[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 1.46 2003/01/23 00:03:00 djm 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 "channels.h"
#include "session.h"
#include "uidswap.h"
#include "monitor_wrap.h"

/* import */
extern ServerOptions options;

/*
 * 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;
	Key *client_host_key;
	BIGNUM *n;
	char *client_user, *password;
	char info[1024];
	u_int dlen;
	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
	    PRIVSEP(auth_password(authctxt, ""))) {
		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();

		/* 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_check_eom();

				if (kdata[0] == 4) { /* KRB_PROT_VERSION */
#ifdef KRB4
					KTEXT_ST tkt, reply;
					tkt.length = dlen;
					if (tkt.length < MAX_KTXT_LEN)
						memcpy(tkt.dat, kdata, tkt.length);

					if (PRIVSEP(auth_krb4(authctxt, &tkt,
					    &client_user, &reply))) {
						authenticated = 1;
						snprintf(info, sizeof(info),
						    " tktuser %.100s",
						    client_user);

						packet_start(
						    SSH_SMSG_AUTH_KERBEROS_RESPONSE);
						packet_put_string((char *)
						    reply.dat, reply.length);
						packet_send();
						packet_write_wait();
					}
#endif /* KRB4 */
				} else {
#ifdef KRB5
					krb5_data tkt, reply;
					tkt.length = dlen;
					tkt.data = kdata;

					if (PRIVSEP(auth_krb5(authctxt, &tkt,
					    &client_user, &reply))) {
						authenticated = 1;
						snprintf(info, sizeof(info),
						    " tktuser %.100s",
						    client_user);

 						/* Send response to client */
 						packet_start(
						    SSH_SMSG_AUTH_KERBEROS_RESPONSE);
 						packet_put_string((char *)
						    reply.data, reply.length);
 						packet_send();
 						packet_write_wait();

 						if (reply.length)
 							xfree(reply.data);
					}
#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_check_eom();

			/* 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 = key_new(KEY_RSA1);
			bits = packet_get_int();
			packet_get_bignum(client_host_key->rsa->e);
			packet_get_bignum(client_host_key->rsa->n);

			if (bits != BN_num_bits(client_host_key->rsa->n))
				verbose("Warning: keysize mismatch for client_host_key: "
				    "actual %d, announced %d",
				    BN_num_bits(client_host_key->rsa->n), bits);
			packet_check_eom();

			authenticated = auth_rhosts_rsa(pw, client_user,
			    client_host_key);
			key_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. */
			if ((n = BN_new()) == NULL)
				fatal("do_authloop: BN_new failed");
			packet_get_bignum(n);
			packet_check_eom();
			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_check_eom();

			/* Try authentication with the password. */
			authenticated = PRIVSEP(auth_password(authctxt, password));

			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);
				packet_check_eom();
				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 _UNICOS
		if (type == SSH_CMSG_AUTH_PASSWORD && !authenticated)
			cray_login_failure(authctxt->user, IA_UDBERR);
		if (authenticated && cray_access_denied(authctxt->user)) {
			authenticated = 0;
			fatal("Access denied for user %s.",authctxt->user);
		}
#endif /* _UNICOS */

#ifdef HAVE_CYGWIN
		if (authenticated &&
		    !check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD, pw)) {
			packet_disconnect("Authentication rejected for uid %d.",
			pw == NULL ? -1 : pw->pw_uid);
			authenticated = 0;
		}
#else
		/* Special handling for root */
		if (!use_privsep &&
		    authenticated && authctxt->pw->pw_uid == 0 &&
		    !auth_root_allowed(get_authname(type)))
			authenticated = 0;
#endif
#ifdef USE_PAM
		if (!use_privsep && 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) {
			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.
 */
Authctxt *
do_authentication(void)
{
	Authctxt *authctxt;
	u_int ulen;
	char *user, *style = NULL;

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

	/* Get the user name. */
	user = packet_get_string(&ulen);
	packet_check_eom();

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

#ifdef KRB5
	/* XXX - SSH.com Kerberos v5 braindeath. */
	if ((datafellows & SSH_BUG_K5USER) &&
	    options.kerberos_authentication) {
		char *p;
		if ((p = strchr(user, '@')) != NULL)
			*p = '\0';
	}
#endif

