[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 1.13 2000/08/20 18:42:40 millert 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"

#ifdef HAVE_OSF_SIA
# include <sia.h>
# include <siad.h>
#endif

/* 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)
{
#ifdef HAVE_OSF_SIA
	extern int saved_argc;
	extern char **saved_argv;
#endif

	packet_done();

#ifdef USE_PAM
	return auth_pam_password(pw, "");
#elif defined(HAVE_OSF_SIA)
	return(sia_validate_user(NULL, saved_argc, saved_argv, 
		get_canonical_hostname(), pw->pw_name, NULL, 0, NULL, 
		"") == SIASUCCESS);
#else /* !HAVE_OSF_SIA && !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;
#ifdef HAVE_OSF_SIA
	extern int saved_argc;
	extern char **saved_argv;
#endif
	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)
#elif defined(HAVE_OSF_SIA)
	    sia_validate_user(NULL, saved_argc, saved_argv, 
		 	get_canonical_hostname(), pw->pw_name, NULL, 0, 
			NULL, password) == SIASUCCESS)
#else /* !USE_PAM && !HAVE_OSF_SIA */
	    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);
			if (datafellows & SSH_COMPAT_SESSIONID_ENCODING) {
				buffer_put_string(&b, session_id2, session_id2_len);
			} else {
				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;
#ifdef HAVE_PW_CLASS_IN_PASSWD
		copy->pw_class = xstrdup(pw->pw_class);
#endif
		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) {
			fclose(f);
			log("%s",buf);
			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"
2e73a022	30	RCSID("$OpenBSD: auth2.c,v 1.13 2000/08/20 18:42:40 millert 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
4d33e531	59	#ifdef HAVE_OSF_SIA
	60	# include <sia.h>
	61	# include <siad.h>
	62	#endif
	63
a306f2dd	64	/* import */
	65	extern ServerOptions options;
	66	extern unsigned char *session_id2;
	67	extern int session_id2_len;
	68
	69	/* protocol */
	70
	71	void input_service_request(int type, int plen);
	72	void input_userauth_request(int type, int plen);
	73	void protocol_error(int type, int plen);
	74
	75	/* auth */
	76	int ssh2_auth_none(struct passwd *pw);
	77	int ssh2_auth_password(struct passwd *pw);
38c295d6	78	int ssh2_auth_pubkey(struct passwd pw, char service);
a306f2dd	79
	80	/* helper */
	81	struct passwd* auth_set_user(char u, char s);
	82	int user_dsa_key_allowed(struct passwd pw, Key key);
	83
	84	typedef struct Authctxt Authctxt;
	85	struct Authctxt {
	86	char *user;
	87	char *service;
	88	struct passwd pw;
	89	int valid;
	90	};
	91	static Authctxt *authctxt = NULL;
	92	static int userauth_success = 0;
	93
	94	/*
	95	* loop until userauth_success == TRUE
	96	*/
	97
	98	void
	99	do_authentication2()
	100	{
3189621b	101	/* turn off skey/kerberos, not supported by SSH2 */
8cb940db	102	#ifdef SKEY
3189621b	103	options.skey_authentication = 0;
8cb940db	104	#endif
8cb940db	105	#ifdef KRB4
3189621b	106	options.kerberos_authentication = 0;
8cb940db	107	#endif
3189621b	108
a306f2dd	109	dispatch_init(&protocol_error);
	110	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
	111	dispatch_run(DISPATCH_BLOCK, &userauth_success);
	112	do_authenticated2();
	113	}
	114
	115	void
	116	protocol_error(int type, int plen)
	117	{
	118	log("auth: protocol error: type %d plen %d", type, plen);
	119	packet_start(SSH2_MSG_UNIMPLEMENTED);
	120	packet_put_int(0);
	121	packet_send();
	122	packet_write_wait();
	123	}
	124
