/* crypto/pkcs7/pk7_doit.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * 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 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 acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/rand.h>
#include <openssl/objects.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/err.h>

static int add_attribute(STACK_OF(X509_ATTRIBUTE) **sk, int nid, int atrtype,
                         void *value);
static ASN1_TYPE *get_attribute(STACK_OF(X509_ATTRIBUTE) *sk, int nid);

static int PKCS7_type_is_other(PKCS7 *p7)
{
    int isOther = 1;

    int nid = OBJ_obj2nid(p7->type);

    switch (nid) {
    case NID_pkcs7_data:
    case NID_pkcs7_signed:
    case NID_pkcs7_enveloped:
    case NID_pkcs7_signedAndEnveloped:
    case NID_pkcs7_digest:
    case NID_pkcs7_encrypted:
        isOther = 0;
        break;
    default:
        isOther = 1;
    }

    return isOther;

}

static ASN1_OCTET_STRING *PKCS7_get_octet_string(PKCS7 *p7)
{
    if (PKCS7_type_is_data(p7))
        return p7->d.data;
    if (PKCS7_type_is_other(p7) && p7->d.other
        && (p7->d.other->type == V_ASN1_OCTET_STRING))
        return p7->d.other->value.octet_string;
    return NULL;
}

static int PKCS7_bio_add_digest(BIO **pbio, X509_ALGOR *alg)
{
    BIO *btmp;
    const EVP_MD *md;
    if ((btmp = BIO_new(BIO_f_md())) == NULL) {
        PKCS7err(PKCS7_F_PKCS7_BIO_ADD_DIGEST, ERR_R_BIO_LIB);
        goto err;
    }

    md = EVP_get_digestbyobj(alg->algorithm);
    if (md == NULL) {
        PKCS7err(PKCS7_F_PKCS7_BIO_ADD_DIGEST, PKCS7_R_UNKNOWN_DIGEST_TYPE);
        goto err;
    }

    BIO_set_md(btmp, md);
    if (*pbio == NULL)
        *pbio = btmp;
    else if (!BIO_push(*pbio, btmp)) {
        PKCS7err(PKCS7_F_PKCS7_BIO_ADD_DIGEST, ERR_R_BIO_LIB);
        goto err;
    }
    btmp = NULL;

    return 1;

 err:
    if (btmp)
        BIO_free(btmp);
    return 0;

}

static int pkcs7_encode_rinfo(PKCS7_RECIP_INFO *ri,
                              unsigned char *key, int keylen)
{
    EVP_PKEY_CTX *pctx = NULL;
    EVP_PKEY *pkey = NULL;
    unsigned char *ek = NULL;
    int ret = 0;
    size_t eklen;

    pkey = X509_get_pubkey(ri->cert);

    if (!pkey)
        return 0;

    pctx = EVP_PKEY_CTX_new(pkey, NULL);
    if (!pctx)
        return 0;

    if (EVP_PKEY_encrypt_init(pctx) <= 0)
        goto err;

    if (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_ENCRYPT,
                          EVP_PKEY_CTRL_PKCS7_ENCRYPT, 0, ri) <= 0) {
        PKCS7err(PKCS7_F_PKCS7_ENCODE_RINFO, PKCS7_R_CTRL_ERROR);
        goto err;
    }

    if (EVP_PKEY_encrypt(pctx, NULL, &eklen, key, keylen) <= 0)
        goto err;

    ek = OPENSSL_malloc(eklen);

    if (ek == NULL) {
        PKCS7err(PKCS7_F_PKCS7_ENCODE_RINFO, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    if (EVP_PKEY_encrypt(pctx, ek, &eklen, key, keylen) <= 0)
        goto err;

    ASN1_STRING_set0(ri->enc_key, ek, eklen);
    ek = NULL;

    ret = 1;

 err:
    if (pkey)
        EVP_PKEY_free(pkey);
    if (pctx)
        EVP_PKEY_CTX_free(pctx);
    if (ek)
        OPENSSL_free(ek);
    return ret;

}

static int pkcs7_decrypt_rinfo(unsigned char **pek, int *peklen,
                               PKCS7_RECIP_INFO *ri, EVP_PKEY *pkey)
{
    EVP_PKEY_CTX *pctx = NULL;
    unsigned char *ek = NULL;
    size_t eklen;

    int ret = -1;

    pctx = EVP_PKEY_CTX_new(pkey, NULL);
    if (!pctx)
        return -1;

    if (EVP_PKEY_decrypt_init(pctx) <= 0)
        goto err;

    if (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_DECRYPT,
                          EVP_PKEY_CTRL_PKCS7_DECRYPT, 0, ri) <= 0) {
        PKCS7err(PKCS7_F_PKCS7_DECRYPT_RINFO, PKCS7_R_CTRL_ERROR);
        goto err;
    }

    if (EVP_PKEY_decrypt(pctx, NULL, &eklen,
                         ri->enc_key->data, ri->enc_key->length) <= 0)
        goto err;

    ek = OPENSSL_malloc(eklen);

    if (ek == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DECRYPT_RINFO, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    if (EVP_PKEY_decrypt(pctx, ek, &eklen,
                         ri->enc_key->data, ri->enc_key->length) <= 0) {
        ret = 0;
        PKCS7err(PKCS7_F_PKCS7_DECRYPT_RINFO, ERR_R_EVP_LIB);
        goto err;
    }

    ret = 1;

    if (*pek) {
        OPENSSL_cleanse(*pek, *peklen);
        OPENSSL_free(*pek);
    }

