[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 1.18 2001/02/22 21:59:43 markus 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"

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

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

/*
 * 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, "")) {
#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) {
#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 */
			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_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;
		}
#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 *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;

	/* 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 */

	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"
3b1a83df	13	RCSID("$OpenBSD: auth1.c,v 1.18 2001/02/22 21:59:43 markus 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"
a306f2dd	27
	28	/* import */
	29	extern ServerOptions options;
	30	extern char *forced_command;
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	*/
	39	char *
	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";
a306f2dd	55	#ifdef KRB4
	56	case SSH_CMSG_AUTH_KERBEROS:
	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	*/
a306f2dd	68	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 &&
	88	#ifdef KRB4
	89	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
	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) {
	120	#ifdef AFS
	121	case SSH_CMSG_HAVE_KERBEROS_TGT:
	122	if (!options.kerberos_tgt_passing) {
a306f2dd	123	verbose("Kerberos tgt passing disabled.");
	124	break;
	125	} else {
	126	/* Accept Kerberos tgt. */
	127	char *tgt = packet_get_string(&dlen);
	128	packet_integrity_check(plen, 4 + dlen, type);
	129	if (!auth_kerberos_tgt(pw, tgt))
59c97189	130	verbose("Kerberos tgt REFUSED for %.100s", authctxt->user);
a306f2dd	131	xfree(tgt);
	132	}
	133	continue;
	134
	135	case SSH_CMSG_HAVE_AFS_TOKEN:
	136	if (!options.afs_token_passing \|\| !k_hasafs()) {
a306f2dd	137	verbose("AFS token passing disabled.");
	138	break;
	139	} else {
	140	/* Accept AFS token. */
	141	char *token_string = packet_get_string(&dlen);
	142	packet_integrity_check(plen, 4 + dlen, type);
	143	if (!auth_afs_token(pw, token_string))
59c97189	144	verbose("AFS token REFUSED for %.100s", authctxt->user);
a306f2dd	145	xfree(token_string);
	146	}
	147	continue;
	148	#endif /* AFS */
	149	#ifdef KRB4
	150	case SSH_CMSG_AUTH_KERBEROS:
	151	if (!options.kerberos_authentication) {
a306f2dd	152	verbose("Kerberos authentication disabled.");
	153	break;
	154	} else {
	155	/* Try Kerberos v4 authentication. */
	156	KTEXT_ST auth;
	157	char *tkt_user = NULL;
1e3b8b07	158	char kdata = packet_get_string((u_int ) &auth.length);
a306f2dd	159	packet_integrity_check(plen, 4 + auth.length, type);
a306f2dd	160
59c97189	161	if (authctxt->valid) {
	162	if (auth.length < MAX_KTXT_LEN)
	163	memcpy(auth.dat, kdata, auth.length);
94ec8c6b	164	authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
94ec8c6b	165	if (authenticated) {
59c97189	166	snprintf(info, sizeof info,
59c97189	167	" tktuser %.100s", tkt_user);
94ec8c6b	168	xfree(tkt_user);
94ec8c6b	169	}
a306f2dd	170	}
59c97189	171	xfree(kdata);
a306f2dd	172	}
	173	break;
	174	#endif /* KRB4 */
	175
	176	case SSH_CMSG_AUTH_RHOSTS:
	177	if (!options.rhosts_authentication) {
	178	verbose("Rhosts authentication disabled.");
	179	break;
	180	}
	181	/*
	182	* Get client user name. Note that we just have to
	183	* trust the client; this is one reason why rhosts
	184	* authentication is insecure. (Another is
	185	* IP-spoofing on a local network.)
	186	*/
	187	client_user = packet_get_string(&ulen);
	188	packet_integrity_check(plen, 4 + ulen, type);
	189
94ec8c6b	190	/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
a306f2dd	191	authenticated = auth_rhosts(pw, client_user);
a306f2dd	192
59c97189	193	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	194	break;
	195
	196	case SSH_CMSG_AUTH_RHOSTS_RSA:
