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

/* $OpenBSD: auth2.c,v 1.121 2009/06/22 05:39:28 dtucker 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 "atomicio.h"
#include "xmalloc.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
#ifdef JPAKE
extern Authmethod method_jpake;
#endif

static int log_flag = 0;


Authmethod *authmethods[] = {
	&method_none,
	&method_pubkey,
#ifdef GSSAPI
	&method_gsskeyex,
	&method_external,
	&method_gssapi,
	&method_gssapi_compat,
#endif
#ifdef JPAKE
	&method_jpake,
#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 JPAKE
	auth2_jpake_stop(authctxt);
#endif

#ifdef GSSAPI
	/* XXX move to auth2_gssapi_stop() */
	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
b5afdff5	1	/* $OpenBSD: auth2.c,v 1.121 2009/06/22 05:39:28 dtucker 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
5156b1a1	38	#include "atomicio.h"
b5afdff5	39	#include "xmalloc.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
5262cbfb	78	#ifdef JPAKE
	79	extern Authmethod method_jpake;
	80	#endif
44a053a3	81
fa7499cc	82	static int log_flag = 0;
	83
	84
44a053a3	85	Authmethod *authmethods[] = {
44a053a3	86	&method_none,
44a053a3	87	&method_pubkey,
7cac2b65	88	#ifdef GSSAPI
fe4ad273	89	&method_gsskeyex,
540d72c3	90	&method_external,
7cac2b65	91	&method_gssapi,
540d72c3	92	&method_gssapi_compat,
5262cbfb	93	#endif
	94	#ifdef JPAKE
	95	&method_jpake,
7cac2b65	96	#endif
44a053a3	97	&method_passwd,
	98	&method_kbdint,
	99	&method_hostbased,
	100	NULL
3c0ef626	101	};
	102
	103	/* protocol */
	104
1e608e42	105	static void input_service_request(int, u_int32_t, void *);
1e608e42	106	static void input_userauth_request(int, u_int32_t, void *);
3c0ef626	107
	108	/* helper */
	109	static Authmethod authmethod_lookup(const char );
	110	static char *authmethods_get(void);
3c0ef626	111
5156b1a1	112	char *
	113	auth2_read_banner(void)
	114	{
	115	struct stat st;
	116	char *banner = NULL;
	117	size_t len, n;
	118	int fd;
	119
	120	if ((fd = open(options.banner, O_RDONLY)) == -1)
	121	return (NULL);
	122	if (fstat(fd, &st) == -1) {
	123	close(fd);
	124	return (NULL);
	125	}
	126	if (st.st_size > 110241024) {
	127	close(fd);
	128	return (NULL);
	129	}
	130
	131	len = (size_t)st.st_size; /* truncate */
	132	banner = xmalloc(len + 1);
	133	n = atomicio(read, fd, banner, len);
	134	close(fd);
	135
	136	if (n != len) {
	137	xfree(banner);
	138	return (NULL);
	139	}
	140	banner[n] = '\0';
	141
	142	return (banner);
	143	}
	144
	145	void
	146	userauth_send_banner(const char *msg)
	147	{
	148	if (datafellows & SSH_BUG_BANNER)
	149	return;
	150
	151	packet_start(SSH2_MSG_USERAUTH_BANNER);
	152	packet_put_cstring(msg);
	153	packet_put_cstring(""); /* language, unused */
	154	packet_send();
	155	debug("%s: sent", __func__);
	156	}
	157
	158	static void
	159	userauth_banner(void)
	160	{
	161	char *banner = NULL;
	162
	163	if (options.banner == NULL \|\|
	164	strcasecmp(options.banner, "none") == 0 \|\|
	165	(datafellows & SSH_BUG_BANNER) != 0)
	166	return;
	167
	168	if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
	169	goto done;
	170	userauth_send_banner(banner);
	171
	172	done:
	173	if (banner)
	174	xfree(banner);
	175	}
176
3c0ef626	177	/*
	178	* loop until authctxt->success == TRUE
	179	*/
540d72c3	180	void
540d72c3	181	do_authentication2(Authctxt *authctxt)
