[openssh.git] / auth2.c

/*
 * Copyright (c) 2000 Markus Friedl.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Markus Friedl.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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: auth2.c,v 1.8 2000/05/08 17:42:24 markus Exp $");

#include <openssl/dsa.h>
#include <openssl/rsa.h>
#include <openssl/evp.h>

#include "xmalloc.h"
#include "rsa.h"
#include "ssh.h"
#include "pty.h"
#include "packet.h"
#include "buffer.h"
#include "cipher.h"
#include "servconf.h"
#include "compat.h"
#include "channels.h"
#include "bufaux.h"
#include "ssh2.h"
#include "auth.h"
#include "session.h"
#include "dispatch.h"
#include "auth.h"
#include "key.h"
#include "kex.h"

#include "dsa.h"
#include "uidswap.h"

/* import */
extern ServerOptions options;
extern unsigned char *session_id2;
extern int session_id2_len;

/* protocol */

void	input_service_request(int type, int plen);
void	input_userauth_request(int type, int plen);
void	protocol_error(int type, int plen);

/* auth */
int	ssh2_auth_none(struct passwd *pw);
int	ssh2_auth_password(struct passwd *pw);
int	ssh2_auth_pubkey(struct passwd *pw, unsigned char *raw, unsigned int rlen);

/* helper */
struct passwd*	 auth_set_user(char *u, char *s);
int	user_dsa_key_allowed(struct passwd *pw, Key *key);

typedef struct Authctxt Authctxt;
struct Authctxt {
	char *user;
	char *service;
	struct passwd pw;
	int valid;
};
static Authctxt	*authctxt = NULL;
static int userauth_success = 0;

/*
 * loop until userauth_success == TRUE
 */

void
do_authentication2()
{
	/* turn off skey/kerberos, not supported by SSH2 */
#ifdef SKEY
	options.skey_authentication = 0;
#endif
#ifdef KRB4
	options.kerberos_authentication = 0;
#endif

	dispatch_init(&protocol_error);
	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
	dispatch_run(DISPATCH_BLOCK, &userauth_success);
	do_authenticated2();
}

void
protocol_error(int type, int plen)
{
	log("auth: protocol error: type %d plen %d", type, plen);
	packet_start(SSH2_MSG_UNIMPLEMENTED);
	packet_put_int(0);
	packet_send();
	packet_write_wait();
}

void
input_service_request(int type, int plen)
{
	unsigned int len;
	int accept = 0;
	char *service = packet_get_string(&len);
	packet_done();

	if (strcmp(service, "ssh-userauth") == 0) {
		if (!userauth_success) {
			accept = 1;
			/* now we can handle user-auth requests */
			dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
		}
	}
	/* XXX all other service requests are denied */

	if (accept) {
		packet_start(SSH2_MSG_SERVICE_ACCEPT);
		packet_put_cstring(service);
		packet_send();
		packet_write_wait();
	} else {
		debug("bad service request %s", service);
		packet_disconnect("bad service request %s", service);
	}
	xfree(service);
}

void
input_userauth_request(int type, int plen)
{
	static void (*authlog) (const char *fmt,...) = verbose;
	static int attempt = 0;
	unsigned int len, rlen;
	int authenticated = 0;
	char *raw, *user, *service, *method, *authmsg = NULL;
	struct passwd *pw;
#ifdef WITH_AIXAUTHENTICATE
	extern char *aixloginmsg;
#endif /* WITH_AIXAUTHENTICATE */

	raw = packet_get_raw(&rlen);
	if (plen != rlen)
		fatal("plen != rlen");
	user = packet_get_string(&len);
	service = packet_get_string(&len);
	method = packet_get_string(&len);
	if (++attempt == AUTH_FAIL_MAX) {
#ifdef WITH_AIXAUTHENTICATE 
		loginfailed(user,get_canonical_hostname(),"ssh");
#endif /* WITH_AIXAUTHENTICATE */
		packet_disconnect("too many failed userauth_requests");
	}
	debug("userauth-request for user %s service %s method %s", user, service, method);

	/* XXX we only allow the ssh-connection service */
	pw = auth_set_user(user, service);
	if (pw && strcmp(service, "ssh-connection")==0) {
		if (strcmp(method, "none") == 0) {
			authenticated =	ssh2_auth_none(pw);
		} else if (strcmp(method, "password") == 0) {
			authenticated =	ssh2_auth_password(pw);
		} else if (strcmp(method, "publickey") == 0) {
			authenticated =	ssh2_auth_pubkey(pw, raw, rlen);
		}
	}
	if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
		authenticated = 0;
		log("ROOT LOGIN REFUSED FROM %.200s",
		    get_canonical_hostname());
	}

