ustream-polarssl.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 <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 POLARSSL_ERR_NET_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 POLARSSL_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         ssl_set_bio(ssl, s_ustream_read, conn, s_ustream_write, conn);
  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 POLARSSL_ERR_ENTROPY_SOURCE_FAILED;
  85
  86         return 0;
  87 }
  88
  89 __hidden struct ustream_ssl_ctx *
  90 __ustream_ssl_context_new(bool server)
  91 {
  92         struct ustream_ssl_ctx *ctx;
  93
  94         if (!urandom_init())
  95                 return NULL;
  96
  97         ctx = calloc(1, sizeof(*ctx));
  98         if (!ctx)
  99                 return NULL;
 100
 101         ctx->server = server;
 102         pk_init(&ctx->key);
 103         x509_crt_init(&ctx->ca_cert);
 104         x509_crt_init(&ctx->cert);
 105
 106         return ctx;
 107 }
 108
 109 __hidden int __ustream_ssl_add_ca_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 110 {
 111         int ret;
 112
 113         ret = x509_crt_parse_file(&ctx->ca_cert, file);
 114         if (ret)
 115                 return -1;
 116
 117         return 0;
 118 }
 119
 120 __hidden int __ustream_ssl_set_crt_file(struct ustream_ssl_ctx *ctx, const char *file)
 121 {
 122         int ret;
 123
 124         ret = x509_crt_parse_file(&ctx->cert, file);
 125         if (ret)
 126                 return -1;
 127
 128         return 0;
 129 }
 130
 131 __hidden int __ustream_ssl_set_key_file(struct ustream_ssl_ctx *ctx, const char *file)
 132 {
 133         int ret;
 134
 135         ret = pk_parse_keyfile(&ctx->key, file, NULL);
 136         if (ret)
 137                 return -1;
 138
 139         return 0;
 140 }
 141
 142 __hidden void __ustream_ssl_context_free(struct ustream_ssl_ctx *ctx)
 143 {
 144         pk_free(&ctx->key);
 145         x509_crt_free(&ctx->ca_cert);
 146         x509_crt_free(&ctx->cert);
 147         free(ctx);
 148 }
 149
 150 static void ustream_ssl_error(struct ustream_ssl *us, int ret)
 151 {
 152         us->error = ret;
 153         uloop_timeout_set(&us->error_timer, 0);
 154 }
 155
 156 static bool ssl_do_wait(int ret)
 157 {
 158         switch(ret) {
 159         case POLARSSL_ERR_NET_WANT_READ:
 160         case POLARSSL_ERR_NET_WANT_WRITE:
 161                 return true;
 162         default:
 163                 return false;
 164         }
 165 }
 166
 167 static void ustream_ssl_verify_cert(struct ustream_ssl *us)
 168 {
 169         void *ssl = us->ssl;
 170         const char *msg = NULL;
 171         bool cn_mismatch;
 172         int r;
 173
 174         r = ssl_get_verify_result(ssl);
 175         cn_mismatch = r & BADCERT_CN_MISMATCH;
 176         r &= ~BADCERT_CN_MISMATCH;
 177
 178         if (r & BADCERT_EXPIRED)
 179                 msg = "certificate has expired";
 180         else if (r & BADCERT_REVOKED)
 181                 msg = "certificate has been revoked";
 182         else if (r & BADCERT_NOT_TRUSTED)
 183                 msg = "certificate is self-signed or not signed by a trusted CA";
 184         else
 185                 msg = "unknown error";
 186
 187         if (r) {
 188                 if (us->notify_verify_error)
 189                         us->notify_verify_error(us, r, msg);
 190                 return;
 191         }
 192
 193         if (!cn_mismatch)
 194                 us->valid_cn = true;
 195 }
 196
 197 __hidden enum ssl_conn_status __ustream_ssl_connect(struct ustream_ssl *us)
 198 {
 199         void *ssl = us->ssl;
 200         int r;
 201
 202         r = ssl_handshake(ssl);
 203         if (r == 0) {
 204                 ustream_ssl_verify_cert(us);
 205                 return U_SSL_OK;
 206         }
 207
 208         if (ssl_do_wait(r))
 209                 return U_SSL_PENDING;
 210
 211         ustream_ssl_error(us, r);
 212         return U_SSL_ERROR;
