[openssh.git] / auth1.c

/* $OpenBSD: auth1.c,v 1.66 2006/03/25 13:17:01 djm Exp $ */
/*
 * 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"

#include "xmalloc.h"
#include "rsa.h"
#include "ssh1.h"
#include "packet.h"
#include "buffer.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"
#include "buffer.h"

/* import */
extern ServerOptions options;
extern Buffer loginmsg;

static int auth1_process_password(Authctxt *, char *, size_t);
static int auth1_process_rsa(Authctxt *, char *, size_t);
static int auth1_process_rhosts_rsa(Authctxt *, char *, size_t);
static int auth1_process_tis_challenge(Authctxt *, char *, size_t);
static int auth1_process_tis_response(Authctxt *, char *, size_t);

static char *client_user = NULL;    /* Used to fill in remote user for PAM */

struct AuthMethod1 {
	int type;
	char *name;
	int *enabled;
	int (*method)(Authctxt *, char *, size_t);
};

const struct AuthMethod1 auth1_methods[] = {
	{
		SSH_CMSG_AUTH_PASSWORD, "password",
		&options.password_authentication, auth1_process_password
	},
	{
		SSH_CMSG_AUTH_RSA, "rsa",
		&options.rsa_authentication, auth1_process_rsa
	},
	{
		SSH_CMSG_AUTH_RHOSTS_RSA, "rhosts-rsa",
		&options.rhosts_rsa_authentication, auth1_process_rhosts_rsa
	},
	{
		SSH_CMSG_AUTH_TIS, "challenge-response",
		&options.challenge_response_authentication,
		auth1_process_tis_challenge
	},
	{
		SSH_CMSG_AUTH_TIS_RESPONSE, "challenge-response",
		&options.challenge_response_authentication,
		auth1_process_tis_response
	},
	{ -1, NULL, NULL, NULL}
};

static const struct AuthMethod1
*lookup_authmethod1(int type)
{
	int i;

	for (i = 0; auth1_methods[i].name != NULL; i++)
		if (auth1_methods[i].type == type)
			return (&(auth1_methods[i]));

	return (NULL);
}

static char *
get_authname(int type)
{
	const struct AuthMethod1 *a;
	static char buf[64];

	if ((a = lookup_authmethod1(type)) != NULL)
		return (a->name);
	snprintf(buf, sizeof(buf), "bad-auth-msg-%d", type);
	return (buf);
}

/*ARGSUSED*/
static int
auth1_process_password(Authctxt *authctxt, char *info, size_t infolen)
{
	int authenticated = 0;
	char *password;
	u_int dlen;

	/*
	 * 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, dlen);
	xfree(password);

	return (authenticated);
}

/*ARGSUSED*/
static int
auth1_process_rsa(Authctxt *authctxt, char *info, size_t infolen)
{
	int authenticated = 0;
	BIGNUM *n;

	/* RSA authentication requested. */
	if ((n = BN_new()) == NULL)
		fatal("do_authloop: BN_new failed");
	packet_get_bignum(n);
	packet_check_eom();
	authenticated = auth_rsa(authctxt, n);
	BN_clear_free(n);

	return (authenticated);
}

/*ARGSUSED*/
static int
auth1_process_rhosts_rsa(Authctxt *authctxt, char *info, size_t infolen)
{
	int keybits, authenticated = 0;
	u_int bits;
	Key *client_host_key;
	u_int ulen;

	/*
	 * 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);

	keybits = BN_num_bits(client_host_key->rsa->n);
	if (keybits < 0 || bits != (u_int)keybits) {
		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(authctxt, client_user,
	    client_host_key);
	key_free(client_host_key);

	snprintf(info, infolen, " ruser %.100s", client_user);

	return (authenticated);
}

/*ARGSUSED*/
static int
auth1_process_tis_challenge(Authctxt *authctxt, char *info, size_t infolen)
{
	char *challenge;

	if ((challenge = get_challenge(authctxt)) == NULL)
		return (0);

