[openssh.git] / auth1.c

/*
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * 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".
 */

#include "includes.h"
RCSID("$OpenBSD: auth1.c,v 1.7 2000/11/10 01:04:40 markus Exp $");

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

#include "xmalloc.h"
#include "rsa.h"
#include "ssh.h"
#include "packet.h"
#include "buffer.h"
#include "mpaux.h"
#include "servconf.h"
#include "compat.h"
#include "auth.h"
#include "session.h"

/* import */
extern ServerOptions options;
extern char *forced_command;

#ifdef WITH_AIXAUTHENTICATE
extern char *aixloginmsg;
#endif /* WITH_AIXAUTHENTICATE */
#ifdef HAVE_OSF_SIA
extern int saved_argc;
extern char **saved_argv;
#endif /* HAVE_OSF_SIA */

/*
 * convert ssh auth msg type into description
 */
char *
get_authname(int type)
{
	static char buf[1024];
	switch (type) {
	case SSH_CMSG_AUTH_PASSWORD:
		return "password";
	case SSH_CMSG_AUTH_RSA:
		return "rsa";
	case SSH_CMSG_AUTH_RHOSTS_RSA:
		return "rhosts-rsa";
	case SSH_CMSG_AUTH_RHOSTS:
		return "rhosts";
#ifdef KRB4
	case SSH_CMSG_AUTH_KERBEROS:
		return "kerberos";
#endif
#ifdef SKEY
	case SSH_CMSG_AUTH_TIS_RESPONSE:
		return "s/key";
#endif
	}
	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	return buf;
}

/*
 * read packets and try to authenticate local user 'luser'.
 * return if authentication is successfull. not that pw == NULL
 * if the user does not exists or is not allowed to login.
 * each auth method has to 'fake' authentication for nonexisting
 * users.
 */
void
do_authloop(struct passwd * pw, char *luser)
{
	int authenticated = 0;
	int attempt = 0;
	unsigned int bits;
	RSA *client_host_key;
	BIGNUM *n;
	char *client_user, *password;
	char user[1024];
	unsigned int dlen;
	int plen, nlen, elen;
	unsigned int ulen;
	int type = 0;
	void (*authlog) (const char *fmt,...) = verbose;

	/* Indicate that authentication is needed. */
	packet_start(SSH_SMSG_FAILURE);
	packet_send();
	packet_write_wait();

	client_user = NULL;

	for (attempt = 1;; attempt++) {
		/* default to fail */
		authenticated = 0;

		strlcpy(user, "", sizeof user);

		/* Get a packet from the client. */
		type = packet_read(&plen);

		/* Process the packet. */
		switch (type) {
#ifdef AFS
		case SSH_CMSG_HAVE_KERBEROS_TGT:
			if (!options.kerberos_tgt_passing) {
				verbose("Kerberos tgt passing disabled.");
				break;
			} else {
				/* Accept Kerberos tgt. */
				char *tgt = packet_get_string(&dlen);
				packet_integrity_check(plen, 4 + dlen, type);
				if (!auth_kerberos_tgt(pw, tgt))
					verbose("Kerberos tgt REFUSED for %.100s", luser);
				xfree(tgt);
			}
			continue;

		case SSH_CMSG_HAVE_AFS_TOKEN:
			if (!options.afs_token_passing || !k_hasafs()) {
				verbose("AFS token passing disabled.");
				break;
			} else {
				/* Accept AFS token. */
				char *token_string = packet_get_string(&dlen);
				packet_integrity_check(plen, 4 + dlen, type);
				if (!auth_afs_token(pw, token_string))
					verbose("AFS token REFUSED for %.100s", luser);
				xfree(token_string);
			}
			continue;
#endif /* AFS */
#ifdef KRB4
		case SSH_CMSG_AUTH_KERBEROS:
			if (!options.kerberos_authentication) {
				/* packet_get_all(); */
				verbose("Kerberos authentication disabled.");
				break;
			} else {
				/* Try Kerberos v4 authentication. */
				KTEXT_ST auth;
				char *tkt_user = NULL;
				char *kdata = packet_get_string((unsigned int *) &auth.length);
				packet_integrity_check(plen, 4 + auth.length, type);

				if (auth.length < MAX_KTXT_LEN)
					memcpy(auth.dat, kdata, auth.length);
				xfree(kdata);