	125	void
	126	input_service_request(int type, int plen)
	127	{
	128	unsigned int len;
	129	int accept = 0;
	130	char *service = packet_get_string(&len);
	131	packet_done();
	132
	133	if (strcmp(service, "ssh-userauth") == 0) {
	134	if (!userauth_success) {
	135	accept = 1;
	136	/* now we can handle user-auth requests */
	137	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
	138	}
	139	}
	140	/* XXX all other service requests are denied */
	141
	142	if (accept) {
	143	packet_start(SSH2_MSG_SERVICE_ACCEPT);
	144	packet_put_cstring(service);
	145	packet_send();
	146	packet_write_wait();
	147	} else {
	148	debug("bad service request %s", service);
	149	packet_disconnect("bad service request %s", service);
	150	}
	151	xfree(service);
	152	}
	153
	154	void
	155	input_userauth_request(int type, int plen)
	156	{
	157	static void (authlog) (const char fmt,...) = verbose;
	158	static int attempt = 0;
38c295d6	159	unsigned int len;
a306f2dd	160	int authenticated = 0;
38c295d6	161	char user, service, method, authmsg = NULL;
a306f2dd	162	struct passwd *pw;
c1ef8333	163	#ifdef WITH_AIXAUTHENTICATE
	164	extern char *aixloginmsg;
	165	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	166
a306f2dd	167	user = packet_get_string(&len);
	168	service = packet_get_string(&len);
	169	method = packet_get_string(&len);
c1ef8333	170	if (++attempt == AUTH_FAIL_MAX) {
	171	#ifdef WITH_AIXAUTHENTICATE
	172	loginfailed(user,get_canonical_hostname(),"ssh");
	173	#endif /* WITH_AIXAUTHENTICATE */
	174	packet_disconnect("too many failed userauth_requests");
	175	}
a306f2dd	176	debug("userauth-request for user %s service %s method %s", user, service, method);
	177
	178	/* XXX we only allow the ssh-connection service */
	179	pw = auth_set_user(user, service);
	180	if (pw && strcmp(service, "ssh-connection")==0) {
	181	if (strcmp(method, "none") == 0) {
	182	authenticated = ssh2_auth_none(pw);
	183	} else if (strcmp(method, "password") == 0) {
	184	authenticated = ssh2_auth_password(pw);
	185	} else if (strcmp(method, "publickey") == 0) {
38c295d6	186	authenticated = ssh2_auth_pubkey(pw, service);
a306f2dd	187	}
	188	}
	189	if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
	190	authenticated = 0;
	191	log("ROOT LOGIN REFUSED FROM %.200s",
	192	get_canonical_hostname());
	193	}
	194
	195	#ifdef USE_PAM
	196	if (authenticated && !do_pam_account(pw->pw_name, NULL))
	197	authenticated = 0;
	198	#endif /* USE_PAM */
	199
1d1ffb87	200	/* Raise logging level */
	201	if (authenticated == 1 \|\|
	202	attempt == AUTH_FAIL_LOG \|\|
	203	strcmp(method, "password") == 0)
	204	authlog = log;
	205
	206	/* Log before sending the reply */
a306f2dd	207	if (authenticated == 1) {
a306f2dd	208	authmsg = "Accepted";
1d1ffb87	209	} else if (authenticated == 0) {
	210	authmsg = "Failed";
	211	} else {
	212	authmsg = "Postponed";
	213	}
	214	authlog("%s %s for %.200s from %.200s port %d ssh2",
	215	authmsg,
	216	method,
	217	pw && pw->pw_uid == 0 ? "ROOT" : user,
	218	get_remote_ipaddr(),
	219	get_remote_port());
	220
	221	/* XXX todo: check if multiple auth methods are needed */
	222	if (authenticated == 1) {
c1ef8333	223	#ifdef WITH_AIXAUTHENTICATE
	224	/* We don't have a pty yet, so just label the line as "ssh" */
	225	if (loginsuccess(user,get_canonical_hostname(),"ssh",
	226	&aixloginmsg) < 0)
	227	aixloginmsg = NULL;
