[thirdparty/openssl.git] / ssl / statem / extensions_cust.c

/*
 * Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/* Custom extension utility functions */

#include <assert.h>
#include <openssl/ct.h>
#include "../ssl_locl.h"
#include "statem_locl.h"

typedef struct {
    void *add_arg;
    custom_ext_add_cb add_cb;
    custom_ext_free_cb free_cb;
} custom_ext_add_cb_wrap;

typedef struct {
    void *parse_arg;
    custom_ext_parse_cb parse_cb;
} custom_ext_parse_cb_wrap;

/*
 * Provide thin wrapper callbacks which convert new style arguments to old style
 */
static int custom_ext_add_old_cb_wrap(SSL *s, unsigned int ext_type,
                                      unsigned int context,
                                      const unsigned char **out,
                                      size_t *outlen, X509 *x, size_t chainidx,
                                      int *al, void *add_arg)
{
    custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;

    if (add_cb_wrap->add_cb == NULL)
        return 1;

    return add_cb_wrap->add_cb(s, ext_type, out, outlen, al,
                               add_cb_wrap->add_arg);
}

static void custom_ext_free_old_cb_wrap(SSL *s, unsigned int ext_type,
                                        unsigned int context,
                                        const unsigned char *out, void *add_arg)
{
    custom_ext_add_cb_wrap *add_cb_wrap = (custom_ext_add_cb_wrap *)add_arg;

    if (add_cb_wrap->free_cb == NULL)
        return;

    add_cb_wrap->free_cb(s, ext_type, out, add_cb_wrap->add_arg);
}

static int custom_ext_parse_old_cb_wrap(SSL *s, unsigned int ext_type,
                                        unsigned int context,
                                        const unsigned char *in,
                                        size_t inlen, X509 *x, size_t chainidx,
                                        int *al, void *parse_arg)
{
    custom_ext_parse_cb_wrap *parse_cb_wrap =
        (custom_ext_parse_cb_wrap *)parse_arg;

    return parse_cb_wrap->parse_cb(s, ext_type, in, inlen, al,
                                   parse_cb_wrap->parse_arg);
}

/*
 * Find a custom extension from the list. The |server| param is there to
 * support the legacy API where custom extensions for client and server could
 * be set independently on the same SSL_CTX. It is set to 1 if we are trying
 * to find a method relevant to the server, 0 for the client, or -1 if we don't
 * care
 */
custom_ext_method *custom_ext_find(const custom_ext_methods *exts, int server,
                                   unsigned int ext_type, size_t *idx)
{
    size_t i;

    custom_ext_method *meth = exts->meths;
    for (i = 0; i < exts->meths_count; i++, meth++) {
        if (ext_type == meth->ext_type
                && (server == -1 || server == meth->server
                    || meth->server == -1)) {
            if (idx != NULL)
                *idx = i;
            return meth;
        }
    }
    return NULL;
}

/*
 * Initialise custom extensions flags to indicate neither sent nor received.
 */
void custom_ext_init(custom_ext_methods *exts)
{
    size_t i;
    custom_ext_method *meth = exts->meths;
    for (i = 0; i < exts->meths_count; i++, meth++)
        meth->ext_flags = 0;
}

/* Pass received custom extension data to the application for parsing. */
int custom_ext_parse(SSL *s, unsigned int context, unsigned int ext_type,
                     const unsigned char *ext_data, size_t ext_size, X509 *x,
                     size_t chainidx, int *al)
{
    custom_ext_methods *exts = &s->cert->custext;
    custom_ext_method *meth;
    int server = -1;

    if ((context & (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
        server = s->server;

    meth = custom_ext_find(exts, server, ext_type, NULL);
    /* If not found return success */
    if (!meth)
        return 1;

    /* Check if extension is defined for our protocol. If not, skip */
    if (!extension_is_relevant(s, meth->context, context))
        return 1;

    if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
                    | SSL_EXT_TLS1_3_SERVER_HELLO
                    | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
        /*
         * If it's ServerHello or EncryptedExtensions we can't have any
         * extensions not sent in ClientHello.
         */
        if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
            *al = TLS1_AD_UNSUPPORTED_EXTENSION;
            return 0;
        }
    }

    /*
     * Extensions received in the ClientHello are marked with the
     * SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
     * extensions in the ServerHello/EncryptedExtensions message
     */
    if ((context & SSL_EXT_CLIENT_HELLO) != 0)
        meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;

    /* If no parse function set return success */
    if (!meth->parse_cb)
        return 1;

    return meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
                          al, meth->parse_arg);
}