				if (pw != NULL) {
					authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
					if (authenticated) {
						snprintf(user, sizeof user, " tktuser %s", tkt_user);
						xfree(tkt_user);
					}
				}
			}
			break;
#endif /* KRB4 */

		case SSH_CMSG_AUTH_RHOSTS:
			if (!options.rhosts_authentication) {
				verbose("Rhosts authentication disabled.");
				break;
			}
			/*
			 * Get client user name.  Note that we just have to
			 * trust the client; this is one reason why rhosts
			 * authentication is insecure. (Another is
			 * IP-spoofing on a local network.)
			 */
			client_user = packet_get_string(&ulen);
			packet_integrity_check(plen, 4 + ulen, type);

			/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
			authenticated = auth_rhosts(pw, client_user);

			snprintf(user, sizeof user, " ruser %s", client_user);
			break;

		case SSH_CMSG_AUTH_RHOSTS_RSA:
			if (!options.rhosts_rsa_authentication) {
				verbose("Rhosts with RSA authentication disabled.");
				break;
			}
			/*
			 * Get client user name.  Note that we just have to
			 * trust the client; root on the client machine can
			 * claim to be any user.
			 */
			client_user = packet_get_string(&ulen);

			/* Get the client host key. */
			client_host_key = RSA_new();
			if (client_host_key == NULL)
				fatal("RSA_new failed");
			client_host_key->e = BN_new();
			client_host_key->n = BN_new();
			if (client_host_key->e == NULL || client_host_key->n == NULL)
				fatal("BN_new failed");
			bits = packet_get_int();
			packet_get_bignum(client_host_key->e, &elen);
			packet_get_bignum(client_host_key->n, &nlen);

			if (bits != BN_num_bits(client_host_key->n))
				verbose("Warning: keysize mismatch for client_host_key: "
				    "actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
			packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);

			authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
			RSA_free(client_host_key);

			snprintf(user, sizeof user, " ruser %s", client_user);
			break;

		case SSH_CMSG_AUTH_RSA:
			if (!options.rsa_authentication) {
				verbose("RSA authentication disabled.");
				break;
			}
			/* RSA authentication requested. */
			n = BN_new();
			packet_get_bignum(n, &nlen);
			packet_integrity_check(plen, nlen, type);
			authenticated = auth_rsa(pw, n);
			BN_clear_free(n);
			break;

		case SSH_CMSG_AUTH_PASSWORD:
			if (!options.password_authentication) {
				verbose("Password authentication disabled.");
				break;
			}
			/*
			 * Read user password.  It is in plain text, but was
			 * transmitted over the encrypted channel so it is
			 * not visible to an outside observer.
			 */
			password = packet_get_string(&dlen);
			packet_integrity_check(plen, 4 + dlen, type);

#ifdef USE_PAM
			/* Do PAM auth with password */
			authenticated = auth_pam_password(pw, password);
#elif defined(HAVE_OSF_SIA)
			/* Do SIA auth with password */
			if (sia_validate_user(NULL, saved_argc, saved_argv, 
				get_canonical_hostname(), pw->pw_name, NULL, 0, 
				NULL, password) == SIASUCCESS) {
				authenticated = 1;
			}
#else /* !USE_PAM && !HAVE_OSF_SIA */
 			/* Try authentication with the password. */
			authenticated = auth_password(pw, password);
#endif /* USE_PAM */

			memset(password, 0, strlen(password));
			xfree(password);
			break;

#ifdef SKEY
		case SSH_CMSG_AUTH_TIS:
			debug("rcvd SSH_CMSG_AUTH_TIS");
			if (options.skey_authentication == 1) {
				char *skeyinfo = NULL;
				if (pw != NULL)
					skeyinfo = skey_keyinfo(pw->pw_name);
				if (skeyinfo == NULL) {
					debug("generating fake skeyinfo for %.100s.", luser);
					skeyinfo = skey_fake_keyinfo(luser);
				}
				if (skeyinfo != NULL) {
					/* we send our s/key- in tis-challenge messages */
					debug("sending challenge '%s'", skeyinfo);
					packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
					packet_put_cstring(skeyinfo);
					packet_send();
					packet_write_wait();
					continue;
				}
			}
			break;
		case SSH_CMSG_AUTH_TIS_RESPONSE:
			debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
			if (options.skey_authentication == 1) {
				char *response = packet_get_string(&dlen);
				debug("skey response == '%s'", response);
				packet_integrity_check(plen, 4 + dlen, type);
				authenticated = (pw != NULL &&
				    skey_haskey(pw->pw_name) == 0 &&
				    skey_passcheck(pw->pw_name, response) != -1);
				xfree(response);
			}
			break;
#else
		case SSH_CMSG_AUTH_TIS:
			/* TIS Authentication is unsupported */
			log("TIS authentication unsupported.");
			break;
#endif