    *pek = ek;
    *peklen = eklen;

 err:
    if (pctx)
        EVP_PKEY_CTX_free(pctx);
    if (!ret && ek)
        OPENSSL_free(ek);

    return ret;
}

BIO *PKCS7_dataInit(PKCS7 *p7, BIO *bio)
{
    int i;
    BIO *out = NULL, *btmp = NULL;
    X509_ALGOR *xa = NULL;
    const EVP_CIPHER *evp_cipher = NULL;
    STACK_OF(X509_ALGOR) *md_sk = NULL;
    STACK_OF(PKCS7_RECIP_INFO) *rsk = NULL;
    X509_ALGOR *xalg = NULL;
    PKCS7_RECIP_INFO *ri = NULL;
    ASN1_OCTET_STRING *os = NULL;

    if (p7 == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAINIT, PKCS7_R_INVALID_NULL_POINTER);
        return NULL;
    }
    /*
     * The content field in the PKCS7 ContentInfo is optional, but that really
     * only applies to inner content (precisely, detached signatures).
     *
     * When reading content, missing outer content is therefore treated as an
     * error.
     *
     * When creating content, PKCS7_content_new() must be called before
     * calling this method, so a NULL p7->d is always an error.
     */
    if (p7->d.ptr == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAINIT, PKCS7_R_NO_CONTENT);
        return NULL;
    }

    i = OBJ_obj2nid(p7->type);
    p7->state = PKCS7_S_HEADER;

    switch (i) {
    case NID_pkcs7_signed:
        md_sk = p7->d.sign->md_algs;
        os = PKCS7_get_octet_string(p7->d.sign->contents);
        break;
    case NID_pkcs7_signedAndEnveloped:
        rsk = p7->d.signed_and_enveloped->recipientinfo;
        md_sk = p7->d.signed_and_enveloped->md_algs;
        xalg = p7->d.signed_and_enveloped->enc_data->algorithm;
        evp_cipher = p7->d.signed_and_enveloped->enc_data->cipher;
        if (evp_cipher == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATAINIT, PKCS7_R_CIPHER_NOT_INITIALIZED);
            goto err;
        }
        break;
    case NID_pkcs7_enveloped:
        rsk = p7->d.enveloped->recipientinfo;
        xalg = p7->d.enveloped->enc_data->algorithm;
        evp_cipher = p7->d.enveloped->enc_data->cipher;
        if (evp_cipher == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATAINIT, PKCS7_R_CIPHER_NOT_INITIALIZED);
            goto err;
        }
        break;
    case NID_pkcs7_digest:
        xa = p7->d.digest->md;
        os = PKCS7_get_octet_string(p7->d.digest->contents);
        break;
    case NID_pkcs7_data:
        break;
    default:
        PKCS7err(PKCS7_F_PKCS7_DATAINIT, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);
        goto err;
    }

    for (i = 0; i < sk_X509_ALGOR_num(md_sk); i++)
        if (!PKCS7_bio_add_digest(&out, sk_X509_ALGOR_value(md_sk, i)))
            goto err;

    if (xa && !PKCS7_bio_add_digest(&out, xa))
        goto err;

    if (evp_cipher != NULL) {
        unsigned char key[EVP_MAX_KEY_LENGTH];
        unsigned char iv[EVP_MAX_IV_LENGTH];
        int keylen, ivlen;
        EVP_CIPHER_CTX *ctx;

        if ((btmp = BIO_new(BIO_f_cipher())) == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATAINIT, ERR_R_BIO_LIB);
            goto err;
        }
        BIO_get_cipher_ctx(btmp, &ctx);
        keylen = EVP_CIPHER_key_length(evp_cipher);
        ivlen = EVP_CIPHER_iv_length(evp_cipher);
        xalg->algorithm = OBJ_nid2obj(EVP_CIPHER_type(evp_cipher));
        if (ivlen > 0)
            if (RAND_pseudo_bytes(iv, ivlen) <= 0)
                goto err;
        if (EVP_CipherInit_ex(ctx, evp_cipher, NULL, NULL, NULL, 1) <= 0)
            goto err;
        if (EVP_CIPHER_CTX_rand_key(ctx, key) <= 0)
            goto err;
        if (EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, 1) <= 0)
            goto err;

        if (ivlen > 0) {
            if (xalg->parameter == NULL) {
                xalg->parameter = ASN1_TYPE_new();
                if (xalg->parameter == NULL)
                    goto err;
            }
            if (EVP_CIPHER_param_to_asn1(ctx, xalg->parameter) < 0)
                goto err;
        }

