[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 1.14 2001/01/22 23:06:39 markus Exp $");

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

#include "xmalloc.h"
#include "rsa.h"
#include "ssh1.h"
#include "packet.h"
#include "buffer.h"
#include "mpaux.h"
#include "log.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";
	case SSH_CMSG_AUTH_TIS:
	case SSH_CMSG_AUTH_TIS_RESPONSE:
		return "challenge-response";
#ifdef KRB4
	case SSH_CMSG_AUTH_KERBEROS:
		return "kerberos";
#endif
	}
	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	return buf;
}

/*
 * read packets, try to authenticate the user and
 * return only if authentication is successful
 */
void
do_authloop(Authctxt *authctxt)
{
	int authenticated = 0;
	u_int bits;
	RSA *client_host_key;
	BIGNUM *n;
	char *client_user, *password;
	char info[1024];
	u_int dlen;
	int plen, nlen, elen;
	u_int ulen;
	int type = 0;
	struct passwd *pw = authctxt->pw;

	debug("Attempting authentication for %s%.100s.",
	     authctxt->valid ? "" : "illegal user ", authctxt->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
#ifdef USE_PAM
	    auth_pam_password(pw, password)) {
#else
	    auth_password(pw, "")) {
#endif
		auth_log(authctxt, 1, "without authentication", "");
		return;
	}

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

	client_user = NULL;

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

		info[0] = '\0';

		/* 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", authctxt->user);
				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", authctxt->user);
				xfree(token_string);
			}
			continue;
#endif /* AFS */
#ifdef KRB4
		case SSH_CMSG_AUTH_KERBEROS:
			if (!options.kerberos_authentication) {
				verbose("Kerberos authentication disabled.");
				break;
			} else {
				/* Try Kerberos v4 authentication. */
				KTEXT_ST auth;
				char *tkt_user = NULL;
				char *kdata = packet_get_string((u_int *) &auth.length);
				packet_integrity_check(plen, 4 + auth.length, type);

				if (authctxt->valid) {
					if (auth.length < MAX_KTXT_LEN)
						memcpy(auth.dat, kdata, auth.length);
					authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
					if (authenticated) {
						snprintf(info, sizeof info,
						    " tktuser %.100s", tkt_user);
						xfree(tkt_user);
					}
				}
				xfree(kdata);
			}
			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(info, sizeof info, " ruser %.100s", 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(info, sizeof info, " ruser %.100s", 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(options.reverse_mapping_check), 
			    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;

		case SSH_CMSG_AUTH_TIS:
			debug("rcvd SSH_CMSG_AUTH_TIS");
			if (options.challenge_reponse_authentication == 1) {
				char *challenge = get_challenge(authctxt, authctxt->style);
				if (challenge != NULL) {
					debug("sending challenge '%s'", challenge);
					packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
					packet_put_cstring(challenge);
					packet_send();
					packet_write_wait();
					continue;
				}
			}
			break;
		case SSH_CMSG_AUTH_TIS_RESPONSE:
			debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
			if (options.challenge_reponse_authentication == 1) {
				char *response = packet_get_string(&dlen);
				debug("got response '%s'", response);
				packet_integrity_check(plen, 4 + dlen, type);
				authenticated = verify_response(authctxt, response);
				memset(response, 'r', dlen);
				xfree(response);
			}
			break;

		default:
			/*
			 * Any unknown messages will be ignored (and failure
			 * returned) during authentication.
			 */
			log("Unknown message during authentication: type %d", type);
			break;
		}
		if (!authctxt->valid && authenticated)
			fatal("INTERNAL ERROR: authenticated invalid user %s",
			    authctxt->user);

#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;
		}
#else
		/* Special handling for root */
		if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed())
			authenticated = 0;
#endif
#ifdef USE_PAM			
		if (authenticated && !do_pam_account(pw->pw_name, client_user))
			authenticated = 0;
#endif

		/* Log before sending the reply */
		auth_log(authctxt, authenticated, get_authname(type), info);

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

		if (authenticated)
			return;

		if (authctxt->failures++ > AUTH_FAIL_MAX) {
#ifdef WITH_AIXAUTHENTICATE 
			loginfailed(user, 
			    get_canonical_hostname(options.reverse_mapping_check), 
			    "ssh");
#endif /* WITH_AIXAUTHENTICATE */
			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
		}

		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()
{
	Authctxt *authctxt;
	struct passwd *pw;
	int plen;
	u_int ulen;
	char *user, *style = NULL;

