1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] 56 */ 57 /* ==================================================================== 58 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. 59 * 60 * Redistribution and use in source and binary forms, with or without 61 * modification, are permitted provided that the following conditions 62 * are met: 63 * 64 * 1. Redistributions of source code must retain the above copyright 65 * notice, this list of conditions and the following disclaimer. 66 * 67 * 2. Redistributions in binary form must reproduce the above copyright 68 * notice, this list of conditions and the following disclaimer in 69 * the documentation and/or other materials provided with the 70 * distribution. 71 * 72 * 3. All advertising materials mentioning features or use of this 73 * software must display the following acknowledgment: 74 * "This product includes software developed by the OpenSSL Project 75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 76 * 77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 78 * endorse or promote products derived from this software without 79 * prior written permission. For written permission, please contact 80 * openssl-core (at) openssl.org. 81 * 82 * 5. Products derived from this software may not be called "OpenSSL" 83 * nor may "OpenSSL" appear in their names without prior written 84 * permission of the OpenSSL Project. 85 * 86 * 6. Redistributions of any form whatsoever must retain the following 87 * acknowledgment: 88 * "This product includes software developed by the OpenSSL Project 89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 90 * 91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 102 * OF THE POSSIBILITY OF SUCH DAMAGE. 103 * ==================================================================== 104 * 105 * This product includes cryptographic software written by Eric Young 106 * (eay (at) cryptsoft.com). This product includes software written by Tim 107 * Hudson (tjh (at) cryptsoft.com). */ 108 109 #include <openssl/ssl.h> 110 111 #include <assert.h> 112 113 #include <openssl/bytestring.h> 114 #include <openssl/err.h> 115 116 #include "internal.h" 117 118 119 /* kMaxEmptyRecords is the number of consecutive, empty records that will be 120 * processed. Without this limit an attacker could send empty records at a 121 * faster rate than we can process and cause record processing to loop 122 * forever. */ 123 static const uint8_t kMaxEmptyRecords = 32; 124 125 /* ssl_needs_record_splitting returns one if |ssl|'s current outgoing cipher 126 * state needs record-splitting and zero otherwise. */ 127 static int ssl_needs_record_splitting(const SSL *ssl) { 128 return !SSL_USE_EXPLICIT_IV(ssl) && ssl->aead_write_ctx != NULL && 129 (ssl->mode & SSL_MODE_CBC_RECORD_SPLITTING) != 0 && 130 SSL_CIPHER_is_block_cipher(ssl->aead_write_ctx->cipher); 131 } 132 133 size_t ssl_record_prefix_len(const SSL *ssl) { 134 if (SSL_IS_DTLS(ssl)) { 135 return DTLS1_RT_HEADER_LENGTH + 136 SSL_AEAD_CTX_explicit_nonce_len(ssl->aead_read_ctx); 137 } else { 138 return SSL3_RT_HEADER_LENGTH + 139 SSL_AEAD_CTX_explicit_nonce_len(ssl->aead_read_ctx); 140 } 141 } 142 143 size_t ssl_seal_prefix_len(const SSL *ssl) { 144 if (SSL_IS_DTLS(ssl)) { 145 return DTLS1_RT_HEADER_LENGTH + 146 SSL_AEAD_CTX_explicit_nonce_len(ssl->aead_write_ctx); 147 } else { 148 size_t ret = SSL3_RT_HEADER_LENGTH + 149 SSL_AEAD_CTX_explicit_nonce_len(ssl->aead_write_ctx); 150 if (ssl_needs_record_splitting(ssl)) { 151 ret += SSL3_RT_HEADER_LENGTH; 152 ret += ssl_cipher_get_record_split_len(ssl->aead_write_ctx->cipher); 153 } 154 return ret; 155 } 156 } 157 158 size_t ssl_max_seal_overhead(const SSL *ssl) { 159 if (SSL_IS_DTLS(ssl)) { 160 return DTLS1_RT_HEADER_LENGTH + 161 SSL_AEAD_CTX_max_overhead(ssl->aead_write_ctx); 162 } else { 163 size_t ret = SSL3_RT_HEADER_LENGTH + 164 SSL_AEAD_CTX_max_overhead(ssl->aead_write_ctx); 165 if (ssl_needs_record_splitting(ssl)) { 166 ret *= 2; 167 } 168 return ret; 169 } 170 } 171 172 enum ssl_open_record_t tls_open_record( 173 SSL *ssl, uint8_t *out_type, uint8_t *out, size_t *out_len, 174 size_t *out_consumed, uint8_t *out_alert, size_t max_out, const uint8_t *in, 175 size_t in_len) { 176 CBS cbs; 177 CBS_init(&cbs, in, in_len); 178 179 /* Decode the record header. */ 180 uint8_t type; 181 uint16_t version, ciphertext_len; 182 if (!CBS_get_u8(&cbs, &type) || 183 !CBS_get_u16(&cbs, &version) || 184 !CBS_get_u16(&cbs, &ciphertext_len)) { 185 *out_consumed = SSL3_RT_HEADER_LENGTH; 186 return ssl_open_record_partial; 187 } 188 189 /* Check the version. */ 190 if ((ssl->s3->have_version && version != ssl->version) || 191 (version >> 8) != SSL3_VERSION_MAJOR) { 192 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_NUMBER); 193 *out_alert = SSL_AD_PROTOCOL_VERSION; 194 return ssl_open_record_error; 195 } 196 197 /* Check