Merged revisions 201380 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r201380 | dbrooks | 2009-06-17 13:45:50 -0500 (Wed, 17 Jun 2009) | 9 lines
  
  Checks for NULL sip_pvt pointer in chan_sip.c->acf_channel_read()
  
  Zombie channels could be passed, and chan_sip.c wasn't checking for it.
  Could crash Asterisk. Now checking for NULL pointer.
  
  (closes issue #15330)
  Reported by: okrief
  Tested by: dbrooks
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@201381 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -21046,6 +21046,10 @@ static int acf_channel_read(struct ast_channel *chan, const char *funcname, char
 
 	memset(buf, 0, buflen);
 
+	if (p == NULL) {
+		return -1;
+	}
+
 	if (!strcasecmp(args.param, "peerip")) {
 		ast_copy_string(buf, p->sa.sin_addr.s_addr ? ast_inet_ntoa(p->sa.sin_addr) : "", buflen);
 	} else if (!strcasecmp(args.param, "recvip")) {