Add TLSA support to DNSSEC fetching

src/common/dns_utils.cpp

@@ -37,6 +37,7 @@
 #include <boost/thread/mutex.hpp>
 #include <boost/algorithm/string/join.hpp>
 #include <boost/optional.hpp>
+#include <boost/utility/string_ref.hpp>
 using namespace epee;
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
@@ -124,6 +125,7 @@ static const char *get_record_name(int record_type)
     case DNS_TYPE_A: return "A";
     case DNS_TYPE_TXT: return "TXT";
     case DNS_TYPE_AAAA: return "AAAA";
+    case DNS_TYPE_TLSA: return "TLSA";
     default: return "unknown";
   }
 }
@@ -186,6 +188,13 @@ boost::optional<std::string> txt_to_string(const char* src, size_t len)
   return std::string(src+1, len-1);
 }
 
+boost::optional<std::string> tlsa_to_string(const char* src, size_t len)
+{
+  if (len < 4)
+    return boost::none;
+  return std::string(src, len);
+}
+
 // custom smart pointer.
 // TODO: see if std::auto_ptr and the like support custom destructors
 template<typename type, void (*freefunc)(type*)>
@@ -326,11 +335,15 @@ std::vector<std::string> DNSResolver::get_record(const std::string& url, int rec
   // destructor takes care of cleanup
   ub_result_ptr result;
 
+  MDEBUG("Performing DNSSEC " << get_record_name(record_type) << " record query for " << url);
+
   // call DNS resolver, blocking.  if return value not zero, something went wrong
   if (!ub_resolve(m_data->m_ub_context, string_copy(url.c_str()), record_type, DNS_CLASS_IN, &result))
   {
     dnssec_available = (result->secure || result->bogus);
     dnssec_valid = result->secure && !result->bogus;
+    if (dnssec_available && !dnssec_valid)
+      MWARNING("Invalid DNSSEC " << get_record_name(record_type) << " record signature for " << url << ": " << result->why_bogus);
     if (result->havedata)
     {
       for (size_t i=0; result->data[i] != NULL; i++)
@@ -338,8 +351,9 @@ std::vector<std::string> DNSResolver::get_record(const std::string& url, int rec
         boost::optional<std::string> res = (*reader)(result->data[i], result->len[i]);
         if (res)
         {
-          MINFO("Found \"" << *res << "\" in " << get_record_name(record_type) << " record for " << url);
-          addresses.push_back(*res);
+          // do not dump dns record directly from dns into log
+          MINFO("Found " << get_record_name(record_type) << " record for " << url);
+          addresses.push_back(std::move(*res));
         }
       }
     }
@@ -363,6 +377,17 @@ std::vector<std::string> DNSResolver::get_txt_record(const std::string& url, boo
   return get_record(url, DNS_TYPE_TXT, txt_to_string, dnssec_available, dnssec_valid);
 }
 
+std::vector<std::string> DNSResolver::get_tlsa_tcp_record(const boost::string_ref url, const boost::string_ref port, bool& dnssec_available, bool& dnssec_valid)
+{
+  std::string service_addr;
+  service_addr.reserve(url.size() + port.size() + 7);
+  service_addr.push_back('_');
+  service_addr.append(port.data(), port.size());
+  service_addr.append("._tcp.");
+  service_addr.append(url.data(), url.size());
+  return get_record(service_addr, DNS_TYPE_TLSA, tlsa_to_string, dnssec_available, dnssec_valid);
+}
+
 std::string DNSResolver::get_dns_format_from_oa_address(const std::string& oa_addr)
 {
   std::string addr(oa_addr);

src/common/dns_utils.h

@@ -31,15 +31,17 @@
 #include <string>
 #include <functional>
 #include <boost/optional/optional_fwd.hpp>
+#include <boost/utility/string_ref_fwd.hpp>
 
 namespace tools
 {
 
 // RFC defines for record types and classes for DNS, gleaned from ldns source
-const static int DNS_CLASS_IN  = 1;
-const static int DNS_TYPE_A    = 1;
-const static int DNS_TYPE_TXT  = 16;
-const static int DNS_TYPE_AAAA = 8;
+constexpr const int DNS_CLASS_IN  = 1;
+constexpr const int DNS_TYPE_A    = 1;
+constexpr const int DNS_TYPE_TXT  = 16;
+constexpr const int DNS_TYPE_AAAA = 8;
+constexpr const int DNS_TYPE_TLSA = 52;
 
 struct DNSResolverData;
 
@@ -105,6 +107,17 @@ public:
   // TODO: modify this to accommodate DNSSEC
    std::vector<std::string> get_txt_record(const std::string& url, bool& dnssec_available, bool& dnssec_valid);
 
