2 * Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 * Unit test for Cisco DTLS1_BAD_VER session resume, as used by
12 * AnyConnect VPN protocol.
14 * This is designed to exercise the code paths in
15 * http://git.infradead.org/users/dwmw2/openconnect.git/blob/HEAD:/dtls.c
16 * which have frequently been affected by regressions in DTLS1_BAD_VER
19 * Note that unlike other SSL tests, we don't test against our own SSL
20 * server method. Firstly because we don't have one; we *only* support
21 * DTLS1_BAD_VER as a client. And secondly because even if that were
22 * fixed up it's the wrong thing to test against — because if changes
23 * are made in generic DTLS code which don't take DTLS1_BAD_VER into
24 * account, there's plenty of scope for making those changes such that
25 * they break *both* the client and the server in the same way.
27 * So we handle the server side manually. In a session resume there isn't
28 * much to be done anyway.
32 #include <openssl/opensslconf.h>
33 #include <openssl/bio.h>
34 #include <openssl/crypto.h>
35 #include <openssl/evp.h>
36 #include <openssl/ssl.h>
37 #include <openssl/err.h>
38 #include <openssl/rand.h>
39 #include <openssl/kdf.h>
41 #include "../ssl/packet_locl.h"
42 #include "../e_os.h" /* for OSSL_NELEM() */
46 /* For DTLS1_BAD_VER packets the MAC doesn't include the handshake header */
47 #define MAC_OFFSET (DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH)
49 static unsigned char client_random[SSL3_RANDOM_SIZE];
50 static unsigned char server_random[SSL3_RANDOM_SIZE];
52 /* These are all generated locally, sized purely according to our own whim */
53 static unsigned char session_id[32];
54 static unsigned char master_secret[48];
55 static unsigned char cookie[20];
57 /* We've hard-coded the cipher suite; we know it's 104 bytes */
58 static unsigned char key_block[104];
59 #define mac_key (key_block + 20)
60 #define dec_key (key_block + 40)
61 #define enc_key (key_block + 56)
63 static EVP_MD_CTX *handshake_md;
65 static int do_PRF(const void *seed1, int seed1_len,
66 const void *seed2, int seed2_len,
67 const void *seed3, int seed3_len,
68 unsigned char *out, int olen)
70 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_TLS1_PRF, NULL);
73 /* No error handling. If it all screws up, the test will fail anyway */
74 EVP_PKEY_derive_init(pctx);
75 EVP_PKEY_CTX_set_tls1_prf_md(pctx, EVP_md5_sha1());
76 EVP_PKEY_CTX_set1_tls1_prf_secret(pctx, master_secret, sizeof(master_secret));
77 EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed1, seed1_len);
78 EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed2, seed2_len);
79 EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed3, seed3_len);
80 EVP_PKEY_derive(pctx, out, &outlen);
81 EVP_PKEY_CTX_free(pctx);
85 static SSL_SESSION *client_session(void)
87 static unsigned char session_asn1[] = {
88 0x30, 0x5F, /* SEQUENCE, length 0x5F */
89 0x02, 0x01, 0x01, /* INTEGER, SSL_SESSION_ASN1_VERSION */
90 0x02, 0x02, 0x01, 0x00, /* INTEGER, DTLS1_BAD_VER */
91 0x04, 0x02, 0x00, 0x2F, /* OCTET_STRING, AES128-SHA */
92 0x04, 0x20, /* OCTET_STRING, session id */
93 #define SS_SESSID_OFS 15 /* Session ID goes here */
94 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
95 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
96 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
