ustream-openssl.c

   1 /*
   2  * ustream-ssl - library for SSL over ustream
   3  *
   4  * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <string.h>
  20 #include <ctype.h>
  21 #include "ustream-ssl.h"
  22 #include "ustream-internal.h"
  23
  24 #if !defined(HAVE_WOLFSSL)
  25 #include <openssl/x509v3.h>
  26 #endif
  27
  28 /* Ciphersuite preference:
  29  * - for server, no weak ciphers are used if you use an ECDSA key.
  30  * - forward-secret (pfs), authenticated (AEAD) ciphers are at the top:
  31  *      chacha20-poly1305, the fastest in software, 256-bits
  32  *      aes128-gcm, 128-bits
  33  *      aes256-gcm, 256-bits
  34  * - key exchange: prefer ECDHE, then DHE (client only)
  35  * - forward-secret ECDSA CBC ciphers (client-only)
  36  * - forward-secret RSA CBC ciphers
  37  * - non-pfs ciphers
  38  *      aes128, aes256, 3DES(client only)
  39  */
  40
  41 #ifdef WOLFSSL_SSL_H
  42 # define top_ciphers                                                    \
  43                                 "TLS13-CHACHA20-POLY1305-SHA256:"       \
  44                                 "TLS13-AES128-GCM-SHA256:"              \
  45                                 "TLS13-AES256-GCM-SHA384:"              \
  46                                 ecdhe_aead_ciphers
  47 #else
  48 # define tls13_ciphersuites     "TLS_CHACHA20_POLY1305_SHA256:"         \
  49                                 "TLS_AES_128_GCM_SHA256:"               \
  50                                 "TLS_AES_256_GCM_SHA384"
  51
  52 # define top_ciphers                                                    \
  53                                 ecdhe_aead_ciphers
  54 #endif
  55
  56 #define ecdhe_aead_ciphers                                              \
  57                                 "ECDHE-ECDSA-CHACHA20-POLY1305:"        \
  58                                 "ECDHE-ECDSA-AES128-GCM-SHA256:"        \
  59                                 "ECDHE-ECDSA-AES256-GCM-SHA384:"        \
  60                                 "ECDHE-RSA-CHACHA20-POLY1305:"          \
  61                                 "ECDHE-RSA-AES128-GCM-SHA256:"          \
  62                                 "ECDHE-RSA-AES256-GCM-SHA384"
  63
  64 #define dhe_aead_ciphers                                                \
  65                                 "DHE-RSA-CHACHA20-POLY1305:"            \
  66                                 "DHE-RSA-AES128-GCM-SHA256:"            \
  67                                 "DHE-RSA-AES256-GCM-SHA384"
  68
  69 #define ecdhe_ecdsa_cbc_ciphers                                         \
  70                                 "ECDHE-ECDSA-AES128-SHA:"               \
  71                                 "ECDHE-ECDSA-AES256-SHA"
  72
  73 #define ecdhe_rsa_cbc_ciphers                                           \
  74                                 "ECDHE-RSA-AES128-SHA:"                 \
  75                                 "ECDHE-RSA-AES256-SHA"
  76
  77 #define dhe_cbc_ciphers                                                 \
  78                                 "DHE-RSA-AES128-SHA:"                   \
  79                                 "DHE-RSA-AES256-SHA:"                   \
  80                                 "DHE-DES-CBC3-SHA"
  81
  82 #define non_pfs_aes                                                     \
  83                                 "AES128-GCM-SHA256:"                    \
  84                                 "AES256-GCM-SHA384:"                    \
  85                                 "AES128-SHA:"                           \
  86                                 "AES256-SHA"
  87
  88 #define server_cipher_list                                              \
  89                                 top_ciphers ":"                         \
  90                                 ecdhe_rsa_cbc_ciphers ":"               \
