[gssapi-openssh.git] / openssh / auth2.c

/* $OpenBSD: auth2.c,v 1.119 2008/07/04 23:30:16 djm Exp $ */
/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/uio.h>

#include <fcntl.h>
#include <pwd.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>

#include "xmalloc.h"
#include "atomicio.h"
#include "ssh2.h"
#include "packet.h"
#include "log.h"
#include "buffer.h"
#include "servconf.h"
#include "compat.h"
#include "key.h"
#include "hostfile.h"
#include "auth.h"
#include "dispatch.h"
#include "pathnames.h"
#include "buffer.h"
#include "canohost.h"

#ifdef GSSAPI
#include "ssh-gss.h"
#endif
#include "monitor_wrap.h"

/* import */
extern ServerOptions options;
extern u_char *session_id2;
extern u_int session_id2_len;
extern Buffer loginmsg;

/* methods */

extern Authmethod method_none;
extern Authmethod method_pubkey;
extern Authmethod method_passwd;
extern Authmethod method_kbdint;
extern Authmethod method_hostbased;
#ifdef GSSAPI
extern Authmethod method_external;
extern Authmethod method_gsskeyex;
extern Authmethod method_gssapi;
extern Authmethod method_gssapi_compat;
#endif

static int log_flag = 0;


Authmethod *authmethods[] = {
	&method_none,
	&method_pubkey,
#ifdef GSSAPI
	&method_gsskeyex,
	&method_external,
	&method_gssapi,
	&method_gssapi_compat,
#endif
	&method_passwd,
	&method_kbdint,
	&method_hostbased,
	NULL
};

/* protocol */

static void input_service_request(int, u_int32_t, void *);
static void input_userauth_request(int, u_int32_t, void *);

/* helper */
static Authmethod *authmethod_lookup(const char *);
static char *authmethods_get(void);

char *
auth2_read_banner(void)
{
	struct stat st;
	char *banner = NULL;
	size_t len, n;
	int fd;

	if ((fd = open(options.banner, O_RDONLY)) == -1)
		return (NULL);
	if (fstat(fd, &st) == -1) {
		close(fd);
		return (NULL);
	}
	if (st.st_size > 1*1024*1024) {
		close(fd);
		return (NULL);
	}

	len = (size_t)st.st_size;		/* truncate */
	banner = xmalloc(len + 1);
	n = atomicio(read, fd, banner, len);
	close(fd);

	if (n != len) {
		xfree(banner);
		return (NULL);
	}
	banner[n] = '\0';

	return (banner);
}

void
userauth_send_banner(const char *msg)
{
	if (datafellows & SSH_BUG_BANNER)
		return;

	packet_start(SSH2_MSG_USERAUTH_BANNER);
	packet_put_cstring(msg);
	packet_put_cstring("");		/* language, unused */
	packet_send();
	debug("%s: sent", __func__);
}

static void
userauth_banner(void)
{
	char *banner = NULL;

	if (options.banner == NULL ||
	    strcasecmp(options.banner, "none") == 0 ||
	    (datafellows & SSH_BUG_BANNER) != 0)
		return;

	if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
		goto done;
	userauth_send_banner(banner);

done:
	if (banner)
		xfree(banner);
}

/*
 * loop until authctxt->success == TRUE
 */
void
do_authentication2(Authctxt *authctxt)
{
	dispatch_init(&dispatch_protocol_error);
	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
	dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
}

/*ARGSUSED*/
static void
input_service_request(int type, u_int32_t seq, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	u_int len;
	int acceptit = 0;
	char *service = packet_get_string(&len);
	packet_check_eom();

	if (authctxt == NULL)
		fatal("input_service_request: no authctxt");

	if (strcmp(service, "ssh-userauth") == 0) {
		if (!authctxt->success) {
			acceptit = 1;
			/* now we can handle user-auth requests */
			dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
		}
	}
	/* XXX all other service requests are denied */

	if (acceptit) {
		packet_start(SSH2_MSG_SERVICE_ACCEPT);
		packet_put_cstring(service);
		packet_send();
		packet_write_wait();
	} else {
		debug("bad service request %s", service);
		packet_disconnect("bad service request %s", service);
	}
	xfree(service);
}

