/* $OpenBSD: rsa_ameth.c,v 1.19 2018/08/24 20:22:15 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>

#include <openssl/opensslconf.h>

#include <openssl/asn1t.h>
#include <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <openssl/x509.h>


#include "asn1_locl.h"

static int
rsa_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
{
	unsigned char *penc = NULL;
	int penclen;

	penclen = i2d_RSAPublicKey(pkey->pkey.rsa, &penc);
	if (penclen <= 0)
		return 0;
	if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_RSA),
	    V_ASN1_NULL, NULL, penc, penclen))
		return 1;

	free(penc);
	return 0;
}

static int
rsa_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
{
	const unsigned char *p;
	int pklen;
	RSA *rsa = NULL;

	if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, NULL, pubkey))
		return 0;
	if (!(rsa = d2i_RSAPublicKey(NULL, &p, pklen))) {
		RSAerror(ERR_R_RSA_LIB);
		return 0;
	}
	EVP_PKEY_assign_RSA (pkey, rsa);
	return 1;
}

static int
rsa_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
{
	if (BN_cmp(b->pkey.rsa->n, a->pkey.rsa->n) != 0 ||
	    BN_cmp(b->pkey.rsa->e, a->pkey.rsa->e) != 0)
		return 0;
	return 1;
}

static int
old_rsa_priv_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen)
{
	RSA *rsa;

	if (!(rsa = d2i_RSAPrivateKey (NULL, pder, derlen))) {
		RSAerror(ERR_R_RSA_LIB);
		return 0;
	}
	EVP_PKEY_assign_RSA(pkey, rsa);
	return 1;
}

static int
old_rsa_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
	return i2d_RSAPrivateKey(pkey->pkey.rsa, pder);
}

static int
rsa_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
	unsigned char *rk = NULL;
	int rklen;

	rklen = i2d_RSAPrivateKey(pkey->pkey.rsa, &rk);

	if (rklen <= 0) {
		RSAerror(ERR_R_MALLOC_FAILURE);
		return 0;
	}

	if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_rsaEncryption), 0,
	    V_ASN1_NULL, NULL, rk, rklen)) {
		RSAerror(ERR_R_MALLOC_FAILURE);
		return 0;
	}

	return 1;
}

static int
rsa_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)
{
	const unsigned char *p;
	int pklen;

	if (!PKCS8_pkey_get0(NULL, &p, &pklen, NULL, p8))
		return 0;
	return old_rsa_priv_decode(pkey, &p, pklen);
}

static int
int_rsa_size(const EVP_PKEY *pkey)
{
	return RSA_size(pkey->pkey.rsa);
}

static int
rsa_bits(const EVP_PKEY *pkey)
{
	return BN_num_bits(pkey->pkey.rsa->n);
}

static void
int_rsa_free(EVP_PKEY *pkey)
{
	RSA_free(pkey->pkey.rsa);
}

static void
update_buflen(const BIGNUM *b, size_t *pbuflen)
{
	size_t i;

	if (!b)
		return;
	if (*pbuflen < (i = (size_t)BN_num_bytes(b)))
		*pbuflen = i;
}

static int
do_rsa_print(BIO *bp, const RSA *x, int off, int priv)
{
	char *str;
	const char *s;
	unsigned char *m = NULL;
	int ret = 0, mod_len = 0;
	size_t buf_len = 0;

	update_buflen(x->n, &buf_len);
	update_buflen(x->e, &buf_len);

	if (priv) {
		update_buflen(x->d, &buf_len);
		update_buflen(x->p, &buf_len);
		update_buflen(x->q, &buf_len);
		update_buflen(x->dmp1, &buf_len);
		update_buflen(x->dmq1, &buf_len);
		update_buflen(x->iqmp, &buf_len);
	}

	m = malloc(buf_len + 10);
	if (m == NULL) {
		RSAerror(ERR_R_MALLOC_FAILURE);
		goto err;
	}

	if (x->n != NULL)
		mod_len = BN_num_bits(x->n);

	if (!BIO_indent(bp, off, 128))
		goto err;

	if (priv && x->d) {
		if (BIO_printf(bp, "Private-Key: (%d bit)\n", mod_len) <= 0)
			goto err;
		str = "modulus:";
		s = "publicExponent:";
	} else {
		if (BIO_printf(bp, "Public-Key: (%d bit)\n", mod_len) <= 0)
			goto err;
		str = "Modulus:";
		s= "Exponent:";
	}
	if (!ASN1_bn_print(bp, str, x->n, m, off))
		goto err;
	if (!ASN1_bn_print(bp, s, x->e, m, off))
		goto err;
	if (priv) {
		if (!ASN1_bn_print(bp, "privateExponent:", x->d,m, off))
			goto err;
		if (!ASN1_bn_print(bp, "prime1:", x->p, m, off))
			goto err;
		if (!ASN1_bn_print(bp, "prime2:", x->q, m, off))
			goto err;
		if (!ASN1_bn_print(bp, "exponent1:", x->dmp1, m, off))
			goto err;
		if (!ASN1_bn_print(bp, "exponent2:", x->dmq1, m, off))
			goto err;
		if (!ASN1_bn_print(bp, "coefficient:", x->iqmp, m, off))
			goto err;
	}
	ret = 1;
err:
	free(m);
	return (ret);
}