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

	/* Verify that the user is a valid user. */
	if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL)
		authctxt->valid = 1;
	else
		debug("do_authentication: illegal user %s", user);

	setproctitle("%s%s", authctxt->pw ? user : "unknown",
	    use_privsep ? " [net]" : "");

#ifdef USE_PAM
	PRIVSEP(start_pam(authctxt->pw == NULL ? "NOUSER" : 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 (!use_privsep && getuid() != 0 && authctxt->pw &&
	    authctxt->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();

	return (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"
0df3cb2b	13	RCSID("$OpenBSD: auth1.c,v 1.46 2003/01/23 00:03:00 djm 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"
7899c98f	25	#include "channels.h"
a306f2dd	26	#include "session.h"
ced49be2	27	#include "uidswap.h"
1853d1ef	28	#include "monitor_wrap.h"
a306f2dd	29
	30	/* import */
	31	extern ServerOptions options;
94ec8c6b	32
a306f2dd	33	/*
	34	* convert ssh auth msg type into description
	35	*/
396c147e	36	static char *
a306f2dd	37	get_authname(int type)
	38	{
	39	static char buf[1024];
	40	switch (type) {
	41	case SSH_CMSG_AUTH_PASSWORD:
	42	return "password";
	43	case SSH_CMSG_AUTH_RSA:
	44	return "rsa";
	45	case SSH_CMSG_AUTH_RHOSTS_RSA:
	46	return "rhosts-rsa";
	47	case SSH_CMSG_AUTH_RHOSTS:
	48	return "rhosts";
59c97189	49	case SSH_CMSG_AUTH_TIS:
	50	case SSH_CMSG_AUTH_TIS_RESPONSE:
	51	return "challenge-response";
ced49be2	52	#if defined(KRB4) \|\| defined(KRB5)
a306f2dd	53	case SSH_CMSG_AUTH_KERBEROS:
a306f2dd	54	return "kerberos";
a306f2dd	55	#endif
	56	}
	57	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	58	return buf;
	59	}
	60
	61	/*
59c97189	62	* read packets, try to authenticate the user and
59c97189	63	* return only if authentication is successful
a306f2dd	64	*/
396c147e	65	static void
59c97189	66	do_authloop(Authctxt *authctxt)
a306f2dd	67	{
94ec8c6b	68	int authenticated = 0;
1e3b8b07	69	u_int bits;
b775c6f2	70	Key *client_host_key;
a306f2dd	71	BIGNUM *n;
94ec8c6b	72	char client_user, password;
59c97189	73	char info[1024];
1e3b8b07	74	u_int dlen;
1e3b8b07	75	u_int ulen;
a306f2dd	76	int type = 0;
59c97189	77	struct passwd *pw = authctxt->pw;
	78
	79	debug("Attempting authentication for %s%.100s.",
184eed6a	80	authctxt->valid ? "" : "illegal user ", authctxt->user);
59c97189	81
	82	/* If the user has no password, accept authentication immediately. */
	83	if (options.password_authentication &&
ced49be2	84	#if defined(KRB4) \|\| defined(KRB5)
59c97189	85	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
59c97189	86	#endif
1853d1ef	87	PRIVSEP(auth_password(authctxt, ""))) {
59c97189	88	auth_log(authctxt, 1, "without authentication", "");
	89	return;
	90	}
a306f2dd	91
	92	/* Indicate that authentication is needed. */
	93	packet_start(SSH_SMSG_FAILURE);
	94	packet_send();
	95	packet_write_wait();
	96
94ec8c6b	97	client_user = NULL;
94ec8c6b	98
59c97189	99	for (;;) {
94ec8c6b	100	/* default to fail */
	101	authenticated = 0;
	102
59c97189	103	info[0] = '\0';
a306f2dd	104
a306f2dd	105	/* Get a packet from the client. */
54a5250f	106	type = packet_read();
a306f2dd	107
	108	/* Process the packet. */
	109	switch (type) {
a306f2dd	110
ced49be2	111	#if defined(KRB4) \|\| defined(KRB5)
a306f2dd	112	case SSH_CMSG_AUTH_KERBEROS:
a306f2dd	113	if (!options.kerberos_authentication) {
