1 /* 2 * Copyright (c) 2008 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthias Schmidt <matthias@dragonflybsd.org>, University of Marburg, 6 * Germany. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the 17 * distribution. 18 * 3. Neither the name of The DragonFly Project nor the names of its 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific, prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 31 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <openssl/x509.h> 37 #include <openssl/md5.h> 38 #include <openssl/ssl.h> 39 #include <openssl/err.h> 40 #include <openssl/pem.h> 41 #include <openssl/rand.h> 42 43 #include <string.h> 44 #include <syslog.h> 45 46 #include "dma.h" 47 48 static int 49 init_cert_file(SSL_CTX *ctx, const char *path) 50 { 51 int error; 52 53 /* Load certificate into ctx */ 54 error = SSL_CTX_use_certificate_chain_file(ctx, path); 55 if (error < 1) { 56 syslog(LOG_ERR, "SSL: Cannot load certificate `%s': %s", path, ssl_errstr()); 57 return (-1); 58 } 59 60 /* Add private key to ctx */ 61 error = SSL_CTX_use_PrivateKey_file(ctx, path, SSL_FILETYPE_PEM); 62 if (error < 1) { 63 syslog(LOG_ERR, "SSL: Cannot load private key `%s': %s", path, ssl_errstr()); 64 return (-1); 65 } 66 67 /* 68 * Check the consistency of a private key with the corresponding 69 * certificate 70 */ 71 error = SSL_CTX_check_private_key(ctx); 72 if (error < 1) { 73 syslog(LOG_ERR, "SSL: Cannot check private key: %s", ssl_errstr()); 74 return (-1); 75 } 76 77 return (0); 78 } 79 80 int 81 smtp_init_crypto(int fd, int feature) 82 { 83 SSL_CTX *ctx = NULL; 84 #if (OPENSSL_VERSION_NUMBER >= 0x00909000L) 85 const SSL_METHOD *meth = NULL; 86 #else 87 SSL_METHOD *meth = NULL; 88 #endif 89 X509 *cert; 90 int error; 91 92 /* XXX clean up on error/close */ 93 /* Init SSL library */ 94 SSL_library_init(); 95 SSL_load_error_strings(); 96 97 // Allow any possible version 98 #if (OPENSSL_VERSION_NUMBER >= 0x10100000L) 99 meth = TLS_client_method(); 100 #else 101 meth = SSLv23_client_method(); 102 #endif 103 104 ctx = SSL_CTX_new(meth); 105 if (ctx == NULL) { 106 syslog(LOG_WARNING, "remote delivery deferred: SSL init failed: %s", ssl_errstr()); 107 return (1); 108 } 109 110 /* User supplied a certificate */ 111 if (config.certfile != NULL) { 112 error = init_cert_file(ctx, config.certfile); 113 if (error) { 114 syslog(LOG_WARNING, "remote delivery deferred"); 115 return (1); 116 } 117 } 118 119 /* 120 * If the user wants STARTTLS, we have to send EHLO here 121 */ 122 if (((feature & SECURETRANS) != 0) && 123 (feature & STARTTLS) != 0) { 124 /* TLS init phase, disable SSL_write */ 125 config.features |= NOSSL; 126 127 send_remote_command(fd, "EHLO %s", hostname()); 128 if (read_remote(fd, 0, NULL) == 2) { 129 send_remote_command(fd, "STARTTLS"); 130 if (read_remote(fd, 0, NULL) != 2) { 131 if ((feature & TLS_OPP) == 0) { 132 syslog(LOG_ERR, "remote delivery deferred: STARTTLS not available: %s", neterr); 133 return (1); 134 } else { 135 syslog(LOG_INFO, "in opportunistic TLS mode, STARTTLS not available: %s", neterr); 136 return (0); 137 } 138 } 139 } 140 /* End of TLS init phase, enable SSL_write/read */ 141 config.features &= ~NOSSL; 142 } 143 144 config.ssl = SSL_new(ctx); 145 if (config.ssl == NULL) { 146 syslog(LOG_NOTICE, "remote delivery deferred: SSL struct creation failed: %s", 147 ssl_errstr()); 148 return (1); 149 } 150 151 /* Set ssl to work in client mode */ 152 SSL_set_connect_state(config.ssl); 153 154 /* Set fd for SSL in/output */ 155 error = SSL_set_fd(config.ssl, fd); 156 if (error == 0) { 157 syslog(LOG_NOTICE, "remote delivery deferred: SSL set fd failed: %s", 158 ssl_errstr()); 159 return (1); 160 } 161 162 /* Open SSL connection */ 163 error = SSL_connect(config.ssl); 164 if (error < 0) { 165 syslog(LOG_ERR, "remote delivery deferred: SSL handshake failed fatally: %s", 166 ssl_errstr()); 167 return (1); 168 } 169 170 /* Get peer certificate */ 171 cert = SSL_get_peer_certificate(config.ssl); 172 if (cert == NULL) { 173 syslog(LOG_WARNING, "remote delivery deferred: Peer did not provide certificate: %s", 174 ssl_errstr()); 175 } 176 X509_free(cert); 177 178 return (0); 179 } 180 181 /* 182 * hmac_md5() taken out of RFC 2104. This RFC was written by H. Krawczyk, 183 * M. Bellare and R. Canetti. 