From: Matthew DeVore <matvore@google.com>
Date: Tue, 4 Jun 2019 17:57:05 +0000 (-0700)
Subject: url: do not allow %00 to represent NUL in URLs
X-Git-Tag: v2.23.0-rc0~98^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d37dc239a427a367427f9c4fdf12a148ad811968;p=thirdparty%2Fgit.git

url: do not allow %00 to represent NUL in URLs

There is no reason to allow %00 to terminate a string, so do not allow it.
Otherwise, we end up returning arbitrary content in the string (that which is
after the %00) which is effectively hidden from callers and can escape sanity
checks and validation, and possible be used in tandem with a security
vulnerability to introduce a payload.

Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Matthew DeVore <matvore@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/url.c b/url.c
index 9ea9d5611b..1b8ef78cea 100644
--- a/url.c
+++ b/url.c
@@ -48,7 +48,7 @@ static char *url_decode_internal(const char **query, int len,
 
 		if (c == '%' && (len < 0 || len >= 3)) {
 			int val = hex2chr(q + 1);
-			if (0 <= val) {
+			if (0 < val) {
 				strbuf_addch(out, val);
 				q += 3;
 				len -= 3;