ssl/heartbeat_test.c

   1 /* test/heartbeat_test.c */
   2 /*
   3  * Unit test for TLS heartbeats.
   4  *
   5  * Acts as a regression test against the Heartbleed bug (CVE-2014-0160).
   6  *
   7  * Author:  Mike Bland (mbland@acm.org, http://mike-bland.com/)
   8  * Date:    2014-04-12
   9  * License: Creative Commons Attribution 4.0 International (CC By 4.0)
  10  *          http://creativecommons.org/licenses/by/4.0/deed.en_US
  11  *
  12  * OUTPUT
  13  * ------
  14  * The program returns zero on success. It will print a message with a count
  15  * of the number of failed tests and return nonzero if any tests fail.
  16  *
  17  * It will print the contents of the request and response buffers for each
  18  * failing test. In a "fixed" version, all the tests should pass and there
  19  * should be no output.
  20  *
  21  * In a "bleeding" version, you'll see:
  22  *
  23  *   test_dtls1_heartbleed failed:
  24  *     expected payload len: 0
  25  *     received: 1024
  26  *   sent 26 characters
  27  *     "HEARTBLEED                "
  28  *   received 1024 characters
  29  *     "HEARTBLEED                \xde\xad\xbe\xef..."
  30  *   ** test_dtls1_heartbleed failed **
  31  *
  32  * The contents of the returned buffer in the failing test will depend on the
  33  * contents of memory on your machine.
  34  *
  35  * MORE INFORMATION
  36  * ----------------
  37  * http://mike-bland.com/2014/04/12/heartbleed.html
  38  * http://mike-bland.com/tags/heartbleed.html
  39  */
  40
  41 #include "../ssl/ssl_locl.h"
  42 #include <ctype.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46
  47 /* As per https://tools.ietf.org/html/rfc6520#section-4 */
  48 static const int MIN_PADDING_SIZE = 16;
  49
  50 /* Maximum number of payload characters to print as test output */
  51 static const int MAX_PRINTABLE_CHARACTERS = 1024;
  52
  53 typedef struct heartbeat_test_fixture
  54         {
  55         SSL_CTX *ctx;
  56         SSL *s;
  57         const char* test_case_name;
  58         int (*process_heartbeat)(SSL* s);
  59         unsigned char* payload;
  60         int sent_payload_len;
  61         int expected_return_value;
  62         int return_payload_offset;
  63         int expected_payload_len;
  64         const char* expected_return_payload;
  65         } HEARTBEAT_TEST_FIXTURE;
  66
  67 static HEARTBEAT_TEST_FIXTURE set_up(const char* const test_case_name,
  68         const SSL_METHOD* meth)
  69         {
  70         HEARTBEAT_TEST_FIXTURE fixture;
  71         memset(&fixture, 0, sizeof(fixture));
  72         fixture.test_case_name = test_case_name;
  73
  74         fixture.ctx = SSL_CTX_new(meth);
  75         if (!fixture.ctx)
  76                 {
  77                 fprintf(stderr, "Failed to allocate SSL_CTX for test: %s\n",
  78                                                 test_case_name);
  79                 goto fail;
  80                 }
  81
  82         fixture.s = SSL_new(fixture.ctx);
  83         if (!fixture.s)
  84                 {
  85                 fprintf(stderr, "Failed to allocate SSL for test: %s\n", test_case_name);
  86                 goto fail;
  87                 }
  88
  89         ssl_init_wbio_buffer(fixture.s, 1);
  90         ssl3_setup_buffers(fixture.s);
  91
  92         fail:
  93         if (!fixture.s)
  94                 {
  95                 ERR_print_errors_fp(stderr);
  96                 exit(EXIT_FAILURE);
  97                 }
  98         return fixture;
  99         }
 100
 101 static HEARTBEAT_TEST_FIXTURE set_up_dtls(const char* const test_case_name)
 102         {
 103         HEARTBEAT_TEST_FIXTURE fixture = set_up(test_case_name,
 104                 DTLSv1_server_method());
 105         fixture.process_heartbeat = dtls1_process_heartbeat;
 106
 107         /* As per dtls1_get_record(), skipping the following from the beginning of
 108          * the returned heartbeat message:
 109          * type-1 byte; version-2 bytes; sequence number-8 bytes; length-2 bytes
 110          *
 111          * And then skipping the 1-byte type encoded by process_heartbeat for
 112          * a total of 14 bytes, at which point we can grab the length and the
 113          * payload we seek.