	228	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	229	/* turn off userauth */
	230	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
	231	packet_start(SSH2_MSG_USERAUTH_SUCCESS);
	232	packet_send();
	233	packet_write_wait();
	234	/* now we can break out */
	235	userauth_success = 1;
	236	} else if (authenticated == 0) {
a306f2dd	237	packet_start(SSH2_MSG_USERAUTH_FAILURE);
	238	packet_put_cstring("publickey,password"); /* XXX dynamic */
	239	packet_put_char(0); /* XXX partial success, unused */
	240	packet_send();
	241	packet_write_wait();
a306f2dd	242	}
a306f2dd	243
	244	xfree(service);
	245	xfree(user);
	246	xfree(method);
	247	}
	248
	249	int
	250	ssh2_auth_none(struct passwd *pw)
	251	{
4d33e531	252	#ifdef HAVE_OSF_SIA
	253	extern int saved_argc;
	254	extern char **saved_argv;
	255	#endif
	256
a306f2dd	257	packet_done();
4d33e531	258
a306f2dd	259	#ifdef USE_PAM
a306f2dd	260	return auth_pam_password(pw, "");
4d33e531	261	#elif defined(HAVE_OSF_SIA)
	262	return(sia_validate_user(NULL, saved_argc, saved_argv,
	263	get_canonical_hostname(), pw->pw_name, NULL, 0, NULL,
	264	"") == SIASUCCESS);
	265	#else /* !HAVE_OSF_SIA && !USE_PAM */
a306f2dd	266	return auth_password(pw, "");
	267	#endif /* USE_PAM */
	268	}
	269	int
	270	ssh2_auth_password(struct passwd *pw)
	271	{
	272	char *password;
	273	int authenticated = 0;
	274	int change;
	275	unsigned int len;
4d33e531	276	#ifdef HAVE_OSF_SIA
	277	extern int saved_argc;
	278	extern char **saved_argv;
	279	#endif
a306f2dd	280	change = packet_get_char();
	281	if (change)
	282	log("password change not supported");
	283	password = packet_get_string(&len);
	284	packet_done();
	285	if (options.password_authentication &&
	286	#ifdef USE_PAM
	287	auth_pam_password(pw, password) == 1)
4d33e531	288	#elif defined(HAVE_OSF_SIA)
	289	sia_validate_user(NULL, saved_argc, saved_argv,
	290	get_canonical_hostname(), pw->pw_name, NULL, 0,
	291	NULL, password) == SIASUCCESS)
	292	#else /* !USE_PAM && !HAVE_OSF_SIA */
a306f2dd	293	auth_password(pw, password) == 1)
	294	#endif /* USE_PAM */
	295	authenticated = 1;
	296	memset(password, 0, len);
	297	xfree(password);
	298	return authenticated;
	299	}
	300	int
38c295d6	301	ssh2_auth_pubkey(struct passwd pw, char service)
a306f2dd	302	{
	303	Buffer b;
	304	Key *key;
	305	char pkalg, pkblob, *sig;
	306	unsigned int alen, blen, slen;
	307	int have_sig;
	308	int authenticated = 0;
	309
1d1ffb87	310	if (options.dsa_authentication == 0) {
a306f2dd	311	debug("pubkey auth disabled");
	312	return 0;
	313	}
	314	have_sig = packet_get_char();
	315	pkalg = packet_get_string(&alen);
	316	if (strcmp(pkalg, KEX_DSS) != 0) {
	317	xfree(pkalg);
	318	log("bad pkalg %s", pkalg); /XXX/
	319	return 0;
	320	}
	321	pkblob = packet_get_string(&blen);
	322	key = dsa_key_from_blob(pkblob, blen);
	323	if (key != NULL) {
	324	if (have_sig) {
	325	sig = packet_get_string(&slen);
	326	packet_done();
	327	buffer_init(&b);
74fc9186	328	if (datafellows & SSH_COMPAT_SESSIONID_ENCODING) {
	329	buffer_put_string(&b, session_id2, session_id2_len);
	330	} else {
	331	buffer_append(&b, session_id2, session_id2_len);
	332	}
38c295d6	333	/* reconstruct packet */
a306f2dd	334	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
38c295d6	335	buffer_put_cstring(&b, pw->pw_name);
	336	buffer_put_cstring(&b,
	337	datafellows & SSH_BUG_PUBKEYAUTH ?
