/* $OpenBSD: pk7_smime.c,v 1.29 2025/12/20 07:22:43 tb Exp $ */
/* 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 <openssl/x509.h>
#include <openssl/x509v3.h>

#include "err_local.h"
#include "x509_local.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())) {
                PKCS7error(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)) {
                PKCS7error(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;
}
LCRYPTO_ALIAS(PKCS7_sign);

int
PKCS7_final(PKCS7 *p7, BIO *data, int flags)
{
        BIO *p7bio;
        int ret = 0;

        if (!(p7bio = PKCS7_dataInit(p7, NULL))) {
                PKCS7error(ERR_R_MALLOC_FAILURE);
                return 0;
        }

        SMIME_crlf_copy(data, p7bio, flags);

        (void)BIO_flush(p7bio);

        if (!PKCS7_dataFinal(p7, p7bio)) {
                PKCS7error(PKCS7_R_PKCS7_DATASIGN);
                goto err;
        }

        ret = 1;

err:
        BIO_free_all(p7bio);

        return ret;
}
LCRYPTO_ALIAS(PKCS7_final);

/* 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;
}

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)) {
                PKCS7error(PKCS7_R_PRIVATE_KEY_DOES_NOT_MATCH_CERTIFICATE);
                return NULL;
        }

        if (!(si = PKCS7_add_signature(p7, signcert, pkey, md))) {
                PKCS7error(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())) {
                                PKCS7error(ERR_R_MALLOC_FAILURE);
                                goto err;
                        }
                        if (!add_cipher_smcap(smcap, NID_aes_256_cbc, -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:
        if (smcap)
                sk_X509_ALGOR_pop_free(smcap, X509_ALGOR_free);
        return NULL;
}
LCRYPTO_ALIAS(PKCS7_sign_add_signer);

/* 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);

        PKCS7error(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) {
                PKCS7error(PKCS7_R_INVALID_NULL_POINTER);
                return 0;
        }

        if (!PKCS7_type_is_signed(p7)) {
                PKCS7error(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) {
                PKCS7error(PKCS7_R_NO_CONTENT);
                return 0;
        }

        if ((flags & PKCS7_NO_DUAL_CONTENT) != 0) {
                /*
                 * This was originally "#if 0" because we thought that only old
                 * broken Netscape did this.  It turns out that Authenticode
                 * uses this kind of "extended" PKCS7 format, and things like
                 * UEFI secure boot and tools like osslsigncode need it.  In
                 * Authenticode the verification process is different, but the
                 * existing PKCS7 verification works.
                 */
                if (!PKCS7_get_detached(p7) && indata != NULL) {
                        PKCS7error(PKCS7_R_CONTENT_AND_DATA_PRESENT);
                        return 0;
                }
        }

        sinfos = PKCS7_get_signer_info(p7);

        if (!sinfos || !sk_PKCS7_SIGNER_INFO_num(sinfos)) {
                PKCS7error(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)) {
                                        PKCS7error(ERR_R_X509_LIB);
                                        sk_X509_free(signers);
                                        return 0;
                                }
                                if (X509_STORE_CTX_set_default(&cert_ctx,
                                    "smime_sign") == 0) {
                                        sk_X509_free(signers);
                                        return 0;
                                }
                        } else if (!X509_STORE_CTX_init(&cert_ctx, store,
                            signer, NULL)) {
                                PKCS7error(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) {
                                PKCS7error(PKCS7_R_CERTIFICATE_VERIFY_ERROR);
                                ERR_asprintf_error_data("Verify error:%s",
                                    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) {
                        PKCS7error(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()))) {
                        PKCS7error(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)) {
                        PKCS7error(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) {
                                PKCS7error(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;
}
LCRYPTO_ALIAS(PKCS7_verify);

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) {
                PKCS7error(PKCS7_R_INVALID_NULL_POINTER);
                return NULL;
        }

        if (!PKCS7_type_is_signed(p7)) {
                PKCS7error(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) {
                PKCS7error(PKCS7_R_NO_SIGNERS);
                return 0;
        }

        if (!(signers = sk_X509_new_null())) {
                PKCS7error(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) {
                        PKCS7error(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;
}
LCRYPTO_ALIAS(PKCS7_get0_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())) {
                PKCS7error(ERR_R_MALLOC_FAILURE);
                return NULL;
        }

        if (!PKCS7_set_type(p7, NID_pkcs7_enveloped))
                goto err;
        if (!PKCS7_set_cipher(p7, cipher)) {
                PKCS7error(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)) {
                        PKCS7error(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;
}
LCRYPTO_ALIAS(PKCS7_encrypt);

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

        if (!p7) {
                PKCS7error(PKCS7_R_INVALID_NULL_POINTER);
                return 0;
        }

        if (!PKCS7_type_is_enveloped(p7)) {
                PKCS7error(PKCS7_R_WRONG_CONTENT_TYPE);
                return 0;
        }

        if (cert && !X509_check_private_key(cert, pkey)) {
                PKCS7error(PKCS7_R_PRIVATE_KEY_DOES_NOT_MATCH_CERTIFICATE);
                return 0;
        }

        if (!(tmpmem = PKCS7_dataDecode(p7, pkey, NULL, cert))) {
                PKCS7error(PKCS7_R_DECRYPT_ERROR);
                return 0;
        }

        if (flags & PKCS7_TEXT) {
                BIO *tmpbuf;

                /* Encrypt BIOs can't do BIO_gets() so add a buffer BIO */
                if (!(tmpbuf = BIO_new(BIO_f_buffer()))) {
                        PKCS7error(ERR_R_MALLOC_FAILURE);
                        BIO_free_all(tmpmem);
                        return 0;
                }
                BIO_push(tmpbuf, tmpmem);
                ret = SMIME_text(tmpbuf, data);
                if (ret > 0 && BIO_method_type(tmpmem) == BIO_TYPE_CIPHER) {
                        if (!BIO_get_cipher_status(tmpmem))
                                ret = 0;
                }
                BIO_free_all(tmpbuf);
                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;
        }
}
LCRYPTO_ALIAS(PKCS7_decrypt);