/*ARGSUSED*/
static void
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
	Authctxt *authctxt = ctxt;
	Authmethod *m = NULL;
	char *user, *service, *method, *style = NULL;
	int authenticated = 0;

	if (authctxt == NULL)
		fatal("input_userauth_request: no authctxt");

	user = packet_get_string(NULL);
	service = packet_get_string(NULL);
	method = packet_get_string(NULL);

#ifdef GSSAPI
	if (user[0] == '\0') {
	    debug("received empty username for %s", method);
	    if (strcmp(method, "external-keyx") == 0 ||
		strcmp(method, "gssapi-keyex") == 0) {
		char *lname = NULL;
		PRIVSEP(ssh_gssapi_localname(&lname));
		if (lname && lname[0] != '\0') {
		    xfree(user);
		    user = lname;
		    debug("set username to %s from gssapi context", user);
		} else {
		    debug("failed to set username from gssapi context");
		    packet_send_debug("failed to set username from gssapi context");
		}
	    }
	}
#endif

	debug("userauth-request for user %s service %s method %s",
	      user[0] ? user : "<implicit>", service, method);
	if (!log_flag) {
		logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s", 
		      get_remote_ipaddr(), get_remote_port(),
              user[0] ? user : "<implicit>");
		log_flag = 1;
	}
	debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);

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

	/* If first time or username changed or empty username,
	   setup/reset authentication context. */
	if ((authctxt->attempt++ == 0) ||
	    (strcmp(user, authctxt->user) != 0) ||
	    (strcmp(user, "") == 0)) {
		if (authctxt->user) {
		    xfree(authctxt->user);
		    authctxt->user = NULL;
		}
		authctxt->valid = 0;
        authctxt->user = xstrdup(user);
        if (strcmp(service, "ssh-connection") != 0) {
            packet_disconnect("Unsupported service %s", service);
        }
#ifdef GSSAPI
		/* If we're going to set the username based on the
		   GSSAPI context later, then wait until then to
		   verify it. Just put in placeholders for now. */
		if ((strcmp(user, "") == 0) &&
		    ((strcmp(method, "gssapi") == 0) ||
		     (strcmp(method, "gssapi-with-mic") == 0))) {
			authctxt->pw = fakepw();
		} else {
#endif
		authctxt->pw = PRIVSEP(getpwnamallow(user));
		if (authctxt->pw) {
			authctxt->valid = 1;
			debug2("input_userauth_request: setting up authctxt for %s", user);
		} else {
			logit("input_userauth_request: invalid user %s", user);
			authctxt->pw = fakepw();
#ifdef SSH_AUDIT_EVENTS
			PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
		}
#ifdef GSSAPI
		} /* endif for setting username based on GSSAPI context */
#endif
#ifdef USE_PAM
		if (options.use_pam)
			PRIVSEP(start_pam(authctxt));
#endif
		setproctitle("%s%s", authctxt->valid ? user : "unknown",
		    use_privsep ? " [net]" : "");
		if (authctxt->attempt == 1) {
            authctxt->service = xstrdup(service);
            authctxt->style = style ? xstrdup(style) : NULL;
            if (use_privsep)
                mm_inform_authserv(service, style);
            userauth_banner();
		}
	}
	if (strcmp(service, authctxt->service) != 0) {
		packet_disconnect("Change of service not allowed: "
		    "(%s,%s) -> (%s,%s)",
		    authctxt->user, authctxt->service, user, service);
	}
	/* reset state */
	auth2_challenge_stop(authctxt);

#ifdef GSSAPI
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif

	authctxt->postponed = 0;
	authctxt->server_caused_failure = 0;

	/* try to authenticate user */
	m = authmethod_lookup(method);
	if (m != NULL && authctxt->failures < options.max_authtries) {
		debug2("input_userauth_request: try method %s", method);
		authenticated =	m->userauth(authctxt);
	}
	userauth_finish(authctxt, authenticated, method);

	xfree(service);
	xfree(user);
	xfree(method);
}

void
userauth_finish(Authctxt *authctxt, int authenticated, char *method)
{
	char *methods;

	if (!authctxt->valid && authenticated)
		fatal("INTERNAL ERROR: authenticated invalid user %s",
		    authctxt->user);