		default:
			/*
			 * Any unknown messages will be ignored (and failure
			 * returned) during authentication.
			 */
			log("Unknown message during authentication: type %d", type);
			break;
		}
		if (authenticated && pw == NULL)
			fatal("internal error: authenticated for pw == NULL");

#ifdef HAVE_CYGWIN
		if (authenticated && 
		    !check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) {
			packet_disconnect("Authentication rejected for uid %d.",
			(int)pw->pw_uid);
			authenticated = 0;
		}
#endif

		/*
		 * Check if the user is logging in as root and root logins
		 * are disallowed.
		 * Note that root login is allowed for forced commands.
		 */
		if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
			if (forced_command) {
				log("Root login accepted for forced command.");
			} else {
				authenticated = 0;
				log("ROOT LOGIN REFUSED FROM %.200s",
				    get_canonical_hostname());
			}
		}

		/* Raise logging level */
		if (authenticated ||
		    attempt == AUTH_FAIL_LOG ||
		    type == SSH_CMSG_AUTH_PASSWORD)
			authlog = log;

		authlog("%s %s for %s%.100s from %.200s port %d%s",
			authenticated ? "Accepted" : "Failed",
			get_authname(type),
			pw ? "" : "illegal user ",
			pw && pw->pw_uid == 0 ? "ROOT" : luser,
			get_remote_ipaddr(),
			get_remote_port(),
			user);

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

		if (client_user != NULL) {
			xfree(client_user);
			client_user = NULL;
		}

		if (authenticated)
			return;

		if (attempt > AUTH_FAIL_MAX) {
#ifdef WITH_AIXAUTHENTICATE 
			loginfailed(user,get_canonical_hostname(),"ssh");
#endif /* WITH_AIXAUTHENTICATE */
			packet_disconnect(AUTH_FAIL_MSG, luser);
		}

		/* Send a message indicating that the authentication attempt failed. */
		packet_start(SSH_SMSG_FAILURE);
		packet_send();
		packet_write_wait();
	}
}

/*
 * Performs authentication of an incoming connection.  Session key has already
 * been exchanged and encryption is enabled.
 */
void
do_authentication()
{
	struct passwd *pw, pwcopy;
	int plen;
	unsigned int ulen;
	char *user;

	/* Get the name of the user that we wish to log in as. */
	packet_read_expect(&plen, SSH_CMSG_USER);

	/* Get the user name. */
	user = packet_get_string(&ulen);
	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);

	setproctitle("%s", user);

#ifdef AFS
	/* If machine has AFS, set process authentication group. */
	if (k_hasafs()) {
		k_setpag();
		k_unlog();
	}
#endif /* AFS */

	/* Verify that the user is a valid user. */
	pw = getpwnam(user);
	if (pw && allowed_user(pw)) {
		/* Take a copy of the returned structure. */
		memset(&pwcopy, 0, sizeof(pwcopy));
		pwcopy.pw_name = xstrdup(pw->pw_name);
		pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
		pwcopy.pw_uid = pw->pw_uid;
		pwcopy.pw_gid = pw->pw_gid;
#ifdef HAVE_PW_CLASS_IN_PASSWD
		pwcopy.pw_class = xstrdup(pw->pw_class);
#endif
		pwcopy.pw_dir = xstrdup(pw->pw_dir);
		pwcopy.pw_shell = xstrdup(pw->pw_shell);
		pw = &pwcopy;
	} else {
		pw = NULL;
	}

