[gssapi-openssh.git] / openssh / hostfile.c

/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * Functions for manipulating the known hosts files.
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 *
 * Copyright (c) 1999, 2000 Markus Friedl.  All rights reserved.
 * Copyright (c) 1999 Niels Provos.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 "includes.h"
RCSID("$OpenBSD: hostfile.c,v 1.32 2003/11/10 16:23:41 jakob Exp $");

#include "packet.h"
#include "match.h"
#include "key.h"
#include "hostfile.h"
#include "log.h"

/*
 * Parses an RSA (number of bits, e, n) or DSA key from a string.  Moves the
 * pointer over the key.  Skips any whitespace at the beginning and at end.
 */

int
hostfile_read_key(char **cpp, u_int *bitsp, Key *ret)
{
	char *cp;

	/* Skip leading whitespace. */
	for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
		;

	if (key_read(ret, &cp) != 1)
		return 0;

	/* Skip trailing whitespace. */
	for (; *cp == ' ' || *cp == '\t'; cp++)
		;

	/* Return results. */
	*cpp = cp;
	*bitsp = key_size(ret);
	return 1;
}

static int
hostfile_check_key(int bits, const Key *key, const char *host, const char *filename, int linenum)
{
	if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL)
		return 1;
	if (bits != BN_num_bits(key->rsa->n)) {
		logit("Warning: %s, line %d: keysize mismatch for host %s: "
		    "actual %d vs. announced %d.",
		    filename, linenum, host, BN_num_bits(key->rsa->n), bits);
		logit("Warning: replace %d with %d in %s, line %d.",
		    bits, BN_num_bits(key->rsa->n), filename, linenum);
	}
	return 1;
}

/*
 * Checks whether the given host (which must be in all lowercase) is already
 * in the list of our known hosts. Returns HOST_OK if the host is known and
 * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED
 * if the host is known but used to have a different host key.
 *
 * If no 'key' has been specified and a key of type 'keytype' is known
 * for the specified host, then HOST_FOUND is returned.
 */

static HostStatus
check_host_in_hostfile_by_key_or_type(const char *filename,
    const char *host, const Key *key, int keytype, Key *found, int *numret)
{
	FILE *f;
	char line[8192];
	int linenum = 0;
	u_int kbits;
	char *cp, *cp2;
	HostStatus end_return;

	debug3("check_host_in_hostfile: filename %s", filename);

	/* Open the file containing the list of known hosts. */
	f = fopen(filename, "r");
	if (!f)
		return HOST_NEW;

	/*
	 * Return value when the loop terminates.  This is set to
	 * HOST_CHANGED if we have seen a different key for the host and have
	 * not found the proper one.
	 */
	end_return = HOST_NEW;

	/* Go through the file. */
	while (fgets(line, sizeof(line), f)) {
		cp = line;
		linenum++;

		/* Skip any leading whitespace, comments and empty lines. */
		for (; *cp == ' ' || *cp == '\t'; cp++)
			;
		if (!*cp || *cp == '#' || *cp == '\n')
			continue;

		/* Find the end of the host name portion. */
		for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
			;

		/* Check if the host name matches. */
		if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1)
			continue;

		/* Got a match.  Skip host name. */
		cp = cp2;

		/*
		 * Extract the key from the line.  This will skip any leading
		 * whitespace.  Ignore badly formatted lines.
		 */
		if (!hostfile_read_key(&cp, &kbits, found))
			continue;

		if (numret != NULL)
			*numret = linenum;

		if (key == NULL) {
			/* we found a key of the requested type */
			if (found->type == keytype)
				return HOST_FOUND;
			continue;
		}

		if (!hostfile_check_key(kbits, found, host, filename, linenum))
			continue;

		/* Check if the current key is the same as the given key. */
		if (key_equal(key, found)) {
			/* Ok, they match. */
			debug3("check_host_in_hostfile: match line %d", linenum);
			fclose(f);
			return HOST_OK;
		}
		/*
		 * They do not match.  We will continue to go through the
		 * file; however, we note that we will not return that it is
		 * new.
		 */
		end_return = HOST_CHANGED;
	}
	/* Clear variables and close the file. */
	fclose(f);

	/*
	 * Return either HOST_NEW or HOST_CHANGED, depending on whether we
	 * saw a different key for the host.
	 */
	return end_return;
}