	/* Special handling for root */
	if (authenticated && authctxt->pw->pw_uid == 0 &&
	    !auth_root_allowed(method)) {
		authenticated = 0;
#ifdef SSH_AUDIT_EVENTS
		PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
#endif
	}

#ifdef USE_PAM
	if (options.use_pam && authenticated) {
		if (!PRIVSEP(do_pam_account())) {
			/* if PAM returned a message, send it to the user */
			if (buffer_len(&loginmsg) > 0) {
				buffer_append(&loginmsg, "\0", 1);
				userauth_send_banner(buffer_ptr(&loginmsg));
				packet_write_wait();
			}
			fatal("Access denied for user %s by PAM account "
			    "configuration", authctxt->user);
		}
	}
#endif

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

	/* Log before sending the reply */
	auth_log(authctxt, authenticated, method, " ssh2");

	if (authctxt->postponed)
		return;

	/* XXX todo: check if multiple auth methods are needed */
	if (authenticated == 1) {
		/* turn off userauth */
		dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
		packet_start(SSH2_MSG_USERAUTH_SUCCESS);
		packet_send();
		packet_write_wait();
		/* now we can break out */
		authctxt->success = 1;
	} else {
		/* Dont count server configuration issues against the client */
		/* Allow initial try of "none" auth without failure penalty */
		if (!authctxt->server_caused_failure &&
            (authctxt->attempt > 1 || strcmp(method, "none") != 0))
			authctxt->failures++;
		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);
		}
		methods = authmethods_get();
		packet_start(SSH2_MSG_USERAUTH_FAILURE);
		packet_put_cstring(methods);
		packet_put_char(0);	/* XXX partial success, unused */
		packet_send();
		packet_write_wait();
		xfree(methods);
	}
}

static char *
authmethods_get(void)
{
	Buffer b;
	char *list;
	int i;

	buffer_init(&b);
	for (i = 0; authmethods[i] != NULL; i++) {
		if (strcmp(authmethods[i]->name, "none") == 0)
			continue;
		if (authmethods[i]->enabled != NULL &&
		    *(authmethods[i]->enabled) != 0) {
			if (buffer_len(&b) > 0)
				buffer_append(&b, ",", 1);
			buffer_append(&b, authmethods[i]->name,
			    strlen(authmethods[i]->name));
		}
	}
	buffer_append(&b, "\0", 1);
	list = xstrdup(buffer_ptr(&b));
	buffer_free(&b);
	return list;
}

static Authmethod *
authmethod_lookup(const char *name)
{
	int i;

