[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 1.25 2001/06/26 16:15:23 dugsong Exp $");

#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"
#include "misc.h"
#include "uidswap.h"

/* import */
extern ServerOptions options;

#ifdef WITH_AIXAUTHENTICATE
extern char *aixloginmsg;
#endif /* WITH_AIXAUTHENTICATE */

/*
 * convert ssh auth msg type into description
 */
static 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";
#if defined(KRB4) || defined(KRB5)
	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
 */
static 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 &&
#if defined(KRB4) || defined(KRB5)
	    (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif
#ifdef USE_PAM
	    auth_pam_password(pw, "")) {
#elif defined(HAVE_OSF_SIA)
	    0) {
#else
	    auth_password(authctxt, "")) {
#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) {

#if defined(KRB4) || defined(KRB5)
		case SSH_CMSG_AUTH_KERBEROS:
			if (!options.kerberos_authentication) {
				verbose("Kerberos authentication disabled.");
			} else {
				char *kdata = packet_get_string(&dlen);
				
				packet_integrity_check(plen, 4 + dlen, type);
				
				if (kdata[0] == 4) { /* KRB_PROT_VERSION */
#ifdef KRB4
					KTEXT_ST tkt;
					
					tkt.length = dlen;
					if (tkt.length < MAX_KTXT_LEN)
						memcpy(tkt.dat, kdata, tkt.length);
					
					if (auth_krb4(authctxt, &tkt, &client_user)) {
						authenticated = 1;
						snprintf(info, sizeof(info),
						    " tktuser %.100s",
						    client_user);
						xfree(client_user);
					}
#endif /* KRB4 */
				} else {
#ifdef KRB5
					krb5_data tkt;
					tkt.length = dlen;
					tkt.data = kdata;
					
					if (auth_krb5(authctxt, &tkt, &client_user)) {
						authenticated = 1;
						snprintf(info, sizeof(info),
						    " tktuser %.100s",
						    client_user);
						xfree(client_user);
					}
#endif /* KRB5 */
				}
				xfree(kdata);
			}
			break;
#endif /* KRB4 || KRB5 */
			
#if defined(AFS) || defined(KRB5)
			/* XXX - punt on backward compatibility here. */
		case SSH_CMSG_HAVE_KERBEROS_TGT:
			packet_send_debug("Kerberos TGT passing disabled before authentication.");
			break;
#ifdef AFS
		case SSH_CMSG_HAVE_AFS_TOKEN:
			packet_send_debug("AFS token passing disabled before authentication.");
			break;
#endif /* AFS */
#endif /* AFS || KRB5 */
			
		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 */
			authenticated = auth_sia_password(authctxt->user, 
			    password);
#else /* !USE_PAM && !HAVE_OSF_SIA */
			/* Try authentication with the password. */
			authenticated = auth_password(authctxt, 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_response_authentication == 1) {
				char *challenge = get_challenge(authctxt);
				if (challenge != NULL) {
					debug("sending challenge '%s'", challenge);
					packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
					packet_put_cstring(challenge);
					xfree(challenge);
					packet_send();
					packet_write_wait();
					continue;
				}
			}
			break;
		case SSH_CMSG_AUTH_TIS_RESPONSE:
			debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
			if (options.challenge_response_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;
		}
#ifdef BSD_AUTH
		if (authctxt->as) {
			auth_close(authctxt->as);
			authctxt->as = NULL;
		}
#endif
		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(get_authname(type)))
			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(authctxt->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 *p, *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';

	/* XXX - SSH.com Kerberos v5 braindeath. */
	if ((p = strchr(user, '@')) != NULL)
		*p = '\0';
	
	authctxt = authctxt_new();
	authctxt->user = user;
	authctxt->style = style;

	/* 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;

	setproctitle("%s", pw ? user : "unknown");