#ifdef USE_PAM
	if (pw)
		start_pam(pw);
#endif

	/*
	 * If we are not running as root, the user must have the same uid as
	 * the server. (Unless you are running Windows)
	 */
#ifndef HAVE_CYGWIN
	if (getuid() != 0 && pw && pw->pw_uid != getuid())
		packet_disconnect("Cannot change user when server not running as root.");
#endif

	debug("Attempting authentication for %s%.100s.", pw ? "" : "illegal user ", user);

	/* If the user has no password, accept authentication immediately. */
	if (options.password_authentication &&
#ifdef KRB4
	    (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif /* KRB4 */
#ifdef USE_PAM
	    auth_pam_password(pw, "")) {
#elif defined(HAVE_OSF_SIA)
	    (sia_validate_user(NULL, saved_argc, saved_argv, 
	    get_canonical_hostname(), pw->pw_name, NULL, 0, 
		 NULL, "") == SIASUCCESS)) {
#else /* !HAVE_OSF_SIA && !USE_PAM */
 	    auth_password(pw, "")) {
#endif /* USE_PAM */
		/* Authentication with empty password succeeded. */
		log("Login for user %s from %.100s, accepted without authentication.",
		    user, get_remote_ipaddr());
	} else {
		/* Loop until the user has been authenticated or the
		   connection is closed, do_authloop() returns only if
		   authentication is successfull */
		do_authloop(pw, user);
	}
	if (pw == NULL)
		fatal("internal error, authentication successfull for user '%.100s'", user);

	/* The user has been authenticated and accepted. */
	packet_start(SSH_SMSG_SUCCESS);
	packet_send();
	packet_write_wait();

