/* $OpenBSD: ssl_asn1.c,v 1.69 2024/07/22 14:47:15 jsing Exp $ */
/*
 * Copyright (c) 2016 Joel Sing <jsing@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <limits.h>

#include <openssl/ssl.h>
#include <openssl/x509.h>

#include "bytestring.h"
#include "ssl_local.h"

#define SSLASN1_TAG     (CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC)
#define SSLASN1_TIME_TAG                (SSLASN1_TAG | 1)
#define SSLASN1_TIMEOUT_TAG             (SSLASN1_TAG | 2)
#define SSLASN1_PEER_CERT_TAG           (SSLASN1_TAG | 3)
#define SSLASN1_SESSION_ID_CTX_TAG      (SSLASN1_TAG | 4)
#define SSLASN1_VERIFY_RESULT_TAG       (SSLASN1_TAG | 5)
#define SSLASN1_HOSTNAME_TAG            (SSLASN1_TAG | 6)
#define SSLASN1_LIFETIME_TAG            (SSLASN1_TAG | 9)
#define SSLASN1_TICKET_TAG              (SSLASN1_TAG | 10)

static uint64_t
time_max(void)
{
        if (sizeof(time_t) == sizeof(int32_t))
                return INT32_MAX;
        if (sizeof(time_t) == sizeof(int64_t))
                return INT64_MAX;
        return 0;
}

static int
SSL_SESSION_encode(SSL_SESSION *s, unsigned char **out, size_t *out_len,
    int ticket_encoding)
{
        CBB cbb, session, cipher_suite, session_id, master_key, time, timeout;
        CBB peer_cert, sidctx, verify_result, hostname, lifetime, ticket, value;
        unsigned char *peer_cert_bytes = NULL;
        int len, rv = 0;

        if (!CBB_init(&cbb, 0))
                goto err;

        if (!CBB_add_asn1(&cbb, &session, CBS_ASN1_SEQUENCE))
                goto err;

        /* Session ASN1 version. */
        if (!CBB_add_asn1_uint64(&session, SSL_SESSION_ASN1_VERSION))
                goto err;

        /* TLS/SSL protocol version. */
        if (s->ssl_version < 0)
                goto err;
        if (!CBB_add_asn1_uint64(&session, s->ssl_version))
                goto err;

        /* Cipher suite value. */
        if (!CBB_add_asn1(&session, &cipher_suite, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBB_add_u16(&cipher_suite, s->cipher_value))
                goto err;

        /* Session ID - zero length for a ticket. */
        if (!CBB_add_asn1(&session, &session_id, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBB_add_bytes(&session_id, s->session_id,
            ticket_encoding ? 0 : s->session_id_length))
                goto err;

        /* Master key. */
        if (!CBB_add_asn1(&session, &master_key, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBB_add_bytes(&master_key, s->master_key, s->master_key_length))
                goto err;

        /* Time [1]. */
        if (s->time != 0) {
                if (s->time < 0)
                        goto err;
                if (!CBB_add_asn1(&session, &time, SSLASN1_TIME_TAG))
                        goto err;
                if (!CBB_add_asn1_uint64(&time, s->time))
                        goto err;
        }

        /* Timeout [2]. */
        if (s->timeout != 0) {
                if (s->timeout < 0)
                        goto err;
                if (!CBB_add_asn1(&session, &timeout, SSLASN1_TIMEOUT_TAG))
                        goto err;
                if (!CBB_add_asn1_uint64(&timeout, s->timeout))
                        goto err;
        }

        /* Peer certificate [3]. */
        if (s->peer_cert != NULL) {
                if ((len = i2d_X509(s->peer_cert, &peer_cert_bytes)) <= 0)
                        goto err;
                if (!CBB_add_asn1(&session, &peer_cert, SSLASN1_PEER_CERT_TAG))
                        goto err;
                if (!CBB_add_bytes(&peer_cert, peer_cert_bytes, len))
                        goto err;
        }

        /* Session ID context [4]. */
        /* XXX - Actually handle this as optional? */
        if (!CBB_add_asn1(&session, &sidctx, SSLASN1_SESSION_ID_CTX_TAG))
                goto err;
        if (!CBB_add_asn1(&sidctx, &value, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBB_add_bytes(&value, s->sid_ctx, s->sid_ctx_length))
                goto err;

