transport: refactor protocol whitelist code

The current callers only want to die when their transport is prohibited. But future callers want to query the mechanism without dying. Let's break out a few query functions, and also save the results in a static list so we don't have to re-parse for each query. Based-on-a-patch-by: Blake Burkhart <bburky@bburky.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Sep 22, 2015 at 18:03 UTC 5088d3b38775f8ac12d7f77636775b16059b67ef
2 files changed +43 -10
transport.c
+30 -8
@@ -909,18 +909,40 @@ static int external_specification_len(const char *url)
909 return strchr(url, ':') - url;
910 }
911
912 -void transport_check_allowed(const char *type)
912 +static const struct string_list *protocol_whitelist(void)
913 {
914 - struct string_list allowed = STRING_LIST_INIT_DUP;
915 - const char *v = getenv("GIT_ALLOW_PROTOCOL");
914 + static int enabled = -1;
915 + static struct string_list allowed = STRING_LIST_INIT_DUP;
916 +
917 + if (enabled < 0) {
918 + const char *v = getenv("GIT_ALLOW_PROTOCOL");
919 + if (v) {
920 + string_list_split(&allowed, v, ':', -1);
921 + string_list_sort(&allowed);
922 + enabled = 1;
923 + } else {
924 + enabled = 0;
925 + }
926 + }
927
917 - if (!v)
918 - return;
928 + return enabled ? &allowed : NULL;
929 +}
930 +
931 +int is_transport_allowed(const char *type)
932 +{
933 + const struct string_list *allowed = protocol_whitelist();
934 + return !allowed || string_list_has_string(allowed, type);
935 +}
936
920 - string_list_split(&allowed, v, ':', -1);
921 - if (!unsorted_string_list_has_string(&allowed, type))
937 +void transport_check_allowed(const char *type)
938 +{
939 + if (!is_transport_allowed(type))
940 die("transport '%s' not allowed", type);
923 - string_list_clear(&allowed, 0);
941 +}
942 +
943 +int transport_restrict_protocols(void)
944 +{
945 + return !!protocol_whitelist();
946 }
947
948 struct transport *transport_get(struct remote *remote, const char *url)
transport.h
+13 -2
@@ -132,13 +132,24 @@ struct transport {
132 /* Returns a transport suitable for the url */
133 struct transport *transport_get(struct remote *, const char *);
134
135 +/*
136 + * Check whether a transport is allowed by the environment. Type should
137 + * generally be the URL scheme, as described in Documentation/git.txt
138 + */
139 +int is_transport_allowed(const char *type);
140 +
141 /*
142 * Check whether a transport is allowed by the environment,
137 - * and die otherwise. type should generally be the URL scheme,
138 - * as described in Documentation/git.txt
143 + * and die otherwise.
144 */
145 void transport_check_allowed(const char *type);
146
147 +/*
148 + * Returns true if the user has attempted to turn on protocol
149 + * restrictions at all.
150 + */
151 +int transport_restrict_protocols(void);
152 +
153 /* Transport options which apply to git:// and scp-style URLs */
154
155 /* The program to use on the remote side to send a pack */