	338	"ssh-userauth" :
	339	service);
	340	buffer_put_cstring(&b, "publickey");
	341	buffer_put_char(&b, have_sig);
	342	buffer_put_cstring(&b, KEX_DSS);
	343	buffer_put_string(&b, pkblob, blen);
a306f2dd	344	#ifdef DEBUG_DSS
	345	buffer_dump(&b);
	346	#endif
	347	/* test for correct signature */
	348	if (user_dsa_key_allowed(pw, key) &&
	349	dsa_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
	350	authenticated = 1;
	351	buffer_clear(&b);
	352	xfree(sig);
	353	} else {
	354	packet_done();
	355	debug("test key...");
	356	/* test whether pkalg/pkblob are acceptable */
	357	/* XXX fake reply and always send PK_OK ? */
1d1ffb87	358	/*
	359	* XXX this allows testing whether a user is allowed
	360	* to login: if you happen to have a valid pubkey this
	361	* message is sent. the message is NEVER sent at all
	362	* if a user is not allowed to login. is this an
	363	* issue? -markus
	364	*/
a306f2dd	365	if (user_dsa_key_allowed(pw, key)) {
	366	packet_start(SSH2_MSG_USERAUTH_PK_OK);
	367	packet_put_string(pkalg, alen);
	368	packet_put_string(pkblob, blen);
	369	packet_send();
	370	packet_write_wait();
	371	authenticated = -1;
	372	}
	373	}
	374	key_free(key);
	375	}
	376	xfree(pkalg);
	377	xfree(pkblob);
	378	return authenticated;
	379	}
	380
	381	/* set and get current user */
	382
	383	struct passwd*
	384	auth_get_user(void)
	385	{
	386	return (authctxt != NULL && authctxt->valid) ? &authctxt->pw : NULL;
	387	}
	388
	389	struct passwd*
	390	auth_set_user(char u, char s)
	391	{
	392	struct passwd pw, copy;
	393
	394	if (authctxt == NULL) {
	395	authctxt = xmalloc(sizeof(*authctxt));
	396	authctxt->valid = 0;
	397	authctxt->user = xstrdup(u);
	398	authctxt->service = xstrdup(s);
	399	setproctitle("%s", u);
	400	pw = getpwnam(u);
	401	if (!pw \|\| !allowed_user(pw)) {
	402	log("auth_set_user: illegal user %s", u);
	403	return NULL;
	404	}
	405	#ifdef USE_PAM
	406	start_pam(pw);
	407	#endif
	408	copy = &authctxt->pw;
	409	memset(copy, 0, sizeof(*copy));
	410	copy->pw_name = xstrdup(pw->pw_name);
	411	copy->pw_passwd = xstrdup(pw->pw_passwd);
	412	copy->pw_uid = pw->pw_uid;
	413	copy->pw_gid = pw->pw_gid;
2e73a022	414	#ifdef HAVE_PW_CLASS_IN_PASSWD
	415	copy->pw_class = xstrdup(pw->pw_class);
	416	#endif
a306f2dd	417	copy->pw_dir = xstrdup(pw->pw_dir);
	418	copy->pw_shell = xstrdup(pw->pw_shell);
	419	authctxt->valid = 1;
	420	} else {
	421	if (strcmp(u, authctxt->user) != 0 \|\|
	422	strcmp(s, authctxt->service) != 0) {
	423	log("auth_set_user: missmatch: (%s,%s)!=(%s,%s)",
	424	u, s, authctxt->user, authctxt->service);
	425	return NULL;
	426	}
	427	}
	428	return auth_get_user();
	429	}
	430
	431	/* return 1 if user allows given key */
	432	int
	433	user_dsa_key_allowed(struct passwd pw, Key key)
	434	{
	435	char line[8192], file[1024];
	436	int found_key = 0;
	437	unsigned int bits = -1;
	438	FILE *f;
	439	unsigned long linenum = 0;
	440	struct stat st;
	441	Key *found;
