fetch-pack: redact packfile urls in traces

In some setups, packfile uris act as bearer token. It is not
recommended to expose them plainly in logs, although in special
circunstances (e.g. debug) it makes sense to write them.

Redact the packfile URL paths by default, unless the GIT_TRACE_REDACT
variable is set to false. This mimics the redacting of the Authorization
header in HTTP.

Signed-off-by: Ivan Frade <ifrade@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 39 insertions, 1 deletions

diff --git a/pkt-line.c b/pkt-line.c
index 2dc8ac274b..8e43c2def4 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -370,6 +370,32 @@ int packet_length(const char lenbuf_hex[4])
 	return (val < 0) ? val : (val << 8) | hex2chr(lenbuf_hex + 2);
 }
 
+static char *find_packfile_uri_path(const char *buffer)
+{
+	const char *URI_MARK = "://";
+	char *path;
+	int len;
+
+	/* First char is sideband mark */
+	buffer += 1;
+
+	len = strspn(buffer, "0123456789abcdefABCDEF");
+	/* size of SHA1 and SHA256 hash */
+	if (!(len == 40 || len == 64) || buffer[len] != ' ')
+		return NULL; /* required "<hash>SP" not seen */
+
+	path = strstr(buffer + len + 1, URI_MARK);
+	if (!path)
+		return NULL;
+
+	path = strchr(path + strlen(URI_MARK), '/');
+	if (!path || !*(path + 1))
+		return NULL;
+
+	/* position after '/' */
+	return ++path;
+}
+
 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 						size_t *src_len, char *buffer,
 						unsigned size, int *pktlen,
@@ -377,6 +403,7 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 {
 	int len;
 	char linelen[4];
+	char *uri_path_start;
 
 	if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
 		*pktlen = -1;
@@ -427,7 +454,18 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
 		len--;
 
 	buffer[len] = 0;
-	packet_trace(buffer, len, 0);
+	if (options & PACKET_READ_REDACT_URI_PATH &&
+	    (uri_path_start = find_packfile_uri_path(buffer))) {
+		const char *redacted = "<redacted>";
+		struct strbuf tracebuf = STRBUF_INIT;
+		strbuf_insert(&tracebuf, 0, buffer, len);
+		strbuf_splice(&tracebuf, uri_path_start - buffer,
+			      strlen(uri_path_start), redacted, strlen(redacted));
+		packet_trace(tracebuf.buf, tracebuf.len, 0);
+		strbuf_release(&tracebuf);
+	} else {
+		packet_trace(buffer, len, 0);
+	}
 
 	if ((options & PACKET_READ_DIE_ON_ERR_PACKET) &&
 	    starts_with(buffer, "ERR "))