From 2d356ba1683d47ebbd08e9d6e4bb4acbb8729fee Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Thu, 27 Jan 2011 13:59:11 +0100
Subject: [PATCH] ares_query_completed_cb: don't touch invalid data

When this callback is called due to the destruction of the ares handle,
the connection pointer passed in as an argument may no longer pointing
to valid data and this function doesn't need to do anything with it
anyway so we make sure it doesn't.

Bug: http://curl.haxx.se/mail/lib-2011-01/0333.html
Reported by: Vsevolod Novikov
---
 lib/hostares.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/hostares.c b/lib/hostares.c
index 8b1dc06a7..a165cb91f 100644
--- a/lib/hostares.c
+++ b/lib/hostares.c
@@ -332,8 +332,17 @@ static void ares_query_completed_cb(void *arg,  /* (struct connectdata *) */
   (void)timeouts; /* ignored */
 #endif
 
-  if (status == CURL_ASYNC_SUCCESS) {
+  switch(status) {
+  case CURL_ASYNC_SUCCESS:
     ai = Curl_he2ai(hostent, conn->async.port);
+    break;
+  case ARES_EDESTRUCTION:
+    /* this ares handle is getting destroyed, the 'arg' pointer may not be
+       valid! */
+    return;
+  default:
+    /* do nothing */
+    break;
   }
 
   (void)Curl_addrinfo_callback(arg, status, ai);