/*

 * Copyright 1995-2023 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 <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/objects.h>

#include <openssl/x509.h>

#include <openssl/pkcs7.h>

#include "crypto/asn1.h"

#include "crypto/evp.h"

#include "crypto/x509.h" /* for sk_X509_add1_cert() */

#include "pk7_local.h"

long PKCS7_ctrl(PKCS7 *p7, int cmd, long larg, char *parg)

{

    int nid;

    long ret;

    nid = OBJ_obj2nid(p7->type);

    switch (cmd) {

    /* NOTE(emilia): does not support detached digested data. */

    case PKCS7_OP_SET_DETACHED_SIGNATURE:

        if (nid == NID_pkcs7_signed) {

            if (p7->d.sign == NULL) {

                ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);

                ret = 0;

                break;

            }

            ret = p7->detached = (int)larg;

            if (ret && PKCS7_type_is_data(p7->d.sign->contents)) {

                ASN1_OCTET_STRING *os;

                os = p7->d.sign->contents->d.data;

                ASN1_OCTET_STRING_free(os);

                p7->d.sign->contents->d.data = NULL;

            }

        } else {

            ERR_raise(ERR_LIB_PKCS7,

                PKCS7_R_OPERATION_NOT_SUPPORTED_ON_THIS_TYPE);

            ret = 0;

        }

        break;

    case PKCS7_OP_GET_DETACHED_SIGNATURE:

        if (nid == NID_pkcs7_signed) {

            if (p7->d.sign == NULL || p7->d.sign->contents == NULL

                    || p7->d.sign->contents->d.ptr == NULL)

                ret = 1;

            else

                ret = 0;

            p7->detached = ret;

        } else {

            ERR_raise(ERR_LIB_PKCS7,

                PKCS7_R_OPERATION_NOT_SUPPORTED_ON_THIS_TYPE);

            ret = 0;

        }

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNKNOWN_OPERATION);

        ret = 0;

    }

    return ret;

}

int PKCS7_content_new(PKCS7 *p7, int type)

{

    PKCS7 *ret = NULL;

    if ((ret = PKCS7_new()) == NULL)

        goto err;

    if (!PKCS7_set_type(ret, type))

        goto err;

    if (!PKCS7_set_content(p7, ret))

        goto err;

    return 1;

err:

    PKCS7_free(ret);

    return 0;

}

int PKCS7_set_content(PKCS7 *p7, PKCS7 *p7_data)

{

    int i;

    i = OBJ_obj2nid(p7->type);

    switch (i) {

    case NID_pkcs7_signed:

        PKCS7_free(p7->d.sign->contents);

        p7->d.sign->contents = p7_data;

        break;

    case NID_pkcs7_digest:

        PKCS7_free(p7->d.digest->contents);

        p7->d.digest->contents = p7_data;

        break;

    case NID_pkcs7_data:

    case NID_pkcs7_enveloped:

    case NID_pkcs7_signedAndEnveloped:

    case NID_pkcs7_encrypted:

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);

        goto err;

    }

    return 1;

err:

    return 0;

}

int PKCS7_set_type(PKCS7 *p7, int type)

{

    ASN1_OBJECT *obj;

    /*

     * PKCS7_content_free(p7);

     */

    obj = OBJ_nid2obj(type); /* will not fail */

    switch (type) {

    case NID_pkcs7_signed:

        p7->type = obj;

        if ((p7->d.sign = PKCS7_SIGNED_new()) == NULL)

            goto err;

        if (!ASN1_INTEGER_set(p7->d.sign->version, 1)) {

            PKCS7_SIGNED_free(p7->d.sign);

            p7->d.sign = NULL;

            goto err;

        }

        break;

    case NID_pkcs7_data:

        p7->type = obj;

        if ((p7->d.data = ASN1_OCTET_STRING_new()) == NULL)

            goto err;

        break;

    case NID_pkcs7_signedAndEnveloped:

        p7->type = obj;

        if ((p7->d.signed_and_enveloped = PKCS7_SIGN_ENVELOPE_new())

