/* pk7_smime.c */
/*
 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 1999-2004 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).
 *
 */

/* Simple PKCS#7 processing functions */

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

static int pkcs7_copy_existing_digest(PKCS7 *p7, PKCS7_SIGNER_INFO *si);

PKCS7 *PKCS7_sign(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs,
                  BIO *data, int flags)
{
    PKCS7 *p7;
    int i;

    if (!(p7 = PKCS7_new())) {
        PKCS7err(PKCS7_F_PKCS7_SIGN, ERR_R_MALLOC_FAILURE);
        return NULL;
    }

    if (!PKCS7_set_type(p7, NID_pkcs7_signed))
        goto err;

    if (!PKCS7_content_new(p7, NID_pkcs7_data))
        goto err;

    if (pkey && !PKCS7_sign_add_signer(p7, signcert, pkey, NULL, flags)) {
        PKCS7err(PKCS7_F_PKCS7_SIGN, PKCS7_R_PKCS7_ADD_SIGNER_ERROR);
        goto err;
    }

    if (!(flags & PKCS7_NOCERTS)) {
        for (i = 0; i < sk_X509_num(certs); i++) {
            if (!PKCS7_add_certificate(p7, sk_X509_value(certs, i)))
                goto err;
        }
    }

    if (flags & PKCS7_DETACHED)
        PKCS7_set_detached(p7, 1);

    if (flags & (PKCS7_STREAM | PKCS7_PARTIAL))
        return p7;

    if (PKCS7_final(p7, data, flags))
        return p7;

 err:
    PKCS7_free(p7);
    return NULL;
}

int PKCS7_final(PKCS7 *p7, BIO *data, int flags)
{
    BIO *p7bio;
    int ret = 0;
    if (!(p7bio = PKCS7_dataInit(p7, NULL))) {
        PKCS7err(PKCS7_F_PKCS7_FINAL, ERR_R_MALLOC_FAILURE);
        return 0;
    }

    SMIME_crlf_copy(data, p7bio, flags);

    (void)BIO_flush(p7bio);

    if (!PKCS7_dataFinal(p7, p7bio)) {
        PKCS7err(PKCS7_F_PKCS7_FINAL, PKCS7_R_PKCS7_DATASIGN);
        goto err;
    }

    ret = 1;

 err:
    BIO_free_all(p7bio);

    return ret;

}

/* Check to see if a cipher exists and if so add S/MIME capabilities */

static int add_cipher_smcap(STACK_OF(X509_ALGOR) *sk, int nid, int arg)
{
    if (EVP_get_cipherbynid(nid))
        return PKCS7_simple_smimecap(sk, nid, arg);
    return 1;
}

static int add_digest_smcap(STACK_OF(X509_ALGOR) *sk, int nid, int arg)
{
    if (EVP_get_digestbynid(nid))
        return PKCS7_simple_smimecap(sk, nid, arg);
    return 1;
}

PKCS7_SIGNER_INFO *PKCS7_sign_add_signer(PKCS7 *p7, X509 *signcert,
                                         EVP_PKEY *pkey, const EVP_MD *md,
                                         int flags)
{
    PKCS7_SIGNER_INFO *si = NULL;
    STACK_OF(X509_ALGOR) *smcap = NULL;
    if (!X509_check_private_key(signcert, pkey)) {
        PKCS7err(PKCS7_F_PKCS7_SIGN_ADD_SIGNER,
                 PKCS7_R_PRIVATE_KEY_DOES_NOT_MATCH_CERTIFICATE);
        return NULL;
    }

    if (!(si = PKCS7_add_signature(p7, signcert, pkey, md))) {
        PKCS7err(PKCS7_F_PKCS7_SIGN_ADD_SIGNER,
                 PKCS7_R_PKCS7_ADD_SIGNATURE_ERROR);
        return NULL;
    }

    if (!(flags & PKCS7_NOCERTS)) {
        if (!PKCS7_add_certificate(p7, signcert))
            goto err;
    }

    if (!(flags & PKCS7_NOATTR)) {
        if (!PKCS7_add_attrib_content_type(si, NULL))
            goto err;
        /* Add SMIMECapabilities */
        if (!(flags & PKCS7_NOSMIMECAP)) {
            if (!(smcap = sk_X509_ALGOR_new_null())) {
                PKCS7err(PKCS7_F_PKCS7_SIGN_ADD_SIGNER, ERR_R_MALLOC_FAILURE);
                goto err;
            }
            if (!add_cipher_smcap(smcap, NID_aes_256_cbc, -1)
                || !add_digest_smcap(smcap, NID_id_GostR3411_94, -1)
                || !add_cipher_smcap(smcap, NID_id_Gost28147_89, -1)
                || !add_cipher_smcap(smcap, NID_aes_192_cbc, -1)
                || !add_cipher_smcap(smcap, NID_aes_128_cbc, -1)
                || !add_cipher_smcap(smcap, NID_des_ede3_cbc, -1)
                || !add_cipher_smcap(smcap, NID_rc2_cbc, 128)
                || !add_cipher_smcap(smcap, NID_rc2_cbc, 64)
                || !add_cipher_smcap(smcap, NID_des_cbc, -1)
                || !add_cipher_smcap(smcap, NID_rc2_cbc, 40)
                || !PKCS7_add_attrib_smimecap(si, smcap))
                goto err;
            sk_X509_ALGOR_pop_free(smcap, X509_ALGOR_free);
            smcap = NULL;
        }
        if (flags & PKCS7_REUSE_DIGEST) {
            if (!pkcs7_copy_existing_digest(p7, si))
                goto err;
            if (!(flags & PKCS7_PARTIAL) && !PKCS7_SIGNER_INFO_sign(si))
                goto err;
        }
    }
    return si;
 err:
    sk_X509_ALGOR_pop_free(smcap, X509_ALGOR_free);
    return NULL;
}

/*
 * Search for a digest matching SignerInfo digest type and if found copy
 * across.
 */

static int pkcs7_copy_existing_digest(PKCS7 *p7, PKCS7_SIGNER_INFO *si)
{
    int i;
    STACK_OF(PKCS7_SIGNER_INFO) *sinfos;
    PKCS7_SIGNER_INFO *sitmp;
    ASN1_OCTET_STRING *osdig = NULL;
    sinfos = PKCS7_get_signer_info(p7);
    for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(sinfos); i++) {
        sitmp = sk_PKCS7_SIGNER_INFO_value(sinfos, i);
        if (si == sitmp)
            break;
        if (sk_X509_ATTRIBUTE_num(sitmp->auth_attr) <= 0)
            continue;
        if (!OBJ_cmp(si->digest_alg->algorithm, sitmp->digest_alg->algorithm)) {
            osdig = PKCS7_digest_from_attributes(sitmp->auth_attr);
            break;
        }

    }

    if (osdig)
        return PKCS7_add1_attrib_digest(si, osdig->data, osdig->length);

    PKCS7err(PKCS7_F_PKCS7_COPY_EXISTING_DIGEST,
             PKCS7_R_NO_MATCHING_DIGEST_TYPE_FOUND);
    return 0;
}

int PKCS7_verify(PKCS7 *p7, STACK_OF(X509) *certs, X509_STORE *store,
                 BIO *indata, BIO *out, int flags)
{
    STACK_OF(X509) *signers;
    X509 *signer;
    STACK_OF(PKCS7_SIGNER_INFO) *sinfos;
    PKCS7_SIGNER_INFO *si;
    X509_STORE_CTX cert_ctx;
    char buf[4096];
    int i, j = 0, k, ret = 0;
    BIO *p7bio;
    BIO *tmpin, *tmpout;

    if (!p7) {
        PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_INVALID_NULL_POINTER);
        return 0;
    }

    if (!PKCS7_type_is_signed(p7)) {
        PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_WRONG_CONTENT_TYPE);
        return 0;
    }

    /* Check for no data and no content: no data to verify signature */
    if (PKCS7_get_detached(p7) && !indata) {
        PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_NO_CONTENT);
        return 0;
    }

    /*
     * Very old Netscape illegally included empty content with
     * a detached signature. To not support that, enable the
     * following flag.
     */
#ifdef OPENSSL_DONT_SUPPORT_OLD_NETSCAPE
    /* Check for data and content: two sets of data */
    if (!PKCS7_get_detached(p7) && indata) {
        PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_CONTENT_AND_DATA_PRESENT);
        return 0;
    }
#endif

    sinfos = PKCS7_get_signer_info(p7);

    if (!sinfos || !sk_PKCS7_SIGNER_INFO_num(sinfos)) {
        PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_NO_SIGNATURES_ON_DATA);
        return 0;
    }

    signers = PKCS7_get0_signers(p7, certs, flags);

    if (!signers)
        return 0;

