[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 1.10 2000/06/18 04:05:02 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"
#include "auth-options.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, char *service);

/* 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;
	int authenticated = 0;
	char *user, *service, *method, *authmsg = NULL;
	struct passwd *pw;
#ifdef WITH_AIXAUTHENTICATE
	extern char *aixloginmsg;
#endif /* WITH_AIXAUTHENTICATE */

	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, service);
		}
	}
	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, char *service)
{
	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;
	}
	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);

			/* reconstruct packet */
			buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
			buffer_put_cstring(&b, pw->pw_name);
			buffer_put_cstring(&b,
			    datafellows & SSH_BUG_PUBKEYAUTH ?
			    "ssh-userauth" :
			    service);
			buffer_put_cstring(&b, "publickey");
			buffer_put_char(&b, have_sig);
			buffer_put_cstring(&b, KEX_DSS);
			buffer_put_string(&b, pkblob, blen);
#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, *options = NULL;
		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) {
			/* no key?  check if there are options for this key */
			int quoted = 0;
			options = cp;
			for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
				if (*cp == '\\' && cp[1] == '"')
					cp++;	/* Skip both */
				else if (*cp == '"')
					quoted = !quoted;
			}
			/* Skip remaining whitespace. */
			for (; *cp == ' ' || *cp == '\t'; cp++)
				;
			bits = key_read(found, &cp);
			if (bits == 0) {
				/* still no key?  advance to next line*/
				continue;
			}
		}
		if (key_equal(found, key) &&
		    auth_parse_options(pw, options, linenum) == 1) {
			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"
38c295d6	30	RCSID("$OpenBSD: auth2.c,v 1.10 2000/06/18 04:05:02 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"
38c295d6	57	#include "auth-options.h"
a306f2dd	58
	59	/* import */
	60	extern ServerOptions options;
	61	extern unsigned char *session_id2;
	62	extern int session_id2_len;
	63
	64	/* protocol */
	65
	66	void input_service_request(int type, int plen);
	67	void input_userauth_request(int type, int plen);
	68	void protocol_error(int type, int plen);
	69
	70	/* auth */
	71	int ssh2_auth_none(struct passwd *pw);
	72	int ssh2_auth_password(struct passwd *pw);
38c295d6	73	int ssh2_auth_pubkey(struct passwd pw, char service);
a306f2dd	74
	75	/* helper */
	76	struct passwd* auth_set_user(char u, char s);
	77	int user_dsa_key_allowed(struct passwd pw, Key key);
	78
	79	typedef struct Authctxt Authctxt;
	80	struct Authctxt {
	81	char *user;
	82	char *service;
	83	struct passwd pw;
	84	int valid;
	85	};
	86	static Authctxt *authctxt = NULL;
	87	static int userauth_success = 0;
	88
	89	/*
	90	* loop until userauth_success == TRUE
	91	*/
	92
	93	void
	94	do_authentication2()
	95	{
3189621b	96	/* turn off skey/kerberos, not supported by SSH2 */
8cb940db	97	#ifdef SKEY
3189621b	98	options.skey_authentication = 0;
8cb940db	99	#endif
8cb940db	100	#ifdef KRB4
3189621b	101	options.kerberos_authentication = 0;
8cb940db	102	#endif
3189621b	103
a306f2dd	104	dispatch_init(&protocol_error);
	105	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
	106	dispatch_run(DISPATCH_BLOCK, &userauth_success);
	107	do_authenticated2();
	108	}
	109
	110	void
	111	protocol_error(int type, int plen)
	112	{
	113	log("auth: protocol error: type %d plen %d", type, plen);
	114	packet_start(SSH2_MSG_UNIMPLEMENTED);
	115	packet_put_int(0);
	116	packet_send();
	117	packet_write_wait();
	118	}
	119
	120	void
	121	input_service_request(int type, int plen)
	122	{
	123	unsigned int len;
	124	int accept = 0;
