[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 1.15 2001/02/07 22:35:45 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"

/* 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(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 */
			authenticated = auth_sia_password(authctxt->user, 
			    password);
#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(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;

	setproctitle("%s", user);

	/* 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"
abf1f107	13	RCSID("$OpenBSD: auth1.c,v 1.15 2001/02/07 22:35:45 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"
	26
	27	/* import */
	28	extern ServerOptions options;
	29	extern char *forced_command;
94ec8c6b	30
	31	#ifdef WITH_AIXAUTHENTICATE
	32	extern char *aixloginmsg;
	33	#endif /* WITH_AIXAUTHENTICATE */
a306f2dd	34
	35	/*
	36	* convert ssh auth msg type into description
	37	*/
	38	char *
	39	get_authname(int type)
	40	{
	41	static char buf[1024];
	42	switch (type) {
	43	case SSH_CMSG_AUTH_PASSWORD:
	44	return "password";
	45	case SSH_CMSG_AUTH_RSA:
	46	return "rsa";
	47	case SSH_CMSG_AUTH_RHOSTS_RSA:
	48	return "rhosts-rsa";
	49	case SSH_CMSG_AUTH_RHOSTS:
	50	return "rhosts";
59c97189	51	case SSH_CMSG_AUTH_TIS:
	52	case SSH_CMSG_AUTH_TIS_RESPONSE:
	53	return "challenge-response";
a306f2dd	54	#ifdef KRB4
	55	case SSH_CMSG_AUTH_KERBEROS:
	56	return "kerberos";
a306f2dd	57	#endif
	58	}
	59	snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
	60	return buf;
	61	}
	62
	63	/*
59c97189	64	* read packets, try to authenticate the user and
59c97189	65	* return only if authentication is successful
a306f2dd	66	*/
a306f2dd	67	void
59c97189	68	do_authloop(Authctxt *authctxt)
a306f2dd	69	{
94ec8c6b	70	int authenticated = 0;
1e3b8b07	71	u_int bits;
a306f2dd	72	RSA *client_host_key;
a306f2dd	73	BIGNUM *n;
94ec8c6b	74	char client_user, password;
59c97189	75	char info[1024];
1e3b8b07	76	u_int dlen;
a306f2dd	77	int plen, nlen, elen;
1e3b8b07	78	u_int ulen;
a306f2dd	79	int type = 0;
59c97189	80	struct passwd *pw = authctxt->pw;
	81
	82	debug("Attempting authentication for %s%.100s.",
	83	authctxt->valid ? "" : "illegal user ", authctxt->user);
	84
	85	/* If the user has no password, accept authentication immediately. */
	86	if (options.password_authentication &&
	87	#ifdef KRB4
	88	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
	89	#endif
f4ebf0e8	90	#ifdef USE_PAM
8d60e965	91	auth_pam_password(pw, "")) {
b7ccb051	92	#elif defined(HAVE_OSF_SIA)
b7ccb051	93	0) {
59c97189	94	#else
	95	auth_password(pw, "")) {
	96	#endif
	97	auth_log(authctxt, 1, "without authentication", "");
	98	return;
	99	}
a306f2dd	100
	101	/* Indicate that authentication is needed. */
	102	packet_start(SSH_SMSG_FAILURE);
	103	packet_send();
	104	packet_write_wait();
	105
94ec8c6b	106	client_user = NULL;
94ec8c6b	107
59c97189	108	for (;;) {
94ec8c6b	109	/* default to fail */
	110	authenticated = 0;
	111
59c97189	112	info[0] = '\0';
