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authorBrandon Williams <bmwill@google.com>2016-12-14 22:39:52 (GMT)
committerJunio C Hamano <gitster@pobox.com>2016-12-15 17:29:13 (GMT)
commitf1762d772e9b415a3163abf5f217fc3b71a3b40e (patch)
tree763946ed8ce07f24b1ad95a1ba71b497eee796d2 /transport.c
parentf962ddf6edb199b2611d575a75f60d20d5c137c3 (diff)
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transport: add protocol policy config option
Previously the `GIT_ALLOW_PROTOCOL` environment variable was used to specify a whitelist of protocols to be used in clone/fetch/push commands. This patch introduces new configuration options for more fine-grained control for allowing/disallowing protocols. This also has the added benefit of allowing easier construction of a protocol whitelist on systems where setting an environment variable is non-trivial. Now users can specify a policy to be used for each type of protocol via the 'protocol.<name>.allow' config option. A default policy for all unconfigured protocols can be set with the 'protocol.allow' config option. If no user configured default is made git will allow known-safe protocols (http, https, git, ssh, file), disallow known-dangerous protocols (ext), and have a default policy of `user` for all other protocols. The supported policies are `always`, `never`, and `user`. The `user` policy can be used to configure a protocol to be usable when explicitly used by a user, while disallowing it for commands which run clone/fetch/push commands without direct user intervention (e.g. recursive initialization of submodules). Commands which can potentially clone/fetch/push from untrusted repositories without user intervention can export `GIT_PROTOCOL_FROM_USER` with a value of '0' to prevent protocols configured to the `user` policy from being used. Fix remote-ext tests to use the new config to allow the ext protocol to be tested. Based on a patch by Jeff King <peff@peff.net> Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'transport.c')
-rw-r--r--transport.c75
1 files changed, 73 insertions, 2 deletions
diff --git a/transport.c b/transport.c
index dff929e..fbd799d 100644
--- a/transport.c
+++ b/transport.c
@@ -617,10 +617,81 @@ 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;
+
+ 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;
+
+ /* first check the per-protocol config */
+ 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);
+
+ /* if defined, fallback to user-defined default for unknown protocols */
+ if (!git_config_get_string("protocol.allow", &value)) {
+ enum protocol_allow_config ret =
+ parse_protocol_config("protocol.allow", value);
+ free(value);
+ return ret;
+ }
+
+ /* fallback to built-in defaults */
+ /* 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; by default 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);
+ }
+
+ die("BUG: invalid protocol_allow_config type");
}
void transport_check_allowed(const char *type)