	442
	443	/* Temporarily use the user's uid. */
	444	temporarily_use_uid(pw->pw_uid);
	445
	446	/* The authorized keys. */
	447	snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
	448	SSH_USER_PERMITTED_KEYS2);
	449
	450	/* Fail quietly if file does not exist */
	451	if (stat(file, &st) < 0) {
	452	/* Restore the privileged uid. */
	453	restore_uid();
	454	return 0;
	455	}
	456	/* Open the file containing the authorized keys. */
	457	f = fopen(file, "r");
	458	if (!f) {
	459	/* Restore the privileged uid. */
	460	restore_uid();
	461	return 0;
	462	}
	463	if (options.strict_modes) {
	464	int fail = 0;
	465	char buf[1024];
	466	/* Check open file in order to avoid open/stat races */
	467	if (fstat(fileno(f), &st) < 0 \|\|
	468	(st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
	469	(st.st_mode & 022) != 0) {
	470	snprintf(buf, sizeof buf, "DSA authentication refused for %.100s: "
	471	"bad ownership or modes for '%s'.", pw->pw_name, file);
	472	fail = 1;
	473	} else {
	474	/* Check path to SSH_USER_PERMITTED_KEYS */
	475	int i;
	476	static const char *check[] = {
	477	"", SSH_USER_DIR, NULL
	478	};
	479	for (i = 0; check[i]; i++) {
	480	snprintf(line, sizeof line, "%.500s/%.100s",
481	pw->pw_dir, check[i]);
482	if (stat(line, &st) < 0 \|\|
483	(st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
484	(st.st_mode & 022) != 0) {
485	snprintf(buf, sizeof buf,
486	"DSA authentication refused for %.100s: "
487	"bad ownership or modes for '%s'.",
488	pw->pw_name, line);
489	fail = 1;
490	break;
491	}
492	}
493	}
494	if (fail) {
a306f2dd	495	fclose(f);
089fbbd2	496	log("%s",buf);
a306f2dd	497	restore_uid();
	498	return 0;
	499	}
	500	}
	501	found_key = 0;
	502	found = key_new(KEY_DSA);
	503
	504	while (fgets(line, sizeof(line), f)) {
38c295d6	505	char cp, options = NULL;
a306f2dd	506	linenum++;
	507	/* Skip leading whitespace, empty and comment lines. */
	508	for (cp = line; cp == ' ' \|\| cp == '\t'; cp++)
	509	;
	510	if (!cp \|\| cp == '\n' \|\| *cp == '#')
	511	continue;
38c295d6	512
a306f2dd	513	bits = key_read(found, &cp);
38c295d6	514	if (bits == 0) {
	515	/* no key? check if there are options for this key */
	516	int quoted = 0;
	517	options = cp;
	518	for (; cp && (quoted \|\| (cp != ' ' && *cp != '\t')); cp++) {
	519	if (*cp == '\\' && cp[1] == '"')
	520	cp++; /* Skip both */
	521	else if (*cp == '"')
	522	quoted = !quoted;
	523	}
	524	/* Skip remaining whitespace. */
	525	for (; cp == ' ' \|\| cp == '\t'; cp++)
	526	;
	527	bits = key_read(found, &cp);
	528	if (bits == 0) {
	529	/* still no key? advance to next line*/
	530	continue;
	531	}
	532	}
	533	if (key_equal(found, key) &&
	534	auth_parse_options(pw, options, linenum) == 1) {
a306f2dd	535	found_key = 1;
	536	debug("matching key found: file %s, line %ld",
	537	file, linenum);
	538	break;
	539	}
	540	}
	541	restore_uid();
	542	fclose(f);
	543	key_free(found);
	544	return found_key;
	545	}