	125	char *service = packet_get_string(&len);
	126	packet_done();
	127
	128	if (strcmp(service, "ssh-userauth") == 0) {
	129	if (!userauth_success) {
	130	accept = 1;
	131	/* now we can handle user-auth requests */
	132	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
	133	}
	134	}
	135	/* XXX all other service requests are denied */
	136
	137	if (accept) {
	138	packet_start(SSH2_MSG_SERVICE_ACCEPT);
	139	packet_put_cstring(service);
	140	packet_send();
	141	packet_write_wait();
	142	} else {
	143	debug("bad service request %s", service);
	144	packet_disconnect("bad service request %s", service);
	145	}
	146	xfree(service);
	147	}
	148
	149	void
	150	input_userauth_request(int type, int plen)
	151	{
	152	static void (authlog) (const char fmt,...) = verbose;
	153	static int attempt = 0;
38c295d6	154	unsigned int len;
a306f2dd	155	int authenticated = 0;
38c295d6	156	char user, service, method, authmsg = NULL;
a306f2dd	157	struct passwd *pw;
c1ef8333	158	#ifdef WITH_AIXAUTHENTICATE
	159	extern char *aixloginmsg;
	160	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	161
a306f2dd	162	user = packet_get_string(&len);
	163	service = packet_get_string(&len);
	164	method = packet_get_string(&len);
c1ef8333	165	if (++attempt == AUTH_FAIL_MAX) {
	166	#ifdef WITH_AIXAUTHENTICATE
	167	loginfailed(user,get_canonical_hostname(),"ssh");
	168	#endif /* WITH_AIXAUTHENTICATE */
	169	packet_disconnect("too many failed userauth_requests");
	170	}
a306f2dd	171	debug("userauth-request for user %s service %s method %s", user, service, method);
	172
	173	/* XXX we only allow the ssh-connection service */
	174	pw = auth_set_user(user, service);
	175	if (pw && strcmp(service, "ssh-connection")==0) {
	176	if (strcmp(method, "none") == 0) {
	177	authenticated = ssh2_auth_none(pw);
	178	} else if (strcmp(method, "password") == 0) {
	179	authenticated = ssh2_auth_password(pw);
	180	} else if (strcmp(method, "publickey") == 0) {
38c295d6	181	authenticated = ssh2_auth_pubkey(pw, service);
a306f2dd	182	}
	183	}
	184	if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
	185	authenticated = 0;
	186	log("ROOT LOGIN REFUSED FROM %.200s",
	187	get_canonical_hostname());
	188	}
	189
	190	#ifdef USE_PAM
	191	if (authenticated && !do_pam_account(pw->pw_name, NULL))
	192	authenticated = 0;
	193	#endif /* USE_PAM */
	194
1d1ffb87	195	/* Raise logging level */
	196	if (authenticated == 1 \|\|
	197	attempt == AUTH_FAIL_LOG \|\|
	198	strcmp(method, "password") == 0)
	199	authlog = log;
	200
	201	/* Log before sending the reply */
a306f2dd	202	if (authenticated == 1) {
a306f2dd	203	authmsg = "Accepted";
1d1ffb87	204	} else if (authenticated == 0) {
	205	authmsg = "Failed";
	206	} else {
	207	authmsg = "Postponed";
	208	}
	209	authlog("%s %s for %.200s from %.200s port %d ssh2",
	210	authmsg,
	211	method,
	212	pw && pw->pw_uid == 0 ? "ROOT" : user,
	213	get_remote_ipaddr(),
	214	get_remote_port());
	215
	216	/* XXX todo: check if multiple auth methods are needed */
	217	if (authenticated == 1) {
c1ef8333	218	#ifdef WITH_AIXAUTHENTICATE
	219	/* We don't have a pty yet, so just label the line as "ssh" */
	220	if (loginsuccess(user,get_canonical_hostname(),"ssh",
	221	&aixloginmsg) < 0)
	222	aixloginmsg = NULL;
	223	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	224	/* turn off userauth */
	225	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
	226	packet_start(SSH2_MSG_USERAUTH_SUCCESS);
	227	packet_send();
	228	packet_write_wait();
	229	/* now we can break out */
	230	userauth_success = 1;
	231	} else if (authenticated == 0) {
a306f2dd	232	packet_start(SSH2_MSG_USERAUTH_FAILURE);
	233	packet_put_cstring("publickey,password"); /* XXX dynamic */
	234	packet_put_char(0); /* XXX partial success, unused */
	235	packet_send();
	236	packet_write_wait();
a306f2dd	237	}
