2 * Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (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>
40 #include "../ssl/packet_locl.h"
41 #include "internal/nelem.h"
44 /* For DTLS1_BAD_VER packets the MAC doesn't include the handshake header */
45 #define MAC_OFFSET (DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH)
47 static unsigned char client_random[SSL3_RANDOM_SIZE];
48 static unsigned char server_random[SSL3_RANDOM_SIZE];
50 /* These are all generated locally, sized purely according to our own whim */
51 static unsigned char session_id[32];
52 static unsigned char master_secret[48];
53 static unsigned char cookie[20];
55 /* We've hard-coded the cipher suite; we know it's 104 bytes */
56 static unsigned char key_block[104];
57 #define mac_key (key_block + 20)
58 #define dec_key (key_block + 40)
59 #define enc_key (key_block + 56)
61 static EVP_MD_CTX *handshake_md;
63 static int do_PRF(const void *seed1, int seed1_len,
64 const void *seed2, int seed2_len,
65 const void *seed3, int seed3_len,
66 unsigned char *out, int olen)
68 EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_TLS1_PRF, NULL);
71 /* No error handling. If it all screws up, the test will fail anyway */
72 EVP_PKEY_derive_init(pctx);
73 EVP_PKEY_CTX_set_tls1_prf_md(pctx, EVP_md5_sha1());
74 EVP_PKEY_CTX_set1_tls1_prf_secret(pctx, master_secret, sizeof(master_secret));
75 EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed1, seed1_len);
76 EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed2, seed2_len);
77 EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed3, seed3_len);
78 EVP_PKEY_derive(pctx, out, &outlen);
79 EVP_PKEY_CTX_free(pctx);
83 static SSL_SESSION *client_session(void)
85 static unsigned char session_asn1[] = {
86 0x30, 0x5F, /* SEQUENCE, length 0x5F */
87 0x02, 0x01, 0x01, /* INTEGER, SSL_SESSION_ASN1_VERSION */
88 0x02, 0x02, 0x01, 0x00, /* INTEGER, DTLS1_BAD_VER */
89 0x04, 0x02, 0x00, 0x2F, /* OCTET_STRING, AES128-SHA */
90 0x04, 0x20, /* OCTET_STRING, session id */
91 #define SS_SESSID_OFS 15 /* Session ID goes here */
92 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
93 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
94 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
95 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
96 0x04, 0x30, /* OCTET_STRING, master secret */
97 #define SS_SECRET_OFS 49 /* Master secret goes here */
98 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
99 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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,
105 const unsigned char *p = session_asn1;
107 /* Copy the randomly-generated fields into the above ASN1 */
108 memcpy(session_asn1 + SS_SESSID_OFS, session_id, sizeof(session_id));
109 memcpy(session_asn1 + SS_SECRET_OFS, master_secret, sizeof(master_secret));
111 return d2i_SSL_SESSION(NULL, &p, sizeof(session_asn1));
114 /* Returns 1 for initial ClientHello, 2 for ClientHello with cookie */
115 static int validate_client_hello(BIO *wbio)
120 int cookie_found = 0;
123 len = BIO_get_mem_data(wbio, (char **)&data);
124 if (!PACKET_buf_init(&pkt, data, len))
127 /* Check record header type */
128 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_HANDSHAKE)
131 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
133 /* Skip the rest of the record header */
134 if (!PACKET_forward(&pkt, DTLS1_RT_HEADER_LENGTH - 3))
137 /* Check it's a ClientHello */
138 if (!PACKET_get_1(&pkt, &u) || u != SSL3_MT_CLIENT_HELLO)
140 /* Skip the rest of the handshake message header */
141 if (!PACKET_forward(&pkt, DTLS1_HM_HEADER_LENGTH - 1))
144 /* Check client version */
145 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
149 if (!PACKET_copy_bytes(&pkt, client_random, SSL3_RANDOM_SIZE))
152 /* Check session id length and content */
153 if (!PACKET_get_length_prefixed_1(&pkt, &pkt2) ||
