Adding HTTP Digest Auth (but not yet enabled)

1 files changed, 527 insertions, 0 deletions

diff --git a/contrib/epee/src/http_auth.cpp b/contrib/epee/src/http_auth.cpp
new file mode 100644
index 000000000..98870a7a9
--- /dev/null
+++ b/contrib/epee/src/http_auth.cpp
@@ -0,0 +1,527 @@
+// Copyright (c) 2014-2016, 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/http_auth.h"
+
+#include <array>
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/fusion/adapted/std_tuple.hpp>
+#include <boost/fusion/algorithm/iteration/for_each.hpp>
+#include <boost/fusion/algorithm/query/any.hpp>
+#include <boost/range/algorithm/copy.hpp>
+#include <boost/range/algorithm/find_if.hpp>
+#include <boost/range/iterator_range_core.hpp>
+#include <boost/range/join.hpp>
+#include <boost/spirit/include/qi_alternative.hpp>
+#include <boost/spirit/include/qi_and_predicate.hpp>
+#include <boost/spirit/include/qi_char.hpp>
+#include <boost/spirit/include/qi_char_class.hpp>
+#include <boost/spirit/include/qi_difference.hpp>
+#include <boost/spirit/include/qi_kleene.hpp>
+#include <boost/spirit/include/qi_optional.hpp>
+#include <boost/spirit/include/qi_parse.hpp>
+#include <boost/spirit/include/qi_plus.hpp>
+#include <boost/spirit/include/qi_no_case.hpp>
+#include <boost/spirit/include/qi_raw.hpp>
+#include <boost/spirit/include/qi_rule.hpp>
+#include <boost/spirit/include/qi_sequence.hpp>
+#include <boost/spirit/include/qi_string.hpp>
+#include <boost/spirit/include/qi_symbols.hpp>
+#include <boost/spirit/include/qi_uint.hpp>
+#include <boost/utility/string_ref.hpp>
+#include <cassert>
+#include <functional>
+#include <iterator>
+#include <tuple>
+#include <type_traits>
+
+#include "crypto/crypto.h"
+#include "md5_l.h"
+#include "string_coding.h"
+
+/* This file uses the `u8` prefix and specifies all chars by ASCII numeric
+value. This is for maximum portability - C++ does not actually specify ASCII
+as the encoding type for unprefixed string literals, etc. Although rare, the
+effort required to support rare compiler encoding types is low.
+
+Also be careful of qi::ascii character classes (`qi::asci::alpha`, etc.) -
+non-ASCII characters will cause undefined behavior in the table lookup until
+boost 1.60. The expression `&qi::ascii::char_` will fail on non-ASCII
+characters without "consuming" the input character. */
+
+namespace
+{
+  // string_ref is only constexpr if length is given
+  template<std::size_t N>
+  constexpr boost::string_ref ceref(const char (&arg)[N])
+  {
+    return boost::string_ref(arg, N - 1);
+  }
+
+  constexpr const auto auth_realm = ceref(u8"monero-wallet-rpc");
+  constexpr const char comma = 44;
+  constexpr const char equal_sign = 61;
+  constexpr const char quote = 34;
+  constexpr const auto sess_algo = ceref(u8"-sess");
+
+  //// Digest Algorithms
+
+  template<std::size_t N>
+  std::array<char, N * 2> to_hex(const std::array<std::uint8_t, N>& digest) noexcept
+  {
+    static constexpr const char alphabet[] = u8"0123456789abcdef";
+    static_assert(sizeof(alphabet) == 17, "bad alphabet size");
+
+    // TODO upgrade (improve performance) of to hex in epee string tools
+    std::array<char, N * 2> out{{}};
+    auto current = out.begin();
+    for (const std::uint8_t byte : digest)
+    {
+      *current = alphabet[byte >> 4];
+      ++current;
+      *current = alphabet[byte & 0x0F];
+      ++current;
+    }
+    return out;
+  }
+
+  struct md5_
+  {
+    static constexpr const boost::string_ref name = ceref(u8"MD5");
+
+    struct update
+    {
+      template<typename T>
+      void operator()(const T& arg) const
+      {
+        const boost::iterator_range<const char*> data(boost::as_literal(arg));
+        md5::MD5Update(
+          std::addressof(ctx),
+          reinterpret_cast<const std::uint8_t*>(data.begin()),
+          data.size()
+        );
+      }
+      void operator()(const std::string& arg) const
+      {
+        (*this)(boost::string_ref(arg));
+      }
+
+      md5::MD5_CTX& ctx;
+    };
+
+    template<typename... T>
+    std::array<char, 32> operator()(const T&... args) const
+    {      
+      md5::MD5_CTX ctx{};
+      md5::MD5Init(std::addressof(ctx));
+      boost::fusion::for_each(std::tie(args...), update{ctx});
+
+      std::array<std::uint8_t, 16> digest{{}};
+      md5::MD5Final(digest.data(), std::addressof(ctx));
+      return to_hex(digest);
+    }
+  };
+  constexpr const boost::string_ref md5_::name;
+
+  //! Digest Algorithms available for HTTP Digest Auth.
