano
2016-12-15 0:22 ` Jeff King
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