From a6ae0fbe9c50733e0f645f5bd16e1db38c592c3d Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 31 Jan 2018 08:40:11 +0100
Subject: [PATCH] FTP: reject path components with control codes

Refuse to operate when given path components featuring byte values lower
than 32.

Previously, inserting a %00 sequence early in the directory part when
using the 'singlecwd' ftp method could make curl write a zero byte
outside of the allocated buffer.

Test case 340 verifies.

CVE-2018-1000120
Reported-by: Duy Phan Thanh
Bug: https://curl.haxx.se/docs/adv_2018-9cd6.html
---
 lib/ftp.c               |  8 ++++----
 tests/data/Makefile.inc |  3 +++
 tests/data/test340      | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 4 deletions(-)
 create mode 100644 tests/data/test340

--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -3235,7 +3235,7 @@ static CURLcode ftp_done(struct connectd
 
   if(!result)
     /* get the "raw" path */
-    result = Curl_urldecode(data, path_to_use, 0, &path, NULL, FALSE);
+    result = Curl_urldecode(data, path_to_use, 0, &path, NULL, TRUE);
   if(result) {
     /* We can limp along anyway (and should try to since we may already be in
      * the error path) */
@@ -4241,7 +4241,7 @@ CURLcode ftp_parse_url_path(struct conne
       result = Curl_urldecode(conn->data, slash_pos ? cur_pos : "/",
                               slash_pos ? dirlen : 1,
                               &ftpc->dirs[0], NULL,
-                              FALSE);
+                              TRUE);
       if(result) {
         freedirs(ftpc);
         return result;
@@ -4349,7 +4349,7 @@ CURLcode ftp_parse_url_path(struct conne
     size_t dlen;
     char *path;
     CURLcode result =
-      Curl_urldecode(conn->data, data->state.path, 0, &path, &dlen, FALSE);
+      Curl_urldecode(conn->data, data->state.path, 0, &path, &dlen, TRUE);
     if(result) {
       freedirs(ftpc);
       return result;