154 !PACKET_equal(&pkt2, session_id, sizeof(session_id)))
158 if (!PACKET_get_length_prefixed_1(&pkt, &pkt2))
160 if (PACKET_remaining(&pkt2)) {
161 if (!PACKET_equal(&pkt2, cookie, sizeof(cookie)))
167 if (!PACKET_get_net_2(&pkt, &u) || !PACKET_forward(&pkt, u))
170 /* Skip compression */
171 if (!PACKET_get_1(&pkt, &u) || !PACKET_forward(&pkt, u))
174 /* Skip extensions */
175 if (!PACKET_get_net_2(&pkt, &u) || !PACKET_forward(&pkt, u))
178 /* Now we are at the end */
179 if (PACKET_remaining(&pkt))
182 /* Update handshake MAC for second ClientHello (with cookie) */
183 if (cookie_found && !EVP_DigestUpdate(handshake_md, data + MAC_OFFSET,
187 (void)BIO_reset(wbio);
189 return 1 + cookie_found;
192 static int send_hello_verify(BIO *rbio)
194 static unsigned char hello_verify[] = {
195 0x16, /* Handshake */
196 0x01, 0x00, /* DTLS1_BAD_VER */
197 0x00, 0x00, /* Epoch 0 */
198 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Seq# 0 */
199 0x00, 0x23, /* Length */
200 0x03, /* Hello Verify */
201 0x00, 0x00, 0x17, /* Length */
202 0x00, 0x00, /* Seq# 0 */
203 0x00, 0x00, 0x00, /* Fragment offset */
204 0x00, 0x00, 0x17, /* Fragment length */
205 0x01, 0x00, /* DTLS1_BAD_VER */
206 0x14, /* Cookie length */
207 #define HV_COOKIE_OFS 28 /* Cookie goes here */
208 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
209 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
210 0x00, 0x00, 0x00, 0x00,
213 memcpy(hello_verify + HV_COOKIE_OFS, cookie, sizeof(cookie));
215 BIO_write(rbio, hello_verify, sizeof(hello_verify));
220 static int send_server_hello(BIO *rbio)
222 static unsigned char server_hello[] = {
223 0x16, /* Handshake */
224 0x01, 0x00, /* DTLS1_BAD_VER */
225 0x00, 0x00, /* Epoch 0 */
226 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, /* Seq# 1 */
227 0x00, 0x52, /* Length */
228 0x02, /* Server Hello */
229 0x00, 0x00, 0x46, /* Length */
230 0x00, 0x01, /* Seq# */
231 0x00, 0x00, 0x00, /* Fragment offset */
232 0x00, 0x00, 0x46, /* Fragment length */
233 0x01, 0x00, /* DTLS1_BAD_VER */
234 #define SH_RANDOM_OFS 27 /* Server random goes here */
235 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
236 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
237 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
238 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
239 0x20, /* Session ID length */
240 #define SH_SESSID_OFS 60 /* Session ID goes here */
241 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
242 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
243 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
244 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
245 0x00, 0x2f, /* Cipher suite AES128-SHA */
246 0x00, /* Compression null */
248 static unsigned char change_cipher_spec[] = {
249 0x14, /* Change Cipher Spec */
250 0x01, 0x00, /* DTLS1_BAD_VER */
251 0x00, 0x00, /* Epoch 0 */
252 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, /* Seq# 2 */
253 0x00, 0x03, /* Length */
254 0x01, 0x00, 0x02, /* Message */
257 memcpy(server_hello + SH_RANDOM_OFS, server_random, sizeof(server_random));
258 memcpy(server_hello + SH_SESSID_OFS, session_id, sizeof(session_id));
260 if (!EVP_DigestUpdate(handshake_md, server_hello + MAC_OFFSET,
261 sizeof(server_hello) - MAC_OFFSET))
264 BIO_write(rbio, server_hello, sizeof(server_hello));
265 BIO_write(rbio, change_cipher_spec, sizeof(change_cipher_spec));
270 /* Create header, HMAC, pad, encrypt and send a record */
271 static int send_record(BIO *rbio, unsigned char type, uint64_t seqnr,
272 const void *msg, size_t len)
274 /* Note that the order of the record header fields on the wire,
275 * and in the HMAC, is different. So we just keep them in separate
276 * variables and handle them individually. */
277 static unsigned char epoch[2] = { 0x00, 0x01 };
