/*
 * $Id$
 * 'OpenSSL for Ruby' project
 * Copyright (C) 2001-2002  Michal Rokos <m.rokos@sh.cvut.cz>
 * All rights reserved.
 */
/*
 * This program is licenced under the same licence as Ruby.
 * (See the file 'LICENCE'.)
 */
#if !defined(OPENSSL_NO_RSA)

#include "ossl.h"

#define GetPKeyRSA(obj, pkey) do { \
    GetPKey(obj, pkey); \
    if (EVP_PKEY_type(pkey->type) != EVP_PKEY_RSA) { /* PARANOIA? */ \
	ossl_raise(rb_eRuntimeError, "THIS IS NOT A RSA!") ; \
    } \
} while (0)

#define RSA_PRIVATE(rsa) ((rsa)->p && (rsa)->q)

/*
 * Classes
 */
VALUE cRSA;
VALUE eRSAError;

/*
 * Public
 */
static VALUE
rsa_instance(VALUE klass, RSA *rsa)
{
    EVP_PKEY *pkey;
    VALUE obj;
	
    if (!rsa) {
	return Qfalse;
    }
    if (!(pkey = EVP_PKEY_new())) {
	return Qfalse;
    }
    if (!EVP_PKEY_assign_RSA(pkey, rsa)) {
	EVP_PKEY_free(pkey);
	return Qfalse;
    }
    WrapPKey(klass, obj, pkey);
	
    return obj;
}

VALUE
ossl_rsa_new(EVP_PKEY *pkey)
{
    VALUE obj;

    if (!pkey) {
	obj = rsa_instance(cRSA, RSA_new());
    }
    else {
	if (EVP_PKEY_type(pkey->type) != EVP_PKEY_RSA) {
	    ossl_raise(rb_eTypeError, "Not a RSA key!");
	}
	WrapPKey(cRSA, obj, pkey);
    }
    if (obj == Qfalse) {
	ossl_raise(eRSAError, NULL);
    }

    return obj;
}

/*
 * Private
 */
/*
 * CB for yielding when generating RSA data
 */
static void
ossl_rsa_generate_cb(int p, int n, void *arg)
{
    VALUE ary;

    ary = rb_ary_new2(2);
    rb_ary_store(ary, 0, INT2NUM(p));
    rb_ary_store(ary, 1, INT2NUM(n));

    rb_yield(ary);
}

static RSA *
rsa_generate(int size, int exp)
{
    void (*cb)(int, int, void *) = NULL;
	
    if (rb_block_given_p()) {
	cb = ossl_rsa_generate_cb;
    }
    return RSA_generate_key(size, exp, cb, NULL);
}

static VALUE
ossl_rsa_s_generate(int argc, VALUE *argv, VALUE klass)
{
    RSA *rsa;
    VALUE size, exp;
    VALUE obj;

    rb_scan_args(argc, argv, "11", &size, &exp);

    rsa = rsa_generate(NUM2INT(size), NIL_P(exp) ? RSA_F4 : NUM2INT(exp)); /* err handled by rsa_instance */
    obj = rsa_instance(klass, rsa);

    if (obj == Qfalse) {
	RSA_free(rsa);
	ossl_raise(eRSAError, NULL);
    }

    return obj;
}

static VALUE
ossl_rsa_initialize(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    RSA *rsa;
    BIO *in;
    char *passwd = NULL;
    VALUE buffer, pass;
	
    GetPKey(self, pkey);
	
    rb_scan_args(argc, argv, "11", &buffer, &pass);

    if (FIXNUM_P(buffer)) {
	rsa = rsa_generate(FIX2INT(buffer), NIL_P(pass) ? RSA_F4 : NUM2INT(pass));
	if (!rsa) {
	    ossl_raise(eRSAError, NULL);
	}
    }
    else {
	StringValue(buffer);
	if (!NIL_P(pass)) {
	    passwd = StringValuePtr(pass);
	}
	if (!(in = BIO_new_mem_buf(RSTRING(buffer)->ptr, RSTRING(buffer)->len))){
	    ossl_raise(eRSAError, NULL);
	}

	rsa = PEM_read_bio_RSAPrivateKey(in, NULL, ossl_pem_passwd_cb, passwd);
	if (!rsa) {
	    BIO_reset(in);

