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 <syslog.h> 44 45 #include "dma.h" 46 47 static int 48 init_cert_file(SSL_CTX *ctx, const char *path) 49 { 50 int error; 51 52 /* Load certificate into ctx */ 53 error = SSL_CTX_use_certificate_chain_file(ctx, path); 54 if (error < 1) { 55 syslog(LOG_ERR, "SSL: Cannot load certificate `%s': %s", path, ssl_errstr()); 56 return (-1); 57 } 58 59 /* Add private key to ctx */ 60 error = SSL_CTX_use_PrivateKey_file(ctx, path, SSL_FILETYPE_PEM); 61 if (error < 1) { 62 syslog(LOG_ERR, "SSL: Cannot load private key `%s': %s", path, ssl_errstr()); 63 return (-1); 64 } 65 66 /* 67 * Check the consistency of a private key with the corresponding 68 * certificate 69 */ 70 error = SSL_CTX_check_private_key(ctx); 71 if (error < 1) { 72 syslog(LOG_ERR, "SSL: Cannot check private key: %s", ssl_errstr()); 73 return (-1); 74 } 75 76 return (0); 77 } 78 79 int 80 smtp_init_crypto(int fd, int feature) 81 { 82 SSL_CTX *ctx = NULL; 83 const SSL_METHOD *meth = NULL; 84 X509 *cert; 85 int error; 86 87 /* XXX clean up on error/close */ 88 /* Init SSL library */ 89 SSL_library_init(); 90 SSL_load_error_strings(); 91 92 meth = TLSv1_client_method(); 93 94 ctx = SSL_CTX_new(meth); 95 if (ctx == NULL) { 96 syslog(LOG_WARNING, "remote delivery deferred: SSL init failed: %s", ssl_errstr()); 97 return (1); 98 } 99 100 /* User supplied a certificate */ 101 if (config.certfile != NULL) { 102 error = init_cert_file(ctx, config.certfile); 103 if (error) { 104 syslog(LOG_WARNING, "remote delivery deferred"); 105 return (1); 106 } 107 } 108 109 /* 110 * If the user wants STARTTLS, we have to send EHLO here 111 */ 112 if (((feature & SECURETRANS) != 0) && 113 (feature & STARTTLS) != 0) { 114 /* TLS init phase, disable SSL_write */ 115 config.features |= NOSSL; 116 117 send_remote_command(fd, "EHLO %s", hostname()); 118 if (read_remote(fd, 0, NULL) == 2) { 119 send_remote_command(fd, "STARTTLS"); 120 if (read_remote(fd, 0, NULL) != 2) { 121 syslog(LOG_ERR, "remote delivery deferred:" 122 " STARTTLS not available: %s", neterr); 123 return (1); 124 } 125 } 126 /* End of TLS init phase, enable SSL_write/read */ 127 config.features &= ~NOSSL; 128 } 129 130 config.ssl = SSL_new(ctx); 131 if (config.ssl == NULL) { 132 syslog(LOG_NOTICE, "remote delivery deferred: SSL struct creation failed: %s", 133 ssl_errstr()); 134 return (1); 135 } 136 137 /* Set ssl to work in client mode */ 138 SSL_set_connect_state(config.ssl); 139 140 /* Set fd for SSL in/output */ 141 error = SSL_set_fd(config.ssl, fd); 142 if (error == 0) { 143 syslog(LOG_NOTICE, "remote delivery deferred: SSL set fd failed: %s", 144 ssl_errstr()); 145 return (1); 146 } 147 148 /* Open SSL connection */ 149 error = SSL_connect(config.ssl); 150 if (error < 0) { 151 syslog(LOG_ERR, "remote delivery deferred: SSL handshake failed fatally: %s", 152 ssl_errstr()); 153 return (1); 154 } 155 156 /* Get peer certificate */ 157 cert = SSL_get_peer_certificate(config.ssl); 158 if (cert == NULL) { 159 syslog(LOG_WARNING, "remote delivery deferred: Peer did not provide certificate: %s", 160 ssl_errstr()); 161 } 162 X509_free(cert); 163 164 return (0); 165 } 166 167 /* 168 * hmac_md5() taken out of RFC 2104. This RFC was written by H. Krawczyk, 169 * M. Bellare and R. Canetti. 