formpost: fix memory leaks in AddFormData error branches

Reported-by: Dmitry-Me
Fixes #688

diff --git a/lib/formdata.c b/lib/formdata.c
index 5ccb9d8b71a17b8525f0a25da82f3eeae722cc7a..454be7610f710875d40072c42c117b39db985d5c 100644 (file)
--- a/lib/formdata.c
+++ b/lib/formdata.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -825,28 +825,34 @@ static CURLcode AddFormData(struct FormData **formp,
                             curl_off_t length,
                             curl_off_t *size)
 {
-  struct FormData *newform = malloc(sizeof(struct FormData));
+  struct FormData *newform;
+  char *alloc2 = NULL;
+  CURLcode result = CURLE_OK;
+  if(length < 0 || (size && *size < 0))
+    return CURLE_BAD_FUNCTION_ARGUMENT;
+
+  newform = malloc(sizeof(struct FormData));
   if(!newform)
     return CURLE_OUT_OF_MEMORY;
   newform->next = NULL;
 
-  if(length < 0 || (size && *size < 0))
-    return CURLE_BAD_FUNCTION_ARGUMENT;
-
   if(type <= FORM_CONTENT) {
     /* we make it easier for plain strings: */
     if(!length)
       length = strlen((char *)line);
 #if (SIZEOF_SIZE_T < CURL_SIZEOF_CURL_OFF_T)
-    else if(length >= (curl_off_t)(size_t)-1)
-      return CURLE_BAD_FUNCTION_ARGUMENT;
+    else if(length >= (curl_off_t)(size_t)-1) {
+      result = CURLE_BAD_FUNCTION_ARGUMENT;
+      goto error;
+    }
 #endif
 
     newform->line = malloc((size_t)length+1);
     if(!newform->line) {
-      free(newform);
-      return CURLE_OUT_OF_MEMORY;
+      result = CURLE_OUT_OF_MEMORY;
+      goto error;
     }
+    alloc2 = newform->line;
     memcpy(newform->line, line, (size_t)length);
     newform->length = (size_t)length;
     newform->line[(size_t)length]=0; /* zero terminate for easier debugging */
@@ -877,12 +883,20 @@ static CURLcode AddFormData(struct FormData **formp,
         struct_stat file;
         if(!stat(newform->line, &file) && !S_ISDIR(file.st_mode))
           *size += filesize(newform->line, file);
-        else
-          return CURLE_BAD_FUNCTION_ARGUMENT;
+        else {
+          result = CURLE_BAD_FUNCTION_ARGUMENT;
+          goto error;
+        }
       }
     }
   }
   return CURLE_OK;
+  error:
+  if(newform)
+    free(newform);
+  if(alloc2)
+    free(alloc2);
+  return result;
 }
 
 /*