/*
 * Request custom extension data from the application and add to the return
 * buffer.
 */
int custom_ext_add(SSL *s, int context, WPACKET *pkt, X509 *x, size_t chainidx,
                   int maxversion, int *al)
{
    custom_ext_methods *exts = &s->cert->custext;
    custom_ext_method *meth;
    size_t i;

    for (i = 0; i < exts->meths_count; i++) {
        const unsigned char *out = NULL;
        size_t outlen = 0;

        meth = exts->meths + i;

        if (!should_add_extension(s, meth->context, context, maxversion))
            continue;

        if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
                        | SSL_EXT_TLS1_3_SERVER_HELLO
                        | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
            /*
             * For ServerHello/EncryptedExtensions only send extensions present
             * in ClientHello.
             */
            if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
                continue;
        }
        /*
         * We skip it if the callback is absent - except for a ClientHello where
         * we add an empty extension.
         */
        if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
            continue;

        if (meth->add_cb != NULL) {
            int cb_retval = 0;
            cb_retval = meth->add_cb(s, meth->ext_type, context, &out, &outlen,
                                     x, chainidx, al, meth->add_arg);
            if (cb_retval < 0)
                return 0;       /* error */
            if (cb_retval == 0)
                continue;       /* skip this extension */
        }

        if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
                || !WPACKET_start_sub_packet_u16(pkt)
                || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
                || !WPACKET_close(pkt)) {
            *al = SSL_AD_INTERNAL_ERROR;
            return 0;
        }
        if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
            /*
             * We can't send duplicates: code logic should prevent this.
             */
            assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
            /*
             * Indicate extension has been sent: this is both a sanity check to
             * ensure we don't send duplicate extensions and indicates that it
             * is not an error if the extension is present in ServerHello.
             */
            meth->ext_flags |= SSL_EXT_FLAG_SENT;
        }
        if (meth->free_cb)
            meth->free_cb(s, meth->ext_type, context, out, meth->add_arg);
    }
    return 1;
}

/* Copy table of custom extensions */
int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
{
    size_t i;
    int err = 0;

    if (src->meths_count > 0) {
        dst->meths =
            OPENSSL_memdup(src->meths,
                           sizeof(custom_ext_method) * src->meths_count);
        if (dst->meths == NULL)
            return 0;
        dst->meths_count = src->meths_count;

        for (i = 0; i < src->meths_count; i++) {
            custom_ext_method *methsrc = src->meths + i;
            custom_ext_method *methdst = dst->meths + i;

            if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
                continue;

            /*
             * We have found an old style API wrapper. We need to copy the
             * arguments too.
             */

            if (err) {
                methdst->add_arg = NULL;
                methdst->parse_arg = NULL;
                continue;
            }

            methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
                                              sizeof(custom_ext_add_cb_wrap));
            methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
                                            sizeof(custom_ext_parse_cb_wrap));

            if (methdst->add_arg == NULL || methdst->parse_arg == NULL)
                err = 1;
        }
    }

    if (err) {
        custom_exts_free(dst);
        return 0;
    }

    return 1;
}

void custom_exts_free(custom_ext_methods *exts)
{
    size_t i;

    for (i = 0; i < exts->meths_count; i++) {
        custom_ext_method *meth = exts->meths + i;

        if (meth->add_cb != custom_ext_add_old_cb_wrap)
            continue;

        /* Old style API wrapper. Need to free the arguments too */
        OPENSSL_free(meth->add_arg);
        OPENSSL_free(meth->parse_arg);
    }
    OPENSSL_free(exts->meths);
}

/* Return true if a client custom extension exists, false otherwise */
int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
{
    return custom_ext_find(&ctx->cert->custext, 0, ext_type, NULL) != NULL;
}

static int add_custom_ext_intern(SSL_CTX *ctx, int server,
                                 unsigned int ext_type,
                                 unsigned int context,
                                 custom_ext_add_cb_ex add_cb,
                                 custom_ext_free_cb_ex free_cb,
                                 void *add_arg,
                                 custom_ext_parse_cb_ex parse_cb,
                                 void *parse_arg)
{
    custom_ext_methods *exts = &ctx->cert->custext;
    custom_ext_method *meth, *tmp;

    /*
     * Check application error: if add_cb is not set free_cb will never be
     * called.
     */
    if (!add_cb && free_cb)
        return 0;

#ifndef OPENSSL_NO_CT
    /*
     * We don't want applications registering callbacks for SCT extensions
     * whilst simultaneously using the built-in SCT validation features, as
     * these two things may not play well together.
     */
    if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
            && (context & SSL_EXT_CLIENT_HELLO) != 0
            && SSL_CTX_ct_is_enabled(ctx))
        return 0;
#endif

    /*
     * Don't add if extension supported internally, but make exception
     * for extension types that previously were not supported, but now are.
     */
    if (SSL_extension_supported(ext_type)
            && ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
        return 0;

