2 * Copyright 2016-2021 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/core_names.h>
33 #include <openssl/params.h>
34 #include <openssl/opensslconf.h>
35 #include <openssl/bio.h>
36 #include <openssl/crypto.h>
37 #include <openssl/evp.h>
38 #include <openssl/ssl.h>
39 #include <openssl/err.h>
40 #include <openssl/rand.h>
41 #include <openssl/kdf.h>
42 #include "internal/packet.h"
43 #include "internal/nelem.h"
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 if ((len = BIO_get_mem_data(wbio, (char **)&data)) < 0)
127 if (!PACKET_buf_init(&pkt, data, len))
130 /* Check record header type */
131 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_HANDSHAKE)
134 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
136 /* Skip the rest of the record header */
137 if (!PACKET_forward(&pkt, DTLS1_RT_HEADER_LENGTH - 3))
140 /* Check it's a ClientHello */
141 if (!PACKET_get_1(&pkt, &u) || u != SSL3_MT_CLIENT_HELLO)
143 /* Skip the rest of the handshake message header */
144 if (!PACKET_forward(&pkt, DTLS1_HM_HEADER_LENGTH - 1))
147 /* Check client version */
148 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
152 if (!PACKET_copy_bytes(&pkt, client_random, SSL3_RANDOM_SIZE))
155 /* Check session id length and content */
156 if (!PACKET_get_length_prefixed_1(&pkt, &pkt2) ||
157 !PACKET_equal(&pkt2, session_id, sizeof(session_id)))
161 if (!PACKET_get_length_prefixed_1(&pkt, &pkt2))
163 if (PACKET_remaining(&pkt2)) {
164 if (!PACKET_equal(&pkt2, cookie, sizeof(cookie)))
170 if (!PACKET_get_net_2(&pkt, &u) || !PACKET_forward(&pkt, u))
173 /* Skip compression */
174 if (!PACKET_get_1(&pkt, &u) || !PACKET_forward(&pkt, u))
177 /* Skip extensions */
178 if (!PACKET_get_net_2(&pkt, &u) || !PACKET_forward(&pkt, u))
181 /* Now we are at the end */
182 if (PACKET_remaining(&pkt))
185 /* Update handshake MAC for second ClientHello (with cookie) */
186 if (cookie_found && !EVP_DigestUpdate(handshake_md, data + MAC_OFFSET,
190 (void)BIO_reset(wbio);
192 return 1 + cookie_found;
195 static int send_hello_verify(BIO *rbio)
197 static unsigned char hello_verify[] = {
198 0x16, /* Handshake */
199 0x01, 0x00, /* DTLS1_BAD_VER */
200 0x00, 0x00, /* Epoch 0 */
201 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Seq# 0 */
202 0x00, 0x23, /* Length */
203 0x03, /* Hello Verify */
204 0x00, 0x00, 0x17, /* Length */
205 0x00, 0x00, /* Seq# 0 */
206 0x00, 0x00, 0x00, /* Fragment offset */
207 0x00, 0x00, 0x17, /* Fragment length */
208 0x01, 0x00, /* DTLS1_BAD_VER */
209 0x14, /* Cookie length */
210 #define HV_COOKIE_OFS 28 /* Cookie goes here */
211 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
212 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
213 0x00, 0x00, 0x00, 0x00,
216 memcpy(hello_verify + HV_COOKIE_OFS, cookie, sizeof(cookie));
218 BIO_write(rbio, hello_verify, sizeof(hello_verify));
223 static int send_server_hello(BIO *rbio)
225 static unsigned char server_hello[] = {
226 0x16, /* Handshake */
227 0x01, 0x00, /* DTLS1_BAD_VER */
228 0x00, 0x00, /* Epoch 0 */
229 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, /* Seq# 1 */
230 0x00, 0x52, /* Length */
231 0x02, /* Server Hello */
232 0x00, 0x00, 0x46, /* Length */
233 0x00, 0x01, /* Seq# */
234 0x00, 0x00, 0x00, /* Fragment offset */
235 0x00, 0x00, 0x46, /* Fragment length */