            == NULL)

            goto err;

        if (!ASN1_INTEGER_set(p7->d.signed_and_enveloped->version, 1))

            goto err;

        p7->d.signed_and_enveloped->enc_data->content_type

            = OBJ_nid2obj(NID_pkcs7_data);

        break;

    case NID_pkcs7_enveloped:

        p7->type = obj;

        if ((p7->d.enveloped = PKCS7_ENVELOPE_new())

            == NULL)

            goto err;

        if (!ASN1_INTEGER_set(p7->d.enveloped->version, 0))

            goto err;

        p7->d.enveloped->enc_data->content_type = OBJ_nid2obj(NID_pkcs7_data);

        break;

    case NID_pkcs7_encrypted:

        p7->type = obj;

        if ((p7->d.encrypted = PKCS7_ENCRYPT_new())

            == NULL)

            goto err;

        if (!ASN1_INTEGER_set(p7->d.encrypted->version, 0))

            goto err;

        p7->d.encrypted->enc_data->content_type = OBJ_nid2obj(NID_pkcs7_data);

        break;

    case NID_pkcs7_digest:

        p7->type = obj;

        if ((p7->d.digest = PKCS7_DIGEST_new())

            == NULL)

            goto err;

        if (!ASN1_INTEGER_set(p7->d.digest->version, 0))

            goto err;

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);

        goto err;

    }

    return 1;

err:

    return 0;

}

int PKCS7_set0_type_other(PKCS7 *p7, int type, ASN1_TYPE *other)

{

    p7->type = OBJ_nid2obj(type);

    p7->d.other = other;

    return 1;

}

int PKCS7_add_signer(PKCS7 *p7, PKCS7_SIGNER_INFO *psi)

{

    int i, j;

    ASN1_OBJECT *obj;

    X509_ALGOR *alg;

    STACK_OF(PKCS7_SIGNER_INFO) *signer_sk;

    STACK_OF(X509_ALGOR) *md_sk;

    i = OBJ_obj2nid(p7->type);

    switch (i) {

    case NID_pkcs7_signed:

        signer_sk = p7->d.sign->signer_info;

        md_sk = p7->d.sign->md_algs;

        break;

    case NID_pkcs7_signedAndEnveloped:

        signer_sk = p7->d.signed_and_enveloped->signer_info;

        md_sk = p7->d.signed_and_enveloped->md_algs;

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_CONTENT_TYPE);

        return 0;

    }

    obj = psi->digest_alg->algorithm;

    /* If the digest is not currently listed, add it */

    j = 0;

    for (i = 0; i < sk_X509_ALGOR_num(md_sk); i++) {

        alg = sk_X509_ALGOR_value(md_sk, i);

        if (OBJ_cmp(obj, alg->algorithm) == 0) {

            j = 1;

            break;

        }

    }

    if (!j) { /* we need to add another algorithm */

        int nid;

        if ((alg = X509_ALGOR_new()) == NULL

            || (alg->parameter = ASN1_TYPE_new()) == NULL) {

            X509_ALGOR_free(alg);

            ERR_raise(ERR_LIB_PKCS7, ERR_R_ASN1_LIB);

            return 0;

        }

        /*

         * If there is a constant copy of the ASN1 OBJECT in libcrypto, then

         * use that.  Otherwise, use a dynamically duplicated copy

         */

        if ((nid = OBJ_obj2nid(obj)) != NID_undef)

            alg->algorithm = OBJ_nid2obj(nid);

        else

            alg->algorithm = OBJ_dup(obj);

        alg->parameter->type = V_ASN1_NULL;

        if (alg->algorithm == NULL || !sk_X509_ALGOR_push(md_sk, alg)) {

            X509_ALGOR_free(alg);

            return 0;

        }

    }

    psi->ctx = ossl_pkcs7_get0_ctx(p7);

    if (!sk_PKCS7_SIGNER_INFO_push(signer_sk, psi))

        return 0;

    return 1;

}

int PKCS7_add_certificate(PKCS7 *p7, X509 *x509)

{

    int i;

    STACK_OF(X509) **sk;

    i = OBJ_obj2nid(p7->type);

    switch (i) {

    case NID_pkcs7_signed:

        sk = &(p7->d.sign->cert);

        break;

    case NID_pkcs7_signedAndEnveloped:

        sk = &(p7->d.signed_and_enveloped->cert);