    /* Extension type must fit in 16 bits */
    if (ext_type > 0xffff)
        return 0;
    /* Search for duplicate */
    if (custom_ext_find(exts, server, ext_type, NULL))
        return 0;
    tmp = OPENSSL_realloc(exts->meths,
                          (exts->meths_count + 1) * sizeof(custom_ext_method));

    if (tmp == NULL)
        return 0;

    exts->meths = tmp;
    meth = exts->meths + exts->meths_count;
    memset(meth, 0, sizeof(*meth));
    meth->server = server;
    meth->context = context;
    meth->parse_cb = parse_cb;
    meth->add_cb = add_cb;
    meth->free_cb = free_cb;
    meth->ext_type = ext_type;
    meth->add_arg = add_arg;
    meth->parse_arg = parse_arg;
    exts->meths_count++;
    return 1;
}

static int add_old_custom_ext(SSL_CTX *ctx, int server, unsigned int ext_type,
                              unsigned int context,
                              custom_ext_add_cb add_cb,
                              custom_ext_free_cb free_cb,
                              void *add_arg,
                              custom_ext_parse_cb parse_cb, void *parse_arg)
{
    custom_ext_add_cb_wrap *add_cb_wrap
        = OPENSSL_malloc(sizeof(custom_ext_add_cb_wrap));
    custom_ext_parse_cb_wrap *parse_cb_wrap
        = OPENSSL_malloc(sizeof(custom_ext_parse_cb_wrap));
    int ret;

    if (add_cb_wrap == NULL || parse_cb_wrap == NULL) {
        OPENSSL_free(add_cb_wrap);
        OPENSSL_free(parse_cb_wrap);
        return 0;
    }

    add_cb_wrap->add_arg = add_arg;
    add_cb_wrap->add_cb = add_cb;
    add_cb_wrap->free_cb = free_cb;
    parse_cb_wrap->parse_arg = parse_arg;
    parse_cb_wrap->parse_cb = parse_cb;

    /*
     * TODO(TLS1.3): Is it possible with the old API to add custom exts for both
     * client and server for the same type in the same SSL_CTX? We don't handle
     * that yet.
     */
    ret = add_custom_ext_intern(ctx, server, ext_type,
                                context,
                                custom_ext_add_old_cb_wrap,
                                custom_ext_free_old_cb_wrap,
                                add_cb_wrap,
                                custom_ext_parse_old_cb_wrap,
                                parse_cb_wrap);

    if (!ret) {
        OPENSSL_free(add_cb_wrap);
        OPENSSL_free(parse_cb_wrap);
    }

    return ret;
}

/* Application level functions to add the old custom extension callbacks */
int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
                                  custom_ext_add_cb add_cb,
                                  custom_ext_free_cb free_cb,
                                  void *add_arg,
                                  custom_ext_parse_cb parse_cb, void *parse_arg)
{
    return add_old_custom_ext(ctx, 0, ext_type,
                              SSL_EXT_TLS1_2_AND_BELOW_ONLY
                              | SSL_EXT_CLIENT_HELLO
                              | SSL_EXT_TLS1_2_SERVER_HELLO
                              | SSL_EXT_IGNORE_ON_RESUMPTION,
                              add_cb, free_cb, add_arg, parse_cb, parse_arg);
}

int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
                                  custom_ext_add_cb add_cb,
                                  custom_ext_free_cb free_cb,
                                  void *add_arg,
                                  custom_ext_parse_cb parse_cb, void *parse_arg)
{
    return add_old_custom_ext(ctx, 1, ext_type,
                              SSL_EXT_TLS1_2_AND_BELOW_ONLY
                              | SSL_EXT_CLIENT_HELLO
                              | SSL_EXT_TLS1_2_SERVER_HELLO
                              | SSL_EXT_IGNORE_ON_RESUMPTION,
                              add_cb, free_cb, add_arg, parse_cb, parse_arg);
}

int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
                           unsigned int context,
                           custom_ext_add_cb_ex add_cb,
                           custom_ext_free_cb_ex free_cb,
                           void *add_arg,
                           custom_ext_parse_cb_ex parse_cb, void *parse_arg)
{
    return add_custom_ext_intern(ctx, -1, ext_type, context, add_cb, free_cb,
                                 add_arg, parse_cb, parse_arg);
}

