From: Amos Jeffries <squid3@treenet.co.nz>
Date: Fri, 6 May 2016 09:39:48 +0000 (+1200)
Subject: Fix SIGSEGV in ESIContext response handling
X-Git-Tag: SQUID_3_5_18~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e5f4f9b31e1a05d1bacfb8a18b1792c7ef2bcf4a;p=thirdparty%2Fsquid.git

Fix SIGSEGV in ESIContext response handling

HttpReply pointer was being unlocked without heving been locked.
Resulting in a double-free. Make it use RefCount instead of
manual locking to ensure locked/unlock is always symmetrical.
---

diff --git a/src/esi/Context.h b/src/esi/Context.h
index ea6abc1940..1f02bca462 100644
--- a/src/esi/Context.h
+++ b/src/esi/Context.h
@@ -13,6 +13,7 @@
 #include "err_type.h"
 #include "esi/Element.h"
 #include "esi/Parser.h"
+#include "HttpReply.h"
 #include "http/StatusCode.h"
 
 class ESIVarState;
@@ -91,7 +92,7 @@ public:
     err_type errorpage; /* if we error what page to use */
     Http::StatusCode errorstatus; /* if we error, what code to return */
     char *errormessage; /* error to pass to error page */
-    HttpReply *rep; /* buffered until we pass data downstream */
+    HttpReply::Pointer rep; /* buffered until we pass data downstream */
     ESISegment::Pointer buffered; /* unprocessed data - for whatever reason */
     ESISegment::Pointer incoming;
     /* processed data we are waiting to send, or for
diff --git a/src/esi/Esi.cc b/src/esi/Esi.cc
index 29f36ee544..994e8e85cf 100644
--- a/src/esi/Esi.cc
+++ b/src/esi/Esi.cc
@@ -573,7 +573,7 @@ ESIContext::send ()
 
 #endif
 
-    if (!(rep || (outbound.getRaw() &&
+    if (!(rep != NULL || (outbound.getRaw() &&
                   outbound->len && (outbound_offset <= outbound->len)))) {
         debugs(86, 5, "ESIContext::send: Nothing to send.");
         return 0;
@@ -618,18 +618,18 @@ ESIContext::send ()
     flags.clientwantsdata = 0;
     debugs(86, 5, "ESIContext::send: this=" << this << " Client no longer wants data ");
     /* Deal with re-entrancy */
-    HttpReply *temprep = rep;
+    HttpReply::Pointer temprep = rep;
     rep = NULL; /* freed downstream */
 
-    if (temprep && varState)
-        varState->buildVary (temprep);
+    if (temprep != NULL && varState)
+        varState->buildVary(temprep.getRaw());
 
     {
         StoreIOBuffer tempBuffer;
         tempBuffer.length = len;
         tempBuffer.offset = pos - len;
         tempBuffer.data = next->readBuffer.data;
-        clientStreamCallback (thisNode, http, temprep, tempBuffer);
+        clientStreamCallback (thisNode, http, temprep.getRaw(), tempBuffer);
     }
 
     if (len == 0)
@@ -1259,7 +1259,7 @@ ESIContext::parse()
         ++parserState.stackdepth;
     }
 
-    if (rep && !parserState.inited())
+    if (rep != NULL && !parserState.inited())
         parserState.init(this);
 
     /* we have data */
@@ -1398,7 +1398,7 @@ ESIContext::freeResources ()
 {
     debugs(86, 5, HERE << "Freeing for this=" << this);
 
-    HTTPMSGUNLOCK(rep);
+    rep = NULL; // refcounted
 
     finishChildren ();