	/* 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);

	if ((style = strchr(user, ':')) != NULL)
		*style++ = 0;

	authctxt = authctxt_new();
	authctxt->user = user;
	authctxt->style = style;

	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)) {
		authctxt->valid = 1;
		pw = pwcopy(pw);
	} else {
		debug("do_authentication: illegal user %s", user);
		pw = NULL;
	}
	authctxt->pw = pw;

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

	/*
	 * Loop until the user has been authenticated or the connection is
	 * closed, do_authloop() returns only if authentication is successful
	 */
	do_authloop(authctxt);

	/* 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(authctxt->user, 
	    get_canonical_hostname(options.reverse_mapping_check),
	    "ssh", &aixloginmsg) < 0)
		aixloginmsg = NULL;
#endif /* WITH_AIXAUTHENTICATE */

	xfree(authctxt->user);
	xfree(authctxt);

	/* 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"
d464095c	13	RCSID("$OpenBSD: auth1.c,v 1.14 2001/01/22 23:06:39 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"
42f11eb2	22	#include "ssh1.h"
a306f2dd	23	#include "packet.h"
a306f2dd	24	#include "buffer.h"
a306f2dd	25	#include "mpaux.h"
42f11eb2	26	#include "log.h"
a306f2dd	27	#include "servconf.h"
	28	#include "compat.h"
	29	#include "auth.h"
	30	#include "session.h"
	31
	32	/* import */
	33	extern ServerOptions options;
	34	extern char *forced_command;
94ec8c6b	35
	36	#ifdef WITH_AIXAUTHENTICATE
	37	extern char *aixloginmsg;
	38	#endif /* WITH_AIXAUTHENTICATE */
b3f162ba	39	#ifdef HAVE_OSF_SIA
	40	extern int saved_argc;
	41	extern char **saved_argv;
	42	#endif /* HAVE_OSF_SIA */
a306f2dd	43
	44	/*
	45	* convert ssh auth msg type into description
	46	*/
	47	char *
	48	get_authname(int type)
	49	{
	50	static char buf[1024];
	51	switch (type) {
	52	case SSH_CMSG_AUTH_PASSWORD:
	53	return "password";
	54	case SSH_CMSG_AUTH_RSA:
	55	return "rsa";
	56	case SSH_CMSG_AUTH_RHOSTS_RSA:
	57	return "rhosts-rsa";
	58	case SSH_CMSG_AUTH_RHOSTS:
	59	return "rhosts";
59c97189	60	case SSH_CMSG_AUTH_TIS:
	61	case SSH_CMSG_AUTH_TIS_RESPONSE:
	62	return "challenge-response";
a306f2dd	63	#ifdef KRB4
	64	case SSH_CMSG_AUTH_KERBEROS:
	65	return "kerberos";
a306f2dd	66	#endif
	67	}
	68	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	69	return buf;
	70	}
	71
	72	/*
59c97189	73	* read packets, try to authenticate the user and
59c97189	74	* return only if authentication is successful
a306f2dd	75	*/
a306f2dd	76	void
59c97189	77	do_authloop(Authctxt *authctxt)
a306f2dd	78	{
94ec8c6b	79	int authenticated = 0;
1e3b8b07	80	u_int bits;
a306f2dd	81	RSA *client_host_key;
a306f2dd	82	BIGNUM *n;
94ec8c6b	83	char client_user, password;
59c97189	84	char info[1024];
1e3b8b07	85	u_int dlen;
a306f2dd	86	int plen, nlen, elen;
1e3b8b07	87	u_int ulen;
a306f2dd	88	int type = 0;
59c97189	89	struct passwd *pw = authctxt->pw;
	90
	91	debug("Attempting authentication for %s%.100s.",
	92	authctxt->valid ? "" : "illegal user ", authctxt->user);
	93
	94	/* If the user has no password, accept authentication immediately. */
	95	if (options.password_authentication &&
	96	#ifdef KRB4
	97	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
	98	#endif
f4ebf0e8	99	#ifdef USE_PAM
59c97189	100	auth_pam_password(pw, password)) {
	101	#else
	102	auth_password(pw, "")) {
	103	#endif
	104	auth_log(authctxt, 1, "without authentication", "");
	105	return;
	106	}
a306f2dd	107
	108	/* Indicate that authentication is needed. */
	109	packet_start(SSH_SMSG_FAILURE);
	110	packet_send();
	111	packet_write_wait();
	112
94ec8c6b	113	client_user = NULL;
94ec8c6b	114
59c97189	115	for (;;) {