+  constexpr const std::tuple<md5_> digest_algorithms{};
+
+  //// Various String Parsing Utilities
+
+  struct ascii_tolower_
+  {
+    template<typename Char>
+    Char operator()(Char value) const noexcept
+    {
+      static_assert(std::is_integral<Char>::value, "only integral types supported");
+      return (65 <= value && value <= 90) ? (value + 32) : value;
+    }
+  };
+  constexpr const ascii_tolower_ ascii_tolower{};
+
+  struct ascii_iequal_
+  {
+    template<typename Char>
+    bool operator()(Char left, Char right) const noexcept
+    {
+      return ascii_tolower(left) == ascii_tolower(right);
+    }
+  };
+  constexpr const ascii_iequal_ ascii_iequal{};
+
+  //// Digest Authentication
+  
+  struct auth_request
+  {
+    using iterator = const char*;
+    enum status{ kFail = 0, kStale, kPass };
+
+    static status verify(const std::string& method, const std::string& request,
+      const epee::net_utils::http::http_auth::session& user)
+    {
+      struct parser
+      {
+        using field_parser = std::function<bool(const parser&, iterator&, iterator, auth_request&)>;
+
+        explicit parser() : field_table(), skip_whitespace(), header(), token(), fields() {
+          using namespace std::placeholders;
+          namespace qi = boost::spirit::qi;
+
+          struct parse_nc
+          {
+            bool operator()(const parser&, iterator& current, const iterator end, auth_request& result) const
+            {
+              return qi::parse(
+                current, end,
+                (qi::raw[qi::uint_parser<std::uint32_t, 16, 8, 8>{}]),
+                result.nc
+              );
+            }
+          };
+          struct parse_token
+          {
+            bool operator()(const parser& parse, iterator& current, const iterator end,
+              boost::iterator_range<iterator>& result) const
+            {
+              return qi::parse(current, end, parse.token, result);
+            }
+          };
+          struct parse_string
+          {
+            bool operator()(const parser&, iterator& current, const iterator end,
+              boost::iterator_range<iterator>& result) const
+            {
+              return qi::parse(
+                current, end,
+                (qi::lit(quote) >> qi::raw[+(u8"\\\"" | (qi::ascii::char_ - quote))] >> qi::lit(quote)),
+                result
+              );
+            }
+          };
+          struct parse_response
+          {
+            bool operator()(const parser&, iterator& current, const iterator end, auth_request& result) const
+            {
+              using byte = qi::uint_parser<std::uint8_t, 16, 2, 2>;
+              return qi::parse(
+                current, end,
+                (qi::lit(quote) >> qi::raw[+(byte{})] >> qi::lit(quote)),
+                result.response
+              );
+            }
+          };
+
+          field_table.add
+            (u8"algorithm", std::bind(parse_token{}, _1, _2, _3, std::bind(&auth_request::algorithm, _4)))
+            (u8"cnonce", std::bind(parse_string{}, _1, _2, _3, std::bind(&auth_request::cnonce, _4)))
+            (u8"nc", parse_nc{})
+            (u8"nonce", std::bind(parse_string{}, _1, _2, _3, std::bind(&auth_request::nonce, _4)))
+            (u8"qop", std::bind(parse_token{}, _1, _2, _3, std::bind(&auth_request::qop, _4)))
+            (u8"realm", std::bind(parse_string{}, _1, _2, _3, std::bind(&auth_request::realm, _4)))
+            (u8"response", parse_response{})
+            (u8"uri", std::bind(parse_string{}, _1, _2, _3, std::bind(&auth_request::uri, _4)))
+            (u8"username", std::bind(parse_string{}, _1, _2, _3, std::bind(&auth_request::username, _4)));
+
+          skip_whitespace = *(&qi::ascii::char_ >> qi::ascii::space);
+          header = skip_whitespace >> qi::ascii::no_case[u8"digest"] >> skip_whitespace;
+          token =
+            -qi::lit(quote) >>
+            qi::raw[+(&qi::ascii::char_ >> (qi::ascii::graph - qi::ascii::char_(u8"()<>@,;:\\\"/[]?={}")))] >>
+            -qi::lit(quote);
+          fields = field_table >> skip_whitespace >> equal_sign >> skip_whitespace;
+        }
+
+        boost::optional<auth_request> operator()(const std::string& method, const std::string& request) const
+        { 
+          namespace qi = boost::spirit::qi;
+           
+          iterator current = request.data();