3c0ef626	182	{
1e608e42	183	dispatch_init(&dispatch_protocol_error);
3c0ef626	184	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
3c0ef626	185	dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
3c0ef626	186	}
3c0ef626	187
30460aeb	188	/ARGSUSED/
3c0ef626	189	static void
1e608e42	190	input_service_request(int type, u_int32_t seq, void *ctxt)
3c0ef626	191	{
	192	Authctxt *authctxt = ctxt;
	193	u_int len;
d03f4262	194	int acceptit = 0;
3c0ef626	195	char *service = packet_get_string(&len);
1e608e42	196	packet_check_eom();
3c0ef626	197
	198	if (authctxt == NULL)
	199	fatal("input_service_request: no authctxt");
	200
	201	if (strcmp(service, "ssh-userauth") == 0) {
	202	if (!authctxt->success) {
d03f4262	203	acceptit = 1;
3c0ef626	204	/* now we can handle user-auth requests */
	205	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
	206	}
	207	}
	208	/* XXX all other service requests are denied */
	209
d03f4262	210	if (acceptit) {
3c0ef626	211	packet_start(SSH2_MSG_SERVICE_ACCEPT);
	212	packet_put_cstring(service);
	213	packet_send();
	214	packet_write_wait();
	215	} else {
	216	debug("bad service request %s", service);
	217	packet_disconnect("bad service request %s", service);
	218	}
	219	xfree(service);
	220	}
	221
30460aeb	222	/ARGSUSED/
3c0ef626	223	static void
1e608e42	224	input_userauth_request(int type, u_int32_t seq, void *ctxt)
3c0ef626	225	{
	226	Authctxt *authctxt = ctxt;
	227	Authmethod *m = NULL;
	228	char user, service, method, style = NULL;
	229	int authenticated = 0;
	230
	231	if (authctxt == NULL)
	232	fatal("input_userauth_request: no authctxt");
	233
	234	user = packet_get_string(NULL);
	235	service = packet_get_string(NULL);
	236	method = packet_get_string(NULL);
73a68d83	237
305d07c0	238	#ifdef GSSAPI
8f3eb4db	239	if (user[0] == '\0') {
b8e8844a	240	debug("received empty username for %s", method);
fe4ad273	241	if (strcmp(method, "external-keyx") == 0 \|\|
fe4ad273	242	strcmp(method, "gssapi-keyex") == 0) {
b8e8844a	243	char *lname = NULL;
	244	PRIVSEP(ssh_gssapi_localname(&lname));
	245	if (lname && lname[0] != '\0') {
	246	xfree(user);
	247	user = lname;
	248	debug("set username to %s from gssapi context", user);
9ec9d5ad	249	} else {
b8e8844a	250	debug("failed to set username from gssapi context");
d9e17760	251	packet_send_debug("failed to set username from gssapi context");
b8e8844a	252	}
b59afbfe	253	}
	254	}
	255	#endif
73a68d83	256
b8e8844a	257	debug("userauth-request for user %s service %s method %s",
8f3eb4db	258	user[0] ? user : "<implicit>", service, method);
fa7499cc	259	if (!log_flag) {
fa7499cc	260	logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s",
d3057ca4	261	get_remote_ipaddr(), get_remote_port(),
d3057ca4	262	user[0] ? user : "<implicit>");
fa7499cc	263	log_flag = 1;
fa7499cc	264	}
3c0ef626	265	debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
	266
	267	if ((style = strchr(user, ':')) != NULL)
	268	*style++ = 0;
	269
86a22a0a	270	/* If first time or username changed or empty username,
781f72b9	271	setup/reset authentication context. */
	272	if ((authctxt->attempt++ == 0) \|\|
	273	(strcmp(user, authctxt->user) != 0) \|\|
	274	(strcmp(user, "") == 0)) {
b59afbfe	275	if (authctxt->user) {
	276	xfree(authctxt->user);
	277	authctxt->user = NULL;
	278	}
b809a58e	279	authctxt->valid = 0;
