2 * Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
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
10 /* Custom extension utility functions */
12 #include <openssl/ct.h>
15 /* Find a custom extension from the list. */
16 static custom_ext_method *custom_ext_find(const custom_ext_methods *exts,
17 unsigned int ext_type)
20 custom_ext_method *meth = exts->meths;
21 for (i = 0; i < exts->meths_count; i++, meth++) {
22 if (ext_type == meth->ext_type)
29 * Initialise custom extensions flags to indicate neither sent nor received.
31 void custom_ext_init(custom_ext_methods *exts)
34 custom_ext_method *meth = exts->meths;
35 for (i = 0; i < exts->meths_count; i++, meth++)
39 /* Pass received custom extension data to the application for parsing. */
40 int custom_ext_parse(SSL *s, int server,
41 unsigned int ext_type,
42 const unsigned char *ext_data, size_t ext_size, int *al)
44 custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
45 custom_ext_method *meth;
46 meth = custom_ext_find(exts, ext_type);
47 /* If not found return success */
52 * If it's ServerHello we can't have any extensions not sent in
55 if (!(meth->ext_flags & SSL_EXT_FLAG_SENT)) {
56 *al = TLS1_AD_UNSUPPORTED_EXTENSION;
60 /* If already present it's a duplicate */
61 if (meth->ext_flags & SSL_EXT_FLAG_RECEIVED) {
62 *al = TLS1_AD_DECODE_ERROR;
65 meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
66 /* If no parse function set return success */
70 return meth->parse_cb(s, ext_type, ext_data, ext_size, al, meth->parse_arg);
74 * Request custom extension data from the application and add to the return
77 int custom_ext_add(SSL *s, int server, WPACKET *pkt, int *al)
79 custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
80 custom_ext_method *meth;
83 for (i = 0; i < exts->meths_count; i++) {
84 const unsigned char *out = NULL;
87 meth = exts->meths + i;
91 * For ServerHello only send extensions present in ClientHello.
93 if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
95 /* If callback absent for server skip it */
101 cb_retval = meth->add_cb(s, meth->ext_type,
102 &out, &outlen, al, meth->add_arg);
104 return 0; /* error */
106 continue; /* skip this extension */
109 if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
110 || !WPACKET_start_sub_packet_u16(pkt)
111 || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
112 || !WPACKET_close(pkt)) {
113 *al = SSL_AD_INTERNAL_ERROR;
117 * We can't send duplicates: code logic should prevent this.
119 OPENSSL_assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
121 * Indicate extension has been sent: this is both a sanity check to
122 * ensure we don't send duplicate extensions and indicates that it is
123 * not an error if the extension is present in ServerHello.
125 meth->ext_flags |= SSL_EXT_FLAG_SENT;
127 meth->free_cb(s, meth->ext_type, out, meth->add_arg);
132 /* Copy table of custom extensions */
133 int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
135 if (src->meths_count) {
137 OPENSSL_memdup(src->meths,
138 sizeof(custom_ext_method) * src->meths_count);
139 if (dst->meths == NULL)
141 dst->meths_count = src->meths_count;
146 void custom_exts_free(custom_ext_methods *exts)
148 OPENSSL_free(exts->meths);
151 /* Set callbacks for a custom extension. */
152 static int custom_ext_meth_add(custom_ext_methods *exts,
153 unsigned int ext_type,
154 custom_ext_add_cb add_cb,
155 custom_ext_free_cb free_cb,
157 custom_ext_parse_cb parse_cb, void *parse_arg)
159 custom_ext_method *meth, *tmp;
161 * Check application error: if add_cb is not set free_cb will never be
164 if (!add_cb && free_cb)
167 * Don't add if extension supported internally, but make exception
168 * for extension types that previously were not supported, but now are.
170 if (SSL_extension_supported(ext_type) &&
171 ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
173 /* Extension type must fit in 16 bits */
174 if (ext_type > 0xffff)
176 /* Search for duplicate */
177 if (custom_ext_find(exts, ext_type))
179 tmp = OPENSSL_realloc(exts->meths,
180 (exts->meths_count + 1) * sizeof(custom_ext_method));
183 OPENSSL_free(exts->meths);
185 exts->meths_count = 0;
190 meth = exts->meths + exts->meths_count;
191 memset(meth, 0, sizeof(*meth));
192 meth->parse_cb = parse_cb;
193 meth->add_cb = add_cb;
194 meth->free_cb = free_cb;
195 meth->ext_type = ext_type;
196 meth->add_arg = add_arg;
197 meth->parse_arg = parse_arg;
202 /* Return true if a client custom extension exists, false otherwise */
203 int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
205 return custom_ext_find(&ctx->cert->cli_ext, ext_type) != NULL;
208 /* Application level functions to add custom extension callbacks */
209 int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
210 custom_ext_add_cb add_cb,
211 custom_ext_free_cb free_cb,
213 custom_ext_parse_cb parse_cb, void *parse_arg)
215 #ifndef OPENSSL_NO_CT
217 * We don't want applications registering callbacks for SCT extensions
218 * whilst simultaneously using the built-in SCT validation features, as
219 * these two things may not play well together.
221 if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp &&
222 SSL_CTX_ct_is_enabled(ctx))
225 return custom_ext_meth_add(&ctx->cert->cli_ext, ext_type, add_cb,
226 free_cb, add_arg, parse_cb, parse_arg);
229 int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
230 custom_ext_add_cb add_cb,
231 custom_ext_free_cb free_cb,
233 custom_ext_parse_cb parse_cb, void *parse_arg)
235 return custom_ext_meth_add(&ctx->cert->srv_ext, ext_type,
236 add_cb, free_cb, add_arg, parse_cb, parse_arg);
239 int SSL_extension_supported(unsigned int ext_type)
242 /* Internally supported extensions. */
243 case TLSEXT_TYPE_application_layer_protocol_negotiation:
244 case TLSEXT_TYPE_ec_point_formats:
245 case TLSEXT_TYPE_supported_groups:
246 #ifndef OPENSSL_NO_NEXTPROTONEG
247 case TLSEXT_TYPE_next_proto_neg:
249 case TLSEXT_TYPE_padding:
250 case TLSEXT_TYPE_renegotiate:
251 case TLSEXT_TYPE_server_name:
252 case TLSEXT_TYPE_session_ticket:
253 case TLSEXT_TYPE_signature_algorithms:
254 case TLSEXT_TYPE_srp:
255 case TLSEXT_TYPE_status_request:
256 case TLSEXT_TYPE_signed_certificate_timestamp:
257 case TLSEXT_TYPE_use_srtp:
258 #ifdef TLSEXT_TYPE_encrypt_then_mac
259 case TLSEXT_TYPE_encrypt_then_mac: