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-rw-r--r--dnsname.cc493
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diff --git a/dnsname.cc b/dnsname.cc
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+/*
+ * This file is part of PowerDNS or dnsdist.
+ * Copyright -- PowerDNS.COM B.V. and its contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * In addition, for the avoidance of any doubt, permission is granted to
+ * link this program with OpenSSL and to (re)distribute the binaries
+ * produced as the result of such linking.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "dnsname.hh"
+#include <boost/format.hpp>
+#include <string>
+#include <cinttypes>
+
+#include "dnswriter.hh"
+#include "misc.hh"
+
+#include <boost/functional/hash.hpp>
+
+const DNSName g_rootdnsname("."), g_wildcarddnsname("*");
+
+/* raw storage
+ in DNS label format, with trailing 0. W/o trailing 0, we are 'empty'
+ www.powerdns.com = 3www8powerdns3com0
+*/
+
+std::ostream & operator<<(std::ostream &os, const DNSName& d)
+{
+ return os <<d.toLogString();
+}
+
+DNSName::DNSName(const char* p, size_t length)
+{
+ if(p[0]==0 || (p[0]=='.' && p[1]==0)) {
+ d_storage.assign(1, (char)0);
+ } else {
+ if(!strchr(p, '\\')) {
+ unsigned char lenpos=0;
+ unsigned char labellen=0;
+ size_t plen=length;
+ const char* const pbegin=p, *pend=p+plen;
+ d_storage.reserve(plen+1);
+ for(auto iter = pbegin; iter != pend; ) {
+ lenpos = d_storage.size();
+ if(*iter=='.')
+ throw std::runtime_error("Found . in wrong position in DNSName "+string(p));
+ d_storage.append(1, (char)0);
+ labellen=0;
+ auto begiter=iter;
+ for(; iter != pend && *iter!='.'; ++iter) {
+ labellen++;
+ }
+ d_storage.append(begiter,iter);
+ if(iter != pend)
+ ++iter;
+ if(labellen > 63)
+ throw std::range_error("label too long to append");
+
+ if(iter-pbegin > 254) // reserve two bytes, one for length and one for the root label
+ throw std::range_error("name too long to append");
+
+ d_storage[lenpos]=labellen;
+ }
+ d_storage.append(1, (char)0);
+ }
+ else {
+ d_storage=segmentDNSNameRaw(p, length);
+ if(d_storage.size() > 255) {
+ throw std::range_error("name too long");
+ }
+ }
+ }
+}
+
+
+DNSName::DNSName(const char* pos, int len, int offset, bool uncompress, uint16_t* qtype, uint16_t* qclass, unsigned int* consumed, uint16_t minOffset)
+{
+ if (offset >= len)
+ throw std::range_error("Trying to read past the end of the buffer ("+std::to_string(offset)+ " >= "+std::to_string(len)+")");
+
+ if(!uncompress) {
+ if(const void * fnd=memchr(pos+offset, 0, len-offset)) {
+ d_storage.reserve(2+(const char*)fnd-(pos+offset));
+ }
+ }
+
+ packetParser(pos, len, offset, uncompress, qtype, qclass, consumed, 0, minOffset);
+}
+
+// this should be the __only__ dns name parser in PowerDNS.
