| /* Copyright (c) 2014, Google Inc. |
| * |
| * Permission to use, copy, modify, and/or 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 <openssl/ssl.h> |
| |
| #include <assert.h> |
| #include <string.h> |
| |
| #include <openssl/bytestring.h> |
| #include <openssl/err.h> |
| #include <openssl/mem.h> |
| #include <openssl/stack.h> |
| |
| #include "internal.h" |
| |
| |
| void SSL_CUSTOM_EXTENSION_free(SSL_CUSTOM_EXTENSION *custom_extension) { |
| OPENSSL_free(custom_extension); |
| } |
| |
| static const SSL_CUSTOM_EXTENSION *custom_ext_find( |
| STACK_OF(SSL_CUSTOM_EXTENSION) *stack, |
| unsigned *out_index, uint16_t value) { |
| for (size_t i = 0; i < sk_SSL_CUSTOM_EXTENSION_num(stack); i++) { |
| const SSL_CUSTOM_EXTENSION *ext = sk_SSL_CUSTOM_EXTENSION_value(stack, i); |
| if (ext->value == value) { |
| if (out_index != NULL) { |
| *out_index = i; |
| } |
| return ext; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /* default_add_callback is used as the |add_callback| when the user doesn't |
| * provide one. For servers, it does nothing while, for clients, it causes an |
| * empty extension to be included. */ |
| static int default_add_callback(SSL *ssl, unsigned extension_value, |
| const uint8_t **out, size_t *out_len, |
| int *out_alert_value, void *add_arg) { |
| if (ssl->server) { |
| return 0; |
| } |
| *out_len = 0; |
| return 1; |
| } |
| |
| static int custom_ext_add_hello(SSL_HANDSHAKE *hs, CBB *extensions) { |
| SSL *const ssl = hs->ssl; |
| STACK_OF(SSL_CUSTOM_EXTENSION) *stack = ssl->ctx->client_custom_extensions; |
| if (ssl->server) { |
| stack = ssl->ctx->server_custom_extensions; |
| } |
| |
| if (stack == NULL) { |
| return 1; |
| } |
| |
| if (ssl->cert->enable_early_data) { |
| /* TODO(svaldez): Support Custom Extensions with 0-RTT. For now the caller |
| * is expected not to configure both together. |
| * https://crbug.com/boringssl/173. */ |
| OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR); |
| return 0; |
| } |
| |
| for (size_t i = 0; i < sk_SSL_CUSTOM_EXTENSION_num(stack); i++) { |
| const SSL_CUSTOM_EXTENSION *ext = sk_SSL_CUSTOM_EXTENSION_value(stack, i); |
| |
| if (ssl->server && |
| !(hs->custom_extensions.received & (1u << i))) { |
| /* Servers cannot echo extensions that the client didn't send. */ |
| continue; |
| } |
| |
| const uint8_t *contents; |
| size_t contents_len; |
| int alert = SSL_AD_DECODE_ERROR; |
| CBB contents_cbb; |
| |
| switch (ext->add_callback(ssl, ext->value, &contents, &contents_len, &alert, |
| ext->add_arg)) { |
| case 1: |
| if (!CBB_add_u16(extensions, ext->value) || |
| !CBB_add_u16_length_prefixed(extensions, &contents_cbb) || |
| !CBB_add_bytes(&contents_cbb, contents, contents_len) || |
| !CBB_flush(extensions)) { |
| OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR); |
| ERR_add_error_dataf("extension %u", (unsigned) ext->value); |
| if (ext->free_callback && 0 < contents_len) { |
| ext->free_callback(ssl, ext->value, contents, ext->add_arg); |
| } |
| return 0; |
| } |
| |
| if (ext->free_callback && 0 < contents_len) { |
| ext->free_callback(ssl, ext->value, contents, ext->add_arg); |
| } |
| |
| if (!ssl->server) { |
| assert((hs->custom_extensions.sent & (1u << i)) == 0); |
| hs->custom_extensions.sent |= (1u << i); |
| } |
| break; |
| |
| case 0: |
| break; |
| |
| default: |
| ssl3_send_alert(ssl, SSL3_AL_FATAL, alert); |
| OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR); |
| ERR_add_error_dataf("extension %u", (unsigned) ext->value); |
| return 0; |
| } |
| } |
| |
| return 1; |
| } |
| |
| int custom_ext_add_clienthello(SSL_HANDSHAKE *hs, CBB *extensions) { |
| return custom_ext_add_hello(hs, extensions); |
| } |
| |
| int custom_ext_parse_serverhello(SSL_HANDSHAKE *hs, int *out_alert, |
| uint16_t value, const CBS *extension) { |
| SSL *const ssl = hs->ssl; |
| unsigned index; |
| const SSL_CUSTOM_EXTENSION *ext = |
| custom_ext_find(ssl->ctx->client_custom_extensions, &index, value); |
| |
| if (/* Unknown extensions are not allowed in a ServerHello. */ |