    /* Now verify the certificates */

    if (!(flags & PKCS7_NOVERIFY))
        for (k = 0; k < sk_X509_num(signers); k++) {
            signer = sk_X509_value(signers, k);
            if (!(flags & PKCS7_NOCHAIN)) {
                if (!X509_STORE_CTX_init(&cert_ctx, store, signer,
                                         p7->d.sign->cert)) {
                    PKCS7err(PKCS7_F_PKCS7_VERIFY, ERR_R_X509_LIB);
                    sk_X509_free(signers);
                    return 0;
                }
                X509_STORE_CTX_set_default(&cert_ctx, "smime_sign");
            } else if (!X509_STORE_CTX_init(&cert_ctx, store, signer, NULL)) {
                PKCS7err(PKCS7_F_PKCS7_VERIFY, ERR_R_X509_LIB);
                sk_X509_free(signers);
                return 0;
            }
            if (!(flags & PKCS7_NOCRL))
                X509_STORE_CTX_set0_crls(&cert_ctx, p7->d.sign->crl);
            i = X509_verify_cert(&cert_ctx);
            if (i <= 0)
                j = X509_STORE_CTX_get_error(&cert_ctx);
            X509_STORE_CTX_cleanup(&cert_ctx);
            if (i <= 0) {
                PKCS7err(PKCS7_F_PKCS7_VERIFY,
                         PKCS7_R_CERTIFICATE_VERIFY_ERROR);
                ERR_add_error_data(2, "Verify error:",
                                   X509_verify_cert_error_string(j));
                sk_X509_free(signers);
                return 0;
            }
            /* Check for revocation status here */
        }

    /*
     * Performance optimization: if the content is a memory BIO then store
     * its contents in a temporary read only memory BIO. This avoids
     * potentially large numbers of slow copies of data which will occur when
     * reading from a read write memory BIO when signatures are calculated.
     */

    if (indata && (BIO_method_type(indata) == BIO_TYPE_MEM)) {
        char *ptr;
        long len;
        len = BIO_get_mem_data(indata, &ptr);
        tmpin = BIO_new_mem_buf(ptr, len);
        if (tmpin == NULL) {
            PKCS7err(PKCS7_F_PKCS7_VERIFY, ERR_R_MALLOC_FAILURE);
            return 0;
        }
    } else
        tmpin = indata;

    if (!(p7bio = PKCS7_dataInit(p7, tmpin)))
        goto err;

    if (flags & PKCS7_TEXT) {
        if (!(tmpout = BIO_new(BIO_s_mem()))) {
            PKCS7err(PKCS7_F_PKCS7_VERIFY, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        BIO_set_mem_eof_return(tmpout, 0);
    } else
        tmpout = out;

    /* We now have to 'read' from p7bio to calculate digests etc. */
    for (;;) {
        i = BIO_read(p7bio, buf, sizeof(buf));
        if (i <= 0)
            break;
        if (tmpout)
            BIO_write(tmpout, buf, i);
    }

    if (flags & PKCS7_TEXT) {
        if (!SMIME_text(tmpout, out)) {
            PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_SMIME_TEXT_ERROR);
            BIO_free(tmpout);
            goto err;
        }
        BIO_free(tmpout);
    }

    /* Now Verify All Signatures */
    if (!(flags & PKCS7_NOSIGS))
        for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(sinfos); i++) {
            si = sk_PKCS7_SIGNER_INFO_value(sinfos, i);
            signer = sk_X509_value(signers, i);
            j = PKCS7_signatureVerify(p7bio, p7, si, signer);
            if (j <= 0) {
                PKCS7err(PKCS7_F_PKCS7_VERIFY, PKCS7_R_SIGNATURE_FAILURE);
                goto err;
            }
        }

    ret = 1;

 err:

    if (tmpin == indata) {
        if (indata)
            BIO_pop(p7bio);
    }
    BIO_free_all(p7bio);

    sk_X509_free(signers);

    return ret;
}

STACK_OF(X509) *PKCS7_get0_signers(PKCS7 *p7, STACK_OF(X509) *certs,
                                   int flags)
{
    STACK_OF(X509) *signers;
    STACK_OF(PKCS7_SIGNER_INFO) *sinfos;
    PKCS7_SIGNER_INFO *si;
    PKCS7_ISSUER_AND_SERIAL *ias;
    X509 *signer;
    int i;

    if (!p7) {
        PKCS7err(PKCS7_F_PKCS7_GET0_SIGNERS, PKCS7_R_INVALID_NULL_POINTER);
        return NULL;
    }

    if (!PKCS7_type_is_signed(p7)) {
        PKCS7err(PKCS7_F_PKCS7_GET0_SIGNERS, PKCS7_R_WRONG_CONTENT_TYPE);
        return NULL;
    }