+void DNSName::packetParser(const char* qpos, int len, int offset, bool uncompress, uint16_t* qtype, uint16_t* qclass, unsigned int* consumed, int depth, uint16_t minOffset)
+{
+ const unsigned char* pos=(const unsigned char*)qpos;
+ unsigned char labellen;
+ const unsigned char *opos = pos;
+
+ if (offset >= len)
+ throw std::range_error("Trying to read past the end of the buffer ("+std::to_string(offset)+ " >= "+std::to_string(len)+")");
+ if (offset < (int) minOffset)
+ throw std::range_error("Trying to read before the beginning of the buffer ("+std::to_string(offset)+ " < "+std::to_string(minOffset)+")");
+
+ const unsigned char* end = pos + len;
+ pos += offset;
+ while((labellen=*pos++) && pos < end) { // "scan and copy"
+ if(labellen >= 0xc0) {
+ if(!uncompress)
+ throw std::range_error("Found compressed label, instructed not to follow");
+
+ labellen &= (~0xc0);
+ int newpos = (labellen << 8) + *(const unsigned char*)pos;
+
+ if(newpos < offset) {
+ if(newpos < (int) minOffset)
+ throw std::range_error("Invalid label position during decompression ("+std::to_string(newpos)+ " < "+std::to_string(minOffset)+")");
+ if (++depth > 100)
+ throw std::range_error("Abort label decompression after 100 redirects");
+ packetParser((const char*)opos, len, newpos, true, nullptr, nullptr, nullptr, depth, minOffset);
+ } else
+ throw std::range_error("Found a forward reference during label decompression");
+ pos++;
+ break;
+ } else if(labellen & 0xc0) {
+ throw std::range_error("Found an invalid label length in qname (only one of the first two bits is set)");
+ }
+ if (pos + labellen < end) {
+ appendRawLabel((const char*)pos, labellen);
+ }
+ else
+ throw std::range_error("Found an invalid label length in qname");
+ pos+=labellen;
+ }
+ if(d_storage.empty())
+ d_storage.append(1, (char)0); // we just parsed the root
+ if(consumed)
+ *consumed = pos - opos - offset;
+ if(qtype) {
+ if (pos + 2 > end) {
+ throw std::range_error("Trying to read qtype past the end of the buffer ("+std::to_string((pos - opos) + 2)+ " > "+std::to_string(len)+")");
+ }
+ *qtype=(*(const unsigned char*)pos)*256 + *((const unsigned char*)pos+1);
+ }
+ pos+=2;
+ if(qclass) {
+ if (pos + 2 > end) {
+ throw std::range_error("Trying to read qclass past the end of the buffer ("+std::to_string((pos - opos) + 2)+ " > "+std::to_string(len)+")");
+ }
+ *qclass=(*(const unsigned char*)pos)*256 + *((const unsigned char*)pos+1);
+ }
+}
+
+std::string DNSName::toString(const std::string& separator, const bool trailing) const
+{
+ std::string ret;
+ toString(ret, separator, trailing);
+ return ret;
+}
+
+void DNSName::toString(std::string& output, const std::string& separator, const bool trailing) const
+{
+ if (empty()) {
+ throw std::out_of_range("Attempt to print an unset dnsname");
+ }
+
+ if (isRoot()) {
+ output += (trailing ? separator : "");
+ return;
+ }
+
+ if (output.capacity() < (output.size() + d_storage.size())) {
+ output.reserve(output.size() + d_storage.size());
+ }
+
+ {
+ // iterate over the raw labels
+ const char* p = d_storage.c_str();
+ const char* end = p + d_storage.size();
+
+ while (p < end && *p) {
+ appendEscapedLabel(output, p + 1, static_cast<size_t>(*p));
+ output += separator;
+ p += *p + 1;
+ }
+ }
+
+ if (!trailing) {
+ output.resize(output.size() - separator.size());
+ }
+}
+
+std::string DNSName::toLogString() const
+{
+ if (empty()) {
+ return "(empty)";
+ }
+
+ return toStringRootDot();
+}
+
+std::string DNSName::toDNSString() const
+{
+ if (empty())
+ throw std::out_of_range("Attempt to DNSString an unset dnsname");
+
+ return std::string(d_storage.c_str(), d_storage.length());