a306f2dd	114	verbose("Kerberos authentication disabled.");
a306f2dd	115	} else {
ced49be2	116	char *kdata = packet_get_string(&dlen);
95500969	117	packet_check_eom();
184eed6a	118
ced49be2	119	if (kdata[0] == 4) { /* KRB_PROT_VERSION */
ced49be2	120	#ifdef KRB4
2db9d8aa	121	KTEXT_ST tkt, reply;
ced49be2	122	tkt.length = dlen;
	123	if (tkt.length < MAX_KTXT_LEN)
	124	memcpy(tkt.dat, kdata, tkt.length);
184eed6a	125
2db9d8aa	126	if (PRIVSEP(auth_krb4(authctxt, &tkt,
2db9d8aa	127	&client_user, &reply))) {
ced49be2	128	authenticated = 1;
	129	snprintf(info, sizeof(info),
	130	" tktuser %.100s",
	131	client_user);
2db9d8aa	132
	133	packet_start(
	134	SSH_SMSG_AUTH_KERBEROS_RESPONSE);
	135	packet_put_string((char *)
	136	reply.dat, reply.length);
	137	packet_send();
	138	packet_write_wait();
94ec8c6b	139	}
ced49be2	140	#endif /* KRB4 */
	141	} else {
	142	#ifdef KRB5
696f6bef	143	krb5_data tkt, reply;
ced49be2	144	tkt.length = dlen;
ced49be2	145	tkt.data = kdata;
184eed6a	146
696f6bef	147	if (PRIVSEP(auth_krb5(authctxt, &tkt,
696f6bef	148	&client_user, &reply))) {
ced49be2	149	authenticated = 1;
	150	snprintf(info, sizeof(info),
	151	" tktuser %.100s",
	152	client_user);
b77a87e5	153
696f6bef	154	/* Send response to client */
	155	packet_start(
	156	SSH_SMSG_AUTH_KERBEROS_RESPONSE);
	157	packet_put_string((char *)
	158	reply.data, reply.length);
	159	packet_send();
	160	packet_write_wait();
	161
	162	if (reply.length)
	163	xfree(reply.data);
ced49be2	164	}
ced49be2	165	#endif /* KRB5 */
a306f2dd	166	}
59c97189	167	xfree(kdata);
a306f2dd	168	}
a306f2dd	169	break;
ced49be2	170	#endif /* KRB4 \|\| KRB5 */
184eed6a	171
ced49be2	172	#if defined(AFS) \|\| defined(KRB5)
	173	/* XXX - punt on backward compatibility here. */
	174	case SSH_CMSG_HAVE_KERBEROS_TGT:
	175	packet_send_debug("Kerberos TGT passing disabled before authentication.");
	176	break;
	177	#ifdef AFS
	178	case SSH_CMSG_HAVE_AFS_TOKEN:
	179	packet_send_debug("AFS token passing disabled before authentication.");
	180	break;
	181	#endif /* AFS */
	182	#endif /* AFS \|\| KRB5 */
184eed6a	183
a306f2dd	184	case SSH_CMSG_AUTH_RHOSTS:
	185	if (!options.rhosts_authentication) {
	186	verbose("Rhosts authentication disabled.");
	187	break;
	188	}
	189	/*
	190	* Get client user name. Note that we just have to
	191	* trust the client; this is one reason why rhosts
	192	* authentication is insecure. (Another is
	193	* IP-spoofing on a local network.)
	194	*/
	195	client_user = packet_get_string(&ulen);
95500969	196	packet_check_eom();
a306f2dd	197
94ec8c6b	198	/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
a306f2dd	199	authenticated = auth_rhosts(pw, client_user);
a306f2dd	200
59c97189	201	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	202	break;
	203
	204	case SSH_CMSG_AUTH_RHOSTS_RSA:
	205	if (!options.rhosts_rsa_authentication) {
	206	verbose("Rhosts with RSA authentication disabled.");
	207	break;
	208	}
	209	/*
	210	* Get client user name. Note that we just have to
	211	* trust the client; root on the client machine can
	212	* claim to be any user.
	213	*/
	214	client_user = packet_get_string(&ulen);
	215
	216	/* Get the client host key. */
b775c6f2	217	client_host_key = key_new(KEY_RSA1);
a306f2dd	218	bits = packet_get_int();
20b279e6	219	packet_get_bignum(client_host_key->rsa->e);
20b279e6	220	packet_get_bignum(client_host_key->rsa->n);