#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 */

	/* Perform session preparation. */
	do_authenticated(authctxt);
}
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"
ced49be2	13	RCSID("$OpenBSD: auth1.c,v 1.25 2001/06/26 16:15:23 dugsong Exp $");
94ec8c6b	14
a306f2dd	15	#include "xmalloc.h"
a306f2dd	16	#include "rsa.h"
42f11eb2	17	#include "ssh1.h"
a306f2dd	18	#include "packet.h"
a306f2dd	19	#include "buffer.h"
a306f2dd	20	#include "mpaux.h"
42f11eb2	21	#include "log.h"
a306f2dd	22	#include "servconf.h"
	23	#include "compat.h"
	24	#include "auth.h"
	25	#include "session.h"
3b1a83df	26	#include "misc.h"
ced49be2	27	#include "uidswap.h"
a306f2dd	28
	29	/* import */
	30	extern ServerOptions options;
94ec8c6b	31
	32	#ifdef WITH_AIXAUTHENTICATE
	33	extern char *aixloginmsg;
	34	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	35
	36	/*
	37	* convert ssh auth msg type into description
	38	*/
396c147e	39	static char *
a306f2dd	40	get_authname(int type)
	41	{
	42	static char buf[1024];
	43	switch (type) {
	44	case SSH_CMSG_AUTH_PASSWORD:
	45	return "password";
	46	case SSH_CMSG_AUTH_RSA:
	47	return "rsa";
	48	case SSH_CMSG_AUTH_RHOSTS_RSA:
	49	return "rhosts-rsa";
	50	case SSH_CMSG_AUTH_RHOSTS:
	51	return "rhosts";
59c97189	52	case SSH_CMSG_AUTH_TIS:
	53	case SSH_CMSG_AUTH_TIS_RESPONSE:
	54	return "challenge-response";
ced49be2	55	#if defined(KRB4) \|\| defined(KRB5)
a306f2dd	56	case SSH_CMSG_AUTH_KERBEROS:
a306f2dd	57	return "kerberos";
a306f2dd	58	#endif
	59	}
	60	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	61	return buf;
	62	}
	63
	64	/*
59c97189	65	* read packets, try to authenticate the user and
59c97189	66	* return only if authentication is successful
a306f2dd	67	*/
396c147e	68	static void
59c97189	69	do_authloop(Authctxt *authctxt)
a306f2dd	70	{
94ec8c6b	71	int authenticated = 0;
1e3b8b07	72	u_int bits;
a306f2dd	73	RSA *client_host_key;
a306f2dd	74	BIGNUM *n;
94ec8c6b	75	char client_user, password;
59c97189	76	char info[1024];
1e3b8b07	77	u_int dlen;
a306f2dd	78	int plen, nlen, elen;
1e3b8b07	79	u_int ulen;
a306f2dd	80	int type = 0;
59c97189	81	struct passwd *pw = authctxt->pw;
	82
	83	debug("Attempting authentication for %s%.100s.",
	84	authctxt->valid ? "" : "illegal user ", authctxt->user);
	85
	86	/* If the user has no password, accept authentication immediately. */
	87	if (options.password_authentication &&
ced49be2	88	#if defined(KRB4) \|\| defined(KRB5)
59c97189	89	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
59c97189	90	#endif
f4ebf0e8	91	#ifdef USE_PAM
8d60e965	92	auth_pam_password(pw, "")) {
b7ccb051	93	#elif defined(HAVE_OSF_SIA)
b7ccb051	94	0) {
59c97189	95	#else
af774732	96	auth_password(authctxt, "")) {
59c97189	97	#endif
	98	auth_log(authctxt, 1, "without authentication", "");
	99	return;
	100	}
a306f2dd	101
	102	/* Indicate that authentication is needed. */
	103	packet_start(SSH_SMSG_FAILURE);
	104	packet_send();
	105	packet_write_wait();
	106
94ec8c6b	107	client_user = NULL;
94ec8c6b	108
59c97189	109	for (;;) {
94ec8c6b	110	/* default to fail */
	111	authenticated = 0;
	112
59c97189	113	info[0] = '\0';
a306f2dd	114
	115	/* Get a packet from the client. */
	116	type = packet_read(&plen);
	117
	118	/* Process the packet. */
	119	switch (type) {
a306f2dd	120
ced49be2	121	#if defined(KRB4) \|\| defined(KRB5)
a306f2dd	122	case SSH_CMSG_AUTH_KERBEROS:
a306f2dd	123	if (!options.kerberos_authentication) {
a306f2dd	124	verbose("Kerberos authentication disabled.");
a306f2dd	125	} else {
ced49be2	126	char *kdata = packet_get_string(&dlen);
	127
	128	packet_integrity_check(plen, 4 + dlen, type);
	129
	130	if (kdata[0] == 4) { /* KRB_PROT_VERSION */
	131	#ifdef KRB4
	132	KTEXT_ST tkt;
	133
	134	tkt.length = dlen;
	135	if (tkt.length < MAX_KTXT_LEN)
	136	memcpy(tkt.dat, kdata, tkt.length);
	137
	138	if (auth_krb4(authctxt, &tkt, &client_user)) {
	139	authenticated = 1;
	140	snprintf(info, sizeof(info),
	141	" tktuser %.100s",
	142	client_user);
	143	xfree(client_user);
94ec8c6b	144	}
ced49be2	145	#endif /* KRB4 */
	146	} else {
	147	#ifdef KRB5
	148	krb5_data tkt;
	149	tkt.length = dlen;
	150	tkt.data = kdata;
	151
	152	if (auth_krb5(authctxt, &tkt, &client_user)) {
	153	authenticated = 1;
	154	snprintf(info, sizeof(info),
	155	" tktuser %.100s",
	156	client_user);
	157	xfree(client_user);
	158	}
	159	#endif /* KRB5 */
a306f2dd	160	}
59c97189	161	xfree(kdata);
a306f2dd	162	}
a306f2dd	163	break;
ced49be2	164	#endif /* KRB4 \|\| KRB5 */
	165
	166	#if defined(AFS) \|\| defined(KRB5)
	167	/* XXX - punt on backward compatibility here. */
	168	case SSH_CMSG_HAVE_KERBEROS_TGT:
	169	packet_send_debug("Kerberos TGT passing disabled before authentication.");
	170	break;
	171	#ifdef AFS
	172	case SSH_CMSG_HAVE_AFS_TOKEN:
	173	packet_send_debug("AFS token passing disabled before authentication.");
	174	break;
	175	#endif /* AFS */
	176	#endif /* AFS \|\| KRB5 */
	177
a306f2dd	178	case SSH_CMSG_AUTH_RHOSTS:
	179	if (!options.rhosts_authentication) {
	180	verbose("Rhosts authentication disabled.");
	181	break;
	182	}
	183	/*
	184	* Get client user name. Note that we just have to
	185	* trust the client; this is one reason why rhosts
	186	* authentication is insecure. (Another is
	187	* IP-spoofing on a local network.)
	188	*/
	189	client_user = packet_get_string(&ulen);
	190	packet_integrity_check(plen, 4 + ulen, type);
	191
94ec8c6b	192	/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
a306f2dd	193	authenticated = auth_rhosts(pw, client_user);
a306f2dd	194
59c97189	195	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	196	break;
	197
	198	case SSH_CMSG_AUTH_RHOSTS_RSA:
	199	if (!options.rhosts_rsa_authentication) {
	200	verbose("Rhosts with RSA authentication disabled.");
	201	break;
	202	}
	203	/*
	204	* Get client user name. Note that we just have to
	205	* trust the client; root on the client machine can
	206	* claim to be any user.
	207	*/
	208	client_user = packet_get_string(&ulen);
	209
	210	/* Get the client host key. */
	211	client_host_key = RSA_new();
	212	if (client_host_key == NULL)
	213	fatal("RSA_new failed");
	214	client_host_key->e = BN_new();
	215	client_host_key->n = BN_new();
	216	if (client_host_key->e == NULL \|\| client_host_key->n == NULL)
	217	fatal("BN_new failed");
	218	bits = packet_get_int();
	219	packet_get_bignum(client_host_key->e, &elen);
	220	packet_get_bignum(client_host_key->n, &nlen);
	221
	222	if (bits != BN_num_bits(client_host_key->n))
94ec8c6b	223	verbose("Warning: keysize mismatch for client_host_key: "
0b242b12	224	"actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
a306f2dd	225	packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
	226
	227	authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
	228	RSA_free(client_host_key);
	229
