m_callerid, m_dccallow Fix crash caused by allowing unregistered users and SIDs to...

[user/henk/code/inspircd.git] / src / dns.cpp

diff --git a/src/dns.cpp b/src/dns.cpp
index 21b0d9e39f400134cded6218bed3355ce71f3d75..17641c585be5de1d320c868a9c669dfc9861d2df 100644 (file)
--- a/src/dns.cpp
+++ b/src/dns.cpp
@@ -1,16 +1,27 @@
-/*       +------------------------------------+
- *       | Inspire Internet Relay Chat Daemon |
- *       +------------------------------------+
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2012 William Pitcock <nenolod@dereferenced.org>
+ *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
+ *   Copyright (C) 2006, 2009 Robin Burchell <robin+git@viroteck.net>
+ *   Copyright (C) 2007, 2009 Dennis Friis <peavey@inspircd.org>
+ *   Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
+ *   Copyright (C) 2005-2007 Craig Edwards <craigedwards@brainbox.cc>
  *
- *  InspIRCd: (C) 2002-2010 InspIRCd Development Team
- * See: http://wiki.inspircd.org/Credits
+ * This file is part of InspIRCd.  InspIRCd is free software: you can
+ * redistribute it and/or modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation, version 2.
  *
- * This program is free but copyrighted software; see
- *            the file COPYING for details.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
  *
- * ---------------------------------------------------
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+
 /* $Core */
 
 /*
@@ -100,7 +111,7 @@ class DNSRequest
 
        DNSRequest(DNS* dns, int id, const std::string &original);
        ~DNSRequest();
-       DNSInfo ResultIsReady(DNSHeader &h, int length);
+       DNSInfo ResultIsReady(DNSHeader &h, unsigned length);
        int SendRequests(const DNSHeader *header, const int length, QueryType qt);
 };
 
@@ -693,7 +704,7 @@ DNSResult DNS::GetResult()
 }
 
 /** A result is ready, process it */
-DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
+DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, unsigned length)
 {
        unsigned i = 0, o;
        int q = 0;
@@ -722,7 +733,7 @@ DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
        /* Subtract the length of the header from the length of the packet */
        length -= 12;
 
-       while ((unsigned int)q < header.qdcount && i < (unsigned) length)
+       while ((unsigned int)q < header.qdcount && i < length)
        {
                if (header.payload[i] > 63)
                {
@@ -743,7 +754,7 @@ DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
        while ((unsigned)curanswer < header.ancount)
        {
                q = 0;
-               while (q == 0 && i < (unsigned) length)
+               while (q == 0 && i < length)
                {
                        if (header.payload[i] > 63)
                        {
@@ -760,7 +771,7 @@ DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
                                else i += header.payload[i] + 1; /* skip length and label */
                        }
                }
-               if ((unsigned) length - i < 10)
+               if (static_cast<int>(length - i) < 10)
                        return std::make_pair((unsigned char*)NULL,"Incorrectly sized DNS reply");
 
                /* XXX: We actually initialise 'rr' here including its ttl field */
@@ -800,9 +811,11 @@ DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
                 */
                case DNS_QUERY_CNAME:
                case DNS_QUERY_PTR:
+               {
+                       unsigned short lowest_pos = length;
                        o = 0;
                        q = 0;
-                       while (q == 0 && i < (unsigned) length && o + 256 < 1023)
+                       while (q == 0 && i < length && o + 256 < 1023)
                        {
                                /* DN label found (byte over 63) */
                                if (header.payload[i] > 63)
@@ -812,14 +825,18 @@ DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
                                        i = ntohs(ptr);
 
                                        /* check that highest two bits are set. if not, we've been had */
-                                       if (!(i & DN_COMP_BITMASK))
+                                       if ((i & DN_COMP_BITMASK) != DN_COMP_BITMASK)
                                                return std::make_pair((unsigned char *) NULL, "DN label decompression header is bogus");
 
                                        /* mask away the two highest bits. */
                                        i &= ~DN_COMP_BITMASK;
 
                                        /* and decrease length by 12 bytes. */
-                                       i =- 12;
+                                       i -= 12;
+
+                                       if (i >= lowest_pos)
+                                               return std::make_pair((unsigned char *) NULL, "Invalid decompression pointer");
+                                       lowest_pos = i;
                                }
                                else
                                {
@@ -843,6 +860,7 @@ DNSInfo DNSRequest::ResultIsReady(DNSHeader &header, int length)
                                }
                        }
                        res[o] = 0;
+               }
                break;
                case DNS_QUERY_AAAA:
                        if (rr.rdlength != sizeof(struct in6_addr))