From: Daniel Stenberg <daniel@haxx.se>
Date: Tue, 3 Sep 2019 20:59:32 +0000 (+0200)
Subject: security:read_data fix bad realloc()
X-Git-Tag: curl-7_66_0~11
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9069838b30fb3b48af0123e39f664cea683254a5;p=thirdparty%2Fcurl.git

security:read_data fix bad realloc()

... that could end up a double-free

CVE-2019-5481
Bug: https://curl.haxx.se/docs/CVE-2019-5481.html
---

diff --git a/lib/security.c b/lib/security.c
index 550ea2da8d..c5e4e135df 100644
--- a/lib/security.c
+++ b/lib/security.c
@@ -191,7 +191,6 @@ static CURLcode read_data(struct connectdata *conn,
                           struct krb5buffer *buf)
 {
   int len;
-  void *tmp = NULL;
   CURLcode result;
 
   result = socket_read(fd, &len, sizeof(len));
@@ -201,12 +200,11 @@ static CURLcode read_data(struct connectdata *conn,
   if(len) {
     /* only realloc if there was a length */
     len = ntohl(len);
-    tmp = Curl_saferealloc(buf->data, len);
+    buf->data = Curl_saferealloc(buf->data, len);
   }
-  if(tmp == NULL)
+  if(!len || !buf->data)
     return CURLE_OUT_OF_MEMORY;
 
-  buf->data = tmp;
   result = socket_read(fd, buf->data, len);
   if(result)
     return result;