59c97189	230	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	231	break;
	232
	233	case SSH_CMSG_AUTH_RSA:
	234	if (!options.rsa_authentication) {
	235	verbose("RSA authentication disabled.");
	236	break;
	237	}
	238	/* RSA authentication requested. */
	239	n = BN_new();
	240	packet_get_bignum(n, &nlen);
	241	packet_integrity_check(plen, nlen, type);
	242	authenticated = auth_rsa(pw, n);
	243	BN_clear_free(n);
	244	break;
	245
	246	case SSH_CMSG_AUTH_PASSWORD:
	247	if (!options.password_authentication) {
	248	verbose("Password authentication disabled.");
	249	break;
	250	}
	251	/*
	252	* Read user password. It is in plain text, but was
	253	* transmitted over the encrypted channel so it is
	254	* not visible to an outside observer.
	255	*/
	256	password = packet_get_string(&dlen);
	257	packet_integrity_check(plen, 4 + dlen, type);
	258
	259	#ifdef USE_PAM
	260	/* Do PAM auth with password */
	261	authenticated = auth_pam_password(pw, password);
4d33e531	262	#elif defined(HAVE_OSF_SIA)
4d33e531	263	/* Do SIA auth with password */
b7ccb051	264	authenticated = auth_sia_password(authctxt->user,
b7ccb051	265	password);
4d33e531	266	#else /* !USE_PAM && !HAVE_OSF_SIA */
b4b5d644	267	/* Try authentication with the password. */
af774732	268	authenticated = auth_password(authctxt, password);
a306f2dd	269	#endif /* USE_PAM */
	270
	271	memset(password, 0, strlen(password));
	272	xfree(password);
	273	break;
	274
a306f2dd	275	case SSH_CMSG_AUTH_TIS:
a306f2dd	276	debug("rcvd SSH_CMSG_AUTH_TIS");
5ba55ada	277	if (options.challenge_response_authentication == 1) {
5ba55ada	278	char *challenge = get_challenge(authctxt);
59c97189	279	if (challenge != NULL) {
59c97189	280	debug("sending challenge '%s'", challenge);
a306f2dd	281	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
59c97189	282	packet_put_cstring(challenge);
5ba55ada	283	xfree(challenge);
a306f2dd	284	packet_send();
	285	packet_write_wait();
	286	continue;
	287	}
	288	}
	289	break;
	290	case SSH_CMSG_AUTH_TIS_RESPONSE:
	291	debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
5ba55ada	292	if (options.challenge_response_authentication == 1) {
a306f2dd	293	char *response = packet_get_string(&dlen);
59c97189	294	debug("got response '%s'", response);
a306f2dd	295	packet_integrity_check(plen, 4 + dlen, type);
59c97189	296	authenticated = verify_response(authctxt, response);
59c97189	297	memset(response, 'r', dlen);
a306f2dd	298	xfree(response);
	299	}
	300	break;
a306f2dd	301
	302	default:
	303	/*
	304	* Any unknown messages will be ignored (and failure
	305	* returned) during authentication.
	306	*/
	307	log("Unknown message during authentication: type %d", type);
	308	break;
	309	}
af774732	310	#ifdef BSD_AUTH
	311	if (authctxt->as) {
	312	auth_close(authctxt->as);
	313	authctxt->as = NULL;
	314	}
	315	#endif
59c97189	316	if (!authctxt->valid && authenticated)
	317	fatal("INTERNAL ERROR: authenticated invalid user %s",
	318	authctxt->user);
a306f2dd	319
2b87da3b	320	#ifdef HAVE_CYGWIN
2b87da3b	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 */
15853e93	329	if (authenticated && authctxt->pw->pw_uid == 0 &&
15853e93	330	!auth_root_allowed(get_authname(type)))
59c97189	331	authenticated = 0;
3c418020	332	#endif
2b87da3b	333	#ifdef USE_PAM
94ec8c6b	334	if (authenticated && !do_pam_account(pw->pw_name, client_user))
	335	authenticated = 0;
	336	#endif
a306f2dd	337
