[gssapi-openssh.git] / openssh / gss-serv.c

/*	$OpenBSD: gss-serv.c,v 1.5 2003/11/17 11:06:07 markus Exp $	*/

/*
 * Copyright (c) 2001-2003 Simon Wilkinson. 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"

#ifdef GSSAPI

#include "buffer.h"
#include "bufaux.h"
#include "compat.h"
#include <openssl/evp.h>
#include "kex.h"
#include "auth.h"
#include "log.h"
#include "channels.h"
#include "session.h"
#include "servconf.h"
#include "monitor_wrap.h"
#include "xmalloc.h"
#include "getput.h"

#include "ssh-gss.h"

extern ServerOptions options;
extern u_char *session_id2;
extern int session_id2_len;

static ssh_gssapi_client gssapi_client =
    { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
    GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};

ssh_gssapi_mech gssapi_null_mech =
    { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};

#ifdef KRB5
extern ssh_gssapi_mech gssapi_kerberos_mech;
extern ssh_gssapi_mech gssapi_kerberos_mech_old;
#endif
#ifdef GSI
extern ssh_gssapi_mech gssapi_gsi_mech;
extern ssh_gssapi_mech gssapi_gsi_mech_old;
#endif

ssh_gssapi_mech* supported_mechs[]= {
#ifdef KRB5
	&gssapi_kerberos_mech,
	&gssapi_kerberos_mech_old, /* Support for legacy clients */
#endif
#ifdef GSI
	&gssapi_gsi_mech,
	&gssapi_gsi_mech_old,	/* Support for legacy clients */
#endif
	&gssapi_null_mech,
};

#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
static int limited = 0;
#endif

/* Unpriviledged */
void
ssh_gssapi_supported_oids(gss_OID_set *oidset)
{
	int i = 0;
	OM_uint32 min_status;
	int present;
	gss_OID_set supported;

	gss_create_empty_oid_set(&min_status, oidset);
	/* Ask priviledged process what mechanisms it supports. */
	PRIVSEP(gss_indicate_mechs(&min_status, &supported));

	while (supported_mechs[i]->name != NULL) {
		if (GSS_ERROR(gss_test_oid_set_member(&min_status,
		    &supported_mechs[i]->oid, supported, &present)))
			present = 0;
		if (present)
			gss_add_oid_set_member(&min_status,
			    &supported_mechs[i]->oid, oidset);
		i++;
	}
}


/* Wrapper around accept_sec_context
 * Requires that the context contains:
 *    oid
 *    credentials	(from ssh_gssapi_acquire_cred)
 */
/* Priviledged */
OM_uint32
ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
    gss_buffer_desc *send_tok, OM_uint32 *flags)
{
	OM_uint32 status;
	gss_OID mech;

	ctx->major = gss_accept_sec_context(&ctx->minor,
	    &ctx->context, ctx->creds, recv_tok,
	    GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
	    send_tok, flags, NULL, &ctx->client_creds);

	if (GSS_ERROR(ctx->major))
		ssh_gssapi_error(ctx);

	if (ctx->client_creds)
		debug("Received some client credentials");
	else
		debug("Got no client credentials");

	status = ctx->major;

	/* Now, if we're complete and we have the right flags, then
	 * we flag the user as also having been authenticated
	 */

	if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
	    (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
		if (ssh_gssapi_getclient(ctx, &gssapi_client))
			fatal("Couldn't convert client name");
#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
		if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
			limited=1;
#endif
	}

	return (status);
}

/*
 * This parses an exported name, extracting the mechanism specific portion
 * to use for ACL checking. It verifies that the name belongs the mechanism
 * originally selected.
 */
static OM_uint32
ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
{
	char *tok;
	OM_uint32 offset;
	OM_uint32 oidl;

	tok=ename->value;

#ifdef GSI /* GSI gss_export_name() is broken. */
	if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
	    (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
		    gssapi_gsi_mech.oid.length) == 0)) {
	    name->length = ename->length;
	    name->value = xmalloc(ename->length+1);
	    memcpy(name->value, ename->value, ename->length);
	    return GSS_S_COMPLETE;
	}
#endif

	/*
	 * Check that ename is long enough for all of the fixed length
	 * header, and that the initial ID bytes are correct
	 */

	if (ename->length<6 || memcmp(tok,"\x04\x01", 2)!=0)
		return GSS_S_FAILURE;

	/*
	 * Extract the OID, and check it. Here GSSAPI breaks with tradition
	 * and does use the OID type and length bytes. To confuse things
	 * there are two lengths - the first including these, and the
	 * second without.
	 */

	oidl = GET_16BIT(tok+2); /* length including next two bytes */
	oidl = oidl-2; /* turn it into the _real_ length of the variable OID */

