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
59 memset(buf, 0x5a, sizeof(buf));
60
61 if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl,
62 NULL, NULL)))
63 goto end;
64
65 if (no_etm)
66 SSL_set_options(srvr_ssl, SSL_OP_NO_ENCRYPT_THEN_MAC);
67
68 if (!TEST_true(SSL_set_cipher_list(srvr_ssl, cs))
69 || !TEST_true(SSL_set_cipher_list(clnt_ssl, cs))
70 || !TEST_ptr(sc_bio = SSL_get_rbio(srvr_ssl))
71 || !TEST_true(create_ssl_connection(clnt_ssl, srvr_ssl,
72 SSL_ERROR_NONE)))
73 goto end;
74
75 if (debug)
76 TEST_info("Channel established");
77
78 /* For record MTU values between 500 and 539, call DTLS_get_data_mtu()
79 * to query the payload MTU which will fit. */
80 for (i = 0; i < 30; i++) {
81 SSL_set_mtu(clnt_ssl, 500 + i);
82 mtus[i] = DTLS_get_data_mtu(clnt_ssl);
83 if (debug)
84 TEST_info("%s%s MTU for record mtu %d = %lu",
85 cs, no_etm ? "-noEtM" : "",
86 500 + i, (unsigned long)mtus[i]);
87 if (!TEST_size_t_ne(mtus[i], 0)) {
88 TEST_info("Cipher %s MTU %d", cs, 500 + i);
89 goto end;
90 }
91 }
92
93 /* Now get out of the way */
94 SSL_set_mtu(clnt_ssl, 1000);
95
96 /*
97 * Now for all values in the range of payload MTUs, send a payload of
98 * that size and see what actual record size we end up with.
99 */
100 for (s = mtus[0]; s <= mtus[29]; s++) {
101 size_t reclen;
102
103 if (!TEST_int_eq(SSL_write(clnt_ssl, buf, s), (int)s))
104 goto end;
105 reclen = BIO_read(sc_bio, buf, sizeof(buf));
106 if (debug)
107 TEST_info("record %zu for payload %zu", reclen, s);
108
109 for (i = 0; i < 30; i++) {
110 /* DTLS_get_data_mtu() with record MTU 500+i returned mtus[i] ... */
111
112 if (!TEST_false(s <= mtus[i] && reclen > (size_t)(500 + i))) {
113 /*
114 * We sent a packet smaller than or equal to mtus[j] and
115 * that made a record *larger* than the record MTU 500+j!
116 */
117 TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",
118 cs, (unsigned long)s, (unsigned long)mtus[i],
119 (unsigned long)reclen, 500 + i);
120 goto end;
121 }
122 if (!TEST_false(s > mtus[i] && reclen <= (size_t)(500 + i))) {
123 /*
124 * We sent a *larger* packet than mtus[i] and that *still*
125 * fits within the record MTU 500+i, so DTLS_get_data_mtu()
126 * was overly pessimistic.
127 */
128 TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",
129 cs, (unsigned long)s, (unsigned long)mtus[i],
130 (unsigned long)reclen, 500 + i);
131 goto end;
132 }
133 }
134 }
135 rv = 1;
136 if (SSL_READ_ETM(clnt_ssl))
137 rv = 2;
138 end:
139 SSL_free(clnt_ssl);
140 SSL_free(srvr_ssl);
141 return rv;
142 }
143
run_mtu_tests(void)144 static int run_mtu_tests(void)
145 {
146 SSL_CTX *ctx = NULL;
147 STACK_OF(SSL_CIPHER) *ciphers;
148 int i, ret = 0;
149
150 if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method())))
151 goto end;
152
153 SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
154 SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);
155 SSL_CTX_set_security_level(ctx, 0);
156
157 /*
158 * We only care about iterating over each enc/mac; we don't want to
159 * repeat the test for each auth/kx variant. So keep life simple and
160 * only do (non-DH) PSK.
161 */
162 if (!TEST_true(SSL_CTX_set_cipher_list(ctx, "PSK")))
163 goto end;
164
165 ciphers = SSL_CTX_get_ciphers(ctx);
166 for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
167 const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);
168 const char *cipher_name = SSL_CIPHER_get_name(cipher);
169
170 /* As noted above, only one test for each enc/mac variant. */
171 if (strncmp(cipher_name, "PSK-", 4) != 0)
172 continue;
173
174 if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 0), 0))
175 break;
176 TEST_info("%s OK", cipher_name);
177 if (ret == 1)
178 continue;
179
180 /* mtu_test() returns 2 if it used Encrypt-then-MAC */
181 if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 1), 0))
182 break;
183 TEST_info("%s without EtM OK", cipher_name);
184 }
185
186 end:
187 SSL_CTX_free(ctx);
188 return ret;
189 }
190
test_server_mtu_larger_than_max_fragment_length(void)191 static int test_server_mtu_larger_than_max_fragment_length(void)
192 {
193 SSL_CTX *ctx = NULL;
194 SSL *srvr_ssl = NULL, *clnt_ssl = NULL;
195 int rv = 0;
196
197 if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method())))
198 goto end;
199
200 SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
201 SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);
202
203 #ifndef OPENSSL_NO_DH
204 if (!TEST_true(SSL_CTX_set_dh_auto(ctx, 1)))
205 goto end;
206 #endif
207
208 if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl,
209 NULL, NULL)))
210 goto end;
211
212 SSL_set_options(srvr_ssl, SSL_OP_NO_QUERY_MTU);
213 if (!TEST_true(DTLS_set_link_mtu(srvr_ssl, 1500)))
214 goto end;
215
216 SSL_set_tlsext_max_fragment_length(clnt_ssl,
217 TLSEXT_max_fragment_length_512);
218
219 if (!TEST_true(create_ssl_connection(srvr_ssl, clnt_ssl,
220 SSL_ERROR_NONE)))
221 goto end;
222
223 rv = 1;
224
225 end:
226 SSL_free(clnt_ssl);
227 SSL_free(srvr_ssl);
228 SSL_CTX_free(ctx);
229 return rv;
230 }
231
setup_tests(void)232 int setup_tests(void)
233 {
234 ADD_TEST(run_mtu_tests);
235 ADD_TEST(test_server_mtu_larger_than_max_fragment_length);
236 return 1;
237 }
238
cleanup_tests(void)239 void cleanup_tests(void)
240 {
241 bio_s_mempacket_test_free();
242 }
243