#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 */

	/* Perform session preparation. */
	do_authenticated(pw);
}
Commit	Line	Data
a306f2dd	1	/*
	2	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	3	* All rights reserved
bcbf86ec	4	*
	5	* As far as I am concerned, the code I have written for this software
	6	* can be used freely for any purpose. Any derived versions of this
	7	* software must be clearly marked as such, and if the derived work is
	8	* incompatible with the protocol description in the RFC file, it must be
	9	* called by a name other than "ssh" or "Secure Shell".
a306f2dd	10	*/
	11
	12	#include "includes.h"
fa08c86b	13	RCSID("$OpenBSD: auth1.c,v 1.7 2000/11/10 01:04:40 markus Exp $");
94ec8c6b	14
	15	#ifdef HAVE_OSF_SIA
	16	# include <sia.h>
	17	# include <siad.h>
	18	#endif
a306f2dd	19
	20	#include "xmalloc.h"
	21	#include "rsa.h"
	22	#include "ssh.h"
	23	#include "packet.h"
	24	#include "buffer.h"
a306f2dd	25	#include "mpaux.h"
	26	#include "servconf.h"
	27	#include "compat.h"
	28	#include "auth.h"
	29	#include "session.h"
	30
	31	/* import */
	32	extern ServerOptions options;
	33	extern char *forced_command;
94ec8c6b	34
	35	#ifdef WITH_AIXAUTHENTICATE
	36	extern char *aixloginmsg;
	37	#endif /* WITH_AIXAUTHENTICATE */
b3f162ba	38	#ifdef HAVE_OSF_SIA
	39	extern int saved_argc;
	40	extern char **saved_argv;
	41	#endif /* HAVE_OSF_SIA */
a306f2dd	42
	43	/*
	44	* convert ssh auth msg type into description
	45	*/
	46	char *
	47	get_authname(int type)
	48	{
	49	static char buf[1024];
	50	switch (type) {
	51	case SSH_CMSG_AUTH_PASSWORD:
	52	return "password";
	53	case SSH_CMSG_AUTH_RSA:
	54	return "rsa";
	55	case SSH_CMSG_AUTH_RHOSTS_RSA:
	56	return "rhosts-rsa";
	57	case SSH_CMSG_AUTH_RHOSTS:
	58	return "rhosts";
	59	#ifdef KRB4
	60	case SSH_CMSG_AUTH_KERBEROS:
	61	return "kerberos";
	62	#endif
	63	#ifdef SKEY
	64	case SSH_CMSG_AUTH_TIS_RESPONSE:
	65	return "s/key";
	66	#endif
	67	}
	68	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	69	return buf;
	70	}
	71
	72	/*
94ec8c6b	73	* read packets and try to authenticate local user 'luser'.
	74	* return if authentication is successfull. not that pw == NULL
	75	* if the user does not exists or is not allowed to login.
	76	* each auth method has to 'fake' authentication for nonexisting
	77	* users.
a306f2dd	78	*/
a306f2dd	79	void
94ec8c6b	80	do_authloop(struct passwd * pw, char *luser)
a306f2dd	81	{
94ec8c6b	82	int authenticated = 0;
a306f2dd	83	int attempt = 0;
	84	unsigned int bits;
	85	RSA *client_host_key;
	86	BIGNUM *n;
94ec8c6b	87	char client_user, password;
a306f2dd	88	char user[1024];
	89	unsigned int dlen;
	90	int plen, nlen, elen;
	91	unsigned int ulen;
	92	int type = 0;
	93	void (authlog) (const char fmt,...) = verbose;
	94
	95	/* Indicate that authentication is needed. */
	96	packet_start(SSH_SMSG_FAILURE);
	97	packet_send();
	98	packet_write_wait();
	99
94ec8c6b	100	client_user = NULL;
94ec8c6b	101
a306f2dd	102	for (attempt = 1;; attempt++) {
94ec8c6b	103	/* default to fail */
	104	authenticated = 0;
	105
a306f2dd	106	strlcpy(user, "", sizeof user);
	107
	108	/* Get a packet from the client. */
	109	type = packet_read(&plen);
	110
	111	/* Process the packet. */
	112	switch (type) {
	113	#ifdef AFS
	114	case SSH_CMSG_HAVE_KERBEROS_TGT:
	115	if (!options.kerberos_tgt_passing) {
a306f2dd	116	verbose("Kerberos tgt passing disabled.");
	117	break;
	118	} else {
	119	/* Accept Kerberos tgt. */
	120	char *tgt = packet_get_string(&dlen);
	121	packet_integrity_check(plen, 4 + dlen, type);
	122	if (!auth_kerberos_tgt(pw, tgt))
94ec8c6b	123	verbose("Kerberos tgt REFUSED for %.100s", luser);
a306f2dd	124	xfree(tgt);
	125	}
	126	continue;
	127
	128	case SSH_CMSG_HAVE_AFS_TOKEN:
	129	if (!options.afs_token_passing \|\| !k_hasafs()) {
a306f2dd	130	verbose("AFS token passing disabled.");
	131	break;
	132	} else {
	133	/* Accept AFS token. */
