curl_easy_reset: release mime-related data.

Move curl_mime_initpart() and curl_mime_cleanpart() calls to lower-level
functions dealing with UserDefined structure contents.
This avoids memory leakages on curl-generated part mime headers.
New test 2073 checks this using the cli tool --next option: it
triggers a valgrind error if bug is present.

Bug: https://curl.haxx.se/mail/lib-2017-12/0060.html
Reported-by: Martin Galvan

3 files changed, 9 insertions, 8 deletions

diff --git a/lib/easy.c b/lib/easy.c
index 72506488a..75f332b07 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -998,7 +998,7 @@ void curl_easy_reset(struct Curl_easy *data)
   /* zero out UserDefined data: */
   Curl_freeset(data);
   memset(&data->set, 0, sizeof(struct UserDefined));
-  (void)Curl_init_userdefined(&data->set);
+  (void)Curl_init_userdefined(data);
 
   /* zero out Progress data: */
   memset(&data->progress, 0, sizeof(struct Progress));
diff --git a/lib/url.c b/lib/url.c
index 8e0326219..a4f3f37f8 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -293,6 +293,8 @@ void Curl_freeset(struct Curl_easy *data)
     data->change.url_alloc = FALSE;
   }
   data->change.url = NULL;
+
+  Curl_mime_cleanpart(&data->set.mimepost);
 }
 
 /*
@@ -382,8 +384,6 @@ CURLcode Curl_close(struct Curl_easy *data)
   Curl_http2_cleanup_dependencies(data);
   Curl_convert_close(data);
 
-  Curl_mime_cleanpart(&data->set.mimepost);
-
   /* No longer a dirty share, if it exists */
   if(data->share) {
     Curl_share_lock(data, CURL_LOCK_DATA_SHARE, CURL_LOCK_ACCESS_SINGLE);
@@ -402,8 +402,9 @@ CURLcode Curl_close(struct Curl_easy *data)
  * Initialize the UserDefined fields within a Curl_easy.
  * This may be safely called on a new or existing Curl_easy.
  */
-CURLcode Curl_init_userdefined(struct UserDefined *set)
+CURLcode Curl_init_userdefined(struct Curl_easy *data)
 {
+  struct UserDefined *set = &data->set;
   CURLcode result = CURLE_OK;
 
   set->out = stdout; /* default output to stdout */
@@ -453,6 +454,8 @@ CURLcode Curl_init_userdefined(struct UserDefined *set)
   /* make libcurl quiet by default: */
   set->hide_progress = TRUE;  /* CURLOPT_NOPROGRESS changes these */
 
+  Curl_mime_initpart(&set->mimepost, data);
+
   /*
    * libcurl 7.10 introduced SSL verification *by default*! This needs to be
    * switched off unless wanted.
@@ -569,15 +572,13 @@ CURLcode Curl_open(struct Curl_easy **curl)
     result = CURLE_OUT_OF_MEMORY;
   }
   else {
-    Curl_mime_initpart(&data->set.mimepost, data);
-
     data->state.headerbuff = malloc(HEADERSIZE);
     if(!data->state.headerbuff) {
       DEBUGF(fprintf(stderr, "Error: malloc of headerbuff failed\n"));
       result = CURLE_OUT_OF_MEMORY;
     }
     else {
-      result = Curl_init_userdefined(&data->set);
+      result = Curl_init_userdefined(data);
 
       data->state.headersize = HEADERSIZE;
       Curl_convert_init(data);
diff --git a/lib/url.h b/lib/url.h
index 5dd04fdff..0fdb8cf28 100644
--- a/lib/url.h
+++ b/lib/url.h
@@ -33,7 +33,7 @@
 
 CURLcode Curl_init_do(struct Curl_easy *data, struct connectdata *conn);
 CURLcode Curl_open(struct Curl_easy **curl);
-CURLcode Curl_init_userdefined(struct UserDefined *set);
+CURLcode Curl_init_userdefined(struct Curl_easy *data);
 CURLcode Curl_setopt(struct Curl_easy *data, CURLoption option,
                      va_list arg);
 CURLcode Curl_dupset(struct Curl_easy * dst, struct Curl_easy * src);