[PATCH v9 5/5] transport: add from_user parameter to is_transport_allowed

[Brandon Williams <bmwill@google.com>]

Add the from_user parameter to the 'is_transport_allowed' function.
This allows callers to query if a transport protocol is allowed, given
that the caller knows that the protocol is coming from the user (1) or
not from the user (0) such as redirects in libcurl.  If unknown a -1
should be provided which falls back to reading `GIT_PROTOCOL_FROM_USER`
to determine if the protocol came from the user.

Signed-off-by: Brandon Williams <bmwill@google.com>
---
 http.c      | 14 +++++++-------
 transport.c |  8 +++++---
 transport.h | 13 ++++++++++---
 3 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/http.c b/http.c
index f7c488a..2208269 100644
--- a/http.c
+++ b/http.c
@@ -489,17 +489,17 @@ static void set_curl_keepalive(CURL *c)
 }
 #endif
 
-static long get_curl_allowed_protocols(void)
+static long get_curl_allowed_protocols(int from_user)
 {
 	long allowed_protocols = 0;
 
-	if (is_transport_allowed("http"))
+	if (is_transport_allowed("http", from_user))
 		allowed_protocols |= CURLPROTO_HTTP;
-	if (is_transport_allowed("https"))
+	if (is_transport_allowed("https", from_user))
 		allowed_protocols |= CURLPROTO_HTTPS;
-	if (is_transport_allowed("ftp"))
+	if (is_transport_allowed("ftp", from_user))
 		allowed_protocols |= CURLPROTO_FTP;
-	if (is_transport_allowed("ftps"))
+	if (is_transport_allowed("ftps", from_user))
 		allowed_protocols |= CURLPROTO_FTPS;
 
 	return allowed_protocols;
@@ -588,9 +588,9 @@ static CURL *get_curl_handle(void)
 #endif
 #if LIBCURL_VERSION_NUM >= 0x071304
 	curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS,
-			 get_curl_allowed_protocols());
+			 get_curl_allowed_protocols(0));
 	curl_easy_setopt(result, CURLOPT_PROTOCOLS,
-			 get_curl_allowed_protocols());
+			 get_curl_allowed_protocols(-1));
 #else
 	warning("protocol restrictions not applied to curl redirects because\n"
 		"your curl version is too old (>= 7.19.4)");
diff --git a/transport.c b/transport.c
index fbd799d..f50c31a 100644
--- a/transport.c
+++ b/transport.c
@@ -676,7 +676,7 @@ static enum protocol_allow_config get_protocol_config(const char *type)
 	return PROTOCOL_ALLOW_USER_ONLY;
 }
 
-int is_transport_allowed(const char *type)
+int is_transport_allowed(const char *type, int from_user)
 {
 	const struct string_list *whitelist = protocol_whitelist();
 	if (whitelist)
@@ -688,7 +688,9 @@ int is_transport_allowed(const char *type)
 	case PROTOCOL_ALLOW_NEVER:
 		return 0;
 	case PROTOCOL_ALLOW_USER_ONLY:
-		return git_env_bool("GIT_PROTOCOL_FROM_USER", 1);
+		if (from_user < 0)
+			from_user = git_env_bool("GIT_PROTOCOL_FROM_USER", 1);
+		return from_user;
 	}
 
 	die("BUG: invalid protocol_allow_config type");
@@ -696,7 +698,7 @@ int is_transport_allowed(const char *type)
 
 void transport_check_allowed(const char *type)
 {
-	if (!is_transport_allowed(type))
+	if (!is_transport_allowed(type, -1))
 		die("transport '%s' not allowed", type);
 }
 
diff --git a/transport.h b/transport.h
index 3396e1d..4f1c801 100644
--- a/transport.h
+++ b/transport.h
@@ -142,10 +142,17 @@ struct transport {
 struct transport *transport_get(struct remote *, const char *);
 
 /*
- * Check whether a transport is allowed by the environment. Type should
- * generally be the URL scheme, as described in Documentation/git.txt
+ * Check whether a transport is allowed by the environment.
+ *
+ * Type should generally be the URL scheme, as described in
+ * Documentation/git.txt
+ *
+ * from_user specifies if the transport was given by the user.  If unknown pass
+ * a -1 to read from the environment to determine if the transport was given by
+ * the user.
+ *
  */
-int is_transport_allowed(const char *type);
+int is_transport_allowed(const char *type, int from_user);
 
 /*
  * Check whether a transport is allowed by the environment,
-- 
2.8.0.rc3.226.g39d4020