#ifdef USE_PAM
		if (authenticated && !do_pam_account(pw->pw_name, NULL))
			authenticated = 0;
#endif /* USE_PAM */

	/* Raise logging level */
	if (authenticated == 1 ||
	    attempt == AUTH_FAIL_LOG ||
	    strcmp(method, "password") == 0)
		authlog = log;

	/* Log before sending the reply */
	if (authenticated == 1) {
		authmsg = "Accepted";
	} else if (authenticated == 0) {
		authmsg = "Failed";
	} else {
		authmsg = "Postponed";
	}
	authlog("%s %s for %.200s from %.200s port %d ssh2",
		authmsg,
		method,
		pw && pw->pw_uid == 0 ? "ROOT" : user,
		get_remote_ipaddr(),
		get_remote_port());

	/* XXX todo: check if multiple auth methods are needed */
	if (authenticated == 1) {
#ifdef WITH_AIXAUTHENTICATE
		/* We don't have a pty yet, so just label the line as "ssh" */
		if (loginsuccess(user,get_canonical_hostname(),"ssh",
				&aixloginmsg) < 0)
			aixloginmsg = NULL;
#endif /* WITH_AIXAUTHENTICATE */
		/* turn off userauth */
		dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
		packet_start(SSH2_MSG_USERAUTH_SUCCESS);
		packet_send();
		packet_write_wait();
		/* now we can break out */
		userauth_success = 1;
	} else if (authenticated == 0) {
		packet_start(SSH2_MSG_USERAUTH_FAILURE);
		packet_put_cstring("publickey,password");	/* XXX dynamic */
		packet_put_char(0);				/* XXX partial success, unused */
		packet_send();
		packet_write_wait();
	}

	xfree(service);
	xfree(user);
	xfree(method);
}

int
ssh2_auth_none(struct passwd *pw)
{
	packet_done();
#ifdef USE_PAM
	return auth_pam_password(pw, "");
#else /* USE_PAM */
	return auth_password(pw, "");
#endif /* USE_PAM */
}
int
ssh2_auth_password(struct passwd *pw)
{
	char *password;
	int authenticated = 0;
	int change;
	unsigned int len;
	change = packet_get_char();
	if (change)
		log("password change not supported");
	password = packet_get_string(&len);
	packet_done();
	if (options.password_authentication &&
#ifdef USE_PAM
	    auth_pam_password(pw, password) == 1)
#else /* USE_PAM */
	    auth_password(pw, password) == 1)
#endif /* USE_PAM */
		authenticated = 1;
	memset(password, 0, len);
	xfree(password);
	return authenticated;
}
int
ssh2_auth_pubkey(struct passwd *pw, unsigned char *raw, unsigned int rlen)
{
	Buffer b;
	Key *key;
	char *pkalg, *pkblob, *sig;
	unsigned int alen, blen, slen;
	int have_sig;
	int authenticated = 0;

	if (options.dsa_authentication == 0) {
		debug("pubkey auth disabled");
		return 0;
	}
	if (datafellows & SSH_BUG_PUBKEYAUTH) {
		log("bug compatibility with ssh-2.0.13 pubkey not implemented");
		return 0;
	}
	have_sig = packet_get_char();
	pkalg = packet_get_string(&alen);
	if (strcmp(pkalg, KEX_DSS) != 0) {
		xfree(pkalg);
		log("bad pkalg %s", pkalg);	/*XXX*/
		return 0;
	}
	pkblob = packet_get_string(&blen);
	key = dsa_key_from_blob(pkblob, blen);
	if (key != NULL) {
		if (have_sig) {
			sig = packet_get_string(&slen);
			packet_done();
			buffer_init(&b);
			buffer_append(&b, session_id2, session_id2_len);
			buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
			if (slen + 4 > rlen)
				fatal("bad rlen/slen");
			buffer_append(&b, raw, rlen - slen - 4);
#ifdef DEBUG_DSS
			buffer_dump(&b);
#endif
			/* test for correct signature */
			if (user_dsa_key_allowed(pw, key) &&
			    dsa_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
				authenticated = 1;
			buffer_clear(&b);
			xfree(sig);
		} else {
			packet_done();
			debug("test key...");
			/* test whether pkalg/pkblob are acceptable */
			/* XXX fake reply and always send PK_OK ? */
			/*
			 * XXX this allows testing whether a user is allowed
			 * to login: if you happen to have a valid pubkey this
			 * message is sent. the message is NEVER sent at all
			 * if a user is not allowed to login. is this an
			 * issue? -markus
			 */
			if (user_dsa_key_allowed(pw, key)) {
				packet_start(SSH2_MSG_USERAUTH_PK_OK);
				packet_put_string(pkalg, alen);
				packet_put_string(pkblob, blen);
				packet_send();
				packet_write_wait();
				authenticated = -1;
			}
		}
		key_free(key);
	}
	xfree(pkalg);
	xfree(pkblob);
	return authenticated;
}