        /* Lets do the pub key stuff :-) */
        for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rsk); i++) {
            ri = sk_PKCS7_RECIP_INFO_value(rsk, i);
            if (pkcs7_encode_rinfo(ri, key, keylen) <= 0)
                goto err;
        }
        OPENSSL_cleanse(key, keylen);

        if (out == NULL)
            out = btmp;
        else
            BIO_push(out, btmp);
        btmp = NULL;
    }

    if (bio == NULL) {
        if (PKCS7_is_detached(p7))
            bio = BIO_new(BIO_s_null());
        else if (os && os->length > 0)
            bio = BIO_new_mem_buf(os->data, os->length);
        if (bio == NULL) {
            bio = BIO_new(BIO_s_mem());
            if (bio == NULL)
                goto err;
            BIO_set_mem_eof_return(bio, 0);
        }
    }
    if (out)
        BIO_push(out, bio);
    else
        out = bio;
    bio = NULL;
    if (0) {
 err:
        if (out != NULL)
            BIO_free_all(out);
        if (btmp != NULL)
            BIO_free_all(btmp);
        out = NULL;
    }
    return (out);
}

static int pkcs7_cmp_ri(PKCS7_RECIP_INFO *ri, X509 *pcert)
{
    int ret;
    ret = X509_NAME_cmp(ri->issuer_and_serial->issuer,
                        pcert->cert_info->issuer);
    if (ret)
        return ret;
    return M_ASN1_INTEGER_cmp(pcert->cert_info->serialNumber,
                              ri->issuer_and_serial->serial);
}

/* int */
BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert)
{
    int i, j;
    BIO *out = NULL, *btmp = NULL, *etmp = NULL, *bio = NULL;
    X509_ALGOR *xa;
    ASN1_OCTET_STRING *data_body = NULL;
    const EVP_MD *evp_md;
    const EVP_CIPHER *evp_cipher = NULL;
    EVP_CIPHER_CTX *evp_ctx = NULL;
    X509_ALGOR *enc_alg = NULL;
    STACK_OF(X509_ALGOR) *md_sk = NULL;
    STACK_OF(PKCS7_RECIP_INFO) *rsk = NULL;
    PKCS7_RECIP_INFO *ri = NULL;
    unsigned char *ek = NULL, *tkey = NULL;
    int eklen = 0, tkeylen = 0;

    if (p7 == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATADECODE, PKCS7_R_INVALID_NULL_POINTER);
        return NULL;
    }

    if (p7->d.ptr == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATADECODE, PKCS7_R_NO_CONTENT);
        return NULL;
    }

    i = OBJ_obj2nid(p7->type);
    p7->state = PKCS7_S_HEADER;

    switch (i) {
    case NID_pkcs7_signed:
        data_body = PKCS7_get_octet_string(p7->d.sign->contents);
        if (!PKCS7_is_detached(p7) && data_body == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATADECODE,
                     PKCS7_R_INVALID_SIGNED_DATA_TYPE);
            goto err;
        }
        md_sk = p7->d.sign->md_algs;
        break;
    case NID_pkcs7_signedAndEnveloped:
        rsk = p7->d.signed_and_enveloped->recipientinfo;
        md_sk = p7->d.signed_and_enveloped->md_algs;
        data_body = p7->d.signed_and_enveloped->enc_data->enc_data;
        enc_alg = p7->d.signed_and_enveloped->enc_data->algorithm;
        evp_cipher = EVP_get_cipherbyobj(enc_alg->algorithm);
        if (evp_cipher == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATADECODE,
                     PKCS7_R_UNSUPPORTED_CIPHER_TYPE);
            goto err;
        }
        break;
    case NID_pkcs7_enveloped:
        rsk = p7->d.enveloped->recipientinfo;
        enc_alg = p7->d.enveloped->enc_data->algorithm;
        data_body = p7->d.enveloped->enc_data->enc_data;
        evp_cipher = EVP_get_cipherbyobj(enc_alg->algorithm);
        if (evp_cipher == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATADECODE,
                     PKCS7_R_UNSUPPORTED_CIPHER_TYPE);
            goto err;
        }
        break;
    default:
        PKCS7err(PKCS7_F_PKCS7_DATADECODE, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);
        goto err;
    }

    /* We will be checking the signature */
    if (md_sk != NULL) {
        for (i = 0; i < sk_X509_ALGOR_num(md_sk); i++) {
            xa = sk_X509_ALGOR_value(md_sk, i);
            if ((btmp = BIO_new(BIO_f_md())) == NULL) {
                PKCS7err(PKCS7_F_PKCS7_DATADECODE, ERR_R_BIO_LIB);
                goto err;
            }

            j = OBJ_obj2nid(xa->algorithm);
            evp_md = EVP_get_digestbynid(j);
            if (evp_md == NULL) {
                PKCS7err(PKCS7_F_PKCS7_DATADECODE,
                         PKCS7_R_UNKNOWN_DIGEST_TYPE);
                goto err;
            }

            BIO_set_md(btmp, evp_md);
            if (out == NULL)
                out = btmp;
            else
                BIO_push(out, btmp);
            btmp = NULL;
        }
    }

    if (evp_cipher != NULL) {
#if 0
        unsigned char key[EVP_MAX_KEY_LENGTH];
        unsigned char iv[EVP_MAX_IV_LENGTH];
        unsigned char *p;
        int keylen, ivlen;
        int max;
        X509_OBJECT ret;
#endif

        if ((etmp = BIO_new(BIO_f_cipher())) == NULL) {
            PKCS7err(PKCS7_F_PKCS7_DATADECODE, ERR_R_BIO_LIB);
            goto err;
        }

        /*
         * It was encrypted, we need to decrypt the secret key with the
         * private key
         */