a306f2dd	221
b775c6f2	222	if (bits != BN_num_bits(client_host_key->rsa->n))
94ec8c6b	223	verbose("Warning: keysize mismatch for client_host_key: "
b775c6f2	224	"actual %d, announced %d",
7203d6bb	225	BN_num_bits(client_host_key->rsa->n), bits);
95500969	226	packet_check_eom();
a306f2dd	227
b775c6f2	228	authenticated = auth_rhosts_rsa(pw, client_user,
dc421aa3	229	client_host_key);
b775c6f2	230	key_free(client_host_key);
a306f2dd	231
59c97189	232	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	233	break;
	234
	235	case SSH_CMSG_AUTH_RSA:
	236	if (!options.rsa_authentication) {
	237	verbose("RSA authentication disabled.");
	238	break;
	239	}
	240	/* RSA authentication requested. */
b775c6f2	241	if ((n = BN_new()) == NULL)
b775c6f2	242	fatal("do_authloop: BN_new failed");
20b279e6	243	packet_get_bignum(n);
95500969	244	packet_check_eom();
a306f2dd	245	authenticated = auth_rsa(pw, n);
	246	BN_clear_free(n);
	247	break;
	248
	249	case SSH_CMSG_AUTH_PASSWORD:
	250	if (!options.password_authentication) {
	251	verbose("Password authentication disabled.");
	252	break;
	253	}
	254	/*
	255	* Read user password. It is in plain text, but was
	256	* transmitted over the encrypted channel so it is
	257	* not visible to an outside observer.
	258	*/
	259	password = packet_get_string(&dlen);
95500969	260	packet_check_eom();
a306f2dd	261
b4b5d644	262	/* Try authentication with the password. */
1853d1ef	263	authenticated = PRIVSEP(auth_password(authctxt, password));
a306f2dd	264
	265	memset(password, 0, strlen(password));
	266	xfree(password);
	267	break;
	268
a306f2dd	269	case SSH_CMSG_AUTH_TIS:
a306f2dd	270	debug("rcvd SSH_CMSG_AUTH_TIS");
5ba55ada	271	if (options.challenge_response_authentication == 1) {
5ba55ada	272	char *challenge = get_challenge(authctxt);
59c97189	273	if (challenge != NULL) {
59c97189	274	debug("sending challenge '%s'", challenge);
a306f2dd	275	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
59c97189	276	packet_put_cstring(challenge);
5ba55ada	277	xfree(challenge);
a306f2dd	278	packet_send();
	279	packet_write_wait();
	280	continue;
	281	}
	282	}
	283	break;
	284	case SSH_CMSG_AUTH_TIS_RESPONSE:
	285	debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
5ba55ada	286	if (options.challenge_response_authentication == 1) {
a306f2dd	287	char *response = packet_get_string(&dlen);
95500969	288	packet_check_eom();
59c97189	289	authenticated = verify_response(authctxt, response);
59c97189	290	memset(response, 'r', dlen);
a306f2dd	291	xfree(response);
	292	}
	293	break;
a306f2dd	294
	295	default:
	296	/*
	297	* Any unknown messages will be ignored (and failure
	298	* returned) during authentication.
	299	*/
	300	log("Unknown message during authentication: type %d", type);
	301	break;
	302	}
af774732	303	#ifdef BSD_AUTH
	304	if (authctxt->as) {
	305	auth_close(authctxt->as);
	306	authctxt->as = NULL;
	307	}
	308	#endif
59c97189	309	if (!authctxt->valid && authenticated)
	310	fatal("INTERNAL ERROR: authenticated invalid user %s",
	311	authctxt->user);
a306f2dd	312
ef51930f	313	#ifdef _UNICOS
	314	if (type == SSH_CMSG_AUTH_PASSWORD && !authenticated)
	315	cray_login_failure(authctxt->user, IA_UDBERR);
	316	if (authenticated && cray_access_denied(authctxt->user)) {
	317	authenticated = 0;
	318	fatal("Access denied for user %s.",authctxt->user);
	319	}
	320	#endif /* _UNICOS */
	321
2b87da3b	322	#ifdef HAVE_CYGWIN
