/* Copyright 2005-2006, Voltage Security, all rights reserved.
 */
#include "vibecrypto.h"
#include "environment.h"
#include "base.h"
#include "libctx.h"
#include "keyobj.h"
#include "dh.h"
#include "mpint.h"
#include "random.h"
#include "errorctx.h"

/* This routine does the work. It allocates and fills in the contexts.
 *
 * @param obj The algorithm object to set.
 * @param primeSizeBits The size of the primeP in bits.
 * @param paramInfo Contains the params from which the keys will be
 * generated.
 * @return an int, 0 if the function completed successfully or a
 * non-zero error code.
 */
static int VOLT_CALLING_CONV SetObjectDHKeyGen VOLT_PROTO_LIST ((
   VoltKeyObject *obj,
   unsigned int primeSizeBits,
   VtDHParamInfo *paramInfo
   ));

int VtKeyPairGenDH (
   VtKeyObject object,
   Pointer info,
   unsigned int flag,
   VtRandomObject random
   )
{
  int status;
  unsigned int msByte, primeSizeBits;
  VoltKeyObject *obj = (VoltKeyObject *)object;
  VtParameterObject pObj = (VtParameterObject)info;
  VtDHParamInfo *paramInfo;
  VOLT_DECLARE_ERROR_TYPE (errorType)
  VOLT_DECLARE_FNCT_LINE (fnctLine)

  do
  {
    /* Check the flag, it should be VOLT_KEY_SET_TYPE_FLAG.
     */
    VOLT_SET_ERROR_TYPE (errorType, VT_ERROR_TYPE_PRIMARY)
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_TYPE;
    if (flag != VOLT_KEY_SET_TYPE_FLAG)
      break;

    /* Check the keyType of the object. It should be 0.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_SET;
    if (obj->keyType != 0)
      break;

    /* The associated info should be a parameter object.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_ASSOCIATED_INFO;
    if (info == (Pointer)0)
      break;

    /* Get the params.
     */
    VOLT_SET_ERROR_TYPE (errorType, 0)
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VtGetParameterParam (
      pObj, VtParameterParamDHParams, (Pointer *)&paramInfo);
    if (status != 0)
    {
      if (status == VT_ERROR_GET_INFO_UNAVAILABLE)
        status = VT_ERROR_INVALID_ASSOCIATED_INFO;
      break;
    }

    /* How big is the prime?
     */
    primeSizeBits = 8;
    msByte = (unsigned int)(paramInfo->primeP.data[0]) & 0xff;
    while ((msByte & 0x80) == 0)
    {
      msByte <<= 1;
      primeSizeBits--;
    }
    primeSizeBits += (paramInfo->primeP.len - 1) * 8;

    VOLT_SET_ERROR_TYPE (errorType, 0)
    VOLT_SET_FNCT_LINE (fnctLine)
    status = SetObjectDHKeyGen (obj, primeSizeBits, paramInfo);

  } while (0);

  /* If everything worked, return 0.
   */
  if (status == 0)
  {
    /* Set the FIPS bit in the object type, this object is a FIPS
     * object.
     */
    obj->voltObject.objectType |= VOLT_OBJECT_TYPE_FIPS;
    return (0);
  }

  /* If something went wrong, indicate that this object is not usable.
   */
  obj->keyType = 0;

  VOLT_LOG_ERROR_INFO (
    0, object, status, 0, errorType,
    (char *)0, "VtKeyPairGenDH", fnctLine, (char *)0)

    return (status);
}

static int SetObjectDHKeyGen (
   VoltKeyObject *obj,
   unsigned int primeSizeBits,
   VtDHParamInfo *paramInfo
   )
{
  int status;
  unsigned int bufferSize, pLen, qLen, gLen;
  unsigned char *buffer = (unsigned char *)0;
  VoltLibCtx *libCtx = (VoltLibCtx *)(obj->voltObject.libraryCtx);
  VoltDHKeyGenCtx *dhGenCtx;
  VOLT_DECLARE_FNCT_LINE (fnctLine)

  do
  {
    /* Get the lengths from the params.
     */
    pLen = paramInfo->primeP.len;
    qLen = paramInfo->subprimeQ.len;
    gLen = paramInfo->baseG.len;

#if VOLT_BUILD == VOLT_BUILD_FIPS_SHARED
    /* If this is the FIPS build, there must be a subprimeQ.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_ASSOCIATED_INFO;
    if (qLen == 0)
      break;
#endif

    /* Allocate enough space for a DHKeyGenCtx. The buffers after the
     * struct will be byte arrays, so no need to worry about alignment.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_MEMORY;
    bufferSize = sizeof (VoltDHKeyGenCtx) + pLen + qLen + gLen;
    buffer = (unsigned char *)Z2Malloc (bufferSize, VOLT_MEMORY_SENSITIVE);
    if (buffer == (unsigned char *)0)
      break;
    Z2Memset (buffer, 0, bufferSize);

    /* Locate the context.
     */
    dhGenCtx = (VoltDHKeyGenCtx *)buffer;

    /* Populate the context.
     */
    dhGenCtx->mpCtx = (VtMpIntCtx)(obj->mpCtx);
    dhGenCtx->primeSizeBits = primeSizeBits;
    dhGenCtx->primeP.data = buffer + sizeof (VoltDHKeyGenCtx);
    if (qLen != 0)
      dhGenCtx->subprimeQ.data = dhGenCtx->primeP.data + pLen;
    dhGenCtx->baseG.data = dhGenCtx->primeP.data + pLen + qLen;

    /* Copy the params.
     */
    Z2Memcpy (dhGenCtx->primeP.data, paramInfo->primeP.data, pLen);
    dhGenCtx->primeP.len = pLen;
    if (qLen != 0)
    {
      Z2Memcpy (dhGenCtx->subprimeQ.data, paramInfo->subprimeQ.data, qLen);
      dhGenCtx->subprimeQ.len = qLen;
    }
    Z2Memcpy (dhGenCtx->baseG.data, paramInfo->baseG.data, gLen);
    dhGenCtx->baseG.len = gLen;

    obj->keyType = VOLT_KEY_ALG_DH | VOLT_KEY_TYPE_GEN_PAIR;
    obj->GenerateKey = DHGenerateKeyPair;
    obj->localGenerateCtx = (Pointer)dhGenCtx;
    obj->LocalGenerateCtxDestroy = VoltSimpleCtxDestroy;

    status = 0;

  } while (0);

  /* If everything worked, return 0.
   */
  if (status == 0)
    return (0);

  /* If something went wrong, destroy anything we created and indicate
   * that this object is not usable.
   */
  if (buffer != (unsigned char *)0)
    Z2Free (buffer);

  obj->keyType = 0;

  VOLT_LOG_ERROR_INFO (
    0, obj, status, 0, VT_ERROR_TYPE_PRIMARY,
    (char *)0, "SetObjectDHKeyGen", fnctLine, (char *)0)

  return (status);
}