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_CONTENT_TYPE);

        return 0;

    }

    return ossl_x509_add_cert_new(sk, x509, X509_ADD_FLAG_UP_REF);

}

int PKCS7_add_crl(PKCS7 *p7, X509_CRL *crl)

{

    int i;

    STACK_OF(X509_CRL) **sk;

    i = OBJ_obj2nid(p7->type);

    switch (i) {

    case NID_pkcs7_signed:

        sk = &(p7->d.sign->crl);

        break;

    case NID_pkcs7_signedAndEnveloped:

        sk = &(p7->d.signed_and_enveloped->crl);

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_CONTENT_TYPE);

        return 0;

    }

    if (*sk == NULL)

        *sk = sk_X509_CRL_new_null();

    if (*sk == NULL) {

        ERR_raise(ERR_LIB_PKCS7, ERR_R_CRYPTO_LIB);

        return 0;

    }

    X509_CRL_up_ref(crl);

    if (!sk_X509_CRL_push(*sk, crl)) {

        X509_CRL_free(crl);

        return 0;

    }

    return 1;

}

static int pkcs7_ecdsa_or_dsa_sign_verify_setup(PKCS7_SIGNER_INFO *si,

    int verify)

{

    if (!verify) {

        int snid, hnid;

        X509_ALGOR *alg1, *alg2;

        EVP_PKEY *pkey = si->pkey;

        PKCS7_SIGNER_INFO_get0_algs(si, NULL, &alg1, &alg2);

        if (alg1 == NULL || alg1->algorithm == NULL)

            return -1;

        hnid = OBJ_obj2nid(alg1->algorithm);

        if (hnid == NID_undef)

            return -1;

        if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_get_id(pkey)))

            return -1;

        return X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, NULL);

    }

    return 1;

}

static int pkcs7_rsa_sign_verify_setup(PKCS7_SIGNER_INFO *si, int verify)

{

    if (!verify) {

        X509_ALGOR *alg = NULL;

        PKCS7_SIGNER_INFO_get0_algs(si, NULL, NULL, &alg);

        if (alg != NULL)

            return X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption),

                V_ASN1_NULL, NULL);

    }

    return 1;

}

int PKCS7_SIGNER_INFO_set(PKCS7_SIGNER_INFO *p7i, X509 *x509, EVP_PKEY *pkey,

    const EVP_MD *dgst)

{

    int ret;

    /* We now need to add another PKCS7_SIGNER_INFO entry */

    if (!ASN1_INTEGER_set(p7i->version, 1))

        return 0;

    if (!X509_NAME_set(&p7i->issuer_and_serial->issuer,

            X509_get_issuer_name(x509)))

        return 0;

    /*

     * because ASN1_INTEGER_set is used to set a 'long' we will do things the

     * ugly way.

     */

    ASN1_INTEGER_free(p7i->issuer_and_serial->serial);

    if (!(p7i->issuer_and_serial->serial = ASN1_INTEGER_dup(X509_get0_serialNumber(x509))))

        return 0;

    /* lets keep the pkey around for a while */

    EVP_PKEY_up_ref(pkey);

    p7i->pkey = pkey;

    /* Set the algorithms */

    if (!X509_ALGOR_set0(p7i->digest_alg, OBJ_nid2obj(EVP_MD_get_type(dgst)),

            V_ASN1_NULL, NULL))

        return 0;

    if (EVP_PKEY_is_a(pkey, "EC") || EVP_PKEY_is_a(pkey, "DSA"))

        return pkcs7_ecdsa_or_dsa_sign_verify_setup(p7i, 0);

    if (EVP_PKEY_is_a(pkey, "RSA"))

        return pkcs7_rsa_sign_verify_setup(p7i, 0);

    if (pkey->ameth != NULL && pkey->ameth->pkey_ctrl != NULL) {

        ret = pkey->ameth->pkey_ctrl(pkey, ASN1_PKEY_CTRL_PKCS7_SIGN, 0, p7i);

        if (ret > 0)

            return 1;

        if (ret != -2) {

            ERR_raise(ERR_LIB_PKCS7, PKCS7_R_SIGNING_CTRL_FAILURE);

            return 0;