 114          */
 115         fixture.return_payload_offset = 14;
 116         return fixture;
 117         }
 118
 119 /* Needed by ssl3_write_bytes() */
 120 static int dummy_handshake(SSL* s)
 121         {
 122         return 1;
 123         }
 124
 125 static HEARTBEAT_TEST_FIXTURE set_up_tls(const char* const test_case_name)
 126         {
 127         HEARTBEAT_TEST_FIXTURE fixture = set_up(test_case_name,
 128                 TLSv1_server_method());
 129         fixture.process_heartbeat = tls1_process_heartbeat;
 130         fixture.s->handshake_func = dummy_handshake;
 131
 132         /* As per do_ssl3_write(), skipping the following from the beginning of
 133          * the returned heartbeat message:
 134          * type-1 byte; version-2 bytes; length-2 bytes
 135          *
 136          * And then skipping the 1-byte type encoded by process_heartbeat for
 137          * a total of 6 bytes, at which point we can grab the length and the payload
 138          * we seek.
 139          */
 140         fixture.return_payload_offset = 6;
 141         return fixture;
 142         }
 143
 144 static void tear_down(HEARTBEAT_TEST_FIXTURE fixture)
 145         {
 146         ERR_print_errors_fp(stderr);
 147         memset(fixture.s, 0, sizeof(*fixture.s));
 148         SSL_free(fixture.s);
 149         memset(fixture.ctx, 0, sizeof(*fixture.ctx));
 150         SSL_CTX_free(fixture.ctx);
 151         }
 152
 153 static void print_payload(const char* const prefix,
 154                 const unsigned char *payload, const int n)
 155         {
 156         const int end = n < MAX_PRINTABLE_CHARACTERS ? n : MAX_PRINTABLE_CHARACTERS;
 157         printf("%s %d character%s", prefix, n, n == 1 ? "" : "s");
 158         if (end != n) printf(" (first %d shown)", end);
 159         printf("\n  \"");
 160
 161         int i = 0;
 162         for (; i != end; ++i)
 163                 {
 164                 const unsigned char c = payload[i];
 165                 if (isprint(c)) fputc(c, stdout);
 166                 else printf("\\x%02x", c);
 167                 }
 168         printf("\"\n");
 169 }
 170
 171 static int execute_heartbeat(HEARTBEAT_TEST_FIXTURE fixture)
 172         {
 173         int result = 0;
 174         SSL* s = fixture.s;
 175         unsigned char *payload = fixture.payload;
 176         unsigned char sent_buf[MAX_PRINTABLE_CHARACTERS + 1];
 177
 178         s->s3->rrec.data = payload;
 179         s->s3->rrec.length = strlen((const char*)payload);
 180         *payload++ = TLS1_HB_REQUEST;
 181         s2n(fixture.sent_payload_len, payload);
 182
 183         /* Make a local copy of the request, since it gets overwritten at some
 184          * point */
 185         memcpy((char *)sent_buf, (const char*)payload, sizeof(sent_buf));
 186
 187         int return_value = fixture.process_heartbeat(s);
 188
 189         if (return_value != fixture.expected_return_value)
 190                 {
 191                 printf("%s failed: expected return value %d, received %d\n",
 192                                          fixture.test_case_name, fixture.expected_return_value,
 193                                          return_value);
 194                 result = 1;
 195                 }
 196
 197         /* If there is any byte alignment, it will be stored in wbuf.offset. */
 198         unsigned const char *p = &(s->s3->wbuf.buf[
 199                         fixture.return_payload_offset + s->s3->wbuf.offset]);
 200         int actual_payload_len = 0;
 201         n2s(p, actual_payload_len);
 202
 203         if (actual_payload_len != fixture.expected_payload_len)
 204                 {
 205                 printf("%s failed:\n  expected payload len: %d\n  received: %d\n",
 206                                          fixture.test_case_name, fixture.expected_payload_len,
 207                                          actual_payload_len);
 208                 print_payload("sent", sent_buf, strlen((const char*)sent_buf));
 209                 print_payload("received", p, actual_payload_len);
 210                 result = 1;
 211                 }
 212         else
 213                 {
 214                 char* actual_payload = strndup((const char*)p, actual_payload_len);
 215                 if (strcmp(actual_payload, fixture.expected_return_payload) != 0)
 216                         {
 217                         printf("%s failed:\n  expected payload: \"%s\"\n  received: \"%s\"\n",
 218                                                  fixture.test_case_name, fixture.expected_return_payload,
