ustream-mbedtls.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 <sys/types.h>
  20 #include <sys/random.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "ustream-ssl.h"
  27 #include "ustream-internal.h"
  28 #include <psa/crypto.h>
  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 ((size_t) 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 int _random(void *ctx, unsigned char *out, size_t len)
  70 {
  71 #ifdef linux
  72         if (getrandom(out, len, 0) != (ssize_t) len)
  73                 return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
  74 #else
  75         static FILE *f;
  76
  77         if (!f)
  78                 f = fopen("/dev/urandom", "r");
  79         if (fread(out, len, 1, f) != 1)
  80                 return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
  81 #endif
  82
  83         return 0;
  84 }
  85
  86 #define AES_GCM_CIPHERS(v)                              \
  87         MBEDTLS_TLS_##v##_WITH_AES_128_GCM_SHA256,      \
  88         MBEDTLS_TLS_##v##_WITH_AES_256_GCM_SHA384
  89
  90 #define AES_CBC_CIPHERS(v)                              \
  91         MBEDTLS_TLS_##v##_WITH_AES_128_CBC_SHA,         \
  92         MBEDTLS_TLS_##v##_WITH_AES_256_CBC_SHA
  93
  94 #define AES_CIPHERS(v)                                  \
  95         AES_GCM_CIPHERS(v),                             \
  96         AES_CBC_CIPHERS(v)
  97
  98 static const int default_ciphersuites_server[] =
  99 {
 100         MBEDTLS_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
 101         AES_GCM_CIPHERS(ECDHE_ECDSA),
 102         MBEDTLS_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
 103         AES_GCM_CIPHERS(ECDHE_RSA),
 104         AES_CBC_CIPHERS(ECDHE_RSA),
 105         AES_CIPHERS(RSA),
 106         0
 107 };
 108
 109 static const int default_ciphersuites_client[] =
 110 {
 111         MBEDTLS_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
 112         AES_GCM_CIPHERS(ECDHE_ECDSA),
 113         MBEDTLS_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
 114         AES_GCM_CIPHERS(ECDHE_RSA),
 115         MBEDTLS_TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
 116         AES_GCM_CIPHERS(DHE_RSA),
 117         AES_CBC_CIPHERS(ECDHE_ECDSA),
 118         AES_CBC_CIPHERS(ECDHE_RSA),
 119         AES_CBC_CIPHERS(DHE_RSA),
 120 /* Removed in Mbed TLS 3.0.0 */
 121 #ifdef MBEDTLS_TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
 122         MBEDTLS_TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
 123 #endif
 124         AES_CIPHERS(RSA),
 125 /* Removed in Mbed TLS 3.0.0 */
 126 #ifdef MBEDTLS_TLS_RSA_WITH_3DES_EDE_CBC_SHA
 127         MBEDTLS_TLS_RSA_WITH_3DES_EDE_CBC_SHA,
 128 #endif
 129         0
 130 };
 131
 132
 133 __hidden struct ustream_ssl_ctx *
 134 __ustream_ssl_context_new(bool server)
 135 {
 136         struct ustream_ssl_ctx *ctx;
 137         mbedtls_ssl_config *conf;
 138         int ep;
 139
 140 #ifdef MBEDTLS_PSA_CRYPTO_C
 141         static bool psa_init;
 142
 143         if (!psa_init && !psa_crypto_init())
 144                 psa_init = true;
 145 #endif
 146
 147         ctx = calloc(1, sizeof(*ctx));
 148         if (!ctx)
 149                 return NULL;
 150
 151         ctx->server = server;
 152         mbedtls_pk_init(&ctx->key);
 153         mbedtls_x509_crt_init(&ctx->cert);
 154         mbedtls_x509_crt_init(&ctx->ca_cert);
 155
 156 #if defined(MBEDTLS_SSL_CACHE_C)
 157         mbedtls_ssl_cache_init(&ctx->cache);
 158         mbedtls_ssl_cache_set_timeout(&ctx->cache, 30 * 60);
 159         mbedtls_ssl_cache_set_max_entries(&ctx->cache, 5);
 160 #endif
 161
 162         conf = &ctx->conf;
 163         mbedtls_ssl_config_init(conf);
 164
 165         ep = server ? MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT;
 166
 167         mbedtls_ssl_config_defaults(conf, ep, MBEDTLS_SSL_TRANSPORT_STREAM,
 168                                     MBEDTLS_SSL_PRESET_DEFAULT);
 169         mbedtls_ssl_conf_rng(conf, _random, NULL);
 170
 171         if (server) {
 172                 mbedtls_ssl_conf_authmode(conf, MBEDTLS_SSL_VERIFY_NONE);
