Move ASN1 printer to the library

1 files changed, 279 insertions, 0 deletions

diff --git a/src/lib/asn1/asn1_print.cpp b/src/lib/asn1/asn1_print.cpp
new file mode 100644
index 000000000..e314b5c99
--- /dev/null
+++ b/src/lib/asn1/asn1_print.cpp
@@ -0,0 +1,279 @@
+/*
+* (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/asn1_time.h>
+#include <botan/asn1_str.h>
+#include <botan/oids.h>
+#include <iomanip>
+#include <sstream>
+#include <cctype>
+
+namespace Botan {
+
+std::string ASN1_Pretty_Printer::print(const uint8_t in[], size_t len) const
+   {
+   std::ostringstream output;
+   print_to_stream(output, in, len);
+   return output.str();
+   }
+
+void ASN1_Pretty_Printer::print_to_stream(std::ostream& output,
+                                          const uint8_t in[],
+                                          size_t len) const
+   {
+   BER_Decoder dec(in, len);
+   decode(output, dec, m_initial_level);
+   }
+
+std::string ASN1_Pretty_Printer::format_binary(const std::vector<uint8_t>& in) const
+   {
+   std::ostringstream out;
+
+   size_t unprintable = 0;
+
+   for(size_t i = 0; i != in.size(); ++i)
+      {
+      const int c = in[i];
+      if(std::isalnum(c))
+         {
+         out << static_cast<char>(c);
+         }
+      else
+         {
+         out << "%" << std::hex << static_cast<int>(c) << std::dec;
+         ++unprintable;
+         if(unprintable >= in.size() / 4)
+            {
+            return hex_encode(in);
+            }
+         }
+      }
+
+   return out.str();
+   }
+
+void ASN1_Pretty_Printer::emit(std::ostream& output,
+                               const std::string& type,
+                               size_t level, size_t length,
+                               const std::string& value) const
+   {
+   std::ostringstream oss;
+
+   oss << "  d=" << std::setw(2) << level
+       << ", l=" << std::setw(4) << length << ":"
+       << std::string(level + 1, ' ') << type;
+
+   bool should_skip = false;
+
+   if(value.length() > m_print_limit)
+      {
+      should_skip = true;
+      }
+
+   if((type == "OCTET STRING" || type == "BIT STRING") && value.length() > m_print_binary_limit)
+      {
+      should_skip = true;
+      }
+
+   const std::string s = oss.str();
+
+   output << s;
+
+   if(value != "" && !should_skip)
+      {
+      const size_t spaces_to_align =
+         (s.size() >= m_value_column) ? 1 : (m_value_column - s.size());
+
+      output << std::string(spaces_to_align, ' ') << value;
+      }
+
+   output << "\n";
+   }
+
+void ASN1_Pretty_Printer::decode(std::ostream& output,
+                                 BER_Decoder& decoder,
+                                 size_t level) const
+   {
+   BER_Object obj = decoder.get_next_object();
+
+   while(obj.type_tag != NO_OBJECT)
+      {
+      const ASN1_Tag type_tag = obj.type_tag;
+      const ASN1_Tag class_tag = obj.class_tag;
+      const size_t length = obj.value.size();
+
+      /* hack to insert the tag+length back in front of the stuff now
+         that we've gotten the type info */
+      DER_Encoder encoder;
+      encoder.add_object(type_tag, class_tag, obj.value);
+      std::vector<uint8_t> bits = encoder.get_contents_unlocked();
+
+      BER_Decoder data(bits);
+
+      if(class_tag & CONSTRUCTED)
+         {
+         BER_Decoder cons_info(obj.value);
+         if(type_tag == SEQUENCE)
+            {
+            emit(output, "SEQUENCE", level, length);
+            decode(output, cons_info, level + 1); // recurse
+            }
+         else if(type_tag == SET)
+            {
+            emit(output, "SET", level, length);
+            decode(output, cons_info, level + 1); // recurse
+            }
+         else
+            {
+            std::string name;
+
+            if((class_tag & APPLICATION) || (class_tag & CONTEXT_SPECIFIC))
+               {
+               name = "cons [" + std::to_string(type_tag) + "]";
+
+               if(class_tag & APPLICATION)
+                  {
+                  name += " appl";
+                  }
+               if(class_tag & CONTEXT_SPECIFIC)
+                  {
+                  name += " context";
+                  }
+               }
+            else
+               {
+               name = asn1_tag_to_string(type_tag) + " (cons)";
+               }
+
+            emit(output, name, level, length);
+            decode(output, cons_info, level + 1); // recurse
+            }
+         }
+      else if((class_tag & APPLICATION) || (class_tag & CONTEXT_SPECIFIC))
+         {
+         if(m_print_context_specific)
+            {
+            std::vector<uint8_t> bits;
+            data.decode(bits, type_tag);
+
+            try
+               {
+               BER_Decoder inner(bits);
+               decode(output, inner, level + 1); // recurse
+               }
+            catch(...)
+               {
+               emit(output, "[" + std::to_string(type_tag) + "]", level, length, format_binary(bits));
+               }
+            }
+         else
+            {
+            emit(output, "[" + std::to_string(type_tag) + "]", level, length, format_binary(bits));
+            }
+         }
+      else if(type_tag == OBJECT_ID)
+         {
+         OID oid;
+         data.decode(oid);
+
+         std::string out = OIDS::lookup(oid);
+         if(out.empty())
+            {
+            out = oid.as_string();
+            }
+         else
+            {
+            out += " [" + oid.as_string() + "]";
+            }
+
+         emit(output, asn1_tag_to_string(type_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;
+
+         /* If it's small, it's probably a number, not a hash */
+         if(number.bits() <= 20)
+            {
+            rep = BigInt::encode(number, BigInt::Decimal);
+            }
+         else
+            {
+            rep = BigInt::encode(number, BigInt::Hexadecimal);
+            }
+
+         std::string str;
+         for(size_t i = 0; i != rep.size(); ++i)
+            {
+            str += static_cast<char>(rep[i]);
+            }
+
+         emit(output, asn1_tag_to_string(type_tag), level, length, str);
+         }
+      else if(type_tag == BOOLEAN)
+         {
+         bool boolean;
+         data.decode(boolean);
+         emit(output, asn1_tag_to_string(type_tag), level, length, (boolean ? "true" : "false"));
+         }
+      else if(type_tag == NULL_TAG)
+         {
+         emit(output, asn1_tag_to_string(type_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);
+
+         try
+            {
+            BER_Decoder inner(decoded_bits);
+            decode(output, inner, level + 1);
+            }
+         catch(...)
+            {
+            emit(output, asn1_tag_to_string(type_tag), level, length, format_binary(decoded_bits));
+            }
+         }
+      else if(ASN1_String::is_string_type(type_tag))
+         {
+         ASN1_String str;
+         data.decode(str);
+         emit(output, asn1_tag_to_string(type_tag), level, length, str.value());
+         }
+      else if(type_tag == UTC_TIME || type_tag == GENERALIZED_TIME)
+         {
+         X509_Time time;
+         data.decode(time);
+         emit(output, asn1_tag_to_string(type_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();
+      }
+   }
+
+}