[people/ms/dma.git] / crypto.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 <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);
}

int
smtp_init_crypto(int fd, int feature)
{
	SSL_CTX *ctx = NULL;
	SSL_METHOD *meth = NULL;
	X509 *cert;
	int error;

	/* XXX clean up on error/close */
	/* Init SSL library */
	SSL_library_init();
	SSL_load_error_strings();

	meth = TLSv1_client_method();

	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 & SECURETRANS) != 0) &&
	     (feature & STARTTLS) != 0) {
		/* TLS init phase, disable SSL_write */
		config.features |= NOSSL;

		send_remote_command(fd, "EHLO %s", hostname());
		if (read_remote(fd, 0, NULL) == 2) {
			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);
				}
			}
		}
		/* 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 < 0) {
		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());
	}
	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 */
		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);
}
Commit	Line	Data
86e4d161 MS	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.
86e4d161 MS	34	*/
86e4d161 MS	35
86e4d161	36	#include <openssl/x509.h>
bf28fcc6	37	#include <openssl/md5.h>
86e4d161 MS	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
86e4d161	47	static int
4d5af2b0	48	init_cert_file(SSL_CTX ctx, const char path)
86e4d161 MS	49	{
	50	int error;
	51
	52	/* Load certificate into ctx */
	53	error = SSL_CTX_use_certificate_chain_file(ctx, path);
	54	if (error < 1) {
4d5af2b0	55	syslog(LOG_ERR, "SSL: Cannot load certificate `%s': %s", path, ssl_errstr());
86e4d161 MS	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) {
4d5af2b0	62	syslog(LOG_ERR, "SSL: Cannot load private key `%s': %s", path, ssl_errstr());
86e4d161 MS	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) {
4d5af2b0	72	syslog(LOG_ERR, "SSL: Cannot check private key: %s", ssl_errstr());
86e4d161 MS	73	return (-1);
	74	}
	75
	76	return (0);
	77	}
	78
	79	int
4d5af2b0	80	smtp_init_crypto(int fd, int feature)
86e4d161 MS	81	{
	82	SSL_CTX *ctx = NULL;
	83	SSL_METHOD *meth = NULL;
	84	X509 *cert;
86e4d161 MS	85	int error;
86e4d161 MS	86
8aea09c9	87	/* XXX clean up on error/close */
86e4d161 MS	88	/* Init SSL library */
86e4d161 MS	89	SSL_library_init();
53885e5a	90	SSL_load_error_strings();
86e4d161 MS	91
	92	meth = TLSv1_client_method();
	93
	94	ctx = SSL_CTX_new(meth);
	95	if (ctx == NULL) {
4d5af2b0	96	syslog(LOG_WARNING, "remote delivery deferred: SSL init failed: %s", ssl_errstr());
53885e5a	97	return (1);
86e4d161 MS	98	}
	99
	100	/* User supplied a certificate */
a0c4afa6 SS	101	if (config.certfile != NULL) {
a0c4afa6 SS	102	error = init_cert_file(ctx, config.certfile);
53885e5a	103	if (error) {
4d5af2b0	104	syslog(LOG_WARNING, "remote delivery deferred");
53885e5a SS	105	return (1);
	106	}
	107	}
86e4d161 MS	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 */
a0c4afa6	115	config.features \|= NOSSL;
86e4d161 MS	116
86e4d161 MS	117	send_remote_command(fd, "EHLO %s", hostname());
bf28fcc6	118	if (read_remote(fd, 0, NULL) == 2) {
86e4d161	119	send_remote_command(fd, "STARTTLS");
bf28fcc6	120	if (read_remote(fd, 0, NULL) != 2) {
4dea15f5 PP	121	if ((feature & TLS_OPP) == 0) {
	122	syslog(LOG_ERR, "remote delivery deferred: STARTTLS not available: %s", neterr);
	123	return (1);
	124	} else {
	125	syslog(LOG_INFO, "in opportunistic TLS mode, STARTTLS not available: %s", neterr);
	126	return (0);
	127	}
86e4d161 MS	128	}
	129	}
	130	/* End of TLS init phase, enable SSL_write/read */
a0c4afa6	131	config.features &= ~NOSSL;
86e4d161 MS	132	}
86e4d161 MS	133
a0c4afa6 SS	134	config.ssl = SSL_new(ctx);
a0c4afa6 SS	135	if (config.ssl == NULL) {
4d5af2b0 SS	136	syslog(LOG_NOTICE, "remote delivery deferred: SSL struct creation failed: %s",
4d5af2b0 SS	137	ssl_errstr());
53885e5a	138	return (1);
86e4d161 MS	139	}
	140
	141	/* Set ssl to work in client mode */
a0c4afa6	142	SSL_set_connect_state(config.ssl);
86e4d161 MS	143
86e4d161 MS	144	/* Set fd for SSL in/output */
a0c4afa6	145	error = SSL_set_fd(config.ssl, fd);
86e4d161	146	if (error == 0) {
4d5af2b0 SS	147	syslog(LOG_NOTICE, "remote delivery deferred: SSL set fd failed: %s",
4d5af2b0 SS	148	ssl_errstr());
53885e5a	149	return (1);
86e4d161 MS	150	}
	151
