1 /*
2 * Copyright 2016-2022 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9
10 #include <stdio.h>
11 #include <string.h>
12
13 #include <openssl/dtls1.h>
14 #include <openssl/ssl.h>
15 #include <openssl/err.h>
16
17 #include "helpers/ssltestlib.h"
18 #include "testutil.h"
19
20 /* for SSL_READ_ETM() */
21 #include "../ssl/ssl_local.h"
22
23 static int debug = 0;
24
clnt_psk_callback(SSL * ssl,const char * hint,char * ident,unsigned int max_ident_len,unsigned char * psk,unsigned int max_psk_len)25 static unsigned int clnt_psk_callback(SSL *ssl, const char *hint,
26 char *ident, unsigned int max_ident_len,
27 unsigned char *psk,
28 unsigned int max_psk_len)
29 {
30 BIO_snprintf(ident, max_ident_len, "psk");
31
32 if (max_psk_len > 20)
33 max_psk_len = 20;
34 memset(psk, 0x5a, max_psk_len);
35
36 return max_psk_len;
37 }
38
srvr_psk_callback(SSL * ssl,const char * identity,unsigned char * psk,unsigned int max_psk_len)39 static unsigned int srvr_psk_callback(SSL *ssl, const char *identity,
40 unsigned char *psk,
41 unsigned int max_psk_len)
42 {
43 if (max_psk_len > 20)
44 max_psk_len = 20;
45 memset(psk, 0x5a, max_psk_len);
46 return max_psk_len;
47 }
48
mtu_test(SSL_CTX * ctx,const char * cs,int no_etm)49 static int mtu_test(SSL_CTX *ctx, const char *cs, int no_etm)
50 {
51 SSL *srvr_ssl = NULL, *clnt_ssl = NULL;
52 BIO *sc_bio = NULL;
53 int i;
54 size_t s;
55 size_t mtus[30];
56 unsigned char buf[600];
57 int rv = 0;
58 SSL_CONNECTION *clnt_sc;
59
60 memset(buf, 0x5a, sizeof(buf));
61
62 if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl,
63 NULL, NULL)))
64 goto end;
65
66 if (no_etm)
67 SSL_set_options(srvr_ssl, SSL_OP_NO_ENCRYPT_THEN_MAC);
68
69 if (!TEST_true(SSL_set_cipher_list(srvr_ssl, cs))
70 || !TEST_true(SSL_set_cipher_list(clnt_ssl, cs))
71 || !TEST_ptr(sc_bio = SSL_get_rbio(srvr_ssl))
72 || !TEST_true(create_ssl_connection(clnt_ssl, srvr_ssl,
73 SSL_ERROR_NONE)))
74 goto end;
75
76 if (debug)
77 TEST_info("Channel established");
78
79 /* For record MTU values between 500 and 539, call DTLS_get_data_mtu()
80 * to query the payload MTU which will fit. */
81 for (i = 0; i < 30; i++) {
82 SSL_set_mtu(clnt_ssl, 500 + i);
83 mtus[i] = DTLS_get_data_mtu(clnt_ssl);
84 if (debug)
85 TEST_info("%s%s MTU for record mtu %d = %lu",
86 cs, no_etm ? "-noEtM" : "",
87 500 + i, (unsigned long)mtus[i]);
88 if (!TEST_size_t_ne(mtus[i], 0)) {
89 TEST_info("Cipher %s MTU %d", cs, 500 + i);
90 goto end;
91 }
92 }
93
94 /* Now get out of the way */
95 SSL_set_mtu(clnt_ssl, 1000);
96
97 /*
98 * Now for all values in the range of payload MTUs, send a payload of
99 * that size and see what actual record size we end up with.
100 */
101 for (s = mtus[0]; s <= mtus[29]; s++) {
102 size_t reclen;
103
104 if (!TEST_int_eq(SSL_write(clnt_ssl, buf, s), (int)s))
105 goto end;
106 reclen = BIO_read(sc_bio, buf, sizeof(buf));
107 if (debug)
108 TEST_info("record %zu for payload %zu", reclen, s);
109
110 for (i = 0; i < 30; i++) {
111 /* DTLS_get_data_mtu() with record MTU 500+i returned mtus[i] ... */
112
113 if (!TEST_false(s <= mtus[i] && reclen > (size_t)(500 + i))) {
114 /*
115 * We sent a packet smaller than or equal to mtus[j] and
116 * that made a record *larger* than the record MTU 500+j!