        /* Verify result [5]. */
        if (s->verify_result != X509_V_OK) {
                if (s->verify_result < 0)
                        goto err;
                if (!CBB_add_asn1(&session, &verify_result,
                    SSLASN1_VERIFY_RESULT_TAG))
                        goto err;
                if (!CBB_add_asn1_uint64(&verify_result, s->verify_result))
                        goto err;
        }

        /* Hostname [6]. */
        if (s->tlsext_hostname != NULL) {
                if (!CBB_add_asn1(&session, &hostname, SSLASN1_HOSTNAME_TAG))
                        goto err;
                if (!CBB_add_asn1(&hostname, &value, CBS_ASN1_OCTETSTRING))
                        goto err;
                if (!CBB_add_bytes(&value, (const uint8_t *)s->tlsext_hostname,
                    strlen(s->tlsext_hostname)))
                        goto err;
        }

        /* PSK identity hint [7]. */
        /* PSK identity [8]. */

        /* Ticket lifetime hint [9]. */
        if (s->tlsext_tick_lifetime_hint > 0) {
                if (!CBB_add_asn1(&session, &lifetime, SSLASN1_LIFETIME_TAG))
                        goto err;
                if (!CBB_add_asn1_uint64(&lifetime,
                    s->tlsext_tick_lifetime_hint))
                        goto err;
        }

        /* Ticket [10]. */
        if (s->tlsext_tick != NULL) {
                if (!CBB_add_asn1(&session, &ticket, SSLASN1_TICKET_TAG))
                        goto err;
                if (!CBB_add_asn1(&ticket, &value, CBS_ASN1_OCTETSTRING))
                        goto err;
                if (!CBB_add_bytes(&value, s->tlsext_tick, s->tlsext_ticklen))
                        goto err;
        }

        /* Compression method [11]. */
        /* SRP username [12]. */

        if (!CBB_finish(&cbb, out, out_len))
                goto err;

        rv = 1;

 err:
        CBB_cleanup(&cbb);
        free(peer_cert_bytes);

        return rv;
}

int
SSL_SESSION_ticket(SSL_SESSION *ss, unsigned char **out, size_t *out_len)
{
        if (ss == NULL)
                return 0;

        if (ss->cipher_value == 0)
                return 0;

        return SSL_SESSION_encode(ss, out, out_len, 1);
}

int
i2d_SSL_SESSION(SSL_SESSION *ss, unsigned char **pp)
{
        unsigned char *data = NULL;
        size_t data_len = 0;
        int rv = -1;

        if (ss == NULL)
                return 0;

        if (ss->cipher_value == 0)
                return 0;

        if (!SSL_SESSION_encode(ss, &data, &data_len, 0))
                goto err;

        if (data_len > INT_MAX)
                goto err;

        if (pp != NULL) {
                if (*pp == NULL) {
                        *pp = data;
                        data = NULL;
                } else {
                        memcpy(*pp, data, data_len);
                        *pp += data_len;
                }
        }

        rv = (int)data_len;

 err:
        freezero(data, data_len);

        return rv;
}
LSSL_ALIAS(i2d_SSL_SESSION);

SSL_SESSION *
d2i_SSL_SESSION(SSL_SESSION **a, const unsigned char **pp, long length)
{
        CBS cbs, session, cipher_suite, session_id, master_key, peer_cert;
        CBS hostname, ticket;
        uint64_t version, tls_version, stime, timeout, verify_result, lifetime;
        const unsigned char *peer_cert_bytes;
        SSL_SESSION *s = NULL;
        size_t data_len;
        int present;

        if (a != NULL)
                s = *a;

        if (s == NULL) {
                if ((s = SSL_SESSION_new()) == NULL) {
                        SSLerrorx(ERR_R_MALLOC_FAILURE);
                        return (NULL);
                }
        }

        CBS_init(&cbs, *pp, length);

        if (!CBS_get_asn1(&cbs, &session, CBS_ASN1_SEQUENCE))
                goto err;

        /* Session ASN1 version. */
        if (!CBS_get_asn1_uint64(&session, &version))
                goto err;
        if (version != SSL_SESSION_ASN1_VERSION)
                goto err;

        /* TLS/SSL Protocol Version. */
        if (!CBS_get_asn1_uint64(&session, &tls_version))
                goto err;
        if (tls_version > INT_MAX)
                goto err;
        s->ssl_version = (int)tls_version;

        /* Cipher suite value. */
        if (!CBS_get_asn1(&session, &cipher_suite, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBS_get_u16(&cipher_suite, &s->cipher_value))
                goto err;
        if (CBS_len(&cipher_suite) != 0)
                goto err;

