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 #include <openssl/x509v3.h>
  24
  25 /* Ciphersuite preference:
  26  * - for server, no weak ciphers are used if you use an ECDSA key.
  27  * - forward-secret (pfs), authenticated (AEAD) ciphers are at the top:
  28  *      chacha20-poly1305, the fastest in software, 256-bits
  29  *      aes128-gcm, 128-bits
  30  *      aes256-gcm, 256-bits
  31  * - key exchange: prefer ECDHE, then DHE (client only)
  32  * - forward-secret ECDSA CBC ciphers (client-only)
  33  * - forward-secret RSA CBC ciphers
  34  * - non-pfs ciphers
  35  *      aes128, aes256, 3DES(client only)
  36  */
  37
  38 #ifdef WOLFSSL_SSL_H
  39 # define top_ciphers                                                    \
  40                                 "TLS13-CHACHA20-POLY1305-SHA256:"       \
  41                                 "TLS13-AES128-GCM-SHA256:"              \
  42                                 "TLS13-AES256-GCM-SHA384:"              \
  43                                 ecdhe_aead_ciphers
  44 #else
  45 # define tls13_ciphersuites     "TLS_CHACHA20_POLY1305_SHA256:"         \
  46                                 "TLS_AES_128_GCM_SHA256:"               \
  47                                 "TLS_AES_256_GCM_SHA384"
  48
  49 # define top_ciphers                                                    \
  50                                 ecdhe_aead_ciphers
  51 #endif
  52
  53 #define ecdhe_aead_ciphers                                              \
  54                                 "ECDHE-ECDSA-CHACHA20-POLY1305:"        \
  55                                 "ECDHE-ECDSA-AES128-GCM-SHA256:"        \
  56                                 "ECDHE-ECDSA-AES256-GCM-SHA384:"        \
  57                                 "ECDHE-RSA-CHACHA20-POLY1305:"          \
  58                                 "ECDHE-RSA-AES128-GCM-SHA256:"          \
  59                                 "ECDHE-RSA-AES256-GCM-SHA384"
  60
  61 #define dhe_aead_ciphers                                                \
  62                                 "DHE-RSA-CHACHA20-POLY1305:"            \
  63                                 "DHE-RSA-AES128-GCM-SHA256:"            \
  64                                 "DHE-RSA-AES256-GCM-SHA384"
  65
  66 #define ecdhe_ecdsa_cbc_ciphers                                         \
  67                                 "ECDHE-ECDSA-AES128-SHA:"               \
  68                                 "ECDHE-ECDSA-AES256-SHA"
  69
  70 #define ecdhe_rsa_cbc_ciphers                                           \
  71                                 "ECDHE-RSA-AES128-SHA:"                 \
  72                                 "ECDHE-RSA-AES256-SHA"
  73
  74 #define dhe_cbc_ciphers                                                 \
  75                                 "DHE-RSA-AES128-SHA:"                   \
  76                                 "DHE-RSA-AES256-SHA:"                   \
  77                                 "DHE-DES-CBC3-SHA"
  78
  79 #define non_pfs_aes                                                     \
  80                                 "AES128-GCM-SHA256:"                    \
  81                                 "AES256-GCM-SHA384:"                    \
  82                                 "AES128-SHA:"                           \
  83                                 "AES256-SHA"
  84
  85 #define server_cipher_list                                              \
  86                                 top_ciphers ":"                         \
  87                                 ecdhe_rsa_cbc_ciphers ":"               \
  88                                 non_pfs_aes
  89
  90 #define client_cipher_list                                              \
  91                                 top_ciphers ":"                         \
  92                                 dhe_aead_ciphers ":"                    \
  93                                 ecdhe_ecdsa_cbc_ciphers ":"             \
  94                                 ecdhe_rsa_cbc_ciphers ":"               \
  95                                 dhe_cbc_ciphers ":"                     \
  96                                 non_pfs_aes ":"                         \
  97                                 "DES-CBC3-SHA"
  98
  99 __hidden struct ustream_ssl_ctx *
 100 __ustream_ssl_context_new(bool server)
 101 {
 102         const void *m;
 103         SSL_CTX *c;
 104
 105 #if OPENSSL_VERSION_NUMBER < 0x10100000L
 106         static bool _init = false;
 107
 108         if (!_init) {
 109                 SSL_load_error_strings();
 110                 SSL_library_init();
 111                 _init = true;
 112         }
 113 # ifndef TLS_server_method
 114 #  define TLS_server_method SSLv23_server_method
 115 # endif
 116 # ifndef TLS_client_method
 117 #  define TLS_client_method SSLv23_client_method
 118 # endif
 119 #endif
 120
 121         if (server) {
 122                 m = TLS_server_method();
 123         } else
 124                 m = TLS_client_method();
 125
 126         c = SSL_CTX_new((void *) m);
 127         if (!c)
 128                 return NULL;
 129
 130         SSL_CTX_set_verify(c, SSL_VERIFY_NONE, NULL);
 131         SSL_CTX_set_options(c, SSL_OP_NO_COMPRESSION | SSL_OP_SINGLE_ECDH_USE |
 132                                SSL_OP_CIPHER_SERVER_PREFERENCE);
