/*

 * Copyright 2006-2023 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <assert.h>

#include <openssl/cms.h>

#include <openssl/err.h>

#include <openssl/core_names.h>

#include "crypto/asn1.h"

#include "crypto/rsa.h"

#include "crypto/evp.h"

#include "cms_local.h"

static RSA_OAEP_PARAMS *rsa_oaep_decode(const X509_ALGOR *alg)

{

    RSA_OAEP_PARAMS *oaep;

    oaep = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(RSA_OAEP_PARAMS),

                                     alg->parameter);

    if (oaep == NULL)

        return NULL;

    if (oaep->maskGenFunc != NULL) {

        oaep->maskHash = ossl_x509_algor_mgf1_decode(oaep->maskGenFunc);

        if (oaep->maskHash == NULL) {

            RSA_OAEP_PARAMS_free(oaep);

            return NULL;

        }

    }

    return oaep;

}

static int rsa_cms_decrypt(CMS_RecipientInfo *ri)

{

    EVP_PKEY_CTX *pkctx;

    X509_ALGOR *cmsalg;

    int nid;

    int rv = -1;

    unsigned char *label = NULL;

    int labellen = 0;

    const EVP_MD *mgf1md = NULL, *md = NULL;

    RSA_OAEP_PARAMS *oaep;

    pkctx = CMS_RecipientInfo_get0_pkey_ctx(ri);

    if (pkctx == NULL)

        return 0;

    if (!CMS_RecipientInfo_ktri_get0_algs(ri, NULL, NULL, &cmsalg))

        return -1;

    nid = OBJ_obj2nid(cmsalg->algorithm);

    if (nid == NID_rsaEncryption)

        return 1;

    if (nid != NID_rsaesOaep) {

        ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_ENCRYPTION_TYPE);

        return -1;

    }

    /* Decode OAEP parameters */

    oaep = rsa_oaep_decode(cmsalg);

    if (oaep == NULL) {

        ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_OAEP_PARAMETERS);

        goto err;

    }

    mgf1md = ossl_x509_algor_get_md(oaep->maskHash);

    if (mgf1md == NULL)

        goto err;

    md = ossl_x509_algor_get_md(oaep->hashFunc);

    if (md == NULL)

        goto err;

    if (oaep->pSourceFunc != NULL) {

        X509_ALGOR *plab = oaep->pSourceFunc;

        if (OBJ_obj2nid(plab->algorithm) != NID_pSpecified) {

            ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_LABEL_SOURCE);

            goto err;

        }

        if (plab->parameter->type != V_ASN1_OCTET_STRING) {

            ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_LABEL);

            goto err;

        }

        label = plab->parameter->value.octet_string->data;

        /* Stop label being freed when OAEP parameters are freed */

        plab->parameter->value.octet_string->data = NULL;

        labellen = plab->parameter->value.octet_string->length;

    }

    if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_OAEP_PADDING) <= 0)

        goto err;

    if (EVP_PKEY_CTX_set_rsa_oaep_md(pkctx, md) <= 0)

        goto err;

    if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)

        goto err;

    if (label != NULL

            && EVP_PKEY_CTX_set0_rsa_oaep_label(pkctx, label, labellen) <= 0)

        goto err;

    /* Carry on */

    rv = 1;

 err:

    RSA_OAEP_PARAMS_free(oaep);

    return rv;

}

static int rsa_cms_encrypt(CMS_RecipientInfo *ri)

{

    const EVP_MD *md, *mgf1md;

    RSA_OAEP_PARAMS *oaep = NULL;

    ASN1_STRING *os = NULL;

    X509_ALGOR *alg;

    EVP_PKEY_CTX *pkctx = CMS_RecipientInfo_get0_pkey_ctx(ri);

    int pad_mode = RSA_PKCS1_PADDING, rv = 0, labellen;

    unsigned char *label;

    if (CMS_RecipientInfo_ktri_get0_algs(ri, NULL, NULL, &alg) <= 0)

        return 0;

    if (pkctx != NULL) {

        if (EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode) <= 0)

            return 0;

    }

    if (pad_mode == RSA_PKCS1_PADDING)

        return X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption),

                               V_ASN1_NULL, NULL);

    /* Not supported */

    if (pad_mode != RSA_PKCS1_OAEP_PADDING)

        return 0;

    if (EVP_PKEY_CTX_get_rsa_oaep_md(pkctx, &md) <= 0)

        goto err;

    if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) <= 0)

        goto err;

    labellen = EVP_PKEY_CTX_get0_rsa_oaep_label(pkctx, &label);

    if (labellen < 0)

        goto err;

    oaep = RSA_OAEP_PARAMS_new();

    if (oaep == NULL)

        goto err;

    if (!ossl_x509_algor_new_from_md(&oaep->hashFunc, md))

        goto err;

    if (!ossl_x509_algor_md_to_mgf1(&oaep->maskGenFunc, mgf1md))

        goto err;

    if (labellen > 0) {

        ASN1_OCTET_STRING *los = ASN1_OCTET_STRING_new();

        if (los == NULL)

            goto err;

        if (!ASN1_OCTET_STRING_set(los, label, labellen)) {

            ASN1_OCTET_STRING_free(los);

            goto err;