a306f2dd	238
	239	xfree(service);
	240	xfree(user);
	241	xfree(method);
	242	}
	243
	244	int
	245	ssh2_auth_none(struct passwd *pw)
	246	{
	247	packet_done();
	248	#ifdef USE_PAM
	249	return auth_pam_password(pw, "");
	250	#else /* USE_PAM */
	251	return auth_password(pw, "");
	252	#endif /* USE_PAM */
	253	}
	254	int
	255	ssh2_auth_password(struct passwd *pw)
	256	{
	257	char *password;
	258	int authenticated = 0;
	259	int change;
	260	unsigned int len;
	261	change = packet_get_char();
	262	if (change)
	263	log("password change not supported");
	264	password = packet_get_string(&len);
	265	packet_done();
	266	if (options.password_authentication &&
	267	#ifdef USE_PAM
	268	auth_pam_password(pw, password) == 1)
	269	#else /* USE_PAM */
	270	auth_password(pw, password) == 1)
	271	#endif /* USE_PAM */
	272	authenticated = 1;
	273	memset(password, 0, len);
	274	xfree(password);
	275	return authenticated;
	276	}
	277	int
38c295d6	278	ssh2_auth_pubkey(struct passwd pw, char service)
a306f2dd	279	{
	280	Buffer b;
	281	Key *key;
	282	char pkalg, pkblob, *sig;
	283	unsigned int alen, blen, slen;
	284	int have_sig;
	285	int authenticated = 0;
	286
1d1ffb87	287	if (options.dsa_authentication == 0) {
a306f2dd	288	debug("pubkey auth disabled");
	289	return 0;
	290	}
	291	have_sig = packet_get_char();
	292	pkalg = packet_get_string(&alen);
	293	if (strcmp(pkalg, KEX_DSS) != 0) {
	294	xfree(pkalg);
	295	log("bad pkalg %s", pkalg); /XXX/
	296	return 0;
	297	}
	298	pkblob = packet_get_string(&blen);
	299	key = dsa_key_from_blob(pkblob, blen);
	300	if (key != NULL) {
	301	if (have_sig) {
	302	sig = packet_get_string(&slen);
	303	packet_done();
	304	buffer_init(&b);
	305	buffer_append(&b, session_id2, session_id2_len);
38c295d6	306
38c295d6	307	/* reconstruct packet */
a306f2dd	308	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
38c295d6	309	buffer_put_cstring(&b, pw->pw_name);
	310	buffer_put_cstring(&b,
	311	datafellows & SSH_BUG_PUBKEYAUTH ?
	312	"ssh-userauth" :
	313	service);
	314	buffer_put_cstring(&b, "publickey");
	315	buffer_put_char(&b, have_sig);
	316	buffer_put_cstring(&b, KEX_DSS);
	317	buffer_put_string(&b, pkblob, blen);
a306f2dd	318	#ifdef DEBUG_DSS
	319	buffer_dump(&b);
	320	#endif
	321	/* test for correct signature */
	322	if (user_dsa_key_allowed(pw, key) &&
	323	dsa_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
	324	authenticated = 1;
	325	buffer_clear(&b);
	326	xfree(sig);
	327	} else {
	328	packet_done();
	329	debug("test key...");
	330	/* test whether pkalg/pkblob are acceptable */
	331	/* XXX fake reply and always send PK_OK ? */
1d1ffb87	332	/*
	333	* XXX this allows testing whether a user is allowed
	334	* to login: if you happen to have a valid pubkey this
	335	* message is sent. the message is NEVER sent at all
	336	* if a user is not allowed to login. is this an
	337	* issue? -markus
	338	*/
a306f2dd	339	if (user_dsa_key_allowed(pw, key)) {
	340	packet_start(SSH2_MSG_USERAUTH_PK_OK);
	341	packet_put_string(pkalg, alen);
	342	packet_put_string(pkblob, blen);
	343	packet_send();
	344	packet_write_wait();
	345	authenticated = -1;
	346	}
	347	}
	348	key_free(key);
	349	}
	350	xfree(pkalg);
	351	xfree(pkblob);
	352	return authenticated;
	353	}
	354
	355	/* set and get current user */
	356
	357	struct passwd*
	358	auth_get_user(void)
	359	{
	360	return (authctxt != NULL && authctxt->valid) ? &authctxt->pw : NULL;
	361	}
	362
	363	struct passwd*
	364	auth_set_user(char u, char s)
	365	{
	366	struct passwd pw, copy;
	367
	368	if (authctxt == NULL) {
	369	authctxt = xmalloc(sizeof(*authctxt));
	370	authctxt->valid = 0;
	371	authctxt->user = xstrdup(u);
	372	authctxt->service = xstrdup(s);
	373	setproctitle("%s", u);
	374	pw = getpwnam(u);
	375	if (!pw \|\| !allowed_user(pw)) {
	376	log("auth_set_user: illegal user %s", u);