/* set and get current user */

struct passwd*
auth_get_user(void)
{
	return (authctxt != NULL && authctxt->valid) ? &authctxt->pw : NULL;
}

struct passwd*
auth_set_user(char *u, char *s)
{
	struct passwd *pw, *copy;

	if (authctxt == NULL) {
		authctxt = xmalloc(sizeof(*authctxt));
		authctxt->valid = 0;
		authctxt->user = xstrdup(u);
		authctxt->service = xstrdup(s);
		setproctitle("%s", u);
		pw = getpwnam(u);
		if (!pw || !allowed_user(pw)) {
			log("auth_set_user: illegal user %s", u);
			return NULL;
		}
#ifdef USE_PAM
		start_pam(pw);
#endif
		copy = &authctxt->pw;
		memset(copy, 0, sizeof(*copy));
		copy->pw_name = xstrdup(pw->pw_name);
		copy->pw_passwd = xstrdup(pw->pw_passwd);
		copy->pw_uid = pw->pw_uid;
		copy->pw_gid = pw->pw_gid;
		copy->pw_dir = xstrdup(pw->pw_dir);
		copy->pw_shell = xstrdup(pw->pw_shell);
		authctxt->valid = 1;
	} else {
		if (strcmp(u, authctxt->user) != 0 ||
		    strcmp(s, authctxt->service) != 0) {
			log("auth_set_user: missmatch: (%s,%s)!=(%s,%s)",
			    u, s, authctxt->user, authctxt->service);
			return NULL;
		}
	}
	return auth_get_user();
}

/* return 1 if user allows given key */
int
user_dsa_key_allowed(struct passwd *pw, Key *key)
{
	char line[8192], file[1024];
	int found_key = 0;
	unsigned int bits = -1;
	FILE *f;
	unsigned long linenum = 0;
	struct stat st;
	Key *found;

	/* Temporarily use the user's uid. */
	temporarily_use_uid(pw->pw_uid);

	/* The authorized keys. */
	snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
	    SSH_USER_PERMITTED_KEYS2);

	/* Fail quietly if file does not exist */
	if (stat(file, &st) < 0) {
		/* Restore the privileged uid. */
		restore_uid();
		return 0;
	}
	/* Open the file containing the authorized keys. */
	f = fopen(file, "r");
	if (!f) {
		/* Restore the privileged uid. */
		restore_uid();
		return 0;
	}
	if (options.strict_modes) {
		int fail = 0;
		char buf[1024];
		/* Check open file in order to avoid open/stat races */
		if (fstat(fileno(f), &st) < 0 ||
		    (st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
		    (st.st_mode & 022) != 0) {
			snprintf(buf, sizeof buf, "DSA authentication refused for %.100s: "
			    "bad ownership or modes for '%s'.", pw->pw_name, file);
			fail = 1;
		} else {
			/* Check path to SSH_USER_PERMITTED_KEYS */
			int i;
			static const char *check[] = {
				"", SSH_USER_DIR, NULL
			};
			for (i = 0; check[i]; i++) {
				snprintf(line, sizeof line, "%.500s/%.100s",
				    pw->pw_dir, check[i]);
				if (stat(line, &st) < 0 ||
				    (st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
				    (st.st_mode & 022) != 0) {
					snprintf(buf, sizeof buf,
					    "DSA authentication refused for %.100s: "
					    "bad ownership or modes for '%s'.",
					    pw->pw_name, line);
					fail = 1;
					break;
				}
			}
		}
		if (fail) {
			log(buf);
			fclose(f);
			restore_uid();
			return 0;
		}
	}
	found_key = 0;
	found = key_new(KEY_DSA);