static int
rsa_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)
{
	return do_rsa_print(bp, pkey->pkey.rsa, indent, 0);
}

static int
rsa_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)
{
	return do_rsa_print(bp, pkey->pkey.rsa, indent, 1);
}

static RSA_PSS_PARAMS *
rsa_pss_decode(const X509_ALGOR *alg, X509_ALGOR **pmaskHash)
{
	const unsigned char *p;
	int plen;
	RSA_PSS_PARAMS *pss;

	*pmaskHash = NULL;

	if (!alg->parameter || alg->parameter->type != V_ASN1_SEQUENCE)
		return NULL;

	p = alg->parameter->value.sequence->data;
	plen = alg->parameter->value.sequence->length;
	pss = d2i_RSA_PSS_PARAMS(NULL, &p, plen);

	if (!pss)
		return NULL;

	if (pss->maskGenAlgorithm) {
		ASN1_TYPE *param = pss->maskGenAlgorithm->parameter;
		if (OBJ_obj2nid(pss->maskGenAlgorithm->algorithm) == NID_mgf1 &&
		    param && param->type == V_ASN1_SEQUENCE) {
			p = param->value.sequence->data;
			plen = param->value.sequence->length;
			*pmaskHash = d2i_X509_ALGOR(NULL, &p, plen);
		}
	}

	return pss;
}

static int
rsa_pss_param_print(BIO *bp, RSA_PSS_PARAMS *pss, X509_ALGOR *maskHash,
    int indent)
{
	int rv = 0;

	if (!pss) {
		if (BIO_puts(bp, " (INVALID PSS PARAMETERS)\n") <= 0)
			return 0;
		return 1;
	}
	if (BIO_puts(bp, "\n") <= 0)
		goto err;
	if (!BIO_indent(bp, indent, 128))
		goto err;
	if (BIO_puts(bp, "Hash Algorithm: ") <= 0)
		goto err;

	if (pss->hashAlgorithm) {
		if (i2a_ASN1_OBJECT(bp, pss->hashAlgorithm->algorithm) <= 0)
			goto err;
	} else if (BIO_puts(bp, "sha1 (default)") <= 0)
		goto err;

	if (BIO_puts(bp, "\n") <= 0)
		goto err;

	if (!BIO_indent(bp, indent, 128))
		goto err;

	if (BIO_puts(bp, "Mask Algorithm: ") <= 0)
		goto err;
	if (pss->maskGenAlgorithm) {
		if (i2a_ASN1_OBJECT(bp, pss->maskGenAlgorithm->algorithm) <= 0)
			goto err;
		if (BIO_puts(bp, " with ") <= 0)
			goto err;
		if (maskHash) {
			if (i2a_ASN1_OBJECT(bp, maskHash->algorithm) <= 0)
				goto err;
		} else if (BIO_puts(bp, "INVALID") <= 0)
			goto err;
	} else if (BIO_puts(bp, "mgf1 with sha1 (default)") <= 0)
		goto err;
	BIO_puts(bp, "\n");

	if (!BIO_indent(bp, indent, 128))
		goto err;
	if (BIO_puts(bp, "Salt Length: 0x") <= 0)
		goto err;
	if (pss->saltLength) {
		if (i2a_ASN1_INTEGER(bp, pss->saltLength) <= 0)
			goto err;
	} else if (BIO_puts(bp, "14 (default)") <= 0)
		goto err;
	BIO_puts(bp, "\n");

	if (!BIO_indent(bp, indent, 128))
		goto err;
	if (BIO_puts(bp, "Trailer Field: 0x") <= 0)
		goto err;
	if (pss->trailerField) {
		if (i2a_ASN1_INTEGER(bp, pss->trailerField) <= 0)
			goto err;
	} else if (BIO_puts(bp, "BC (default)") <= 0)
		goto err;
	BIO_puts(bp, "\n");

	rv = 1;