	if (name != NULL)
		for (i = 0; authmethods[i] != NULL; i++)
			if (authmethods[i]->enabled != NULL &&
			    *(authmethods[i]->enabled) != 0 &&
			    strcmp(name, authmethods[i]->name) == 0)
				return authmethods[i];
	debug2("Unrecognized authentication method name: %s",
	    name ? name : "NULL");
	return NULL;
}
Commit	Line	Data
5156b1a1	1	/* $OpenBSD: auth2.c,v 1.119 2008/07/04 23:30:16 djm Exp $ */
3c0ef626	2	/*
	3	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	15	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	16	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	17	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	18	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	19	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	20	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	21	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	22	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	23	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	24	*/
	25
	26	#include "includes.h"
3c0ef626	27
30460aeb	28	#include <sys/types.h>
5156b1a1	29	#include <sys/stat.h>
5156b1a1	30	#include <sys/uio.h>
30460aeb	31
5156b1a1	32	#include <fcntl.h>
30460aeb	33	#include <pwd.h>
	34	#include <stdarg.h>
	35	#include <string.h>
5156b1a1	36	#include <unistd.h>
30460aeb	37
3c0ef626	38	#include "xmalloc.h"
5156b1a1	39	#include "atomicio.h"
30460aeb	40	#include "ssh2.h"
3c0ef626	41	#include "packet.h"
3c0ef626	42	#include "log.h"
30460aeb	43	#include "buffer.h"
3c0ef626	44	#include "servconf.h"
bddc9ab0	45	#include "compat.h"
30460aeb	46	#include "key.h"
30460aeb	47	#include "hostfile.h"
3c0ef626	48	#include "auth.h"
3c0ef626	49	#include "dispatch.h"
3c0ef626	50	#include "pathnames.h"
dfddba3d	51	#include "buffer.h"
fa7499cc	52	#include "canohost.h"
3c0ef626	53
5598e598	54	#ifdef GSSAPI
	55	#include "ssh-gss.h"
	56	#endif
30460aeb	57	#include "monitor_wrap.h"
5598e598	58
3c0ef626	59	/* import */
	60	extern ServerOptions options;
	61	extern u_char *session_id2;
7cac2b65	62	extern u_int session_id2_len;
dfddba3d	63	extern Buffer loginmsg;
3c0ef626	64
44a053a3	65	/* methods */
	66
	67	extern Authmethod method_none;
44a053a3	68	extern Authmethod method_pubkey;
	69	extern Authmethod method_passwd;
	70	extern Authmethod method_kbdint;
	71	extern Authmethod method_hostbased;
db870295	72	#ifdef GSSAPI
db870295	73	extern Authmethod method_external;
fe4ad273	74	extern Authmethod method_gsskeyex;
db870295	75	extern Authmethod method_gssapi;
540d72c3	76	extern Authmethod method_gssapi_compat;
db870295	77	#endif
44a053a3	78
fa7499cc	79	static int log_flag = 0;
	80
	81
44a053a3	82	Authmethod *authmethods[] = {
44a053a3	83	&method_none,
44a053a3	84	&method_pubkey,
7cac2b65	85	#ifdef GSSAPI
fe4ad273	86	&method_gsskeyex,
540d72c3	87	&method_external,
7cac2b65	88	&method_gssapi,
540d72c3	89	&method_gssapi_compat,
7cac2b65	90	#endif
44a053a3	91	&method_passwd,
	92	&method_kbdint,
	93	&method_hostbased,
	94	NULL
3c0ef626	95	};
	96
	97	/* protocol */
	98
1e608e42	99	static void input_service_request(int, u_int32_t, void *);
1e608e42	100	static void input_userauth_request(int, u_int32_t, void *);
3c0ef626	101
	102	/* helper */
	103	static Authmethod authmethod_lookup(const char );
	104	static char *authmethods_get(void);
3c0ef626	105
5156b1a1	106	char *
	107	auth2_read_banner(void)
	108	{
	109	struct stat st;
	110	char *banner = NULL;
	111	size_t len, n;
	112	int fd;
	113
	114	if ((fd = open(options.banner, O_RDONLY)) == -1)
	115	return (NULL);
	116	if (fstat(fd, &st) == -1) {
	117	close(fd);
	118	return (NULL);
	119	}
	120	if (st.st_size > 110241024) {
	121	close(fd);
	122	return (NULL);