	    rsa = PEM_read_bio_RSAPublicKey(in, NULL, NULL, NULL);
	}
	if (!rsa) {
	    BIO_reset(in);

	    rsa = PEM_read_bio_RSA_PUBKEY(in, NULL, NULL, NULL);
	}
	BIO_free(in);

	if (!rsa) {
	    ossl_raise(eRSAError, "Neither PUB key nor PRIV key:");
	}
    }
    if (!EVP_PKEY_assign_RSA(pkey, rsa)) {
	RSA_free(rsa);
	ossl_raise(eRSAError, NULL);
    }

    return self;
}

static VALUE
ossl_rsa_is_public(VALUE self)
{
    EVP_PKEY *pkey;

    GetPKeyRSA(self, pkey);
    /*
     * SURPRISE! :-))
     * Every key is public at the same time!
     */
    return Qtrue;
}

static VALUE
ossl_rsa_is_private(VALUE self)
{
    EVP_PKEY *pkey;
	
    GetPKeyRSA(self, pkey);
	
    return (RSA_PRIVATE(pkey->pkey.rsa)) ? Qtrue : Qfalse;
}

static VALUE
ossl_rsa_export(int argc, VALUE *argv, VALUE self)
{
    EVP_PKEY *pkey;
    BIO *out;
    BUF_MEM *buf;
    const EVP_CIPHER *ciph = NULL;
    char *passwd = NULL;
    VALUE cipher, pass, str;

    GetPKeyRSA(self, pkey);

    rb_scan_args(argc, argv, "02", &cipher, &pass);

    if (!NIL_P(cipher)) {
	ciph = GetCipherPtr(cipher);
	if (!NIL_P(pass)) {
	    passwd = StringValuePtr(pass);
	}
    }
    if (!(out = BIO_new(BIO_s_mem()))) {
	ossl_raise(eRSAError, NULL);
    }
    if (RSA_PRIVATE(pkey->pkey.rsa)) {
	if (!PEM_write_bio_RSAPrivateKey(out, pkey->pkey.rsa, ciph,
					 NULL, 0, ossl_pem_passwd_cb, passwd)) {
	    BIO_free(out);
	    ossl_raise(eRSAError, NULL);
	}
    } else {
	if (!PEM_write_bio_RSAPublicKey(out, pkey->pkey.rsa)) {
	    BIO_free(out);
	    ossl_raise(eRSAError, NULL);
	}
    }
    BIO_get_mem_ptr(out, &buf);
    str = rb_str_new(buf->data, buf->length);
    BIO_free(out);
    
    return str;
}

static VALUE
ossl_rsa_public_encrypt(VALUE self, VALUE buffer)
{
    EVP_PKEY *pkey;
    char *buf;
    int buf_len;
    VALUE str;
	
    GetPKeyRSA(self, pkey);

    StringValue(buffer);
	
    if (!(buf = OPENSSL_malloc(RSA_size(pkey->pkey.rsa) + 16))) {
	ossl_raise(eRSAError, NULL);
    }
    buf_len = RSA_public_encrypt(RSTRING(buffer)->len, RSTRING(buffer)->ptr,
				 buf, pkey->pkey.rsa, RSA_PKCS1_PADDING);
    if (buf_len < 0){
	OPENSSL_free(buf);
	ossl_raise(eRSAError, NULL);
    }
    str = rb_str_new(buf, buf_len);
    OPENSSL_free(buf);

    return str;
}

static VALUE
ossl_rsa_public_decrypt(VALUE self, VALUE buffer)
{
    EVP_PKEY *pkey;
    char *buf;
    int buf_len;
    VALUE str;

    GetPKeyRSA(self, pkey);
    StringValue(buffer);
    if (!(buf = OPENSSL_malloc(RSA_size(pkey->pkey.rsa) + 16))) {
	ossl_raise(eRSAError, NULL);
    }
    buf_len = RSA_public_decrypt(RSTRING(buffer)->len, RSTRING(buffer)->ptr,
				 buf, pkey->pkey.rsa, RSA_PKCS1_PADDING);
    if(buf_len < 0) {
	OPENSSL_free(buf);
	ossl_raise(eRSAError, NULL);
    }
    str = rb_str_new(buf, buf_len);
    OPENSSL_free(buf);
    
    return str;
}

static VALUE
ossl_rsa_private_encrypt(VALUE self, VALUE buffer)
{
    EVP_PKEY *pkey;
    char *buf;
    int buf_len;
    VALUE str;
	
    GetPKeyRSA(self, pkey);
    if (!RSA_PRIVATE(pkey->pkey.rsa)) {
	ossl_raise(eRSAError, "PRIVATE key needed for this operation!");
    }	
    StringValue(buffer);
    if (!(buf = OPENSSL_malloc(RSA_size(pkey->pkey.rsa) + 16))) {
	ossl_raise(eRSAError, "Memory alloc error");
    }
    buf_len = RSA_private_encrypt(RSTRING(buffer)->len, RSTRING(buffer)->ptr,
				  buf, pkey->pkey.rsa, RSA_PKCS1_PADDING);
    if (buf_len < 0){
	OPENSSL_free(buf);
	ossl_raise(eRSAError, NULL);
    }
    str = rb_str_new(buf, buf_len);
    OPENSSL_free(buf);
    
    return str;
}

static VALUE
ossl_rsa_private_decrypt(VALUE self, VALUE buffer)
{
    EVP_PKEY *pkey;
    char *buf;
    int buf_len;
    VALUE str;

    GetPKeyRSA(self, pkey);
    if (!RSA_PRIVATE(pkey->pkey.rsa)) {
	ossl_raise(eRSAError, "Private RSA key needed!");
    }
    StringValue(buffer);
    if (!(buf = OPENSSL_malloc(RSA_size(pkey->pkey.rsa) + 16))) {
	ossl_raise(eRSAError, "Memory alloc error");
    }
    buf_len = RSA_private_decrypt(RSTRING(buffer)->len, RSTRING(buffer)->ptr,
				  buf, pkey->pkey.rsa, RSA_PKCS1_PADDING);
    if(buf_len < 0) {
	OPENSSL_free(buf);
	ossl_raise(eRSAError, NULL);
    }
    str = rb_str_new(buf, buf_len);
    OPENSSL_free(buf);

    return str;
}

/*
 * Stores all parameters of key to the hash
 * INSECURE: PRIVATE INFORMATIONS CAN LEAK OUT!!!
 * Don't use :-)) (I's up to you)
 */
static VALUE
ossl_rsa_get_params(VALUE self)
{
    EVP_PKEY *pkey;
    VALUE hash;

    GetPKeyRSA(self, pkey);

    hash = rb_hash_new();

    rb_hash_aset(hash, rb_str_new2("n"), ossl_bn_new(pkey->pkey.rsa->n));
    rb_hash_aset(hash, rb_str_new2("e"), ossl_bn_new(pkey->pkey.rsa->e));
    rb_hash_aset(hash, rb_str_new2("d"), ossl_bn_new(pkey->pkey.rsa->d));
    rb_hash_aset(hash, rb_str_new2("p"), ossl_bn_new(pkey->pkey.rsa->p));
    rb_hash_aset(hash, rb_str_new2("q"), ossl_bn_new(pkey->pkey.rsa->q));
    rb_hash_aset(hash, rb_str_new2("dmp1"), ossl_bn_new(pkey->pkey.rsa->dmp1));
    rb_hash_aset(hash, rb_str_new2("dmq1"), ossl_bn_new(pkey->pkey.rsa->dmq1));
    rb_hash_aset(hash, rb_str_new2("iqmp"), ossl_bn_new(pkey->pkey.rsa->iqmp));
    
    return hash;
}

/*
 * Prints all parameters of key to buffer
 * INSECURE: PRIVATE INFORMATIONS CAN LEAK OUT!!!
 * Don't use :-)) (I's up to you)
 */
static VALUE
ossl_rsa_to_text(VALUE self)
{
    EVP_PKEY *pkey;
    BIO *out;
    BUF_MEM *buf;
    VALUE str;

    GetPKeyRSA(self, pkey);
    if (!(out = BIO_new(BIO_s_mem()))) {
	ossl_raise(eRSAError, NULL);
    }
    if (!RSA_print(out, pkey->pkey.rsa, 0)) { //offset = 0
	BIO_free(out);
	ossl_raise(eRSAError, NULL);
    }
    BIO_get_mem_ptr(out, &buf);
    str = rb_str_new(buf->data, buf->length);
    BIO_free(out);

    return str;
}

/*
 * Makes new instance RSA PUBLIC_KEY from PRIVATE_KEY
 */
static VALUE
ossl_rsa_to_public_key(VALUE self)
{
    EVP_PKEY *pkey;
    RSA *rsa;
    VALUE obj;
    