| ext == NULL || |
| /* Also, if we didn't send the extension, that's also unacceptable. */ |
| !(hs->custom_extensions.sent & (1u << index))) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_UNEXPECTED_EXTENSION); |
| ERR_add_error_dataf("extension %u", (unsigned)value); |
| *out_alert = SSL_AD_UNSUPPORTED_EXTENSION; |
| return 0; |
| } |
| |
| if (ext->parse_callback != NULL && |
| !ext->parse_callback(ssl, value, CBS_data(extension), CBS_len(extension), |
| out_alert, ext->parse_arg)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR); |
| ERR_add_error_dataf("extension %u", (unsigned)ext->value); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| int custom_ext_parse_clienthello(SSL_HANDSHAKE *hs, int *out_alert, |
| uint16_t value, const CBS *extension) { |
| SSL *const ssl = hs->ssl; |
| unsigned index; |
| const SSL_CUSTOM_EXTENSION *ext = |
| custom_ext_find(ssl->ctx->server_custom_extensions, &index, value); |
| |
| if (ext == NULL) { |
| return 1; |
| } |
| |
| assert((hs->custom_extensions.received & (1u << index)) == 0); |
| hs->custom_extensions.received |= (1u << index); |
| |
| if (ext->parse_callback && |
| !ext->parse_callback(ssl, value, CBS_data(extension), CBS_len(extension), |
| out_alert, ext->parse_arg)) { |
| OPENSSL_PUT_ERROR(SSL, SSL_R_CUSTOM_EXTENSION_ERROR); |
| ERR_add_error_dataf("extension %u", (unsigned)ext->value); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| int custom_ext_add_serverhello(SSL_HANDSHAKE *hs, CBB *extensions) { |
| return custom_ext_add_hello(hs, extensions); |
| } |
| |
| /* MAX_NUM_CUSTOM_EXTENSIONS is the maximum number of custom extensions that |
| * can be set on an |SSL_CTX|. It's determined by the size of the bitset used |
| * to track when an extension has been sent. */ |
| #define MAX_NUM_CUSTOM_EXTENSIONS \ |
| (sizeof(((SSL_HANDSHAKE *)NULL)->custom_extensions.sent) * 8) |
| |
| static int custom_ext_append(STACK_OF(SSL_CUSTOM_EXTENSION) **stack, |
| unsigned extension_value, |
| SSL_custom_ext_add_cb add_cb, |
| SSL_custom_ext_free_cb free_cb, void *add_arg, |
| SSL_custom_ext_parse_cb parse_cb, |
| void *parse_arg) { |
| if (add_cb == NULL || |
| 0xffff < extension_value || |
| SSL_extension_supported(extension_value) || |
| /* Specifying a free callback without an add callback is nonsensical |
| * and an error. */ |
| (*stack != NULL && |
| (MAX_NUM_CUSTOM_EXTENSIONS <= sk_SSL_CUSTOM_EXTENSION_num(*stack) || |
| custom_ext_find(*stack, NULL, extension_value) != NULL))) { |
| return 0; |
| } |
| |
| SSL_CUSTOM_EXTENSION *ext = OPENSSL_malloc(sizeof(SSL_CUSTOM_EXTENSION)); |
| if (ext == NULL) { |
| return 0; |
| } |
| ext->add_callback = add_cb; |
| ext->add_arg = add_arg; |
| ext->free_callback = free_cb; |
| ext->parse_callback = parse_cb; |
| ext->parse_arg = parse_arg; |
| ext->value = extension_value; |
| |
| if (*stack == NULL) { |
| *stack = sk_SSL_CUSTOM_EXTENSION_new_null(); |
| if (*stack == NULL) { |
| SSL_CUSTOM_EXTENSION_free(ext); |
| return 0; |
| } |
| } |
| |
| if (!sk_SSL_CUSTOM_EXTENSION_push(*stack, ext)) { |
| SSL_CUSTOM_EXTENSION_free(ext); |
| if (sk_SSL_CUSTOM_EXTENSION_num(*stack) == 0) { |
| sk_SSL_CUSTOM_EXTENSION_free(*stack); |
| *stack = NULL; |
| } |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned extension_value, |
| SSL_custom_ext_add_cb add_cb, |
| SSL_custom_ext_free_cb free_cb, void *add_arg, |
| SSL_custom_ext_parse_cb parse_cb, |
| void *parse_arg) { |
| return custom_ext_append(&ctx->client_custom_extensions, extension_value, |
| add_cb ? add_cb : default_add_callback, free_cb, |
| add_arg, parse_cb, parse_arg); |
| } |
| |
| int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned extension_value, |
| SSL_custom_ext_add_cb add_cb, |
| SSL_custom_ext_free_cb free_cb, void *add_arg, |
| SSL_custom_ext_parse_cb parse_cb, |
| void *parse_arg) { |
| return custom_ext_append(&ctx->server_custom_extensions, extension_value, |
| add_cb ? add_cb : default_add_callback, free_cb, |
| add_arg, parse_cb, parse_arg); |
| } |