/*      $OpenBSD: ct_oct.c,v 1.10 2025/05/10 05:54:38 tb Exp $ */
/*
 * Written by Rob Stradling (rob@comodo.com) and Stephen Henson
 * (steve@openssl.org) for the OpenSSL project 2014.
 */
/* ====================================================================
 * Copyright (c) 2014 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).
 *
 */

#ifdef OPENSSL_NO_CT
# error "CT is disabled"
#endif

#include <limits.h>
#include <string.h>

#include <openssl/asn1.h>
#include <openssl/buffer.h>
#include <openssl/ct.h>

#include "bytestring.h"
#include "ct_local.h"
#include "err_local.h"

int
o2i_SCT_signature(SCT *sct, CBS *cbs)
{
        uint8_t hash_alg, sig_alg;
        CBS signature;

        if (sct->version != SCT_VERSION_V1) {
                CTerror(CT_R_UNSUPPORTED_VERSION);
                return 0;
        }

        /*
         * Parse a digitally-signed element - see RFC 6962 section 3.2 and
         * RFC 5246 sections 4.7 and 7.4.1.4.1.
         */
        if (!CBS_get_u8(cbs, &hash_alg))
                goto err_invalid;
        if (!CBS_get_u8(cbs, &sig_alg))
                goto err_invalid;
        if (!CBS_get_u16_length_prefixed(cbs, &signature))
                goto err_invalid;
        if (CBS_len(cbs) != 0)
                goto err_invalid;

        /*
         * Reject empty signatures since they are invalid for all supported
         * algorithms (this really should be done by SCT_set1_signature()).
         */
        if (CBS_len(&signature) == 0)
                goto err_invalid;

        sct->hash_alg = hash_alg;
        sct->sig_alg = sig_alg;

        if (SCT_get_signature_nid(sct) == NID_undef)
                goto err_invalid;

        if (!SCT_set1_signature(sct, CBS_data(&signature), CBS_len(&signature)))
                return 0;

        return 1;

 err_invalid:
        CTerror(CT_R_SCT_INVALID_SIGNATURE);
        return 0;
}

static int
o2i_SCT_internal(SCT **out_sct, CBS *cbs)
{
        SCT *sct = NULL;
        uint8_t version;

        *out_sct = NULL;

        if ((sct = SCT_new()) == NULL)
                goto err;

        if (CBS_len(cbs) > MAX_SCT_SIZE)
                goto err_invalid;
        if (!CBS_peek_u8(cbs, &version))
                goto err_invalid;

        sct->version = version;

        if (version == SCT_VERSION_V1) {
                CBS extensions, log_id;
                uint64_t timestamp;

                /*
                 * Parse a v1 SignedCertificateTimestamp - see RFC 6962
                 * section 3.2.
                 */
                if (!CBS_get_u8(cbs, &version))
                        goto err_invalid;
                if (!CBS_get_bytes(cbs, &log_id, CT_V1_LOG_ID_LEN))
                        goto err_invalid;
                if (!CBS_get_u64(cbs, &timestamp))
                        goto err_invalid;
                if (!CBS_get_u16_length_prefixed(cbs, &extensions))
                        goto err_invalid;

                if (!CBS_stow(&log_id, &sct->log_id, &sct->log_id_len))
                        goto err;

                sct->timestamp = timestamp;

                if (!CBS_stow(&extensions, &sct->ext, &sct->ext_len))
                        goto err;

                if (!o2i_SCT_signature(sct, cbs))
                        goto err;

                if (CBS_len(cbs) != 0)
                        goto err_invalid;
        } else {
                /* If not V1 just cache encoding. */
                if (!CBS_stow(cbs, &sct->sct, &sct->sct_len))
                        goto err;
        }

        *out_sct = sct;

        return 1;

 err_invalid:
        CTerror(CT_R_SCT_INVALID);
 err:
        SCT_free(sct);

        return 0;
}

SCT *
o2i_SCT(SCT **psct, const unsigned char **in, size_t len)
{
        SCT *sct;
        CBS cbs;

        CBS_init(&cbs, *in, len);

        if (psct != NULL) {
                SCT_free(*psct);
                *psct = NULL;
        }

        if (!o2i_SCT_internal(&sct, &cbs))
                return NULL;

        if (psct != NULL)
                *psct = sct;

        *in = CBS_data(&cbs);

        return sct;
}
LCRYPTO_ALIAS(o2i_SCT);

int
i2o_SCT_signature(const SCT *sct, unsigned char **out)
{
        size_t len;
        unsigned char *p = NULL, *pstart = NULL;

        if (!SCT_signature_is_complete(sct)) {
                CTerror(CT_R_SCT_INVALID_SIGNATURE);
                goto err;
        }

        if (sct->version != SCT_VERSION_V1) {
                CTerror(CT_R_UNSUPPORTED_VERSION);
                goto err;
        }

        /*
         * (1 byte) Hash algorithm
         * (1 byte) Signature algorithm
         * (2 bytes + ?) Signature
         */
        len = 4 + sct->sig_len;

        if (out != NULL) {
                if (*out != NULL) {
                        p = *out;
                        *out += len;
                } else {
                        pstart = p = malloc(len);
                        if (p == NULL) {
                                CTerror(ERR_R_MALLOC_FAILURE);
                                goto err;
                        }
                        *out = p;
                }