	debug("sending challenge '%s'", challenge);
	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
	packet_put_cstring(challenge);
	xfree(challenge);
	packet_send();
	packet_write_wait();

	return (-1);
}

/*ARGSUSED*/
static int
auth1_process_tis_response(Authctxt *authctxt, char *info, size_t infolen)
{
	int authenticated = 0;
	char *response;
	u_int dlen;

	response = packet_get_string(&dlen);
	packet_check_eom();
	authenticated = verify_response(authctxt, response);
	memset(response, 'r', dlen);
	xfree(response);

	return (authenticated);
}

/*
 * read packets, try to authenticate the user and
 * return only if authentication is successful
 */
static void
do_authloop(Authctxt *authctxt)
{
	int authenticated = 0;
	char info[1024];
	int prev = 0, type = 0;
	const struct AuthMethod1 *meth;

	debug("Attempting authentication for %s%.100s.",
	    authctxt->valid ? "" : "invalid user ", authctxt->user);

	/* If the user has no password, accept authentication immediately. */
	if (options.password_authentication &&
#ifdef KRB5
	    (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
#endif
	    PRIVSEP(auth_password(authctxt, ""))) {
#ifdef USE_PAM
		if (options.use_pam && (PRIVSEP(do_pam_account())))
#endif
		{
			auth_log(authctxt, 1, "without authentication", "");
			return;
		}
	}

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

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

		info[0] = '\0';

		/* Get a packet from the client. */
		prev = type;
		type = packet_read();

		/*
		 * If we started challenge-response authentication but the
		 * next packet is not a response to our challenge, release
		 * the resources allocated by get_challenge() (which would
		 * normally have been released by verify_response() had we
		 * received such a response)
		 */
		if (prev == SSH_CMSG_AUTH_TIS &&
		    type != SSH_CMSG_AUTH_TIS_RESPONSE)
			abandon_challenge_response(authctxt);

		if ((meth = lookup_authmethod1(type)) == NULL) {
			logit("Unknown message during authentication: "
			    "type %d", type);
			goto skip;
		}

		if (!*(meth->enabled)) {
			verbose("%s authentication disabled.", meth->name);
			goto skip;
		}

		authenticated = meth->method(authctxt, info, sizeof(info));
		if (authenticated == -1)
			continue; /* "postponed" */

#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 (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,
		    authctxt->pw)) {
			packet_disconnect("Authentication rejected for uid %d.",
			    authctxt->pw == NULL ? -1 : authctxt->pw->pw_uid);
			authenticated = 0;
		}
#else
		/* Special handling for root */
		if (authenticated && authctxt->pw->pw_uid == 0 &&
		    !auth_root_allowed(meth->name)) {
 			authenticated = 0;
# ifdef SSH_AUDIT_EVENTS
			PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
# endif
		}
#endif

#ifdef USE_PAM
		if (options.use_pam && authenticated &&
		    !PRIVSEP(do_pam_account())) {
			char *msg;
			size_t len;

			error("Access denied for user %s by PAM account "
			    "configuration", authctxt->user);
			len = buffer_len(&loginmsg);
			buffer_append(&loginmsg, "\0", 1);
			msg = buffer_ptr(&loginmsg);
			/* strip trailing newlines */
			if (len > 0)
				while (len > 0 && msg[--len] == '\n')
					msg[len] = '\0';
			else
				msg = "Access denied.";
			packet_disconnect(msg);
		}
#endif

 skip:
		/* 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++ > options.max_authtries) {
#ifdef SSH_AUDIT_EVENTS
			PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
#endif
			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)
{
	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';

	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: invalid user %s", user);
		authctxt->pw = fakepw();
	}

