From c1ec990a37d22342c48ad5f541f1d3204d7fd864 Mon Sep 17 00:00:00 2001
From: "Alan M. Carroll" <amc@apache.org>
Date: Thu, 30 Jul 2020 15:50:16 -0500
Subject: [PATCH] Move the direct self loop check later to
 HttpSM::do_http_server_open just before connection upstream. This closed
 #7052

---
 proxy/http/HttpSM.cc       |  6 ++++++
 proxy/http/HttpTransact.cc | 22 ++++++++++------------
 proxy/http/HttpTransact.h  |  2 +-
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/proxy/http/HttpSM.cc b/proxy/http/HttpSM.cc
index db0fc62debf..ae4b5a03adf 100644
--- a/proxy/http/HttpSM.cc
+++ b/proxy/http/HttpSM.cc
@@ -4938,6 +4938,12 @@ HttpSM::do_http_server_open(bool raw)
     }
   }
 
+  // Check for self loop.
+  if (HttpTransact::will_this_request_self_loop(&t_state)) {
+    call_transact_and_set_next_state(HttpTransact::SelfLoop);
+    return;
+  }
+
   // If this is not a raw connection, we try to get a session from the
   //  shared session pool.  Raw connections are for SSLs tunnel and
   //  require a new connection
diff --git a/proxy/http/HttpTransact.cc b/proxy/http/HttpTransact.cc
index d7e90ba95cc..ef7781dfd90 100644
--- a/proxy/http/HttpTransact.cc
+++ b/proxy/http/HttpTransact.cc
@@ -845,6 +845,16 @@ HttpTransact::Forbidden(State *s)
   TRANSACT_RETURN(SM_ACTION_SEND_ERROR_CACHE_NOOP, nullptr);
 }
 
+void
+HttpTransact::SelfLoop(State *s)
+{
+  TxnDebug("http_trans", "[Loop]"
+                         "Request will selfloop.");
+  bootstrap_state_variables_from_request(s, &s->hdr_info.client_request);
+  build_error_response(s, HTTP_STATUS_BAD_REQUEST, "Direct self loop detected", "request#cycle_detected");
+  TRANSACT_RETURN(SM_ACTION_SEND_ERROR_CACHE_NOOP, nullptr);
+}
+
 void
 HttpTransact::TooEarly(State *s)
 {
@@ -1856,17 +1866,6 @@ HttpTransact::OSDNSLookup(State *s)
     TRANSACT_RETURN(SM_ACTION_SEND_ERROR_CACHE_NOOP, nullptr);
   }
 
-  // detect whether we are about to self loop. the client may have
-  // specified the proxy as the origin server (badness).
-  // Check if this procedure is already done - YTS Team, yamsat
-  if (!s->request_will_not_selfloop) {
-    if (will_this_request_self_loop(s)) {
-      TxnDebug("http_trans", "[OSDNSLookup] request will selfloop - bailing out");
-      SET_VIA_STRING(VIA_DETAIL_TUNNEL, VIA_DETAIL_TUNNEL_NO_FORWARD);
-      TRANSACT_RETURN(SM_ACTION_SEND_ERROR_CACHE_NOOP, nullptr);
-    }
-  }
-
   if (!s->dns_info.lookup_success) {
     // maybe the name can be expanded (e.g cnn -> www.cnn.com)
     HostNameExpansionError_t host_name_expansion = try_to_expand_host_name(s);
@@ -6640,7 +6639,6 @@ HttpTransact::will_this_request_self_loop(State *s)
       via_field = via_field->m_next_dup;
     }
   }
-  s->request_will_not_selfloop = true;
   return false;
 }
 
diff --git a/proxy/http/HttpTransact.h b/proxy/http/HttpTransact.h
index de80411cf51..df7986a4588 100644
--- a/proxy/http/HttpTransact.h
+++ b/proxy/http/HttpTransact.h
@@ -686,7 +686,6 @@ class HttpTransact
     bool force_dns                        = false;
     MgmtByte cache_open_write_fail_action = 0;
     bool is_revalidation_necessary        = false; // Added to check if revalidation is necessary - YTS Team, yamsat
-    bool request_will_not_selfloop        = false; // To determine if process done - YTS Team, yamsat
     ConnectionAttributes client_info;
     ConnectionAttributes parent_info;
     ConnectionAttributes server_info;
@@ -939,6 +938,7 @@ class HttpTransact
   static void BadRequest(State *s);
   static void Forbidden(State *s);
   static void TooEarly(State *s);
+  static void SelfLoop(State *s);
   static void PostActiveTimeoutResponse(State *s);
   static void PostInactiveTimeoutResponse(State *s);
   static void DecideCacheLookup(State *s);