	197	if (!options.rhosts_rsa_authentication) {
	198	verbose("Rhosts with RSA authentication disabled.");
	199	break;
	200	}
	201	/*
	202	* Get client user name. Note that we just have to
	203	* trust the client; root on the client machine can
	204	* claim to be any user.
	205	*/
	206	client_user = packet_get_string(&ulen);
	207
	208	/* Get the client host key. */
	209	client_host_key = RSA_new();
	210	if (client_host_key == NULL)
	211	fatal("RSA_new failed");
	212	client_host_key->e = BN_new();
	213	client_host_key->n = BN_new();
	214	if (client_host_key->e == NULL \|\| client_host_key->n == NULL)
	215	fatal("BN_new failed");
	216	bits = packet_get_int();
	217	packet_get_bignum(client_host_key->e, &elen);
	218	packet_get_bignum(client_host_key->n, &nlen);
	219
	220	if (bits != BN_num_bits(client_host_key->n))
94ec8c6b	221	verbose("Warning: keysize mismatch for client_host_key: "
0b242b12	222	"actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
a306f2dd	223	packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
	224
	225	authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
	226	RSA_free(client_host_key);
	227
59c97189	228	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	229	break;
	230
	231	case SSH_CMSG_AUTH_RSA:
	232	if (!options.rsa_authentication) {
	233	verbose("RSA authentication disabled.");
	234	break;
	235	}
	236	/* RSA authentication requested. */
	237	n = BN_new();
	238	packet_get_bignum(n, &nlen);
	239	packet_integrity_check(plen, nlen, type);
	240	authenticated = auth_rsa(pw, n);
	241	BN_clear_free(n);
	242	break;
	243
	244	case SSH_CMSG_AUTH_PASSWORD:
	245	if (!options.password_authentication) {
	246	verbose("Password authentication disabled.");
	247	break;
	248	}
	249	/*
	250	* Read user password. It is in plain text, but was
	251	* transmitted over the encrypted channel so it is
	252	* not visible to an outside observer.
	253	*/
	254	password = packet_get_string(&dlen);
	255	packet_integrity_check(plen, 4 + dlen, type);
	256
	257	#ifdef USE_PAM
	258	/* Do PAM auth with password */
	259	authenticated = auth_pam_password(pw, password);
4d33e531	260	#elif defined(HAVE_OSF_SIA)
4d33e531	261	/* Do SIA auth with password */
b7ccb051	262	authenticated = auth_sia_password(authctxt->user,
b7ccb051	263	password);
4d33e531	264	#else /* !USE_PAM && !HAVE_OSF_SIA */
b4b5d644	265	/* Try authentication with the password. */
af774732	266	authenticated = auth_password(authctxt, password);
a306f2dd	267	#endif /* USE_PAM */
	268
	269	memset(password, 0, strlen(password));
	270	xfree(password);
	271	break;
	272
a306f2dd	273	case SSH_CMSG_AUTH_TIS:
a306f2dd	274	debug("rcvd SSH_CMSG_AUTH_TIS");
d464095c	275	if (options.challenge_reponse_authentication == 1) {
59c97189	276	char *challenge = get_challenge(authctxt, authctxt->style);
	277	if (challenge != NULL) {
	278	debug("sending challenge '%s'", challenge);
a306f2dd	279	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
59c97189	280	packet_put_cstring(challenge);
a306f2dd	281	packet_send();
	282	packet_write_wait();
	283	continue;
	284	}
	285	}
	286	break;
	287	case SSH_CMSG_AUTH_TIS_RESPONSE:
	288	debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
d464095c	289	if (options.challenge_reponse_authentication == 1) {
a306f2dd	290	char *response = packet_get_string(&dlen);
59c97189	291	debug("got response '%s'", response);
a306f2dd	292	packet_integrity_check(plen, 4 + dlen, type);
59c97189	293	authenticated = verify_response(authctxt, response);
59c97189	294	memset(response, 'r', dlen);
a306f2dd	295	xfree(response);
	296	}
	297	break;
a306f2dd	298
	299	default:
	300	/*
	301	* Any unknown messages will be ignored (and failure
	302	* returned) during authentication.
	303	*/
	304	log("Unknown message during authentication: type %d", type);
	305	break;
	306	}
af774732	307	#ifdef BSD_AUTH
	308	if (authctxt->as) {
	309	auth_close(authctxt->as);
	310	authctxt->as = NULL;
	311	}
	312	#endif
59c97189	313	if (!authctxt->valid && authenticated)
	314	fatal("INTERNAL ERROR: authenticated invalid user %s",