+          const iterator end = current + request.size();
+
+          if (!qi::parse(current, end, header))
+          {
+            return boost::none;
+          }
+
+          auth_request info(method);
+          field_parser null_parser{};
+          std::reference_wrapper<const field_parser> field = null_parser;
+
+          do // require at least one field; require field after `,` character
+          {
+            if (!qi::parse(current, end, fields, field) || !field(*this, current, end, info))
+            {
+              return boost::none;
+            }
+            qi::parse(current, end, skip_whitespace);
+          } while (qi::parse(current, end, qi::char_(comma) >> skip_whitespace));
+          return boost::make_optional(current == end, info);
+        }
+
+      private:
+        boost::spirit::qi::symbols<
+          char, field_parser, boost::spirit::qi::tst<char, field_parser>, ascii_tolower_
+        > field_table;
+        boost::spirit::qi::rule<iterator> skip_whitespace;
+        boost::spirit::qi::rule<iterator> header;
+        boost::spirit::qi::rule<iterator, boost::iterator_range<iterator>()> token;
+        boost::spirit::qi::rule<iterator, std::reference_wrapper<const field_parser>()> fields;
+      }; // parser
+
+      static const parser parse;
+      return do_verify(parse(method, request), user);
+    }
+
+  private:
+    explicit auth_request(const std::string& method_)
+      : algorithm()
+      , cnonce()
+      , method(method_)
+      , nc()
+      , nonce()
+      , qop()
+      , realm()
+      , response()
+      , uri()
+      , username() {
+    }
+
+    struct has_valid_response
+    {
+      template<typename Digest, typename Result>
+      Result generate_old_response(Digest digest, const Result& key, const Result& auth) const
+      {
+        return digest(key, u8":", request.nonce, u8":", auth);
+      }
+
+      template<typename Digest, typename Result>
+      Result generate_new_response(Digest digest, const Result& key, const Result& auth) const
+      {
+        return digest(
+          key, u8":", request.nonce, u8":", request.nc, u8":", request.cnonce, u8":", request.qop, u8":", auth
+        );
+      }
+
+      template<typename Digest>
+      typename std::result_of<Digest()>::type generate_auth(Digest digest) const
+      {
+        return digest(request.method, u8":", request.uri);
+      }
+
+      template<typename Result>
+      bool check(const Result& result) const
+      {
+        return boost::equals(request.response, result, ascii_iequal);
+      }
+
+      template<typename Digest>
+      bool operator()(const Digest& digest) const
+      {
+        if (boost::starts_with(request.algorithm, Digest::name, ascii_iequal) ||
+            (request.algorithm.empty() && std::is_same<md5_, Digest>::value))
+        {
+          auto key = digest(user.credentials.username, u8":", auth_realm, u8":", user.credentials.password);
+
+          if (boost::ends_with(request.algorithm, sess_algo, ascii_iequal))
+          {
+            key = digest(key, u8":", request.nonce, u8":", request.cnonce);
+          }
+
+          if (request.qop.empty())
+          {
+            return check(generate_old_response(digest, std::move(key), generate_auth(digest)));
+          }
+          else if (boost::equals(ceref(u8"auth"), request.qop, ascii_iequal))
+          {
+            return check(generate_new_response(digest, std::move(key), generate_auth(digest)));
+          }
+        }
+        return false;
+      }
+
+      const auth_request& request;
+      const epee::net_utils::http::http_auth::session& user;
+    };
+
+    static status do_verify(const boost::optional<auth_request>& request,
+      const epee::net_utils::http::http_auth::session& user)
+    {
+      if (request && 
+          boost::equals(request->username, user.credentials.username) &&
+          boost::fusion::any(digest_algorithms, has_valid_response{*request, user}))
+      {
+        if (boost::equals(request->nonce, user.nonce))
+        {
+          // RFC 2069 format does not verify nc value - allow just once
+          if (user.counter == 1 || (!request->qop.empty() && request->counter() == user.counter))
+          {
+            return kPass;
+          }
+        }
+        return kStale;
+      }
+      return kFail;
+    }
+