94ec8c6b	116	/* default to fail */
	117	authenticated = 0;
	118
59c97189	119	info[0] = '\0';
a306f2dd	120
	121	/* Get a packet from the client. */
	122	type = packet_read(&plen);
	123
	124	/* Process the packet. */
	125	switch (type) {
	126	#ifdef AFS
	127	case SSH_CMSG_HAVE_KERBEROS_TGT:
	128	if (!options.kerberos_tgt_passing) {
a306f2dd	129	verbose("Kerberos tgt passing disabled.");
	130	break;
	131	} else {
	132	/* Accept Kerberos tgt. */
	133	char *tgt = packet_get_string(&dlen);
	134	packet_integrity_check(plen, 4 + dlen, type);
	135	if (!auth_kerberos_tgt(pw, tgt))
59c97189	136	verbose("Kerberos tgt REFUSED for %.100s", authctxt->user);
a306f2dd	137	xfree(tgt);
	138	}
	139	continue;
	140
	141	case SSH_CMSG_HAVE_AFS_TOKEN:
	142	if (!options.afs_token_passing \|\| !k_hasafs()) {
a306f2dd	143	verbose("AFS token passing disabled.");
	144	break;
	145	} else {
	146	/* Accept AFS token. */
	147	char *token_string = packet_get_string(&dlen);
	148	packet_integrity_check(plen, 4 + dlen, type);
	149	if (!auth_afs_token(pw, token_string))
59c97189	150	verbose("AFS token REFUSED for %.100s", authctxt->user);
a306f2dd	151	xfree(token_string);
	152	}
	153	continue;
	154	#endif /* AFS */
	155	#ifdef KRB4
	156	case SSH_CMSG_AUTH_KERBEROS:
	157	if (!options.kerberos_authentication) {
a306f2dd	158	verbose("Kerberos authentication disabled.");
	159	break;
	160	} else {
	161	/* Try Kerberos v4 authentication. */
	162	KTEXT_ST auth;
	163	char *tkt_user = NULL;
1e3b8b07	164	char kdata = packet_get_string((u_int ) &auth.length);
a306f2dd	165	packet_integrity_check(plen, 4 + auth.length, type);
a306f2dd	166
59c97189	167	if (authctxt->valid) {
	168	if (auth.length < MAX_KTXT_LEN)
	169	memcpy(auth.dat, kdata, auth.length);
94ec8c6b	170	authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
94ec8c6b	171	if (authenticated) {
59c97189	172	snprintf(info, sizeof info,
59c97189	173	" tktuser %.100s", tkt_user);
94ec8c6b	174	xfree(tkt_user);
94ec8c6b	175	}
a306f2dd	176	}
59c97189	177	xfree(kdata);
a306f2dd	178	}
	179	break;
	180	#endif /* KRB4 */
	181
	182	case SSH_CMSG_AUTH_RHOSTS:
	183	if (!options.rhosts_authentication) {
	184	verbose("Rhosts authentication disabled.");
	185	break;
	186	}
	187	/*
	188	* Get client user name. Note that we just have to
	189	* trust the client; this is one reason why rhosts
	190	* authentication is insecure. (Another is
	191	* IP-spoofing on a local network.)
	192	*/
	193	client_user = packet_get_string(&ulen);
	194	packet_integrity_check(plen, 4 + ulen, type);
	195
94ec8c6b	196	/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
a306f2dd	197	authenticated = auth_rhosts(pw, client_user);
a306f2dd	198
59c97189	199	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	200	break;
	201
	202	case SSH_CMSG_AUTH_RHOSTS_RSA:
	203	if (!options.rhosts_rsa_authentication) {
	204	verbose("Rhosts with RSA authentication disabled.");
	205	break;
	206	}
	207	/*
	208	* Get client user name. Note that we just have to
	209	* trust the client; root on the client machine can
	210	* claim to be any user.
	211	*/
	212	client_user = packet_get_string(&ulen);
	213
	214	/* Get the client host key. */
	215	client_host_key = RSA_new();
	216	if (client_host_key == NULL)
	217	fatal("RSA_new failed");
	218	client_host_key->e = BN_new();
	219	client_host_key->n = BN_new();
	220	if (client_host_key->e == NULL \|\| client_host_key->n == NULL)
	221	fatal("BN_new failed");
	222	bits = packet_get_int();
	223	packet_get_bignum(client_host_key->e, &elen);
	224	packet_get_bignum(client_host_key->n, &nlen);
	225
	226	if (bits != BN_num_bits(client_host_key->n))