	while (fgets(line, sizeof(line), f)) {
		char *cp;
		linenum++;
		/* Skip leading whitespace, empty and comment lines. */
		for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
			;
		if (!*cp || *cp == '\n' || *cp == '#')
			continue;
		bits = key_read(found, &cp);
		if (bits == 0)
			continue;
		if (key_equal(found, key)) {
			found_key = 1;
			debug("matching key found: file %s, line %ld",
			    file, linenum);
			break;
		}
	}
	restore_uid();
	fclose(f);
	key_free(found);
	return found_key;
}
Commit	Line	Data
a306f2dd	1	/*
	2	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	* 3. All advertising materials mentioning features or use of this software
	13	* must display the following acknowledgement:
	14	* This product includes software developed by Markus Friedl.
	15	* 4. The name of the author may not be used to endorse or promote products
	16	* derived from this software without specific prior written permission.
	17	*
	18	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	19	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	20	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	21	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	22	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	23	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	24	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	25	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	26	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	27	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	28	*/
	29	#include "includes.h"
d0c832f3	30	RCSID("$OpenBSD: auth2.c,v 1.8 2000/05/08 17:42:24 markus Exp $");
a306f2dd	31
	32	#include <openssl/dsa.h>
	33	#include <openssl/rsa.h>
	34	#include <openssl/evp.h>
	35
	36	#include "xmalloc.h"
	37	#include "rsa.h"
	38	#include "ssh.h"
	39	#include "pty.h"
	40	#include "packet.h"
	41	#include "buffer.h"
	42	#include "cipher.h"
	43	#include "servconf.h"
	44	#include "compat.h"
	45	#include "channels.h"
	46	#include "bufaux.h"
	47	#include "ssh2.h"
	48	#include "auth.h"
	49	#include "session.h"
	50	#include "dispatch.h"
	51	#include "auth.h"
	52	#include "key.h"
	53	#include "kex.h"
	54
	55	#include "dsa.h"
	56	#include "uidswap.h"
	57
	58	/* import */
	59	extern ServerOptions options;
	60	extern unsigned char *session_id2;
	61	extern int session_id2_len;
	62
	63	/* protocol */
	64
	65	void input_service_request(int type, int plen);
	66	void input_userauth_request(int type, int plen);
	67	void protocol_error(int type, int plen);
	68
	69	/* auth */
	70	int ssh2_auth_none(struct passwd *pw);
	71	int ssh2_auth_password(struct passwd *pw);
	72	int ssh2_auth_pubkey(struct passwd pw, unsigned char raw, unsigned int rlen);
	73
	74	/* helper */
	75	struct passwd* auth_set_user(char u, char s);
	76	int user_dsa_key_allowed(struct passwd pw, Key key);
	77
	78	typedef struct Authctxt Authctxt;
	79	struct Authctxt {
	80	char *user;
	81	char *service;
	82	struct passwd pw;
	83	int valid;
	84	};
	85	static Authctxt *authctxt = NULL;
	86	static int userauth_success = 0;
	87
	88	/*
	89	* loop until userauth_success == TRUE
	90	*/
	91
	92	void
	93	do_authentication2()
	94	{
3189621b	95	/* turn off skey/kerberos, not supported by SSH2 */
8cb940db	96	#ifdef SKEY
3189621b	97	options.skey_authentication = 0;
8cb940db	98	#endif
8cb940db	99	#ifdef KRB4
3189621b	100	options.kerberos_authentication = 0;
8cb940db	101	#endif
3189621b	102
a306f2dd	103	dispatch_init(&protocol_error);
	104	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
	105	dispatch_run(DISPATCH_BLOCK, &userauth_success);
	106	do_authenticated2();
	107	}
	108
	109	void
	110	protocol_error(int type, int plen)
	111	{