	123	}
	124
	125	len = (size_t)st.st_size; /* truncate */
	126	banner = xmalloc(len + 1);
	127	n = atomicio(read, fd, banner, len);
	128	close(fd);
	129
	130	if (n != len) {
	131	xfree(banner);
	132	return (NULL);
	133	}
	134	banner[n] = '\0';
	135
	136	return (banner);
	137	}
	138
	139	void
	140	userauth_send_banner(const char *msg)
	141	{
	142	if (datafellows & SSH_BUG_BANNER)
	143	return;
	144
	145	packet_start(SSH2_MSG_USERAUTH_BANNER);
	146	packet_put_cstring(msg);
	147	packet_put_cstring(""); /* language, unused */
	148	packet_send();
	149	debug("%s: sent", __func__);
	150	}
	151
	152	static void
	153	userauth_banner(void)
	154	{
	155	char *banner = NULL;
	156
	157	if (options.banner == NULL \|\|
	158	strcasecmp(options.banner, "none") == 0 \|\|
	159	(datafellows & SSH_BUG_BANNER) != 0)
	160	return;
	161
	162	if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
	163	goto done;
	164	userauth_send_banner(banner);
	165
	166	done:
	167	if (banner)
	168	xfree(banner);
	169	}
170
3c0ef626	171	/*
	172	* loop until authctxt->success == TRUE
	173	*/
540d72c3	174	void
540d72c3	175	do_authentication2(Authctxt *authctxt)
3c0ef626	176	{
1e608e42	177	dispatch_init(&dispatch_protocol_error);
3c0ef626	178	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
3c0ef626	179	dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
3c0ef626	180	}
3c0ef626	181
30460aeb	182	/ARGSUSED/
3c0ef626	183	static void
1e608e42	184	input_service_request(int type, u_int32_t seq, void *ctxt)
3c0ef626	185	{
	186	Authctxt *authctxt = ctxt;
	187	u_int len;
d03f4262	188	int acceptit = 0;
3c0ef626	189	char *service = packet_get_string(&len);
1e608e42	190	packet_check_eom();
3c0ef626	191
	192	if (authctxt == NULL)
	193	fatal("input_service_request: no authctxt");
	194
	195	if (strcmp(service, "ssh-userauth") == 0) {
	196	if (!authctxt->success) {
d03f4262	197	acceptit = 1;
3c0ef626	198	/* now we can handle user-auth requests */
	199	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
	200	}
	201	}
	202	/* XXX all other service requests are denied */
	203
d03f4262	204	if (acceptit) {
3c0ef626	205	packet_start(SSH2_MSG_SERVICE_ACCEPT);
	206	packet_put_cstring(service);
	207	packet_send();
	208	packet_write_wait();
	209	} else {
	210	debug("bad service request %s", service);
	211	packet_disconnect("bad service request %s", service);
	212	}
	213	xfree(service);
	214	}
	215
30460aeb	216	/ARGSUSED/
3c0ef626	217	static void
1e608e42	218	input_userauth_request(int type, u_int32_t seq, void *ctxt)
3c0ef626	219	{
	220	Authctxt *authctxt = ctxt;
	221	Authmethod *m = NULL;
	222	char user, service, method, style = NULL;
	223	int authenticated = 0;
	224
	225	if (authctxt == NULL)
	226	fatal("input_userauth_request: no authctxt");
	227
	228	user = packet_get_string(NULL);
	229	service = packet_get_string(NULL);
	230	method = packet_get_string(NULL);
73a68d83	231
305d07c0	232	#ifdef GSSAPI
8f3eb4db	233	if (user[0] == '\0') {
b8e8844a	234	debug("received empty username for %s", method);
fe4ad273	235	if (strcmp(method, "external-keyx") == 0 \|\|
fe4ad273	236	strcmp(method, "gssapi-keyex") == 0) {
b8e8844a	237	char *lname = NULL;
	238	PRIVSEP(ssh_gssapi_localname(&lname));
	239	if (lname && lname[0] != '\0') {
	240	xfree(user);
	241	user = lname;
	242	debug("set username to %s from gssapi context", user);
9ec9d5ad	243	} else {
b8e8844a	244	debug("failed to set username from gssapi context");
d9e17760	245	packet_send_debug("failed to set username from gssapi context");
b8e8844a	246	}
b59afbfe	247	}
	248	}
	249	#endif
73a68d83	250
b8e8844a	251	debug("userauth-request for user %s service %s method %s",
