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 <sys/types.h> 20 #include <fcntl.h> 21 #include <unistd.h> 22 #include <stdlib.h> 23 #include <string.h> 24 25 #include "ustream-ssl.h" 26 #include "ustream-internal.h" 27 28 static int urandom_fd = -1; 29 30 static int s_ustream_read(void *ctx, unsigned char *buf, size_t len) 31 { 32 struct ustream *s = ctx; 33 char *sbuf; 34 int slen; 35 36 if (s->eof) 37 return 0; 38 39 sbuf = ustream_get_read_buf(s, &slen); 40 if (slen > len) 41 slen = len; 42 43 if (!slen) 44 return MBEDTLS_ERR_SSL_WANT_READ; 45 46 memcpy(buf, sbuf, slen); 47 ustream_consume(s, slen); 48 49 return slen; 50 } 51 52 static int s_ustream_write(void *ctx, const unsigned char *buf, size_t len) 53 { 54 struct ustream *s = ctx; 55 int ret; 56 57 ret = ustream_write(s, (const char *) buf, len, false); 58 if (ret < 0 || s->write_error) 59 return MBEDTLS_ERR_NET_SEND_FAILED; 60 61 return ret; 62 } 63 64 __hidden void ustream_set_io(struct ustream_ssl_ctx *ctx, void *ssl, struct ustream *conn) 65 { 66 mbedtls_ssl_set_bio(ssl, conn, s_ustream_write, s_ustream_read, NULL); 67 } 68 69 static bool urandom_init(void) 70 { 71 if (urandom_fd > -1) 72 return true; 73 74 urandom_fd = open("/dev/urandom", O_RDONLY); 75 if (urandom_fd < 0) 76 return false; 77 78 return true; 79 } 80 81 static int _urandom(void *ctx, unsigned char *out, size_t len) 82 { 83 if (read(urandom_fd, out, len) < 0) 84 return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; 85 86 return 0; 87 } 88 89 #define AES_GCM_CIPHERS(v) \ 90 MBEDTLS_TLS_##v##_WITH_AES_128_GCM_SHA256, \ 91 MBEDTLS_TLS_##v##_WITH_AES_256_GCM_SHA384 92 93 #define AES_CBC_CIPHERS(v) \ 94 MBEDTLS_TLS_##v##_WITH_AES_128_CBC_SHA, \ 95 MBEDTLS_TLS_##v##_WITH_AES_256_CBC_SHA 96 97 #define AES_CIPHERS(v) \ 98 AES_GCM_CIPHERS(v), \ 99 AES_CBC_CIPHERS(v) 100 101 static const int default_ciphersuites_server[] = 102 { 103 MBEDTLS_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 104 AES_GCM_CIPHERS(ECDHE_ECDSA), 105 MBEDTLS_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 106 AES_GCM_CIPHERS(ECDHE_RSA), 107 AES_CBC_CIPHERS(ECDHE_RSA), 108 AES_CIPHERS(RSA), 109 0 110 }; 111 112 static const int default_ciphersuites_client[] = 113 { 114 MBEDTLS_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256, 115 AES_GCM_CIPHERS(ECDHE_ECDSA), 116 MBEDTLS_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 117 AES_GCM_CIPHERS(ECDHE_RSA), 118 MBEDTLS_TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256, 119 AES_GCM_CIPHERS(DHE_RSA), 120 AES_CBC_CIPHERS(ECDHE_ECDSA), 121 AES_CBC_CIPHERS(ECDHE_RSA), 122 AES_CBC_CIPHERS(DHE_RSA), 123 MBEDTLS_TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA, 124 AES_CIPHERS(RSA), 125 MBEDTLS_TLS_RSA_WITH_3DES_EDE_CBC_SHA, 126 0 127 }; 128 129 130 __hidden struct ustream_ssl_ctx * 131 __ustream_ssl_context_new(bool server) 132 { 133 struct ustream_ssl_ctx *ctx; 134 mbedtls_ssl_config *conf; 135 int ep; 136 137 if (!urandom_init()) 138 return NULL; 139 140 ctx = calloc(1, sizeof(*ctx)); 141 if (!ctx) 142 return NULL; 143 144 ctx->server = server; 145 mbedtls_pk_init(&ctx->key); 146 mbedtls_x509_crt_init(&ctx->cert); 147 mbedtls_x509_crt_init(&ctx->ca_cert); 148 149 #if defined(MBEDTLS_SSL_CACHE_C) 150 mbedtls_ssl_cache_init(&ctx->cache); 151 