the ciphertext length. */ 198 if (ciphertext_len > SSL3_RT_MAX_ENCRYPTED_LENGTH) { 199 OPENSSL_PUT_ERROR(SSL, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); 200 *out_alert = SSL_AD_RECORD_OVERFLOW; 201 return ssl_open_record_error; 202 } 203 204 /* Extract the body. */ 205 CBS body; 206 if (!CBS_get_bytes(&cbs, &body, ciphertext_len)) { 207 *out_consumed = SSL3_RT_HEADER_LENGTH + (size_t)ciphertext_len; 208 return ssl_open_record_partial; 209 } 210 211 if (ssl->msg_callback != NULL) { 212 ssl->msg_callback(0 /* read */, 0, SSL3_RT_HEADER, in, 213 SSL3_RT_HEADER_LENGTH, ssl, ssl->msg_callback_arg); 214 } 215 216 /* Decrypt the body. */ 217 size_t plaintext_len; 218 if (!SSL_AEAD_CTX_open(ssl->aead_read_ctx, out, &plaintext_len, max_out, 219 type, version, ssl->s3->read_sequence, CBS_data(&body), 220 CBS_len(&body))) { 221 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 222 *out_alert = SSL_AD_BAD_RECORD_MAC; 223 return ssl_open_record_error; 224 } 225 if (!ssl3_record_sequence_update(ssl->s3->read_sequence, 8)) { 226 *out_alert = SSL_AD_INTERNAL_ERROR; 227 return ssl_open_record_error; 228 } 229 230 /* Check the plaintext length. */ 231 if (plaintext_len > SSL3_RT_MAX_PLAIN_LENGTH) { 232 OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG); 233 *out_alert = SSL_AD_RECORD_OVERFLOW; 234 return ssl_open_record_error; 235 } 236 237 /* Limit the number of consecutive empty records. */ 238 if (plaintext_len == 0) { 239 ssl->s3->empty_record_count++; 240 if (ssl->s3->empty_record_count > kMaxEmptyRecords) { 241 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_EMPTY_FRAGMENTS); 242 *out_alert = SSL_AD_UNEXPECTED_MESSAGE; 243 return ssl_open_record_error; 244 } 245 /* Apart from the limit, empty records are returned up to the caller. This 246 * allows the caller to reject records of the wrong type. */ 247 } else { 248 ssl->s3->empty_record_count = 0; 249 } 250 251 *out_type = type; 252 *out_len = plaintext_len; 253 *out_consumed = in_len - CBS_len(&cbs); 254 return ssl_open_record_success; 255 } 256 257 static int do_seal_record(SSL *ssl, uint8_t *out, size_t *out_len, 258 size_t max_out, uint8_t type, const uint8_t *in, 259 size_t in_len) { 260 if (max_out < SSL3_RT_HEADER_LENGTH) { 261 OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL); 262 return 0; 263 } 264 /* Check the record header does not alias any part of the input. 265 * |SSL_AEAD_CTX_seal| will internally enforce other aliasing requirements. */ 266 if (in < out + SSL3_RT_HEADER_LENGTH && out < in + in_len) { 267 OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT); 268 return 0; 269 } 270 271 out[0] = type; 272 273 /* Some servers hang if initial ClientHello is larger than 256 bytes and 274 * record version number > TLS 1.0. */ 275 uint16_t wire_version = ssl->version; 276 if (!ssl->s3->have_version && ssl->version > SSL3_VERSION) { 277 wire_version = TLS1_VERSION; 278 } 279 out[1] = wire_version >> 8; 280 out[2] = wire_version & 0xff; 281 282 size_t ciphertext_len; 283 if (!SSL_AEAD_CTX_seal(ssl->aead_write_ctx, out + SSL3_RT_HEADER_LENGTH, 284 &ciphertext_len, max_out - SSL3_RT_HEADER_LENGTH, 285 type, wire_version, ssl->s3->write_sequence, in, 286 in_len) || 287 !ssl3_record_sequence_update(ssl->s3->write_sequence, 8)) { 288 return 0; 289 } 290 291 if (ciphertext_len >= 1 << 16) { 292 OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); 293 return 0; 294 } 295 out[3] = ciphertext_len >> 8; 296 out[4] = ciphertext_len & 0xff; 297 298 *out_len = SSL3_RT_HEADER_LENGTH + ciphertext_len; 299 300 if (ssl->msg_callback) { 301 ssl->msg_callback(1 /* write */, 0, SSL3_RT_HEADER, out, 302 SSL3_RT_HEADER_LENGTH, ssl, ssl->msg_callback_arg); 303 } 304 305 return 1; 306 } 307 308 int tls_seal_record(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out, 309 uint8_t type, const uint8_t *in, size_t in_len) { 310 size_t frag_len = 0; 311 if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 && 312 ssl_needs_record_splitting(ssl)) { 313 /* |do_seal_record| will notice if it clobbers |in[0]|, but not if it 314 * aliases the rest of |in|. */ 315 if (in + 1 <= out && out < in + in_len) { 316 OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT); 317 return 0; 318 } 319 /* Ensure |do_seal_record| does not write beyond |in[0]|. */ 320 size_t frag_max_out = max_out; 321 if (out <= in + 1 && in + 1 < out + frag_max_out) { 322 frag_max_out = (size_t)(in + 1 - out); 323 } 324 if (!do_seal_record(ssl, out, &frag_len, frag_max_out, type, in, 1)) { 325 return 0; 326 } 327 in++; 328 in_len--; 329 out += frag_len; 330 max_out -= frag_len; 331 332 assert(SSL3_RT_HEADER_LENGTH + 333 ssl_cipher_get_record_split_len(ssl->aead_write_ctx->cipher) == 334 frag_len); 335 } 336 337 if (!do_seal_record(ssl, out, out_len, max_out, type, in, in_len)) { 338 return 0; 339 } 340 *out_len += frag_len; 341 return 1; 342 } 343