8f3eb4db	252	user[0] ? user : "<implicit>", service, method);
fa7499cc	253	if (!log_flag) {
fa7499cc	254	logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s",
d3057ca4	255	get_remote_ipaddr(), get_remote_port(),
d3057ca4	256	user[0] ? user : "<implicit>");
fa7499cc	257	log_flag = 1;
fa7499cc	258	}
3c0ef626	259	debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
	260
	261	if ((style = strchr(user, ':')) != NULL)
	262	*style++ = 0;
	263
86a22a0a	264	/* If first time or username changed or empty username,
781f72b9	265	setup/reset authentication context. */
	266	if ((authctxt->attempt++ == 0) \|\|
	267	(strcmp(user, authctxt->user) != 0) \|\|
	268	(strcmp(user, "") == 0)) {
b59afbfe	269	if (authctxt->user) {
	270	xfree(authctxt->user);
	271	authctxt->user = NULL;
	272	}
b809a58e	273	authctxt->valid = 0;
86a22a0a	274	authctxt->user = xstrdup(user);
	275	if (strcmp(service, "ssh-connection") != 0) {
	276	packet_disconnect("Unsupported service %s", service);
	277	}
b8e8844a	278	#ifdef GSSAPI
9ec9d5ad	279	/* If we're going to set the username based on the
9ec9d5ad	280	GSSAPI context later, then wait until then to
8f3eb4db	281	verify it. Just put in placeholders for now. */
	282	if ((strcmp(user, "") == 0) &&
	283	((strcmp(method, "gssapi") == 0) \|\|
	284	(strcmp(method, "gssapi-with-mic") == 0))) {
	285	authctxt->pw = fakepw();
8f3eb4db	286	} else {
b8e8844a	287	#endif
510132b6	288	authctxt->pw = PRIVSEP(getpwnamallow(user));
86a22a0a	289	if (authctxt->pw) {
3c0ef626	290	authctxt->valid = 1;
3c0ef626	291	debug2("input_userauth_request: setting up authctxt for %s", user);
3c0ef626	292	} else {
7e82606e	293	logit("input_userauth_request: invalid user %s", user);
7cac2b65	294	authctxt->pw = fakepw();
dfddba3d	295	#ifdef SSH_AUDIT_EVENTS
dfddba3d	296	PRIVSEP(audit_event(SSH_INVALID_USER));
3c0ef626	297	#endif
3c0ef626	298	}
b8e8844a	299	#ifdef GSSAPI
9ec9d5ad	300	} /* endif for setting username based on GSSAPI context */
08822d99	301	#endif
	302	#ifdef USE_PAM
	303	if (options.use_pam)
	304	PRIVSEP(start_pam(authctxt));
b8e8844a	305	#endif
7e82606e	306	setproctitle("%s%s", authctxt->valid ? user : "unknown",
510132b6	307	use_privsep ? " [net]" : "");
88ca8dfd	308	if (authctxt->attempt == 1) {
86a22a0a	309	authctxt->service = xstrdup(service);
	310	authctxt->style = style ? xstrdup(style) : NULL;
	311	if (use_privsep)
	312	mm_inform_authserv(service, style);
5156b1a1	313	userauth_banner();
86a22a0a	314	}
885ffc2b	315	}
885ffc2b	316	if (strcmp(service, authctxt->service) != 0) {
67b84e65	317	packet_disconnect("Change of service not allowed: "
	318	"(%s,%s) -> (%s,%s)",
	319	authctxt->user, authctxt->service, user, service);
3c0ef626	320	}
3c0ef626	321	/* reset state */
1e608e42	322	auth2_challenge_stop(authctxt);
5598e598	323
5598e598	324	#ifdef GSSAPI
1e608e42	325	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
1e608e42	326	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
5598e598	327	#endif
5598e598	328
3c0ef626	329	authctxt->postponed = 0;
fe4ad273	330	authctxt->server_caused_failure = 0;
3c0ef626	331
	332	/* try to authenticate user */
	333	m = authmethod_lookup(method);
5156b1a1	334	if (m != NULL && authctxt->failures < options.max_authtries) {
3c0ef626	335	debug2("input_userauth_request: try method %s", method);
	336	authenticated = m->userauth(authctxt);
	337	}
	338	userauth_finish(authctxt, authenticated, method);
	339
	340	xfree(service);
	341	xfree(user);
	342	xfree(method);
	343	}
	344
	345	void
	346	userauth_finish(Authctxt authctxt, int authenticated, char method)
	347	{
	348	char *methods;
	349
	350	if (!authctxt->valid && authenticated)
	351	fatal("INTERNAL ERROR: authenticated invalid user %s",
