content_encoding: do not reset stage counter for each header

Test 418 verifies

Closes #10492

lib/content_encoding.c

@@ -1047,7 +1047,6 @@ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
                                      const char *enclist, int is_transfer)
 {
   struct SingleRequest *k = &data->req;
-  int counter = 0;
   unsigned int order = is_transfer? 2: 1;
 
   do {
@@ -1084,9 +1083,9 @@ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data,
       if(!encoding)
         encoding = &error_encoding;  /* Defer error at stack use. */
 
-      if(++counter >= MAX_ENCODE_STACK) {
-        failf(data, "Reject response due to %u content encodings",
-              counter);
+      if(k->writer_stack_depth++ >= MAX_ENCODE_STACK) {
+        failf(data, "Reject response due to more than %u content encodings",
+              MAX_ENCODE_STACK);
         return CURLE_BAD_CONTENT_ENCODING;
       }
       /* Stack the unencoding stage. */

lib/urldata.h

@@ -689,6 +689,7 @@ struct SingleRequest {
   struct dohdata *doh; /* DoH specific data for this request */
 #endif
   unsigned char setcookies;
+  unsigned char writer_stack_depth; /* Unencoding stack depth. */
   BIT(header);        /* incoming data has HTTP header */
   BIT(content_range); /* set TRUE if Content-Range: was found */
   BIT(upload_done);   /* set to TRUE when doing chunked transfer-encoding

tests/data/Makefile.inc

@@ -68,7 +68,7 @@ test380 test381 test383 test384 test385 test386 test387 test388 test389 \
 test390 test391 test392 test393 test394 test395 test396 test397 test398 \
 test399 test400 test401 test402 test403 test404 test405 test406 test407 \
 test408 test409 test410 test411 test412 test413 test414 test415 test416 \
-test417 \
+test417 test418 \
 \
 test430 test431 test432 test433 test434 test435 test436 \
 \

tests/data/test387

@@ -47,7 +47,7 @@ Accept: */*
 61
 </errorcode>
 <stderr mode="text">
-curl: (61) Reject response due to 5 content encodings
+curl: (61) Reject response due to more than 5 content encodings
 </stderr>
 </verify>
 </testcase>

tests/data/test418

@@ -0,0 +1,152 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+gzip
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+HTTP/1.1 200 OK
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+Transfer-Encoding: gzip
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+Response with multiple Transfer-Encoding headers
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER -sS
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes">
+GET /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+</protocol>
+
+# CURLE_BAD_CONTENT_ENCODING is 61
+<errorcode>
+61
+</errorcode>
+<stderr mode="text">
+curl: (61) Reject response due to more than 5 content encodings
+</stderr>
+</verify>
+</testcase>