  91                                 non_pfs_aes
  92
  93 #define client_cipher_list                                              \
  94                                 top_ciphers ":"                         \
  95                                 dhe_aead_ciphers ":"                    \
  96                                 ecdhe_ecdsa_cbc_ciphers ":"             \
  97                                 ecdhe_rsa_cbc_ciphers ":"               \
  98                                 dhe_cbc_ciphers ":"                     \
  99                                 non_pfs_aes ":"                         \
 100                                 "DES-CBC3-SHA"
 101
 102 __hidden struct ustream_ssl_ctx *
 103 __ustream_ssl_context_new(bool server)
 104 {
 105         const void *m;
 106         SSL_CTX *c;
 107
 108 #if OPENSSL_VERSION_NUMBER < 0x10100000L
 109         static bool _init = false;
 110
 111         if (!_init) {
 112                 SSL_load_error_strings();
 113                 SSL_library_init();
 114                 _init = true;
 115         }
 116 # ifndef TLS_server_method
 117 #  define TLS_server_method SSLv23_server_method
 118 # endif
 119 # ifndef TLS_client_method
 120 #  define TLS_client_method SSLv23_client_method
 121 # endif
 122 #endif
 123
 124         if (server) {
 125                 m = TLS_server_method();
 126         } else
 127                 m = TLS_client_method();
 128
 129         c = SSL_CTX_new((void *) m);
 130         if (!c)
 131                 return NULL;
 132
 133         SSL_CTX_set_verify(c, SSL_VERIFY_NONE, NULL);
 134         SSL_CTX_set_options(c, SSL_OP_NO_COMPRESSION | SSL_OP_SINGLE_ECDH_USE |
 135                                SSL_OP_CIPHER_SERVER_PREFERENCE);
 136 #if defined(SSL_CTX_set_ecdh_auto) && OPENSSL_VERSION_NUMBER < 0x10100000L
 137         SSL_CTX_set_ecdh_auto(c, 1);
 138 #elif OPENSSL_VERSION_NUMBER >= 0x10101000L
 139         SSL_CTX_set_ciphersuites(c, tls13_ciphersuites);
 140 #endif
 141         if (server) {
 142 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
 143                 SSL_CTX_set_min_proto_version(c, TLS1_2_VERSION);
 144 #else
 145                 SSL_CTX_set_options(c, SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1 |
 146                                        SSL_OP_NO_TLSv1_1);
 147 #endif
 148                 SSL_CTX_set_cipher_list(c, server_cipher_list);
 149         } else {
 150                 SSL_CTX_set_cipher_list(c, client_cipher_list);
 151         }
 152         SSL_CTX_set_quiet_shutdown(c, 1);
 153
 154         return (void *) c;
 155 }
 156
 157 __hidden int __ustream_ssl_add_ca_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 158 {
 159         int ret;
 160
 161         ret = SSL_CTX_load_verify_locations((void *) ctx, file, NULL);
 162         if (ret < 1)
 163                 return -1;
 164
 165         return 0;
 166 }
 167
 168 __hidden int __ustream_ssl_set_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 169 {
 170         int ret;
 171
 172         ret = SSL_CTX_use_certificate_chain_file((void *) ctx, file);
 173         if (ret < 1)
 174                 ret = SSL_CTX_use_certificate_file((void *) ctx, file, SSL_FILETYPE_ASN1);
 175
 176         if (ret < 1)
 177                 return -1;
 178
 179         return 0;
 180 }
 181
 182 __hidden int __ustream_ssl_set_key_file(struct ustream_ssl_ctx *ctx, const char *file)
 183 {
 184         int ret;
 185
 186         ret = SSL_CTX_use_PrivateKey_file((void *) ctx, file, SSL_FILETYPE_PEM);
 187         if (ret < 1)
 188                 ret = SSL_CTX_use_PrivateKey_file((void *) ctx, file, SSL_FILETYPE_ASN1);
 189
 190         if (ret < 1)
 191                 return -1;
 192
 193         return 0;
 194 }
 195
 196 __hidden int __ustream_ssl_set_ciphers(struct ustream_ssl_ctx *ctx, const char *ciphers)
 197 {