97 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
98 0x04, 0x30, /* OCTET_STRING, master secret */
99 #define SS_SECRET_OFS 49 /* Master secret goes here */
100 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
101 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
102 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
103 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
104 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
105 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
107 const unsigned char *p = session_asn1;
109 /* Copy the randomly-generated fields into the above ASN1 */
110 memcpy(session_asn1 + SS_SESSID_OFS, session_id, sizeof(session_id));
111 memcpy(session_asn1 + SS_SECRET_OFS, master_secret, sizeof(master_secret));
113 return d2i_SSL_SESSION(NULL, &p, sizeof(session_asn1));
116 /* Returns 1 for initial ClientHello, 2 for ClientHello with cookie */
117 static int validate_client_hello(BIO *wbio)
122 int cookie_found = 0;
125 len = BIO_get_mem_data(wbio, (char **)&data);
126 if (!PACKET_buf_init(&pkt, data, len))
129 /* Check record header type */
130 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_HANDSHAKE)
133 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
135 /* Skip the rest of the record header */
136 if (!PACKET_forward(&pkt, DTLS1_RT_HEADER_LENGTH - 3))
139 /* Check it's a ClientHello */
140 if (!PACKET_get_1(&pkt, &u) || u != SSL3_MT_CLIENT_HELLO)
142 /* Skip the rest of the handshake message header */
143 if (!PACKET_forward(&pkt, DTLS1_HM_HEADER_LENGTH - 1))
146 /* Check client version */
147 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
151 if (!PACKET_copy_bytes(&pkt, client_random, SSL3_RANDOM_SIZE))
154 /* Check session id length and content */
155 if (!PACKET_get_length_prefixed_1(&pkt, &pkt2) ||
156 !PACKET_equal(&pkt2, session_id, sizeof(session_id)))
160 if (!PACKET_get_length_prefixed_1(&pkt, &pkt2))
162 if (PACKET_remaining(&pkt2)) {
163 if (!PACKET_equal(&pkt2, cookie, sizeof(cookie)))
169 if (!PACKET_get_net_2(&pkt, &u) || !PACKET_forward(&pkt, u))
172 /* Skip compression */
173 if (!PACKET_get_1(&pkt, &u) || !PACKET_forward(&pkt, u))
176 /* Skip extensions */
177 if (!PACKET_get_net_2(&pkt, &u) || !PACKET_forward(&pkt, u))
180 /* Now we are at the end */
181 if (PACKET_remaining(&pkt))
184 /* Update handshake MAC for second ClientHello (with cookie) */
185 if (cookie_found && !EVP_DigestUpdate(handshake_md, data + MAC_OFFSET,
189 (void)BIO_reset(wbio);
191 return 1 + cookie_found;
194 static int send_hello_verify(BIO *rbio)
196 static unsigned char hello_verify[] = {
197 0x16, /* Handshake */
198 0x01, 0x00, /* DTLS1_BAD_VER */
199 0x00, 0x00, /* Epoch 0 */
200 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Seq# 0 */
201 0x00, 0x23, /* Length */
202 0x03, /* Hello Verify */
203 0x00, 0x00, 0x17, /* Length */
204 0x00, 0x00, /* Seq# 0 */
205 0x00, 0x00, 0x00, /* Fragment offset */
206 0x00, 0x00, 0x17, /* Fragment length */
207 0x01, 0x00, /* DTLS1_BAD_VER */
208 0x14, /* Cookie length */
209 #define HV_COOKIE_OFS 28 /* Cookie goes here */
210 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
211 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
212 0x00, 0x00, 0x00, 0x00,
215 memcpy(hello_verify + HV_COOKIE_OFS, cookie, sizeof(cookie));
217 BIO_write(rbio, hello_verify, sizeof(hello_verify));
