/* Copyright 2003-2006, Voltage Security, all rights reserved.
 */
#include "vibecrypto.h"
#include "environment.h"
#include "base.h"
#include "libctx.h"
#include "keyobj.h"
#include "dsa.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 SetObjectDSAKeyGen VOLT_PROTO_LIST ((
   VoltKeyObject *obj,
   unsigned int primeSizeBits,
   VtDSAParamInfo *paramInfo
));

int VtKeyPairGenDSAAndParams (
   VtKeyObject object,
   Pointer info,
   unsigned int flag,
   VtRandomObject random
   )
{
  int status;
  unsigned int primeSizeBits;
  VoltKeyObject *obj = (VoltKeyObject *)object;
  VoltLibCtx *libCtx = (VoltLibCtx *)(obj->voltObject.libraryCtx);
  VtDSAParamInfo paramInfo;
  VOLT_DECLARE_ERROR_TYPE (errorType)
  VOLT_DECLARE_FNCT_LINE (fnctLine)

  Z2Memset (&paramInfo, 0, sizeof (paramInfo));

  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 pointer to an unsigned int.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_ASSOCIATED_INFO;
    if (info == (Pointer)0)
      break;

    primeSizeBits = *((unsigned int *)info);

    /* For now we support only 1024 bits.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    if (primeSizeBits != 1024)
      break;

    /* If using this KeyGenImpl, the key must already have an mpCtx
     * loaded.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_KEY_OBJ;
    if (obj->mpCtx == (VoltMpIntCtx *)0)
      break;

    VOLT_SET_ERROR_TYPE (errorType, 0)
    VOLT_SET_FNCT_LINE (fnctLine)
    status = SetObjectDSAKeyGen (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 (
    (VtLibCtx)libCtx, status, errorType, fnctLine,
    "VtKeyPairGenDSAAndParams", (char *)0)

  return (status);
}

int VtKeyPairGenDSA (
   VtKeyObject object,
   Pointer info,
   unsigned int flag,
   VtRandomObject random
   )
{
  int status;
  unsigned int msByte, primeSizeBits;
  VoltKeyObject *obj = (VoltKeyObject *)object;
  VtParameterObject pObj = (VtParameterObject)info;
  VtDSAParamInfo *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, VtParameterParamDSAParams, (Pointer *)&paramInfo);
    if (status != 0)
    {
      if (status == VT_ERROR_GET_INFO_UNAVAILABLE)
        status = VT_ERROR_INVALID_ASSOCIATED_INFO;
      break;
    }

    /* How big is the subprime?
     */
    primeSizeBits = 8;
    msByte = (unsigned int)(paramInfo->subprimeQ.data[0]) & 0xff;
    while ((msByte & 0x80) == 0)
    {
      msByte <<= 1;
      primeSizeBits--;
    }
    primeSizeBits += (paramInfo->subprimeQ.len - 1) * 8;
    if (primeSizeBits != 160)
      break;

    /* How big is the prime?
     */
    VOLT_SET_ERROR_TYPE (errorType, VT_ERROR_TYPE_PRIMARY)
    VOLT_SET_FNCT_LINE (fnctLine)
    status = VT_ERROR_INVALID_ASSOCIATED_INFO;
    primeSizeBits = 8;
    msByte = (unsigned int)(paramInfo->primeP.data[0]) & 0xff;
    while ((msByte & 0x80) == 0)
    {
      msByte <<= 1;
      primeSizeBits--;
    }
    primeSizeBits += (paramInfo->primeP.len - 1) * 8;
    if (primeSizeBits != 1024)
      break;

    VOLT_SET_ERROR_TYPE (errorType, 0)
    VOLT_SET_FNCT_LINE (fnctLine)
    status = SetObjectDSAKeyGen (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 (
    obj->voltObject.libraryCtx, status, errorType, fnctLine,
    "VtKeyPairGenDSA", (char *)0)

  return (status);
}

static int SetObjectDSAKeyGen (
   VoltKeyObject *obj,
   unsigned int primeSizeBits,
   VtDSAParamInfo *paramInfo
   )
{
  int status;
  unsigned int bufferSize, primePLen, subprimeQLen, baseGLen;
  unsigned char *buffer = (unsigned char *)0;
  VoltLibCtx *libCtx = (VoltLibCtx *)(obj->voltObject.libraryCtx);
  VoltDsaKeyGenCtx *dsaGenCtx;
  VOLT_DECLARE_FNCT_LINE (fnctLine)

  do
  {
    /* If we have params, get the lengths from them. If not, use
     * defaults.
     */
    if (paramInfo->primeP.data != (unsigned char *)0)
    {
      primePLen = paramInfo->primeP.len;
      subprimeQLen = paramInfo->subprimeQ.len;
      baseGLen = paramInfo->baseG.len;
    }
    else
    {
      primePLen = (primeSizeBits + 7) / 8;
      subprimeQLen = 20;
      baseGLen = primePLen;
    }

    /* Allocate enough space for a DsaKeyGenCtx. 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 (VoltDsaKeyGenCtx) + primePLen + subprimeQLen + baseGLen;
    buffer = (unsigned char *)Z2Malloc (bufferSize, VOLT_MEMORY_SENSITIVE);
    if (buffer == (unsigned char *)0)
      break;
    Z2Memset (buffer, 0, bufferSize);

    /* Locate the context.
     */
    dsaGenCtx = (VoltDsaKeyGenCtx *)buffer;

    /* Populate the context.
     */
    dsaGenCtx->mpCtx = (VtMpIntCtx)(obj->mpCtx);
    dsaGenCtx->primeSizeBits = primeSizeBits;
    dsaGenCtx->primeP.data = buffer + sizeof (VoltDsaKeyGenCtx);
    dsaGenCtx->subprimeQ.data = dsaGenCtx->primeP.data + primePLen;
    dsaGenCtx->baseG.data = dsaGenCtx->subprimeQ.data + subprimeQLen;

    /* Copy the params, if we have them.
     */
    if (paramInfo->primeP.data != (unsigned char *)0)
    {
      Z2Memcpy (dsaGenCtx->primeP.data, paramInfo->primeP.data, primePLen);
      dsaGenCtx->primeP.len = primePLen;
      Z2Memcpy (
        dsaGenCtx->subprimeQ.data, paramInfo->subprimeQ.data, subprimeQLen);
      dsaGenCtx->subprimeQ.len = subprimeQLen;
      Z2Memcpy (dsaGenCtx->baseG.data, paramInfo->baseG.data, baseGLen);
      dsaGenCtx->baseG.len = baseGLen;
    }

    obj->keyType = VOLT_KEY_ALG_DSA | VOLT_KEY_TYPE_GEN_PAIR;
    obj->GenerateKey = DSAGenerateKeyPair;
    obj->localGenerateCtx = (Pointer)dsaGenCtx;
    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 (
    (VtLibCtx)libCtx, status, VT_ERROR_TYPE_PRIMARY, fnctLine,
    "SetObjectDSAKeyGen", (char *)0)

  return (status);
}