a306f2dd	113
	114	/* Get a packet from the client. */
	115	type = packet_read(&plen);
	116
	117	/* Process the packet. */
	118	switch (type) {
	119	#ifdef AFS
	120	case SSH_CMSG_HAVE_KERBEROS_TGT:
	121	if (!options.kerberos_tgt_passing) {
a306f2dd	122	verbose("Kerberos tgt passing disabled.");
	123	break;
	124	} else {
	125	/* Accept Kerberos tgt. */
	126	char *tgt = packet_get_string(&dlen);
	127	packet_integrity_check(plen, 4 + dlen, type);
	128	if (!auth_kerberos_tgt(pw, tgt))
59c97189	129	verbose("Kerberos tgt REFUSED for %.100s", authctxt->user);
a306f2dd	130	xfree(tgt);
	131	}
	132	continue;
	133
	134	case SSH_CMSG_HAVE_AFS_TOKEN:
	135	if (!options.afs_token_passing \|\| !k_hasafs()) {
a306f2dd	136	verbose("AFS token passing disabled.");
	137	break;
	138	} else {
	139	/* Accept AFS token. */
	140	char *token_string = packet_get_string(&dlen);
	141	packet_integrity_check(plen, 4 + dlen, type);
	142	if (!auth_afs_token(pw, token_string))
59c97189	143	verbose("AFS token REFUSED for %.100s", authctxt->user);
a306f2dd	144	xfree(token_string);
	145	}
	146	continue;
	147	#endif /* AFS */
	148	#ifdef KRB4
	149	case SSH_CMSG_AUTH_KERBEROS:
	150	if (!options.kerberos_authentication) {
a306f2dd	151	verbose("Kerberos authentication disabled.");
	152	break;
	153	} else {
	154	/* Try Kerberos v4 authentication. */
	155	KTEXT_ST auth;
	156	char *tkt_user = NULL;
1e3b8b07	157	char kdata = packet_get_string((u_int ) &auth.length);
a306f2dd	158	packet_integrity_check(plen, 4 + auth.length, type);
a306f2dd	159
59c97189	160	if (authctxt->valid) {
	161	if (auth.length < MAX_KTXT_LEN)
	162	memcpy(auth.dat, kdata, auth.length);
94ec8c6b	163	authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
94ec8c6b	164	if (authenticated) {
59c97189	165	snprintf(info, sizeof info,
59c97189	166	" tktuser %.100s", tkt_user);
94ec8c6b	167	xfree(tkt_user);
94ec8c6b	168	}
a306f2dd	169	}
59c97189	170	xfree(kdata);
a306f2dd	171	}
	172	break;
	173	#endif /* KRB4 */
	174
	175	case SSH_CMSG_AUTH_RHOSTS:
	176	if (!options.rhosts_authentication) {
	177	verbose("Rhosts authentication disabled.");
	178	break;
	179	}
	180	/*
	181	* Get client user name. Note that we just have to
	182	* trust the client; this is one reason why rhosts
	183	* authentication is insecure. (Another is
	184	* IP-spoofing on a local network.)
	185	*/
	186	client_user = packet_get_string(&ulen);
	187	packet_integrity_check(plen, 4 + ulen, type);
	188
94ec8c6b	189	/* Try to authenticate using /etc/hosts.equiv and .rhosts. */
a306f2dd	190	authenticated = auth_rhosts(pw, client_user);
a306f2dd	191
59c97189	192	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	193	break;
	194
	195	case SSH_CMSG_AUTH_RHOSTS_RSA:
	196	if (!options.rhosts_rsa_authentication) {
	197	verbose("Rhosts with RSA authentication disabled.");
	198	break;
	199	}
	200	/*
	201	* Get client user name. Note that we just have to
	202	* trust the client; root on the client machine can
	203	* claim to be any user.