int SSL_extension_supported(unsigned int ext_type)
{
    switch (ext_type) {
        /* Internally supported extensions. */
    case TLSEXT_TYPE_application_layer_protocol_negotiation:
#ifndef OPENSSL_NO_EC
    case TLSEXT_TYPE_ec_point_formats:
    case TLSEXT_TYPE_supported_groups:
    case TLSEXT_TYPE_key_share:
#endif
#ifndef OPENSSL_NO_NEXTPROTONEG
    case TLSEXT_TYPE_next_proto_neg:
#endif
    case TLSEXT_TYPE_padding:
    case TLSEXT_TYPE_renegotiate:
    case TLSEXT_TYPE_server_name:
    case TLSEXT_TYPE_session_ticket:
    case TLSEXT_TYPE_signature_algorithms:
#ifndef OPENSSL_NO_SRP
    case TLSEXT_TYPE_srp:
#endif
#ifndef OPENSSL_NO_OCSP
    case TLSEXT_TYPE_status_request:
#endif
#ifndef OPENSSL_NO_CT
    case TLSEXT_TYPE_signed_certificate_timestamp:
#endif
#ifndef OPENSSL_NO_SRTP
    case TLSEXT_TYPE_use_srtp:
#endif
    case TLSEXT_TYPE_encrypt_then_mac:
    case TLSEXT_TYPE_supported_versions:
    case TLSEXT_TYPE_extended_master_secret:
    case TLSEXT_TYPE_psk_kex_modes:
    case TLSEXT_TYPE_cookie:
    case TLSEXT_TYPE_early_data:
    case TLSEXT_TYPE_certificate_authorities:
    case TLSEXT_TYPE_psk:
        return 1;
    default:
        return 0;
    }
}
Commit	Line	Data
846e33c7 RS	1	/*
846e33c7 RS	2	* Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
ecf4d660	3	*
846e33c7 RS	4	* Licensed under the OpenSSL license (the "License"). You may not use
	5	* this file except in compliance with the License. You can obtain a copy
	6	* in the file LICENSE in the source distribution or at
	7	* https://www.openssl.org/source/license.html
ecf4d660 DSH	8	*/
	9
	10	/* Custom extension utility functions */
	11
43ae5eed	12	#include <assert.h>
3c27208f	13	#include <openssl/ct.h>
b443c845	14	#include "../ssl_locl.h"
43ae5eed	15	#include "statem_locl.h"
ecf4d660	16
43ae5eed MC	17	typedef struct {
	18	void *add_arg;
	19	custom_ext_add_cb add_cb;
	20	custom_ext_free_cb free_cb;
	21	} custom_ext_add_cb_wrap;
	22
	23	typedef struct {
	24	void *parse_arg;
	25	custom_ext_parse_cb parse_cb;
	26	} custom_ext_parse_cb_wrap;
	27
	28	/*
	29	* Provide thin wrapper callbacks which convert new style arguments to old style
	30	*/
	31	static int custom_ext_add_old_cb_wrap(SSL *s, unsigned int ext_type,
	32	unsigned int context,
	33	const unsigned char **out,
	34	size_t outlen, X509 x, size_t chainidx,
	35	int al, void add_arg)
	36	{
	37	custom_ext_add_cb_wrap add_cb_wrap = (custom_ext_add_cb_wrap )add_arg;
	38
	39	if (add_cb_wrap->add_cb == NULL)
	40	return 1;
	41
	42	return add_cb_wrap->add_cb(s, ext_type, out, outlen, al,
	43	add_cb_wrap->add_arg);
	44	}
	45
	46	static void custom_ext_free_old_cb_wrap(SSL *s, unsigned int ext_type,
	47	unsigned int context,
	48	const unsigned char out, void add_arg)
	49	{
	50	custom_ext_add_cb_wrap add_cb_wrap = (custom_ext_add_cb_wrap )add_arg;
	51
	52	if (add_cb_wrap->free_cb == NULL)
	53	return;
	54
	55	add_cb_wrap->free_cb(s, ext_type, out, add_cb_wrap->add_arg);
	56	}
	57
	58	static int custom_ext_parse_old_cb_wrap(SSL *s, unsigned int ext_type,
	59	unsigned int context,
	60	const unsigned char *in,
	61	size_t inlen, X509 *x, size_t chainidx,
	62	int al, void parse_arg)
	63	{
	64	custom_ext_parse_cb_wrap *parse_cb_wrap =
	65	(custom_ext_parse_cb_wrap *)parse_arg;
	66
	67	return parse_cb_wrap->parse_cb(s, ext_type, in, inlen, al,
	68	parse_cb_wrap->parse_arg);
	69	}
	70
	71	/*
	72	* Find a custom extension from the list. The \|server\| param is there to
	73	* support the legacy API where custom extensions for client and server could
	74	* be set independently on the same SSL_CTX. It is set to 1 if we are trying