	134	char *token_string = packet_get_string(&dlen);
	135	packet_integrity_check(plen, 4 + dlen, type);
	136	if (!auth_afs_token(pw, token_string))
94ec8c6b	137	verbose("AFS token REFUSED for %.100s", luser);
a306f2dd	138	xfree(token_string);
	139	}
	140	continue;
	141	#endif /* AFS */
	142	#ifdef KRB4
	143	case SSH_CMSG_AUTH_KERBEROS:
	144	if (!options.kerberos_authentication) {
	145	/* packet_get_all(); */
	146	verbose("Kerberos authentication disabled.");
	147	break;
	148	} else {
	149	/* Try Kerberos v4 authentication. */
	150	KTEXT_ST auth;
	151	char *tkt_user = NULL;
	152	char kdata = packet_get_string((unsigned int ) &auth.length);
	153	packet_integrity_check(plen, 4 + auth.length, type);
	154
	155	if (auth.length < MAX_KTXT_LEN)
	156	memcpy(auth.dat, kdata, auth.length);
	157	xfree(kdata);
	158
94ec8c6b	159	if (pw != NULL) {
	160	authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
	161	if (authenticated) {
	162	snprintf(user, sizeof user, " tktuser %s", tkt_user);
	163	xfree(tkt_user);
	164	}
a306f2dd	165	}
	166	}
	167	break;
	168	#endif /* KRB4 */
	169
	170	case SSH_CMSG_AUTH_RHOSTS:
	171	if (!options.rhosts_authentication) {
	172	verbose("Rhosts authentication disabled.");
	173	break;
	174	}
	175	/*
	176	* Get client user name. Note that we just have to
	177	* trust the client; this is one reason why rhosts
	178	* authentication is insecure. (Another is
	179	* IP-spoofing on a local network.)
	180	*/
	181	client_user = packet_get_string(&ulen);
	182	packet_integrity_check(plen, 4 + ulen, type);
	183
94ec8c6b	184	/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
a306f2dd	185	authenticated = auth_rhosts(pw, client_user);
	186
	187	snprintf(user, sizeof user, " ruser %s", client_user);
	188	break;
	189
	190	case SSH_CMSG_AUTH_RHOSTS_RSA:
	191	if (!options.rhosts_rsa_authentication) {
	192	verbose("Rhosts with RSA authentication disabled.");
	193	break;
	194	}
	195	/*
	196	* Get client user name. Note that we just have to
	197	* trust the client; root on the client machine can
	198	* claim to be any user.
	199	*/
	200	client_user = packet_get_string(&ulen);
	201
	202	/* Get the client host key. */
	203	client_host_key = RSA_new();
	204	if (client_host_key == NULL)
	205	fatal("RSA_new failed");
	206	client_host_key->e = BN_new();
	207	client_host_key->n = BN_new();
	208	if (client_host_key->e == NULL \|\| client_host_key->n == NULL)
	209	fatal("BN_new failed");
	210	bits = packet_get_int();
	211	packet_get_bignum(client_host_key->e, &elen);
	212	packet_get_bignum(client_host_key->n, &nlen);
	213
	214	if (bits != BN_num_bits(client_host_key->n))
94ec8c6b	215	verbose("Warning: keysize mismatch for client_host_key: "
0b242b12	216	"actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
a306f2dd	217	packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
	218
	219	authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
	220	RSA_free(client_host_key);
	221
	222	snprintf(user, sizeof user, " ruser %s", client_user);
	223	break;
	224
	225	case SSH_CMSG_AUTH_RSA:
	226	if (!options.rsa_authentication) {
	227	verbose("RSA authentication disabled.");
	228	break;
	229	}
	230	/* RSA authentication requested. */
	231	n = BN_new();
	232	packet_get_bignum(n, &nlen);
	233	packet_integrity_check(plen, nlen, type);
	234	authenticated = auth_rsa(pw, n);
	235	BN_clear_free(n);
	236	break;
	237
	238	case SSH_CMSG_AUTH_PASSWORD:
	239	if (!options.password_authentication) {
	240	verbose("Password authentication disabled.");
	241	break;
	242	}
	243	/*
	244	* Read user password. It is in plain text, but was
	245	* transmitted over the encrypted channel so it is
	246	* not visible to an outside observer.
	247	*/
	248	password = packet_get_string(&dlen);
	249	packet_integrity_check(plen, 4 + dlen, type);
	250
	251	#ifdef USE_PAM
	252	/* Do PAM auth with password */
	253	authenticated = auth_pam_password(pw, password);
4d33e531	254	#elif defined(HAVE_OSF_SIA)