    GetPKeyRSA(self, pkey);
    /* err check performed by rsa_instance */
    rsa = RSAPublicKey_dup(pkey->pkey.rsa);
    obj = rsa_instance(CLASS_OF(self), rsa);
    if (obj == Qfalse) {
	RSA_free(rsa);
	ossl_raise(eRSAError, NULL);
    }
    return obj;
}

/*
 * TODO: Test me
extern BN_CTX *ossl_bn_ctx;

static VALUE
ossl_rsa_blinding_on(VALUE self)
{
    EVP_PKEY *pkey;
    
    GetPKeyRSA(self, pkey);

    if (RSA_blinding_on(pkey->pkey.rsa, ossl_bn_ctx) != 1) {
	ossl_raise(eRSAError, NULL);
    }
    return self;
}

static VALUE
ossl_rsa_blinding_off(VALUE self)
{
    EVP_PKEY *pkey;
    
    GetPKeyRSA(self, pkey);
    RSA_blinding_off(pkey->pkey.rsa);

    return self;
}
 */

OSSL_PKEY_BN(rsa, n);
OSSL_PKEY_BN(rsa, e);
OSSL_PKEY_BN(rsa, d);
OSSL_PKEY_BN(rsa, p);
OSSL_PKEY_BN(rsa, q);
OSSL_PKEY_BN(rsa, dmp1);
OSSL_PKEY_BN(rsa, dmq1);
OSSL_PKEY_BN(rsa, iqmp);

/*
 * INIT
 */
void
Init_ossl_rsa()
{
    eRSAError = rb_define_class_under(mPKey, "RSAError", ePKeyError);

    cRSA = rb_define_class_under(mPKey, "RSA", cPKey);

    rb_define_singleton_method(cRSA, "generate", ossl_rsa_s_generate, -1);
    rb_define_method(cRSA, "initialize", ossl_rsa_initialize, -1);
	
    rb_define_method(cRSA, "public?", ossl_rsa_is_public, 0);
    rb_define_method(cRSA, "private?", ossl_rsa_is_private, 0);
    rb_define_method(cRSA, "to_text", ossl_rsa_to_text, 0);
    rb_define_method(cRSA, "export", ossl_rsa_export, -1);
    rb_define_alias(cRSA, "to_pem", "export");
    rb_define_alias(cRSA, "to_s", "export");
    rb_define_method(cRSA, "public_key", ossl_rsa_to_public_key, 0);
    rb_define_method(cRSA, "public_encrypt", ossl_rsa_public_encrypt, 1);
    rb_define_method(cRSA, "public_decrypt", ossl_rsa_public_decrypt, 1);
    rb_define_method(cRSA, "private_encrypt", ossl_rsa_private_encrypt, 1);
    rb_define_method(cRSA, "private_decrypt", ossl_rsa_private_decrypt, 1);

    DEF_OSSL_PKEY_BN(cRSA, rsa, n);
    DEF_OSSL_PKEY_BN(cRSA, rsa, e);
    DEF_OSSL_PKEY_BN(cRSA, rsa, d);
    DEF_OSSL_PKEY_BN(cRSA, rsa, p);
    DEF_OSSL_PKEY_BN(cRSA, rsa, q);
    DEF_OSSL_PKEY_BN(cRSA, rsa, dmp1);
    DEF_OSSL_PKEY_BN(cRSA, rsa, dmq1);
    DEF_OSSL_PKEY_BN(cRSA, rsa, iqmp);

    rb_define_method(cRSA, "params", ossl_rsa_get_params, 0);

/*
 * TODO: Test it
    rb_define_method(cRSA, "blinding_on!", ossl_rsa_blinding_on, 0);
    rb_define_method(cRSA, "blinding_off!", ossl_rsa_blinding_off, 0);
 */
}

#else /* defined NO_RSA */
#   warning >>> OpenSSL is compiled without RSA support <<<
void
Init_ossl_rsa()
{
    rb_warning("OpenSSL is compiled without RSA support");
}
#endif /* NO_RSA */