/*

* (C) 2014,2015,2017 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/asn1_print.h>

#include <botan/bigint.h>

#include <botan/hex.h>

#include <botan/der_enc.h>

#include <botan/ber_dec.h>

#include <botan/oids.h>

#include <iomanip>

#include <sstream>

#include <cctype>

namespace Botan {

namespace {

bool all_printable_chars(const uint8_t bits[], size_t bits_len)

   {

   for(size_t i = 0; i != bits_len; ++i)

      {

      int c = bits[i];

      if(c > 127)

         return false;

      if((std::isalnum(c) || c == '.' || c == ':' || c == '/' || c == '-') == false)

         return false;

      }

   return true;

   }

/*

* Special hack to handle GeneralName [2] and [6] (DNS name and URI)

*/

bool possibly_a_general_name(const uint8_t bits[], size_t bits_len)

   {

   if(bits_len <= 2)

      return false;

   if(bits[0] != 0x82 && bits[0] != 0x86)

      return false;

   if(bits[1] != bits_len - 2)

      return false;

   if(all_printable_chars(bits + 2, bits_len - 2) == false)

      return false;

   return true;

   }

}

std::string ASN1_Formatter::print(const uint8_t in[], size_t len) const

   {

   std::ostringstream output;

   print_to_stream(output, in, len);

   return output.str();

   }

void ASN1_Formatter::print_to_stream(std::ostream& output,

                                     const uint8_t in[],

                                     size_t len) const

   {

   BER_Decoder dec(in, len);

   decode(output, dec, 0);

   }

void ASN1_Formatter::decode(std::ostream& output,

                            BER_Decoder& decoder,

                            size_t level) const

   {

   BER_Object obj = decoder.get_next_object();

   const bool recurse_deeper = (m_max_depth == 0 || level < m_max_depth);

   while(obj.is_set())

      {

      const ASN1_Tag type_tag = obj.type();

      const ASN1_Tag class_tag = obj.get_class();

      const size_t length = obj.length();

      /* hack to insert the tag+length back in front of the stuff now

         that we've gotten the type info */

      std::vector<uint8_t> bits;

      DER_Encoder(bits).add_object(type_tag, class_tag, obj.bits(), obj.length());

      BER_Decoder data(bits);

      if(class_tag & CONSTRUCTED)

         {

         BER_Decoder cons_info(obj.bits(), obj.length());

         if(recurse_deeper)

            {

            output << format(type_tag, class_tag, level, length, "");

            decode(output, cons_info, level + 1); // recurse

            }

         else

            {

            output << format(type_tag, class_tag, level, length,

                             format_bin(type_tag, class_tag, bits));

            }

         }

      else if((class_tag & APPLICATION) || (class_tag & CONTEXT_SPECIFIC))

         {

         bool success_parsing_cs = false;

         if(m_print_context_specific)

            {

            try

               {

               if(possibly_a_general_name(bits.data(), bits.size()))

                  {

                  output << format(type_tag, class_tag, level, level,

                                   std::string(cast_uint8_ptr_to_char(&bits[2]), bits.size() - 2));

                  success_parsing_cs = true;

                  }

               else if(recurse_deeper)

                  {

                  std::vector<uint8_t> inner_bits;

                  data.decode(inner_bits, type_tag);

                  BER_Decoder inner(inner_bits);

                  std::ostringstream inner_data;

                  decode(inner_data, inner, level + 1); // recurse

                  output << inner_data.str();

                  success_parsing_cs = true;

                  }

               }

            catch(...)

               {

               }

            }

         if(success_parsing_cs == false)

            {

            output << format(type_tag, class_tag, level, length,

                             format_bin(type_tag, class_tag, bits));

            }

         }

      else if(type_tag == OBJECT_ID)

         {

         OID oid;

         data.decode(oid);

         std::string out = OIDS::oid2str_or_empty(oid);

         if(out.empty())

            {

            out = oid.to_string();

            }

         else

            {

            out += " [" + oid.to_string() + "]";

            }

         output << format(type_tag, class_tag, level, length, out);

         }

      else if(type_tag == INTEGER || type_tag == ENUMERATED)

         {

         BigInt number;

         if(type_tag == INTEGER)

            {

            data.decode(number);