	377	return NULL;
	378	}
	379	#ifdef USE_PAM
	380	start_pam(pw);
	381	#endif
	382	copy = &authctxt->pw;
	383	memset(copy, 0, sizeof(*copy));
	384	copy->pw_name = xstrdup(pw->pw_name);
	385	copy->pw_passwd = xstrdup(pw->pw_passwd);
	386	copy->pw_uid = pw->pw_uid;
	387	copy->pw_gid = pw->pw_gid;
	388	copy->pw_dir = xstrdup(pw->pw_dir);
	389	copy->pw_shell = xstrdup(pw->pw_shell);
	390	authctxt->valid = 1;
	391	} else {
	392	if (strcmp(u, authctxt->user) != 0 \|\|
	393	strcmp(s, authctxt->service) != 0) {
	394	log("auth_set_user: missmatch: (%s,%s)!=(%s,%s)",
	395	u, s, authctxt->user, authctxt->service);
	396	return NULL;
	397	}
	398	}
	399	return auth_get_user();
	400	}
	401
	402	/* return 1 if user allows given key */
403	int
404	user_dsa_key_allowed(struct passwd pw, Key key)
405	{
406	char line[8192], file[1024];
407	int found_key = 0;
408	unsigned int bits = -1;
409	FILE *f;
410	unsigned long linenum = 0;
411	struct stat st;
412	Key *found;
413
414	/* Temporarily use the user's uid. */
415	temporarily_use_uid(pw->pw_uid);
416
417	/* The authorized keys. */
418	snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
419	SSH_USER_PERMITTED_KEYS2);
420
421	/* Fail quietly if file does not exist */
422	if (stat(file, &st) < 0) {
423	/* Restore the privileged uid. */
424	restore_uid();
425	return 0;
426	}
427	/* Open the file containing the authorized keys. */
428	f = fopen(file, "r");
429	if (!f) {
430	/* Restore the privileged uid. */
431	restore_uid();
432	return 0;
433	}
434	if (options.strict_modes) {
435	int fail = 0;
436	char buf[1024];
437	/* Check open file in order to avoid open/stat races */
438	if (fstat(fileno(f), &st) < 0 \|\|
439	(st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
440	(st.st_mode & 022) != 0) {
441	snprintf(buf, sizeof buf, "DSA authentication refused for %.100s: "
442	"bad ownership or modes for '%s'.", pw->pw_name, file);
443	fail = 1;
444	} else {
445	/* Check path to SSH_USER_PERMITTED_KEYS */
446	int i;
447	static const char *check[] = {
448	"", SSH_USER_DIR, NULL
449	};
450	for (i = 0; check[i]; i++) {
451	snprintf(line, sizeof line, "%.500s/%.100s",
452	pw->pw_dir, check[i]);
453	if (stat(line, &st) < 0 \|\|
454	(st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
455	(st.st_mode & 022) != 0) {
456	snprintf(buf, sizeof buf,
457	"DSA authentication refused for %.100s: "
458	"bad ownership or modes for '%s'.",
459	pw->pw_name, line);
460	fail = 1;
461	break;
462	}
463	}
464	}
465	if (fail) {
466	log(buf);
467	fclose(f);
468	restore_uid();
469	return 0;
470	}
471	}
472	found_key = 0;
473	found = key_new(KEY_DSA);
474
475	while (fgets(line, sizeof(line), f)) {
38c295d6	476	char cp, options = NULL;
a306f2dd	477	linenum++;
	478	/* Skip leading whitespace, empty and comment lines. */
	479	for (cp = line; cp == ' ' \|\| cp == '\t'; cp++)
	480	;
	481	if (!cp \|\| cp == '\n' \|\| *cp == '#')
	482	continue;
38c295d6	483
a306f2dd	484	bits = key_read(found, &cp);
38c295d6	485	if (bits == 0) {
	486	/* no key? check if there are options for this key */
	487	int quoted = 0;
	488	options = cp;
	489	for (; cp && (quoted \|\| (cp != ' ' && *cp != '\t')); cp++) {
	490	if (*cp == '\\' && cp[1] == '"')
	491	cp++; /* Skip both */
	492	else if (*cp == '"')
	493	quoted = !quoted;
	494	}
	495	/* Skip remaining whitespace. */
	496	for (; cp == ' ' \|\| cp == '\t'; cp++)
	497	;
	498	bits = key_read(found, &cp);
	499	if (bits == 0) {
	500	/* still no key? advance to next line*/
	501	continue;
	502	}
	503	}
	504	if (key_equal(found, key) &&
	505	auth_parse_options(pw, options, linenum) == 1) {
a306f2dd	506	found_key = 1;
	507	debug("matching key found: file %s, line %ld",
	508	file, linenum);
	509	break;
	510	}
	511	}
	512	restore_uid();
	513	fclose(f);
	514	key_free(found);
	515	return found_key;
	516	}