222 static int send_server_hello(BIO *rbio)
224 static unsigned char server_hello[] = {
225 0x16, /* Handshake */
226 0x01, 0x00, /* DTLS1_BAD_VER */
227 0x00, 0x00, /* Epoch 0 */
228 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, /* Seq# 1 */
229 0x00, 0x52, /* Length */
230 0x02, /* Server Hello */
231 0x00, 0x00, 0x46, /* Length */
232 0x00, 0x01, /* Seq# */
233 0x00, 0x00, 0x00, /* Fragment offset */
234 0x00, 0x00, 0x46, /* Fragment length */
235 0x01, 0x00, /* DTLS1_BAD_VER */
236 #define SH_RANDOM_OFS 27 /* Server random goes here */
237 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
238 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
239 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
240 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
241 0x20, /* Session ID length */
242 #define SH_SESSID_OFS 60 /* Session ID goes here */
243 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
244 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
245 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
246 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
247 0x00, 0x2f, /* Cipher suite AES128-SHA */
248 0x00, /* Compression null */
250 static unsigned char change_cipher_spec[] = {
251 0x14, /* Change Cipher Spec */
252 0x01, 0x00, /* DTLS1_BAD_VER */
253 0x00, 0x00, /* Epoch 0 */
254 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, /* Seq# 2 */
255 0x00, 0x03, /* Length */
256 0x01, 0x00, 0x02, /* Message */
259 memcpy(server_hello + SH_RANDOM_OFS, server_random, sizeof(server_random));
260 memcpy(server_hello + SH_SESSID_OFS, session_id, sizeof(session_id));
262 if (!EVP_DigestUpdate(handshake_md, server_hello + MAC_OFFSET,
263 sizeof(server_hello) - MAC_OFFSET))
266 BIO_write(rbio, server_hello, sizeof(server_hello));
267 BIO_write(rbio, change_cipher_spec, sizeof(change_cipher_spec));
272 /* Create header, HMAC, pad, encrypt and send a record */
273 static int send_record(BIO *rbio, unsigned char type, uint64_t seqnr,
274 const void *msg, size_t len)
276 /* Note that the order of the record header fields on the wire,
277 * and in the HMAC, is different. So we just keep them in separate
278 * variables and handle them individually. */
279 static unsigned char epoch[2] = { 0x00, 0x01 };
280 static unsigned char seq[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
281 static unsigned char ver[2] = { 0x01, 0x00 }; /* DTLS1_BAD_VER */
282 unsigned char lenbytes[2];
284 EVP_CIPHER_CTX *enc_ctx;
285 unsigned char iv[16];
289 seq[0] = (seqnr >> 40) & 0xff;
290 seq[1] = (seqnr >> 32) & 0xff;
291 seq[2] = (seqnr >> 24) & 0xff;
292 seq[3] = (seqnr >> 16) & 0xff;
293 seq[4] = (seqnr >> 8) & 0xff;
294 seq[5] = seqnr & 0xff;
296 pad = 15 - ((len + SHA_DIGEST_LENGTH) % 16);
297 enc = OPENSSL_malloc(len + SHA_DIGEST_LENGTH + 1 + pad);
301 /* Copy record to encryption buffer */
302 memcpy(enc, msg, len);
304 /* Append HMAC to data */
305 ctx = HMAC_CTX_new();
306 HMAC_Init_ex(ctx, mac_key, 20, EVP_sha1(), NULL);
307 HMAC_Update(ctx, epoch, 2);
308 HMAC_Update(ctx, seq, 6);
309 HMAC_Update(ctx, &type, 1);
310 HMAC_Update(ctx, ver, 2); /* Version */
311 lenbytes[0] = len >> 8;
312 lenbytes[1] = len & 0xff;
313 HMAC_Update(ctx, lenbytes, 2); /* Length */
314 HMAC_Update(ctx, enc, len); /* Finally the data itself */