94ec8c6b	227	verbose("Warning: keysize mismatch for client_host_key: "
0b242b12	228	"actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
a306f2dd	229	packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
	230
	231	authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
	232	RSA_free(client_host_key);
	233
59c97189	234	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	235	break;
	236
	237	case SSH_CMSG_AUTH_RSA:
	238	if (!options.rsa_authentication) {
	239	verbose("RSA authentication disabled.");
	240	break;
	241	}
	242	/* RSA authentication requested. */
	243	n = BN_new();
	244	packet_get_bignum(n, &nlen);
	245	packet_integrity_check(plen, nlen, type);
	246	authenticated = auth_rsa(pw, n);
	247	BN_clear_free(n);
	248	break;
	249
	250	case SSH_CMSG_AUTH_PASSWORD:
	251	if (!options.password_authentication) {
	252	verbose("Password authentication disabled.");
	253	break;
	254	}
	255	/*
	256	* Read user password. It is in plain text, but was
	257	* transmitted over the encrypted channel so it is
	258	* not visible to an outside observer.
	259	*/
	260	password = packet_get_string(&dlen);
	261	packet_integrity_check(plen, 4 + dlen, type);
	262
	263	#ifdef USE_PAM
	264	/* Do PAM auth with password */
	265	authenticated = auth_pam_password(pw, password);
4d33e531	266	#elif defined(HAVE_OSF_SIA)
4d33e531	267	/* Do SIA auth with password */
4d33e531	268	if (sia_validate_user(NULL, saved_argc, saved_argv,
61e96248	269	get_canonical_hostname(options.reverse_mapping_check),
61e96248	270	pw->pw_name, NULL, 0, NULL, password) == SIASUCCESS) {
4d33e531	271	authenticated = 1;
	272	}
	273	#else /* !USE_PAM && !HAVE_OSF_SIA */
b4b5d644	274	/* Try authentication with the password. */
a306f2dd	275	authenticated = auth_password(pw, password);
	276	#endif /* USE_PAM */
	277
	278	memset(password, 0, strlen(password));
	279	xfree(password);
	280	break;
	281
a306f2dd	282	case SSH_CMSG_AUTH_TIS:
a306f2dd	283	debug("rcvd SSH_CMSG_AUTH_TIS");
d464095c	284	if (options.challenge_reponse_authentication == 1) {
59c97189	285	char *challenge = get_challenge(authctxt, authctxt->style);
	286	if (challenge != NULL) {
	287	debug("sending challenge '%s'", challenge);
a306f2dd	288	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
59c97189	289	packet_put_cstring(challenge);
a306f2dd	290	packet_send();
	291	packet_write_wait();
	292	continue;
	293	}
	294	}
	295	break;
	296	case SSH_CMSG_AUTH_TIS_RESPONSE:
	297	debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
d464095c	298	if (options.challenge_reponse_authentication == 1) {
a306f2dd	299	char *response = packet_get_string(&dlen);
59c97189	300	debug("got response '%s'", response);
a306f2dd	301	packet_integrity_check(plen, 4 + dlen, type);
59c97189	302	authenticated = verify_response(authctxt, response);
59c97189	303	memset(response, 'r', dlen);
a306f2dd	304	xfree(response);
	305	}
	306	break;
a306f2dd	307
	308	default:
	309	/*
	310	* Any unknown messages will be ignored (and failure
	311	* returned) during authentication.
	312	*/
	313	log("Unknown message during authentication: type %d", type);
	314	break;
	315	}
59c97189	316	if (!authctxt->valid && authenticated)
	317	fatal("INTERNAL ERROR: authenticated invalid user %s",
	318	authctxt->user);
a306f2dd	319
6005a40c	320	#ifdef HAVE_CYGWIN
94ec8c6b	321	if (authenticated &&
9cd45ea4	322	!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) {
3c62e7eb	323	packet_disconnect("Authentication rejected for uid %d.",
94ec8c6b	324	(int)pw->pw_uid);
3c62e7eb	325	authenticated = 0;
3c62e7eb	326	}
3c418020	327	#else
59c97189	328	/* Special handling for root */
	329	if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed())