278 static unsigned char seq[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
279 static unsigned char ver[2] = { 0x01, 0x00 }; /* DTLS1_BAD_VER */
280 unsigned char lenbytes[2];
282 EVP_CIPHER_CTX *enc_ctx;
283 unsigned char iv[16];
287 seq[0] = (seqnr >> 40) & 0xff;
288 seq[1] = (seqnr >> 32) & 0xff;
289 seq[2] = (seqnr >> 24) & 0xff;
290 seq[3] = (seqnr >> 16) & 0xff;
291 seq[4] = (seqnr >> 8) & 0xff;
292 seq[5] = seqnr & 0xff;
294 pad = 15 - ((len + SHA_DIGEST_LENGTH) % 16);
295 enc = OPENSSL_malloc(len + SHA_DIGEST_LENGTH + 1 + pad);
299 /* Copy record to encryption buffer */
300 memcpy(enc, msg, len);
302 /* Append HMAC to data */
303 ctx = HMAC_CTX_new();
304 HMAC_Init_ex(ctx, mac_key, 20, EVP_sha1(), NULL);
305 HMAC_Update(ctx, epoch, 2);
306 HMAC_Update(ctx, seq, 6);
307 HMAC_Update(ctx, &type, 1);
308 HMAC_Update(ctx, ver, 2); /* Version */
309 lenbytes[0] = (unsigned char)(len >> 8);
310 lenbytes[1] = (unsigned char)(len);
311 HMAC_Update(ctx, lenbytes, 2); /* Length */
312 HMAC_Update(ctx, enc, len); /* Finally the data itself */
313 HMAC_Final(ctx, enc + len, NULL);
316 /* Append padding bytes */
317 len += SHA_DIGEST_LENGTH;
322 /* Generate IV, and encrypt */
323 RAND_bytes(iv, sizeof(iv));
324 enc_ctx = EVP_CIPHER_CTX_new();
325 EVP_CipherInit_ex(enc_ctx, EVP_aes_128_cbc(), NULL, enc_key, iv, 1);
326 EVP_Cipher(enc_ctx, enc, enc, len);
327 EVP_CIPHER_CTX_free(enc_ctx);
329 /* Finally write header (from fragmented variables), IV and encrypted record */
330 BIO_write(rbio, &type, 1);
331 BIO_write(rbio, ver, 2);
332 BIO_write(rbio, epoch, 2);
333 BIO_write(rbio, seq, 6);
334 lenbytes[0] = (unsigned char)((len + sizeof(iv)) >> 8);
335 lenbytes[1] = (unsigned char)(len + sizeof(iv));
336 BIO_write(rbio, lenbytes, 2);
338 BIO_write(rbio, iv, sizeof(iv));
339 BIO_write(rbio, enc, len);
345 static int send_finished(SSL *s, BIO *rbio)
347 static unsigned char finished_msg[DTLS1_HM_HEADER_LENGTH +
348 TLS1_FINISH_MAC_LENGTH] = {
350 0x00, 0x00, 0x0c, /* Length */
351 0x00, 0x03, /* Seq# 3 */
352 0x00, 0x00, 0x00, /* Fragment offset */
353 0x00, 0x00, 0x0c, /* Fragment length */
354 /* Finished MAC (12 bytes) */
356 unsigned char handshake_hash[EVP_MAX_MD_SIZE];
358 /* Derive key material */
359 do_PRF(TLS_MD_KEY_EXPANSION_CONST, TLS_MD_KEY_EXPANSION_CONST_SIZE,
360 server_random, SSL3_RANDOM_SIZE,
361 client_random, SSL3_RANDOM_SIZE,
362 key_block, sizeof(key_block));
364 /* Generate Finished MAC */
365 if (!EVP_DigestFinal_ex(handshake_md, handshake_hash, NULL))
368 do_PRF(TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
369 handshake_hash, EVP_MD_CTX_size(handshake_md),
371 finished_msg + DTLS1_HM_HEADER_LENGTH, TLS1_FINISH_MAC_LENGTH);
373 return send_record(rbio, SSL3_RT_HANDSHAKE, 0,
374 finished_msg, sizeof(finished_msg));
377 static int validate_ccs(BIO *wbio)
384 len = BIO_get_mem_data(wbio, (char **)&data);
385 if (!PACKET_buf_init(&pkt, data, len))
388 /* Check record header type */
389 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_CHANGE_CIPHER_SPEC)
392 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
394 /* Skip the rest of the record header */
395 if (!PACKET_forward(&pkt, DTLS1_RT_HEADER_LENGTH - 3))
398 /* Check ChangeCipherSpec message */
399 if (!PACKET_get_1(&pkt, &u) || u != SSL3_MT_CCS)
401 /* A DTLS1_BAD_VER ChangeCipherSpec also contains the
402 * handshake sequence number (which is 2 here) */
403 if (!PACKET_get_net_2(&pkt, &u) || u != 0x0002)
406 /* Now check the Finished packet */
407 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_HANDSHAKE)
409 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
412 /* Check epoch is now 1 */
413 if (!PACKET_get_net_2(&pkt, &u) || u != 0x0001)
416 /* That'll do for now. If OpenSSL accepted *our* Finished packet
417 * then it's evidently remembered that DTLS1_BAD_VER doesn't
418 * include the handshake header in the MAC. There's not a lot of
