progress: count amount of data "delivered" to application

... and apply the CURLOPT_MAXFILESIZE limit (if set) on that as well.
This effectively protects the user against "zip bombs".

Test case 1618 verifies using a 14 byte brotli payload that otherwise
explodes to 102400 zero bytes.

lib/cw-out.c

@@ -31,7 +31,7 @@
 #include "transfer.h"
 #include "cw-out.h"
 #include "cw-pause.h"
-
+#include "progress.h"
 
 /**
  * OVERALL DESIGN of this client writer
@@ -229,7 +229,7 @@ static CURLcode cw_out_ptr_flush(struct cw_out_ctx *ctx,
   void *wcb_data;
   size_t max_write, min_write;
   size_t wlen, nwritten;
-  CURLcode result;
+  CURLcode result = CURLE_OK;
 
   /* If we errored once, we do not invoke the client callback again */
   if(ctx->errored)
@@ -253,8 +253,11 @@ static CURLcode cw_out_ptr_flush(struct cw_out_ctx *ctx,
       if(!flush_all && blen < min_write)
         break;
       wlen = max_write ? CURLMIN(blen, max_write) : blen;
-      result = cw_out_cb_write(ctx, data, wcb, wcb_data, otype,
-                               buf, wlen, &nwritten);
+      if(otype == CW_OUT_BODY)
+        result = Curl_pgrs_deliver_inc(data, wlen);
+      if(!result)
+        result = cw_out_cb_write(ctx, data, wcb, wcb_data, otype,
+                                 buf, wlen, &nwritten);
       if(result)
         return result;
       *pconsumed += nwritten;

lib/progress.c

@@ -211,6 +211,7 @@ void Curl_pgrsReset(struct Curl_easy *data)
   Curl_pgrsSetUploadSize(data, -1);
   Curl_pgrsSetDownloadSize(data, -1);
   data->progress.speeder_c = 0; /* reset speed records */
+  data->progress.deliver = 0;
   pgrs_speedinit(data);
 }
 
@@ -339,6 +340,17 @@ void Curl_pgrsStartNow(struct Curl_easy *data)
   p->ul_size_known = FALSE;
 }
 
+/* this counts how much data is delivered to the application, which
+   in compressed cases may differ from downloaded amount */
+CURLcode Curl_pgrs_deliver_inc(struct Curl_easy *data, size_t delta)
+{
+  if(data->set.max_filesize &&
+     (data->progress.deliver + (curl_off_t)delta > data->set.max_filesize))
+    return CURLE_FILESIZE_EXCEEDED;
+  data->progress.deliver += delta;
+  return CURLE_OK;
+}
+
 void Curl_pgrs_download_inc(struct Curl_easy *data, size_t delta)
 {
   if(delta) {

lib/progress.h

@@ -50,7 +50,7 @@ int Curl_pgrsDone(struct Curl_easy *data);
 void Curl_pgrsStartNow(struct Curl_easy *data);
 void Curl_pgrsSetDownloadSize(struct Curl_easy *data, curl_off_t size);
 void Curl_pgrsSetUploadSize(struct Curl_easy *data, curl_off_t size);
-
+CURLcode Curl_pgrs_deliver_inc(struct Curl_easy *data, size_t delta);
 void Curl_pgrs_download_inc(struct Curl_easy *data, size_t delta);
 void Curl_pgrs_upload_inc(struct Curl_easy *data, size_t delta);
 void Curl_pgrsSetUploadCounter(struct Curl_easy *data, curl_off_t size);

lib/urldata.h

@@ -796,6 +796,7 @@ struct Progress {
                       force redraw at next call */
   struct pgrs_dir ul;
   struct pgrs_dir dl;
+  curl_off_t deliver; /* amount of data delivered to application */
 
   curl_off_t current_speed; /* uses the currently fastest transfer */
   curl_off_t earlydata_sent;