        /* Session ID. */
        if (!CBS_get_asn1(&session, &session_id, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBS_write_bytes(&session_id, s->session_id, sizeof(s->session_id),
            &s->session_id_length))
                goto err;

        /* Master key. */
        if (!CBS_get_asn1(&session, &master_key, CBS_ASN1_OCTETSTRING))
                goto err;
        if (!CBS_write_bytes(&master_key, s->master_key, sizeof(s->master_key),
            &s->master_key_length))
                goto err;

        /* Time [1]. */
        s->time = time(NULL);
        if (!CBS_get_optional_asn1_uint64(&session, &stime, SSLASN1_TIME_TAG,
            0))
                goto err;
        if (stime > time_max())
                goto err;
        if (stime != 0)
                s->time = (time_t)stime;

        /* Timeout [2]. */
        s->timeout = 3;
        if (!CBS_get_optional_asn1_uint64(&session, &timeout,
            SSLASN1_TIMEOUT_TAG, 0))
                goto err;
        if (timeout > LONG_MAX)
                goto err;
        if (timeout != 0)
                s->timeout = (long)timeout;

        /* Peer certificate [3]. */
        X509_free(s->peer_cert);
        s->peer_cert = NULL;
        if (!CBS_get_optional_asn1(&session, &peer_cert, &present,
            SSLASN1_PEER_CERT_TAG))
                goto err;
        if (present) {
                data_len = CBS_len(&peer_cert);
                if (data_len > LONG_MAX)
                        goto err;
                peer_cert_bytes = CBS_data(&peer_cert);
                if (d2i_X509(&s->peer_cert, &peer_cert_bytes,
                    (long)data_len) == NULL)
                        goto err;
        }

        /* Session ID context [4]. */
        s->sid_ctx_length = 0;
        if (!CBS_get_optional_asn1_octet_string(&session, &session_id, &present,
            SSLASN1_SESSION_ID_CTX_TAG))
                goto err;
        if (present) {
                if (!CBS_write_bytes(&session_id, (uint8_t *)&s->sid_ctx,
                    sizeof(s->sid_ctx), &s->sid_ctx_length))
                        goto err;
        }

        /* Verify result [5]. */
        s->verify_result = X509_V_OK;
        if (!CBS_get_optional_asn1_uint64(&session, &verify_result,
            SSLASN1_VERIFY_RESULT_TAG, X509_V_OK))
                goto err;
        if (verify_result > LONG_MAX)
                goto err;
        s->verify_result = (long)verify_result;

        /* Hostname [6]. */
        free(s->tlsext_hostname);
        s->tlsext_hostname = NULL;
        if (!CBS_get_optional_asn1_octet_string(&session, &hostname, &present,
            SSLASN1_HOSTNAME_TAG))
                goto err;
        if (present) {
                if (CBS_contains_zero_byte(&hostname))
                        goto err;
                if (!CBS_strdup(&hostname, &s->tlsext_hostname))
                        goto err;
        }

        /* PSK identity hint [7]. */
        /* PSK identity [8]. */

        /* Ticket lifetime [9]. */
        s->tlsext_tick_lifetime_hint = 0;
        if (!CBS_get_optional_asn1_uint64(&session, &lifetime,
            SSLASN1_LIFETIME_TAG, 0))
                goto err;
        if (lifetime > UINT32_MAX)
                goto err;
        if (lifetime > 0)
                s->tlsext_tick_lifetime_hint = (uint32_t)lifetime;

        /* Ticket [10]. */
        free(s->tlsext_tick);
        s->tlsext_tick = NULL;
        if (!CBS_get_optional_asn1_octet_string(&session, &ticket, &present,
            SSLASN1_TICKET_TAG))
                goto err;
        if (present) {
                if (!CBS_stow(&ticket, &s->tlsext_tick, &s->tlsext_ticklen))
                        goto err;
        }

        /* Compression method [11]. */
        /* SRP username [12]. */

        *pp = CBS_data(&cbs);

        if (a != NULL)
                *a = s;

        return (s);

 err:
        ERR_asprintf_error_data("offset=%d", (int)(CBS_data(&cbs) - *pp));

        if (s != NULL && (a == NULL || *a != s))
                SSL_SESSION_free(s);

        return (NULL);
}
LSSL_ALIAS(d2i_SSL_SESSION);