+}
+
+std::string DNSName::toDNSStringLC() const
+{
+ auto result = toDNSString();
+ toLowerInPlace(result); // label lengths are always < 'A'
+ return result;
+}
+
+/**
+ * Get the length of the DNSName on the wire
+ *
+ * @return the total wirelength of the DNSName
+ */
+size_t DNSName::wirelength() const {
+ return d_storage.length();
+}
+
+// Are WE part of parent
+bool DNSName::isPartOf(const DNSName& parent) const
+{
+ if(parent.empty() || empty())
+ throw std::out_of_range("empty dnsnames aren't part of anything");
+
+ if(parent.d_storage.size() > d_storage.size())
+ return false;
+
+ // this is slightly complicated since we can't start from the end, since we can't see where a label begins/ends then
+ for(auto us=d_storage.cbegin(); us<d_storage.cend(); us+=*us+1) {
+ auto distance = std::distance(us,d_storage.cend());
+ if (distance < 0 || static_cast<size_t>(distance) < parent.d_storage.size()) {
+ break;
+ }
+ if (static_cast<size_t>(distance) == parent.d_storage.size()) {
+ auto p = parent.d_storage.cbegin();
+ for(; us != d_storage.cend(); ++us, ++p) {
+ if(dns_tolower(*p) != dns_tolower(*us))
+ return false;
+ }
+ return true;
+ }
+ if (*us < 0) {
+ throw std::out_of_range("negative label length in dnsname");
+ }
+ }
+ return false;
+}
+
+DNSName DNSName::makeRelative(const DNSName& zone) const
+{
+ DNSName ret(*this);
+ ret.makeUsRelative(zone);
+ return ret;
+}
+
+void DNSName::makeUsRelative(const DNSName& zone)
+{
+ if (isPartOf(zone)) {
+ d_storage.erase(d_storage.size()-zone.d_storage.size());
+ d_storage.append(1, (char)0); // put back the trailing 0
+ }
+ else
+ clear();
+}
+
+DNSName DNSName::getCommonLabels(const DNSName& other) const
+{
+ DNSName result;
+
+ const std::vector<std::string> ours = getRawLabels();
+ const std::vector<std::string> others = other.getRawLabels();
+
+ for (size_t pos = 0; ours.size() > pos && others.size() > pos; pos++) {
+ const std::string& ourLabel = ours.at(ours.size() - pos - 1);
+ const std::string& otherLabel = others.at(others.size() - pos - 1);
+
+ if (!pdns_iequals(ourLabel, otherLabel)) {
+ break;
+ }
+
+ result.prependRawLabel(ourLabel);
+ }
+
+ return result;
+}
+
+DNSName DNSName::labelReverse() const
+{
+ DNSName ret;
+
+ if(isRoot())
+ return *this; // we don't create the root automatically below
+
+ if (!empty()) {
+ vector<string> l=getRawLabels();
+ while(!l.empty()) {
+ ret.appendRawLabel(l.back());
+ l.pop_back();
+ }
+ }
+ return ret;
+}
+
+void DNSName::appendRawLabel(const std::string& label)
+{
+ appendRawLabel(label.c_str(), label.length());
+}
+
+void DNSName::appendRawLabel(const char* start, unsigned int length)
+{
+ if(length==0)
+ throw std::range_error("no such thing as an empty label to append");
+ if(length > 63)
+ throw std::range_error("label too long to append");
+ if(d_storage.size() + length > 254) // reserve one byte for the label length
+ throw std::range_error("name too long to append");
+
+ if(d_storage.empty()) {
+ d_storage.append(1, (char)length);
+ }
+ else {
+ *d_storage.rbegin()=(char)length;
+ }
+ d_storage.append(start, length);
+ d_storage.append(1, (char)0);
+}
+
+void DNSName::prependRawLabel(const std::string& label)
+{
+ if(label.empty())
+ throw std::range_error("no such thing as an empty label to prepend");
+ if(label.size() > 63)
+ throw std::range_error("label too long to prepend");
+ if(d_storage.size() + label.size() > 254) // reserve one byte for the label length
+ throw std::range_error("name too long to prepend");
+
+ if(d_storage.empty())
+ d_storage.append(1, (char)0);
+
+ string_t prep(1, (char)label.size());
+ prep.append(label.c_str(), label.size());