                *p++ = sct->hash_alg;
                *p++ = sct->sig_alg;
                s2n(sct->sig_len, p);
                memcpy(p, sct->sig, sct->sig_len);
        }

        return len;
 err:
        free(pstart);
        return -1;
}

int
i2o_SCT(const SCT *sct, unsigned char **out)
{
        size_t len;
        unsigned char *p = NULL, *pstart = NULL;

        if (!SCT_is_complete(sct)) {
                CTerror(CT_R_SCT_NOT_SET);
                goto err;
        }
        /*
         * Fixed-length header: struct { (1 byte) Version sct_version; (32 bytes)
         * log_id id; (8 bytes) uint64 timestamp; (2 bytes + ?) CtExtensions
         * extensions; (1 byte) Hash algorithm (1 byte) Signature algorithm (2
         * bytes + ?) Signature
         */
        if (sct->version == SCT_VERSION_V1)
                len = 43 + sct->ext_len + 4 + sct->sig_len;
        else
                len = sct->sct_len;

        if (out == NULL)
                return len;

        if (*out != NULL) {
                p = *out;
                *out += len;
        } else {
                pstart = p = malloc(len);
                if (p == NULL) {
                        CTerror(ERR_R_MALLOC_FAILURE);
                        goto err;
                }
                *out = p;
        }

        if (sct->version == SCT_VERSION_V1) {
                *p++ = sct->version;
                memcpy(p, sct->log_id, CT_V1_HASHLEN);
                p += CT_V1_HASHLEN;
                l2n8(sct->timestamp, p);
                s2n(sct->ext_len, p);
                if (sct->ext_len > 0) {
                        memcpy(p, sct->ext, sct->ext_len);
                        p += sct->ext_len;
                }
                if (i2o_SCT_signature(sct, &p) <= 0)
                        goto err;
        } else {
                memcpy(p, sct->sct, len);
        }

        return len;
 err:
        free(pstart);
        return -1;
}
LCRYPTO_ALIAS(i2o_SCT);

STACK_OF(SCT) *
o2i_SCT_LIST(STACK_OF(SCT) **out_scts, const unsigned char **pp, size_t len)
{
        CBS cbs, cbs_scts, cbs_sct;
        STACK_OF(SCT) *scts = NULL;

        CBS_init(&cbs, *pp, len);

        if (CBS_len(&cbs) > MAX_SCT_LIST_SIZE)
                goto err_invalid;
        if (!CBS_get_u16_length_prefixed(&cbs, &cbs_scts))
                goto err_invalid;
        if (CBS_len(&cbs) != 0)
                goto err_invalid;

        if (out_scts != NULL) {
                SCT_LIST_free(*out_scts);
                *out_scts = NULL;
        }

        if ((scts = sk_SCT_new_null()) == NULL)
                return NULL;

        while (CBS_len(&cbs_scts) > 0) {
                SCT *sct;

                if (!CBS_get_u16_length_prefixed(&cbs_scts, &cbs_sct))
                        goto err_invalid;

                if (!o2i_SCT_internal(&sct, &cbs_sct))
                        goto err;
                if (!sk_SCT_push(scts, sct)) {
                        SCT_free(sct);
                        goto err;
                }
        }

        if (out_scts != NULL)
                *out_scts = scts;

        *pp = CBS_data(&cbs);

        return scts;

 err_invalid:
        CTerror(CT_R_SCT_LIST_INVALID);
 err:
        SCT_LIST_free(scts);

        return NULL;
}
LCRYPTO_ALIAS(o2i_SCT_LIST);

int
i2o_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **pp)
{
        int len, sct_len, i, is_pp_new = 0;
        size_t len2;
        unsigned char *p = NULL, *p2;

        if (pp != NULL) {
                if (*pp == NULL) {
                        if ((len = i2o_SCT_LIST(a, NULL)) == -1) {
                                CTerror(CT_R_SCT_LIST_INVALID);
                                return -1;
                        }
                        if ((*pp = malloc(len)) == NULL) {
                                CTerror(ERR_R_MALLOC_FAILURE);
                                return -1;
                        }
                        is_pp_new = 1;
                }
                p = *pp + 2;
        }

        len2 = 2;
        for (i = 0; i < sk_SCT_num(a); i++) {
                if (pp != NULL) {
                        p2 = p;
                        p += 2;
                        if ((sct_len = i2o_SCT(sk_SCT_value(a, i), &p)) == -1)
                                goto err;
                        s2n(sct_len, p2);
                } else {
                        if ((sct_len = i2o_SCT(sk_SCT_value(a, i), NULL)) == -1)
                                goto err;
                }
                len2 += 2 + sct_len;
        }

        if (len2 > MAX_SCT_LIST_SIZE)
                goto err;

        if (pp != NULL) {
                p = *pp;
                s2n(len2 - 2, p);
                if (!is_pp_new)
                        *pp += len2;
        }
        return len2;

 err:
        if (is_pp_new) {
                free(*pp);
                *pp = NULL;
        }
        return -1;
}
LCRYPTO_ALIAS(i2o_SCT_LIST);

STACK_OF(SCT) *
d2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp, long len)
{
        ASN1_OCTET_STRING *oct = NULL;
        STACK_OF(SCT) *sk = NULL;
        const unsigned char *p;

        p = *pp;
        if (d2i_ASN1_OCTET_STRING(&oct, &p, len) == NULL)
                return NULL;

        p = oct->data;
        if ((sk = o2i_SCT_LIST(a, &p, oct->length)) != NULL)
                *pp += len;

        ASN1_OCTET_STRING_free(oct);
        return sk;
}
LCRYPTO_ALIAS(d2i_SCT_LIST);

int
i2d_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **out)
{
        ASN1_OCTET_STRING oct;
        int len;

        oct.data = NULL;
        if ((oct.length = i2o_SCT_LIST(a, &oct.data)) == -1)
                return -1;

        len = i2d_ASN1_OCTET_STRING(&oct, out);
        free(oct.data);
        return len;
}
LCRYPTO_ALIAS(i2d_SCT_LIST);