tool_operate: refuse (--data or --form) and --continue-at combo

libcurl assumes that a --continue-at resumption is done to continue an
upload using the read callback and neither --data nor --form use
that and thus won't do what the user wants. Whatever the user wants
with this strange combination.

Add test 426 to verify.

Reported-by: Smackd0wn on github
Fixes #11081
Closes #11083

1 files changed, 19 insertions, 8 deletions

diff --git a/src/tool_operate.c b/src/tool_operate.c
index 06ae39396..4da9dea16 100644
--- a/src/tool_operate.c
+++ b/src/tool_operate.c
@@ -1398,19 +1398,30 @@ static CURLcode single_transfer(struct GlobalConfig *global,
 
         switch(config->httpreq) {
         case HTTPREQ_SIMPLEPOST:
-          my_setopt_str(curl, CURLOPT_POSTFIELDS,
-                        config->postfields);
-          my_setopt(curl, CURLOPT_POSTFIELDSIZE_LARGE,
-                    config->postfieldsize);
+          if(config->resume_from) {
+            errorf(global, "cannot mix --continue-at with --data\n");
+            result = CURLE_FAILED_INIT;
+          }
+          else {
+            my_setopt_str(curl, CURLOPT_POSTFIELDS,
+                          config->postfields);
+            my_setopt(curl, CURLOPT_POSTFIELDSIZE_LARGE,
+                      config->postfieldsize);
+          }
           break;
         case HTTPREQ_MIMEPOST:
           /* free previous remainders */
           curl_mime_free(config->mimepost);
           config->mimepost = NULL;
-          result = tool2curlmime(curl, config->mimeroot, &config->mimepost);
-          if(result)
-            break;
-          my_setopt_mimepost(curl, CURLOPT_MIMEPOST, config->mimepost);
+          if(config->resume_from) {
+            errorf(global, "cannot mix --continue-at with --form\n");
+            result = CURLE_FAILED_INIT;
+          }
+          else {
+            result = tool2curlmime(curl, config->mimeroot, &config->mimepost);
+            if(!result)
+              my_setopt_mimepost(curl, CURLOPT_MIMEPOST, config->mimepost);
+          }
           break;
         default:
           break;