        /*
         * Find the recipientInfo which matches the passed certificate (if
         * any)
         */

        if (pcert) {
            for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rsk); i++) {
                ri = sk_PKCS7_RECIP_INFO_value(rsk, i);
                if (!pkcs7_cmp_ri(ri, pcert))
                    break;
                ri = NULL;
            }
            if (ri == NULL) {
                PKCS7err(PKCS7_F_PKCS7_DATADECODE,
                         PKCS7_R_NO_RECIPIENT_MATCHES_CERTIFICATE);
                goto err;
            }
        }

        /* If we haven't got a certificate try each ri in turn */
        if (pcert == NULL) {
            /*
             * Always attempt to decrypt all rinfo even after sucess as a
             * defence against MMA timing attacks.
             */
            for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rsk); i++) {
                ri = sk_PKCS7_RECIP_INFO_value(rsk, i);

                if (pkcs7_decrypt_rinfo(&ek, &eklen, ri, pkey) < 0)
                    goto err;
                ERR_clear_error();
            }
        } else {
            /* Only exit on fatal errors, not decrypt failure */
            if (pkcs7_decrypt_rinfo(&ek, &eklen, ri, pkey) < 0)
                goto err;
            ERR_clear_error();
        }

        evp_ctx = NULL;
        BIO_get_cipher_ctx(etmp, &evp_ctx);
        if (EVP_CipherInit_ex(evp_ctx, evp_cipher, NULL, NULL, NULL, 0) <= 0)
            goto err;
        if (EVP_CIPHER_asn1_to_param(evp_ctx, enc_alg->parameter) < 0)
            goto err;
        /* Generate random key as MMA defence */
        tkeylen = EVP_CIPHER_CTX_key_length(evp_ctx);
        tkey = OPENSSL_malloc(tkeylen);
        if (!tkey)
            goto err;
        if (EVP_CIPHER_CTX_rand_key(evp_ctx, tkey) <= 0)
            goto err;
        if (ek == NULL) {
            ek = tkey;
            eklen = tkeylen;
            tkey = NULL;
        }

        if (eklen != EVP_CIPHER_CTX_key_length(evp_ctx)) {
            /*
             * Some S/MIME clients don't use the same key and effective key
             * length. The key length is determined by the size of the
             * decrypted RSA key.
             */
            if (!EVP_CIPHER_CTX_set_key_length(evp_ctx, eklen)) {
                /* Use random key as MMA defence */
                OPENSSL_cleanse(ek, eklen);
                OPENSSL_free(ek);
                ek = tkey;
                eklen = tkeylen;
                tkey = NULL;
            }
        }
        /* Clear errors so we don't leak information useful in MMA */
        ERR_clear_error();
        if (EVP_CipherInit_ex(evp_ctx, NULL, NULL, ek, NULL, 0) <= 0)
            goto err;

        if (ek) {
            OPENSSL_cleanse(ek, eklen);
            OPENSSL_free(ek);
            ek = NULL;
        }
        if (tkey) {
            OPENSSL_cleanse(tkey, tkeylen);
            OPENSSL_free(tkey);
            tkey = NULL;
        }

        if (out == NULL)
            out = etmp;
        else
            BIO_push(out, etmp);
        etmp = NULL;
    }
#if 1
    if (PKCS7_is_detached(p7) || (in_bio != NULL)) {
        bio = in_bio;
    } else {
# if 0
        bio = BIO_new(BIO_s_mem());
        /*
         * We need to set this so that when we have read all the data, the
         * encrypt BIO, if present, will read EOF and encode the last few
         * bytes
         */
        BIO_set_mem_eof_return(bio, 0);

        if (data_body->length > 0)
            BIO_write(bio, (char *)data_body->data, data_body->length);
# else
        if (data_body->length > 0)
            bio = BIO_new_mem_buf(data_body->data, data_body->length);
        else {
            bio = BIO_new(BIO_s_mem());
            BIO_set_mem_eof_return(bio, 0);
        }
        if (bio == NULL)
            goto err;
# endif
    }
    BIO_push(out, bio);
    bio = NULL;
#endif
    if (0) {
 err:
        if (ek) {
            OPENSSL_cleanse(ek, eklen);
            OPENSSL_free(ek);
        }
        if (tkey) {
            OPENSSL_cleanse(tkey, tkeylen);
            OPENSSL_free(tkey);
        }
        if (out != NULL)
            BIO_free_all(out);
        if (btmp != NULL)
            BIO_free_all(btmp);
        if (etmp != NULL)
            BIO_free_all(etmp);
        if (bio != NULL)
            BIO_free_all(bio);
        out = NULL;
    }
    return (out);
}

static BIO *PKCS7_find_digest(EVP_MD_CTX **pmd, BIO *bio, int nid)
{
    for (;;) {
        bio = BIO_find_type(bio, BIO_TYPE_MD);
        if (bio == NULL) {
            PKCS7err(PKCS7_F_PKCS7_FIND_DIGEST,
                     PKCS7_R_UNABLE_TO_FIND_MESSAGE_DIGEST);
            return NULL;
        }
        BIO_get_md_ctx(bio, pmd);
        if (*pmd == NULL) {
            PKCS7err(PKCS7_F_PKCS7_FIND_DIGEST, ERR_R_INTERNAL_ERROR);
            return NULL;
        }
        if (EVP_MD_CTX_type(*pmd) == nid)
            return bio;
        bio = BIO_next(bio);
    }
    return NULL;
}

static int do_pkcs7_signed_attrib(PKCS7_SIGNER_INFO *si, EVP_MD_CTX *mctx)
{
    unsigned char md_data[EVP_MAX_MD_SIZE];
    unsigned int md_len;

