/* Copyright 2003-2006, Voltage Security, all rights reserved.
 */

#include "vibe.h"
#include "environment.h"
#include "base.h"
#include "libctx.h"
#include "pubkeyder.h"
#include "derhelp.h"
#include "errorctx.h"

/* Set up the OpenSSL ASN.1 template.
 */
ASN1_SEQUENCE (Asn1SubjectPublicKey) =
{
  ASN1_SIMPLE (Asn1SubjectPublicKey, algId, Asn1AlgorithmId),
  ASN1_SIMPLE (Asn1SubjectPublicKey, encodedKey, ASN1_BIT_STRING)
} ASN1_SEQUENCE_END (Asn1SubjectPublicKey);

IMPLEMENT_ASN1_FUNCTIONS (Asn1SubjectPublicKey)

int VoltEncodeSubjectPublicKeyDer (
   VoltLibCtx *libCtx,
   unsigned char *oid,
   unsigned int oidLen,
   unsigned char *params,
   unsigned int paramsLen,
   unsigned char *encodedKey,
   unsigned int encodedKeyLen,
   unsigned char *keyDer,
   unsigned int bufferSize,
   unsigned int *keyDerLen
   )
{
  int status;
  unsigned char *temp;
  Asn1SubjectPublicKey *subjPubKey = (Asn1SubjectPublicKey *)0;
  VOLT_DECLARE_FNCT_LINE (fnctLine)

  do
  {
    /* Create the ASN.1 "object".
     */
    status = VT_ERROR_MEMORY;
    VOLT_SET_FNCT_LINE (fnctLine)
    subjPubKey = Asn1SubjectPublicKey_new ();
    if (subjPubKey == (Asn1SubjectPublicKey *)0)
      break;

    /* Set the fields.
     */
    VOLT_SET_FNCT_LINE (fnctLine)
    if (Asn1ObjectId_set (subjPubKey->algId->oid, oid, oidLen) != 1)
      break;
    VOLT_SET_FNCT_LINE (fnctLine)
    if (Asn1Encoded_setCreate (
      &(subjPubKey->algId->params), params, paramsLen) != 1)
      break;
    VOLT_SET_FNCT_LINE (fnctLine)
    if (ASN1_STRING_set (
      subjPubKey->encodedKey, encodedKey, encodedKeyLen) != 1)
      break;

    /* The standards specify that the unused bits will be 0, regardless
     * of the values of the trailing bits (this is common in unnamed
     * bit strings). However, how does OpenSSL's ASN.1 engine override
     * the default behavior of counting the trailing 0 bits? Because
     * there is almost no documentation to accompany OpenSSL (who could
     * possibly believe that no documentation is remotely acceptable in
     * software!?) and the source code is practically uncommented and
     * written to be the hands-down winner of the Obfuscated C Code
     * Competition, there appears to be no "official" way to solve this
     * problem.
     * The solution appears to be to set the flags field in the
     * ASN1_BIT_STRING struct to ASN1_STRING_FLAG_BITS_LEFT.
     * So far, we've tested and it works.
     */
    subjPubKey->encodedKey->flags = ASN1_STRING_FLAG_BITS_LEFT;

    /* How big does the buffer need to be?
     */
    status = VT_ERROR_INVALID_INPUT;
    VOLT_SET_FNCT_LINE (fnctLine)
    *keyDerLen = i2d_Asn1SubjectPublicKey (subjPubKey, (unsigned char **)0);
    if (*keyDerLen == 0)
      break;

    status = VT_ERROR_BUFFER_TOO_SMALL;
    VOLT_SET_FNCT_LINE (fnctLine)
    if (bufferSize < *keyDerLen)
      break;

    /* Now encode into the buffer.
     */
    status = VT_ERROR_INVALID_INPUT;
    temp = keyDer;
    VOLT_SET_FNCT_LINE (fnctLine)
    *keyDerLen = i2d_Asn1SubjectPublicKey (subjPubKey, &temp);
    if (*keyDerLen == 0)
      break;

    status = 0;
  } while (0);

  if (subjPubKey != (Asn1SubjectPublicKey *)0)
    Asn1SubjectPublicKey_free (subjPubKey);

  VOLT_LOG_ERROR_COMPARE (
    status, (VtLibCtx)libCtx, status, VT_ERROR_TYPE_PRIMARY,
    fnctLine, "VoltEncodeSubjectPublicKeyDer", (char *)0)

  return (status);
}

int VoltDecodeSubjPubKeyCreate (
   VoltLibCtx *libCtx,
   unsigned char *encoding,
   unsigned int maxEncodingLen,
   Asn1SubjectPublicKey **subjPubKey
   )
{
  int status;
  Asn1SubjectPublicKey *newSubjPubKey = (Asn1SubjectPublicKey *)0;
  unsigned char *temp;
  VOLT_DECLARE_FNCT_LINE (fnctLine)

  do
  {
    /* Create the "object".
     */
    status = VT_ERROR_MEMORY;
    VOLT_SET_FNCT_LINE (fnctLine)
    newSubjPubKey = Asn1SubjectPublicKey_new ();
    if (newSubjPubKey == (Asn1SubjectPublicKey *)0)
      break;

    /* Decode.
     */
    status = VT_ERROR_UNKNOWN_BER;
    temp = encoding;
    VOLT_SET_FNCT_LINE (fnctLine)
    d2i_Asn1SubjectPublicKey (&newSubjPubKey, &temp, maxEncodingLen);

    /* Did it work?
     */
    if (newSubjPubKey == (Asn1SubjectPublicKey *)0)
      break;

    /* If successful, return the object.
     */
    *subjPubKey = newSubjPubKey;
    status = 0;
  } while (0);

  if (status == 0)
    return (0);

  /* If there was an error, destroy anything we created.
   */
  if (newSubjPubKey != (Asn1SubjectPublicKey *)0)
    Asn1SubjectPublicKey_free (newSubjPubKey);

  VOLT_LOG_ERROR_COMPARE (
    status, (VtLibCtx)libCtx, status, VT_ERROR_TYPE_PRIMARY,
    fnctLine, "VoltDecodeSubjPubKeyCreate", (char *)0)

  return (status);
}