PEM codec module

1 files changed, 141 insertions, 0 deletions

diff --git a/src/codec/pem/pem.cpp b/src/codec/pem/pem.cpp
new file mode 100644
index 000000000..fb0be6fd5
--- /dev/null
+++ b/src/codec/pem/pem.cpp
@@ -0,0 +1,141 @@
+/*************************************************
+* PEM Encoding/Decoding Source File              *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/pem.h>
+#include <botan/filters.h>
+#include <botan/parsing.h>
+
+namespace Botan {
+
+namespace PEM_Code {
+
+/*************************************************
+* PEM encode BER/DER-encoded objects             *
+*************************************************/
+std::string encode(const byte der[], u32bit length, const std::string& label,
+                   u32bit width)
+   {
+   const std::string PEM_HEADER = "-----BEGIN " + label + "-----\n";
+   const std::string PEM_TRAILER = "-----END " + label + "-----\n";
+
+   Pipe pipe(new Base64_Encoder(true, width));
+   pipe.process_msg(der, length);
+   return (PEM_HEADER + pipe.read_all_as_string() + PEM_TRAILER);
+   }
+
+/*************************************************
+* PEM encode BER/DER-encoded objects             *
+*************************************************/
+std::string encode(const MemoryRegion<byte>& data, const std::string& label,
+                   u32bit width)
+   {
+   return encode(data, data.size(), label, width);
+   }
+
+/*************************************************
+* Decode PEM down to raw BER/DER                 *
+*************************************************/
+SecureVector<byte> decode_check_label(DataSource& source,
+                                      const std::string& label_want)
+   {
+   std::string label_got;
+   SecureVector<byte> ber = decode(source, label_got);
+   if(label_got != label_want)
+      throw Decoding_Error("PEM: Label mismatch, wanted " + label_want +
+                           ", got " + label_got);
+   return ber;
+   }
+
+/*************************************************
+* Decode PEM down to raw BER/DER                 *
+*************************************************/
+SecureVector<byte> decode(DataSource& source, std::string& label)
+   {
+   const u32bit RANDOM_CHAR_LIMIT = 8;
+
+   const std::string PEM_HEADER1 = "-----BEGIN ";
+   const std::string PEM_HEADER2 = "-----";
+   u32bit position = 0;
+
+   while(position != PEM_HEADER1.length())
+      {
+      byte b;
+      if(!source.read_byte(b))
+         throw Decoding_Error("PEM: No PEM header found");
+      if(b == PEM_HEADER1[position])
+         ++position;
+      else if(position >= RANDOM_CHAR_LIMIT)
+         throw Decoding_Error("PEM: Malformed PEM header");
+      else
+         position = 0;
+      }
+   position = 0;
+   while(position != PEM_HEADER2.length())
+      {
+      byte b;
+      if(!source.read_byte(b))
+         throw Decoding_Error("PEM: No PEM header found");
+      if(b == PEM_HEADER2[position])
+         ++position;
+      else if(position)
+         throw Decoding_Error("PEM: Malformed PEM header");
+
+      if(position == 0)
+         label += static_cast<char>(b);
+      }
+
+   Pipe base64(new Base64_Decoder);
+   base64.start_msg();
+
+   const std::string PEM_TRAILER = "-----END " + label + "-----";
+   position = 0;
+   while(position != PEM_TRAILER.length())
+      {
+      byte b;
+      if(!source.read_byte(b))
+         throw Decoding_Error("PEM: No PEM trailer found");
+      if(b == PEM_TRAILER[position])
+         ++position;
+      else if(position)
+         throw Decoding_Error("PEM: Malformed PEM trailer");
+
+      if(position == 0)
+         base64.write(b);
+      }
+   base64.end_msg();
+   return base64.read_all();
+   }
+
+/*************************************************
+* Search for a PEM signature                     *
+*************************************************/
+bool matches(DataSource& source, const std::string& extra,
+             u32bit search_range)
+   {
+   const std::string PEM_HEADER = "-----BEGIN " + extra;
+
+   SecureVector<byte> search_buf(search_range);
+   u32bit got = source.peek(search_buf, search_buf.size(), 0);
+
+   if(got < PEM_HEADER.length())
+      return false;
+
+   u32bit index = 0;
+
+   for(u32bit j = 0; j != got; ++j)
+      {
+      if(search_buf[j] == PEM_HEADER[index])
+         ++index;
+      else
+         index = 0;
+      if(index == PEM_HEADER.size())
+         return true;
+      }
+   return false;
+   }
+
+}
+
+}