    /* Add signing time if not already present */
    if (!PKCS7_get_signed_attribute(si, NID_pkcs9_signingTime)) {
        if (!PKCS7_add0_attrib_signing_time(si, NULL)) {
            PKCS7err(PKCS7_F_DO_PKCS7_SIGNED_ATTRIB, ERR_R_MALLOC_FAILURE);
            return 0;
        }
    }

    /* Add digest */
    if (!EVP_DigestFinal_ex(mctx, md_data, &md_len)) {
        PKCS7err(PKCS7_F_DO_PKCS7_SIGNED_ATTRIB, ERR_R_EVP_LIB);
        return 0;
    }
    if (!PKCS7_add1_attrib_digest(si, md_data, md_len)) {
        PKCS7err(PKCS7_F_DO_PKCS7_SIGNED_ATTRIB, ERR_R_MALLOC_FAILURE);
        return 0;
    }

    /* Now sign the attributes */
    if (!PKCS7_SIGNER_INFO_sign(si))
        return 0;

    return 1;
}

int PKCS7_dataFinal(PKCS7 *p7, BIO *bio)
{
    int ret = 0;
    int i, j;
    BIO *btmp;
    PKCS7_SIGNER_INFO *si;
    EVP_MD_CTX *mdc, ctx_tmp;
    STACK_OF(X509_ATTRIBUTE) *sk;
    STACK_OF(PKCS7_SIGNER_INFO) *si_sk = NULL;
    ASN1_OCTET_STRING *os = NULL;

    if (p7 == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAFINAL, PKCS7_R_INVALID_NULL_POINTER);
        return 0;
    }

    if (p7->d.ptr == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAFINAL, PKCS7_R_NO_CONTENT);
        return 0;
    }

    EVP_MD_CTX_init(&ctx_tmp);
    i = OBJ_obj2nid(p7->type);
    p7->state = PKCS7_S_HEADER;

    switch (i) {
    case NID_pkcs7_data:
        os = p7->d.data;
        break;
    case NID_pkcs7_signedAndEnveloped:
        /* XXXXXXXXXXXXXXXX */
        si_sk = p7->d.signed_and_enveloped->signer_info;
        os = p7->d.signed_and_enveloped->enc_data->enc_data;
        if (!os) {
            os = M_ASN1_OCTET_STRING_new();
            if (!os) {
                PKCS7err(PKCS7_F_PKCS7_DATAFINAL, ERR_R_MALLOC_FAILURE);
                goto err;
            }
            p7->d.signed_and_enveloped->enc_data->enc_data = os;
        }
        break;
    case NID_pkcs7_enveloped:
        /* XXXXXXXXXXXXXXXX */
        os = p7->d.enveloped->enc_data->enc_data;
        if (!os) {
            os = M_ASN1_OCTET_STRING_new();
            if (!os) {
                PKCS7err(PKCS7_F_PKCS7_DATAFINAL, ERR_R_MALLOC_FAILURE);
                goto err;
            }
            p7->d.enveloped->enc_data->enc_data = os;
        }
        break;
    case NID_pkcs7_signed:
        si_sk = p7->d.sign->signer_info;
        os = PKCS7_get_octet_string(p7->d.sign->contents);
        /* If detached data then the content is excluded */
        if (PKCS7_type_is_data(p7->d.sign->contents) && p7->detached) {
            M_ASN1_OCTET_STRING_free(os);
            os = NULL;
            p7->d.sign->contents->d.data = NULL;
        }
        break;

    case NID_pkcs7_digest:
        os = PKCS7_get_octet_string(p7->d.digest->contents);
        /* If detached data then the content is excluded */
        if (PKCS7_type_is_data(p7->d.digest->contents) && p7->detached) {
            M_ASN1_OCTET_STRING_free(os);
            os = NULL;
            p7->d.digest->contents->d.data = NULL;
        }
        break;

    default:
        PKCS7err(PKCS7_F_PKCS7_DATAFINAL, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);
        goto err;
    }

    if (si_sk != NULL) {
        for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(si_sk); i++) {
            si = sk_PKCS7_SIGNER_INFO_value(si_sk, i);
            if (si->pkey == NULL)
                continue;

            j = OBJ_obj2nid(si->digest_alg->algorithm);

            btmp = bio;

            btmp = PKCS7_find_digest(&mdc, btmp, j);

            if (btmp == NULL)
                goto err;

            /*
             * We now have the EVP_MD_CTX, lets do the signing.
             */
            if (!EVP_MD_CTX_copy_ex(&ctx_tmp, mdc))
                goto err;

            sk = si->auth_attr;