    /* Collect all the signers together */

    sinfos = PKCS7_get_signer_info(p7);

    if (sk_PKCS7_SIGNER_INFO_num(sinfos) <= 0) {
        PKCS7err(PKCS7_F_PKCS7_GET0_SIGNERS, PKCS7_R_NO_SIGNERS);
        return 0;
    }

    if (!(signers = sk_X509_new_null())) {
        PKCS7err(PKCS7_F_PKCS7_GET0_SIGNERS, ERR_R_MALLOC_FAILURE);
        return NULL;
    }

    for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(sinfos); i++) {
        si = sk_PKCS7_SIGNER_INFO_value(sinfos, i);
        ias = si->issuer_and_serial;
        signer = NULL;
        /* If any certificates passed they take priority */
        if (certs)
            signer = X509_find_by_issuer_and_serial(certs,
                                                    ias->issuer, ias->serial);
        if (!signer && !(flags & PKCS7_NOINTERN)
            && p7->d.sign->cert)
            signer =
                X509_find_by_issuer_and_serial(p7->d.sign->cert,
                                               ias->issuer, ias->serial);
        if (!signer) {
            PKCS7err(PKCS7_F_PKCS7_GET0_SIGNERS,
                     PKCS7_R_SIGNER_CERTIFICATE_NOT_FOUND);
            sk_X509_free(signers);
            return 0;
        }

        if (!sk_X509_push(signers, signer)) {
            sk_X509_free(signers);
            return NULL;
        }
    }
    return signers;
}

/* Build a complete PKCS#7 enveloped data */

PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher,
                     int flags)
{
    PKCS7 *p7;
    BIO *p7bio = NULL;
    int i;
    X509 *x509;
    if (!(p7 = PKCS7_new())) {
        PKCS7err(PKCS7_F_PKCS7_ENCRYPT, ERR_R_MALLOC_FAILURE);
        return NULL;
    }

    if (!PKCS7_set_type(p7, NID_pkcs7_enveloped))
        goto err;
    if (!PKCS7_set_cipher(p7, cipher)) {
        PKCS7err(PKCS7_F_PKCS7_ENCRYPT, PKCS7_R_ERROR_SETTING_CIPHER);
        goto err;
    }

    for (i = 0; i < sk_X509_num(certs); i++) {
        x509 = sk_X509_value(certs, i);
        if (!PKCS7_add_recipient(p7, x509)) {
            PKCS7err(PKCS7_F_PKCS7_ENCRYPT, PKCS7_R_ERROR_ADDING_RECIPIENT);
            goto err;
        }
    }

    if (flags & PKCS7_STREAM)
        return p7;

    if (PKCS7_final(p7, in, flags))
        return p7;

 err:

    BIO_free_all(p7bio);
    PKCS7_free(p7);
    return NULL;

}

int PKCS7_decrypt(PKCS7 *p7, EVP_PKEY *pkey, X509 *cert, BIO *data, int flags)
{
    BIO *tmpmem;
    int ret, i;
    char buf[4096];

    if (!p7) {
        PKCS7err(PKCS7_F_PKCS7_DECRYPT, PKCS7_R_INVALID_NULL_POINTER);
        return 0;
    }

    if (!PKCS7_type_is_enveloped(p7)) {
        PKCS7err(PKCS7_F_PKCS7_DECRYPT, PKCS7_R_WRONG_CONTENT_TYPE);
        return 0;
    }

    if (cert && !X509_check_private_key(cert, pkey)) {
        PKCS7err(PKCS7_F_PKCS7_DECRYPT,
                 PKCS7_R_PRIVATE_KEY_DOES_NOT_MATCH_CERTIFICATE);
        return 0;
    }

    if (!(tmpmem = PKCS7_dataDecode(p7, pkey, NULL, cert))) {
        PKCS7err(PKCS7_F_PKCS7_DECRYPT, PKCS7_R_DECRYPT_ERROR);
        return 0;
    }

    if (flags & PKCS7_TEXT) {
        BIO *tmpbuf, *bread;
        /* Encrypt BIOs can't do BIO_gets() so add a buffer BIO */
        if (!(tmpbuf = BIO_new(BIO_f_buffer()))) {
            PKCS7err(PKCS7_F_PKCS7_DECRYPT, ERR_R_MALLOC_FAILURE);
            BIO_free_all(tmpmem);
            return 0;
        }
        if (!(bread = BIO_push(tmpbuf, tmpmem))) {
            PKCS7err(PKCS7_F_PKCS7_DECRYPT, ERR_R_MALLOC_FAILURE);
            BIO_free_all(tmpbuf);
            BIO_free_all(tmpmem);
            return 0;
        }
        ret = SMIME_text(bread, data);
        if (ret > 0 && BIO_method_type(tmpmem) == BIO_TYPE_CIPHER) {
            if (!BIO_get_cipher_status(tmpmem))
                ret = 0;
        }
        BIO_free_all(bread);
        return ret;
    } else {
        for (;;) {
            i = BIO_read(tmpmem, buf, sizeof(buf));
            if (i <= 0) {
                ret = 1;
                if (BIO_method_type(tmpmem) == BIO_TYPE_CIPHER) {
                    if (!BIO_get_cipher_status(tmpmem))
                        ret = 0;
                }

                break;
            }
            if (BIO_write(data, buf, i) != i) {
                ret = 0;
                break;
            }
        }
        BIO_free_all(tmpmem);
        return ret;
    }
}