+  /**
+   * @brief gets all TLSA TCP records from a DNS query for the supplied URL;
+   * if no TLSA record present returns an empty vector.
+   *
+   * @param url A string containing a URL to query for
+   * @param port The service port number (as string) to query
+   *
+   * @return A vector of strings containing all TLSA records; or an empty vector
+   */
+  std::vector<std::string> get_tlsa_tcp_record(boost::string_ref url, boost::string_ref port, bool& dnssec_available, bool& dnssec_valid);
+
   /**
    * @brief Gets a DNS address from OpenAlias format
    *

src/net/CMakeLists.txt

@@ -26,10 +26,10 @@
 # STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-set(net_sources dandelionpp.cpp error.cpp http.cpp i2p_address.cpp parse.cpp socks.cpp
-    socks_connect.cpp tor_address.cpp zmq.cpp)
-set(net_headers dandelionpp.h error.h http.cpp i2p_address.h parse.h socks.h socks_connect.h
-    tor_address.h zmq.h)
+set(net_sources dandelionpp.cpp error.cpp http.cpp i2p_address.cpp parse.cpp resolve.cpp
+    socks.cpp socks_connect.cpp tor_address.cpp zmq.cpp)
+set(net_headers dandelionpp.h error.h http.cpp i2p_address.h parse.h socks.h resolve.h
+    socks_connect.h tor_address.h zmq.h)
 
 monero_add_library(net ${net_sources} ${net_headers})
 target_link_libraries(net common epee ${ZMQ_LIB} ${Boost_ASIO_LIBRARY})

src/net/error.cpp

@@ -47,12 +47,18 @@ namespace
         {
             switch (net::error(value))
             {
+            case net::error::bogus_dnssec:
+                return "Invalid response signature from DNSSEC enabled domain";
+            case net::error::dns_query_failure:
+                return "Failed to retrieve desired DNS record";
             case net::error::expected_tld:
                 return "Expected top-level domain";
             case net::error::invalid_host:
                 return "Host value is not valid";
             case net::error::invalid_i2p_address:
                 return "Invalid I2P address";
+            case net::error::invalid_mask:
+                return "CIDR netmask outside of 0-32 range";
             case net::error::invalid_port:
                 return "Invalid port value (expected 0-65535)";
             case net::error::invalid_tor_address:
@@ -71,6 +77,7 @@ namespace
             switch (net::error(value))
             {
             case net::error::invalid_port:
+            case net::error::invalid_mask:
                 return std::errc::result_out_of_range;
             case net::error::expected_tld:
             case net::error::invalid_tor_address:

src/net/error.h

@@ -37,13 +37,16 @@ namespace net
     enum class error : int
     {
         // 0 reserved for success (as per expect<T>)
-        expected_tld = 1,   //!< Expected a tld
+        bogus_dnssec = 1,   //!< Invalid response signature from DNSSEC enabled domain
+        dns_query_failure,  //!< Failed to retrieve desired DNS record
+        expected_tld,       //!< Expected a tld
         invalid_host,       //!< Hostname is not valid
         invalid_i2p_address,
+        invalid_mask,       //!< Outside of 0-32 range
         invalid_port,       //!< Outside of 0-65535 range
         invalid_tor_address,//!< Invalid base32 or length
         unsupported_address,//!< Type not supported by `get_network_address`
-        invalid_mask,       //!< Outside of 0-32 range
+
     };
 
     //! \return `std::error_category` for `net` namespace.

src/net/resolve.cpp

@@ -0,0 +1,71 @@
+// Copyright (c) 2020, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "net/resolve.h"
+
+#include <boost/utility/string_ref.hpp>
+#include "common/dns_utils.h"
+#include "common/expect.h"
+#include "net/error.h"
+
+namespace net
+{
+namespace dnssec
+{
+  expect<service_response> resolve_hostname(const std::string& addr, const std::string& tlsa_port)
+  {
+    // use basic (blocking) unbound for now, possibly refactor later
+    tools::DNSResolver& resolver = tools::DNSResolver::instance();
+
+    bool dnssec_available = false;
+    bool dnssec_valid = false;
+    std::vector<std::string> ip_records = resolver.get_ipv4(addr, dnssec_available, dnssec_valid);
+
+    if (dnssec_available && !dnssec_valid)
+      return {net::error::bogus_dnssec};
+
+    if (ip_records.empty())
+    {
+      ip_records = resolver.get_ipv6(addr, dnssec_available, dnssec_valid);
+      if (dnssec_available && !dnssec_valid)
+        return {net::error::bogus_dnssec};
+      if (ip_records.empty())
+        return {net::error::dns_query_failure};
+    }
+
+    std::vector<std::string> tlsa{};
+    if (dnssec_available && !tlsa_port.empty())
+    {
+      tlsa = resolver.get_tlsa_tcp_record(addr, tlsa_port, dnssec_available, dnssec_valid);
+      if (!dnssec_valid)
+        return {net::error::bogus_dnssec};
+    }
+    return {{std::move(ip_records), std::move(tlsa)}};
+  }
+} // dnssec
+} // net

src/net/resolve.h

@@ -0,0 +1,47 @@
+// Copyright (c) 2020, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <string>
+#include <vector>
+
+template<typename> class expect;
+
+namespace net
+{
+namespace dnssec
+{
+  struct service_response
+  {
+    std::vector<std::string> ip;   //!< IPv4/6 records in dotted or semicolon notation
+    std::vector<std::string> tlsa; //!< DANE/TLSA records
+  };
+
+  //! \return IP + (optionally) DANE/TLSA records, failing if DNSSEC signature is "bogus"
+  expect<service_response> resolve_hostname(const std::string& addr, const std::string& tlsa_port = {});
+} // dnssec
+} // net