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

#ifdef USE_PAM
	if (options.use_pam)
		PRIVSEP(start_pam(authctxt));
#endif

	/*
	 * If we are not running as root, the user must have the same uid as
	 * the server.
	 */
#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();
}
Commit	Line	Data
c1cb7bae	1	/* $OpenBSD: auth1.c,v 1.66 2006/03/25 13:17:01 djm Exp $ */
a306f2dd	2	/*
	3	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	4	* All rights reserved
bcbf86ec	5	*
	6	* As far as I am concerned, the code I have written for this software
	7	* can be used freely for any purpose. Any derived versions of this
	8	* software must be clearly marked as such, and if the derived work is
	9	* incompatible with the protocol description in the RFC file, it must be
	10	* called by a name other than "ssh" or "Secure Shell".
a306f2dd	11	*/
	12
	13	#include "includes.h"
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"
42f11eb2	20	#include "log.h"
a306f2dd	21	#include "servconf.h"
	22	#include "compat.h"
	23	#include "auth.h"
7899c98f	24	#include "channels.h"
a306f2dd	25	#include "session.h"
ced49be2	26	#include "uidswap.h"
1853d1ef	27	#include "monitor_wrap.h"
9aab0af7	28	#include "buffer.h"
a306f2dd	29
	30	/* import */
	31	extern ServerOptions options;
9aab0af7	32	extern Buffer loginmsg;
94ec8c6b	33
8485ce56	34	static int auth1_process_password(Authctxt , char , size_t);
	35	static int auth1_process_rsa(Authctxt , char , size_t);
	36	static int auth1_process_rhosts_rsa(Authctxt , char , size_t);
	37	static int auth1_process_tis_challenge(Authctxt , char , size_t);
	38	static int auth1_process_tis_response(Authctxt , char , size_t);
	39
	40	static char client_user = NULL; / Used to fill in remote user for PAM */
	41
	42	struct AuthMethod1 {
	43	int type;
	44	char *name;
	45	int *enabled;
	46	int (method)(Authctxt , char *, size_t);
	47	};
	48
	49	const struct AuthMethod1 auth1_methods[] = {
	50	{
	51	SSH_CMSG_AUTH_PASSWORD, "password",
	52	&options.password_authentication, auth1_process_password
	53	},
	54	{
	55	SSH_CMSG_AUTH_RSA, "rsa",
	56	&options.rsa_authentication, auth1_process_rsa
	57	},
	58	{
	59	SSH_CMSG_AUTH_RHOSTS_RSA, "rhosts-rsa",
	60	&options.rhosts_rsa_authentication, auth1_process_rhosts_rsa
	61	},
	62	{
	63	SSH_CMSG_AUTH_TIS, "challenge-response",
	64	&options.challenge_response_authentication,
	65	auth1_process_tis_challenge
	66	},
	67	{
	68	SSH_CMSG_AUTH_TIS_RESPONSE, "challenge-response",
	69	&options.challenge_response_authentication,
	70	auth1_process_tis_response
	71	},
	72	{ -1, NULL, NULL, NULL}
	73	};
	74
	75	static const struct AuthMethod1
	76	*lookup_authmethod1(int type)
	77	{
	78	int i;
	79
c8e9c167	80	for (i = 0; auth1_methods[i].name != NULL; i++)
8485ce56	81	if (auth1_methods[i].type == type)
	82	return (&(auth1_methods[i]));
	83
	84	return (NULL);
	85	}
	86
396c147e	87	static char *
a306f2dd	88	get_authname(int type)
a306f2dd	89	{
8485ce56	90	const struct AuthMethod1 *a;
	91	static char buf[64];
	92
	93	if ((a = lookup_authmethod1(type)) != NULL)
	94	return (a->name);
	95	snprintf(buf, sizeof(buf), "bad-auth-msg-%d", type);
	96	return (buf);
	97	}
	98
fe8c3af1	99	/ARGSUSED/
8485ce56	100	static int
	101	auth1_process_password(Authctxt authctxt, char info, size_t infolen)
	102	{
	103	int authenticated = 0;
	104	char *password;
	105	u_int dlen;