HostStatus
check_host_in_hostfile(const char *filename, const char *host, const Key *key,
    Key *found, int *numret)
{
	if (key == NULL)
		fatal("no key to look up");
	return (check_host_in_hostfile_by_key_or_type(filename, host, key, 0,
	    found, numret));
}

int
lookup_key_in_hostfile_by_type(const char *filename, const char *host,
    int keytype, Key *found, int *numret)
{
	return (check_host_in_hostfile_by_key_or_type(filename, host, NULL,
	    keytype, found, numret) == HOST_FOUND);
}

/*
 * Appends an entry to the host file.  Returns false if the entry could not
 * be appended.
 */

int
add_host_to_hostfile(const char *filename, const char *host, const Key *key)
{
	FILE *f;
	int success = 0;
	if (key == NULL)
		return 1;	/* XXX ? */
	f = fopen(filename, "a");
	if (!f)
		return 0;
	fprintf(f, "%s ", host);
	if (key_write(key, f)) {
		success = 1;
	} else {
		error("add_host_to_hostfile: saving key in %s failed", filename);
	}
	fprintf(f, "\n");
	fclose(f);
	return success;
}
Commit	Line	Data
3c0ef626	1	/*
	2	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	3	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	4	* All rights reserved
	5	* Functions for manipulating the known hosts files.
	6	*
	7	* As far as I am concerned, the code I have written for this software
	8	* can be used freely for any purpose. Any derived versions of this
	9	* software must be clearly marked as such, and if the derived work is
	10	* incompatible with the protocol description in the RFC file, it must be
	11	* called by a name other than "ssh" or "Secure Shell".
	12	*
	13	*
	14	* Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
	15	* Copyright (c) 1999 Niels Provos. All rights reserved.
	16	*
	17	* Redistribution and use in source and binary forms, with or without
	18	* modification, are permitted provided that the following conditions
	19	* are met:
	20	* 1. Redistributions of source code must retain the above copyright
	21	* notice, this list of conditions and the following disclaimer.
	22	* 2. Redistributions in binary form must reproduce the above copyright
	23	* notice, this list of conditions and the following disclaimer in the
	24	* documentation and/or other materials provided with the distribution.
	25	*
	26	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	27	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	28	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	29	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	30	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	31	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	32	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	33	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	34	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	35	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	36	*/
	37
	38	#include "includes.h"
12408a1b	39	RCSID("$OpenBSD: hostfile.c,v 1.32 2003/11/10 16:23:41 jakob Exp $");
3c0ef626	40
	41	#include "packet.h"
	42	#include "match.h"
	43	#include "key.h"
	44	#include "hostfile.h"
	45	#include "log.h"
	46
	47	/*
	48	* Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
	49	* pointer over the key. Skips any whitespace at the beginning and at end.
	50	*/
	51
e9a17296	52	int
3c0ef626	53	hostfile_read_key(char *cpp, u_int bitsp, Key *ret)
	54	{
	55	char *cp;
	56
	57	/* Skip leading whitespace. */
	58	for (cp = cpp; cp == ' ' \|\| *cp == '\t'; cp++)
	59	;
	60
	61	if (key_read(ret, &cp) != 1)
	62	return 0;
	63
	64	/* Skip trailing whitespace. */
	65	for (; cp == ' ' \|\| cp == '\t'; cp++)
	66	;
	67
	68	/* Return results. */
	69	*cpp = cp;
	70	*bitsp = key_size(ret);
	71	return 1;
	72	}
	73
3c0ef626	74	static int
12408a1b	75	hostfile_check_key(int bits, const Key key, const char host, const char *filename, int linenum)
3c0ef626	76	{
	77	if (key == NULL \|\| key->type != KEY_RSA1 \|\| key->rsa == NULL)
	78	return 1;
	79	if (bits != BN_num_bits(key->rsa->n)) {
0fff78ff	80	logit("Warning: %s, line %d: keysize mismatch for host %s: "
3c0ef626	81	"actual %d vs. announced %d.",
3c0ef626	82	filename, linenum, host, BN_num_bits(key->rsa->n), bits);
0fff78ff	83	logit("Warning: replace %d with %d in %s, line %d.",
3c0ef626	84	bits, BN_num_bits(key->rsa->n), filename, linenum);
