http, imap-send: stop using CURLOPT_VERBOSE

Whenever GIT_CURL_VERBOSE is set, teach Git to behave as if
GIT_TRACE_CURL=1 and GIT_TRACE_CURL_NO_DATA=1 is set, instead of setting
CURLOPT_VERBOSE.

This is to prevent inadvertent revelation of sensitive data. In
particular, GIT_CURL_VERBOSE redacts neither the "Authorization" header
nor any cookies specified by GIT_REDACT_COOKIES.

Unifying the tracing mechanism also has the future benefit that any
improvements to the tracing mechanism will benefit both users of
GIT_CURL_VERBOSE and GIT_TRACE_CURL, and we do not need to remember to
implement any improvement twice.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: jonathantanmy

Documentation/git.txt

@@ -721,8 +721,6 @@ of clones and fetches.
 	Enables a curl full trace dump of all incoming and outgoing data,
 	including descriptive information, of the git transport protocol.
 	This is similar to doing curl `--trace-ascii` on the command line.
-	This option overrides setting the `GIT_CURL_VERBOSE` environment
-	variable.
 	See `GIT_TRACE` for available trace output options.
 
 `GIT_TRACE_CURL_NO_DATA`::

http.c

@@ -804,6 +804,12 @@ static int curl_trace(CURL *handle, curl_infotype type, char *data, size_t size,
 	return 0;
 }
 
+void http_trace_curl_no_data(void)
+{
+	trace_override_envvar(&trace_curl, "1");
+	trace_curl_data = 0;
+}
+
 void setup_curl_trace(CURL *handle)
 {
 	if (!trace_want(&trace_curl))
@@ -993,7 +999,7 @@ static CURL *get_curl_handle(void)
 	warning(_("Protocol restrictions not supported with cURL < 7.19.4"));
 #endif
 	if (getenv("GIT_CURL_VERBOSE"))
-		curl_easy_setopt(result, CURLOPT_VERBOSE, 1L);
+		http_trace_curl_no_data();
 	setup_curl_trace(result);
 	if (getenv("GIT_TRACE_CURL_NO_DATA"))
 		trace_curl_data = 0;

http.h

@@ -252,6 +252,13 @@ int finish_http_object_request(struct http_object_request *freq);
 void abort_http_object_request(struct http_object_request *freq);
 void release_http_object_request(struct http_object_request *freq);
 
+/*
+ * Instead of using environment variables to determine if curl tracing happens,
+ * behave as if GIT_TRACE_CURL=1 and GIT_TRACE_CURL_NO_DATA=1 is set. Call this
+ * before calling setup_curl_trace().
+ */
+void http_trace_curl_no_data(void);
+
 /* setup routine for curl_easy_setopt CURLOPT_DEBUGFUNCTION */
 void setup_curl_trace(CURL *handle);
 #endif /* HTTP_H */

imap-send.c

@@ -1464,7 +1464,7 @@ static CURL *setup_curl(struct imap_server_conf *srvc, struct credential *cred)
 	curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
 
 	if (0 < verbosity || getenv("GIT_CURL_VERBOSE"))
-		curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
+		http_trace_curl_no_data();
 	setup_curl_trace(curl);
 
 	return curl;

t/t5551-http-fetch-smart.sh

@@ -197,6 +197,18 @@ test_expect_success 'GIT_TRACE_CURL redacts auth details' '
 	grep "Authorization: Basic <redacted>" trace
 '
 
+test_expect_success 'GIT_CURL_VERBOSE redacts auth details' '
+	rm -rf redact-auth trace &&
+	set_askpass user@host pass@host &&
+	GIT_CURL_VERBOSE=1 git clone --bare "$HTTPD_URL/auth/smart/repo.git" redact-auth 2>trace &&
+	expect_askpass both user@host &&
+
+	# Ensure that there is no "Basic" followed by a base64 string, but that
+	# the auth details are redacted
+	! grep "Authorization: Basic [0-9a-zA-Z+/]" trace &&
+	grep "Authorization: Basic <redacted>" trace
+'
+
 test_expect_success 'disable dumb http on server' '
 	git --git-dir="$HTTPD_DOCUMENT_ROOT_PATH/repo.git" \
 		config http.getanyfile false
@@ -454,6 +466,18 @@ test_expect_success 'GIT_REDACT_COOKIES redacts cookies' '
 	! grep "Cookie:.*Bar=2" err
 '
 