mbedtls_ssl_cache_set_timeout(&ctx->cache, 30 * 60); 152 mbedtls_ssl_cache_set_max_entries(&ctx->cache, 5); 153 #endif 154 155 conf = &ctx->conf; 156 mbedtls_ssl_config_init(conf); 157 158 ep = server ? MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT; 159 160 mbedtls_ssl_config_defaults(conf, ep, MBEDTLS_SSL_TRANSPORT_STREAM, 161 MBEDTLS_SSL_PRESET_DEFAULT); 162 mbedtls_ssl_conf_authmode(conf, MBEDTLS_SSL_VERIFY_NONE); 163 mbedtls_ssl_conf_rng(conf, _urandom, NULL); 164 165 if (server) { 166 mbedtls_ssl_conf_ciphersuites(conf, default_ciphersuites_server); 167 mbedtls_ssl_conf_min_version(conf, MBEDTLS_SSL_MAJOR_VERSION_3, 168 MBEDTLS_SSL_MINOR_VERSION_3); 169 } else 170 mbedtls_ssl_conf_ciphersuites(conf, default_ciphersuites_client); 171 172 #if defined(MBEDTLS_SSL_CACHE_C) 173 mbedtls_ssl_conf_session_cache(conf, &ctx->cache, 174 mbedtls_ssl_cache_get, 175 mbedtls_ssl_cache_set); 176 #endif 177 return ctx; 178 } 179 180 static void ustream_ssl_update_own_cert(struct ustream_ssl_ctx *ctx) 181 { 182 if (!ctx->cert.version) 183 return; 184 185 if (!ctx->key.pk_info) 186 return; 187 188 mbedtls_ssl_conf_own_cert(&ctx->conf, &ctx->cert, &ctx->key); 189 } 190 191 __hidden int __ustream_ssl_add_ca_crt_file(struct ustream_ssl_ctx *ctx, const char *file) 192 { 193 int ret; 194 195 ret = mbedtls_x509_crt_parse_file(&ctx->ca_cert, file); 196 if (ret) 197 return -1; 198 199 mbedtls_ssl_conf_ca_chain(&ctx->conf, &ctx->ca_cert, NULL); 200 mbedtls_ssl_conf_authmode(&ctx->conf, MBEDTLS_SSL_VERIFY_OPTIONAL); 201 return 0; 202 } 203 204 __hidden int __ustream_ssl_set_crt_file(struct ustream_ssl_ctx *ctx, const char *file) 205 { 206 int ret; 207 208 ret = mbedtls_x509_crt_parse_file(&ctx->cert, file); 209 if (ret) 210 return -1; 211 212 ustream_ssl_update_own_cert(ctx); 213 return 0; 214 } 215 216 __hidden int __ustream_ssl_set_key_file(struct ustream_ssl_ctx *ctx, const char *file) 217 { 218 int ret; 219 220 ret = mbedtls_pk_parse_keyfile(&ctx->key, file, NULL); 221 if (ret) 222 return -1; 223 224 ustream_ssl_update_own_cert(ctx); 225 return 0; 226 } 227 228 __hidden int __ustream_ssl_set_ciphers(struct ustream_ssl_ctx *ctx, const char *ciphers) 229 { 230 int *ciphersuites = NULL, *tmp, id; 231 char *cipherstr, *p, *last, c; 232 size_t len = 0; 233 234 if (ciphers == NULL) 235 return -1; 236 237 cipherstr = strdup(ciphers); 238 239 if (cipherstr == NULL) 240 return -1; 241 242 for (p = cipherstr, last = p;; p++) { 243 if (*p == ':' || *p == 0) { 244 c = *p; 245 *p = 0; 246 247 id = mbedtls_ssl_get_ciphersuite_id(last); 248 249 if (id != 0) { 250 tmp = realloc(ciphersuites, (len + 2) * sizeof(int)); 251 252 if (tmp == NULL) { 253 free(ciphersuites); 254 free(cipherstr); 255 256 return -1; 257 } 258 259 ciphersuites = tmp; 260 ciphersuites[len++] = id; 261 ciphersuites[len] = 0; 262 } 263 264 if (c == 0) 265 break; 266 267 last = p + 1; 268 } 269 270 /* 271 * mbedTLS expects cipher names with dashes while many sources elsewhere 272 * like the Firefox wiki or Wireshark specify ciphers with underscores, 273 * so simply convert all underscores to dashes to accept both notations. 