	106
	107	/*
	108	* Read user password. It is in plain text, but was
	109	* transmitted over the encrypted channel so it is
	110	* not visible to an outside observer.
	111	*/
	112	password = packet_get_string(&dlen);
	113	packet_check_eom();
	114
	115	/* Try authentication with the password. */
	116	authenticated = PRIVSEP(auth_password(authctxt, password));
	117
	118	memset(password, 0, dlen);
	119	xfree(password);
	120
	121	return (authenticated);
	122	}
	123
fe8c3af1	124	/ARGSUSED/
8485ce56	125	static int
	126	auth1_process_rsa(Authctxt authctxt, char info, size_t infolen)
	127	{
	128	int authenticated = 0;
	129	BIGNUM *n;
	130
	131	/* RSA authentication requested. */
	132	if ((n = BN_new()) == NULL)
	133	fatal("do_authloop: BN_new failed");
	134	packet_get_bignum(n);
	135	packet_check_eom();
	136	authenticated = auth_rsa(authctxt, n);
	137	BN_clear_free(n);
	138
	139	return (authenticated);
	140	}
	141
fe8c3af1	142	/ARGSUSED/
8485ce56	143	static int
	144	auth1_process_rhosts_rsa(Authctxt authctxt, char info, size_t infolen)
	145	{
a375df46	146	int keybits, authenticated = 0;
8485ce56	147	u_int bits;
	148	Key *client_host_key;
	149	u_int ulen;
	150
	151	/*
	152	* Get client user name. Note that we just have to
	153	* trust the client; root on the client machine can
	154	* claim to be any user.
	155	*/
	156	client_user = packet_get_string(&ulen);
	157
	158	/* Get the client host key. */
	159	client_host_key = key_new(KEY_RSA1);
	160	bits = packet_get_int();
	161	packet_get_bignum(client_host_key->rsa->e);
	162	packet_get_bignum(client_host_key->rsa->n);
	163
a375df46	164	keybits = BN_num_bits(client_host_key->rsa->n);
a375df46	165	if (keybits < 0 \|\| bits != (u_int)keybits) {
8485ce56	166	verbose("Warning: keysize mismatch for client_host_key: "
	167	"actual %d, announced %d",
	168	BN_num_bits(client_host_key->rsa->n), bits);
a306f2dd	169	}
8485ce56	170	packet_check_eom();
	171
	172	authenticated = auth_rhosts_rsa(authctxt, client_user,
	173	client_host_key);
	174	key_free(client_host_key);
	175
	176	snprintf(info, infolen, " ruser %.100s", client_user);
d1cf9a87	177
8485ce56	178	return (authenticated);
	179	}
	180
fe8c3af1	181	/ARGSUSED/
8485ce56	182	static int
	183	auth1_process_tis_challenge(Authctxt authctxt, char info, size_t infolen)
	184	{
	185	char *challenge;
56964485	186
8485ce56	187	if ((challenge = get_challenge(authctxt)) == NULL)
	188	return (0);
	189
	190	debug("sending challenge '%s'", challenge);
	191	packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
	192	packet_put_cstring(challenge);
	193	xfree(challenge);
	194	packet_send();
	195	packet_write_wait();
	196
	197	return (-1);
	198	}
	199
fe8c3af1	200	/ARGSUSED/
8485ce56	201	static int
	202	auth1_process_tis_response(Authctxt authctxt, char info, size_t infolen)
	203	{
	204	int authenticated = 0;
	205	char *response;
	206	u_int dlen;
	207
	208	response = packet_get_string(&dlen);
	209	packet_check_eom();
	210	authenticated = verify_response(authctxt, response);
	211	memset(response, 'r', dlen);
	212	xfree(response);
	213
	214	return (authenticated);
a306f2dd	215	}
	216
	217	/*
59c97189	218	* read packets, try to authenticate the user and
59c97189	219	* return only if authentication is successful
a306f2dd	220	*/
396c147e	221	static void
59c97189	222	do_authloop(Authctxt *authctxt)
a306f2dd	223	{