            /*
             * If there are attributes, we add the digest attribute and only
             * sign the attributes
             */
            if (sk_X509_ATTRIBUTE_num(sk) > 0) {
                if (!do_pkcs7_signed_attrib(si, &ctx_tmp))
                    goto err;
            } else {
                unsigned char *abuf = NULL;
                unsigned int abuflen;
                abuflen = EVP_PKEY_size(si->pkey);
                abuf = OPENSSL_malloc(abuflen);
                if (!abuf)
                    goto err;

                if (!EVP_SignFinal(&ctx_tmp, abuf, &abuflen, si->pkey)) {
                    PKCS7err(PKCS7_F_PKCS7_DATAFINAL, ERR_R_EVP_LIB);
                    goto err;
                }
                ASN1_STRING_set0(si->enc_digest, abuf, abuflen);
            }
        }
    } else if (i == NID_pkcs7_digest) {
        unsigned char md_data[EVP_MAX_MD_SIZE];
        unsigned int md_len;
        if (!PKCS7_find_digest(&mdc, bio,
                               OBJ_obj2nid(p7->d.digest->md->algorithm)))
            goto err;
        if (!EVP_DigestFinal_ex(mdc, md_data, &md_len))
            goto err;
        M_ASN1_OCTET_STRING_set(p7->d.digest->digest, md_data, md_len);
    }

    if (!PKCS7_is_detached(p7)) {
        /*
         * NOTE(emilia): I think we only reach os == NULL here because detached
         * digested data support is broken.
         */
        if (os == NULL)
            goto err;
        if (!(os->flags & ASN1_STRING_FLAG_NDEF)) {
            char *cont;
            long contlen;
            btmp = BIO_find_type(bio, BIO_TYPE_MEM);
            if (btmp == NULL) {
                PKCS7err(PKCS7_F_PKCS7_DATAFINAL, PKCS7_R_UNABLE_TO_FIND_MEM_BIO);
                goto err;
            }
            contlen = BIO_get_mem_data(btmp, &cont);
            /*
             * Mark the BIO read only then we can use its copy of the data
             * instead of making an extra copy.
             */
            BIO_set_flags(btmp, BIO_FLAGS_MEM_RDONLY);
            BIO_set_mem_eof_return(btmp, 0);
            ASN1_STRING_set0(os, (unsigned char *)cont, contlen);
        }
    }
    ret = 1;
 err:
    EVP_MD_CTX_cleanup(&ctx_tmp);
    return (ret);
}

int PKCS7_SIGNER_INFO_sign(PKCS7_SIGNER_INFO *si)
{
    EVP_MD_CTX mctx;
    EVP_PKEY_CTX *pctx;
    unsigned char *abuf = NULL;
    int alen;
    size_t siglen;
    const EVP_MD *md = NULL;

    md = EVP_get_digestbyobj(si->digest_alg->algorithm);
    if (md == NULL)
        return 0;

    EVP_MD_CTX_init(&mctx);
    if (EVP_DigestSignInit(&mctx, &pctx, md, NULL, si->pkey) <= 0)
        goto err;

    if (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_SIGN,
                          EVP_PKEY_CTRL_PKCS7_SIGN, 0, si) <= 0) {
        PKCS7err(PKCS7_F_PKCS7_SIGNER_INFO_SIGN, PKCS7_R_CTRL_ERROR);
        goto err;
    }

    alen = ASN1_item_i2d((ASN1_VALUE *)si->auth_attr, &abuf,
                         ASN1_ITEM_rptr(PKCS7_ATTR_SIGN));
    if (!abuf)
        goto err;
    if (EVP_DigestSignUpdate(&mctx, abuf, alen) <= 0)
        goto err;
    OPENSSL_free(abuf);
    abuf = NULL;
    if (EVP_DigestSignFinal(&mctx, NULL, &siglen) <= 0)
        goto err;
    abuf = OPENSSL_malloc(siglen);
    if (!abuf)
        goto err;
    if (EVP_DigestSignFinal(&mctx, abuf, &siglen) <= 0)
        goto err;

    if (EVP_PKEY_CTX_ctrl(pctx, -1, EVP_PKEY_OP_SIGN,
                          EVP_PKEY_CTRL_PKCS7_SIGN, 1, si) <= 0) {
        PKCS7err(PKCS7_F_PKCS7_SIGNER_INFO_SIGN, PKCS7_R_CTRL_ERROR);
        goto err;
    }

    EVP_MD_CTX_cleanup(&mctx);

    ASN1_STRING_set0(si->enc_digest, abuf, siglen);

    return 1;

 err:
    if (abuf)
        OPENSSL_free(abuf);
    EVP_MD_CTX_cleanup(&mctx);
    return 0;

}

int PKCS7_dataVerify(X509_STORE *cert_store, X509_STORE_CTX *ctx, BIO *bio,
                     PKCS7 *p7, PKCS7_SIGNER_INFO *si)
{
    PKCS7_ISSUER_AND_SERIAL *ias;
    int ret = 0, i;
    STACK_OF(X509) *cert;
    X509 *x509;

    if (p7 == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAVERIFY, PKCS7_R_INVALID_NULL_POINTER);
        return 0;
    }

    if (p7->d.ptr == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAVERIFY, PKCS7_R_NO_CONTENT);
        return 0;
    }

    if (PKCS7_type_is_signed(p7)) {
        cert = p7->d.sign->cert;
    } else if (PKCS7_type_is_signedAndEnveloped(p7)) {
        cert = p7->d.signed_and_enveloped->cert;
    } else {
        PKCS7err(PKCS7_F_PKCS7_DATAVERIFY, PKCS7_R_WRONG_PKCS7_TYPE);
        goto err;
    }
    /* XXXXXXXXXXXXXXXXXXXXXXX */
    ias = si->issuer_and_serial;

    x509 = X509_find_by_issuer_and_serial(cert, ias->issuer, ias->serial);

