352 lines
10 KiB
C
352 lines
10 KiB
C
/*
|
|
* Copyright (c) 2008 The DragonFly Project. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to The DragonFly Project
|
|
* by Matthias Schmidt <matthias@dragonflybsd.org>, University of Marburg,
|
|
* Germany.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name of The DragonFly Project nor the names of its
|
|
* contributors may be used to endorse or promote products derived
|
|
* from this software without specific, prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <openssl/x509.h>
|
|
#include <openssl/md5.h>
|
|
#include <openssl/ssl.h>
|
|
#include <openssl/err.h>
|
|
#include <openssl/pem.h>
|
|
#include <openssl/rand.h>
|
|
|
|
#include <strings.h>
|
|
#include <string.h>
|
|
#include <syslog.h>
|
|
|
|
#include "dma.h"
|
|
|
|
static int
|
|
init_cert_file(SSL_CTX *ctx, const char *path)
|
|
{
|
|
int error;
|
|
|
|
/* Load certificate into ctx */
|
|
error = SSL_CTX_use_certificate_chain_file(ctx, path);
|
|
if (error < 1) {
|
|
syslog(LOG_ERR, "SSL: Cannot load certificate `%s': %s", path, ssl_errstr());
|
|
return (-1);
|
|
}
|
|
|
|
/* Add private key to ctx */
|
|
error = SSL_CTX_use_PrivateKey_file(ctx, path, SSL_FILETYPE_PEM);
|
|
if (error < 1) {
|
|
syslog(LOG_ERR, "SSL: Cannot load private key `%s': %s", path, ssl_errstr());
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* Check the consistency of a private key with the corresponding
|
|
* certificate
|
|
*/
|
|
error = SSL_CTX_check_private_key(ctx);
|
|
if (error < 1) {
|
|
syslog(LOG_ERR, "SSL: Cannot check private key: %s", ssl_errstr());
|
|
return (-1);
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
verify_server_fingerprint(const X509 *cert)
|
|
{
|
|
unsigned char fingerprint[EVP_MAX_MD_SIZE] = {0};
|
|
unsigned int fingerprint_len = 0;
|
|
if(!X509_digest(cert, EVP_sha256(), fingerprint, &fingerprint_len)) {
|
|
syslog(LOG_WARNING, "failed to load fingerprint of server certicate: %s",
|
|
ssl_errstr());
|
|
return (1);
|
|
}
|
|
if(fingerprint_len != SHA256_DIGEST_LENGTH) {
|
|
syslog(LOG_WARNING, "sha256 fingerprint has unexpected length of %d bytes",
|
|
fingerprint_len);
|
|
return (1);
|
|
}
|
|
if(memcmp(fingerprint, config.fingerprint, SHA256_DIGEST_LENGTH) != 0) {
|
|
syslog(LOG_WARNING, "fingerprints do not match");
|
|
return (1);
|
|
}
|
|
syslog(LOG_DEBUG, "successfully verified server certificate fingerprint");
|
|
return (0);
|
|
}
|
|
|
|
int
|
|
smtp_init_crypto(int fd, int feature, struct smtp_features* features)
|
|
{
|
|
SSL_CTX *ctx = NULL;
|
|
#if (OPENSSL_VERSION_NUMBER >= 0x00909000L)
|
|
const SSL_METHOD *meth = NULL;
|
|
#else
|
|
SSL_METHOD *meth = NULL;
|
|
#endif
|
|
X509 *cert;
|
|
int error;
|
|
|
|
/* XXX clean up on error/close */
|
|