	85	}
	86	return 1;
	87	}
	88
	89	/*
	90	* Checks whether the given host (which must be in all lowercase) is already
	91	* in the list of our known hosts. Returns HOST_OK if the host is known and
	92	* has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED
	93	* if the host is known but used to have a different host key.
41b2f314	94	*
	95	* If no 'key' has been specified and a key of type 'keytype' is known
	96	* for the specified host, then HOST_FOUND is returned.
3c0ef626	97	*/
3c0ef626	98
41b2f314	99	static HostStatus
41b2f314	100	check_host_in_hostfile_by_key_or_type(const char *filename,
12408a1b	101	const char host, const Key key, int keytype, Key found, int numret)
3c0ef626	102	{
	103	FILE *f;
	104	char line[8192];
	105	int linenum = 0;
	106	u_int kbits;
	107	char cp, cp2;
	108	HostStatus end_return;
	109
	110	debug3("check_host_in_hostfile: filename %s", filename);
41b2f314	111
3c0ef626	112	/* Open the file containing the list of known hosts. */
	113	f = fopen(filename, "r");
	114	if (!f)
	115	return HOST_NEW;
	116
	117	/*
	118	* Return value when the loop terminates. This is set to
	119	* HOST_CHANGED if we have seen a different key for the host and have
	120	* not found the proper one.
	121	*/
	122	end_return = HOST_NEW;
	123
	124	/* Go through the file. */
	125	while (fgets(line, sizeof(line), f)) {
	126	cp = line;
	127	linenum++;
	128
	129	/* Skip any leading whitespace, comments and empty lines. */
	130	for (; cp == ' ' \|\| cp == '\t'; cp++)
	131	;
	132	if (!cp \|\| cp == '#' \|\| *cp == '\n')
	133	continue;
	134
	135	/* Find the end of the host name portion. */
	136	for (cp2 = cp; cp2 && cp2 != ' ' && *cp2 != '\t'; cp2++)
	137	;
	138
	139	/* Check if the host name matches. */
	140	if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1)
	141	continue;
	142
	143	/* Got a match. Skip host name. */
	144	cp = cp2;
	145
	146	/*
	147	* Extract the key from the line. This will skip any leading
	148	* whitespace. Ignore badly formatted lines.
	149	*/
	150	if (!hostfile_read_key(&cp, &kbits, found))
	151	continue;
3c0ef626	152
	153	if (numret != NULL)
	154	*numret = linenum;
	155
41b2f314	156	if (key == NULL) {
	157	/* we found a key of the requested type */
	158	if (found->type == keytype)
	159	return HOST_FOUND;
	160	continue;
	161	}
	162
	163	if (!hostfile_check_key(kbits, found, host, filename, linenum))
	164	continue;
	165
3c0ef626	166	/* Check if the current key is the same as the given key. */
	167	if (key_equal(key, found)) {
	168	/* Ok, they match. */
	169	debug3("check_host_in_hostfile: match line %d", linenum);
	170	fclose(f);
	171	return HOST_OK;
	172	}
	173	/*
	174	* They do not match. We will continue to go through the
	175	* file; however, we note that we will not return that it is
	176	* new.
	177	*/
	178	end_return = HOST_CHANGED;
	179	}
	180	/* Clear variables and close the file. */
	181	fclose(f);
	182
	183	/*
	184	* Return either HOST_NEW or HOST_CHANGED, depending on whether we
	185	* saw a different key for the host.
	186	*/
	187	return end_return;
	188	}
	189
41b2f314	190	HostStatus
12408a1b	191	check_host_in_hostfile(const char filename, const char host, const Key *key,
41b2f314	192	Key found, int numret)
	193	{
	194	if (key == NULL)
	195	fatal("no key to look up");
	196	return (check_host_in_hostfile_by_key_or_type(filename, host, key, 0,
	197	found, numret));
	198	}
	199
	200	int
	201	lookup_key_in_hostfile_by_type(const char filename, const char host,
	202	int keytype, Key found, int numret)
	203	{
	204	return (check_host_in_hostfile_by_key_or_type(filename, host, NULL,
	205	keytype, found, numret) == HOST_FOUND);
	206	}
	207
3c0ef626	208	/*
	209	* Appends an entry to the host file. Returns false if the entry could not
	210	* be appended.
	211	*/
	212
	213	int
12408a1b	214	add_host_to_hostfile(const char filename, const char host, const Key *key)
3c0ef626	215	{
	216	FILE *f;
	217	int success = 0;
	218	if (key == NULL)
	219	return 1; /* XXX ? */
	220	f = fopen(filename, "a");
	221	if (!f)
	222	return 0;
	223	fprintf(f, "%s ", host);
	224	if (key_write(key, f)) {
	225	success = 1;
	226	} else {
	227	error("add_host_to_hostfile: saving key in %s failed", filename);
	228	}
	229	fprintf(f, "\n");
	230	fclose(f);
	231	return success;
	232	}