        }

        oaep->pSourceFunc = ossl_X509_ALGOR_from_nid(NID_pSpecified,

                                                     V_ASN1_OCTET_STRING, los);

        if (oaep->pSourceFunc == NULL)

            goto err;

    }

    /* create string with pss parameter encoding. */

    if (!ASN1_item_pack(oaep, ASN1_ITEM_rptr(RSA_OAEP_PARAMS), &os))

        goto err;

    if (!X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaesOaep), V_ASN1_SEQUENCE, os))

        goto err;

    os = NULL;

    rv = 1;

 err:

    RSA_OAEP_PARAMS_free(oaep);

    ASN1_STRING_free(os);

    return rv;

}

int ossl_cms_rsa_envelope(CMS_RecipientInfo *ri, int decrypt)

{

    assert(decrypt == 0 || decrypt == 1);

    if (decrypt == 1)

        return rsa_cms_decrypt(ri);

    if (decrypt == 0)

        return rsa_cms_encrypt(ri);

    ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);

    return 0;

}

static int rsa_cms_sign(CMS_SignerInfo *si)

{

    int pad_mode = RSA_PKCS1_PADDING;

    X509_ALGOR *alg;

    EVP_PKEY_CTX *pkctx = CMS_SignerInfo_get0_pkey_ctx(si);

    unsigned char aid[128];

    const unsigned char *pp = aid;

    size_t aid_len = 0;

    OSSL_PARAM params[2];

    CMS_SignerInfo_get0_algs(si, NULL, NULL, NULL, &alg);

    if (pkctx != NULL) {

        if (EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode) <= 0)

            return 0;

    }

    if (pad_mode == RSA_PKCS1_PADDING)

        return X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption),

                               V_ASN1_NULL, NULL);

    /* We don't support it */

    if (pad_mode != RSA_PKCS1_PSS_PADDING)

        return 0;

    if (evp_pkey_ctx_is_legacy(pkctx)) {

        /* No provider -> we cannot query it for algorithm ID. */

        ASN1_STRING *os = NULL;

        os = ossl_rsa_ctx_to_pss_string(pkctx);

        if (os == NULL)

            return 0;

        return X509_ALGOR_set0(alg, OBJ_nid2obj(EVP_PKEY_RSA_PSS), V_ASN1_SEQUENCE, os);

    }

    params[0] = OSSL_PARAM_construct_octet_string(

        OSSL_SIGNATURE_PARAM_ALGORITHM_ID, aid, sizeof(aid));

    params[1] = OSSL_PARAM_construct_end();

    if (EVP_PKEY_CTX_get_params(pkctx, params) <= 0)

        return 0;

    if ((aid_len = params[0].return_size) == 0)

        return 0;

    if (d2i_X509_ALGOR(&alg, &pp, aid_len) == NULL)

        return 0;

    return 1;

}

static int rsa_cms_verify(CMS_SignerInfo *si)

{

    int nid, nid2;

    X509_ALGOR *alg;

    EVP_PKEY_CTX *pkctx = CMS_SignerInfo_get0_pkey_ctx(si);

    EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(pkctx);

    CMS_SignerInfo_get0_algs(si, NULL, NULL, NULL, &alg);

    nid = OBJ_obj2nid(alg->algorithm);

    if (nid == EVP_PKEY_RSA_PSS)

        return ossl_rsa_pss_to_ctx(NULL, pkctx, alg, NULL) > 0;

    /* Only PSS allowed for PSS keys */

    if (EVP_PKEY_is_a(pkey, "RSA-PSS")) {

        ERR_raise(ERR_LIB_RSA, RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);

        return 0;

    }

    if (nid == NID_rsaEncryption)

        return 1;

    /* Workaround for some implementation that use a signature OID */

    if (OBJ_find_sigid_algs(nid, NULL, &nid2)) {

        if (nid2 == NID_rsaEncryption)

            return 1;

    }

    return 0;

}

int ossl_cms_rsa_sign(CMS_SignerInfo *si, int verify)

{

    assert(verify == 0 || verify == 1);

    if (verify == 1)

        return rsa_cms_verify(si);

    if (verify == 0)

        return rsa_cms_sign(si);

    ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);

    return 0;

}