2 * Copyright (c) 2008 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthias Schmidt <matthias@dragonflybsd.org>, University of Marburg,
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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
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.
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
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>
48 init_cert_file(SSL_CTX *ctx, const char *path)
52 /* Load certificate into ctx */
53 error = SSL_CTX_use_certificate_chain_file(ctx, path);
55 syslog(LOG_ERR, "SSL: Cannot load certificate `%s': %s", path, ssl_errstr());
59 /* Add private key to ctx */
60 error = SSL_CTX_use_PrivateKey_file(ctx, path, SSL_FILETYPE_PEM);
62 syslog(LOG_ERR, "SSL: Cannot load private key `%s': %s", path, ssl_errstr());
67 * Check the consistency of a private key with the corresponding
70 error = SSL_CTX_check_private_key(ctx);
72 syslog(LOG_ERR, "SSL: Cannot check private key: %s", ssl_errstr());
80 smtp_init_crypto(int fd, int feature)
83 const SSL_METHOD *meth = NULL;
87 /* XXX clean up on error/close */
88 /* Init SSL library */
90 SSL_load_error_strings();
92 meth = TLSv1_client_method();
94 ctx = SSL_CTX_new(meth);
96 syslog(LOG_WARNING, "remote delivery deferred: SSL init failed: %s", ssl_errstr());
100 /* User supplied a certificate */
101 if (config.certfile != NULL) {
102 error = init_cert_file(ctx, config.certfile);
104 syslog(LOG_WARNING, "remote delivery deferred");
110 * If the user wants STARTTLS, we have to send EHLO here
112 if (((feature & SECURETRANS) != 0) &&
113 (feature & STARTTLS) != 0) {
114 /* TLS init phase, disable SSL_write */
115 config.features |= NOSSL;
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 if ((feature & TLS_OPP) == 0) {
122 syslog(LOG_ERR, "remote delivery deferred: STARTTLS not available: %s", neterr);
125 syslog(LOG_INFO, "in opportunistic TLS mode, STARTTLS not available: %s", neterr);
130 /* End of TLS init phase, enable SSL_write/read */
131 config.features &= ~NOSSL;
134 config.ssl = SSL_new(ctx);
135 if (config.ssl == NULL) {
136 syslog(LOG_NOTICE, "remote delivery deferred: SSL struct creation failed: %s",
141 /* Set ssl to work in client mode */
142 SSL_set_connect_state(config.ssl);
144 /* Set fd for SSL in/output */
145 error = SSL_set_fd(config.ssl, fd);
147 syslog(LOG_NOTICE, "remote delivery deferred: SSL set fd failed: %s",
152 /* Open SSL connection */
153 error = SSL_connect(config.ssl);
155 syslog(LOG_ERR, "remote delivery deferred: SSL handshake failed fatally: %s",
160 /* Get peer certificate */
161 cert = SSL_get_peer_certificate(config.ssl);
163 syslog(LOG_WARNING, "remote delivery deferred: Peer did not provide certificate: %s",
172 * hmac_md5() taken out of RFC 2104. This RFC was written by H. Krawczyk,
173 * M. Bellare and R. Canetti.
175 * text pointer to data stream
176 * text_len length of data stream
177 * key pointer to authentication key
178 * key_len length of authentication key
179 * digest caller digest to be filled int
182 hmac_md5(unsigned char *text, int text_len, unsigned char *key, int key_len,
183 unsigned char* digest)
186 unsigned char k_ipad[65]; /* inner padding -
189 unsigned char k_opad[65]; /* outer padding -
192 unsigned char tk[16];
194 /* if key is longer than 64 bytes reset it to key=MD5(key) */
200 MD5_Update(&tctx, key, key_len);
201 MD5_Final(tk, &tctx);
208 * the HMAC_MD5 transform looks like:
210 * MD5(K XOR opad, MD5(K XOR ipad, text))
212 * where K is an n byte key
213 * ipad is the byte 0x36 repeated 64 times
215 * opad is the byte 0x5c repeated 64 times
216 * and text is the data being protected
219 /* start out by storing key in pads */
220 bzero( k_ipad, sizeof k_ipad);
221 bzero( k_opad, sizeof k_opad);
222 bcopy( key, k_ipad, key_len);
223 bcopy( key, k_opad, key_len);
225 /* XOR key with ipad and opad values */
226 for (i=0; i<64; i++) {
233 MD5_Init(&context); /* init context for 1st
235 MD5_Update(&context, k_ipad, 64); /* start with inner pad */
236 MD5_Update(&context, text, text_len); /* then text of datagram */
237 MD5_Final(digest, &context); /* finish up 1st pass */
241 MD5_Init(&context); /* init context for 2nd
243 MD5_Update(&context, k_opad, 64); /* start with outer pad */
244 MD5_Update(&context, digest, 16); /* then results of 1st
246 MD5_Final(digest, &context); /* finish up 2nd pass */
250 * CRAM-MD5 authentication
253 smtp_auth_md5(int fd, char *login, char *password)
255 unsigned char digest[BUF_SIZE];
256 char buffer[BUF_SIZE], ascii_digest[33];
259 static char hextab[] = "0123456789abcdef";
261 temp = calloc(BUF_SIZE, 1);
262 memset(buffer, 0, sizeof(buffer));
263 memset(digest, 0, sizeof(digest));
264 memset(ascii_digest, 0, sizeof(ascii_digest));
266 /* Send AUTH command according to RFC 2554 */
267 send_remote_command(fd, "AUTH CRAM-MD5");
268 if (read_remote(fd, sizeof(buffer), buffer) != 3) {
269 syslog(LOG_DEBUG, "smarthost authentication:"
270 " AUTH cram-md5 not available: %s", neterr);
271 /* if cram-md5 is not available */
276 /* skip 3 char status + 1 char space */
277 base64_decode(buffer + 4, temp);
278 hmac_md5((unsigned char *)temp, strlen(temp),
279 (unsigned char *)password, strlen(password), digest);
282 ascii_digest[32] = 0;
283 for (i = 0; i < 16; i++) {
284 ascii_digest[2*i] = hextab[digest[i] >> 4];
285 ascii_digest[2*i+1] = hextab[digest[i] & 15];
289 snprintf(buffer, BUF_SIZE, "%s %s", login, ascii_digest);
292 len = base64_encode(buffer, strlen(buffer), &temp);
294 syslog(LOG_ERR, "can not encode auth reply: %m");
299 send_remote_command(fd, "%s", temp);
301 if (read_remote(fd, 0, NULL) != 2) {
302 syslog(LOG_WARNING, "remote delivery deferred:"
303 " AUTH cram-md5 failed: %s", neterr);