err:
	return rv;
}

static int
rsa_sig_print(BIO *bp, const X509_ALGOR *sigalg, const ASN1_STRING *sig,
    int indent, ASN1_PCTX *pctx)
{
	if (OBJ_obj2nid(sigalg->algorithm) == NID_rsassaPss) {
		int rv;
		RSA_PSS_PARAMS *pss;
		X509_ALGOR *maskHash;
		pss = rsa_pss_decode(sigalg, &maskHash);
		rv = rsa_pss_param_print(bp, pss, maskHash, indent);
		if (pss)
			RSA_PSS_PARAMS_free(pss);
		if (maskHash)
			X509_ALGOR_free(maskHash);
		if (!rv)
			return 0;
	} else if (!sig && BIO_puts(bp, "\n") <= 0)
		return 0;
	if (sig)
		return X509_signature_dump(bp, sig, indent);
	return 1;
}

static int
rsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
	X509_ALGOR *alg = NULL;

	switch (op) {
	case ASN1_PKEY_CTRL_PKCS7_SIGN:
		if (arg1 == 0)
			PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, NULL, &alg);
		break;

	case ASN1_PKEY_CTRL_PKCS7_ENCRYPT:
		if (arg1 == 0)
			PKCS7_RECIP_INFO_get0_alg(arg2, &alg);
		break;

	case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
		*(int *)arg2 = NID_sha1;
		return 1;

	default:
		return -2;
	}

	if (alg)
		X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption),
		    V_ASN1_NULL, 0);

	return 1;
}

/* Customised RSA item verification routine. This is called
 * when a signature is encountered requiring special handling. We
 * currently only handle PSS.
 */
static int
rsa_item_verify(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
    X509_ALGOR *sigalg, ASN1_BIT_STRING *sig, EVP_PKEY *pkey)
{
	int rv = -1;
	int saltlen;
	const EVP_MD *mgf1md = NULL, *md = NULL;
	RSA_PSS_PARAMS *pss;
	X509_ALGOR *maskHash;
	EVP_PKEY_CTX *pkctx;

	/* Sanity check: make sure it is PSS */
	if (OBJ_obj2nid(sigalg->algorithm) != NID_rsassaPss) {
		RSAerror(RSA_R_UNSUPPORTED_SIGNATURE_TYPE);
		return -1;
	}

	/* Decode PSS parameters */
	pss = rsa_pss_decode(sigalg, &maskHash);

	if (pss == NULL) {
		RSAerror(RSA_R_INVALID_PSS_PARAMETERS);
		goto err;
	}
	/* Check mask and lookup mask hash algorithm */
	if (pss->maskGenAlgorithm) {
		if (OBJ_obj2nid(pss->maskGenAlgorithm->algorithm) != NID_mgf1) {
			RSAerror(RSA_R_UNSUPPORTED_MASK_ALGORITHM);
			goto err;
		}
		if (!maskHash) {
			RSAerror(RSA_R_UNSUPPORTED_MASK_PARAMETER);
			goto err;
		}
		mgf1md = EVP_get_digestbyobj(maskHash->algorithm);
		if (mgf1md == NULL) {
			RSAerror(RSA_R_UNKNOWN_MASK_DIGEST);
			goto err;
		}
	} else
		mgf1md = EVP_sha1();

	if (pss->hashAlgorithm) {
		md = EVP_get_digestbyobj(pss->hashAlgorithm->algorithm);
		if (md == NULL) {
			RSAerror(RSA_R_UNKNOWN_PSS_DIGEST);
			goto err;
		}
	} else
		md = EVP_sha1();

	if (pss->saltLength) {
		saltlen = ASN1_INTEGER_get(pss->saltLength);

		/* Could perform more salt length sanity checks but the main
		 * RSA routines will trap other invalid values anyway.
		 */
		if (saltlen < 0) {
			RSAerror(RSA_R_INVALID_SALT_LENGTH);
			goto err;
		}
	} else
		saltlen = 20;

	/* low-level routines support only trailer field 0xbc (value 1)
	 * and PKCS#1 says we should reject any other value anyway.
	 */
	if (pss->trailerField && ASN1_INTEGER_get(pss->trailerField) != 1) {
		RSAerror(RSA_R_INVALID_TRAILER);
		goto err;
	}

	/* We have all parameters now set up context */

	if (!EVP_DigestVerifyInit(ctx, &pkctx, md, NULL, pkey))
		goto err;

	if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_PSS_PADDING) <= 0)
		goto err;

	if (EVP_PKEY_CTX_set_rsa_pss_saltlen(pkctx, saltlen) <= 0)
		goto err;

	if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)
		goto err;
	/* Carry on */
	rv = 2;

err:
	RSA_PSS_PARAMS_free(pss);
	if (maskHash)
		X509_ALGOR_free(maskHash);
	return rv;
}

static int
rsa_item_sign(EVP_MD_CTX *ctx, const ASN1_ITEM *it, void *asn,
    X509_ALGOR *alg1, X509_ALGOR *alg2, ASN1_BIT_STRING *sig)
{
	int pad_mode;
	EVP_PKEY_CTX *pkctx = ctx->pctx;