86a22a0a	280	authctxt->user = xstrdup(user);
	281	if (strcmp(service, "ssh-connection") != 0) {
	282	packet_disconnect("Unsupported service %s", service);
	283	}
b8e8844a	284	#ifdef GSSAPI
9ec9d5ad	285	/* If we're going to set the username based on the
9ec9d5ad	286	GSSAPI context later, then wait until then to
8f3eb4db	287	verify it. Just put in placeholders for now. */
	288	if ((strcmp(user, "") == 0) &&
	289	((strcmp(method, "gssapi") == 0) \|\|
	290	(strcmp(method, "gssapi-with-mic") == 0))) {
	291	authctxt->pw = fakepw();
8f3eb4db	292	} else {
b8e8844a	293	#endif
510132b6	294	authctxt->pw = PRIVSEP(getpwnamallow(user));
86a22a0a	295	if (authctxt->pw) {
3c0ef626	296	authctxt->valid = 1;
3c0ef626	297	debug2("input_userauth_request: setting up authctxt for %s", user);
3c0ef626	298	} else {
7e82606e	299	logit("input_userauth_request: invalid user %s", user);
7cac2b65	300	authctxt->pw = fakepw();
dfddba3d	301	#ifdef SSH_AUDIT_EVENTS
dfddba3d	302	PRIVSEP(audit_event(SSH_INVALID_USER));
3c0ef626	303	#endif
3c0ef626	304	}
b8e8844a	305	#ifdef GSSAPI
9ec9d5ad	306	} /* endif for setting username based on GSSAPI context */
08822d99	307	#endif
	308	#ifdef USE_PAM
	309	if (options.use_pam)
	310	PRIVSEP(start_pam(authctxt));
b8e8844a	311	#endif
7e82606e	312	setproctitle("%s%s", authctxt->valid ? user : "unknown",
510132b6	313	use_privsep ? " [net]" : "");
88ca8dfd	314	if (authctxt->attempt == 1) {
86a22a0a	315	authctxt->service = xstrdup(service);
	316	authctxt->style = style ? xstrdup(style) : NULL;
	317	if (use_privsep)
	318	mm_inform_authserv(service, style);
5156b1a1	319	userauth_banner();
86a22a0a	320	}
885ffc2b	321	}
885ffc2b	322	if (strcmp(service, authctxt->service) != 0) {
67b84e65	323	packet_disconnect("Change of service not allowed: "
	324	"(%s,%s) -> (%s,%s)",
	325	authctxt->user, authctxt->service, user, service);
3c0ef626	326	}
3c0ef626	327	/* reset state */
1e608e42	328	auth2_challenge_stop(authctxt);
5262cbfb	329	#ifdef JPAKE
	330	auth2_jpake_stop(authctxt);
	331	#endif
5598e598	332
5598e598	333	#ifdef GSSAPI
5262cbfb	334	/* XXX move to auth2_gssapi_stop() */
1e608e42	335	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
1e608e42	336	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
5598e598	337	#endif
5598e598	338
3c0ef626	339	authctxt->postponed = 0;
fe4ad273	340	authctxt->server_caused_failure = 0;
3c0ef626	341
	342	/* try to authenticate user */
	343	m = authmethod_lookup(method);
5156b1a1	344	if (m != NULL && authctxt->failures < options.max_authtries) {
3c0ef626	345	debug2("input_userauth_request: try method %s", method);
	346	authenticated = m->userauth(authctxt);
	347	}
	348	userauth_finish(authctxt, authenticated, method);
	349
	350	xfree(service);
	351	xfree(user);
	352	xfree(method);
	353	}
	354
	355	void
	356	userauth_finish(Authctxt authctxt, int authenticated, char method)
	357	{
	358	char *methods;
	359
	360	if (!authctxt->valid && authenticated)
	361	fatal("INTERNAL ERROR: authenticated invalid user %s",
	362	authctxt->user);
	363
	364	/* Special handling for root */
bfe49944	365	if (authenticated && authctxt->pw->pw_uid == 0 &&
dfddba3d	366	!auth_root_allowed(method)) {
3c0ef626	367	authenticated = 0;
dfddba3d	368	#ifdef SSH_AUDIT_EVENTS
	369	PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
	370	#endif
	371	}
3c0ef626	372