419 * point in implementing decryption here, just to check that it
420 * continues to get it right for one more packet. */
425 #define NODROP(x) { x##UL, 0 }
426 #define DROP(x) { x##UL, 1 }
432 NODROP(1), NODROP(3), NODROP(2),
433 NODROP(0x1234), NODROP(0x1230), NODROP(0x1235),
434 NODROP(0xffff), NODROP(0x10001), NODROP(0xfffe), NODROP(0x10000),
435 DROP(0x10001), DROP(0xff), NODROP(0x100000), NODROP(0x800000), NODROP(0x7fffe1),
436 NODROP(0xffffff), NODROP(0x1000000), NODROP(0xfffffe), DROP(0xffffff), NODROP(0x1000010),
437 NODROP(0xfffffd), NODROP(0x1000011), DROP(0x12), NODROP(0x1000012),
438 NODROP(0x1ffffff), NODROP(0x2000000), DROP(0x1ff00fe), NODROP(0x2000001),
439 NODROP(0x20fffff), NODROP(0x2105500), DROP(0x20ffffe), NODROP(0x21054ff),
440 NODROP(0x211ffff), DROP(0x2110000), NODROP(0x2120000)
441 /* The last test should be NODROP, because a DROP wouldn't get tested. */
444 static int test_bad_dtls(void)
446 SSL_SESSION *sess = NULL;
456 RAND_bytes(session_id, sizeof(session_id));
457 RAND_bytes(master_secret, sizeof(master_secret));
458 RAND_bytes(cookie, sizeof(cookie));
459 RAND_bytes(server_random + 4, sizeof(server_random) - 4);
462 memcpy(server_random, &now, sizeof(now));
464 sess = client_session();
468 handshake_md = EVP_MD_CTX_new();
469 if (!TEST_ptr(handshake_md)
470 || !TEST_true(EVP_DigestInit_ex(handshake_md, EVP_md5_sha1(),
474 ctx = SSL_CTX_new(DTLS_client_method());
476 || !TEST_true(SSL_CTX_set_min_proto_version(ctx, DTLS1_BAD_VER))
477 || !TEST_true(SSL_CTX_set_max_proto_version(ctx, DTLS1_BAD_VER))
478 || !TEST_true(SSL_CTX_set_cipher_list(ctx, "AES128-SHA")))
483 || !TEST_true(SSL_set_session(con, sess)))
485 SSL_SESSION_free(sess);
487 rbio = BIO_new(BIO_s_mem());
488 wbio = BIO_new(BIO_s_mem());
494 SSL_set_bio(con, rbio, wbio);
496 if (!TEST_true(BIO_up_ref(rbio))) {
498 * We can't up-ref but we assigned ownership to con, so we shouldn't
499 * free in the "end" block
505 if (!TEST_true(BIO_up_ref(wbio))) {
510 SSL_set_connect_state(con);
512 /* Send initial ClientHello */
513 ret = SSL_do_handshake(con);
514 if (!TEST_int_le(ret, 0)
515 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
516 || !TEST_int_eq(validate_client_hello(wbio), 1)
517 || !TEST_true(send_hello_verify(rbio)))
520 ret = SSL_do_handshake(con);
521 if (!TEST_int_le(ret, 0)
522 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
523 || !TEST_int_eq(validate_client_hello(wbio), 2)
524 || !TEST_true(send_server_hello(rbio)))
527 ret = SSL_do_handshake(con);
528 if (!TEST_int_le(ret, 0)
529 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
530 || !TEST_true(send_finished(con, rbio)))
533 ret = SSL_do_handshake(con);
534 if (!TEST_int_gt(ret, 0)
535 || !TEST_true(validate_ccs(wbio)))
538 /* While we're here and crafting packets by hand, we might as well do a
539 bit of a stress test on the DTLS record replay handling. Not Cisco-DTLS
540 specific but useful anyway for the general case. It's been broken
541 before, and in fact was broken even for a basic 0, 2, 1 test case
542 when this test was first added.... */
543 for (i = 0; i < (int)OSSL_NELEM(tests); i++) {
544 uint64_t recv_buf[2];
546 if (!TEST_true(send_record(rbio, SSL3_RT_APPLICATION_DATA, tests[i].seq,
547 &tests[i].seq, sizeof(uint64_t)))) {
548 TEST_error("Failed to send data seq #0x%x%08x (%d)\n",
549 (unsigned int)(tests[i].seq >> 32), (unsigned int)tests[i].seq, i);
556 ret = SSL_read(con, recv_buf, 2 * sizeof(uint64_t));
557 if (!TEST_int_eq(ret, (int)sizeof(uint64_t))) {
558 TEST_error("SSL_read failed or wrong size on seq#0x%x%08x (%d)\n",
559 (unsigned int)(tests[i].seq >> 32), (unsigned int)tests[i].seq, i);
562 if (!TEST_true(recv_buf[0] == tests[i].seq))
566 /* The last test cannot be DROP() */
567 if (!TEST_false(tests[i-1].drop))
577 EVP_MD_CTX_free(handshake_md);
582 int setup_tests(void)
584 ADD_TEST(test_bad_dtls);