	112	log("auth: protocol error: type %d plen %d", type, plen);
	113	packet_start(SSH2_MSG_UNIMPLEMENTED);
	114	packet_put_int(0);
	115	packet_send();
	116	packet_write_wait();
	117	}
	118
	119	void
	120	input_service_request(int type, int plen)
	121	{
	122	unsigned int len;
	123	int accept = 0;
	124	char *service = packet_get_string(&len);
	125	packet_done();
	126
	127	if (strcmp(service, "ssh-userauth") == 0) {
	128	if (!userauth_success) {
	129	accept = 1;
	130	/* now we can handle user-auth requests */
	131	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
	132	}
	133	}
	134	/* XXX all other service requests are denied */
	135
	136	if (accept) {
	137	packet_start(SSH2_MSG_SERVICE_ACCEPT);
	138	packet_put_cstring(service);
	139	packet_send();
	140	packet_write_wait();
	141	} else {
	142	debug("bad service request %s", service);
	143	packet_disconnect("bad service request %s", service);
	144	}
	145	xfree(service);
	146	}
	147
	148	void
	149	input_userauth_request(int type, int plen)
	150	{
	151	static void (authlog) (const char fmt,...) = verbose;
	152	static int attempt = 0;
	153	unsigned int len, rlen;
	154	int authenticated = 0;
	155	char raw, user, service, method, *authmsg = NULL;
	156	struct passwd *pw;
c1ef8333	157	#ifdef WITH_AIXAUTHENTICATE
	158	extern char *aixloginmsg;
	159	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	160
	161	raw = packet_get_raw(&rlen);
	162	if (plen != rlen)
	163	fatal("plen != rlen");
	164	user = packet_get_string(&len);
	165	service = packet_get_string(&len);
	166	method = packet_get_string(&len);
c1ef8333	167	if (++attempt == AUTH_FAIL_MAX) {
	168	#ifdef WITH_AIXAUTHENTICATE
	169	loginfailed(user,get_canonical_hostname(),"ssh");
	170	#endif /* WITH_AIXAUTHENTICATE */
	171	packet_disconnect("too many failed userauth_requests");
	172	}
a306f2dd	173	debug("userauth-request for user %s service %s method %s", user, service, method);
	174
	175	/* XXX we only allow the ssh-connection service */
	176	pw = auth_set_user(user, service);
	177	if (pw && strcmp(service, "ssh-connection")==0) {
	178	if (strcmp(method, "none") == 0) {
	179	authenticated = ssh2_auth_none(pw);
	180	} else if (strcmp(method, "password") == 0) {
	181	authenticated = ssh2_auth_password(pw);
	182	} else if (strcmp(method, "publickey") == 0) {
	183	authenticated = ssh2_auth_pubkey(pw, raw, rlen);
	184	}
	185	}
	186	if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
	187	authenticated = 0;
	188	log("ROOT LOGIN REFUSED FROM %.200s",
	189	get_canonical_hostname());
	190	}
	191
	192	#ifdef USE_PAM
	193	if (authenticated && !do_pam_account(pw->pw_name, NULL))
	194	authenticated = 0;
	195	#endif /* USE_PAM */
	196
1d1ffb87	197	/* Raise logging level */
	198	if (authenticated == 1 \|\|
	199	attempt == AUTH_FAIL_LOG \|\|
	200	strcmp(method, "password") == 0)
	201	authlog = log;
	202
	203	/* Log before sending the reply */
a306f2dd	204	if (authenticated == 1) {
a306f2dd	205	authmsg = "Accepted";
1d1ffb87	206	} else if (authenticated == 0) {
	207	authmsg = "Failed";
	208	} else {
	209	authmsg = "Postponed";
	210	}
	211	authlog("%s %s for %.200s from %.200s port %d ssh2",
	212	authmsg,
	213	method,
	214	pw && pw->pw_uid == 0 ? "ROOT" : user,
	215	get_remote_ipaddr(),
	216	get_remote_port());
	217
	218	/* XXX todo: check if multiple auth methods are needed */
	219	if (authenticated == 1) {
c1ef8333	220	#ifdef WITH_AIXAUTHENTICATE
	221	/* We don't have a pty yet, so just label the line as "ssh" */
	222	if (loginsuccess(user,get_canonical_hostname(),"ssh",
	223	&aixloginmsg) < 0)
	224	aixloginmsg = NULL;
	225	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	226	/* turn off userauth */