/* Init SSL library */
|
|
SSL_library_init();
|
|
SSL_load_error_strings();
|
|
|
|
// Allow any possible version
|
|
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
|
|
meth = TLS_client_method();
|
|
#else
|
|
meth = SSLv23_client_method();
|
|
#endif
|
|
|
|
ctx = SSL_CTX_new(meth);
|
|
if (ctx == NULL) {
|
|
syslog(LOG_WARNING, "remote delivery deferred: SSL init failed: %s", ssl_errstr());
|
|
return (1);
|
|
}
|
|
|
|
/* User supplied a certificate */
|
|
if (config.certfile != NULL) {
|
|
error = init_cert_file(ctx, config.certfile);
|
|
if (error) {
|
|
syslog(LOG_WARNING, "remote delivery deferred");
|
|
return (1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the user wants STARTTLS, we have to send EHLO here
|
|
*/
|
|
if (((feature & SECURETRANSFER) != 0) &&
|
|
(feature & STARTTLS) != 0) {
|
|
/* TLS init phase, disable SSL_write */
|
|
config.features |= NOSSL;
|
|
|
|
if (perform_server_greeting(fd, features) == 0) {
|
|
send_remote_command(fd, "STARTTLS");
|
|
if (read_remote(fd, 0, NULL) != 2) {
|
|
if ((feature & TLS_OPP) == 0) {
|
|
syslog(LOG_ERR, "remote delivery deferred: STARTTLS not available: %s", neterr);
|
|
return (1);
|
|
} else {
|
|
syslog(LOG_INFO, "in opportunistic TLS mode, STARTTLS not available: %s", neterr);
|
|
return (0);
|
|
}
|
|
}
|
|
} else {
|
|
syslog(LOG_ERR, "remote delivery deferred: could not perform server greeting: %s",
|
|
neterr);
|
|
return (1);
|
|
}
|
|
|
|
/* End of TLS init phase, enable SSL_write/read */
|
|
config.features &= ~NOSSL;
|
|
}
|
|
|
|
config.ssl = SSL_new(ctx);
|
|
if (config.ssl == NULL) {
|
|
syslog(LOG_NOTICE, "remote delivery deferred: SSL struct creation failed: %s",
|
|
ssl_errstr());
|
|
return (1);
|
|
}
|
|
|
|
/* Set ssl to work in client mode */
|
|
SSL_set_connect_state(config.ssl);
|
|
|
|
/* Set fd for SSL in/output */
|
|
error = SSL_set_fd(config.ssl, fd);
|
|
if (error == 0) {
|
|
syslog(LOG_NOTICE, "remote delivery deferred: SSL set fd failed: %s",
|
|
ssl_errstr());
|
|
return (1);
|
|
}
|
|
|
|
/* Open SSL connection */
|
|
error = SSL_connect(config.ssl);
|
|
if (error != 1) {
|
|
syslog(LOG_ERR, "remote delivery deferred: SSL handshake failed fatally: %s",
|
|
ssl_errstr());
|
|
return (1);
|
|
}
|
|
|
|
/* Get peer certificate */
|
|
cert = SSL_get_peer_certificate(config.ssl);
|
|
if (cert == NULL) {
|
|
syslog(LOG_WARNING, "remote delivery deferred: Peer did not provide certificate: %s",
|
|
ssl_errstr());
|
|
return (1);
|
|
}
|
|
if(config.fingerprint != NULL && verify_server_fingerprint(cert)) {
|
|
X509_free(cert);
|
|
return (1);
|
|
}
|
|
X509_free(cert);
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* hmac_md5() taken out of RFC 2104. This RFC was written by H. Krawczyk,
|
|
* M. Bellare and R. Canetti.