        }

    }

    ERR_raise(ERR_LIB_PKCS7, PKCS7_R_SIGNING_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);

    return 0;

}

PKCS7_SIGNER_INFO *PKCS7_add_signature(PKCS7 *p7, X509 *x509, EVP_PKEY *pkey,

    const EVP_MD *dgst)

{

    PKCS7_SIGNER_INFO *si = NULL;

    if (dgst == NULL) {

        int def_nid;

        if (EVP_PKEY_get_default_digest_nid(pkey, &def_nid) <= 0)

            goto err;

        dgst = EVP_get_digestbynid(def_nid);

        if (dgst == NULL) {

            ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_DEFAULT_DIGEST);

            goto err;

        }

    }

    if ((si = PKCS7_SIGNER_INFO_new()) == NULL)

        goto err;

    if (PKCS7_SIGNER_INFO_set(si, x509, pkey, dgst) <= 0)

        goto err;

    if (!PKCS7_add_signer(p7, si))

        goto err;

    return si;

err:

    PKCS7_SIGNER_INFO_free(si);

    return NULL;

}

static STACK_OF(X509) *pkcs7_get_signer_certs(const PKCS7 *p7)

{

    if (p7->d.ptr == NULL)

        return NULL;

    if (PKCS7_type_is_signed(p7))

        return p7->d.sign->cert;

    if (PKCS7_type_is_signedAndEnveloped(p7))

        return p7->d.signed_and_enveloped->cert;

    return NULL;

}

static STACK_OF(PKCS7_RECIP_INFO) *pkcs7_get_recipient_info(const PKCS7 *p7)

{

    if (p7->d.ptr == NULL)

        return NULL;

    if (PKCS7_type_is_signedAndEnveloped(p7))

        return p7->d.signed_and_enveloped->recipientinfo;

    if (PKCS7_type_is_enveloped(p7))

        return p7->d.enveloped->recipientinfo;

    return NULL;

}

/*

 * Set up the library context into any loaded structure that needs it.

 * i.e loaded X509 objects.

 */

void ossl_pkcs7_resolve_libctx(PKCS7 *p7)

{

    int i;

    const PKCS7_CTX *ctx = ossl_pkcs7_get0_ctx(p7);

    OSSL_LIB_CTX *libctx = ossl_pkcs7_ctx_get0_libctx(ctx);

    const char *propq = ossl_pkcs7_ctx_get0_propq(ctx);

    STACK_OF(PKCS7_RECIP_INFO) *rinfos;

    STACK_OF(PKCS7_SIGNER_INFO) *sinfos;

    STACK_OF(X509) *certs;

    if (ctx == NULL || p7->d.ptr == NULL)

        return;

    rinfos = pkcs7_get_recipient_info(p7);

    sinfos = PKCS7_get_signer_info(p7);

    certs = pkcs7_get_signer_certs(p7);

    for (i = 0; i < sk_X509_num(certs); i++)

        ossl_x509_set0_libctx(sk_X509_value(certs, i), libctx, propq);

    for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rinfos); i++) {

        PKCS7_RECIP_INFO *ri = sk_PKCS7_RECIP_INFO_value(rinfos, i);

        ossl_x509_set0_libctx(ri->cert, libctx, propq);

    }

    for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(sinfos); i++) {

        PKCS7_SIGNER_INFO *si = sk_PKCS7_SIGNER_INFO_value(sinfos, i);

        if (si != NULL)

            si->ctx = ctx;

    }

}

const PKCS7_CTX *ossl_pkcs7_get0_ctx(const PKCS7 *p7)

{

    return p7 != NULL ? &p7->ctx : NULL;

}

void ossl_pkcs7_set0_libctx(PKCS7 *p7, OSSL_LIB_CTX *ctx)

{

    p7->ctx.libctx = ctx;

}

int ossl_pkcs7_set1_propq(PKCS7 *p7, const char *propq)

{

    if (p7->ctx.propq != NULL) {

        OPENSSL_free(p7->ctx.propq);

        p7->ctx.propq = NULL;

    }

    if (propq != NULL) {

        p7->ctx.propq = OPENSSL_strdup(propq);

        if (p7->ctx.propq == NULL)

            return 0;

    }

    return 1;

