Merge branch 'jt/http-redact-cookies'

The http tracing code, often used to debug connection issues,
learned to redact potentially sensitive information from its output
so that it can be more safely sharable.

* jt/http-redact-cookies:
  http: support omitting data from traces
  http: support cookie redaction when tracing

http.c

@@ -13,8 +13,11 @@
 #include "transport.h"
 #include "packfile.h"
 #include "protocol.h"
+#include "string-list.h"
 
 static struct trace_key trace_curl = TRACE_KEY_INIT(CURL);
+static int trace_curl_data = 1;
+static struct string_list cookies_to_redact = STRING_LIST_INIT_DUP;
 #if LIBCURL_VERSION_NUM >= 0x070a08
 long int git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
 #else
@@ -575,6 +578,54 @@ static void redact_sensitive_header(struct strbuf *header)
 		/* Everything else is opaque and possibly sensitive */
 		strbuf_setlen(header,  sensitive_header - header->buf);
 		strbuf_addstr(header, " <redacted>");
+	} else if (cookies_to_redact.nr &&
+		   skip_prefix(header->buf, "Cookie:", &sensitive_header)) {
+		struct strbuf redacted_header = STRBUF_INIT;
+		char *cookie;
+
+		while (isspace(*sensitive_header))
+			sensitive_header++;
+
+		/*
+		 * The contents of header starting from sensitive_header will
+		 * subsequently be overridden, so it is fine to mutate this
+		 * string (hence the assignment to "char *").
+		 */
+		cookie = (char *) sensitive_header;
+
+		while (cookie) {
+			char *equals;
+			char *semicolon = strstr(cookie, "; ");
+			if (semicolon)
+				*semicolon = 0;
+			equals = strchrnul(cookie, '=');
+			if (!equals) {
+				/* invalid cookie, just append and continue */
+				strbuf_addstr(&redacted_header, cookie);
+				continue;
+			}
+			*equals = 0; /* temporarily set to NUL for lookup */
+			if (string_list_lookup(&cookies_to_redact, cookie)) {
+				strbuf_addstr(&redacted_header, cookie);
+				strbuf_addstr(&redacted_header, "=<redacted>");
+			} else {
+				*equals = '=';
+				strbuf_addstr(&redacted_header, cookie);
+			}
+			if (semicolon) {
+				/*
+				 * There are more cookies. (Or, for some
+				 * reason, the input string ends in "; ".)
+				 */
+				strbuf_addstr(&redacted_header, "; ");
+				cookie = semicolon + strlen("; ");
+			} else {
+				cookie = NULL;
+			}
+		}
+
+		strbuf_setlen(header, sensitive_header - header->buf);
+		strbuf_addbuf(header, &redacted_header);
 	}
 }
 
@@ -645,24 +696,32 @@ static int curl_trace(CURL *handle, curl_infotype type, char *data, size_t size,
 		curl_dump_header(text, (unsigned char *)data, size, DO_FILTER);
 		break;
 	case CURLINFO_DATA_OUT:
-		text = "=> Send data";
-		curl_dump_data(text, (unsigned char *)data, size);
+		if (trace_curl_data) {
+			text = "=> Send data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
 		break;
 	case CURLINFO_SSL_DATA_OUT:
-		text = "=> Send SSL data";
-		curl_dump_data(text, (unsigned char *)data, size);
+		if (trace_curl_data) {
+			text = "=> Send SSL data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
 		break;
 	case CURLINFO_HEADER_IN:
 		text = "<= Recv header";
 		curl_dump_header(text, (unsigned char *)data, size, NO_FILTER);
 		break;
 	case CURLINFO_DATA_IN:
-		text = "<= Recv data";
-		curl_dump_data(text, (unsigned char *)data, size);
+		if (trace_curl_data) {
+			text = "<= Recv data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
 		break;
 	case CURLINFO_SSL_DATA_IN:
-		text = "<= Recv SSL data";
-		curl_dump_data(text, (unsigned char *)data, size);
+		if (trace_curl_data) {
+			text = "<= Recv SSL data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
 		break;
 
 	default:		/* we ignore unknown types by default */
@@ -807,6 +866,13 @@ static CURL *get_curl_handle(void)
 	if (getenv("GIT_CURL_VERBOSE"))
 		curl_easy_setopt(result, CURLOPT_VERBOSE, 1L);
 	setup_curl_trace(result);
+	if (getenv("GIT_TRACE_CURL_NO_DATA"))
+		trace_curl_data = 0;
+	if (getenv("GIT_REDACT_COOKIES")) {
+		string_list_split(&cookies_to_redact,
+				  getenv("GIT_REDACT_COOKIES"), ',', -1);
+		string_list_sort(&cookies_to_redact);
+	}
 
 	curl_easy_setopt(result, CURLOPT_USERAGENT,
 		user_agent ? user_agent : git_user_agent());