117 */
118 TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",
119 cs, (unsigned long)s, (unsigned long)mtus[i],
120 (unsigned long)reclen, 500 + i);
121 goto end;
122 }
123 if (!TEST_false(s > mtus[i] && reclen <= (size_t)(500 + i))) {
124 /*
125 * We sent a *larger* packet than mtus[i] and that *still*
126 * fits within the record MTU 500+i, so DTLS_get_data_mtu()
127 * was overly pessimistic.
128 */
129 TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",
130 cs, (unsigned long)s, (unsigned long)mtus[i],
131 (unsigned long)reclen, 500 + i);
132 goto end;
133 }
134 }
135 }
136 if (!TEST_ptr(clnt_sc = SSL_CONNECTION_FROM_SSL_ONLY(clnt_ssl)))
137 goto end;
138 rv = 1;
139 if (SSL_READ_ETM(clnt_sc))
140 rv = 2;
141 end:
142 SSL_free(clnt_ssl);
143 SSL_free(srvr_ssl);
144 return rv;
145 }
146
run_mtu_tests(void)147 static int run_mtu_tests(void)
148 {
149 SSL_CTX *ctx = NULL;
150 STACK_OF(SSL_CIPHER) *ciphers;
151 int i, ret = 0;
152
153 if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method())))
154 goto end;
155
156 SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
157 SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);
158 SSL_CTX_set_security_level(ctx, 0);
159
160 /*
161 * We only care about iterating over each enc/mac; we don't want to
162 * repeat the test for each auth/kx variant. So keep life simple and
163 * only do (non-DH) PSK.
164 */
165 if (!TEST_true(SSL_CTX_set_cipher_list(ctx, "PSK")))
166 goto end;
167
168 ciphers = SSL_CTX_get_ciphers(ctx);
169 for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
170 const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);
171 const char *cipher_name = SSL_CIPHER_get_name(cipher);
172
173 /* As noted above, only one test for each enc/mac variant. */
174 if (!HAS_PREFIX(cipher_name, "PSK-"))
175 continue;
176
177 if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 0), 0))
178 break;
179 TEST_info("%s OK", cipher_name);
180 if (ret == 1)
181 continue;
182
183 /* mtu_test() returns 2 if it used Encrypt-then-MAC */
184 if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 1), 0))
185 break;
186 TEST_info("%s without EtM OK", cipher_name);
187 }
188
189 end:
190 SSL_CTX_free(ctx);
191 return ret;
192 }
193
test_server_mtu_larger_than_max_fragment_length(void)194 static int test_server_mtu_larger_than_max_fragment_length(void)
195 {
196 SSL_CTX *ctx = NULL;
197 SSL *srvr_ssl = NULL, *clnt_ssl = NULL;
198 int rv = 0;
199
200 if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method())))
201 goto end;
202
203 SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
204 SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);
205
206 #ifndef OPENSSL_NO_DH
207 if (!TEST_true(SSL_CTX_set_dh_auto(ctx, 1)))
208 goto end;
209 #endif
210
211 if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl,
212 NULL, NULL)))
213 goto end;
214
215 SSL_set_options(srvr_ssl, SSL_OP_NO_QUERY_MTU);
216 if (!TEST_true(DTLS_set_link_mtu(srvr_ssl, 1500)))
217 goto end;
218
219 SSL_set_tlsext_max_fragment_length(clnt_ssl,
220 TLSEXT_max_fragment_length_512);
221
222 if (!TEST_true(create_ssl_connection(srvr_ssl, clnt_ssl,
223 SSL_ERROR_NONE)))
224 goto end;
225
226 rv = 1;
227
228 end:
229 SSL_free(clnt_ssl);
230 SSL_free(srvr_ssl);
231 SSL_CTX_free(ctx);
232 return rv;
233 }
234
setup_tests(void)235 int setup_tests(void)
236 {
237 ADD_TEST(run_mtu_tests);
238 ADD_TEST(test_server_mtu_larger_than_max_fragment_length);
239 return 1;
240 }
241
cleanup_tests(void)242 void cleanup_tests(void)
243 {
244 bio_s_mempacket_test_free();
245 }
246