 213 }
 214
 215 __hidden int __ustream_ssl_write(struct ustream_ssl *us, const char *buf, int len)
 216 {
 217         void *ssl = us->ssl;
 218         int done = 0, ret = 0;
 219
 220         while (done != len) {
 221                 ret = ssl_write(ssl, (const unsigned char *) buf + done, len - done);
 222
 223                 if (ret < 0) {
 224                         if (ssl_do_wait(ret))
 225                                 return done;
 226
 227                         ustream_ssl_error(us, ret);
 228                         return -1;
 229                 }
 230
 231                 done += ret;
 232         }
 233
 234         return done;
 235 }
 236
 237 __hidden int __ustream_ssl_read(struct ustream_ssl *us, char *buf, int len)
 238 {
 239         int ret = ssl_read(us->ssl, (unsigned char *) buf, len);
 240
 241         if (ret < 0) {
 242                 if (ssl_do_wait(ret))
 243                         return U_SSL_PENDING;
 244
 245                 ustream_ssl_error(us, ret);
 246                 return U_SSL_ERROR;
 247         }
 248
 249         return ret;
 250 }
 251
 252 #define TLS_DEFAULT_CIPHERS                     \
 253     TLS_CIPHER(AES_256_CBC_SHA256)              \
 254     TLS_CIPHER(AES_256_GCM_SHA384)              \
 255     TLS_CIPHER(AES_256_CBC_SHA)                 \
 256     TLS_CIPHER(CAMELLIA_256_CBC_SHA256)         \
 257     TLS_CIPHER(CAMELLIA_256_CBC_SHA)            \
 258     TLS_CIPHER(AES_128_CBC_SHA256)              \
 259     TLS_CIPHER(AES_128_GCM_SHA256)              \
 260     TLS_CIPHER(AES_128_CBC_SHA)                 \
 261     TLS_CIPHER(CAMELLIA_128_CBC_SHA256)         \
 262     TLS_CIPHER(CAMELLIA_128_CBC_SHA)            \
 263     TLS_CIPHER(3DES_EDE_CBC_SHA)
 264
 265 static const int default_ciphersuites_nodhe[] =
 266 {
 267 #define TLS_CIPHER(v)                           \
 268         TLS_RSA_WITH_##v,
 269         TLS_DEFAULT_CIPHERS
 270 #undef TLS_CIPHER
 271         0
 272 };
 273
 274 static const int default_ciphersuites[] =
 275 {
 276 #define TLS_CIPHER(v)                           \
 277         TLS_DHE_RSA_WITH_##v,                   \
 278         TLS_RSA_WITH_##v,
 279         TLS_DEFAULT_CIPHERS
 280 #undef TLS_CIPHER
 281         0
 282 };
 283
 284 __hidden void *__ustream_ssl_session_new(struct ustream_ssl_ctx *ctx)
 285 {
 286         ssl_context *ssl;
 287         int auth;
 288         int ep;
 289
 290         ssl = calloc(1, sizeof(ssl_context));
 291         if (!ssl)
 292                 return NULL;
 293
 294         if (ssl_init(ssl)) {
 295                 free(ssl);
 296                 return NULL;
 297         }
 298
 299         if (ctx->server) {
 300                 ep = SSL_IS_SERVER;
 301                 auth = SSL_VERIFY_NONE;
 302         } else {
 303                 ep = SSL_IS_CLIENT;
 304                 auth = SSL_VERIFY_OPTIONAL;
 305         }
 306
 307         ssl_set_endpoint(ssl, ep);
 308         ssl_set_authmode(ssl, auth);
 309         ssl_set_rng(ssl, _urandom, NULL);
 310
 311         if (ctx->server) {
 312                 ssl_set_ciphersuites(ssl, default_ciphersuites_nodhe);
 313                 if (ctx->cert.next)
 314                         ssl_set_ca_chain(ssl, ctx->cert.next, NULL, NULL);
 315                 ssl_set_own_cert(ssl, &ctx->cert, &ctx->key);
 316         } else {
 317                 ssl_set_ciphersuites(ssl, default_ciphersuites);
 318                 ssl_set_ca_chain(ssl, &ctx->ca_cert, NULL, NULL);
 319         }
 320
 321         ssl_session_reset(ssl);
 322
 323         return ssl;
 324 }
 325
 326 __hidden void __ustream_ssl_session_free(void *ssl)
 327 {
 328         ssl_free(ssl);
 329         free(ssl);
 330 }
 331
 332 __hidden void __ustream_ssl_update_peer_cn(struct ustream_ssl *us)
 333 {
 334         struct ustream_ssl_ctx *ctx = us->ctx;
 335
 336         ssl_set_ca_chain(us->ssl, &ctx->ca_cert, NULL, us->peer_cn);
 337 }