315 HMAC_Final(ctx, enc + len, NULL);
318 /* Append padding bytes */
319 len += SHA_DIGEST_LENGTH;
324 /* Generate IV, and encrypt */
325 RAND_bytes(iv, sizeof(iv));
326 enc_ctx = EVP_CIPHER_CTX_new();
327 EVP_CipherInit_ex(enc_ctx, EVP_aes_128_cbc(), NULL, enc_key, iv, 1);
328 EVP_Cipher(enc_ctx, enc, enc, len);
329 EVP_CIPHER_CTX_free(enc_ctx);
331 /* Finally write header (from fragmented variables), IV and encrypted record */
332 BIO_write(rbio, &type, 1);
333 BIO_write(rbio, ver, 2);
334 BIO_write(rbio, epoch, 2);
335 BIO_write(rbio, seq, 6);
336 lenbytes[0] = (len + sizeof(iv)) >> 8;
337 lenbytes[1] = (len + sizeof(iv)) & 0xff;
338 BIO_write(rbio, lenbytes, 2);
340 BIO_write(rbio, iv, sizeof(iv));
341 BIO_write(rbio, enc, len);
347 static int send_finished(SSL *s, BIO *rbio)
349 static unsigned char finished_msg[DTLS1_HM_HEADER_LENGTH +
350 TLS1_FINISH_MAC_LENGTH] = {
352 0x00, 0x00, 0x0c, /* Length */
353 0x00, 0x03, /* Seq# 3 */
354 0x00, 0x00, 0x00, /* Fragment offset */
355 0x00, 0x00, 0x0c, /* Fragment length */
356 /* Finished MAC (12 bytes) */
358 unsigned char handshake_hash[EVP_MAX_MD_SIZE];
360 /* Derive key material */
361 do_PRF(TLS_MD_KEY_EXPANSION_CONST, TLS_MD_KEY_EXPANSION_CONST_SIZE,
362 server_random, SSL3_RANDOM_SIZE,
363 client_random, SSL3_RANDOM_SIZE,
364 key_block, sizeof(key_block));
366 /* Generate Finished MAC */
367 if (!EVP_DigestFinal_ex(handshake_md, handshake_hash, NULL))
370 do_PRF(TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
371 handshake_hash, EVP_MD_CTX_size(handshake_md),
373 finished_msg + DTLS1_HM_HEADER_LENGTH, TLS1_FINISH_MAC_LENGTH);
375 return send_record(rbio, SSL3_RT_HANDSHAKE, 0,
376 finished_msg, sizeof(finished_msg));
379 static int validate_ccs(BIO *wbio)
386 len = BIO_get_mem_data(wbio, (char **)&data);
387 if (!PACKET_buf_init(&pkt, data, len))
390 /* Check record header type */
391 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_CHANGE_CIPHER_SPEC)
394 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
396 /* Skip the rest of the record header */
397 if (!PACKET_forward(&pkt, DTLS1_RT_HEADER_LENGTH - 3))
400 /* Check ChangeCipherSpec message */
401 if (!PACKET_get_1(&pkt, &u) || u != SSL3_MT_CCS)
403 /* A DTLS1_BAD_VER ChangeCipherSpec also contains the
404 * handshake sequence number (which is 2 here) */
405 if (!PACKET_get_net_2(&pkt, &u) || u != 0x0002)
408 /* Now check the Finished packet */
409 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_HANDSHAKE)
411 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
414 /* Check epoch is now 1 */
415 if (!PACKET_get_net_2(&pkt, &u) || u != 0x0001)
418 /* That'll do for now. If OpenSSL accepted *our* Finished packet
419 * then it's evidently remembered that DTLS1_BAD_VER doesn't
420 * include the handshake header in the MAC. There's not a lot of
421 * point in implementing decryption here, just to check that it
422 * continues to get it right for one more packet. */
427 #define NODROP(x) { x##UL, 0 }
428 #define DROP(x) { x##UL, 1 }
434 NODROP(1), NODROP(3), NODROP(2),
435 NODROP(0x1234), NODROP(0x1230), NODROP(0x1235),
436 NODROP(0xffff), NODROP(0x10001), NODROP(0xfffe), NODROP(0x10000),
437 DROP(0x10001), DROP(0xff), NODROP(0x100000), NODROP(0x800000), NODROP(0x7fffe1),
438 NODROP(0xffffff), NODROP(0x1000000), NODROP(0xfffffe), DROP(0xffffff), NODROP(0x1000010),