|
|
*
|
|
* text pointer to data stream
|
|
* text_len length of data stream
|
|
* key pointer to authentication key
|
|
* key_len length of authentication key
|
|
* digest caller digest to be filled int
|
|
*/
|
|
void
|
|
hmac_md5(unsigned char *text, int text_len, unsigned char *key, int key_len,
|
|
unsigned char* digest)
|
|
{
|
|
MD5_CTX context;
|
|
unsigned char k_ipad[65]; /* inner padding -
|
|
* key XORd with ipad
|
|
*/
|
|
unsigned char k_opad[65]; /* outer padding -
|
|
* key XORd with opad
|
|
*/
|
|
unsigned char tk[16];
|
|
int i;
|
|
/* if key is longer than 64 bytes reset it to key=MD5(key) */
|
|
if (key_len > 64) {
|
|
|
|
MD5_CTX tctx;
|
|
|
|
MD5_Init(&tctx);
|
|
MD5_Update(&tctx, key, key_len);
|
|
MD5_Final(tk, &tctx);
|
|
|
|
key = tk;
|
|
key_len = 16;
|
|
}
|
|
|
|
/*
|
|
* the HMAC_MD5 transform looks like:
|
|
*
|
|
* MD5(K XOR opad, MD5(K XOR ipad, text))
|
|
*
|
|
* where K is an n byte key
|
|
* ipad is the byte 0x36 repeated 64 times
|
|
*
|
|
* opad is the byte 0x5c repeated 64 times
|
|
* and text is the data being protected
|
|
*/
|
|
|
|
/* start out by storing key in pads */
|
|
bzero( k_ipad, sizeof k_ipad);
|
|
bzero( k_opad, sizeof k_opad);
|
|
bcopy( key, k_ipad, key_len);
|
|
bcopy( key, k_opad, key_len);
|
|
|
|
/* XOR key with ipad and opad values */
|
|
for (i=0; i<64; i++) {
|
|
k_ipad[i] ^= 0x36;
|
|
k_opad[i] ^= 0x5c;
|
|
}
|
|
/*
|
|
* perform inner MD5
|
|
*/
|
|
MD5_Init(&context); /* init context for 1st
|
|
* pass */
|
|
MD5_Update(&context, k_ipad, 64); /* start with inner pad */
|
|
MD5_Update(&context, text, text_len); /* then text of datagram */
|
|
MD5_Final(digest, &context); /* finish up 1st pass */
|
|
/*
|
|
* perform outer MD5
|
|
*/
|
|
MD5_Init(&context); /* init context for 2nd
|
|
* pass */
|
|
MD5_Update(&context, k_opad, 64); /* start with outer pad */
|
|
MD5_Update(&context, digest, 16); /* then results of 1st
|
|
* hash */
|
|
MD5_Final(digest, &context); /* finish up 2nd pass */
|
|
}
|
|
|
|
/*
|
|
* CRAM-MD5 authentication
|
|
*/
|
|
int
|
|
smtp_auth_md5(int fd, char *login, char *password)
|
|
{
|
|
unsigned char digest[BUF_SIZE];
|
|
char buffer[BUF_SIZE], ascii_digest[33];
|
|
char *temp;
|
|
int len, i;
|
|
static char hextab[] = "0123456789abcdef";
|
|
|
|
temp = calloc(BUF_SIZE, 1);
|
|
memset(buffer, 0, sizeof(buffer));
|
|
memset(digest, 0, sizeof(digest));
|
|
memset(ascii_digest, 0, sizeof(ascii_digest));
|
|
|
|
/* Send AUTH command according to RFC 2554 */
|
|
send_remote_command(fd, "AUTH CRAM-MD5");
|
|
if (read_remote(fd, sizeof(buffer), buffer) != 3) {
|
|
syslog(LOG_DEBUG, "smarthost authentication:"
|
|
" AUTH cram-md5 not available: %s", neterr);
|
|
/* if cram-md5 is not available */
|
|
free(temp);
|
|
return (-1);
|
|
}
|
|
|
|
/* skip 3 char status + 1 char space */
|
|
base64_decode(buffer + 4, temp);
|
|
hmac_md5((unsigned char *)temp, strlen(temp),
|
|
(unsigned char *)password, strlen(password), digest);
|
|
free(temp);
|
|
|
|
ascii_digest[32] = 0;
|
|
for (i = 0; i < 16; i++) {
|
|
ascii_digest[2*i] = hextab[digest[i] >> 4];
|
|
ascii_digest[2*i+1] = hextab[digest[i] & 15];
|
|
}
|
|
|
|
/* prepare answer */
|
|
snprintf(buffer, BUF_SIZE, "%s %s", login, ascii_digest);
|
|
|
|
/* encode answer */
|
|
len = base64_encode(buffer, strlen(buffer), &temp);
|
|
if (len < 0) {
|
|
syslog(LOG_ERR, "can not encode auth reply: %m");
|
|
return (-1);
|
|
}
|
|
|
|
/* send answer */
|
|
send_remote_command(fd, "%s", temp);
|
|
free(temp);
|
|
if (read_remote(fd, 0, NULL) != 2) {
|
|
syslog(LOG_WARNING, "remote delivery deferred:"
|
|
" AUTH cram-md5 failed: %s", neterr);
|
|
return (-2);
|
|
}
|
|
|
|
return (0);
|
|
}
|