 173                 mbedtls_ssl_conf_ciphersuites(conf, default_ciphersuites_server);
 174                 mbedtls_ssl_conf_min_version(conf, MBEDTLS_SSL_MAJOR_VERSION_3,
 175                                              MBEDTLS_SSL_MINOR_VERSION_3);
 176         } else {
 177                 mbedtls_ssl_conf_authmode(conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
 178                 mbedtls_ssl_conf_ciphersuites(conf, default_ciphersuites_client);
 179         }
 180
 181 #if defined(MBEDTLS_SSL_CACHE_C)
 182         mbedtls_ssl_conf_session_cache(conf, &ctx->cache,
 183                                        mbedtls_ssl_cache_get,
 184                                        mbedtls_ssl_cache_set);
 185 #endif
 186         return ctx;
 187 }
 188
 189 static void ustream_ssl_update_own_cert(struct ustream_ssl_ctx *ctx)
 190 {
 191         if (!ctx->cert.version)
 192                 return;
 193
 194         if (mbedtls_pk_get_type(&ctx->key) == MBEDTLS_PK_NONE)
 195                 return;
 196
 197         mbedtls_ssl_conf_own_cert(&ctx->conf, &ctx->cert, &ctx->key);
 198 }
 199
 200 __hidden int __ustream_ssl_add_ca_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 201 {
 202         int ret;
 203
 204         ret = mbedtls_x509_crt_parse_file(&ctx->ca_cert, file);
 205         if (ret)
 206                 return -1;
 207
 208         mbedtls_ssl_conf_ca_chain(&ctx->conf, &ctx->ca_cert, NULL);
 209         mbedtls_ssl_conf_authmode(&ctx->conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
 210         return 0;
 211 }
 212
 213 __hidden int __ustream_ssl_set_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 214 {
 215         int ret;
 216
 217         ret = mbedtls_x509_crt_parse_file(&ctx->cert, file);
 218         if (ret)
 219                 return -1;
 220
 221         ustream_ssl_update_own_cert(ctx);
 222         return 0;
 223 }
 224
 225 __hidden int __ustream_ssl_set_key_file(struct ustream_ssl_ctx *ctx, const char *file)
 226 {
 227         int ret;
 228
 229 #if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
 230         ret = mbedtls_pk_parse_keyfile(&ctx->key, file, NULL, _random, NULL);
 231 #else
 232         ret = mbedtls_pk_parse_keyfile(&ctx->key, file, NULL);
 233 #endif
 234         if (ret)
 235                 return -1;
 236
 237         ustream_ssl_update_own_cert(ctx);
 238         return 0;
 239 }
 240
 241 __hidden int __ustream_ssl_set_ciphers(struct ustream_ssl_ctx *ctx, const char *ciphers)
 242 {
 243         int *ciphersuites = NULL, *tmp, id;
 244         char *cipherstr, *p, *last, c;
 245         size_t len = 0;
 246
 247         if (ciphers == NULL)
 248                 return -1;
 249
 250         cipherstr = strdup(ciphers);
 251
 252         if (cipherstr == NULL)
 253                 return -1;
 254
 255         for (p = cipherstr, last = p;; p++) {
 256                 if (*p == ':' || *p == 0) {
 257                         c = *p;
 258                         *p = 0;
 259
 260                         id = mbedtls_ssl_get_ciphersuite_id(last);
 261
 262                         if (id != 0) {
 263                                 tmp = realloc(ciphersuites, (len + 2) * sizeof(int));
 264
 265                                 if (tmp == NULL) {
 266                                         free(ciphersuites);
 267                                         free(cipherstr);
 268
 269                                         return -1;
 270                                 }
 271
 272                                 ciphersuites = tmp;
 273                                 ciphersuites[len++] = id;
 274                                 ciphersuites[len] = 0;
 275                         }
 276
 277                         if (c == 0)
 278                                 break;
 279
 280                         last = p + 1;
 281                 }
 282
 283                 /*
 284                  * mbedTLS expects cipher names with dashes while many sources elsewhere
 285                  * like the Firefox wiki or Wireshark specify ciphers with underscores,
 286                  * so simply convert all underscores to dashes to accept both notations.