 198         int ret = SSL_CTX_set_cipher_list((void *) ctx, ciphers);
 199
 200         if (ret == 0)
 201                 return -1;
 202
 203         return 0;
 204 }
 205
 206 __hidden void __ustream_ssl_context_free(struct ustream_ssl_ctx *ctx)
 207 {
 208         SSL_CTX_free((void *) ctx);
 209 }
 210
 211 void __ustream_ssl_session_free(void *ssl)
 212 {
 213         BIO *bio = SSL_get_wbio(ssl);
 214         struct bio_ctx *ctx = BIO_get_data(bio);
 215
 216         SSL_shutdown(ssl);
 217         SSL_free(ssl);
 218         if (ctx) {
 219                 BIO_meth_free(ctx->meth);
 220                 free(ctx);
 221         }
 222 }
 223
 224 static void ustream_ssl_error(struct ustream_ssl *us, int ret)
 225 {
 226         us->error = ret;
 227         uloop_timeout_set(&us->error_timer, 0);
 228 }
 229
 230 #ifndef NO_X509_CHECK_HOST
 231
 232 static bool ustream_ssl_verify_cn(struct ustream_ssl *us, X509 *cert)
 233 {
 234         int ret;
 235
 236         if (!us->peer_cn)
 237                 return false;
 238
 239 # ifndef WOLFSSL_OPENSSL_H_
 240         ret = X509_check_host(cert, us->peer_cn, 0, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS, NULL);
 241 # else
 242         ret = wolfSSL_X509_check_host(cert, us->peer_cn, 0, 0, NULL);
 243 # endif
 244         return ret == 1;
 245 }
 246
 247 #endif
 248
 249 static void ustream_ssl_verify_cert(struct ustream_ssl *us)
 250 {
 251         void *ssl = us->ssl;
 252         X509 *cert;
 253         int res;
 254
 255         res = SSL_get_verify_result(ssl);
 256         if (res != X509_V_OK) {
 257                 if (us->notify_verify_error)
 258                         us->notify_verify_error(us, res, X509_verify_cert_error_string(res));
 259                 return;
 260         }
 261
 262         cert = SSL_get_peer_certificate(ssl);
 263         if (!cert)
 264                 return;
 265
 266         us->valid_cert = true;
 267 #ifndef NO_X509_CHECK_HOST
 268         us->valid_cn = ustream_ssl_verify_cn(us, cert);
 269 #endif
 270         X509_free(cert);
 271 }
 272
 273
 274 __hidden enum ssl_conn_status __ustream_ssl_connect(struct ustream_ssl *us)
 275 {
 276         void *ssl = us->ssl;
 277         int r;
 278
 279         ERR_clear_error();
 280
 281         if (us->server)
 282                 r = SSL_accept(ssl);
 283         else
 284                 r = SSL_connect(ssl);
 285
 286         if (r == 1) {
 287                 ustream_ssl_verify_cert(us);
 288                 return U_SSL_OK;
 289         }
 290
 291         r = SSL_get_error(ssl, r);
 292         if (r == SSL_ERROR_WANT_READ || r == SSL_ERROR_WANT_WRITE)
 293                 return U_SSL_PENDING;
 294
 295         ustream_ssl_error(us, r);
 296         return U_SSL_ERROR;
 297 }
 298
 299 __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int len)
 300 {
 301         void *ssl = us->ssl;
 302         int ret;
 303
 304         ERR_clear_error();
 305
 306         ret = SSL_write(ssl, buf, len);
 307
 308         if (ret < 0) {
 309                 int err = SSL_get_error(ssl, ret);
 310                 if (err == SSL_ERROR_WANT_WRITE)
 311                         return 0;
 312
 313                 ustream_ssl_error(us, err);
 314                 return -1;
 315         }
 316
 317         return ret;
 318 }
 319
 320 __hidden int __ustream_ssl_read(struct ustream_ssl *us, char *buf, int len)
 321 {
 322         int ret;
 323
 324         ERR_clear_error();
 325
 326         ret = SSL_read(us->ssl, buf, len);
 327
 328         if (ret < 0) {
 329                 ret = SSL_get_error(us->ssl, ret);
 330                 if (ret == SSL_ERROR_WANT_READ)
 331                         return U_SSL_PENDING;
 332
 333                 ustream_ssl_error(us, ret);
 334                 return U_SSL_ERROR;
 335         }
 336
 337         return ret;
 338 }