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 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 config->features &= ~NOSSL; 124 return (1); 125 } 126 } 127 /* End of TLS init phase, enable SSL_write/read */ 128 config->features &= ~NOSSL; 129 } 130 131 config->ssl = SSL_new(ctx); 132 if (config->ssl == NULL) { 133 syslog(LOG_NOTICE, "remote delivery deferred: SSL struct creation failed: %s", 134 ssl_errstr()); 135 return (1); 136 } 137 138 /* Set ssl to work in client mode */ 139 SSL_set_connect_state(config->ssl); 140 141 /* Set fd for SSL in/output */ 142 error = SSL_set_fd(config->ssl, fd); 143 if (error == 0) { 144 syslog(LOG_NOTICE, "remote delivery deferred: SSL set fd failed: %s", 145 ssl_errstr()); 146 return (1); 147 } 148 149 /* Open SSL connection */ 150 error = SSL_connect(config->ssl); 151 if (error < 0) { 152 syslog(LOG_ERR, "remote delivery deferred: SSL handshake failed fatally: %s", 153 ssl_errstr()); 154 return (1); 155 } 156 157 /* Get peer certificate */ 158 cert = SSL_get_peer_certificate(config->ssl); 159 if (cert == NULL) { 160 syslog(LOG_WARNING, "remote delivery deferred: Peer did not provide certificate: %s", 161 ssl_errstr()); 162 } 163 X509_free(cert); 164 165 return (0); 166 } 167 168 /* 169 * hmac_md5() taken out of RFC 2104. This RFC was written by H. Krawczyk, 170 * M. Bellare and R. Canetti. 171 * 172 * text pointer to data stream 173 * text_len length of data stream 174 * key pointer to authentication key 175 * key_len length of authentication key 176 * digest caller digest to be filled int 177 */ 178 void 179 hmac_md5(unsigned char *text, int text_len, unsigned char *key, int key_len, 180 caddr_t digest) 181 { 182 MD5_CTX context; 183 unsigned char k_ipad[65]; /* inner padding - 184 * key XORd with ipad 185 */ 186 unsigned char k_opad[65]; /* outer padding - 187 * key XORd with opad 188 */ 189 unsigned char tk[16]; 190 int i; 191 /* if key is longer than 64 bytes reset it to key=MD5(key) */ 192 if (key_len > 64) { 193 194 MD5_CTX tctx; 195 196 MD5_Init(&tctx); 197 MD5_Update(&tctx, key, key_len); 198 MD5_Final(tk, &tctx); 199 200 key = tk; 201 key_len = 16; 202 } 203 204 /* 205 * the HMAC_MD5 transform looks like: 206 * 207 * MD5(K XOR opad, MD5(K XOR ipad, text)) 208 * 209 * where K is an n byte key 210 * ipad is the byte 0x36 repeated 64 times 211 * 212 * opad is the byte 0x5c repeated 64 times 213 * and text is the data being protected 214 */ 215 216 /* start out by storing key in pads */ 217 bzero( k_ipad, sizeof k_ipad); 218 bzero( k_opad, sizeof k_opad); 219 bcopy( key, k_ipad, key_len); 220 bcopy( key, k_opad, key_len); 221 222 /* XOR key with ipad and opad values */ 223 for (i=0; i<64; i++) { 224 k_ipad[i] ^= 0x36; 225 k_opad[i] ^= 0x5c; 226 } 227 /* 228 * perform inner MD5 229 */ 230 MD5_Init(&context); /* init context for 1st 231 * pass */ 232 MD5_Update(&context, k_ipad, 64); /* start with inner pad */ 233 MD5_Update(&context, text, text_len); /* then text of datagram */ 234 MD5_Final(digest, &context); /* finish up 1st pass */ 235 /* 236 * perform outer MD5 237 */ 238 MD5_Init(&context); /* init context for 2nd 239 * pass */ 240 MD5_Update(&context, k_opad, 64); /* start with outer pad */ 241 MD5_Update(&context, digest, 16); /* then results of 1st 242 * hash */ 243 MD5_Final(digest, &context); /* finish up 2nd pass */ 244 } 245 246 /* 247 * CRAM-MD5 authentication 248 */ 249 int 250 smtp_auth_md5(int fd, char *login, char *password) 251 { 252 unsigned char buffer[BUF_SIZE], digest[BUF_SIZE], ascii_digest[33]; 253 char *temp; 254 int len, i; 255 static char hextab[] = "0123456789abcdef"; 256 257 temp = calloc(BUF_SIZE, 1); 258 memset(buffer, 0, sizeof(buffer)); 259 memset(digest, 0, sizeof(digest)); 260 memset(ascii_digest, 0, sizeof(ascii_digest)); 261 262 /* Send AUTH command according to RFC 2554 */ 263 send_remote_command(fd, "AUTH CRAM-MD5"); 264 if (read_remote(fd, sizeof(buffer), buffer) != 3) { 265 syslog(LOG_DEBUG, "smarthost authentification:" 266 " AUTH cram-md5 not available: %s", neterr); 267 /* if cram-md5 is not available */ 268 return (-1); 269 } 270 271 /* skip 3 char status + 1 char space */ 272 base64_decode(buffer + 4, temp); 273 hmac_md5(temp, strlen(temp), password, strlen(password), digest); 274 free(temp); 275 276 ascii_digest[32] = 0; 277 for (i = 0; i < 16; i++) { 278 ascii_digest[2*i] = hextab[digest[i] >> 4]; 279 ascii_digest[2*i+1] = hextab[digest[i] & 15]; 280 } 281 282 /* prepare answer */ 283 snprintf(buffer, BUF_SIZE, "%s %s", login, ascii_digest); 284 285 /* encode answer */ 286 len = base64_encode(buffer, strlen(buffer), &temp); 287 if (len < 0) { 288 syslog(LOG_ERR, "can not encode auth reply: %m"); 289 return (-1); 290 } 291 292 /* send answer */ 293 send_remote_command(fd, "%s", temp); 294 free(temp); 295 if (read_remote(fd, 0, NULL) != 2) { 296 syslog(LOG_WARNING, "remote delivery deferred:" 297 " AUTH cram-md5 failed: %s", neterr); 298 return (-2); 299 } 300 301 return (0); 302 } 303