 219                                                  actual_payload);
 220                         result = 1;
 221                         }
 222                 free(actual_payload);
 223                 }
 224
 225         if (result != 0)
 226                 {
 227                 printf("** %s failed **\n--------\n", fixture.test_case_name);
 228                 }
 229         return result;
 230         }
 231
 232 static int honest_payload_size(unsigned char payload_buf[])
 233         {
 234         /* Omit three-byte pad at the beginning for type and payload length */
 235         return strlen((const char*)&payload_buf[3]) - MIN_PADDING_SIZE;
 236         }
 237
 238 #define SETUP_HEARTBEAT_TEST_FIXTURE(type)\
 239         HEARTBEAT_TEST_FIXTURE fixture = set_up_##type(__func__);\
 240         int result = 0
 241
 242 #define EXECUTE_HEARTBEAT_TEST()\
 243         if (execute_heartbeat(fixture) != 0) result = 1;\
 244         tear_down(fixture);\
 245         return result
 246
 247 static int test_dtls1_not_bleeding()
 248         {
 249         SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
 250         /* Three-byte pad at the beginning for type and payload length */
 251         unsigned char payload_buf[] = "   Not bleeding, sixteen spaces of padding"
 252                 "                ";
 253         const int payload_buf_len = honest_payload_size(payload_buf);
 254
 255         fixture.payload = &payload_buf[0];
 256         fixture.sent_payload_len = payload_buf_len;
 257         fixture.expected_return_value = 0;
 258         fixture.expected_payload_len = payload_buf_len;
 259         fixture.expected_return_payload = "Not bleeding, sixteen spaces of padding";
 260         EXECUTE_HEARTBEAT_TEST();
 261         }
 262
 263 static int test_dtls1_not_bleeding_empty_payload()
 264         {
 265         SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
 266         /* Three-byte pad at the beginning for type and payload length, plus a NUL
 267          * at the end */
 268         unsigned char payload_buf[4 + MIN_PADDING_SIZE];
 269         memset(payload_buf, ' ', sizeof(payload_buf));
 270         payload_buf[sizeof(payload_buf) - 1] = '\0';
 271         const int payload_buf_len = honest_payload_size(payload_buf);
 272
 273         fixture.payload = &payload_buf[0];
 274         fixture.sent_payload_len = payload_buf_len;
 275         fixture.expected_return_value = 0;
 276         fixture.expected_payload_len = payload_buf_len;
 277         fixture.expected_return_payload = "";
 278         EXECUTE_HEARTBEAT_TEST();
 279         }
 280
 281 static int test_dtls1_heartbleed()
 282         {
 283         SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
 284         /* Three-byte pad at the beginning for type and payload length */
 285         unsigned char payload_buf[] = "   HEARTBLEED                ";
 286
 287         fixture.payload = &payload_buf[0];
 288         fixture.sent_payload_len = MAX_PRINTABLE_CHARACTERS;
 289         fixture.expected_return_value = 0;
 290         fixture.expected_payload_len = 0;
 291         fixture.expected_return_payload = "";
 292         EXECUTE_HEARTBEAT_TEST();
 293         }
 294
 295 static int test_dtls1_heartbleed_empty_payload()
 296         {
 297         SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
 298         /* Excluding the NUL at the end, one byte short of type + payload length +
 299          * minimum padding */
 300         unsigned char payload_buf[MIN_PADDING_SIZE + 3];
 301         memset(payload_buf, ' ', sizeof(payload_buf));
 302         payload_buf[sizeof(payload_buf) - 1] = '\0';
 303
 304         fixture.payload = &payload_buf[0];
 305         fixture.sent_payload_len = MAX_PRINTABLE_CHARACTERS;
 306         fixture.expected_return_value = 0;
 307         fixture.expected_payload_len = 0;
 308         fixture.expected_return_payload = "";
 309         EXECUTE_HEARTBEAT_TEST();
 310         }
 311
 312 static int test_dtls1_heartbleed_excessive_plaintext_length()
 313         {
 314         SETUP_HEARTBEAT_TEST_FIXTURE(dtls);
 315         /* Excluding the NUL at the end, one byte in excess of maximum allowed
 316          * heartbeat message length */
 317         unsigned char payload_buf[SSL3_RT_MAX_PLAIN_LENGTH + 2];
 318         memset(payload_buf, ' ', sizeof(payload_buf));
 319         payload_buf[sizeof(payload_buf) - 1] = '\0';
 320
 321         fixture.payload = &payload_buf[0];
 322         fixture.sent_payload_len = honest_payload_size(payload_buf);
