CVE-2016-7167.patch

From bf0bb3849422c043f21f56fae57c1cf85e41a272 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Thu, 8 Sep 2016 22:59:54 +0200
Subject: [PATCH] CVE-2016-7167: deny negative string length inputs

Bug: https://curl.haxx.se/docs/adv_20160914.html
---
 lib/escape.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/lib/escape.c b/lib/escape.c
index 04230b4..e61260d 100644
--- a/lib/escape.c
+++ b/lib/escape.c
@@ -76,19 +76,25 @@ char *curl_unescape(const char *string, int length)
 }
 
 char *curl_easy_escape(struct Curl_easy *data, const char *string,
                        int inlength)
 {
-  size_t alloc = (inlength?(size_t)inlength:strlen(string))+1;
+  size_t alloc;
   char *ns;
   char *testing_ptr = NULL;
   unsigned char in; /* we need to treat the characters unsigned */
-  size_t newlen = alloc;
+  size_t newlen;
   size_t strindex=0;
   size_t length;
   CURLcode result;
 
+  if(inlength < 0)
+    return NULL;
+
+  alloc = (inlength?(size_t)inlength:strlen(string))+1;
+  newlen = alloc;
+
   ns = malloc(alloc);
   if(!ns)
     return NULL;
 
   length = alloc-1;
@@ -209,18 +215,20 @@ CURLcode Curl_urldecode(struct Curl_easy *data,
  */
 char *curl_easy_unescape(struct Curl_easy *data, const char *string,
                          int length, int *olen)
 {
   char *str = NULL;
-  size_t inputlen = length;
-  size_t outputlen;
-  CURLcode res = Curl_urldecode(data, string, inputlen, &str, &outputlen,
-                                FALSE);
-  if(res)
-    return NULL;
-  if(olen)
-    *olen = curlx_uztosi(outputlen);
+  if(length >= 0) {
+    size_t inputlen = length;
+    size_t outputlen;
+    CURLcode res = Curl_urldecode(data, string, inputlen, &str, &outputlen,
+                                  FALSE);
+    if(res)
+      return NULL;
+    if(olen)
+      *olen = curlx_uztosi(outputlen);
+  }
   return str;
 }
 
 /* For operating systems/environments that use different malloc/free
    systems for the app and for this library, we provide a free that uses
-- 
2.9.3