236 0x01, 0x00, /* DTLS1_BAD_VER */
237 #define SH_RANDOM_OFS 27 /* Server random goes here */
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 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
242 0x20, /* Session ID length */
243 #define SH_SESSID_OFS 60 /* Session ID goes here */
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, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
248 0x00, 0x2f, /* Cipher suite AES128-SHA */
249 0x00, /* Compression null */
251 static unsigned char change_cipher_spec[] = {
252 0x14, /* Change Cipher Spec */
253 0x01, 0x00, /* DTLS1_BAD_VER */
254 0x00, 0x00, /* Epoch 0 */
255 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, /* Seq# 2 */
256 0x00, 0x03, /* Length */
257 0x01, 0x00, 0x02, /* Message */
260 memcpy(server_hello + SH_RANDOM_OFS, server_random, sizeof(server_random));
261 memcpy(server_hello + SH_SESSID_OFS, session_id, sizeof(session_id));
263 if (!EVP_DigestUpdate(handshake_md, server_hello + MAC_OFFSET,
264 sizeof(server_hello) - MAC_OFFSET))
267 BIO_write(rbio, server_hello, sizeof(server_hello));
268 BIO_write(rbio, change_cipher_spec, sizeof(change_cipher_spec));
273 /* Create header, HMAC, pad, encrypt and send a record */
274 static int send_record(BIO *rbio, unsigned char type, uint64_t seqnr,
275 const void *msg, size_t len)
277 /* Note that the order of the record header fields on the wire,
278 * and in the HMAC, is different. So we just keep them in separate
279 * variables and handle them individually. */
280 static unsigned char epoch[2] = { 0x00, 0x01 };
281 static unsigned char seq[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
282 static unsigned char ver[2] = { 0x01, 0x00 }; /* DTLS1_BAD_VER */
283 unsigned char lenbytes[2];
284 EVP_MAC *hmac = NULL;
285 EVP_MAC_CTX *ctx = NULL;
286 EVP_CIPHER_CTX *enc_ctx = NULL;
287 unsigned char iv[16];
290 OSSL_PARAM params[2];
293 seq[0] = (seqnr >> 40) & 0xff;
294 seq[1] = (seqnr >> 32) & 0xff;
295 seq[2] = (seqnr >> 24) & 0xff;
296 seq[3] = (seqnr >> 16) & 0xff;
297 seq[4] = (seqnr >> 8) & 0xff;
298 seq[5] = seqnr & 0xff;
300 pad = 15 - ((len + SHA_DIGEST_LENGTH) % 16);
301 enc = OPENSSL_malloc(len + SHA_DIGEST_LENGTH + 1 + pad);
305 /* Copy record to encryption buffer */
306 memcpy(enc, msg, len);
308 /* Append HMAC to data */
309 if (!TEST_ptr(hmac = EVP_MAC_fetch(NULL, "HMAC", NULL))
310 || !TEST_ptr(ctx = EVP_MAC_CTX_new(hmac)))
312 params[0] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
314 params[1] = OSSL_PARAM_construct_end();
315 lenbytes[0] = (unsigned char)(len >> 8);
316 lenbytes[1] = (unsigned char)(len);
317 if (!EVP_MAC_init(ctx, mac_key, 20, params)
318 || !EVP_MAC_update(ctx, epoch, 2)
319 || !EVP_MAC_update(ctx, seq, 6)
320 || !EVP_MAC_update(ctx, &type, 1)
321 || !EVP_MAC_update(ctx, ver, 2) /* Version */
322 || !EVP_MAC_update(ctx, lenbytes, 2) /* Length */
323 || !EVP_MAC_update(ctx, enc, len) /* Finally the data itself */
324 || !EVP_MAC_final(ctx, enc + len, NULL, SHA_DIGEST_LENGTH))
327 /* Append padding bytes */
328 len += SHA_DIGEST_LENGTH;
333 /* Generate IV, and encrypt */
334 if (!TEST_int_gt(RAND_bytes(iv, sizeof(iv)), 0)
335 || !TEST_ptr(enc_ctx = EVP_CIPHER_CTX_new())
336 || !TEST_true(EVP_CipherInit_ex(enc_ctx, EVP_aes_128_cbc(), NULL,
