test/dtls_mtu_test.c

   1 /*
   2  * Copyright 2016-2020 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 "ssltestlib.h"
  18 #include "testutil.h"
  19
  20 /* for SSL_READ_ETM() */
  21 #include "../ssl/ssl_local.h"
  22
  23 DEFINE_STACK_OF(SSL_CIPHER)
  24
  25 static int debug = 0;
  26
  27 static unsigned int clnt_psk_callback(SSL *ssl, const char *hint,
  28                                       char *ident, unsigned int max_ident_len,
  29                                       unsigned char *psk,
  30                                       unsigned int max_psk_len)
  31 {
  32     BIO_snprintf(ident, max_ident_len, "psk");
  33
  34     if (max_psk_len > 20)
  35         max_psk_len = 20;
  36     memset(psk, 0x5a, max_psk_len);
  37
  38     return max_psk_len;
  39 }
  40
  41 static unsigned int srvr_psk_callback(SSL *ssl, const char *identity,
  42                                       unsigned char *psk,
  43                                       unsigned int max_psk_len)
  44 {
  45     if (max_psk_len > 20)
  46         max_psk_len = 20;
  47     memset(psk, 0x5a, max_psk_len);
  48     return max_psk_len;
  49 }
  50
  51 static int mtu_test(SSL_CTX *ctx, const char *cs, int no_etm)
  52 {
  53     SSL *srvr_ssl = NULL, *clnt_ssl = NULL;
  54     BIO *sc_bio = NULL;
  55     int i;
  56     size_t s;
  57     size_t mtus[30];
  58     unsigned char buf[600];
  59     int rv = 0;
  60
  61     memset(buf, 0x5a, sizeof(buf));
  62
  63     if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl,
  64                                       NULL, NULL)))
  65         goto end;
  66
  67     if (no_etm)
  68         SSL_set_options(srvr_ssl, SSL_OP_NO_ENCRYPT_THEN_MAC);
  69
  70     if (!TEST_true(SSL_set_cipher_list(srvr_ssl, cs))
  71             || !TEST_true(SSL_set_cipher_list(clnt_ssl, cs))
  72             || !TEST_ptr(sc_bio = SSL_get_rbio(srvr_ssl))
  73             || !TEST_true(create_ssl_connection(clnt_ssl, srvr_ssl,
  74                                                 SSL_ERROR_NONE)))
  75         goto end;
  76
  77     if (debug)
  78         TEST_info("Channel established");
  79
  80     /* For record MTU values between 500 and 539, call DTLS_get_data_mtu()
  81      * to query the payload MTU which will fit. */
  82     for (i = 0; i < 30; i++) {
  83         SSL_set_mtu(clnt_ssl, 500 + i);
  84         mtus[i] = DTLS_get_data_mtu(clnt_ssl);
  85         if (debug)
  86             TEST_info("%s%s MTU for record mtu %d = %lu",
  87                       cs, no_etm ? "-noEtM" : "",
  88                       500 + i, (unsigned long)mtus[i]);
  89         if (!TEST_size_t_ne(mtus[i], 0)) {
  90             TEST_info("Cipher %s MTU %d", cs, 500 + i);
  91             goto end;
  92         }
  93     }
  94
  95     /* Now get out of the way */
  96     SSL_set_mtu(clnt_ssl, 1000);
  97
  98     /*
  99      * Now for all values in the range of payload MTUs, send a payload of
 100      * that size and see what actual record size we end up with.
 101      */
 102     for (s = mtus[0]; s <= mtus[29]; s++) {
 103         size_t reclen;
 104
 105         if (!TEST_int_eq(SSL_write(clnt_ssl, buf, s), (int)s))
 106             goto end;
 107         reclen = BIO_read(sc_bio, buf, sizeof(buf));
 108         if (debug)
 109             TEST_info("record %zu for payload %zu", reclen, s);
 110
 111         for (i = 0; i < 30; i++) {
 112             /* DTLS_get_data_mtu() with record MTU 500+i returned mtus[i] ... */
 113
 114             if (!TEST_false(s <= mtus[i] && reclen > (size_t)(500 + i))) {
 115                 /*
 116                  * We sent a packet smaller than or equal to mtus[j] and
 117                  * that made a record *larger* than the record MTU 500+j!
 118                  */
 119                 TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",
 120                            cs, (unsigned long)s, (unsigned long)mtus[i],
 121                            (unsigned long)reclen, 500 + i);
 122                 goto end;
 123             }
 124             if (!TEST_false(s > mtus[i] && reclen <= (size_t)(500 + i))) {
 125                 /*
 126                  * We sent a *larger* packet than mtus[i] and that *still*
 127                  * fits within the record MTU 500+i, so DTLS_get_data_mtu()
 128                  * was overly pessimistic.
 129                  */
 130                 TEST_error("%s: s=%lu, mtus[i]=%lu, reclen=%lu, i=%d",
 131                            cs, (unsigned long)s, (unsigned long)mtus[i],
 132                            (unsigned long)reclen, 500 + i);
 133                 goto end;
 134             }
 135         }
 136     }
 137     rv = 1;
 138     if (SSL_READ_ETM(clnt_ssl))
 139         rv = 2;
 140  end:
 141     SSL_free(clnt_ssl);
 142     SSL_free(srvr_ssl);
 143     return rv;
 144 }
 145
 146 static int run_mtu_tests(void)
 147 {
 148     SSL_CTX *ctx = NULL;
 149     STACK_OF(SSL_CIPHER) *ciphers;
 150     int i, ret = 0;
 151
 152     if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method())))
 153         goto end;
 154
 155     SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback);
 156     SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback);
 157     SSL_CTX_set_security_level(ctx, 0);
 158
 159     /*
 160      * We only care about iterating over each enc/mac; we don't want to
 161      * repeat the test for each auth/kx variant. So keep life simple and
 162      * only do (non-DH) PSK.
 163      */
 164     if (!TEST_true(SSL_CTX_set_cipher_list(ctx, "PSK")))
 165         goto end;
 166
 167     ciphers = SSL_CTX_get_ciphers(ctx);
 168     for (i = 0; i < sk_SSL_CIPHER_num(ciphers); i++) {
 169         const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(ciphers, i);
 170         const char *cipher_name = SSL_CIPHER_get_name(cipher);
 171
 172         /* As noted above, only one test for each enc/mac variant. */
 173         if (strncmp(cipher_name, "PSK-", 4) != 0)
 174             continue;
 175
 176         if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 0), 0))
 177             break;
 178         TEST_info("%s OK", cipher_name);
 179         if (ret == 1)
 180             continue;
 181
 182         /* mtu_test() returns 2 if it used Encrypt-then-MAC */
 183         if (!TEST_int_gt(ret = mtu_test(ctx, cipher_name, 1), 0))
 184             break;
 185         TEST_info("%s without EtM OK", cipher_name);
 186     }
 187
 188  end:
 189     SSL_CTX_free(ctx);
 190     bio_s_mempacket_test_free();
 191     return ret;
 192 }
 193
 194 int setup_tests(void)
 195 {
 196     ADD_TEST(run_mtu_tests);
 197     return 1;
 198 }