274 */ 275 else if (*p == '_') { 276 *p = '-'; 277 } 278 } 279 280 free(cipherstr); 281 282 if (len == 0) 283 return -1; 284 285 mbedtls_ssl_conf_ciphersuites(&ctx->conf, ciphersuites); 286 free(ctx->ciphersuites); 287 288 ctx->ciphersuites = ciphersuites; 289 290 return 0; 291 } 292 293 __hidden void __ustream_ssl_context_free(struct ustream_ssl_ctx *ctx) 294 { 295 #if defined(MBEDTLS_SSL_CACHE_C) 296 mbedtls_ssl_cache_free(&ctx->cache); 297 #endif 298 mbedtls_pk_free(&ctx->key); 299 mbedtls_x509_crt_free(&ctx->ca_cert); 300 mbedtls_x509_crt_free(&ctx->cert); 301 mbedtls_ssl_config_free(&ctx->conf); 302 free(ctx->ciphersuites); 303 free(ctx); 304 } 305 306 static void ustream_ssl_error(struct ustream_ssl *us, int ret) 307 { 308 us->error = ret; 309 uloop_timeout_set(&us->error_timer, 0); 310 } 311 312 static bool ssl_do_wait(int ret) 313 { 314 switch(ret) { 315 case MBEDTLS_ERR_SSL_WANT_READ: 316 case MBEDTLS_ERR_SSL_WANT_WRITE: 317 return true; 318 default: 319 return false; 320 } 321 } 322 323 static void ustream_ssl_verify_cert(struct ustream_ssl *us) 324 { 325 void *ssl = us->ssl; 326 const char *msg = NULL; 327 bool cn_mismatch; 328 int r; 329 330 r = mbedtls_ssl_get_verify_result(ssl); 331 cn_mismatch = r & MBEDTLS_X509_BADCERT_CN_MISMATCH; 332 r &= ~MBEDTLS_X509_BADCERT_CN_MISMATCH; 333 334 if (r & MBEDTLS_X509_BADCERT_EXPIRED) 335 msg = "certificate has expired"; 336 else if (r & MBEDTLS_X509_BADCERT_REVOKED) 337 msg = "certificate has been revoked"; 338 else if (r & MBEDTLS_X509_BADCERT_NOT_TRUSTED) 339 msg = "certificate is self-signed or not signed by a trusted CA"; 340 else 341 msg = "unknown error"; 342 343 if (r) { 344 if (us->notify_verify_error) 345 us->notify_verify_error(us, r, msg); 346 return; 347 } 348 349 if (!cn_mismatch) 350 us->valid_cn = true; 351 } 352 353 __hidden enum ssl_conn_status __ustream_ssl_connect(struct ustream_ssl *us) 354 { 355 void *ssl = us->ssl; 356 int r; 357 358 r = mbedtls_ssl_handshake(ssl); 359 if (r == 0) { 360 ustream_ssl_verify_cert(us); 361 return U_SSL_OK; 362 } 363 364 if (ssl_do_wait(r)) 365 return U_SSL_PENDING; 366 367 ustream_ssl_error(us, r); 368 return U_SSL_ERROR; 369 } 370 371 __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int len) 372 { 373 void *ssl = us->ssl; 374 int done = 0, ret = 0; 375 376 while (done != len) { 377 ret = mbedtls_ssl_write(ssl, (const unsigned char *) buf + done, len - done); 378 379 if (ret < 0) { 380 if (ssl_do_wait(ret)) 381 return done; 382 383 ustream_ssl_error(us, ret); 384 return -1; 385 } 386 387 done += ret; 388 } 389 390 return done; 391 } 392 393 __hidden int __ustream_ssl_read(struct ustream_ssl *us, char *buf, int len) 394 { 395 int ret = mbedtls_ssl_read(us->ssl, (unsigned char *) buf, len); 396 397 if (ret < 0) { 398 if (ssl_do_wait(ret)) 399 return U_SSL_PENDING; 400 401 if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY) 402 return 0; 403 404 ustream_ssl_error(us, ret); 405 return U_SSL_ERROR; 406 } 407 408 return ret; 409 } 410 411 __hidden void *__ustream_ssl_session_new(struct ustream_ssl_ctx *ctx) 412 { 413 mbedtls_ssl_context *ssl; 414 415 ssl = calloc(1, sizeof(*ssl)); 416 if (!ssl) 417 return NULL; 418 419 mbedtls_ssl_init(ssl); 420 421 if (mbedtls_ssl_setup(ssl, &ctx->conf)) { 422 free(ssl); 423 return NULL; 424 } 425 426 return ssl; 427 } 428 429 __hidden void __ustream_ssl_session_free(void *ssl) 430 { 431 mbedtls_ssl_free(ssl); 432 free(ssl); 433 } 434
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