    /* were we able to find the cert in passed to us */
    if (x509 == NULL) {
        PKCS7err(PKCS7_F_PKCS7_DATAVERIFY,
                 PKCS7_R_UNABLE_TO_FIND_CERTIFICATE);
        goto err;
    }

    /* Lets verify */
    if (!X509_STORE_CTX_init(ctx, cert_store, x509, cert)) {
        PKCS7err(PKCS7_F_PKCS7_DATAVERIFY, ERR_R_X509_LIB);
        goto err;
    }
    X509_STORE_CTX_set_purpose(ctx, X509_PURPOSE_SMIME_SIGN);
    i = X509_verify_cert(ctx);
    if (i <= 0) {
        PKCS7err(PKCS7_F_PKCS7_DATAVERIFY, ERR_R_X509_LIB);
        X509_STORE_CTX_cleanup(ctx);
        goto err;
    }
    X509_STORE_CTX_cleanup(ctx);

    return PKCS7_signatureVerify(bio, p7, si, x509);
 err:
    return ret;
}

int PKCS7_signatureVerify(BIO *bio, PKCS7 *p7, PKCS7_SIGNER_INFO *si,
                          X509 *x509)
{
    ASN1_OCTET_STRING *os;
    EVP_MD_CTX mdc_tmp, *mdc;
    int ret = 0, i;
    int md_type;
    STACK_OF(X509_ATTRIBUTE) *sk;
    BIO *btmp;
    EVP_PKEY *pkey;

    EVP_MD_CTX_init(&mdc_tmp);

    if (!PKCS7_type_is_signed(p7) && !PKCS7_type_is_signedAndEnveloped(p7)) {
        PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY, PKCS7_R_WRONG_PKCS7_TYPE);
        goto err;
    }

    md_type = OBJ_obj2nid(si->digest_alg->algorithm);

    btmp = bio;
    for (;;) {
        if ((btmp == NULL) ||
            ((btmp = BIO_find_type(btmp, BIO_TYPE_MD)) == NULL)) {
            PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY,
                     PKCS7_R_UNABLE_TO_FIND_MESSAGE_DIGEST);
            goto err;
        }
        BIO_get_md_ctx(btmp, &mdc);
        if (mdc == NULL) {
            PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY, ERR_R_INTERNAL_ERROR);
            goto err;
        }
        if (EVP_MD_CTX_type(mdc) == md_type)
            break;
        /*
         * Workaround for some broken clients that put the signature OID
         * instead of the digest OID in digest_alg->algorithm
         */
        if (EVP_MD_pkey_type(EVP_MD_CTX_md(mdc)) == md_type)
            break;
        btmp = BIO_next(btmp);
    }

    /*
     * mdc is the digest ctx that we want, unless there are attributes, in
     * which case the digest is the signed attributes
     */
    if (!EVP_MD_CTX_copy_ex(&mdc_tmp, mdc))
        goto err;

    sk = si->auth_attr;
    if ((sk != NULL) && (sk_X509_ATTRIBUTE_num(sk) != 0)) {
        unsigned char md_dat[EVP_MAX_MD_SIZE], *abuf = NULL;
        unsigned int md_len;
        int alen;
        ASN1_OCTET_STRING *message_digest;

        if (!EVP_DigestFinal_ex(&mdc_tmp, md_dat, &md_len))
            goto err;
        message_digest = PKCS7_digest_from_attributes(sk);
        if (!message_digest) {
            PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY,
                     PKCS7_R_UNABLE_TO_FIND_MESSAGE_DIGEST);
            goto err;
        }
        if ((message_digest->length != (int)md_len) ||
            (memcmp(message_digest->data, md_dat, md_len))) {
#if 0
            {
                int ii;
                for (ii = 0; ii < message_digest->length; ii++)
                    printf("%02X", message_digest->data[ii]);
                printf(" sent\n");
                for (ii = 0; ii < md_len; ii++)
                    printf("%02X", md_dat[ii]);
                printf(" calc\n");
            }
#endif
            PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY, PKCS7_R_DIGEST_FAILURE);
            ret = -1;
            goto err;
        }

        if (!EVP_VerifyInit_ex(&mdc_tmp, EVP_get_digestbynid(md_type), NULL))
            goto err;

        alen = ASN1_item_i2d((ASN1_VALUE *)sk, &abuf,
                             ASN1_ITEM_rptr(PKCS7_ATTR_VERIFY));
        if (alen <= 0) {
            PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY, ERR_R_ASN1_LIB);
            ret = -1;
            goto err;
        }
        if (!EVP_VerifyUpdate(&mdc_tmp, abuf, alen))
            goto err;

        OPENSSL_free(abuf);
    }

    os = si->enc_digest;
    pkey = X509_get_pubkey(x509);
    if (!pkey) {
        ret = -1;
        goto err;
    }

    i = EVP_VerifyFinal(&mdc_tmp, os->data, os->length, pkey);
    EVP_PKEY_free(pkey);
    if (i <= 0) {
        PKCS7err(PKCS7_F_PKCS7_SIGNATUREVERIFY, PKCS7_R_SIGNATURE_FAILURE);
        ret = -1;
        goto err;
    } else
        ret = 1;
 err:
    EVP_MD_CTX_cleanup(&mdc_tmp);
    return (ret);
}