4d33e531	255	/* Do SIA auth with password */
4d33e531	256	if (sia_validate_user(NULL, saved_argc, saved_argv,
	257	get_canonical_hostname(), pw->pw_name, NULL, 0,
	258	NULL, password) == SIASUCCESS) {
	259	authenticated = 1;
	260	}
	261	#else /* !USE_PAM && !HAVE_OSF_SIA */
94ec8c6b	262	/* Try authentication with the password. */
a306f2dd	263	authenticated = auth_password(pw, password);
	264	#endif /* USE_PAM */
	265
	266	memset(password, 0, strlen(password));
	267	xfree(password);
	268	break;
	269
	270	#ifdef SKEY
	271	case SSH_CMSG_AUTH_TIS:
	272	debug("rcvd SSH_CMSG_AUTH_TIS");
	273	if (options.skey_authentication == 1) {
94ec8c6b	274	char *skeyinfo = NULL;
94ec8c6b	275	if (pw != NULL)
3e366738	276	skeyinfo = skey_keyinfo(pw->pw_name);
a306f2dd	277	if (skeyinfo == NULL) {
94ec8c6b	278	debug("generating fake skeyinfo for %.100s.", luser);
94ec8c6b	279	skeyinfo = skey_fake_keyinfo(luser);
a306f2dd	280	}
	281	if (skeyinfo != NULL) {
	282	/* we send our s/key- in tis-challenge messages */
	283	debug("sending challenge '%s'", skeyinfo);
	284	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
94ec8c6b	285	packet_put_cstring(skeyinfo);
a306f2dd	286	packet_send();
	287	packet_write_wait();
	288	continue;
	289	}
	290	}
	291	break;
	292	case SSH_CMSG_AUTH_TIS_RESPONSE:
	293	debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
	294	if (options.skey_authentication == 1) {
	295	char *response = packet_get_string(&dlen);
	296	debug("skey response == '%s'", response);
	297	packet_integrity_check(plen, 4 + dlen, type);
94ec8c6b	298	authenticated = (pw != NULL &&
	299	skey_haskey(pw->pw_name) == 0 &&
	300	skey_passcheck(pw->pw_name, response) != -1);
a306f2dd	301	xfree(response);
	302	}
	303	break;
	304	#else
	305	case SSH_CMSG_AUTH_TIS:
	306	/* TIS Authentication is unsupported */
	307	log("TIS authentication unsupported.");
	308	break;
	309	#endif
	310
	311	default:
	312	/*
	313	* Any unknown messages will be ignored (and failure
	314	* returned) during authentication.
	315	*/
	316	log("Unknown message during authentication: type %d", type);
	317	break;
	318	}
94ec8c6b	319	if (authenticated && pw == NULL)
94ec8c6b	320	fatal("internal error: authenticated for pw == NULL");
a306f2dd	321
3c62e7eb	322	#ifdef HAVE_CYGWIN
94ec8c6b	323	if (authenticated &&
9cd45ea4	324	!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) {
3c62e7eb	325	packet_disconnect("Authentication rejected for uid %d.",
94ec8c6b	326	(int)pw->pw_uid);
3c62e7eb	327	authenticated = 0;
	328	}
	329	#endif
	330
a306f2dd	331	/*
	332	* Check if the user is logging in as root and root logins
	333	* are disallowed.
	334	* Note that root login is allowed for forced commands.
	335	*/
94ec8c6b	336	if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) {
a306f2dd	337	if (forced_command) {
	338	log("Root login accepted for forced command.");
	339	} else {
	340	authenticated = 0;
	341	log("ROOT LOGIN REFUSED FROM %.200s",
	342	get_canonical_hostname());
	343	}
	344	}
	345
	346	/* Raise logging level */
	347	if (authenticated \|\|
	348	attempt == AUTH_FAIL_LOG \|\|
	349	type == SSH_CMSG_AUTH_PASSWORD)
	350	authlog = log;
	351
94ec8c6b	352	authlog("%s %s for %s%.100s from %.200s port %d%s",
a306f2dd	353	authenticated ? "Accepted" : "Failed",
a306f2dd	354	get_authname(type),
94ec8c6b	355	pw ? "" : "illegal user ",
94ec8c6b	356	pw && pw->pw_uid == 0 ? "ROOT" : luser,
a306f2dd	357	get_remote_ipaddr(),
	358	get_remote_port(),
	359	user);
	360
	361	#ifdef USE_PAM
94ec8c6b	362	if (authenticated && !do_pam_account(pw->pw_name, client_user))
	363	authenticated = 0;
	364	#endif
a306f2dd	365
	366	if (client_user != NULL) {
	367	xfree(client_user);
	368	client_user = NULL;
	369	}
	370
94ec8c6b	371	if (authenticated)
	372	return;
	373
c1ef8333	374	if (attempt > AUTH_FAIL_MAX) {
c1ef8333	375	#ifdef WITH_AIXAUTHENTICATE
94ec8c6b	376	loginfailed(user,get_canonical_hostname(),"ssh");
