test/dtls_mtu_test.c

   1 /*
   2  * Copyright 2016-2018 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_locl.h"
  22
  23 static int debug = 0;
  24
  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
  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
  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
 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     bio_s_mempacket_test_free();
 189     return ret;
 190 }
 191
 192 int setup_tests(void)
 193 {
 194     ADD_TEST(run_mtu_tests);
 195     return 1;
 196 }