 287                  */
 288                 else if (*p == '_') {
 289                         *p = '-';
 290                 }
 291         }
 292
 293         free(cipherstr);
 294
 295         if (len == 0)
 296                 return -1;
 297
 298         mbedtls_ssl_conf_ciphersuites(&ctx->conf, ciphersuites);
 299         free(ctx->ciphersuites);
 300
 301         ctx->ciphersuites = ciphersuites;
 302
 303         return 0;
 304 }
 305
 306 __hidden int __ustream_ssl_set_require_validation(struct ustream_ssl_ctx *ctx, bool require)
 307 {
 308         int mode = MBEDTLS_SSL_VERIFY_OPTIONAL;
 309
 310         if (!require)
 311                 mode = MBEDTLS_SSL_VERIFY_NONE;
 312
 313         mbedtls_ssl_conf_authmode(&ctx->conf, mode);
 314
 315         return 0;
 316 }
 317
 318 __hidden void __ustream_ssl_context_free(struct ustream_ssl_ctx *ctx)
 319 {
 320 #if defined(MBEDTLS_SSL_CACHE_C)
 321         mbedtls_ssl_cache_free(&ctx->cache);
 322 #endif
 323         mbedtls_pk_free(&ctx->key);
 324         mbedtls_x509_crt_free(&ctx->ca_cert);
 325         mbedtls_x509_crt_free(&ctx->cert);
 326         mbedtls_ssl_config_free(&ctx->conf);
 327         free(ctx->ciphersuites);
 328         free(ctx);
 329 }
 330
 331 static void ustream_ssl_error(struct ustream_ssl *us, int ret)
 332 {
 333         us->error = ret;
 334         uloop_timeout_set(&us->error_timer, 0);
 335 }
 336
 337 static bool ssl_do_wait(int ret)
 338 {
 339         switch(ret) {
 340         case MBEDTLS_ERR_SSL_WANT_READ:
 341         case MBEDTLS_ERR_SSL_WANT_WRITE:
 342                 return true;
 343         default:
 344                 return false;
 345         }
 346 }
 347
 348 static void ustream_ssl_verify_cert(struct ustream_ssl *us)
 349 {
 350         void *ssl = us->ssl;
 351         const char *msg = NULL;
 352         bool cn_mismatch;
 353         int r;
 354
 355         r = mbedtls_ssl_get_verify_result(ssl);
 356         cn_mismatch = r & MBEDTLS_X509_BADCERT_CN_MISMATCH;
 357         r &= ~MBEDTLS_X509_BADCERT_CN_MISMATCH;
 358
 359         if (r & MBEDTLS_X509_BADCERT_EXPIRED)
 360                 msg = "certificate has expired";
 361         else if (r & MBEDTLS_X509_BADCERT_REVOKED)
 362                 msg = "certificate has been revoked";
 363         else if (r & MBEDTLS_X509_BADCERT_NOT_TRUSTED)
 364                 msg = "certificate is self-signed or not signed by a trusted CA";
 365         else
 366                 msg = "unknown error";
 367
 368         if (r) {
 369                 if (us->notify_verify_error)
 370                         us->notify_verify_error(us, r, msg);
 371                 return;
 372         }
 373
 374         if (!cn_mismatch)
 375                 us->valid_cn = true;
 376 }
 377
 378 __hidden enum ssl_conn_status __ustream_ssl_connect(struct ustream_ssl *us)
 379 {
 380         void *ssl = us->ssl;
 381         int r;
 382
 383         r = mbedtls_ssl_handshake(ssl);
 384         if (r == 0) {
 385                 ustream_ssl_verify_cert(us);
 386                 return U_SSL_OK;
 387         }
 388
 389         if (ssl_do_wait(r))
 390                 return U_SSL_PENDING;
 391
 392         ustream_ssl_error(us, r);
 393         return U_SSL_ERROR;
 394 }
 395
 396 __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int len)
 397 {
 398         void *ssl = us->ssl;
 399         int done = 0, ret = 0;
 400
 401         while (done != len) {
 402                 ret = mbedtls_ssl_write(ssl, (const unsigned char *) buf + done, len - done);
 403
 404                 if (ret < 0) {
 405                         if (ssl_do_wait(ret))
 406                                 return done;
 407
 408                         ustream_ssl_error(us, ret);
 409                         return -1;
 410                 }
 411
 412                 done += ret;
 413         }
 414
 415         return done;
 416 }
 417
 418 __hidden int __ustream_ssl_read(struct ustream_ssl *us, char *buf, int len)
 419 {
 420         int ret = mbedtls_ssl_read(us->ssl, (unsigned char *) buf, len);
 421
 422         if (ret < 0) {
 423                 if (ssl_do_wait(ret))
 424                         return U_SSL_PENDING;
 425
 426                 if (ret == MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY)
 427                         return 0;
 428
 429                 ustream_ssl_error(us, ret);
 430                 return U_SSL_ERROR;
 431         }
 432
 433         return ret;
 434 }
 435
 436 __hidden void *__ustream_ssl_session_new(struct ustream_ssl_ctx *ctx)
 437 {
 438         mbedtls_ssl_context *ssl;
 439
 440         ssl = calloc(1, sizeof(*ssl));
 441         if (!ssl)
 442                 return NULL;
 443
 444         mbedtls_ssl_init(ssl);
 445
 446         if (mbedtls_ssl_setup(ssl, &ctx->conf)) {
 447                 free(ssl);
 448                 return NULL;
 449         }
 450
 451         return ssl;
 452 }
 453
 454 __hidden void __ustream_ssl_session_free(void *ssl)
 455 {
 456         mbedtls_ssl_free(ssl);
 457         free(ssl);
 458 }