	75	* to find a method relevant to the server, 0 for the client, or -1 if we don't
	76	* care
	77	*/
	78	custom_ext_method custom_ext_find(const custom_ext_methods exts, int server,
	79	unsigned int ext_type, size_t *idx)
0f113f3e MC	80	{
0f113f3e MC	81	size_t i;
43ae5eed	82
0f113f3e MC	83	custom_ext_method *meth = exts->meths;
0f113f3e MC	84	for (i = 0; i < exts->meths_count; i++, meth++) {
43ae5eed MC	85	if (ext_type == meth->ext_type
	86	&& (server == -1 \|\| server == meth->server
	87	\|\| meth->server == -1)) {
	88	if (idx != NULL)
	89	*idx = i;
0f113f3e	90	return meth;
43ae5eed	91	}
0f113f3e MC	92	}
	93	return NULL;
	94	}
	95
	96	/*
	97	* Initialise custom extensions flags to indicate neither sent nor received.
28ea0a0c DSH	98	*/
28ea0a0c DSH	99	void custom_ext_init(custom_ext_methods *exts)
0f113f3e MC	100	{
	101	size_t i;
	102	custom_ext_method *meth = exts->meths;
	103	for (i = 0; i < exts->meths_count; i++, meth++)
	104	meth->ext_flags = 0;
	105	}
ecf4d660	106
0cfefe4b	107	/* Pass received custom extension data to the application for parsing. */
43ae5eed MC	108	int custom_ext_parse(SSL *s, unsigned int context, unsigned int ext_type,
	109	const unsigned char ext_data, size_t ext_size, X509 x,
	110	size_t chainidx, int *al)
0f113f3e	111	{
43ae5eed	112	custom_ext_methods *exts = &s->cert->custext;
0f113f3e	113	custom_ext_method *meth;
43ae5eed MC	114	int server = -1;
	115
	116	if ((context & (SSL_EXT_CLIENT_HELLO \| SSL_EXT_TLS1_2_SERVER_HELLO)) != 0)
	117	server = s->server;
	118
	119	meth = custom_ext_find(exts, server, ext_type, NULL);
0f113f3e MC	120	/* If not found return success */
	121	if (!meth)
	122	return 1;
43ae5eed MC	123
	124	/* Check if extension is defined for our protocol. If not, skip */
	125	if (!extension_is_relevant(s, meth->context, context))
	126	return 1;
	127
	128	if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
	129	\| SSL_EXT_TLS1_3_SERVER_HELLO
	130	\| SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
0f113f3e	131	/*
43ae5eed MC	132	* If it's ServerHello or EncryptedExtensions we can't have any
43ae5eed MC	133	* extensions not sent in ClientHello.
0f113f3e	134	*/
43ae5eed	135	if ((meth->ext_flags & SSL_EXT_FLAG_SENT) == 0) {
0f113f3e MC	136	*al = TLS1_AD_UNSUPPORTED_EXTENSION;
	137	return 0;
	138	}
	139	}
43ae5eed MC	140
	141	/*
	142	* Extensions received in the ClientHello are marked with the
	143	* SSL_EXT_FLAG_RECEIVED. This is so we know to add the equivalent
	144	* extensions in the ServerHello/EncryptedExtensions message
	145	*/
	146	if ((context & SSL_EXT_CLIENT_HELLO) != 0)
	147	meth->ext_flags \|= SSL_EXT_FLAG_RECEIVED;
	148
0f113f3e MC	149	/* If no parse function set return success */
	150	if (!meth->parse_cb)
	151	return 1;
ecf4d660	152
43ae5eed MC	153	return meth->parse_cb(s, ext_type, context, ext_data, ext_size, x, chainidx,
43ae5eed MC	154	al, meth->parse_arg);
0f113f3e	155	}
ecf4d660	156
2c7b4dbc MC	157	/*
	158	* Request custom extension data from the application and add to the return
	159	* buffer.
	160	*/
43ae5eed MC	161	int custom_ext_add(SSL s, int context, WPACKET pkt, X509 *x, size_t chainidx,
43ae5eed MC	162	int maxversion, int *al)
2c7b4dbc	163	{
43ae5eed	164	custom_ext_methods *exts = &s->cert->custext;
2c7b4dbc MC	165	custom_ext_method *meth;
	166	size_t i;
	167
	168	for (i = 0; i < exts->meths_count; i++) {
	169	const unsigned char *out = NULL;
	170	size_t outlen = 0;
2c7b4dbc MC	171
	172	meth = exts->meths + i;
	173
43ae5eed MC	174	if (!should_add_extension(s, meth->context, context, maxversion))
	175	continue;
	176