 323         fixture.expected_return_value = 0;
 324         fixture.expected_payload_len = 0;
 325         fixture.expected_return_payload = "";
 326         EXECUTE_HEARTBEAT_TEST();
 327         }
 328
 329 static int test_tls1_not_bleeding()
 330         {
 331         SETUP_HEARTBEAT_TEST_FIXTURE(tls);
 332         /* Three-byte pad at the beginning for type and payload length */
 333         unsigned char payload_buf[] = "   Not bleeding, sixteen spaces of padding"
 334                                         "                ";
 335         const int payload_buf_len = honest_payload_size(payload_buf);
 336
 337         fixture.payload = &payload_buf[0];
 338         fixture.sent_payload_len = payload_buf_len;
 339         fixture.expected_return_value = 0;
 340         fixture.expected_payload_len = payload_buf_len;
 341         fixture.expected_return_payload = "Not bleeding, sixteen spaces of padding";
 342         EXECUTE_HEARTBEAT_TEST();
 343         }
 344
 345 static int test_tls1_not_bleeding_empty_payload()
 346         {
 347         SETUP_HEARTBEAT_TEST_FIXTURE(tls);
 348         /* Three-byte pad at the beginning for type and payload length, plus a NUL
 349          * at the end */
 350         unsigned char payload_buf[4 + MIN_PADDING_SIZE];
 351         memset(payload_buf, ' ', sizeof(payload_buf));
 352         payload_buf[sizeof(payload_buf) - 1] = '\0';
 353         const int payload_buf_len = honest_payload_size(payload_buf);
 354
 355         fixture.payload = &payload_buf[0];
 356         fixture.sent_payload_len = payload_buf_len;
 357         fixture.expected_return_value = 0;
 358         fixture.expected_payload_len = payload_buf_len;
 359         fixture.expected_return_payload = "";
 360         EXECUTE_HEARTBEAT_TEST();
 361         }
 362
 363 static int test_tls1_heartbleed()
 364         {
 365         SETUP_HEARTBEAT_TEST_FIXTURE(tls);
 366         /* Three-byte pad at the beginning for type and payload length */
 367         unsigned char payload_buf[] = "   HEARTBLEED                ";
 368
 369         fixture.payload = &payload_buf[0];
 370         fixture.sent_payload_len = MAX_PRINTABLE_CHARACTERS;
 371         fixture.expected_return_value = 0;
 372         fixture.expected_payload_len = 0;
 373         fixture.expected_return_payload = "";
 374         EXECUTE_HEARTBEAT_TEST();
 375         }
 376
 377 static int test_tls1_heartbleed_empty_payload()
 378         {
 379         SETUP_HEARTBEAT_TEST_FIXTURE(tls);
 380         /* Excluding the NUL at the end, one byte short of type + payload length +
 381          * minimum padding */
 382         unsigned char payload_buf[MIN_PADDING_SIZE + 3];
 383         memset(payload_buf, ' ', sizeof(payload_buf));
 384         payload_buf[sizeof(payload_buf) - 1] = '\0';
 385
 386         fixture.payload = &payload_buf[0];
 387         fixture.sent_payload_len = MAX_PRINTABLE_CHARACTERS;
 388         fixture.expected_return_value = 0;
 389         fixture.expected_payload_len = 0;
 390         fixture.expected_return_payload = "";
 391         EXECUTE_HEARTBEAT_TEST();
 392         }
 393
 394 #undef EXECUTE_HEARTBEAT_TEST
 395 #undef SETUP_HEARTBEAT_TEST_FIXTURE
 396
 397 int main(int argc, char *argv[])
 398         {
 399         SSL_library_init();
 400         SSL_load_error_strings();
 401
 402         const int num_failed = test_dtls1_not_bleeding() +
 403                         test_dtls1_not_bleeding_empty_payload() +
 404                         test_dtls1_heartbleed() +
 405                         test_dtls1_heartbleed_empty_payload() +
 406                         /* The following test causes an assertion failure at
 407                          * ssl/d1_pkt.c:dtls1_write_bytes() in versions prior to 1.0.1g: */
 408                         (OPENSSL_VERSION_NUMBER >= 0x1000107fL ?
 409                                          test_dtls1_heartbleed_excessive_plaintext_length() : 0) +
 410                         test_tls1_not_bleeding() +
 411                         test_tls1_not_bleeding_empty_payload() +
 412                         test_tls1_heartbleed() +
 413                         test_tls1_heartbleed_empty_payload() +
 414                         0;
 415
 416         ERR_print_errors_fp(stderr);
 417
 418         if (num_failed != 0)
 419                 {
 420                 printf("%d test%s failed\n", num_failed, num_failed != 1 ? "s" : "");
 421                 return EXIT_FAILURE;
 422                 }
 423         return EXIT_SUCCESS;
 424         }