2b87da3b	323	if (authenticated &&
e9571a2c	324	!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD, pw)) {
3c62e7eb	325	packet_disconnect("Authentication rejected for uid %d.",
e9571a2c	326	pw == NULL ? -1 : pw->pw_uid);
3c62e7eb	327	authenticated = 0;
3c62e7eb	328	}
3c418020	329	#else
59c97189	330	/* Special handling for root */
848bf884	331	if (!use_privsep &&
848bf884	332	authenticated && authctxt->pw->pw_uid == 0 &&
15853e93	333	!auth_root_allowed(get_authname(type)))
59c97189	334	authenticated = 0;
3c418020	335	#endif
2b87da3b	336	#ifdef USE_PAM
ad200abb	337	if (!use_privsep && authenticated &&
ad200abb	338	!do_pam_account(pw->pw_name, client_user))
94ec8c6b	339	authenticated = 0;
94ec8c6b	340	#endif
a306f2dd	341
59c97189	342	/* Log before sending the reply */
	343	auth_log(authctxt, authenticated, get_authname(type), info);
	344
a306f2dd	345	if (client_user != NULL) {
	346	xfree(client_user);
	347	client_user = NULL;
	348	}
	349
94ec8c6b	350	if (authenticated)
	351	return;
	352
b4b5d644	353	if (authctxt->failures++ > AUTH_FAIL_MAX) {
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	*/
1b34c1b3	367	Authctxt *
d5bb9418	368	do_authentication(void)
a306f2dd	369	{
59c97189	370	Authctxt *authctxt;
1e3b8b07	371	u_int ulen;
f8d99a32	372	char user, style = NULL;
a306f2dd	373
a306f2dd	374	/* Get the name of the user that we wish to log in as. */
54a5250f	375	packet_read_expect(SSH_CMSG_USER);
a306f2dd	376
	377	/* Get the user name. */
	378	user = packet_get_string(&ulen);
95500969	379	packet_check_eom();
a306f2dd	380
59c97189	381	if ((style = strchr(user, ':')) != NULL)
ced49be2	382	*style++ = '\0';
59c97189	383
f8d99a32	384	#ifdef KRB5
ced49be2	385	/* XXX - SSH.com Kerberos v5 braindeath. */
f8d99a32	386	if ((datafellows & SSH_BUG_K5USER) &&
	387	options.kerberos_authentication) {
	388	char *p;
	389	if ((p = strchr(user, '@')) != NULL)
	390	*p = '\0';
	391	}
	392	#endif
184eed6a	393
59c97189	394	authctxt = authctxt_new();
	395	authctxt->user = user;
	396	authctxt->style = style;
	397
a306f2dd	398	/* Verify that the user is a valid user. */
5f1f36b5	399	if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL)
59c97189	400	authctxt->valid = 1;
5f1f36b5	401	else
59c97189	402	debug("do_authentication: illegal user %s", user);
a306f2dd	403
5f1f36b5	404	setproctitle("%s%s", authctxt->pw ? user : "unknown",
1853d1ef	405	use_privsep ? " [net]" : "");
6172e290	406
a306f2dd	407	#ifdef USE_PAM
ad200abb	408	PRIVSEP(start_pam(authctxt->pw == NULL ? "NOUSER" : user));
a306f2dd	409	#endif
	410
	411	/*
	412	* If we are not running as root, the user must have the same uid as
94ec8c6b	413	* the server. (Unless you are running Windows)
a306f2dd	414	*/
94ec8c6b	415	#ifndef HAVE_CYGWIN
5f1f36b5	416	if (!use_privsep && getuid() != 0 && authctxt->pw &&
5f1f36b5	417	authctxt->pw->pw_uid != getuid())
a306f2dd	418	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	419	#endif
a306f2dd	420
59c97189	421	/*
b4b5d644	422	* Loop until the user has been authenticated or the connection is
	423	* closed, do_authloop() returns only if authentication is successful
	424	*/
59c97189	425	do_authloop(authctxt);
a306f2dd	426
a306f2dd	427	/* The user has been authenticated and accepted. */
94ec8c6b	428	packet_start(SSH_SMSG_SUCCESS);
	429	packet_send();
	430	packet_write_wait();
59c97189	431
1b34c1b3	432	return (authctxt);
a306f2dd	433	}