	177	if ((context & (SSL_EXT_TLS1_2_SERVER_HELLO
	178	\| SSL_EXT_TLS1_3_SERVER_HELLO
	179	\| SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS)) != 0) {
2c7b4dbc	180	/*
43ae5eed MC	181	* For ServerHello/EncryptedExtensions only send extensions present
43ae5eed MC	182	* in ClientHello.
2c7b4dbc MC	183	*/
	184	if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
	185	continue;
2c7b4dbc	186	}
43ae5eed MC	187	/*
	188	* We skip it if the callback is absent - except for a ClientHello where
	189	* we add an empty extension.
	190	*/
	191	if ((context & SSL_EXT_CLIENT_HELLO) == 0 && meth->add_cb == NULL)
	192	continue;
	193
	194	if (meth->add_cb != NULL) {
2c7b4dbc	195	int cb_retval = 0;
43ae5eed MC	196	cb_retval = meth->add_cb(s, meth->ext_type, context, &out, &outlen,
43ae5eed MC	197	x, chainidx, al, meth->add_arg);
2c7b4dbc MC	198	if (cb_retval < 0)
	199	return 0; /* error */
	200	if (cb_retval == 0)
	201	continue; /* skip this extension */
	202	}
	203
08029dfa	204	if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
de451856	205	\|\| !WPACKET_start_sub_packet_u16(pkt)
0217dd19 MC	206	\|\| (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
0217dd19 MC	207	\|\| !WPACKET_close(pkt)) {
2c7b4dbc MC	208	*al = SSL_AD_INTERNAL_ERROR;
	209	return 0;
	210	}
43ae5eed MC	211	if ((context & SSL_EXT_CLIENT_HELLO) != 0) {
	212	/*
	213	* We can't send duplicates: code logic should prevent this.
	214	*/
	215	assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
	216	/*
	217	* Indicate extension has been sent: this is both a sanity check to
	218	* ensure we don't send duplicate extensions and indicates that it
	219	* is not an error if the extension is present in ServerHello.
	220	*/
	221	meth->ext_flags \|= SSL_EXT_FLAG_SENT;
	222	}
2c7b4dbc	223	if (meth->free_cb)
43ae5eed	224	meth->free_cb(s, meth->ext_type, context, out, meth->add_arg);
2c7b4dbc MC	225	}
	226	return 1;
	227	}
	228
ecf4d660	229	/* Copy table of custom extensions */
ecf4d660	230	int custom_exts_copy(custom_ext_methods dst, const custom_ext_methods src)
0f113f3e	231	{
43ae5eed MC	232	size_t i;
	233	int err = 0;
	234
	235	if (src->meths_count > 0) {
0f113f3e	236	dst->meths =
7644a9ae	237	OPENSSL_memdup(src->meths,
a230b26e	238	sizeof(custom_ext_method) * src->meths_count);
0f113f3e MC	239	if (dst->meths == NULL)
	240	return 0;
	241	dst->meths_count = src->meths_count;
43ae5eed MC	242
	243	for (i = 0; i < src->meths_count; i++) {
	244	custom_ext_method *methsrc = src->meths + i;
	245	custom_ext_method *methdst = dst->meths + i;
	246
	247	if (methsrc->add_cb != custom_ext_add_old_cb_wrap)
	248	continue;
	249
	250	/*
	251	* We have found an old style API wrapper. We need to copy the
	252	* arguments too.
	253	*/
	254
	255	if (err) {
	256	methdst->add_arg = NULL;
	257	methdst->parse_arg = NULL;
	258	continue;
	259	}
	260
	261	methdst->add_arg = OPENSSL_memdup(methsrc->add_arg,
	262	sizeof(custom_ext_add_cb_wrap));
	263	methdst->parse_arg = OPENSSL_memdup(methsrc->parse_arg,
	264	sizeof(custom_ext_parse_cb_wrap));
	265
	266	if (methdst->add_arg == NULL \|\| methdst->parse_arg == NULL)
	267	err = 1;
	268	}
	269	}
	270
	271	if (err) {
	272	custom_exts_free(dst);
	273	return 0;
0f113f3e	274	}
43ae5eed	275
0f113f3e MC	276	return 1;
0f113f3e MC	277	}
ecf4d660 DSH	278
ecf4d660 DSH	279	void custom_exts_free(custom_ext_methods *exts)
0f113f3e	280	{
43ae5eed MC	281	size_t i;
	282
	283	for (i = 0; i < exts->meths_count; i++) {
	284	custom_ext_method *meth = exts->meths + i;
	285
	286	if (meth->add_cb != custom_ext_add_old_cb_wrap)
	287	continue;
	288
	289	/* Old style API wrapper. Need to free the arguments too */