59c97189	338	/* Log before sending the reply */
	339	auth_log(authctxt, authenticated, get_authname(type), info);
	340
a306f2dd	341	if (client_user != NULL) {
	342	xfree(client_user);
	343	client_user = NULL;
	344	}
	345
94ec8c6b	346	if (authenticated)
	347	return;
	348
b4b5d644	349	if (authctxt->failures++ > AUTH_FAIL_MAX) {
2b87da3b	350	#ifdef WITH_AIXAUTHENTICATE
	351	loginfailed(authctxt->user,
	352	get_canonical_hostname(options.reverse_mapping_check),
61e96248	353	"ssh");
c1ef8333	354	#endif /* WITH_AIXAUTHENTICATE */
59c97189	355	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
c1ef8333	356	}
a306f2dd	357
a306f2dd	358	packet_start(SSH_SMSG_FAILURE);
	359	packet_send();
	360	packet_write_wait();
	361	}
	362	}
	363
	364	/*
	365	* Performs authentication of an incoming connection. Session key has already
	366	* been exchanged and encryption is enabled.
	367	*/
	368	void
	369	do_authentication()
	370	{
59c97189	371	Authctxt *authctxt;
59c97189	372	struct passwd *pw;
a306f2dd	373	int plen;
1e3b8b07	374	u_int ulen;
ced49be2	375	char p, user, *style = NULL;
a306f2dd	376
	377	/* Get the name of the user that we wish to log in as. */
	378	packet_read_expect(&plen, SSH_CMSG_USER);
	379
	380	/* Get the user name. */
	381	user = packet_get_string(&ulen);
	382	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
	383
59c97189	384	if ((style = strchr(user, ':')) != NULL)
ced49be2	385	*style++ = '\0';
59c97189	386
ced49be2	387	/* XXX - SSH.com Kerberos v5 braindeath. */
	388	if ((p = strchr(user, '@')) != NULL)
	389	*p = '\0';
	390
59c97189	391	authctxt = authctxt_new();
	392	authctxt->user = user;
	393	authctxt->style = style;
	394
a306f2dd	395	/* Verify that the user is a valid user. */
a306f2dd	396	pw = getpwnam(user);
94ec8c6b	397	if (pw && allowed_user(pw)) {
59c97189	398	authctxt->valid = 1;
59c97189	399	pw = pwcopy(pw);
94ec8c6b	400	} else {
59c97189	401	debug("do_authentication: illegal user %s", user);
94ec8c6b	402	pw = NULL;
94ec8c6b	403	}
59c97189	404	authctxt->pw = pw;
a306f2dd	405
6172e290	406	setproctitle("%s", pw ? user : "unknown");
6172e290	407
a306f2dd	408	#ifdef USE_PAM
94ec8c6b	409	if (pw)
04fc7a67	410	start_pam(user);
a306f2dd	411	#endif
	412
	413	/*
	414	* If we are not running as root, the user must have the same uid as
94ec8c6b	415	* the server. (Unless you are running Windows)
a306f2dd	416	*/
94ec8c6b	417	#ifndef HAVE_CYGWIN
94ec8c6b	418	if (getuid() != 0 && pw && pw->pw_uid != getuid())
a306f2dd	419	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	420	#endif
a306f2dd	421
59c97189	422	/*
b4b5d644	423	* Loop until the user has been authenticated or the connection is
	424	* closed, do_authloop() returns only if authentication is successful
	425	*/
59c97189	426	do_authloop(authctxt);
a306f2dd	427
a306f2dd	428	/* The user has been authenticated and accepted. */
94ec8c6b	429	packet_start(SSH_SMSG_SUCCESS);
	430	packet_send();
	431	packet_write_wait();
59c97189	432
a306f2dd	433	#ifdef WITH_AIXAUTHENTICATE
c1ef8333	434	/* We don't have a pty yet, so just label the line as "ssh" */
2b87da3b	435	if (loginsuccess(authctxt->user,
61e96248	436	get_canonical_hostname(options.reverse_mapping_check),
61e96248	437	"ssh", &aixloginmsg) < 0)
c1ef8333	438	aixloginmsg = NULL;
a306f2dd	439	#endif /* WITH_AIXAUTHENTICATE */
59c97189	440
a306f2dd	441	/* Perform session preparation. */
bb5639fe	442	do_authenticated(authctxt);
a306f2dd	443	}