439 NODROP(0xfffffd), NODROP(0x1000011), DROP(0x12), NODROP(0x1000012),
440 NODROP(0x1ffffff), NODROP(0x2000000), DROP(0x1ff00fe), NODROP(0x2000001),
441 NODROP(0x20fffff), NODROP(0x2105500), DROP(0x20ffffe), NODROP(0x21054ff),
442 NODROP(0x211ffff), DROP(0x2110000), NODROP(0x2120000)
443 /* The last test should be NODROP, because a DROP wouldn't get tested. */
446 static int test_bad_dtls(void)
448 SSL_SESSION *sess = NULL;
458 RAND_bytes(session_id, sizeof(session_id));
459 RAND_bytes(master_secret, sizeof(master_secret));
460 RAND_bytes(cookie, sizeof(cookie));
461 RAND_bytes(server_random + 4, sizeof(server_random) - 4);
464 memcpy(server_random, &now, sizeof(now));
466 sess = client_session();
470 handshake_md = EVP_MD_CTX_new();
471 if (!TEST_ptr(handshake_md)
472 || !TEST_true(EVP_DigestInit_ex(handshake_md, EVP_md5_sha1(),
476 ctx = SSL_CTX_new(DTLS_client_method());
478 || !TEST_true(SSL_CTX_set_min_proto_version(ctx, DTLS1_BAD_VER))
479 || !TEST_true(SSL_CTX_set_max_proto_version(ctx, DTLS1_BAD_VER))
480 || !TEST_true(SSL_CTX_set_cipher_list(ctx, "AES128-SHA")))
485 || !TEST_true(SSL_set_session(con, sess)))
487 SSL_SESSION_free(sess);
489 rbio = BIO_new(BIO_s_mem());
490 wbio = BIO_new(BIO_s_mem());
496 SSL_set_bio(con, rbio, wbio);
498 if (!TEST_true(BIO_up_ref(rbio))) {
500 * We can't up-ref but we assigned ownership to con, so we shouldn't
501 * free in the "end" block
507 if (!TEST_true(BIO_up_ref(wbio))) {
512 SSL_set_connect_state(con);
514 /* Send initial ClientHello */
515 ret = SSL_do_handshake(con);
516 if (!TEST_int_le(ret, 0)
517 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
518 || !TEST_int_eq(validate_client_hello(wbio), 1)
519 || !TEST_true(send_hello_verify(rbio)))
522 ret = SSL_do_handshake(con);
523 if (!TEST_int_le(ret, 0)
524 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
525 || !TEST_int_eq(validate_client_hello(wbio), 2)
526 || !TEST_true(send_server_hello(rbio)))
529 ret = SSL_do_handshake(con);
530 if (!TEST_int_le(ret, 0)
531 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
532 || !TEST_true(send_finished(con, rbio)))
535 ret = SSL_do_handshake(con);
536 if (!TEST_int_gt(ret, 0)
537 || !TEST_true(validate_ccs(wbio)))
540 /* While we're here and crafting packets by hand, we might as well do a
541 bit of a stress test on the DTLS record replay handling. Not Cisco-DTLS
542 specific but useful anyway for the general case. It's been broken
543 before, and in fact was broken even for a basic 0, 2, 1 test case
544 when this test was first added.... */
545 for (i = 0; i < (int)OSSL_NELEM(tests); i++) {
546 uint64_t recv_buf[2];
548 if (!TEST_true(send_record(rbio, SSL3_RT_APPLICATION_DATA, tests[i].seq,
549 &tests[i].seq, sizeof(uint64_t)))) {
550 TEST_error("Failed to send data seq #0x%x%08x (%d)\n",
551 (unsigned int)(tests[i].seq >> 32), (unsigned int)tests[i].seq, i);
558 ret = SSL_read(con, recv_buf, 2 * sizeof(uint64_t));
559 if (!TEST_int_eq(ret, (int)sizeof(uint64_t))) {
560 TEST_error("SSL_read failed or wrong size on seq#0x%x%08x (%d)\n",
561 (unsigned int)(tests[i].seq >> 32), (unsigned int)tests[i].seq, i);
564 if (!TEST_true(recv_buf[0] == tests[i].seq))
568 /* The last test cannot be DROP() */
569 if (!TEST_false(tests[i-1].drop))
579 EVP_MD_CTX_free(handshake_md);
584 void register_tests(void)
586 ADD_TEST(test_bad_dtls);