	290	OPENSSL_free(meth->add_arg);
	291	OPENSSL_free(meth->parse_arg);
	292	}
b548a1f1	293	OPENSSL_free(exts->meths);
0f113f3e	294	}
ecf4d660	295
43ae5eed MC	296	/* Return true if a client custom extension exists, false otherwise */
43ae5eed MC	297	int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
0f113f3e	298	{
43ae5eed MC	299	return custom_ext_find(&ctx->cert->custext, 0, ext_type, NULL) != NULL;
	300	}
	301
	302	static int add_custom_ext_intern(SSL_CTX *ctx, int server,
	303	unsigned int ext_type,
	304	unsigned int context,
	305	custom_ext_add_cb_ex add_cb,
	306	custom_ext_free_cb_ex free_cb,
	307	void *add_arg,
	308	custom_ext_parse_cb_ex parse_cb,
	309	void *parse_arg)
	310	{
	311	custom_ext_methods *exts = &ctx->cert->custext;
7c0ef843	312	custom_ext_method meth, tmp;
43ae5eed	313
0f113f3e MC	314	/*
	315	* Check application error: if add_cb is not set free_cb will never be
	316	* called.
	317	*/
	318	if (!add_cb && free_cb)
	319	return 0;
43ae5eed MC	320
	321	#ifndef OPENSSL_NO_CT
	322	/*
	323	* We don't want applications registering callbacks for SCT extensions
	324	* whilst simultaneously using the built-in SCT validation features, as
	325	* these two things may not play well together.
	326	*/
	327	if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp
	328	&& (context & SSL_EXT_CLIENT_HELLO) != 0
	329	&& SSL_CTX_ct_is_enabled(ctx))
	330	return 0;
	331	#endif
	332
ed29e82a RP	333	/*
	334	* Don't add if extension supported internally, but make exception
	335	* for extension types that previously were not supported, but now are.
	336	*/
43ae5eed MC	337	if (SSL_extension_supported(ext_type)
43ae5eed MC	338	&& ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
0f113f3e	339	return 0;
43ae5eed	340
0f113f3e MC	341	/* Extension type must fit in 16 bits */
	342	if (ext_type > 0xffff)
	343	return 0;
	344	/* Search for duplicate */
43ae5eed	345	if (custom_ext_find(exts, server, ext_type, NULL))
0f113f3e	346	return 0;
7c0ef843 DSH	347	tmp = OPENSSL_realloc(exts->meths,
7c0ef843 DSH	348	(exts->meths_count + 1) * sizeof(custom_ext_method));
ecf4d660	349
ed874fac	350	if (tmp == NULL)
0f113f3e	351	return 0;
ecf4d660	352
7c0ef843	353	exts->meths = tmp;
0f113f3e	354	meth = exts->meths + exts->meths_count;
16f8d4eb	355	memset(meth, 0, sizeof(*meth));
43ae5eed MC	356	meth->server = server;
43ae5eed MC	357	meth->context = context;
0f113f3e MC	358	meth->parse_cb = parse_cb;
	359	meth->add_cb = add_cb;
	360	meth->free_cb = free_cb;
	361	meth->ext_type = ext_type;
	362	meth->add_arg = add_arg;
	363	meth->parse_arg = parse_arg;
	364	exts->meths_count++;
	365	return 1;
	366	}
ecf4d660	367
43ae5eed MC	368	static int add_old_custom_ext(SSL_CTX *ctx, int server, unsigned int ext_type,
	369	unsigned int context,
	370	custom_ext_add_cb add_cb,
	371	custom_ext_free_cb free_cb,
	372	void *add_arg,
	373	custom_ext_parse_cb parse_cb, void *parse_arg)
ed29e82a	374	{
43ae5eed MC	375	custom_ext_add_cb_wrap *add_cb_wrap
	376	= OPENSSL_malloc(sizeof(custom_ext_add_cb_wrap));
	377	custom_ext_parse_cb_wrap *parse_cb_wrap
	378	= OPENSSL_malloc(sizeof(custom_ext_parse_cb_wrap));
	379	int ret;
	380
	381	if (add_cb_wrap == NULL \|\| parse_cb_wrap == NULL) {
	382	OPENSSL_free(add_cb_wrap);
	383	OPENSSL_free(parse_cb_wrap);
	384	return 0;
	385	}
	386
	387	add_cb_wrap->add_arg = add_arg;
	388	add_cb_wrap->add_cb = add_cb;
	389	add_cb_wrap->free_cb = free_cb;
	390	parse_cb_wrap->parse_arg = parse_arg;
	391	parse_cb_wrap->parse_cb = parse_cb;
	392
	393	/*
	394	* TODO(TLS1.3): Is it possible with the old API to add custom exts for both