	330	authenticated = 0;
3c418020	331	#endif
3c418020	332	#ifdef USE_PAM
94ec8c6b	333	if (authenticated && !do_pam_account(pw->pw_name, client_user))
	334	authenticated = 0;
	335	#endif
a306f2dd	336
59c97189	337	/* Log before sending the reply */
	338	auth_log(authctxt, authenticated, get_authname(type), info);
	339
a306f2dd	340	if (client_user != NULL) {
	341	xfree(client_user);
	342	client_user = NULL;
	343	}
	344
94ec8c6b	345	if (authenticated)
	346	return;
	347
b4b5d644	348	if (authctxt->failures++ > AUTH_FAIL_MAX) {
c1ef8333	349	#ifdef WITH_AIXAUTHENTICATE
61e96248	350	loginfailed(user,
	351	get_canonical_hostname(options.reverse_mapping_check),
	352	"ssh");
c1ef8333	353	#endif /* WITH_AIXAUTHENTICATE */
59c97189	354	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
c1ef8333	355	}
a306f2dd	356
a306f2dd	357	packet_start(SSH_SMSG_FAILURE);
	358	packet_send();
	359	packet_write_wait();
	360	}
	361	}
	362
	363	/*
	364	* Performs authentication of an incoming connection. Session key has already
	365	* been exchanged and encryption is enabled.
	366	*/
	367	void
	368	do_authentication()
	369	{
59c97189	370	Authctxt *authctxt;
59c97189	371	struct passwd *pw;
a306f2dd	372	int plen;
1e3b8b07	373	u_int ulen;
59c97189	374	char user, style = NULL;
a306f2dd	375
	376	/* Get the name of the user that we wish to log in as. */
	377	packet_read_expect(&plen, SSH_CMSG_USER);
	378
	379	/* Get the user name. */
	380	user = packet_get_string(&ulen);
	381	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
	382
59c97189	383	if ((style = strchr(user, ':')) != NULL)
	384	*style++ = 0;
	385
	386	authctxt = authctxt_new();
	387	authctxt->user = user;
	388	authctxt->style = style;
	389
a306f2dd	390	setproctitle("%s", user);
	391
	392	#ifdef AFS
	393	/* If machine has AFS, set process authentication group. */
	394	if (k_hasafs()) {
	395	k_setpag();
	396	k_unlog();
	397	}
	398	#endif /* AFS */
	399
	400	/* Verify that the user is a valid user. */
	401	pw = getpwnam(user);
94ec8c6b	402	if (pw && allowed_user(pw)) {
59c97189	403	authctxt->valid = 1;
59c97189	404	pw = pwcopy(pw);
94ec8c6b	405	} else {
59c97189	406	debug("do_authentication: illegal user %s", user);
94ec8c6b	407	pw = NULL;
94ec8c6b	408	}
59c97189	409	authctxt->pw = pw;
a306f2dd	410
a306f2dd	411	#ifdef USE_PAM
94ec8c6b	412	if (pw)
04fc7a67	413	start_pam(user);
a306f2dd	414	#endif
	415
	416	/*
	417	* If we are not running as root, the user must have the same uid as
94ec8c6b	418	* the server. (Unless you are running Windows)
a306f2dd	419	*/
94ec8c6b	420	#ifndef HAVE_CYGWIN
94ec8c6b	421	if (getuid() != 0 && pw && pw->pw_uid != getuid())
a306f2dd	422	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	423	#endif
a306f2dd	424
59c97189	425	/*
b4b5d644	426	* Loop until the user has been authenticated or the connection is
	427	* closed, do_authloop() returns only if authentication is successful
	428	*/
59c97189	429	do_authloop(authctxt);
a306f2dd	430
a306f2dd	431	/* The user has been authenticated and accepted. */
94ec8c6b	432	packet_start(SSH_SMSG_SUCCESS);
	433	packet_send();
	434	packet_write_wait();
59c97189	435
a306f2dd	436	#ifdef WITH_AIXAUTHENTICATE
c1ef8333	437	/* We don't have a pty yet, so just label the line as "ssh" */
61e96248	438	if (loginsuccess(authctxt->user,
	439	get_canonical_hostname(options.reverse_mapping_check),
	440	"ssh", &aixloginmsg) < 0)
c1ef8333	441	aixloginmsg = NULL;
a306f2dd	442	#endif /* WITH_AIXAUTHENTICATE */
59c97189	443
	444	xfree(authctxt->user);
	445	xfree(authctxt);
a306f2dd	446
	447	/* Perform session preparation. */
	448	do_authenticated(pw);
	449	}