338 || !TEST_int_ge(EVP_Cipher(enc_ctx, enc, enc, len), 0))
341 /* Finally write header (from fragmented variables), IV and encrypted record */
342 BIO_write(rbio, &type, 1);
343 BIO_write(rbio, ver, 2);
344 BIO_write(rbio, epoch, 2);
345 BIO_write(rbio, seq, 6);
346 lenbytes[0] = (unsigned char)((len + sizeof(iv)) >> 8);
347 lenbytes[1] = (unsigned char)(len + sizeof(iv));
348 BIO_write(rbio, lenbytes, 2);
350 BIO_write(rbio, iv, sizeof(iv));
351 BIO_write(rbio, enc, len);
355 EVP_MAC_CTX_free(ctx);
356 EVP_CIPHER_CTX_free(enc_ctx);
361 static int send_finished(SSL *s, BIO *rbio)
363 static unsigned char finished_msg[DTLS1_HM_HEADER_LENGTH +
364 TLS1_FINISH_MAC_LENGTH] = {
366 0x00, 0x00, 0x0c, /* Length */
367 0x00, 0x03, /* Seq# 3 */
368 0x00, 0x00, 0x00, /* Fragment offset */
369 0x00, 0x00, 0x0c, /* Fragment length */
370 /* Finished MAC (12 bytes) */
372 unsigned char handshake_hash[EVP_MAX_MD_SIZE];
375 /* Derive key material */
376 do_PRF(TLS_MD_KEY_EXPANSION_CONST, TLS_MD_KEY_EXPANSION_CONST_SIZE,
377 server_random, SSL3_RANDOM_SIZE,
378 client_random, SSL3_RANDOM_SIZE,
379 key_block, sizeof(key_block));
381 /* Generate Finished MAC */
382 if (!EVP_DigestFinal_ex(handshake_md, handshake_hash, NULL))
385 md_size = EVP_MD_CTX_get_size(handshake_md);
388 do_PRF(TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
389 handshake_hash, md_size,
391 finished_msg + DTLS1_HM_HEADER_LENGTH, TLS1_FINISH_MAC_LENGTH);
393 return send_record(rbio, SSL3_RT_HANDSHAKE, 0,
394 finished_msg, sizeof(finished_msg));
397 static int validate_ccs(BIO *wbio)
404 len = BIO_get_mem_data(wbio, (char **)&data);
408 if (!PACKET_buf_init(&pkt, data, len))
411 /* Check record header type */
412 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_CHANGE_CIPHER_SPEC)
415 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
417 /* Skip the rest of the record header */
418 if (!PACKET_forward(&pkt, DTLS1_RT_HEADER_LENGTH - 3))
421 /* Check ChangeCipherSpec message */
422 if (!PACKET_get_1(&pkt, &u) || u != SSL3_MT_CCS)
424 /* A DTLS1_BAD_VER ChangeCipherSpec also contains the
425 * handshake sequence number (which is 2 here) */
426 if (!PACKET_get_net_2(&pkt, &u) || u != 0x0002)
429 /* Now check the Finished packet */
430 if (!PACKET_get_1(&pkt, &u) || u != SSL3_RT_HANDSHAKE)
432 if (!PACKET_get_net_2(&pkt, &u) || u != DTLS1_BAD_VER)
435 /* Check epoch is now 1 */
436 if (!PACKET_get_net_2(&pkt, &u) || u != 0x0001)
439 /* That'll do for now. If OpenSSL accepted *our* Finished packet
440 * then it's evidently remembered that DTLS1_BAD_VER doesn't
441 * include the handshake header in the MAC. There's not a lot of
442 * point in implementing decryption here, just to check that it
443 * continues to get it right for one more packet. */
448 #define NODROP(x) { x##UL, 0 }
449 #define DROP(x) { x##UL, 1 }
455 NODROP(1), NODROP(3), NODROP(2),
456 NODROP(0x1234), NODROP(0x1230), NODROP(0x1235),
457 NODROP(0xffff), NODROP(0x10001), NODROP(0xfffe), NODROP(0x10000),
458 DROP(0x10001), DROP(0xff), NODROP(0x100000), NODROP(0x800000), NODROP(0x7fffe1),
459 NODROP(0xffffff), NODROP(0x1000000), NODROP(0xfffffe), DROP(0xffffff), NODROP(0x1000010),
460 NODROP(0xfffffd), NODROP(0x1000011), DROP(0x12), NODROP(0x1000012),
461 NODROP(0x1ffffff), NODROP(0x2000000), DROP(0x1ff00fe), NODROP(0x2000001),