	227	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
	228	packet_start(SSH2_MSG_USERAUTH_SUCCESS);
	229	packet_send();
	230	packet_write_wait();
	231	/* now we can break out */
	232	userauth_success = 1;
	233	} else if (authenticated == 0) {
a306f2dd	234	packet_start(SSH2_MSG_USERAUTH_FAILURE);
	235	packet_put_cstring("publickey,password"); /* XXX dynamic */
	236	packet_put_char(0); /* XXX partial success, unused */
	237	packet_send();
	238	packet_write_wait();
a306f2dd	239	}
a306f2dd	240
	241	xfree(service);
	242	xfree(user);
	243	xfree(method);
	244	}
	245
	246	int
	247	ssh2_auth_none(struct passwd *pw)
	248	{
	249	packet_done();
	250	#ifdef USE_PAM
	251	return auth_pam_password(pw, "");
	252	#else /* USE_PAM */
	253	return auth_password(pw, "");
	254	#endif /* USE_PAM */
	255	}
	256	int
	257	ssh2_auth_password(struct passwd *pw)
	258	{
	259	char *password;
	260	int authenticated = 0;
	261	int change;
	262	unsigned int len;
	263	change = packet_get_char();
	264	if (change)
	265	log("password change not supported");
	266	password = packet_get_string(&len);
	267	packet_done();
	268	if (options.password_authentication &&
	269	#ifdef USE_PAM
	270	auth_pam_password(pw, password) == 1)
	271	#else /* USE_PAM */
	272	auth_password(pw, password) == 1)
	273	#endif /* USE_PAM */
	274	authenticated = 1;
	275	memset(password, 0, len);
	276	xfree(password);
	277	return authenticated;
	278	}
	279	int
	280	ssh2_auth_pubkey(struct passwd pw, unsigned char raw, unsigned int rlen)
	281	{
	282	Buffer b;
	283	Key *key;
	284	char pkalg, pkblob, *sig;
	285	unsigned int alen, blen, slen;
	286	int have_sig;
	287	int authenticated = 0;
	288
1d1ffb87	289	if (options.dsa_authentication == 0) {
a306f2dd	290	debug("pubkey auth disabled");
	291	return 0;
	292	}
d0c832f3	293	if (datafellows & SSH_BUG_PUBKEYAUTH) {
	294	log("bug compatibility with ssh-2.0.13 pubkey not implemented");
	295	return 0;
	296	}
a306f2dd	297	have_sig = packet_get_char();
	298	pkalg = packet_get_string(&alen);
	299	if (strcmp(pkalg, KEX_DSS) != 0) {
	300	xfree(pkalg);
	301	log("bad pkalg %s", pkalg); /XXX/
	302	return 0;
	303	}
	304	pkblob = packet_get_string(&blen);
	305	key = dsa_key_from_blob(pkblob, blen);
	306	if (key != NULL) {
	307	if (have_sig) {
	308	sig = packet_get_string(&slen);
	309	packet_done();
	310	buffer_init(&b);
	311	buffer_append(&b, session_id2, session_id2_len);
	312	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
	313	if (slen + 4 > rlen)
	314	fatal("bad rlen/slen");
	315	buffer_append(&b, raw, rlen - slen - 4);
	316	#ifdef DEBUG_DSS
	317	buffer_dump(&b);
	318	#endif
	319	/* test for correct signature */
	320	if (user_dsa_key_allowed(pw, key) &&
	321	dsa_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
	322	authenticated = 1;
	323	buffer_clear(&b);
	324	xfree(sig);
	325	} else {
	326	packet_done();
	327	debug("test key...");
	328	/* test whether pkalg/pkblob are acceptable */
	329	/* XXX fake reply and always send PK_OK ? */
1d1ffb87	330	/*
	331	* XXX this allows testing whether a user is allowed
	332	* to login: if you happen to have a valid pubkey this
	333	* message is sent. the message is NEVER sent at all
	334	* if a user is not allowed to login. is this an
	335	* issue? -markus
	336	*/
a306f2dd	337	if (user_dsa_key_allowed(pw, key)) {
	338	packet_start(SSH2_MSG_USERAUTH_PK_OK);
	339	packet_put_string(pkalg, alen);
	340	packet_put_string(pkblob, blen);
	341	packet_send();
	342	packet_write_wait();
	343	authenticated = -1;
	344	}
	345	}
	346	key_free(key);
	347	}
	348	xfree(pkalg);
	349	xfree(pkblob);
	350	return authenticated;
	351	}
	352
	353	/* set and get current user */
	354
	355	struct passwd*