184 * 185 * text pointer to data stream 186 * text_len length of data stream 187 * key pointer to authentication key 188 * key_len length of authentication key 189 * digest caller digest to be filled int 190 */ 191 void 192 hmac_md5(unsigned char *text, int text_len, unsigned char *key, int key_len, 193 unsigned char* digest) 194 { 195 MD5_CTX context; 196 unsigned char k_ipad[65]; /* inner padding - 197 * key XORd with ipad 198 */ 199 unsigned char k_opad[65]; /* outer padding - 200 * key XORd with opad 201 */ 202 unsigned char tk[16]; 203 int i; 204 /* if key is longer than 64 bytes reset it to key=MD5(key) */ 205 if (key_len > 64) { 206 207 MD5_CTX tctx; 208 209 MD5_Init(&tctx); 210 MD5_Update(&tctx, key, key_len); 211 MD5_Final(tk, &tctx); 212 213 key = tk; 214 key_len = 16; 215 } 216 217 /* 218 * the HMAC_MD5 transform looks like: 219 * 220 * MD5(K XOR opad, MD5(K XOR ipad, text)) 221 * 222 * where K is an n byte key 223 * ipad is the byte 0x36 repeated 64 times 224 * 225 * opad is the byte 0x5c repeated 64 times 226 * and text is the data being protected 227 */ 228 229 /* start out by storing key in pads */ 230 bzero( k_ipad, sizeof k_ipad); 231 bzero( k_opad, sizeof k_opad); 232 bcopy( key, k_ipad, key_len); 233 bcopy( key, k_opad, key_len); 234 235 /* XOR key with ipad and opad values */ 236 for (i=0; i<64; i++) { 237 k_ipad[i] ^= 0x36; 238 k_opad[i] ^= 0x5c; 239 } 240 /* 241 * perform inner MD5 242 */ 243 MD5_Init(&context); /* init context for 1st 244 * pass */ 245 MD5_Update(&context, k_ipad, 64); /* start with inner pad */ 246 MD5_Update(&context, text, text_len); /* then text of datagram */ 247 MD5_Final(digest, &context); /* finish up 1st pass */ 248 /* 249 * perform outer MD5 250 */ 251 MD5_Init(&context); /* init context for 2nd 252 * pass */ 253 MD5_Update(&context, k_opad, 64); /* start with outer pad */ 254 MD5_Update(&context, digest, 16); /* then results of 1st 255 * hash */ 256 MD5_Final(digest, &context); /* finish up 2nd pass */ 257 } 258 259 /* 260 * CRAM-MD5 authentication 261 */ 262 int 263 smtp_auth_md5(int fd, char *login, char *password) 264 { 265 unsigned char digest[BUF_SIZE]; 266 char buffer[BUF_SIZE], ascii_digest[33]; 267 char *temp; 268 int len, i; 269 static char hextab[] = "0123456789abcdef"; 270 271 temp = calloc(BUF_SIZE, 1); 272 memset(buffer, 0, sizeof(buffer)); 273 memset(digest, 0, sizeof(digest)); 274 memset(ascii_digest, 0, sizeof(ascii_digest)); 275 276 /* Send AUTH command according to RFC 2554 */ 277 send_remote_command(fd, "AUTH CRAM-MD5"); 278 if (read_remote(fd, sizeof(buffer), buffer) != 3) { 279 syslog(LOG_DEBUG, "smarthost authentication:" 280 " AUTH cram-md5 not available: %s", neterr); 281 /* if cram-md5 is not available */ 282 free(temp); 283 return (-1); 284 } 285 286 /* skip 3 char status + 1 char space */ 287 base64_decode(buffer + 4, temp); 288 hmac_md5((unsigned char *)temp, strlen(temp), 289 (unsigned char *)password, strlen(password), digest); 290 free(temp); 291 292 ascii_digest[32] = 0; 293 for (i = 0; i < 16; i++) { 294 ascii_digest[2*i] = hextab[digest[i] >> 4]; 295 ascii_digest[2*i+1] = hextab[digest[i] & 15]; 296 } 297 298 /* prepare answer */ 299 snprintf(buffer, BUF_SIZE, "%s %s", login, ascii_digest); 300 301 /* encode answer */ 302 len = base64_encode(buffer, strlen(buffer), &temp); 303 if (len < 0) { 304 syslog(LOG_ERR, "can not encode auth reply: %m"); 305 return (-1); 306 } 307 308 /* send answer */ 309 send_remote_command(fd, "%s", temp); 310 free(temp); 311 if (read_remote(fd, 0, NULL) != 2) { 312 syslog(LOG_WARNING, "remote delivery deferred:" 313 " AUTH cram-md5 failed: %s", neterr); 314 return (-2); 315 } 316 317 return (0); 318 } 319