+test_expect_success 'GIT_REDACT_COOKIES redacts cookies when GIT_CURL_VERBOSE=1' '
+	rm -rf clone &&
+	echo "Set-Cookie: Foo=1" >cookies &&
+	echo "Set-Cookie: Bar=2" >>cookies &&
+	GIT_CURL_VERBOSE=1 GIT_REDACT_COOKIES=Bar,Baz \
+		git -c "http.cookieFile=$(pwd)/cookies" clone \
+		$HTTPD_URL/smart/repo.git clone 2>err &&
+	grep "Cookie:.*Foo=1" err &&
+	grep "Cookie:.*Bar=<redacted>" err &&
+	! grep "Cookie:.*Bar=2" err
+'
+
 test_expect_success 'GIT_REDACT_COOKIES handles empty values' '
 	rm -rf clone &&
 	echo "Set-Cookie: Foo=" >cookies &&

t/t5581-http-curl-verbose.sh

@@ -20,7 +20,7 @@ test_expect_success 'failure in git-upload-pack is shown' '
 	test_might_fail env GIT_CURL_VERBOSE=1 \
 		git clone "$HTTPD_URL/error_git_upload_pack/smart/repo.git" \
 		2>curl_log &&
-	grep "< HTTP/1.1 500 Intentional Breakage" curl_log
+	grep "<= Recv header: HTTP/1.1 500 Intentional Breakage" curl_log
 '
 
 test_done

trace.c

@@ -29,15 +29,15 @@ struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
 struct trace_key trace_setup_key = TRACE_KEY_INIT(SETUP);
 
 /* Get a trace file descriptor from "key" env variable. */
-static int get_trace_fd(struct trace_key *key)
+static int get_trace_fd(struct trace_key *key, const char *override_envvar)
 {
 	const char *trace;
 
 	/* don't open twice */
 	if (key->initialized)
 		return key->fd;
 
-	trace = getenv(key->key);
+	trace = override_envvar ? override_envvar : getenv(key->key);
 
 	if (!trace || !strcmp(trace, "") ||
 	    !strcmp(trace, "0") || !strcasecmp(trace, "false"))
@@ -68,6 +68,18 @@ static int get_trace_fd(struct trace_key *key)
 	return key->fd;
 }
 
+void trace_override_envvar(struct trace_key *key, const char *value)
+{
+	trace_disable(key);
+	key->initialized = 0;
+
+	/*
+	 * Invoke get_trace_fd() to initialize key using the given value
+	 * instead of the value of the environment variable.
+	 */
+	get_trace_fd(key, value);
+}
+
 void trace_disable(struct trace_key *key)
 {
 	if (key->need_close)
@@ -112,7 +124,7 @@ static int prepare_trace_line(const char *file, int line,
 
 static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 {
-	if (write_in_full(get_trace_fd(key), buf, len) < 0) {
+	if (write_in_full(get_trace_fd(key, NULL), buf, len) < 0) {
 		warning("unable to write trace for %s: %s",
 			key->key, strerror(errno));
 		trace_disable(key);
@@ -383,7 +395,7 @@ void trace_repo_setup(const char *prefix)
 
 int trace_want(struct trace_key *key)
 {
-	return !!get_trace_fd(key);
+	return !!get_trace_fd(key, NULL);
 }
 
 #if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)

trace.h

@@ -101,6 +101,12 @@ void trace_repo_setup(const char *prefix);
  */
 int trace_want(struct trace_key *key);
 
+/**
+ * Enables or disables tracing for the specified key, as if the environment
+ * variable was set to the given value.
+ */
+void trace_override_envvar(struct trace_key *key, const char *value);
+
 /**
  * Disables tracing for the specified key, even if the environment variable
  * was set.