	356	auth_get_user(void)
	357	{
	358	return (authctxt != NULL && authctxt->valid) ? &authctxt->pw : NULL;
	359	}
	360
	361	struct passwd*
	362	auth_set_user(char u, char s)
	363	{
	364	struct passwd pw, copy;
	365
	366	if (authctxt == NULL) {
	367	authctxt = xmalloc(sizeof(*authctxt));
	368	authctxt->valid = 0;
	369	authctxt->user = xstrdup(u);
	370	authctxt->service = xstrdup(s);
	371	setproctitle("%s", u);
	372	pw = getpwnam(u);
	373	if (!pw \|\| !allowed_user(pw)) {
	374	log("auth_set_user: illegal user %s", u);
	375	return NULL;
	376	}
	377	#ifdef USE_PAM
	378	start_pam(pw);
	379	#endif
	380	copy = &authctxt->pw;
	381	memset(copy, 0, sizeof(*copy));
	382	copy->pw_name = xstrdup(pw->pw_name);
	383	copy->pw_passwd = xstrdup(pw->pw_passwd);
	384	copy->pw_uid = pw->pw_uid;
	385	copy->pw_gid = pw->pw_gid;
	386	copy->pw_dir = xstrdup(pw->pw_dir);
	387	copy->pw_shell = xstrdup(pw->pw_shell);
	388	authctxt->valid = 1;
	389	} else {
	390	if (strcmp(u, authctxt->user) != 0 \|\|
	391	strcmp(s, authctxt->service) != 0) {
	392	log("auth_set_user: missmatch: (%s,%s)!=(%s,%s)",
	393	u, s, authctxt->user, authctxt->service);
	394	return NULL;
	395	}
	396	}
	397	return auth_get_user();
	398	}
	399
	400	/* return 1 if user allows given key */
401	int
402	user_dsa_key_allowed(struct passwd pw, Key key)
403	{
404	char line[8192], file[1024];
405	int found_key = 0;
406	unsigned int bits = -1;
407	FILE *f;
408	unsigned long linenum = 0;
409	struct stat st;
410	Key *found;
411
412	/* Temporarily use the user's uid. */
413	temporarily_use_uid(pw->pw_uid);
414
415	/* The authorized keys. */
416	snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
417	SSH_USER_PERMITTED_KEYS2);
418
419	/* Fail quietly if file does not exist */
420	if (stat(file, &st) < 0) {
421	/* Restore the privileged uid. */
422	restore_uid();
423	return 0;
424	}
425	/* Open the file containing the authorized keys. */
426	f = fopen(file, "r");
427	if (!f) {
428	/* Restore the privileged uid. */
429	restore_uid();
430	return 0;
431	}
432	if (options.strict_modes) {
433	int fail = 0;
434	char buf[1024];
435	/* Check open file in order to avoid open/stat races */
436	if (fstat(fileno(f), &st) < 0 \|\|
437	(st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
438	(st.st_mode & 022) != 0) {
439	snprintf(buf, sizeof buf, "DSA authentication refused for %.100s: "
440	"bad ownership or modes for '%s'.", pw->pw_name, file);
441	fail = 1;
442	} else {
443	/* Check path to SSH_USER_PERMITTED_KEYS */
444	int i;
445	static const char *check[] = {
446	"", SSH_USER_DIR, NULL
447	};
448	for (i = 0; check[i]; i++) {
449	snprintf(line, sizeof line, "%.500s/%.100s",
450	pw->pw_dir, check[i]);
451	if (stat(line, &st) < 0 \|\|
452	(st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
453	(st.st_mode & 022) != 0) {
454	snprintf(buf, sizeof buf,
455	"DSA authentication refused for %.100s: "
456	"bad ownership or modes for '%s'.",
457	pw->pw_name, line);
458	fail = 1;
459	break;
460	}
461	}
462	}
463	if (fail) {
464	log(buf);
465	fclose(f);
466	restore_uid();
467	return 0;
468	}
469	}
470	found_key = 0;
471	found = key_new(KEY_DSA);
472
473	while (fgets(line, sizeof(line), f)) {
474	char *cp;
475	linenum++;
476	/* Skip leading whitespace, empty and comment lines. */
477	for (cp = line; cp == ' ' \|\| cp == '\t'; cp++)
478	;
479	if (!cp \|\| cp == '\n' \|\| *cp == '#')
480	continue;
481	bits = key_read(found, &cp);
482	if (bits == 0)
483	continue;
484	if (key_equal(found, key)) {
485	found_key = 1;
486	debug("matching key found: file %s, line %ld",
487	file, linenum);
488	break;
489	}
490	}
491	restore_uid();
492	fclose(f);
493	key_free(found);
494	return found_key;
495	}