94ec8c6b	224	int authenticated = 0;
59c97189	225	char info[1024];
8485ce56	226	int prev = 0, type = 0;
8485ce56	227	const struct AuthMethod1 *meth;
59c97189	228
59c97189	229	debug("Attempting authentication for %s%.100s.",
d77347cc	230	authctxt->valid ? "" : "invalid user ", authctxt->user);
59c97189	231
	232	/* If the user has no password, accept authentication immediately. */
	233	if (options.password_authentication &&
1c590258	234	#ifdef KRB5
59c97189	235	(!options.kerberos_authentication \|\| options.kerberos_or_local_passwd) &&
59c97189	236	#endif
1853d1ef	237	PRIVSEP(auth_password(authctxt, ""))) {
ece30983	238	#ifdef USE_PAM
	239	if (options.use_pam && (PRIVSEP(do_pam_account())))
	240	#endif
	241	{
	242	auth_log(authctxt, 1, "without authentication", "");
	243	return;
	244	}
59c97189	245	}
a306f2dd	246
	247	/* Indicate that authentication is needed. */
	248	packet_start(SSH_SMSG_FAILURE);
	249	packet_send();
	250	packet_write_wait();
	251
59c97189	252	for (;;) {
94ec8c6b	253	/* default to fail */
	254	authenticated = 0;
	255
59c97189	256	info[0] = '\0';
a306f2dd	257
a306f2dd	258	/* Get a packet from the client. */
05114c74	259	prev = type;
54a5250f	260	type = packet_read();
a306f2dd	261
05114c74	262	/*
	263	* If we started challenge-response authentication but the
	264	* next packet is not a response to our challenge, release
	265	* the resources allocated by get_challenge() (which would
	266	* normally have been released by verify_response() had we
	267	* received such a response)
	268	*/
	269	if (prev == SSH_CMSG_AUTH_TIS &&
	270	type != SSH_CMSG_AUTH_TIS_RESPONSE)
	271	abandon_challenge_response(authctxt);
	272
8485ce56	273	if ((meth = lookup_authmethod1(type)) == NULL) {
	274	logit("Unknown message during authentication: "
	275	"type %d", type);
	276	goto skip;
	277	}
	278
	279	if (!*(meth->enabled)) {
	280	verbose("%s authentication disabled.", meth->name);
	281	goto skip;
a306f2dd	282	}
8485ce56	283
	284	authenticated = meth->method(authctxt, info, sizeof(info));
	285	if (authenticated == -1)
	286	continue; /* "postponed" */
	287
af774732	288	#ifdef BSD_AUTH
	289	if (authctxt->as) {
	290	auth_close(authctxt->as);
	291	authctxt->as = NULL;
	292	}
	293	#endif
59c97189	294	if (!authctxt->valid && authenticated)
	295	fatal("INTERNAL ERROR: authenticated invalid user %s",
	296	authctxt->user);
a306f2dd	297
ef51930f	298	#ifdef _UNICOS
ef51930f	299	if (authenticated && cray_access_denied(authctxt->user)) {
	300	authenticated = 0;
	301	fatal("Access denied for user %s.",authctxt->user);
	302	}
	303	#endif /* _UNICOS */
	304
2b87da3b	305	#ifdef HAVE_CYGWIN
2b87da3b	306	if (authenticated &&
d1cf9a87	307	!check_nt_auth(type == SSH_CMSG_AUTH_PASSWORD,
02a57950	308	authctxt->pw)) {
3c62e7eb	309	packet_disconnect("Authentication rejected for uid %d.",
02a57950	310	authctxt->pw == NULL ? -1 : authctxt->pw->pw_uid);
3c62e7eb	311	authenticated = 0;
3c62e7eb	312	}
3c418020	313	#else
59c97189	314	/* Special handling for root */
5d47f1d4	315	if (authenticated && authctxt->pw->pw_uid == 0 &&
8485ce56	316	!auth_root_allowed(meth->name)) {
8485ce56	317	authenticated = 0;
6039eeef	318	# ifdef SSH_AUDIT_EVENTS
6039eeef	319	PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
c00e4d75	320	# endif
c00e4d75	321	}
3c418020	322	#endif
a306f2dd	323
5b9e2464	324	#ifdef USE_PAM