+ d_storage = prep+d_storage;
+}
+
+bool DNSName::slowCanonCompare(const DNSName& rhs) const
+{
+ auto ours=getRawLabels(), rhsLabels = rhs.getRawLabels();
+ return std::lexicographical_compare(ours.rbegin(), ours.rend(), rhsLabels.rbegin(), rhsLabels.rend(), CIStringCompare());
+}
+
+vector<std::string> DNSName::getRawLabels() const
+{
+ vector<std::string> ret;
+ ret.reserve(countLabels());
+ // 3www4ds9a2nl0
+ for(const unsigned char* p = (const unsigned char*) d_storage.c_str(); p < ((const unsigned char*) d_storage.c_str()) + d_storage.size() && *p; p+=*p+1) {
+ ret.push_back({(const char*)p+1, (size_t)*p}); // XXX FIXME
+ }
+ return ret;
+}
+
+std::string DNSName::getRawLabel(unsigned int pos) const
+{
+ unsigned int currentPos = 0;
+ for(const unsigned char* p = (const unsigned char*) d_storage.c_str(); p < ((const unsigned char*) d_storage.c_str()) + d_storage.size() && *p; p+=*p+1, currentPos++) {
+ if (currentPos == pos) {
+ return std::string((const char*)p+1, (size_t)*p);
+ }
+ }
+
+ throw std::out_of_range("trying to get label at position "+std::to_string(pos)+" of a DNSName that only has "+std::to_string(currentPos)+" labels");
+}
+
+DNSName DNSName::getLastLabel() const
+{
+ DNSName ret(*this);
+ ret.trimToLabels(1);
+ return ret;
+}
+
+bool DNSName::chopOff()
+{
+ if(d_storage.empty() || d_storage[0]==0)
+ return false;
+ d_storage.erase(0, (unsigned int)d_storage[0]+1);
+ return true;
+}
+
+bool DNSName::isWildcard() const
+{
+ if(d_storage.size() < 2)
+ return false;
+ auto p = d_storage.begin();
+ return (*p == 0x01 && *++p == '*');
+}
+
+/*
+ * Returns true if the DNSName is a valid RFC 1123 hostname, this function uses
+ * a regex on the string, so it is probably best not used when speed is essential.
+ */
+bool DNSName::isHostname() const
+{
+ static Regex hostNameRegex = Regex("^(([A-Za-z0-9]([A-Za-z0-9-]*[A-Za-z0-9])?)\\.)+$");
+ return hostNameRegex.match(this->toString());
+}
+
+unsigned int DNSName::countLabels() const
+{
+ unsigned int count=0;
+ const unsigned char* p = reinterpret_cast<const unsigned char*>(d_storage.c_str());
+ const unsigned char* end = reinterpret_cast<const unsigned char*>(p + d_storage.size());
+
+ while (p < end && *p) {
+ ++count;
+ p += *p + 1;
+ }
+ return count;
+}
+
+void DNSName::trimToLabels(unsigned int to)
+{
+ while(countLabels() > to && chopOff())
+ ;
+}
+
+
+size_t hash_value(DNSName const& d)
+{
+ return d.hash();
+}
+
+void DNSName::appendEscapedLabel(std::string& appendTo, const char* orig, size_t len)
+{
+ size_t pos = 0;
+
+ while (pos < len) {
+ auto p = static_cast<uint8_t>(orig[pos]);
+ if(p=='.')
+ appendTo+="\\.";
+ else if(p=='\\')
+ appendTo+="\\\\";
+ else if(p > 0x20 && p < 0x7f)
+ appendTo.append(1, (char)p);
+ else {
+ char buf[] = "000";
+ auto got = snprintf(buf, sizeof(buf), "%03" PRIu8, p);
+ if (got < 0 || static_cast<size_t>(got) >= sizeof(buf)) {
+ throw std::runtime_error("Error, snprintf returned " + std::to_string(got) + " while escaping label " + std::string(orig, len));
+ }
+ appendTo.append(1, '\\');
+ appendTo += buf;
+ }
+ ++pos;
+ }
+}
+
+bool DNSName::has8bitBytes() const
+{
+ const auto& s = d_storage;
+ string::size_type pos = 0;
+ uint8_t length = s.at(pos);
+ while (length > 0) {
+ for (size_t idx = 0; idx < length; idx++) {
+ ++pos;
+ char c = s.at(pos);
+ if(!((c >= 'a' && c <= 'z') ||
+ (c >= 'A' && c <= 'Z') ||
+ (c >= '0' && c <= '9') ||
+ c =='-' || c == '_' || c=='*' || c=='.' || c=='/' || c=='@' || c==' ' || c=='\\' || c==':'))
+ return true;
+ }
+ ++pos;
+ length = s.at(pos);
+ }
+
+ return false;
+}
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