dispose http(s) 416 error page as non-content

Real webservers (like apache) actually send an error page with a 416
response, but our client didn't expect it leaving the page on the socket
to be parsed as response for the next request (http) or as file content
(https), which isn't what we want at all… Symptom is a "Bad header line"
as html usually doesn't parse that well to an http-header.

This manifests itself e.g. if we have a complete file (or larger) in
partial/ which isn't discarded by If-Range as the server doesn't support
it (or it is just newer, think: mirror rotation).
It is a sort-of regression of 78c72d0ce22e00b194251445aae306df357d5c1a,
which removed the filesize - 1 trick, but this had its own problems…

To properly test this our webserver gains the ability to reply with
transfer-encoding: chunked as most real webservers will use it to send
the dynamically generated error pages.

(The tests and their binary helpers had to be slightly modified to
apply, but the patch to fix the issue itself is unchanged.)

Closes: 768797

1 files changed, 10 insertions, 2 deletions

diff --git a/methods/https.cc b/methods/https.cc
index 0499af0c5..65a744e2a 100644
--- a/methods/https.cc
+++ b/methods/https.cc
@@ -59,6 +59,9 @@ HttpsMethod::parse_header(void *buffer, size_t size, size_t nmemb, void *userp)
       {
          me->Server->Result = 200;
 	 me->Server->StartPos = me->Server->Size;
+	 // the actual size is not important for https as curl will deal with it
+	 // by itself and e.g. doesn't bother us with transport-encoding…
+	 me->Server->JunkSize = std::numeric_limits<unsigned long long>::max();
       }
       else
 	 me->Server->StartPos = 0;
@@ -76,13 +79,18 @@ size_t
 HttpsMethod::write_data(void *buffer, size_t size, size_t nmemb, void *userp)
 {
    HttpsMethod *me = (HttpsMethod *)userp;
+   size_t buffer_size = size * nmemb;
+   // we don't need to count the junk here, just drop anything we get as
+   // we don't always know how long it would be, e.g. in chunked encoding.
+   if (me->Server->JunkSize != 0)
+      return buffer_size;
 
    if (me->Res.Size == 0)
       me->URIStart(me->Res);
-   if(me->File->Write(buffer, size*nmemb) != true)
+   if(me->File->Write(buffer, buffer_size) != true)
       return false;
 
-   return size*nmemb;
+   return buffer_size;
 }
 
 int