Problem with gcry_sexp_build

[cplusplushelp@gmx.net]

hi,
I'm using the following functions to encrypt a session key but I recive a
segmantation fault!

typedef struct
{
  MPI *prikey; /*private key*/
  MPI *pubkey; /*public key*/
} pkkey;

int wcrypt_rsagenkey(pkkey *key,int bits)
{
  int ret;
  GCRY_SEXP parms;
  GCRY_SEXP key_;
  gcry_sexp_build(&parms, NULL, "(genkey(rsa(nbits %d)))", bits); /*build
key*/
  ret=gcry_pk_genkey(&key_,parms);
  if( (key->pubkey=malloc(sizeof(MPI))) ==NULL ||
(key->prikey=malloc(sizeof(MPI))) ) /*?? is here the problem?*/
    return -1;
  /*extract public and private key from GCRY_SEXP structure*/
  wcrypt_key_from_sexp(key->pubkey,key_,"public-key","ne"); /*the
key_from_sexp function from gnupg*/
  wcrypt_key_from_sexp(key->prikey,key_,"private-key","ne");
  gcry_sexp_release(parms);
  gcry_sexp_dump(key_);
  gcry_sexp_release(key_);
  return ret;
}

int wcrypt_pkencrypt(enum pkalgo alg,unsigned char*sdata,size_t
ndata,unsigned char*to,size_t nto,pkkey key)
{
  GCRY_SEXP list,s_pkey,s_data,s_ciph;
  GCRY_MPI* pkey=key.pubkey;
  GCRY_MPI data,resarr[2];

  gcry_mpi_scan(&data,GCRYMPI_FMT_USG,sdata,&ndata);
  switch(alg)
  {
  case GCRY_PK_ELG:
  case GCRY_PK_ELG_E:
    if(gcry_sexp_build ( &s_pkey, NULL,
			 "(public-key(elg(p%m)(g%m)(y%m)))",
			 pkey[0], pkey[1], pkey[2] ))
      return 1;
    break;
  case GCRY_PK_RSA:
    if(gcry_sexp_build( &s_pkey, NULL, 
                        "(public-key(rsa(n%m)(e%m)))",
			pkey[0] /* n */, pkey[1] /* e */ )) /*here the SEGFAULT happens!*/
      return 1;
    break;
  default:
    return 1;
  }
  /* put the data into a simple list */
  if ( gcry_sexp_build( &s_data, NULL, "%m", data ) )
    return 1;
  
  /* pass it to libgcrypt */
  gcry_pk_encrypt( &s_ciph, s_data, s_pkey );
  gcry_sexp_release( s_data );
  gcry_sexp_release( s_pkey );
  
  /* extract the MPI values */        
  list = gcry_sexp_find_token( s_ciph, "a" , 0 );
  if(!list)
    return 1;
  resarr[0] = gcry_sexp_nth_mpi( list, 1, 0 );
  if(!resarr[0])
    return 1;
  gcry_sexp_release ( list );
  
  list = gcry_sexp_find_token( s_ciph, "b" , 0 );
  if(!list)
    return 1;
  resarr[1] = gcry_sexp_nth_mpi( list, 1, 0 );
  if(!resarr[1])
    return 1;
  gcry_sexp_release ( list );
  gcry_mpi_print(GCRYMPI_FMT_USG,to,&nto,resarr[0]);
  return 0;
}

What is wrong with this code?

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