nghttpx: Validate received response body length against content-length

src/shrpx_downstream.cc

@@ -109,9 +109,10 @@ Downstream::Downstream(Upstream *upstream, int32_t stream_id, int32_t priority)
     : request_buf_(upstream ? upstream->get_mcpool() : nullptr),
       response_buf_(upstream ? upstream->get_mcpool() : nullptr),
       request_bodylen_(0), response_bodylen_(0), response_sent_bodylen_(0),
-      upstream_(upstream), request_headers_sum_(0), response_headers_sum_(0),
-      request_datalen_(0), response_datalen_(0), stream_id_(stream_id),
-      priority_(priority), downstream_stream_id_(-1),
+      response_content_length_(-1), upstream_(upstream),
+      request_headers_sum_(0), response_headers_sum_(0), request_datalen_(0),
+      response_datalen_(0), stream_id_(stream_id), priority_(priority),
+      downstream_stream_id_(-1),
       response_rst_stream_error_code_(NGHTTP2_NO_ERROR),
       request_state_(INITIAL), request_major_(1), request_minor_(1),
       response_state_(INITIAL), response_http_status_(0), response_major_(1),
@@ -663,6 +664,24 @@ int64_t Downstream::get_response_sent_bodylen() const {
   return response_sent_bodylen_;
 }
 
+void Downstream::set_response_content_length(int64_t len) {
+  response_content_length_ = len;
+}
+
+bool Downstream::validate_response_bodylen() const {
+  if (!expect_response_body() || response_content_length_ == -1) {
+    return true;
+  }
+
+  if (LOG_ENABLED(INFO)) {
+    DLOG(INFO, this) << "response invalid bodylen: content-length="
+                     << response_content_length_
+                     << ", received=" << response_bodylen_;
+  }
+
+  return response_content_length_ == response_bodylen_;
+}
+
 void Downstream::set_priority(int32_t pri) { priority_ = pri; }
 
 int32_t Downstream::get_priority() const { return priority_; }
@@ -719,6 +738,14 @@ void Downstream::inspect_http1_response() {
       util::strifind(response_headers_[idx].value.c_str(), "chunked")) {
     chunked_response_ = true;
   }
+
+  idx = response_hdidx_[http2::HD_CONTENT_LENGTH];
+  if (idx != -1) {
+    auto len = util::parse_uint(response_headers_[idx].value);
+    if (len != -1) {
+      response_content_length_ = len;
+    }
+  }
 }
 
 void Downstream::reset_response() {

src/shrpx_downstream.h

@@ -218,6 +218,10 @@ public:
   int64_t get_response_bodylen() const;
   void add_response_sent_bodylen(size_t amount);
   int64_t get_response_sent_bodylen() const;
+  void set_response_content_length(int64_t len);
+  // Validates that received response body length and content-length
+  // matches.
+  bool validate_response_bodylen() const;
   uint32_t get_response_rst_stream_error_code() const;
   void set_response_rst_stream_error_code(uint32_t error_code);
   // Inspects HTTP/1 response.  This checks tranfer-encoding etc.
@@ -297,13 +301,17 @@ private:
   ev_timer downstream_rtimer_;
   ev_timer downstream_wtimer_;
 
-  // the length of request body
+  // the length of request body received so far
   int64_t request_bodylen_;
-  // the length of response body
+  // the length of response body received so far
   int64_t response_bodylen_;
+
   // the length of response body sent to upstream client
   int64_t response_sent_bodylen_;
 
+  // content-length of response body, -1 if it is unknown.
+  int64_t response_content_length_;
+
   Upstream *upstream_;
   std::unique_ptr<DownstreamConnection> dconn_;
 

src/shrpx_http2_session.cc

@@ -817,23 +817,24 @@ int on_response_headers(Http2Session *http2session, Downstream *downstream,
     return 0;
   }
 
-  auto content_length =
+  auto content_length_hd =
       downstream->get_response_header(http2::HD_CONTENT_LENGTH);
-  if (!content_length && downstream->get_request_method() != "HEAD" &&
-      downstream->get_request_method() != "CONNECT") {
-    unsigned int status;
-    status = downstream->get_response_http_status();
-    if (!((100 <= status && status <= 199) || status == 204 || status == 304)) {
-      // Here we have response body but Content-Length is not known
-      // in advance.
+
+  if (content_length_hd) {
+    auto content_length = util::parse_uint(content_length_hd->value);
+    if (content_length != -1) {
+      downstream->set_response_content_length(content_length);
+    } else if (downstream->expect_response_body()) {
+      // Here we have response body but Content-Length is not known in
+      // advance.
       if (downstream->get_request_major() <= 0 ||
           downstream->get_request_minor() <= 0) {
         // We simply close connection for pre-HTTP/1.1 in this case.
         downstream->set_response_connection_close(true);
-      } else {
-        // Otherwise, use chunked encoding to keep upstream
-        // connection open.  In HTTP2, we are supporsed not to
-        // receive transfer-encoding.
+      } else if (downstream->get_request_method() != "CONNECT") {
+        // Otherwise, use chunked encoding to keep upstream connection
+        // open.  In HTTP2, we are supporsed not to receive
+        // transfer-encoding.
         downstream->add_response_header("transfer-encoding", "chunked");
         downstream->set_chunked_response(true);
       }