            }

         else if(type_tag == ENUMERATED)

            {

            data.decode(number, ENUMERATED, class_tag);

            }

         std::vector<uint8_t> rep = BigInt::encode(number);

         if(rep.empty()) // if zero

            rep.resize(1);

         output << format(type_tag, class_tag, level, length, hex_encode(rep));

         }

      else if(type_tag == BOOLEAN)

         {

         bool boolean;

         data.decode(boolean);

         output << format(type_tag, class_tag, level, length, (boolean ? "true" : "false"));

         }

      else if(type_tag == NULL_TAG)

         {

         output << format(type_tag, class_tag, level, length, "");

         }

      else if(type_tag == OCTET_STRING || type_tag == BIT_STRING)

         {

         std::vector<uint8_t> decoded_bits;

         data.decode(decoded_bits, type_tag);

         bool printing_octet_string_worked = false;

         if(recurse_deeper)

            {

            try

               {

               BER_Decoder inner(decoded_bits);

               std::ostringstream inner_data;

               decode(inner_data, inner, level + 1); // recurse

               output << format(type_tag, class_tag, level, length, "");

               output << inner_data.str();

               printing_octet_string_worked = true;

               }

            catch(...)

               {

               }

            }

         if(!printing_octet_string_worked)

            {

            output << format(type_tag, class_tag, level, length,

                             format_bin(type_tag, class_tag, decoded_bits));

            }

         }

      else if(ASN1_String::is_string_type(type_tag))

         {

         ASN1_String str;

         data.decode(str);

         output << format(type_tag, class_tag, level, length, str.value());

         }

      else if(type_tag == UTC_TIME || type_tag == GENERALIZED_TIME)

         {

         ASN1_Time time;

         data.decode(time);

         output << format(type_tag, class_tag, level, length, time.readable_string());

         }

      else

         {

         output << "Unknown ASN.1 tag class=" << static_cast<int>(class_tag)

                << " type=" << static_cast<int>(type_tag) << "\n";

         }

      obj = decoder.get_next_object();

      }

   }

namespace {

std::string format_type(ASN1_Tag type_tag, ASN1_Tag class_tag)

   {

   if(class_tag == UNIVERSAL)

      return asn1_tag_to_string(type_tag);

   if(class_tag == CONSTRUCTED && (type_tag == SEQUENCE || type_tag == SET))

      return asn1_tag_to_string(type_tag);

   std::string name;

   if(class_tag & CONSTRUCTED)

      name += "cons ";

   name += "[" + std::to_string(type_tag) + "]";

   if(class_tag & APPLICATION)

      {

      name += " appl";

      }

   if(class_tag & CONTEXT_SPECIFIC)

      {

      name += " context";

      }

   return name;

   }

}

std::string ASN1_Pretty_Printer::format(ASN1_Tag type_tag,

                                        ASN1_Tag class_tag,

                                        size_t level,

                                        size_t length,

                                        const std::string& value) const

   {

   bool should_skip = false;

   if(value.length() > m_print_limit)

      {

      should_skip = true;

      }

   if((type_tag == OCTET_STRING || type_tag == BIT_STRING) &&

      value.length() > m_print_binary_limit)

      {

      should_skip = true;

      }

   level += m_initial_level;

   std::ostringstream oss;

   oss << "  d=" << std::setw(2) << level

       << ", l=" << std::setw(4) << length << ":"

       << std::string(level + 1, ' ') << format_type(type_tag, class_tag);

   if(value != "" && !should_skip)

      {

      const size_t current_pos = static_cast<size_t>(oss.tellp());

      const size_t spaces_to_align =

         (current_pos >= m_value_column) ? 1 : (m_value_column - current_pos);

      oss << std::string(spaces_to_align, ' ') << value;

      }

   oss << "\n";

   return oss.str();

   }

std::string ASN1_Pretty_Printer::format_bin(ASN1_Tag /*type_tag*/,

                                            ASN1_Tag /*class_tag*/,

                                            const std::vector<uint8_t>& vec) const

   {

   if(all_printable_chars(vec.data(), vec.size()))

      {

      return std::string(cast_uint8_ptr_to_char(vec.data()), vec.size());

      }

   else

      return hex_encode(vec);

   }

}