From b8766a2041d57a3aa49c3855902953f8de0b0ec1 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@anytun.org>
Date: Sat, 23 Feb 2008 23:05:43 +0000
Subject: - keyderivation and cipher should work now   however it needs further
 testing

- rewrite of Buffer and Packets
---
 mpi.cpp | 80 ++++++++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 59 insertions(+), 21 deletions(-)

(limited to 'mpi.cpp')

diff --git a/mpi.cpp b/mpi.cpp
index 18a3349..a2590fa 100644
--- a/mpi.cpp
+++ b/mpi.cpp
@@ -36,41 +36,71 @@
 #include <stdexcept>
 #include <gcrypt.h>
 
+#include <iostream>
 
-Mpi::Mpi()
+Mpi::Mpi() : val_(NULL)
 {
-  val_ = gcry_mpi_new(1);
+  val_ = gcry_mpi_set_ui(NULL, 0);
+  if(!val_)
+    throw std::bad_alloc();
 }
 
-Mpi::Mpi(u_int8_t length)
+Mpi::Mpi(u_int8_t length) : val_(NULL)
 {
   val_ = gcry_mpi_new(length);
+  if(!val_)
+    throw std::bad_alloc();
 }
 
-Mpi::Mpi(const Mpi &src)
+Mpi::Mpi(const Mpi &src) : val_(NULL)
 {
   val_ = gcry_mpi_copy(src.val_);
+  if(!val_)
+    throw std::bad_alloc();
 }
 
-Mpi::Mpi(const u_int8_t * src, u_int32_t len)
+Mpi::Mpi(const u_int8_t* src, u_int32_t len) : val_(NULL)
 {
-  gcry_mpi_scan( &val_, GCRYMPI_FMT_STD, src, len, NULL );
+  u_int8_t* src_cpy = new u_int8_t[len+1];
+  if(!src_cpy)
+    throw std::bad_alloc();
+
+  u_int8_t* buf = src_cpy;
+  u_int32_t buf_len = len;
+  if(src[0] & 0x80) // this would be a negative number, scan can't handle this :(
+  {
+    src_cpy[0] = 0;
+    buf++;
+    buf_len++;
+  }
+  std::memcpy(buf, src, len);
+
+  gcry_mpi_scan( &val_, GCRYMPI_FMT_STD, src_cpy, buf_len, NULL );
+  delete[] src_cpy;
+  if(!val_)
+    throw std::bad_alloc();
 }
 
 Mpi::~Mpi()
 {
-  gcry_mpi_release( val_ );
+  gcry_mpi_release( val_ ); 
 }
 
 
 void Mpi::operator=(const Mpi &src)
 {
+  gcry_mpi_release( val_ ); 
   val_ = gcry_mpi_copy(src.val_);
+  if(!val_)
+    throw std::bad_alloc();
 }
 
 void Mpi::operator=(const u_int32_t src)
 {
-  gcry_mpi_set_ui(val_, src);
+  gcry_mpi_release( val_ ); 
+  val_ = gcry_mpi_set_ui(NULL, src);
+  if(!val_)
+    throw std::bad_alloc();
 }
 
 Mpi Mpi::operator+(const Mpi &b) const
@@ -125,22 +155,29 @@ Mpi Mpi::mul2exp(u_int32_t e) const
   return res;
 }
 
-u_int8_t* Mpi::getNewBuf(u_int32_t buf_len) const
+//TODO: problem, seems as gcry_mpi_(a)print doesn't work for mpi values of '0'
+u_int8_t* Mpi::getNewBuf(u_int32_t* written) const
 {
-  // u_int32_t len = 0;
-  u_int32_t written = 0;
+  u_int8_t* res_cpy;
+  gcry_mpi_aprint( GCRYMPI_FMT_STD, &res_cpy, written, val_ );
+  if(!res_cpy)
+    throw std::bad_alloc();
+    
+  u_int8_t* buf = res_cpy;
+  if(*written > 1 && ! (res_cpy[0])) // positive number with highestBit set
+  {
+    buf++;
+    (*written)--;
+  }
+
+  u_int8_t* res = new u_int8_t[*written];
+  if(!res)
+    throw std::bad_alloc();
 
-  u_int8_t *res = NULL;
-  res = new u_int8_t[buf_len];
-  std::memset(res, 0, buf_len);
+  std::memcpy(res, buf, *written);
 
-  //  len = gcry_mpi_get_nbits( val_ );
-  //  if( len%8 == 0 )
-  //    len = len/8;
-  //  else
-  //    len = (len/8)+1;
+  gcry_free(res_cpy);
 
-  gcry_mpi_print( GCRYMPI_FMT_STD, res, buf_len, &written, val_ );
   return res;
 }
 
@@ -151,7 +188,8 @@ std::string Mpi::getHexDump() const
 //   u_int32_t len;
 //   gcry_mpi_aprint( GCRYMPI_FMT_HEX, &buf, &len, val_ );
 //   std::string res(buf, len);
-  
+//   delete[] buf;
+
   gcry_mpi_dump( val_ );
   std::string res("\n");
   return res;
-- 
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