	352	authctxt->user);
	353
	354	/* Special handling for root */
bfe49944	355	if (authenticated && authctxt->pw->pw_uid == 0 &&
dfddba3d	356	!auth_root_allowed(method)) {
3c0ef626	357	authenticated = 0;
dfddba3d	358	#ifdef SSH_AUDIT_EVENTS
	359	PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
	360	#endif
	361	}
3c0ef626	362
3c0ef626	363	#ifdef USE_PAM
dfddba3d	364	if (options.use_pam && authenticated) {
	365	if (!PRIVSEP(do_pam_account())) {
	366	/* if PAM returned a message, send it to the user */
	367	if (buffer_len(&loginmsg) > 0) {
	368	buffer_append(&loginmsg, "\0", 1);
	369	userauth_send_banner(buffer_ptr(&loginmsg));
	370	packet_write_wait();
	371	}
	372	fatal("Access denied for user %s by PAM account "
2ce0bfe4	373	"configuration", authctxt->user);
dfddba3d	374	}
dfddba3d	375	}
7cac2b65	376	#endif
3c0ef626	377
d03f4262	378	#ifdef _UNICOS
	379	if (authenticated && cray_access_denied(authctxt->user)) {
	380	authenticated = 0;
	381	fatal("Access denied for user %s.",authctxt->user);
	382	}
	383	#endif /* _UNICOS */
	384
3c0ef626	385	/* Log before sending the reply */
	386	auth_log(authctxt, authenticated, method, " ssh2");
	387
	388	if (authctxt->postponed)
	389	return;
	390
	391	/* XXX todo: check if multiple auth methods are needed */
	392	if (authenticated == 1) {
	393	/* turn off userauth */
1e608e42	394	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
3c0ef626	395	packet_start(SSH2_MSG_USERAUTH_SUCCESS);
	396	packet_send();
	397	packet_write_wait();
	398	/* now we can break out */
	399	authctxt->success = 1;
	400	} else {
fe4ad273	401	/* Dont count server configuration issues against the client */
5156b1a1	402	/* Allow initial try of "none" auth without failure penalty */
	403	if (!authctxt->server_caused_failure &&
	404	(authctxt->attempt > 1 \|\| strcmp(method, "none") != 0))
	405	authctxt->failures++;
	406	if (authctxt->failures >= options.max_authtries) {
dfddba3d	407	#ifdef SSH_AUDIT_EVENTS
	408	PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
	409	#endif
3c0ef626	410	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
dfddba3d	411	}
3c0ef626	412	methods = authmethods_get();
	413	packet_start(SSH2_MSG_USERAUTH_FAILURE);
	414	packet_put_cstring(methods);
	415	packet_put_char(0); /* XXX partial success, unused */
	416	packet_send();
	417	packet_write_wait();
	418	xfree(methods);
	419	}
	420	}
	421
3c0ef626	422	static char *
	423	authmethods_get(void)
	424	{
1e608e42	425	Buffer b;
3c0ef626	426	char *list;
44a053a3	427	int i;
3c0ef626	428
1e608e42	429	buffer_init(&b);
44a053a3	430	for (i = 0; authmethods[i] != NULL; i++) {
44a053a3	431	if (strcmp(authmethods[i]->name, "none") == 0)
3c0ef626	432	continue;
44a053a3	433	if (authmethods[i]->enabled != NULL &&
44a053a3	434	*(authmethods[i]->enabled) != 0) {
1e608e42	435	if (buffer_len(&b) > 0)
1e608e42	436	buffer_append(&b, ",", 1);
44a053a3	437	buffer_append(&b, authmethods[i]->name,
44a053a3	438	strlen(authmethods[i]->name));
3c0ef626	439	}
3c0ef626	440	}
1e608e42	441	buffer_append(&b, "\0", 1);
	442	list = xstrdup(buffer_ptr(&b));
	443	buffer_free(&b);
3c0ef626	444	return list;
	445	}
	446
	447	static Authmethod *
	448	authmethod_lookup(const char *name)
	449	{
44a053a3	450	int i;
44a053a3	451
3c0ef626	452	if (name != NULL)
44a053a3	453	for (i = 0; authmethods[i] != NULL; i++)
	454	if (authmethods[i]->enabled != NULL &&
	455	*(authmethods[i]->enabled) != 0 &&
	456	strcmp(name, authmethods[i]->name) == 0)
	457	return authmethods[i];
	458	debug2("Unrecognized authentication method name: %s",
	459	name ? name : "NULL");
3c0ef626	460	return NULL;
3c0ef626	461	}
5156b1a1	462