	if (EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode) <= 0)
		return 0;
	if (pad_mode == RSA_PKCS1_PADDING)
		return 2;
	if (pad_mode == RSA_PKCS1_PSS_PADDING) {
		const EVP_MD *sigmd, *mgf1md;
		RSA_PSS_PARAMS *pss = NULL;
		X509_ALGOR *mgf1alg = NULL;
		ASN1_STRING *os1 = NULL, *os2 = NULL;
		EVP_PKEY *pk = EVP_PKEY_CTX_get0_pkey(pkctx);
		int saltlen, rv = 0;

		sigmd = EVP_MD_CTX_md(ctx);
		if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) <= 0)
			goto err;
		if (!EVP_PKEY_CTX_get_rsa_pss_saltlen(pkctx, &saltlen))
			goto err;
		if (saltlen == -1)
			saltlen = EVP_MD_size(sigmd);
		else if (saltlen == -2) {
			saltlen = EVP_PKEY_size(pk) - EVP_MD_size(sigmd) - 2;
			if (((EVP_PKEY_bits(pk) - 1) & 0x7) == 0)
				saltlen--;
		}
		pss = RSA_PSS_PARAMS_new();
		if (!pss)
			goto err;
		if (saltlen != 20) {
			pss->saltLength = ASN1_INTEGER_new();
			if (!pss->saltLength)
				goto err;
			if (!ASN1_INTEGER_set(pss->saltLength, saltlen))
				goto err;
		}
		if (EVP_MD_type(sigmd) != NID_sha1) {
			pss->hashAlgorithm = X509_ALGOR_new();
			if (!pss->hashAlgorithm)
				goto err;
			X509_ALGOR_set_md(pss->hashAlgorithm, sigmd);
		}
		if (EVP_MD_type(mgf1md) != NID_sha1) {
			ASN1_STRING *stmp = NULL;
			/* need to embed algorithm ID inside another */
			mgf1alg = X509_ALGOR_new();
			X509_ALGOR_set_md(mgf1alg, mgf1md);
			if (!ASN1_item_pack(mgf1alg, &X509_ALGOR_it,
			    &stmp))
				goto err;
			pss->maskGenAlgorithm = X509_ALGOR_new();
			if (!pss->maskGenAlgorithm)
				goto err;
			X509_ALGOR_set0(pss->maskGenAlgorithm,
			    OBJ_nid2obj(NID_mgf1), V_ASN1_SEQUENCE, stmp);
		}
		/* Finally create string with pss parameter encoding. */
		if (!ASN1_item_pack(pss, &RSA_PSS_PARAMS_it, &os1))
			goto err;
		if (alg2) {
			os2 = ASN1_STRING_dup(os1);
			if (!os2)
				goto err;
			X509_ALGOR_set0(alg2, OBJ_nid2obj(NID_rsassaPss),
			    V_ASN1_SEQUENCE, os2);
		}
		X509_ALGOR_set0(alg1, OBJ_nid2obj(NID_rsassaPss),
		    V_ASN1_SEQUENCE, os1);
		os1 = os2 = NULL;
		rv = 3;
err:
		if (mgf1alg)
			X509_ALGOR_free(mgf1alg);
		if (pss)
			RSA_PSS_PARAMS_free(pss);
		ASN1_STRING_free(os1);
		return rv;
	}
	return 2;
}

const EVP_PKEY_ASN1_METHOD rsa_asn1_meths[] = {
	{
		.pkey_id = EVP_PKEY_RSA,
		.pkey_base_id = EVP_PKEY_RSA,
		.pkey_flags = ASN1_PKEY_SIGPARAM_NULL,

		.pem_str = "RSA",
		.info = "OpenSSL RSA method",

		.pub_decode = rsa_pub_decode,
		.pub_encode = rsa_pub_encode,
		.pub_cmp = rsa_pub_cmp,
		.pub_print = rsa_pub_print,

		.priv_decode = rsa_priv_decode,
		.priv_encode = rsa_priv_encode,
		.priv_print = rsa_priv_print,

		.pkey_size = int_rsa_size,
		.pkey_bits = rsa_bits,

		.sig_print = rsa_sig_print,

		.pkey_free = int_rsa_free,
		.pkey_ctrl = rsa_pkey_ctrl,
		.old_priv_decode = old_rsa_priv_decode,
		.old_priv_encode = old_rsa_priv_encode,
		.item_verify = rsa_item_verify,
		.item_sign = rsa_item_sign
	},

	{
		.pkey_id = EVP_PKEY_RSA2,
		.pkey_base_id = EVP_PKEY_RSA,
		.pkey_flags = ASN1_PKEY_ALIAS
	}
};