}

int ossl_pkcs7_ctx_propagate(const PKCS7 *from, PKCS7 *to)

{

    ossl_pkcs7_set0_libctx(to, from->ctx.libctx);

    if (!ossl_pkcs7_set1_propq(to, from->ctx.propq))

        return 0;

    ossl_pkcs7_resolve_libctx(to);

    return 1;

}

OSSL_LIB_CTX *ossl_pkcs7_ctx_get0_libctx(const PKCS7_CTX *ctx)

{

    return ctx != NULL ? ctx->libctx : NULL;

}

const char *ossl_pkcs7_ctx_get0_propq(const PKCS7_CTX *ctx)

{

    return ctx != NULL ? ctx->propq : NULL;

}

int PKCS7_set_digest(PKCS7 *p7, const EVP_MD *md)

{

    if (PKCS7_type_is_digest(p7)) {

        if ((p7->d.digest->md->parameter = ASN1_TYPE_new()) == NULL) {

            ERR_raise(ERR_LIB_PKCS7, ERR_R_ASN1_LIB);

            return 0;

        }

        p7->d.digest->md->parameter->type = V_ASN1_NULL;

        p7->d.digest->md->algorithm = OBJ_nid2obj(EVP_MD_nid(md));

        return 1;

    }

    ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_CONTENT_TYPE);

    return 1;

}

STACK_OF(PKCS7_SIGNER_INFO) *PKCS7_get_signer_info(PKCS7 *p7)

{

    if (p7 == NULL || p7->d.ptr == NULL)

        return NULL;

    if (PKCS7_type_is_signed(p7)) {

        return p7->d.sign->signer_info;

    } else if (PKCS7_type_is_signedAndEnveloped(p7)) {

        return p7->d.signed_and_enveloped->signer_info;

    } else

        return NULL;

}

void PKCS7_SIGNER_INFO_get0_algs(PKCS7_SIGNER_INFO *si, EVP_PKEY **pk,

    X509_ALGOR **pdig, X509_ALGOR **psig)

{

    if (pk)

        *pk = si->pkey;

    if (pdig)

        *pdig = si->digest_alg;

    if (psig)

        *psig = si->digest_enc_alg;

}

void PKCS7_RECIP_INFO_get0_alg(PKCS7_RECIP_INFO *ri, X509_ALGOR **penc)

{

    if (penc)

        *penc = ri->key_enc_algor;

}

PKCS7_RECIP_INFO *PKCS7_add_recipient(PKCS7 *p7, X509 *x509)

{

    PKCS7_RECIP_INFO *ri;

    if ((ri = PKCS7_RECIP_INFO_new()) == NULL)

        goto err;

    if (PKCS7_RECIP_INFO_set(ri, x509) <= 0)

        goto err;

    if (!PKCS7_add_recipient_info(p7, ri))

        goto err;

    ri->ctx = ossl_pkcs7_get0_ctx(p7);

    return ri;

err:

    PKCS7_RECIP_INFO_free(ri);

    return NULL;

}

int PKCS7_add_recipient_info(PKCS7 *p7, PKCS7_RECIP_INFO *ri)

{

    int i;

    STACK_OF(PKCS7_RECIP_INFO) *sk;

    i = OBJ_obj2nid(p7->type);

    switch (i) {

    case NID_pkcs7_signedAndEnveloped:

        sk = p7->d.signed_and_enveloped->recipientinfo;

        break;

    case NID_pkcs7_enveloped:

        sk = p7->d.enveloped->recipientinfo;

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_CONTENT_TYPE);

        return 0;

    }

    if (!sk_PKCS7_RECIP_INFO_push(sk, ri))

        return 0;

    return 1;

}

static int pkcs7_rsa_encrypt_decrypt_setup(PKCS7_RECIP_INFO *ri, int decrypt)

{

    X509_ALGOR *alg = NULL;

    if (!decrypt) {

        PKCS7_RECIP_INFO_get0_alg(ri, &alg);

        if (alg != NULL)

            return X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption),

                V_ASN1_NULL, NULL);

    }

    return 1;

}

int PKCS7_RECIP_INFO_set(PKCS7_RECIP_INFO *p7i, X509 *x509)

{

    int ret;