 133 #if defined(SSL_CTX_set_ecdh_auto) && OPENSSL_VERSION_NUMBER < 0x10100000L
 134         SSL_CTX_set_ecdh_auto(c, 1);
 135 #elif OPENSSL_VERSION_NUMBER >= 0x10101000L
 136         SSL_CTX_set_ciphersuites(c, tls13_ciphersuites);
 137 #endif
 138         if (server) {
 139 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
 140                 SSL_CTX_set_min_proto_version(c, TLS1_2_VERSION);
 141 #else
 142                 SSL_CTX_set_options(c, SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1 |
 143                                        SSL_OP_NO_TLSv1_1);
 144 #endif
 145                 SSL_CTX_set_cipher_list(c, server_cipher_list);
 146         } else {
 147                 SSL_CTX_set_cipher_list(c, client_cipher_list);
 148         }
 149         SSL_CTX_set_quiet_shutdown(c, 1);
 150
 151         return (void *) c;
 152 }
 153
 154 __hidden int __ustream_ssl_add_ca_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 155 {
 156         int ret;
 157
 158         ret = SSL_CTX_load_verify_locations((void *) ctx, file, NULL);
 159         if (ret < 1)
 160                 return -1;
 161
 162         return 0;
 163 }
 164
 165 __hidden int __ustream_ssl_set_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 166 {
 167         int ret;
 168
 169         ret = SSL_CTX_use_certificate_chain_file((void *) ctx, file);
 170         if (ret < 1)
 171                 ret = SSL_CTX_use_certificate_file((void *) ctx, file, SSL_FILETYPE_ASN1);
 172
 173         if (ret < 1)
 174                 return -1;
 175
 176         return 0;
 177 }
 178
 179 __hidden int __ustream_ssl_set_key_file(struct ustream_ssl_ctx *ctx, const char *file)
 180 {
 181         int ret;
 182
 183         ret = SSL_CTX_use_PrivateKey_file((void *) ctx, file, SSL_FILETYPE_PEM);
 184         if (ret < 1)
 185                 ret = SSL_CTX_use_PrivateKey_file((void *) ctx, file, SSL_FILETYPE_ASN1);
 186
 187         if (ret < 1)
 188                 return -1;
 189
 190         return 0;
 191 }
 192
 193 __hidden void __ustream_ssl_context_free(struct ustream_ssl_ctx *ctx)
 194 {
 195         SSL_CTX_free((void *) ctx);
 196 }
 197
 198 void __ustream_ssl_session_free(void *ssl)
 199 {
 200         SSL_shutdown(ssl);
 201         SSL_free(ssl);
 202 }
 203
 204 static void ustream_ssl_error(struct ustream_ssl *us, int ret)
 205 {
 206         us->error = ret;
 207         uloop_timeout_set(&us->error_timer, 0);
 208 }
 209
 210 #ifndef NO_X509_CHECK_HOST
 211
 212 static bool ustream_ssl_verify_cn(struct ustream_ssl *us, X509 *cert)
 213 {
 214         int ret;
 215
 216         if (!us->peer_cn)
 217                 return false;
 218
 219 # ifndef WOLFSSL_OPENSSL_H_
 220         ret = X509_check_host(cert, us->peer_cn, 0, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS, NULL);
 221 # else
 222         ret = wolfSSL_X509_check_host(cert, us->peer_cn, 0, 0, NULL);
 223 # endif
 224         return ret == 1;
 225 }
 226
 227 #endif
 228
 229 static void ustream_ssl_verify_cert(struct ustream_ssl *us)
 230 {
 231         void *ssl = us->ssl;
 232         X509 *cert;
 233         int res;
 234
 235         res = SSL_get_verify_result(ssl);
 236         if (res != X509_V_OK) {
 237                 if (us->notify_verify_error)
 238                         us->notify_verify_error(us, res, X509_verify_cert_error_string(res));
 239                 return;
 240         }
 241
 242         cert = SSL_get_peer_certificate(ssl);
 243         if (!cert)
 244                 return;
 245
 246         us->valid_cert = true;
 247 #ifndef NO_X509_CHECK_HOST
 248         us->valid_cn = ustream_ssl_verify_cn(us, cert);
 249 #endif
 250         X509_free(cert);
 251 }
 252
 253
 254 __hidden enum ssl_conn_status __ustream_ssl_connect(struct ustream_ssl *us)
 255 {
 256         void *ssl = us->ssl;
 257         int r;
 258
 259         if (us->server)
 260                 r = SSL_accept(ssl);
 261         else
 262                 r = SSL_connect(ssl);
 263
 264         if (r == 1) {
 265                 ustream_ssl_verify_cert(us);
 266                 return U_SSL_OK;
 267         }
 268
 269         r = SSL_get_error(ssl, r);
 270         if (r == SSL_ERROR_WANT_READ || r == SSL_ERROR_WANT_WRITE)
 271                 return U_SSL_PENDING;
 272
 273         ustream_ssl_error(us, r);
 274         return U_SSL_ERROR;
 275 }
 276
 277 __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int len)
 278 {
 279         void *ssl = us->ssl;
 280         int ret = SSL_write(ssl, buf, len);
 281
 282         if (ret < 0) {
 283                 int err = SSL_get_error(ssl, ret);
 284                 if (err == SSL_ERROR_WANT_WRITE)
 285                         return 0;
 286
 287                 ustream_ssl_error(us, err);
 288                 return -1;
 289         }
 290
 291         return ret;
 292 }
 293
 294 __hidden int __ustream_ssl_read(struct ustream_ssl *us, char *buf, int len)
 295 {
 296         int ret = SSL_read(us->ssl, buf, len);
 297
 298         if (ret < 0) {
 299                 ret = SSL_get_error(us->ssl, ret);
 300                 if (ret == SSL_ERROR_WANT_READ)
 301                         return U_SSL_PENDING;
 302
 303                 ustream_ssl_error(us, ret);
 304                 return U_SSL_ERROR;
 305         }
 306
 307         return ret;
 308 }
 309