+    boost::optional<std::uint32_t> counter() const
+    {
+      namespace qi = boost::spirit::qi;
+      using hex = qi::uint_parser<std::uint32_t, 16>;
+      std::uint32_t value = 0;
+      const bool converted = qi::parse(nc.begin(), nc.end(), hex{}, value);
+      return boost::make_optional(converted, value);
+    }
+
+    boost::iterator_range<iterator> algorithm;
+    boost::iterator_range<iterator> cnonce;
+    boost::string_ref method;
+    boost::iterator_range<iterator> nc;
+    boost::iterator_range<iterator> nonce;
+    boost::iterator_range<iterator> qop;
+    boost::iterator_range<iterator> realm;
+    boost::iterator_range<iterator> response;
+    boost::iterator_range<iterator> uri;
+    boost::iterator_range<iterator> username; 
+  }; // auth_request
+
+  struct add_challenge
+  {
+    template<typename T>
+    static void add_field(std::string& str, const char* const name, const T& value)
+    {
+      str.push_back(comma);
+      str.append(name);
+      str.push_back(equal_sign);
+      boost::range::copy(value, std::back_inserter(str));
+    }
+
+    template<typename T>
+    using quoted_result = boost::joined_range<
+      const boost::joined_range<const boost::string_ref, const T>, const boost::string_ref
+    >;
+
+    template<typename T>
+    static quoted_result<T> quoted(const T& arg)
+    {
+      return boost::range::join(boost::range::join(ceref(u8"\""), arg), ceref(u8"\""));
+    }
+
+    template<typename Digest>
+    void operator()(const Digest& digest) const
+    {
+      static constexpr const auto fname = ceref(u8"WWW-authenticate");
+      static constexpr const auto fvalue = ceref(u8"Digest qop=\"auth\"");
+
+      for (unsigned i = 0; i < 2; ++i)
+      {
+        std::string out(fvalue);
+
+        const auto algorithm = boost::range::join(
+          Digest::name, (i == 0 ? boost::string_ref{} : sess_algo)
+        );
+        add_field(out, u8"algorithm", algorithm);
+        add_field(out, u8"realm", quoted(auth_realm));
+        add_field(out, u8"nonce", quoted(nonce));
+        add_field(out, u8"stale", is_stale ? ceref("true") : ceref("false"));
+        
+        fields.push_back(std::make_pair(std::string(fname), std::move(out)));
+      }
+    }
+
+    const std::string& nonce;
+    std::list<std::pair<std::string, std::string>>& fields;
+    const bool is_stale;
+  };
+
+  epee::net_utils::http::http_response_info create_digest_response(
+    const std::string& nonce, const bool is_stale)
+  {
+    epee::net_utils::http::http_response_info rc{};
+    rc.m_response_code = 401;
+    rc.m_response_comment = u8"Unauthorized";
+    rc.m_mime_tipe = u8"text/html";
+    rc.m_body = 
+      u8"<html><head><title>Unauthorized Access</title></head><body><h1>401 Unauthorized</h1></body></html>";
+
+    boost::fusion::for_each(
+      digest_algorithms, add_challenge{nonce, rc.m_additional_fields, is_stale}
+    );
+    
+    return rc;
+  }
+}
+
+namespace epee
+{
+  namespace net_utils
+  {
+    namespace http
+    {
+      http_auth::http_auth(login credentials)
+        : user(session{std::move(credentials)}) {
+      }
+
+      boost::optional<http_response_info> http_auth::process(const http_request_info& request)
+      {
+        assert(user);
+        using field = std::pair<std::string, std::string>;
+
+        const std::list<field>& fields = request.m_header_info.m_etc_fields;
+        const auto auth = boost::find_if(fields, [] (const field& value) {
+          return boost::equals(ceref(u8"authorization"), value.first, ascii_iequal);
+        });
+
+        bool is_stale = false;
+        if (auth != fields.end())
+        {
+          ++(user->counter);
+          switch (auth_request::verify(request.m_http_method_str, auth->second, *user))
+          {
+          case auth_request::kPass:
+            return boost::none;
+
+          case auth_request::kStale:
+            is_stale = true;
+            break;
+
+          default:
+          case auth_request::kFail:
+            break;
+          }
+        }
+        user->counter = 0;
+        {
+          std::array<std::uint8_t, 16> rand_128bit{{}};
+          crypto::rand(rand_128bit.size(), rand_128bit.data());
+          user->nonce = string_encoding::base64_encode(rand_128bit.data(), rand_128bit.size());
+        }
+        return create_digest_response(user->nonce, is_stale);
+      }
+    }
+  }
+}
+