	204	*/
	205	client_user = packet_get_string(&ulen);
	206
	207	/* Get the client host key. */
	208	client_host_key = RSA_new();
	209	if (client_host_key == NULL)
	210	fatal("RSA_new failed");
	211	client_host_key->e = BN_new();
	212	client_host_key->n = BN_new();
	213	if (client_host_key->e == NULL \|\| client_host_key->n == NULL)
	214	fatal("BN_new failed");
	215	bits = packet_get_int();
	216	packet_get_bignum(client_host_key->e, &elen);
	217	packet_get_bignum(client_host_key->n, &nlen);
	218
	219	if (bits != BN_num_bits(client_host_key->n))
94ec8c6b	220	verbose("Warning: keysize mismatch for client_host_key: "
0b242b12	221	"actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
a306f2dd	222	packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
	223
	224	authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
	225	RSA_free(client_host_key);
	226
59c97189	227	snprintf(info, sizeof info, " ruser %.100s", client_user);
a306f2dd	228	break;
	229
	230	case SSH_CMSG_AUTH_RSA:
	231	if (!options.rsa_authentication) {
	232	verbose("RSA authentication disabled.");
	233	break;
	234	}
	235	/* RSA authentication requested. */
	236	n = BN_new();
	237	packet_get_bignum(n, &nlen);
	238	packet_integrity_check(plen, nlen, type);
	239	authenticated = auth_rsa(pw, n);
	240	BN_clear_free(n);
	241	break;
	242
	243	case SSH_CMSG_AUTH_PASSWORD:
	244	if (!options.password_authentication) {
	245	verbose("Password authentication disabled.");
	246	break;
	247	}
	248	/*
	249	* Read user password. It is in plain text, but was
	250	* transmitted over the encrypted channel so it is
	251	* not visible to an outside observer.
	252	*/
	253	password = packet_get_string(&dlen);
	254	packet_integrity_check(plen, 4 + dlen, type);
	255
	256	#ifdef USE_PAM
	257	/* Do PAM auth with password */
	258	authenticated = auth_pam_password(pw, password);
4d33e531	259	#elif defined(HAVE_OSF_SIA)
4d33e531	260	/* Do SIA auth with password */
b7ccb051	261	authenticated = auth_sia_password(authctxt->user,
b7ccb051	262	password);
4d33e531	263	#else /* !USE_PAM && !HAVE_OSF_SIA */
b4b5d644	264	/* Try authentication with the password. */
a306f2dd	265	authenticated = auth_password(pw, password);
	266	#endif /* USE_PAM */
	267
	268	memset(password, 0, strlen(password));
	269	xfree(password);
	270	break;
	271
a306f2dd	272	case SSH_CMSG_AUTH_TIS:
a306f2dd	273	debug("rcvd SSH_CMSG_AUTH_TIS");
d464095c	274	if (options.challenge_reponse_authentication == 1) {
59c97189	275	char *challenge = get_challenge(authctxt, authctxt->style);
	276	if (challenge != NULL) {
	277	debug("sending challenge '%s'", challenge);
a306f2dd	278	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
59c97189	279	packet_put_cstring(challenge);
a306f2dd	280	packet_send();
	281	packet_write_wait();
	282	continue;
	283	}
	284	}
	285	break;
	286	case SSH_CMSG_AUTH_TIS_RESPONSE:
	287	debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
d464095c	288	if (options.challenge_reponse_authentication == 1) {
a306f2dd	289	char *response = packet_get_string(&dlen);
59c97189	290	debug("got response '%s'", response);
a306f2dd	291	packet_integrity_check(plen, 4 + dlen, type);
59c97189	292	authenticated = verify_response(authctxt, response);
59c97189	293	memset(response, 'r', dlen);
a306f2dd	294	xfree(response);
	295	}
	296	break;
a306f2dd	297
	298	default:
	299	/*
	300	* Any unknown messages will be ignored (and failure
	301	* returned) during authentication.
	302	*/
	303	log("Unknown message during authentication: type %d", type);
	304	break;
	305	}
59c97189	306	if (!authctxt->valid && authenticated)
	307	fatal("INTERNAL ERROR: authenticated invalid user %s",
	308	authctxt->user);
a306f2dd	309
2b87da3b	310	#ifdef HAVE_CYGWIN
2b87da3b	311	if (authenticated &&
9cd45ea4	312	!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,pw->pw_uid)) {
3c62e7eb	313	packet_disconnect("Authentication rejected for uid %d.",
94ec8c6b	314	(int)pw->pw_uid);
3c62e7eb	315	authenticated = 0;
3c62e7eb	316	}
3c418020	317	#else
59c97189	318	/* Special handling for root */
	319	if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed())
	320	authenticated = 0;
3c418020	321	#endif
2b87da3b	322	#ifdef USE_PAM
94ec8c6b	323	if (authenticated && !do_pam_account(pw->pw_name, client_user))
	324	authenticated = 0;
	325	#endif
a306f2dd	326
59c97189	327	/* Log before sending the reply */
	328	auth_log(authctxt, authenticated, get_authname(type), info);
	329
a306f2dd	330	if (client_user != NULL) {
	331	xfree(client_user);
	332	client_user = NULL;
	333	}
	334
94ec8c6b	335	if (authenticated)
	336	return;
	337
b4b5d644	338	if (authctxt->failures++ > AUTH_FAIL_MAX) {
2b87da3b	339	#ifdef WITH_AIXAUTHENTICATE
	340	loginfailed(authctxt->user,
	341	get_canonical_hostname(options.reverse_mapping_check),
61e96248	342	"ssh");
c1ef8333	343	#endif /* WITH_AIXAUTHENTICATE */
59c97189	344	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
c1ef8333	345	}
a306f2dd	346
a306f2dd	347	packet_start(SSH_SMSG_FAILURE);
	348	packet_send();
	349	packet_write_wait();
	350	}
	351	}
	352
	353	/*
	354	* Performs authentication of an incoming connection. Session key has already
	355	* been exchanged and encryption is enabled.