3c0ef626	373	#ifdef USE_PAM
dfddba3d	374	if (options.use_pam && authenticated) {
	375	if (!PRIVSEP(do_pam_account())) {
	376	/* if PAM returned a message, send it to the user */
	377	if (buffer_len(&loginmsg) > 0) {
	378	buffer_append(&loginmsg, "\0", 1);
	379	userauth_send_banner(buffer_ptr(&loginmsg));
	380	packet_write_wait();
	381	}
	382	fatal("Access denied for user %s by PAM account "
2ce0bfe4	383	"configuration", authctxt->user);
dfddba3d	384	}
dfddba3d	385	}
7cac2b65	386	#endif
3c0ef626	387
d03f4262	388	#ifdef _UNICOS
	389	if (authenticated && cray_access_denied(authctxt->user)) {
	390	authenticated = 0;
	391	fatal("Access denied for user %s.",authctxt->user);
	392	}
	393	#endif /* _UNICOS */
	394
3c0ef626	395	/* Log before sending the reply */
	396	auth_log(authctxt, authenticated, method, " ssh2");
	397
	398	if (authctxt->postponed)
	399	return;
	400
	401	/* XXX todo: check if multiple auth methods are needed */
	402	if (authenticated == 1) {
	403	/* turn off userauth */
1e608e42	404	dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
3c0ef626	405	packet_start(SSH2_MSG_USERAUTH_SUCCESS);
	406	packet_send();
	407	packet_write_wait();
	408	/* now we can break out */
	409	authctxt->success = 1;
	410	} else {
fe4ad273	411	/* Dont count server configuration issues against the client */
5156b1a1	412	/* Allow initial try of "none" auth without failure penalty */
5156b1a1	413	if (!authctxt->server_caused_failure &&
f97edba6	414	(authctxt->attempt > 1 \|\| strcmp(method, "none") != 0))
5156b1a1	415	authctxt->failures++;
5156b1a1	416	if (authctxt->failures >= options.max_authtries) {
dfddba3d	417	#ifdef SSH_AUDIT_EVENTS
	418	PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
	419	#endif
3c0ef626	420	packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
dfddba3d	421	}
3c0ef626	422	methods = authmethods_get();
	423	packet_start(SSH2_MSG_USERAUTH_FAILURE);
	424	packet_put_cstring(methods);
	425	packet_put_char(0); /* XXX partial success, unused */
	426	packet_send();
	427	packet_write_wait();
	428	xfree(methods);
	429	}
	430	}
	431
3c0ef626	432	static char *
	433	authmethods_get(void)
	434	{
1e608e42	435	Buffer b;
3c0ef626	436	char *list;
44a053a3	437	int i;
3c0ef626	438
1e608e42	439	buffer_init(&b);
44a053a3	440	for (i = 0; authmethods[i] != NULL; i++) {
44a053a3	441	if (strcmp(authmethods[i]->name, "none") == 0)
3c0ef626	442	continue;
44a053a3	443	if (authmethods[i]->enabled != NULL &&
44a053a3	444	*(authmethods[i]->enabled) != 0) {
1e608e42	445	if (buffer_len(&b) > 0)
1e608e42	446	buffer_append(&b, ",", 1);
44a053a3	447	buffer_append(&b, authmethods[i]->name,
44a053a3	448	strlen(authmethods[i]->name));
3c0ef626	449	}
3c0ef626	450	}
1e608e42	451	buffer_append(&b, "\0", 1);
	452	list = xstrdup(buffer_ptr(&b));
	453	buffer_free(&b);
3c0ef626	454	return list;
	455	}
	456
	457	static Authmethod *
	458	authmethod_lookup(const char *name)
	459	{
44a053a3	460	int i;
44a053a3	461
3c0ef626	462	if (name != NULL)
44a053a3	463	for (i = 0; authmethods[i] != NULL; i++)
	464	if (authmethods[i]->enabled != NULL &&
	465	*(authmethods[i]->enabled) != 0 &&
	466	strcmp(name, authmethods[i]->name) == 0)
	467	return authmethods[i];
	468	debug2("Unrecognized authentication method name: %s",
	469	name ? name : "NULL");
3c0ef626	470	return NULL;
3c0ef626	471	}
5156b1a1	472