aff51935	325	if (options.use_pam && authenticated &&
9aab0af7	326	!PRIVSEP(do_pam_account())) {
	327	char *msg;
	328	size_t len;
	329
	330	error("Access denied for user %s by PAM account "
98c044d0	331	"configuration", authctxt->user);
9aab0af7	332	len = buffer_len(&loginmsg);
	333	buffer_append(&loginmsg, "\0", 1);
	334	msg = buffer_ptr(&loginmsg);
	335	/* strip trailing newlines */
	336	if (len > 0)
	337	while (len > 0 && msg[--len] == '\n')
	338	msg[len] = '\0';
	339	else
	340	msg = "Access denied.";
	341	packet_disconnect(msg);
	342	}
5b9e2464	343	#endif
5b9e2464	344
8485ce56	345	skip:
59c97189	346	/* Log before sending the reply */
	347	auth_log(authctxt, authenticated, get_authname(type), info);
	348
a306f2dd	349	if (client_user != NULL) {
	350	xfree(client_user);
	351	client_user = NULL;
	352	}
	353
94ec8c6b	354	if (authenticated)
	355	return;
	356
c00e4d75	357	if (authctxt->failures++ > options.max_authtries) {
6039eeef	358	#ifdef SSH_AUDIT_EVENTS
6039eeef	359	PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
c00e4d75	360	#endif
59c97189	361	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
c00e4d75	362	}
a306f2dd	363
a306f2dd	364	packet_start(SSH_SMSG_FAILURE);
	365	packet_send();
	366	packet_write_wait();
	367	}
	368	}
	369
	370	/*
	371	* Performs authentication of an incoming connection. Session key has already
	372	* been exchanged and encryption is enabled.
	373	*/
2362db19	374	void
2362db19	375	do_authentication(Authctxt *authctxt)
a306f2dd	376	{
1e3b8b07	377	u_int ulen;
f8d99a32	378	char user, style = NULL;
a306f2dd	379
a306f2dd	380	/* Get the name of the user that we wish to log in as. */
54a5250f	381	packet_read_expect(SSH_CMSG_USER);
a306f2dd	382
	383	/* Get the user name. */
	384	user = packet_get_string(&ulen);
95500969	385	packet_check_eom();
a306f2dd	386
59c97189	387	if ((style = strchr(user, ':')) != NULL)
ced49be2	388	*style++ = '\0';
59c97189	389
59c97189	390	authctxt->user = user;
	391	authctxt->style = style;
	392
a306f2dd	393	/* Verify that the user is a valid user. */
5f1f36b5	394	if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL)
59c97189	395	authctxt->valid = 1;
96d0bf74	396	else {
d77347cc	397	debug("do_authentication: invalid user %s", user);
96d0bf74	398	authctxt->pw = fakepw();
96d0bf74	399	}
a306f2dd	400
bd5c0694	401	setproctitle("%s%s", authctxt->valid ? user : "unknown",
1853d1ef	402	use_privsep ? " [net]" : "");
6172e290	403
a306f2dd	404	#ifdef USE_PAM
7fceb20d	405	if (options.use_pam)
529d73ab	406	PRIVSEP(start_pam(authctxt));
a306f2dd	407	#endif
	408
	409	/*
	410	* If we are not running as root, the user must have the same uid as
8485ce56	411	* the server.
a306f2dd	412	*/
94ec8c6b	413	#ifndef HAVE_CYGWIN
5f1f36b5	414	if (!use_privsep && getuid() != 0 && authctxt->pw &&
5f1f36b5	415	authctxt->pw->pw_uid != getuid())
a306f2dd	416	packet_disconnect("Cannot change user when server not running as root.");
3c62e7eb	417	#endif
a306f2dd	418
59c97189	419	/*
b4b5d644	420	* Loop until the user has been authenticated or the connection is
	421	* closed, do_authloop() returns only if authentication is successful
	422	*/
59c97189	423	do_authloop(authctxt);
a306f2dd	424
a306f2dd	425	/* The user has been authenticated and accepted. */
94ec8c6b	426	packet_start(SSH_SMSG_SUCCESS);
	427	packet_send();
	428	packet_write_wait();
a306f2dd	429	}