	315	authctxt->user);
a306f2dd	316
2b87da3b	317	#ifdef HAVE_CYGWIN
2b87da3b	318	if (authenticated &&
9cd45ea4	319	!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) {
3c62e7eb	320	packet_disconnect("Authentication rejected for uid %d.",
94ec8c6b	321	(int)pw->pw_uid);
3c62e7eb	322	authenticated = 0;
3c62e7eb	323	}
3c418020	324	#else
59c97189	325	/* Special handling for root */
15853e93	326	if (authenticated && authctxt->pw->pw_uid == 0 &&
15853e93	327	!auth_root_allowed(get_authname(type)))
59c97189	328	authenticated = 0;
3c418020	329	#endif
2b87da3b	330	#ifdef USE_PAM
94ec8c6b	331	if (authenticated && !do_pam_account(pw->pw_name, client_user))
	332	authenticated = 0;
	333	#endif
a306f2dd	334
59c97189	335	/* Log before sending the reply */
	336	auth_log(authctxt, authenticated, get_authname(type), info);
	337
a306f2dd	338	if (client_user != NULL) {
	339	xfree(client_user);
	340	client_user = NULL;
	341	}
	342
94ec8c6b	343	if (authenticated)
	344	return;
	345
b4b5d644	346	if (authctxt->failures++ > AUTH_FAIL_MAX) {
2b87da3b	347	#ifdef WITH_AIXAUTHENTICATE
	348	loginfailed(authctxt->user,
	349	get_canonical_hostname(options.reverse_mapping_check),
61e96248	350	"ssh");
c1ef8333	351	#endif /* WITH_AIXAUTHENTICATE */
59c97189	352	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
c1ef8333	353	}
a306f2dd	354
a306f2dd	355	packet_start(SSH_SMSG_FAILURE);
	356	packet_send();
	357	packet_write_wait();
	358	}
	359	}
	360
	361	/*
	362	* Performs authentication of an incoming connection. Session key has already
	363	* been exchanged and encryption is enabled.
	364	*/
	365	void
	366	do_authentication()
	367	{
59c97189	368	Authctxt *authctxt;
59c97189	369	struct passwd *pw;
a306f2dd	370	int plen;
1e3b8b07	371	u_int ulen;
59c97189	372	char user, style = NULL;
a306f2dd	373
	374	/* Get the name of the user that we wish to log in as. */
	375	packet_read_expect(&plen, SSH_CMSG_USER);
	376
	377	/* Get the user name. */
	378	user = packet_get_string(&ulen);
	379	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
	380
59c97189	381	if ((style = strchr(user, ':')) != NULL)
	382	*style++ = 0;
	383
	384	authctxt = authctxt_new();
	385	authctxt->user = user;
	386	authctxt->style = style;
	387
a306f2dd	388	/* Verify that the user is a valid user. */
a306f2dd	389	pw = getpwnam(user);
94ec8c6b	390	if (pw && allowed_user(pw)) {
59c97189	391	authctxt->valid = 1;
59c97189	392	pw = pwcopy(pw);
94ec8c6b	393	} else {
59c97189	394	debug("do_authentication: illegal user %s", user);
94ec8c6b	395	pw = NULL;
94ec8c6b	396	}
59c97189	397	authctxt->pw = pw;
a306f2dd	398
6172e290	399	setproctitle("%s", pw ? user : "unknown");
6172e290	400
a306f2dd	401	#ifdef USE_PAM
94ec8c6b	402	if (pw)
04fc7a67	403	start_pam(user);
a306f2dd	404	#endif
	405
	406	/*
	407	* If we are not running as root, the user must have the same uid as
94ec8c6b	408	* the server. (Unless you are running Windows)
a306f2dd	409	*/
94ec8c6b	410	#ifndef HAVE_CYGWIN
94ec8c6b	411	if (getuid() != 0 && pw && pw->pw_uid != getuid())
a306f2dd	412	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	413	#endif
a306f2dd	414
59c97189	415	/*
b4b5d644	416	* Loop until the user has been authenticated or the connection is
	417	* closed, do_authloop() returns only if authentication is successful
	418	*/
59c97189	419	do_authloop(authctxt);
a306f2dd	420
a306f2dd	421	/* The user has been authenticated and accepted. */
94ec8c6b	422	packet_start(SSH_SMSG_SUCCESS);
	423	packet_send();
	424	packet_write_wait();
59c97189	425
a306f2dd	426	#ifdef WITH_AIXAUTHENTICATE
c1ef8333	427	/* We don't have a pty yet, so just label the line as "ssh" */
2b87da3b	428	if (loginsuccess(authctxt->user,
61e96248	429	get_canonical_hostname(options.reverse_mapping_check),
61e96248	430	"ssh", &aixloginmsg) < 0)
c1ef8333	431	aixloginmsg = NULL;
a306f2dd	432	#endif /* WITH_AIXAUTHENTICATE */
59c97189	433
	434	xfree(authctxt->user);
	435	xfree(authctxt);
a306f2dd	436
	437	/* Perform session preparation. */
	438	do_authenticated(pw);
	439	}