462 NODROP(0x20fffff), NODROP(0x2105500), DROP(0x20ffffe), NODROP(0x21054ff),
463 NODROP(0x211ffff), DROP(0x2110000), NODROP(0x2120000)
464 /* The last test should be NODROP, because a DROP wouldn't get tested. */
467 static int test_bad_dtls(void)
469 SSL_SESSION *sess = NULL;
479 RAND_bytes(session_id, sizeof(session_id));
480 RAND_bytes(master_secret, sizeof(master_secret));
481 RAND_bytes(cookie, sizeof(cookie));
482 RAND_bytes(server_random + 4, sizeof(server_random) - 4);
485 memcpy(server_random, &now, sizeof(now));
487 sess = client_session();
491 handshake_md = EVP_MD_CTX_new();
492 if (!TEST_ptr(handshake_md)
493 || !TEST_true(EVP_DigestInit_ex(handshake_md, EVP_md5_sha1(),
497 ctx = SSL_CTX_new(DTLS_client_method());
499 || !TEST_true(SSL_CTX_set_min_proto_version(ctx, DTLS1_BAD_VER))
500 || !TEST_true(SSL_CTX_set_max_proto_version(ctx, DTLS1_BAD_VER))
501 || !TEST_true(SSL_CTX_set_options(ctx,
502 SSL_OP_LEGACY_SERVER_CONNECT))
503 || !TEST_true(SSL_CTX_set_cipher_list(ctx, "AES128-SHA")))
506 SSL_CTX_set_security_level(ctx, 0);
509 || !TEST_true(SSL_set_session(con, sess)))
511 SSL_SESSION_free(sess);
513 rbio = BIO_new(BIO_s_mem());
514 wbio = BIO_new(BIO_s_mem());
520 SSL_set_bio(con, rbio, wbio);
522 if (!TEST_true(BIO_up_ref(rbio))) {
524 * We can't up-ref but we assigned ownership to con, so we shouldn't
525 * free in the "end" block
531 if (!TEST_true(BIO_up_ref(wbio))) {
536 SSL_set_connect_state(con);
538 /* Send initial ClientHello */
539 ret = SSL_do_handshake(con);
540 if (!TEST_int_le(ret, 0)
541 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
542 || !TEST_int_eq(validate_client_hello(wbio), 1)
543 || !TEST_true(send_hello_verify(rbio)))
546 ret = SSL_do_handshake(con);
547 if (!TEST_int_le(ret, 0)
548 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
549 || !TEST_int_eq(validate_client_hello(wbio), 2)
550 || !TEST_true(send_server_hello(rbio)))
553 ret = SSL_do_handshake(con);
554 if (!TEST_int_le(ret, 0)
555 || !TEST_int_eq(SSL_get_error(con, ret), SSL_ERROR_WANT_READ)
556 || !TEST_true(send_finished(con, rbio)))
559 ret = SSL_do_handshake(con);
560 if (!TEST_int_gt(ret, 0)
561 || !TEST_true(validate_ccs(wbio)))
564 /* While we're here and crafting packets by hand, we might as well do a
565 bit of a stress test on the DTLS record replay handling. Not Cisco-DTLS
566 specific but useful anyway for the general case. It's been broken
567 before, and in fact was broken even for a basic 0, 2, 1 test case
568 when this test was first added.... */
569 for (i = 0; i < (int)OSSL_NELEM(tests); i++) {
570 uint64_t recv_buf[2];
572 if (!TEST_true(send_record(rbio, SSL3_RT_APPLICATION_DATA, tests[i].seq,
573 &tests[i].seq, sizeof(uint64_t)))) {
574 TEST_error("Failed to send data seq #0x%x%08x (%d)\n",
575 (unsigned int)(tests[i].seq >> 32), (unsigned int)tests[i].seq, i);
582 ret = SSL_read(con, recv_buf, 2 * sizeof(uint64_t));
583 if (!TEST_int_eq(ret, (int)sizeof(uint64_t))) {
584 TEST_error("SSL_read failed or wrong size on seq#0x%x%08x (%d)\n",
585 (unsigned int)(tests[i].seq >> 32), (unsigned int)tests[i].seq, i);
588 if (!TEST_true(recv_buf[0] == tests[i].seq))
592 /* The last test cannot be DROP() */
593 if (!TEST_false(tests[i-1].drop))
603 EVP_MD_CTX_free(handshake_md);
608 int setup_tests(void)
610 ADD_TEST(test_bad_dtls);