	152	/* Open SSL connection */
a0c4afa6	153	error = SSL_connect(config.ssl);
86e4d161	154	if (error < 0) {
4d5af2b0 SS	155	syslog(LOG_ERR, "remote delivery deferred: SSL handshake failed fatally: %s",
4d5af2b0 SS	156	ssl_errstr());
53885e5a	157	return (1);
86e4d161 MS	158	}
	159
	160	/* Get peer certificate */
a0c4afa6	161	cert = SSL_get_peer_certificate(config.ssl);
86e4d161	162	if (cert == NULL) {
4d5af2b0 SS	163	syslog(LOG_WARNING, "remote delivery deferred: Peer did not provide certificate: %s",
4d5af2b0 SS	164	ssl_errstr());
86e4d161 MS	165	}
	166	X509_free(cert);
	167
	168	return (0);
	169	}
	170
bf28fcc6 MS	171	/*
	172	* hmac_md5() taken out of RFC 2104. This RFC was written by H. Krawczyk,
	173	* M. Bellare and R. Canetti.
c507d897 SW	174	*
	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
	180	*/
bf28fcc6	181	void
c507d897	182	hmac_md5(unsigned char text, int text_len, unsigned char key, int key_len,
9b921550	183	unsigned char* digest)
bf28fcc6 MS	184	{
	185	MD5_CTX context;
	186	unsigned char k_ipad[65]; /* inner padding -
	187	* key XORd with ipad
	188	*/
	189	unsigned char k_opad[65]; /* outer padding -
	190	* key XORd with opad
	191	*/
	192	unsigned char tk[16];
	193	int i;
	194	/* if key is longer than 64 bytes reset it to key=MD5(key) */
	195	if (key_len > 64) {
	196
	197	MD5_CTX tctx;
	198
	199	MD5_Init(&tctx);
	200	MD5_Update(&tctx, key, key_len);
	201	MD5_Final(tk, &tctx);
	202
	203	key = tk;
	204	key_len = 16;
	205	}
	206
	207	/*
	208	* the HMAC_MD5 transform looks like:
	209	*
	210	* MD5(K XOR opad, MD5(K XOR ipad, text))
	211	*
	212	* where K is an n byte key
	213	* ipad is the byte 0x36 repeated 64 times
	214	*
	215	* opad is the byte 0x5c repeated 64 times
	216	* and text is the data being protected
	217	*/
	218
	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);
	224
	225	/* XOR key with ipad and opad values */
	226	for (i=0; i<64; i++) {
	227	k_ipad[i] ^= 0x36;
	228	k_opad[i] ^= 0x5c;
	229	}
	230	/*
	231	* perform inner MD5
	232	*/
	233	MD5_Init(&context); /* init context for 1st
	234	* pass */
	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 */
	238	/*
	239	* perform outer MD5
	240	*/
	241	MD5_Init(&context); /* init context for 2nd
	242	* pass */
	243	MD5_Update(&context, k_opad, 64); /* start with outer pad */
	244	MD5_Update(&context, digest, 16); /* then results of 1st
	245	* hash */
	246	MD5_Final(digest, &context); /* finish up 2nd pass */
	247	}
248
86e4d161 MS	249	/*
86e4d161 MS	250	* CRAM-MD5 authentication
86e4d161 MS	251	*/
86e4d161 MS	252	int
4d5af2b0	253	smtp_auth_md5(int fd, char login, char password)
86e4d161	254	{
9b921550 SS	255	unsigned char digest[BUF_SIZE];
9b921550 SS	256	char buffer[BUF_SIZE], ascii_digest[33];
bf28fcc6 MS	257	char *temp;
	258	int len, i;
	259	static char hextab[] = "0123456789abcdef";
	260
	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));
	265
	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) {
904bbe47	269	syslog(LOG_DEBUG, "smarthost authentication:"
4d5af2b0	270	" AUTH cram-md5 not available: %s", neterr);
bf28fcc6 MS	271	/* if cram-md5 is not available */
	272	return (-1);
	273	}
	274
	275	/* skip 3 char status + 1 char space */
	276	base64_decode(buffer + 4, temp);
9b921550 SS	277	hmac_md5((unsigned char *)temp, strlen(temp),
9b921550 SS	278	(unsigned char *)password, strlen(password), digest);
196b1b32	279	free(temp);
bf28fcc6 MS	280
	281	ascii_digest[32] = 0;
	282	for (i = 0; i < 16; i++) {
	283	ascii_digest[2*i] = hextab[digest[i] >> 4];
	284	ascii_digest[2*i+1] = hextab[digest[i] & 15];
	285	}
	286
	287	/* prepare answer */
	288	snprintf(buffer, BUF_SIZE, "%s %s", login, ascii_digest);
	289
bf28fcc6 MS	290	/* encode answer */
bf28fcc6 MS	291	len = base64_encode(buffer, strlen(buffer), &temp);
196b1b32	292	if (len < 0) {
4d5af2b0	293	syslog(LOG_ERR, "can not encode auth reply: %m");
bf28fcc6	294	return (-1);
196b1b32	295	}
bf28fcc6 MS	296
	297	/* send answer */
	298	send_remote_command(fd, "%s", temp);
196b1b32	299	free(temp);
bf28fcc6	300	if (read_remote(fd, 0, NULL) != 2) {
4d5af2b0 SS	301	syslog(LOG_WARNING, "remote delivery deferred:"
4d5af2b0 SS	302	" AUTH cram-md5 failed: %s", neterr);
bf28fcc6 MS	303	return (-2);
	304	}
	305
	306	return (0);
86e4d161	307	}