From c492a313ce2893fdb8d5f1215b95d437a00c92de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Dimitrov?= <peterdmv@erlang.org>
Date: Tue, 21 Aug 2018 09:25:28 +0200
Subject: inets: Do not use chunked encoding with 1xx, 204, 304

All 1xx (informational), 204 (no content), and 304 (not modified)
responses MUST NOT include a message-body, and thus are always
terminated by the first empty line after the header fields.
This implies that chunked encoding MUST NOT be used for these
status codes.

Change-Id: If6778165c947e64bc20d1ecab7a669e0b096f1a9
---
 lib/inets/src/http_server/httpd_example.erl |  8 +++++-
 lib/inets/src/http_server/mod_esi.erl       | 15 +++++++++---
 lib/inets/test/httpd_SUITE.erl              | 38 ++++++++++++++++++++++++++++-
 3 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/lib/inets/src/http_server/httpd_example.erl b/lib/inets/src/http_server/httpd_example.erl
index 47a8c48d01..dbf7c44ad3 100644
--- a/lib/inets/src/http_server/httpd_example.erl
+++ b/lib/inets/src/http_server/httpd_example.erl
@@ -22,7 +22,7 @@
 -export([print/1]).
 -export([get/2, put/2, post/2, yahoo/2, test1/2, get_bin/2, peer/2,new_status_and_location/2]).
 
--export([newformat/3, post_chunked/3]).
+-export([newformat/3, post_chunked/3, post_204/3]).
 %% These are used by the inets test-suite
 -export([delay/1, chunk_timeout/3]).
 
@@ -151,6 +151,12 @@ post_chunked(SessionID, _Env, {last, _Body, undefined} = _Bodychunk) ->
 post_chunked(_, _, _Body) ->
     exit(body_not_chunked).
 
+post_204(SessionID, _Env, _Input) ->
+    mod_esi:deliver(SessionID,
+                    ["Status: 204 No Content" ++ "\r\n\r\n"]),
+    mod_esi:deliver(SessionID, []).
+
+
 newformat(SessionID,_,_) ->
     mod_esi:deliver(SessionID, "Content-Type:text/html\r\n\r\n"),
     mod_esi:deliver(SessionID, top("new esi format test")),
diff --git a/lib/inets/src/http_server/mod_esi.erl b/lib/inets/src/http_server/mod_esi.erl
index 3206d957d9..9fbedce6aa 100644
--- a/lib/inets/src/http_server/mod_esi.erl
+++ b/lib/inets/src/http_server/mod_esi.erl
@@ -394,7 +394,16 @@ deliver_webpage_chunk(#mod{config_db = Db} = ModData, Pid, Timeout) ->
             Continue;
 	{Headers, Body} ->
             {ok, NewHeaders, StatusCode} = httpd_esi:handle_headers(Headers),
-                IsDisableChunkedSend = httpd_response:is_disable_chunked_send(Db),
+            %% All 1xx (informational), 204 (no content), and 304 (not modified)
+            %% responses MUST NOT include a message-body, and thus are always
+            %% terminated by the first empty line after the header fields.
+            %% This implies that chunked encoding MUST NOT be used for these
+            %% status codes.
+            IsDisableChunkedSend =
+                httpd_response:is_disable_chunked_send(Db) orelse
+                StatusCode =:= 204 orelse                      %% No Content
+                StatusCode =:= 304 orelse                      %% Not Modified
+                (100 =< StatusCode andalso StatusCode =< 199), %% Informational
             case (ModData#mod.http_version =/= "HTTP/1.1") or
                 (IsDisableChunkedSend) of
                 true ->
@@ -405,8 +414,8 @@ deliver_webpage_chunk(#mod{config_db = Db} = ModData, Pid, Timeout) ->
                     send_headers(ModData, StatusCode, 
                                  [{"transfer-encoding", 
                                    "chunked"} | NewHeaders])
-            end,    
-            handle_body(Pid, ModData, Body, Timeout, length(Body), 
+            end,
+            handle_body(Pid, ModData, Body, Timeout, length(Body),
                         IsDisableChunkedSend);
         timeout ->
             send_headers(ModData, 504, [{"connection", "close"}]),
diff --git a/lib/inets/test/httpd_SUITE.erl b/lib/inets/test/httpd_SUITE.erl
index 95466887f9..90192e633c 100644
--- a/lib/inets/test/httpd_SUITE.erl
+++ b/lib/inets/test/httpd_SUITE.erl
@@ -118,7 +118,7 @@ groups() ->
 		   disturbing_1_0, 
 		   disturbing_0_9
 		  ]},
-     {post, [], [chunked_post, chunked_chunked_encoded_post]},
+     {post, [], [chunked_post, chunked_chunked_encoded_post, post_204]},
      {basic_auth, [], [basic_auth_1_1, basic_auth_1_0, basic_auth_0_9]},
      {auth_api, [], [auth_api_1_1, auth_api_1_0, auth_api_0_9
 		    ]},
@@ -746,6 +746,42 @@ chunked_chunked_encoded_post(Config) when is_list(Config) ->
                      [{http_version, "HTTP/1.1"} | Config], 
                      [{statuscode, 200}]).
 
+%%-------------------------------------------------------------------------
+post_204() ->
+    [{doc,"Test that 204 responses are not chunk encoded"}].
+post_204(Config) ->
+    Host = proplists:get_value(host, Config),
+    Port =  proplists:get_value(port, Config),
+    SockType = proplists:get_value(type, Config),
+    TranspOpts = transport_opts(SockType, Config),
+    Request = "POST /cgi-bin/erl/httpd_example:post_204 ",
+
+    try inets_test_lib:connect_bin(SockType, Host, Port, TranspOpts) of
+	{ok, Socket} ->
+            RequestStr = http_request(Request, "HTTP/1.1", Host),
+	    ok = inets_test_lib:send(SockType, Socket, RequestStr),
+            receive
+                {tcp, Socket, Data} ->
+                    case binary:match(Data, <<"chunked">>,[]) of
+                        nomatch ->
+                            ok;
+                        {_, _} ->
+                            ct:fail("Chunked encoding detected.")
+                    end
+            after 2000 ->
+                    ct:fail(connection_timed_out)
+            end;
+	ConnectError ->
+	    ct:fail({connect_error, ConnectError,
+		     [SockType, Host, Port, TranspOpts]})
+    catch
+	T:E ->
+	    ct:fail({connect_failure,
+		     [{type,       T},
+		      {error,      E},
+		      {stacktrace, erlang:get_stacktrace()},
+		      {args,       [SockType, Host, Port, TranspOpts]}]})
+    end.
 
 %%-------------------------------------------------------------------------
 htaccess_1_1(Config) when is_list(Config) -> 
-- 
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