src/shrpx_http2_upstream.cc

@@ -526,7 +526,9 @@ int on_frame_not_send_callback(nghttp2_session *session,
                        << ", lib_error_code=" << lib_error_code << ":"
                        << nghttp2_strerror(lib_error_code);
   if (frame->hd.type == NGHTTP2_HEADERS &&
-      frame->headers.cat == NGHTTP2_HCAT_RESPONSE) {
+      frame->headers.cat == NGHTTP2_HCAT_RESPONSE &&
+      lib_error_code != NGHTTP2_ERR_STREAM_CLOSED &&
+      lib_error_code != NGHTTP2_ERR_STREAM_CLOSING) {
     // To avoid stream hanging around, issue RST_STREAM.
     auto downstream = upstream->find_downstream(frame->hd.stream_id);
     if (downstream) {
@@ -1207,6 +1209,13 @@ int Http2Upstream::on_downstream_body_complete(Downstream *downstream) {
   if (LOG_ENABLED(INFO)) {
     DLOG(INFO, downstream) << "HTTP response completed";
   }
+
+  if (!downstream->validate_response_bodylen()) {
+    rst_stream(downstream, NGHTTP2_PROTOCOL_ERROR);
+    downstream->set_response_connection_close(true);
+    return 0;
+  }
+
   nghttp2_session_resume_data(session_, downstream->get_stream_id());
   downstream->ensure_upstream_wtimer();
 

src/shrpx_https_upstream.cc

@@ -768,6 +768,10 @@ int HttpsUpstream::on_downstream_body_complete(Downstream *downstream) {
     DLOG(INFO, downstream) << "HTTP response completed";
   }
 
+  if (!downstream->validate_response_bodylen()) {
+    downstream->set_response_connection_close(true);
+  }
+
   if (downstream->get_request_connection_close() ||
       downstream->get_response_connection_close()) {
     auto handler = get_client_handler();

src/shrpx_spdy_upstream.cc

@@ -336,7 +336,8 @@ void on_ctrl_not_send_callback(spdylay_session *session,
   ULOG(WARN, upstream) << "Failed to send control frame type=" << type
                        << ", error_code=" << error_code << ":"
                        << spdylay_strerror(error_code);
-  if (type == SPDYLAY_SYN_REPLY) {
+  if (type == SPDYLAY_SYN_REPLY && error_code != SPDYLAY_ERR_STREAM_CLOSED &&
+      error_code != SPDYLAY_ERR_STREAM_CLOSING) {
     // To avoid stream hanging around, issue RST_STREAM.
     auto stream_id = frame->syn_reply.stream_id;
     auto downstream = upstream->find_downstream(stream_id);
@@ -917,6 +918,12 @@ int SpdyUpstream::on_downstream_body_complete(Downstream *downstream) {
     DLOG(INFO, downstream) << "HTTP response completed";
   }
 
+  if (!downstream->validate_response_bodylen()) {
+    rst_stream(downstream, SPDYLAY_PROTOCOL_ERROR);
+    downstream->set_response_connection_close(true);
+    return 0;
+  }
+
   spdylay_session_resume_data(session_, downstream->get_stream_id());
   downstream->ensure_upstream_wtimer();
 

src/util.cc

@@ -954,6 +954,10 @@ int64_t parse_uint(const char *s) {
   return parse_uint(reinterpret_cast<const uint8_t *>(s), strlen(s));
 }
 
+int64_t parse_uint(const std::string &s) {
+  return parse_uint(reinterpret_cast<const uint8_t *>(s.c_str()), s.size());
+}
+
 int64_t parse_uint(const uint8_t *s, size_t len) {
   if (len == 0) {
     return -1;

src/util.h

@@ -506,6 +506,7 @@ int64_t parse_uint_with_unit(const char *s);
 // the parsed integer.  If there is an error, returns -1.
 int64_t parse_uint(const char *s);
 int64_t parse_uint(const uint8_t *s, size_t len);
+int64_t parse_uint(const std::string &s);
 
 } // namespace util