chunked-encoding: stop hiding the CURLE_BAD_CONTENT_ENCODING error

Unknown content-encoding would get returned as CURLE_WRITE_ERROR if the
response is chunked-encoded.

Reported-by: Ilya Kosarev
Fixes #4310
Closes #4449

lib/http.h

@@ -83,11 +83,6 @@ CURLcode Curl_http(struct connectdata *conn, bool *done);
 CURLcode Curl_http_done(struct connectdata *, CURLcode, bool premature);
 CURLcode Curl_http_connect(struct connectdata *conn, bool *done);
 
-/* The following functions are defined in http_chunks.c */
-void Curl_httpchunk_init(struct connectdata *conn);
-CHUNKcode Curl_httpchunk_read(struct connectdata *conn, char *datap,
-                              ssize_t length, ssize_t *wrote);
-
 /* These functions are in http.c */
 CURLcode Curl_http_input_auth(struct connectdata *conn, bool proxy,
                               const char *auth);

lib/http_chunks.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2019, 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
@@ -109,7 +109,8 @@ void Curl_httpchunk_init(struct connectdata *conn)
 CHUNKcode Curl_httpchunk_read(struct connectdata *conn,
                               char *datap,
                               ssize_t datalen,
-                              ssize_t *wrotep)
+                              ssize_t *wrotep,
+                              CURLcode *extrap)
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data = conn->data;
@@ -125,8 +126,10 @@ CHUNKcode Curl_httpchunk_read(struct connectdata *conn,
      chunk read process, to properly calculate the content length*/
   if(data->set.http_te_skip && !k->ignorebody) {
     result = Curl_client_write(conn, CLIENTWRITE_BODY, datap, datalen);
-    if(result)
+    if(result) {
-      return CHUNKE_WRITE_ERROR;
+      *extrap = result;
+      return CHUNKE_PASSTHRU_ERROR;
+    }
   }
 
   while(length) {
@@ -197,8 +200,10 @@ CHUNKcode Curl_httpchunk_read(struct connectdata *conn,
         else
           result = Curl_client_write(conn, CLIENTWRITE_BODY, datap, piece);
 
-        if(result)
+        if(result) {
-          return CHUNKE_WRITE_ERROR;
+          *extrap = result;
+          return CHUNKE_PASSTHRU_ERROR;
+        }
       }
 
       *wrote += piece;
@@ -244,8 +249,10 @@ CHUNKcode Curl_httpchunk_read(struct connectdata *conn,
           if(!data->set.http_te_skip) {
             result = Curl_client_write(conn, CLIENTWRITE_HEADER,
                                        conn->trailer, conn->trlPos);
-            if(result)
+            if(result) {
-              return CHUNKE_WRITE_ERROR;
+              *extrap = result;
+              return CHUNKE_PASSTHRU_ERROR;
+            }
           }
           conn->trlPos = 0;
           ch->state = CHUNK_TRAILER_CR;
@@ -339,8 +346,9 @@ const char *Curl_chunked_strerror(CHUNKcode code)
     return "Illegal or missing hexadecimal sequence";
   case CHUNKE_BAD_CHUNK:
     return "Malformed encoding found";
-  case CHUNKE_WRITE_ERROR:
+  case CHUNKE_PASSTHRU_ERROR:
-    return "Write error";
+    DEBUGASSERT(0); /* never used */
+    return "";
   case CHUNKE_BAD_ENCODING:
     return "Bad content-encoding found";
   case CHUNKE_OUT_OF_MEMORY:

lib/http_chunks.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2019, 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
@@ -21,6 +21,9 @@
  * KIND, either express or implied.
  *
  ***************************************************************************/
+
+struct connectdata;
+
 /*
  * The longest possible hexadecimal number we support in a chunked transfer.
  * Weird enough, RFC2616 doesn't set a maximum size! Since we use strtoul()
@@ -71,9 +74,9 @@ typedef enum {
   CHUNKE_TOO_LONG_HEX = 1,
   CHUNKE_ILLEGAL_HEX,
   CHUNKE_BAD_CHUNK,
-  CHUNKE_WRITE_ERROR,
   CHUNKE_BAD_ENCODING,
   CHUNKE_OUT_OF_MEMORY,
+  CHUNKE_PASSTHRU_ERROR, /* Curl_httpchunk_read() returns a CURLcode to use */
   CHUNKE_LAST
 } CHUNKcode;
 
@@ -87,4 +90,10 @@ struct Curl_chunker {
   size_t dataleft; /* untouched data amount at the end of the last buffer */
 };
 
+/* The following functions are defined in http_chunks.c */
+void Curl_httpchunk_init(struct connectdata *conn);
+CHUNKcode Curl_httpchunk_read(struct connectdata *conn, char *datap,
+                              ssize_t length, ssize_t *wrote,
+                              CURLcode *passthru);
+
 #endif /* HEADER_CURL_HTTP_CHUNKS_H */

lib/http_proxy.c

@@ -384,11 +384,12 @@ static CURLcode CONNECT(struct connectdata *conn,
             /* chunked-encoded body, so we need to do the chunked dance
                properly to know when the end of the body is reached */
             CHUNKcode r;
+            CURLcode extra;
             ssize_t tookcareof = 0;
 
             /* now parse the chunked piece of data so that we can
                properly tell when the stream ends */
-            r = Curl_httpchunk_read(conn, s->ptr, 1, &tookcareof);
+            r = Curl_httpchunk_read(conn, s->ptr, 1, &tookcareof, &extra);
             if(r == CHUNKE_STOP) {
               /* we're done reading chunks! */
               infof(data, "chunk reading DONE\n");
@@ -455,6 +456,7 @@ static CURLcode CONNECT(struct connectdata *conn,
             }
             else if(s->chunked_encoding) {
               CHUNKcode r;
+              CURLcode extra;
 
               infof(data, "Ignore chunked response-body\n");
 
@@ -472,7 +474,8 @@ static CURLcode CONNECT(struct connectdata *conn,
 
               /* now parse the chunked piece of data so that we can
                  properly tell when the stream ends */
-              r = Curl_httpchunk_read(conn, s->line_start + 1, 1, &gotbytes);
+              r = Curl_httpchunk_read(conn, s->line_start + 1, 1, &gotbytes,
+                                      &extra);
               if(r == CHUNKE_STOP) {
                 /* we're done reading chunks! */
                 infof(data, "chunk reading DONE\n");

lib/transfer.c

@@ -776,14 +776,14 @@ static CURLcode readwrite_data(struct Curl_easy *data,
          * and writes away the data. The returned 'nread' holds the number
          * of actual data it wrote to the client.
          */
-
+        CURLcode extra;
         CHUNKcode res =
-          Curl_httpchunk_read(conn, k->str, nread, &nread);
+          Curl_httpchunk_read(conn, k->str, nread, &nread, &extra);
 
         if(CHUNKE_OK < res) {
-          if(CHUNKE_WRITE_ERROR == res) {
+          if(CHUNKE_PASSTHRU_ERROR == res) {
-            failf(data, "Failed writing data");
+            failf(data, "Failed reading the chunked-encoded stream");
-            return CURLE_WRITE_ERROR;
+            return extra;
           }
           failf(data, "%s in chunked-encoding", Curl_chunked_strerror(res));
           return CURLE_RECV_ERROR;