c1ef8333	377	#endif /* WITH_AIXAUTHENTICATE */
94ec8c6b	378	packet_disconnect(AUTH_FAIL_MSG, luser);
c1ef8333	379	}
a306f2dd	380
	381	/* Send a message indicating that the authentication attempt failed. */
	382	packet_start(SSH_SMSG_FAILURE);
	383	packet_send();
	384	packet_write_wait();
	385	}
	386	}
	387
	388	/*
	389	* Performs authentication of an incoming connection. Session key has already
	390	* been exchanged and encryption is enabled.
	391	*/
	392	void
	393	do_authentication()
	394	{
	395	struct passwd *pw, pwcopy;
	396	int plen;
	397	unsigned int ulen;
	398	char *user;
a306f2dd	399
	400	/* Get the name of the user that we wish to log in as. */
	401	packet_read_expect(&plen, SSH_CMSG_USER);
	402
	403	/* Get the user name. */
	404	user = packet_get_string(&ulen);
	405	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
	406
	407	setproctitle("%s", user);
	408
	409	#ifdef AFS
	410	/* If machine has AFS, set process authentication group. */
	411	if (k_hasafs()) {
	412	k_setpag();
	413	k_unlog();
	414	}
	415	#endif /* AFS */
	416
	417	/* Verify that the user is a valid user. */
	418	pw = getpwnam(user);
94ec8c6b	419	if (pw && allowed_user(pw)) {
	420	/* Take a copy of the returned structure. */
	421	memset(&pwcopy, 0, sizeof(pwcopy));
	422	pwcopy.pw_name = xstrdup(pw->pw_name);
	423	pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
	424	pwcopy.pw_uid = pw->pw_uid;
	425	pwcopy.pw_gid = pw->pw_gid;
2e73a022	426	#ifdef HAVE_PW_CLASS_IN_PASSWD
94ec8c6b	427	pwcopy.pw_class = xstrdup(pw->pw_class);
2e73a022	428	#endif
94ec8c6b	429	pwcopy.pw_dir = xstrdup(pw->pw_dir);
	430	pwcopy.pw_shell = xstrdup(pw->pw_shell);
	431	pw = &pwcopy;
	432	} else {
	433	pw = NULL;
	434	}
a306f2dd	435
a306f2dd	436	#ifdef USE_PAM
94ec8c6b	437	if (pw)
94ec8c6b	438	start_pam(pw);
a306f2dd	439	#endif
	440
	441	/*
	442	* If we are not running as root, the user must have the same uid as
94ec8c6b	443	* the server. (Unless you are running Windows)
a306f2dd	444	*/
94ec8c6b	445	#ifndef HAVE_CYGWIN
94ec8c6b	446	if (getuid() != 0 && pw && pw->pw_uid != getuid())
a306f2dd	447	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	448	#endif
a306f2dd	449
94ec8c6b	450	debug("Attempting authentication for %s%.100s.", pw ? "" : "illegal user ", user);
a306f2dd	451
	452	/* If the user has no password, accept authentication immediately. */
	453	if (options.password_authentication &&
	454	#ifdef KRB4
	455	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
	456	#endif /* KRB4 */
	457	#ifdef USE_PAM
	458	auth_pam_password(pw, "")) {
388e9f9f	459	#elif defined(HAVE_OSF_SIA)
388e9f9f	460	(sia_validate_user(NULL, saved_argc, saved_argv,
94ec8c6b	461	get_canonical_hostname(), pw->pw_name, NULL, 0,
94ec8c6b	462	NULL, "") == SIASUCCESS)) {
388e9f9f	463	#else /* !HAVE_OSF_SIA && !USE_PAM */
94ec8c6b	464	auth_password(pw, "")) {
a306f2dd	465	#endif /* USE_PAM */
	466	/* Authentication with empty password succeeded. */
	467	log("Login for user %s from %.100s, accepted without authentication.",
94ec8c6b	468	user, get_remote_ipaddr());
a306f2dd	469	} else {
	470	/* Loop until the user has been authenticated or the
	471	connection is closed, do_authloop() returns only if
	472	authentication is successfull */
94ec8c6b	473	do_authloop(pw, user);
a306f2dd	474	}
94ec8c6b	475	if (pw == NULL)
94ec8c6b	476	fatal("internal error, authentication successfull for user '%.100s'", user);
a306f2dd	477
a306f2dd	478	/* The user has been authenticated and accepted. */
94ec8c6b	479	packet_start(SSH_SMSG_SUCCESS);
	480	packet_send();
	481	packet_write_wait();
	482
a306f2dd	483	#ifdef WITH_AIXAUTHENTICATE
c1ef8333	484	/* We don't have a pty yet, so just label the line as "ssh" */
	485	if (loginsuccess(user,get_canonical_hostname(),"ssh",&aixloginmsg) < 0)
	486	aixloginmsg = NULL;
a306f2dd	487	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	488
	489	/* Perform session preparation. */
	490	do_authenticated(pw);
	491	}