PKCS7_ISSUER_AND_SERIAL *PKCS7_get_issuer_and_serial(PKCS7 *p7, int idx)
{
    STACK_OF(PKCS7_RECIP_INFO) *rsk;
    PKCS7_RECIP_INFO *ri;
    int i;

    i = OBJ_obj2nid(p7->type);
    if (i != NID_pkcs7_signedAndEnveloped)
        return NULL;
    if (p7->d.signed_and_enveloped == NULL)
        return NULL;
    rsk = p7->d.signed_and_enveloped->recipientinfo;
    if (rsk == NULL)
        return NULL;
    ri = sk_PKCS7_RECIP_INFO_value(rsk, 0);
    if (sk_PKCS7_RECIP_INFO_num(rsk) <= idx)
        return (NULL);
    ri = sk_PKCS7_RECIP_INFO_value(rsk, idx);
    return (ri->issuer_and_serial);
}

ASN1_TYPE *PKCS7_get_signed_attribute(PKCS7_SIGNER_INFO *si, int nid)
{
    return (get_attribute(si->auth_attr, nid));
}

ASN1_TYPE *PKCS7_get_attribute(PKCS7_SIGNER_INFO *si, int nid)
{
    return (get_attribute(si->unauth_attr, nid));
}

static ASN1_TYPE *get_attribute(STACK_OF(X509_ATTRIBUTE) *sk, int nid)
{
    int i;
    X509_ATTRIBUTE *xa;
    ASN1_OBJECT *o;

    o = OBJ_nid2obj(nid);
    if (!o || !sk)
        return (NULL);
    for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
        xa = sk_X509_ATTRIBUTE_value(sk, i);
        if (OBJ_cmp(xa->object, o) == 0) {
            if (!xa->single && sk_ASN1_TYPE_num(xa->value.set))
                return (sk_ASN1_TYPE_value(xa->value.set, 0));
            else
                return (NULL);
        }
    }
    return (NULL);
}

ASN1_OCTET_STRING *PKCS7_digest_from_attributes(STACK_OF(X509_ATTRIBUTE) *sk)
{
    ASN1_TYPE *astype;
    if (!(astype = get_attribute(sk, NID_pkcs9_messageDigest)))
        return NULL;
    return astype->value.octet_string;
}

int PKCS7_set_signed_attributes(PKCS7_SIGNER_INFO *p7si,
                                STACK_OF(X509_ATTRIBUTE) *sk)
{
    int i;

    if (p7si->auth_attr != NULL)
        sk_X509_ATTRIBUTE_pop_free(p7si->auth_attr, X509_ATTRIBUTE_free);
    p7si->auth_attr = sk_X509_ATTRIBUTE_dup(sk);
    if (p7si->auth_attr == NULL)
        return 0;
    for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
        if ((sk_X509_ATTRIBUTE_set(p7si->auth_attr, i,
                                   X509_ATTRIBUTE_dup(sk_X509_ATTRIBUTE_value
                                                      (sk, i))))
            == NULL)
            return (0);
    }
    return (1);
}

int PKCS7_set_attributes(PKCS7_SIGNER_INFO *p7si,
                         STACK_OF(X509_ATTRIBUTE) *sk)
{
    int i;

    if (p7si->unauth_attr != NULL)
        sk_X509_ATTRIBUTE_pop_free(p7si->unauth_attr, X509_ATTRIBUTE_free);
    p7si->unauth_attr = sk_X509_ATTRIBUTE_dup(sk);
    if (p7si->unauth_attr == NULL)
        return 0;
    for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
        if ((sk_X509_ATTRIBUTE_set(p7si->unauth_attr, i,
                                   X509_ATTRIBUTE_dup(sk_X509_ATTRIBUTE_value
                                                      (sk, i))))
            == NULL)
            return (0);
    }
    return (1);
}

int PKCS7_add_signed_attribute(PKCS7_SIGNER_INFO *p7si, int nid, int atrtype,
                               void *value)
{
    return (add_attribute(&(p7si->auth_attr), nid, atrtype, value));
}

int PKCS7_add_attribute(PKCS7_SIGNER_INFO *p7si, int nid, int atrtype,
                        void *value)
{
    return (add_attribute(&(p7si->unauth_attr), nid, atrtype, value));
}

static int add_attribute(STACK_OF(X509_ATTRIBUTE) **sk, int nid, int atrtype,
                         void *value)
{
    X509_ATTRIBUTE *attr = NULL;

    if (*sk == NULL) {
        *sk = sk_X509_ATTRIBUTE_new_null();
        if (*sk == NULL)
            return 0;
 new_attrib:
        if (!(attr = X509_ATTRIBUTE_create(nid, atrtype, value)))
            return 0;
        if (!sk_X509_ATTRIBUTE_push(*sk, attr)) {
            X509_ATTRIBUTE_free(attr);
            return 0;
        }
    } else {
        int i;

        for (i = 0; i < sk_X509_ATTRIBUTE_num(*sk); i++) {
            attr = sk_X509_ATTRIBUTE_value(*sk, i);
            if (OBJ_obj2nid(attr->object) == nid) {
                X509_ATTRIBUTE_free(attr);
                attr = X509_ATTRIBUTE_create(nid, atrtype, value);
                if (attr == NULL)
                    return 0;
                if (!sk_X509_ATTRIBUTE_set(*sk, i, attr)) {
                    X509_ATTRIBUTE_free(attr);
                    return 0;
                }
                goto end;
            }
        }
        goto new_attrib;
    }
 end:
    return (1);
}