	356	*/
	357	void
	358	do_authentication()
	359	{
59c97189	360	Authctxt *authctxt;
59c97189	361	struct passwd *pw;
a306f2dd	362	int plen;
1e3b8b07	363	u_int ulen;
59c97189	364	char user, style = NULL;
a306f2dd	365
	366	/* Get the name of the user that we wish to log in as. */
	367	packet_read_expect(&plen, SSH_CMSG_USER);
	368
	369	/* Get the user name. */
	370	user = packet_get_string(&ulen);
	371	packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
	372
59c97189	373	if ((style = strchr(user, ':')) != NULL)
	374	*style++ = 0;
	375
	376	authctxt = authctxt_new();
	377	authctxt->user = user;
	378	authctxt->style = style;
	379
a306f2dd	380	setproctitle("%s", user);
a306f2dd	381
a306f2dd	382	/* Verify that the user is a valid user. */
a306f2dd	383	pw = getpwnam(user);
94ec8c6b	384	if (pw && allowed_user(pw)) {
59c97189	385	authctxt->valid = 1;
59c97189	386	pw = pwcopy(pw);
94ec8c6b	387	} else {
59c97189	388	debug("do_authentication: illegal user %s", user);
94ec8c6b	389	pw = NULL;
94ec8c6b	390	}
59c97189	391	authctxt->pw = pw;
a306f2dd	392
a306f2dd	393	#ifdef USE_PAM
94ec8c6b	394	if (pw)
04fc7a67	395	start_pam(user);
a306f2dd	396	#endif
	397
	398	/*
	399	* If we are not running as root, the user must have the same uid as
94ec8c6b	400	* the server. (Unless you are running Windows)
a306f2dd	401	*/
94ec8c6b	402	#ifndef HAVE_CYGWIN
94ec8c6b	403	if (getuid() != 0 && pw && pw->pw_uid != getuid())
a306f2dd	404	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	405	#endif
a306f2dd	406
59c97189	407	/*
b4b5d644	408	* Loop until the user has been authenticated or the connection is
	409	* closed, do_authloop() returns only if authentication is successful
	410	*/
59c97189	411	do_authloop(authctxt);
a306f2dd	412
a306f2dd	413	/* The user has been authenticated and accepted. */
94ec8c6b	414	packet_start(SSH_SMSG_SUCCESS);
	415	packet_send();
	416	packet_write_wait();
59c97189	417
a306f2dd	418	#ifdef WITH_AIXAUTHENTICATE
c1ef8333	419	/* We don't have a pty yet, so just label the line as "ssh" */
2b87da3b	420	if (loginsuccess(authctxt->user,
61e96248	421	get_canonical_hostname(options.reverse_mapping_check),
61e96248	422	"ssh", &aixloginmsg) < 0)
c1ef8333	423	aixloginmsg = NULL;
a306f2dd	424	#endif /* WITH_AIXAUTHENTICATE */
59c97189	425
	426	xfree(authctxt->user);
	427	xfree(authctxt);
a306f2dd	428
	429	/* Perform session preparation. */
	430	do_authenticated(pw);
	431	}