170 * 171 * text pointer to data stream 172 * text_len length of data stream 173 * key pointer to authentication key 174 * key_len length of authentication key 175 * digest caller digest to be filled int 176 */ 177 void 178 hmac_md5(unsigned char *text, int text_len, unsigned char *key, int key_len, 179 caddr_t digest) 180 { 181 MD5_CTX context; 182 unsigned char k_ipad[65]; /* inner padding - 183 * key XORd with ipad 184 */ 185 unsigned char k_opad[65]; /* outer padding - 186 * key XORd with opad 187 */ 188 unsigned char tk[16]; 189 int i; 190 /* if key is longer than 64 bytes reset it to key=MD5(key) */ 191 if (key_len > 64) { 192 193 MD5_CTX tctx; 194 195 MD5_Init(&tctx); 196 MD5_Update(&tctx, key, key_len); 197 MD5_Final(tk, &tctx); 198 199 key = tk; 200 key_len = 16; 201 } 202 203 /* 204 * the HMAC_MD5 transform looks like: 205 * 206 * MD5(K XOR opad, MD5(K XOR ipad, text)) 207 * 208 * where K is an n byte key 209 * ipad is the byte 0x36 repeated 64 times 210 * 211 * opad is the byte 0x5c repeated 64 times 212 * and text is the data being protected 213 */ 214 215 /* start out by storing key in pads */ 216 bzero( k_ipad, sizeof k_ipad); 217 bzero( k_opad, sizeof k_opad); 218 bcopy( key, k_ipad, key_len); 219 bcopy( key, k_opad, key_len); 220 221 /* XOR key with ipad and opad values */ 222 for (i=0; i<64; i++) { 223 k_ipad[i] ^= 0x36; 224 k_opad[i] ^= 0x5c; 225 } 226 /* 227 * perform inner MD5 228 */ 229 MD5_Init(&context); /* init context for 1st 230 * pass */ 231 MD5_Update(&context, k_ipad, 64); /* start with inner pad */ 232 MD5_Update(&context, text, text_len); /* then text of datagram */ 233 MD5_Final(digest, &context); /* finish up 1st pass */ 234 /* 235 * perform outer MD5 236 */ 237 MD5_Init(&context); /* init context for 2nd 238 * pass */ 239 MD5_Update(&context, k_opad, 64); /* start with outer pad */ 240 MD5_Update(&context, digest, 16); /* then results of 1st 241 * hash */ 242 MD5_Final(digest, &context); /* finish up 2nd pass */ 243 } 244 245 /* 246 * CRAM-MD5 authentication 247 */ 248 int 249 smtp_auth_md5(int fd, char *login, char *password) 250 { 251 unsigned char buffer[BUF_SIZE], digest[BUF_SIZE], ascii_digest[33]; 252 char *temp; 253 int len, i; 254 static char hextab[] = "0123456789abcdef"; 255 256 temp = calloc(BUF_SIZE, 1); 257 memset(buffer, 0, sizeof(buffer)); 258 memset(digest, 0, sizeof(digest)); 259 memset(ascii_digest, 0, sizeof(ascii_digest)); 260 261 /* Send AUTH command according to RFC 2554 */ 262 send_remote_command(fd, "AUTH CRAM-MD5"); 263 if (read_remote(fd, sizeof(buffer), buffer) != 3) { 264 syslog(LOG_DEBUG, "smarthost authentication:" 265 " AUTH cram-md5 not available: %s", neterr); 266 /* if cram-md5 is not available */ 267 return (-1); 268 } 269 270 /* skip 3 char status + 1 char space */ 271 base64_decode(buffer + 4, temp); 272 hmac_md5(temp, strlen(temp), password, strlen(password), digest); 273 free(temp); 274 275 ascii_digest[32] = 0; 276 for (i = 0; i < 16; i++) { 277 ascii_digest[2*i] = hextab[digest[i] >> 4]; 278 ascii_digest[2*i+1] = hextab[digest[i] & 15]; 279 } 280 281 /* prepare answer */ 282 snprintf(buffer, BUF_SIZE, "%s %s", login, ascii_digest); 283 284 /* encode answer */ 285 len = base64_encode(buffer, strlen(buffer), &temp); 286 if (len < 0) { 287 syslog(LOG_ERR, "can not encode auth reply: %m"); 288 return (-1); 289 } 290 291 /* send answer */ 292 send_remote_command(fd, "%s", temp); 293 free(temp); 294 if (read_remote(fd, 0, NULL) != 2) { 295 syslog(LOG_WARNING, "remote delivery deferred:" 296 " AUTH cram-md5 failed: %s", neterr); 297 return (-2); 298 } 299 300 return (0); 301 } 302