	395	* client and server for the same type in the same SSL_CTX? We don't handle
	396	* that yet.
	397	*/
	398	ret = add_custom_ext_intern(ctx, server, ext_type,
	399	context,
	400	custom_ext_add_old_cb_wrap,
	401	custom_ext_free_old_cb_wrap,
	402	add_cb_wrap,
	403	custom_ext_parse_old_cb_wrap,
	404	parse_cb_wrap);
	405
	406	if (!ret) {
	407	OPENSSL_free(add_cb_wrap);
	408	OPENSSL_free(parse_cb_wrap);
	409	}
	410
	411	return ret;
ed29e82a RP	412	}
ed29e82a RP	413
43ae5eed	414	/* Application level functions to add the old custom extension callbacks */
8cafe9e8	415	int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
0f113f3e MC	416	custom_ext_add_cb add_cb,
0f113f3e MC	417	custom_ext_free_cb free_cb,
0cfefe4b	418	void *add_arg,
a230b26e	419	custom_ext_parse_cb parse_cb, void *parse_arg)
0f113f3e	420	{
43ae5eed MC	421	return add_old_custom_ext(ctx, 0, ext_type,
	422	SSL_EXT_TLS1_2_AND_BELOW_ONLY
	423	\| SSL_EXT_CLIENT_HELLO
	424	\| SSL_EXT_TLS1_2_SERVER_HELLO
	425	\| SSL_EXT_IGNORE_ON_RESUMPTION,
	426	add_cb, free_cb, add_arg, parse_cb, parse_arg);
0f113f3e	427	}
ecf4d660	428
8cafe9e8	429	int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
0f113f3e MC	430	custom_ext_add_cb add_cb,
0f113f3e MC	431	custom_ext_free_cb free_cb,
0cfefe4b	432	void *add_arg,
a230b26e	433	custom_ext_parse_cb parse_cb, void *parse_arg)
0f113f3e	434	{
43ae5eed MC	435	return add_old_custom_ext(ctx, 1, ext_type,
	436	SSL_EXT_TLS1_2_AND_BELOW_ONLY
	437	\| SSL_EXT_CLIENT_HELLO
	438	\| SSL_EXT_TLS1_2_SERVER_HELLO
	439	\| SSL_EXT_IGNORE_ON_RESUMPTION,
	440	add_cb, free_cb, add_arg, parse_cb, parse_arg);
	441	}
	442
	443	int SSL_CTX_add_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
	444	unsigned int context,
	445	custom_ext_add_cb_ex add_cb,
	446	custom_ext_free_cb_ex free_cb,
	447	void *add_arg,
	448	custom_ext_parse_cb_ex parse_cb, void *parse_arg)
	449	{
	450	return add_custom_ext_intern(ctx, -1, ext_type, context, add_cb, free_cb,
	451	add_arg, parse_cb, parse_arg);
0f113f3e	452	}
c846a5f5 DSH	453
c846a5f5 DSH	454	int SSL_extension_supported(unsigned int ext_type)
0f113f3e MC	455	{
	456	switch (ext_type) {
	457	/* Internally supported extensions. */
	458	case TLSEXT_TYPE_application_layer_protocol_negotiation:
36abb6a2	459	#ifndef OPENSSL_NO_EC
0f113f3e	460	case TLSEXT_TYPE_ec_point_formats:
de4d764e	461	case TLSEXT_TYPE_supported_groups:
36abb6a2 MC	462	case TLSEXT_TYPE_key_share:
36abb6a2 MC	463	#endif
1595ca02	464	#ifndef OPENSSL_NO_NEXTPROTONEG
0f113f3e	465	case TLSEXT_TYPE_next_proto_neg:
1595ca02	466	#endif
0f113f3e MC	467	case TLSEXT_TYPE_padding:
	468	case TLSEXT_TYPE_renegotiate:
	469	case TLSEXT_TYPE_server_name:
	470	case TLSEXT_TYPE_session_ticket:
	471	case TLSEXT_TYPE_signature_algorithms:
36abb6a2	472	#ifndef OPENSSL_NO_SRP
0f113f3e	473	case TLSEXT_TYPE_srp:
36abb6a2 MC	474	#endif
36abb6a2 MC	475	#ifndef OPENSSL_NO_OCSP
0f113f3e	476	case TLSEXT_TYPE_status_request:
36abb6a2 MC	477	#endif
36abb6a2 MC	478	#ifndef OPENSSL_NO_CT
ed29e82a	479	case TLSEXT_TYPE_signed_certificate_timestamp:
36abb6a2 MC	480	#endif
36abb6a2 MC	481	#ifndef OPENSSL_NO_SRTP
0f113f3e	482	case TLSEXT_TYPE_use_srtp:
e481f9b9	483	#endif
36abb6a2	484	case TLSEXT_TYPE_encrypt_then_mac:
91b60e2a MC	485	case TLSEXT_TYPE_supported_versions:
91b60e2a MC	486	case TLSEXT_TYPE_extended_master_secret:
36abb6a2 MC	487	case TLSEXT_TYPE_psk_kex_modes:
	488	case TLSEXT_TYPE_cookie:
	489	case TLSEXT_TYPE_early_data:
	490	case TLSEXT_TYPE_certificate_authorities:
	491	case TLSEXT_TYPE_psk:
0f113f3e MC	492	return 1;
	493	default:
	494	return 0;
	495	}
	496	}