From 46576178a3e3566f2a43b337eb279266bf98f9aa Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Sun, 14 Oct 2018 22:57:54 +0900
Subject: [PATCH] Don't send Transfer-Encoding to pre-HTTP/1.1 clients

---
 src/http2.cc                            | 9 +++++++++
 src/http2.h                             | 7 +++++++
 src/shrpx_http_downstream_connection.cc | 5 +++++
 src/shrpx_https_upstream.cc             | 8 ++++++--
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/http2.cc b/src/http2.cc
index 566cfb00..74360a50 100644
--- a/src/http2.cc
+++ b/src/http2.cc
@@ -503,6 +503,11 @@ void build_http1_headers_from_headers(DefaultMemchunks *buf,
         continue;
       }
       break;
+    case HD_TRANSFER_ENCODING:
+      if (flags & HDOP_STRIP_TRANSFER_ENCODING) {
+        continue;
+      }
+      break;
     case HD_FORWARDED:
       if (flags & HDOP_STRIP_FORWARDED) {
         continue;
@@ -1874,6 +1879,10 @@ StringRef make_websocket_accept_token(uint8_t *dest, const StringRef &key) {
   return StringRef{dest, end};
 }
 
+bool legacy_http1(int major, int minor) {
+  return major <= 0 || (major == 1 && minor == 0);
+}
+
 } // namespace http2
 
 } // namespace nghttp2
diff --git a/src/http2.h b/src/http2.h
index 9e7d7491..5b8ef284 100644
--- a/src/http2.h
+++ b/src/http2.h
@@ -217,6 +217,9 @@ enum HeaderBuildOp {
   // Sec-WebSocket-Key header field must be stripped.  If this flag is
   // not set, all Sec-WebSocket-Key header fields are added.
   HDOP_STRIP_SEC_WEBSOCKET_KEY = 1 << 6,
+  // Transfer-Encoding header field must be stripped.  If this flag is
+  // not set, all Transfer-Encoding header fields are added.
+  HDOP_STRIP_TRANSFER_ENCODING = 1 << 7,
 };
 
 // Appends headers in |headers| to |nv|.  |headers| must be indexed
@@ -437,6 +440,10 @@ bool contains_trailers(const StringRef &s);
 // of error.
 StringRef make_websocket_accept_token(uint8_t *dest, const StringRef &key);
 
+// Returns true if HTTP version represents pre-HTTP/1.1 (e.g.,
+// HTTP/0.9 or HTTP/1.0).
+bool legacy_http1(int major, int minor);
+
 } // namespace http2
 
 } // namespace nghttp2
diff --git a/src/shrpx_http_downstream_connection.cc b/src/shrpx_http_downstream_connection.cc
index 31f48a24..50d8634c 100644
--- a/src/shrpx_http_downstream_connection.cc
+++ b/src/shrpx_http_downstream_connection.cc
@@ -1000,6 +1000,11 @@ int htp_hdrs_completecb(http_parser *htp) {
     resp.connection_close = true;
     // transfer-encoding not applied to upgraded connection
     downstream->set_chunked_response(false);
+  } else if (http2::legacy_http1(req.http_major, req.http_minor)) {
+    if (resp.fs.content_length == -1) {
+      resp.connection_close = true;
+    }
+    downstream->set_chunked_response(false);
   } else if (!downstream->expect_response_body()) {
     downstream->set_chunked_response(false);
   }
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index b6953a76..d4e8538c 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -1122,8 +1122,12 @@ int HttpsUpstream::on_downstream_header_complete(Downstream *downstream) {
     return 0;
   }
 
-  http2::build_http1_headers_from_headers(
-      buf, resp.fs.headers(), http2::HDOP_STRIP_ALL & ~http2::HDOP_STRIP_VIA);
+  auto build_flags = (http2::HDOP_STRIP_ALL & ~http2::HDOP_STRIP_VIA) |
+                     (!http2::legacy_http1(req.http_major, req.http_minor)
+                          ? 0
+                          : http2::HDOP_STRIP_TRANSFER_ENCODING);
+
+  http2::build_http1_headers_from_headers(buf, resp.fs.headers(), build_flags);
 
   auto worker = handler_->get_worker();