    EVP_PKEY *pkey = NULL;

    if (!ASN1_INTEGER_set(p7i->version, 0))

        return 0;

    if (!X509_NAME_set(&p7i->issuer_and_serial->issuer,

            X509_get_issuer_name(x509)))

        return 0;

    ASN1_INTEGER_free(p7i->issuer_and_serial->serial);

    if (!(p7i->issuer_and_serial->serial = ASN1_INTEGER_dup(X509_get0_serialNumber(x509))))

        return 0;

    pkey = X509_get0_pubkey(x509);

    if (pkey == NULL)

        return 0;

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

        return -2;

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

        if (pkcs7_rsa_encrypt_decrypt_setup(p7i, 0) <= 0)

            goto err;

        goto finished;

    }

    if (pkey->ameth == NULL || pkey->ameth->pkey_ctrl == NULL) {

        ERR_raise(ERR_LIB_PKCS7,

            PKCS7_R_ENCRYPTION_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);

        goto err;

    }

    ret = pkey->ameth->pkey_ctrl(pkey, ASN1_PKEY_CTRL_PKCS7_ENCRYPT, 0, p7i);

    if (ret == -2) {

        ERR_raise(ERR_LIB_PKCS7,

            PKCS7_R_ENCRYPTION_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);

        goto err;

    }

    if (ret <= 0) {

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_ENCRYPTION_CTRL_FAILURE);

        goto err;

    }

finished:

    X509_up_ref(x509);

    p7i->cert = x509;

    return 1;

err:

    return 0;

}

X509 *PKCS7_cert_from_signer_info(PKCS7 *p7, PKCS7_SIGNER_INFO *si)

{

    if (PKCS7_type_is_signed(p7))

        return (X509_find_by_issuer_and_serial(p7->d.sign->cert,

            si->issuer_and_serial->issuer,

            si->issuer_and_serial->serial));

    else

        return NULL;

}

int PKCS7_set_cipher(PKCS7 *p7, const EVP_CIPHER *cipher)

{

    int i;

    PKCS7_ENC_CONTENT *ec;

    i = OBJ_obj2nid(p7->type);

    switch (i) {

    case NID_pkcs7_signedAndEnveloped:

        ec = p7->d.signed_and_enveloped->enc_data;

        break;

    case NID_pkcs7_enveloped:

        ec = p7->d.enveloped->enc_data;

        break;

    default:

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_CONTENT_TYPE);

        return 0;

    }

    /* Check cipher OID exists and has data in it */

    i = EVP_CIPHER_get_type(cipher);

    if (i == NID_undef) {

        ERR_raise(ERR_LIB_PKCS7, PKCS7_R_CIPHER_HAS_NO_OBJECT_IDENTIFIER);

        return 0;

    }

    ec->cipher = cipher;

    ec->ctx = ossl_pkcs7_get0_ctx(p7);

    return 1;

}

/* unfortunately cannot constify BIO_new_NDEF() due to this and CMS_stream() */

int PKCS7_stream(unsigned char ***boundary, PKCS7 *p7)

{

    ASN1_OCTET_STRING *os = NULL;

    switch (OBJ_obj2nid(p7->type)) {

    case NID_pkcs7_data:

        os = p7->d.data;

        break;

    case NID_pkcs7_signedAndEnveloped:

        os = p7->d.signed_and_enveloped->enc_data->enc_data;

        if (os == NULL) {

            os = ASN1_OCTET_STRING_new();

            p7->d.signed_and_enveloped->enc_data->enc_data = os;

        }

        break;

    case NID_pkcs7_enveloped:

        os = p7->d.enveloped->enc_data->enc_data;

        if (os == NULL) {

            os = ASN1_OCTET_STRING_new();

            p7->d.enveloped->enc_data->enc_data = os;

        }

        break;

    case NID_pkcs7_signed:

        if (p7->d.sign == NULL || p7->d.sign->contents == NULL) {

            ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);

            break;

        }

        os = p7->d.sign->contents->d.data;

        break;

    default:

        os = NULL;

        break;

    }

    if (os == NULL)

        return 0;

    os->flags |= ASN1_STRING_FLAG_NDEF;

    *boundary = &os->data;

    return 1;

}