	/*
	 * Check the BER encoding for correct type and length, that the
	 * string is long enough and that the OID matches that in our context
	 */
	if (tok[4] != 0x06 || tok[5] != oidl ||
	    ename->length < oidl+6 ||
	   !ssh_gssapi_check_oid(ctx,tok+6,oidl))
		return GSS_S_FAILURE;

	offset = oidl+6;

	if (ename->length < offset+4)
		return GSS_S_FAILURE;

	name->length = GET_32BIT(tok+offset);
	offset += 4;

	if (ename->length < offset+name->length)
		return GSS_S_FAILURE;

	name->value = xmalloc(name->length+1);
	memcpy(name->value,tok+offset,name->length);
	((char *)name->value)[name->length] = 0;

	return GSS_S_COMPLETE;
}

/* Extract the client details from a given context. This can only reliably
 * be called once for a context */

/* Priviledged (called from accept_secure_ctx) */
OM_uint32
ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
{
	int i = 0;

	gss_buffer_desc ename;

	client->mech = NULL;

	while (supported_mechs[i]->name != NULL) {
		if (supported_mechs[i]->oid.length == ctx->oid->length &&
		    (memcmp(supported_mechs[i]->oid.elements,
		    ctx->oid->elements, ctx->oid->length) == 0))
			client->mech = supported_mechs[i];
		i++;
	}

	if (client->mech == NULL)
		return GSS_S_FAILURE;

	if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
	    &client->displayname, NULL))) {
		ssh_gssapi_error(ctx);
		return (ctx->major);
	}

	if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
	    &ename))) {
		ssh_gssapi_error(ctx);
		return (ctx->major);
	}

	if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
	    &client->exportedname))) {
		return (ctx->major);
	}

	/* We can't copy this structure, so we just move the pointer to it */
	client->creds = ctx->client_creds;
	ctx->client_creds = GSS_C_NO_CREDENTIAL;
	return (ctx->major);
}

/* As user - called on fatal/exit */
void
ssh_gssapi_cleanup_creds(void)
{
	if (gssapi_client.store.filename != NULL) {
		/* Unlink probably isn't sufficient */
		debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
		unlink(gssapi_client.store.filename);
	}
}

/* As user */
void
ssh_gssapi_storecreds(void)
{
	if (gssapi_client.mech && gssapi_client.mech->storecreds) {
		(*gssapi_client.mech->storecreds)(&gssapi_client);
	} else
		debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
}

/* This allows GSSAPI methods to do things to the childs environment based
 * on the passed authentication process and credentials.
 */
/* As user */
void
ssh_gssapi_do_child(char ***envp, u_int *envsizep)
{

	if (gssapi_client.store.envvar != NULL &&
	    gssapi_client.store.envval != NULL) {

		debug("Setting %s to %s", gssapi_client.store.envvar,
		gssapi_client.store.envval);
		child_set_env(envp, envsizep, gssapi_client.store.envvar,
		     gssapi_client.store.envval);
	}
}

/* Priviledged */
int
ssh_gssapi_userok(char *user)
{
	if (gssapi_client.exportedname.length == 0 ||
	    gssapi_client.exportedname.value == NULL) {
		debug("No suitable client data");
		return 0;
	}
#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	if (limited) {
		debug("limited proxy not acceptable for remote login");
		return 0;
	}
#endif
	if (gssapi_client.mech && gssapi_client.mech->userok)
		return ((*gssapi_client.mech->userok)(&gssapi_client, user));
	else
		debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
	return (0);
}

/* Return a list of the gss-group1-sha1-x mechanisms supported by this
 * program.
 *
 * We only support the mechanisms that we've indicated in the list above,
 * but we check that they're supported by the GSSAPI mechanism on the 
 * machine. We also check, before including them in the list, that
 * we have the necesary information in order to carry out the key exchange
 * (that is, that the user has credentials, the server's creds are accessible,
 * etc)
 *
 * The way that this is done is fairly nasty, as we do a lot of work that
 * is then thrown away. This should possibly be implemented with a cache
 * that stores the results (in an expanded Gssctxt structure), which are
 * then used by the first calls if that key exchange mechanism is chosen.
 */

/* Unpriviledged */ 
char * 
ssh_gssapi_server_mechanisms() {
	gss_OID_set 	supported;
	Gssctxt		*ctx = NULL;
	OM_uint32	maj_status, min_status;
	Buffer		buf;
	int 		i = 0;
	int		first = 0;
	int		present;
	char *		mechs;

	if (datafellows & SSH_OLD_GSSAPI) return NULL;
	
	ssh_gssapi_supported_oids(&supported);
	
	buffer_init(&buf);

	while(supported_mechs[i]->name != NULL) {
		if ((maj_status=gss_test_oid_set_member(&min_status,
						   	&supported_mechs[i]->oid,
						   	supported,
						   	&present))) {
			present=0;
		}

		if (present) {
		    if (!GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
					   &supported_mechs[i]->oid)))) {
			/* Append gss_group1_sha1_x to our list */
			if (first++!=0)
				buffer_put_char(&buf,',');
			buffer_append(&buf, KEX_GSS_SHA1,
				      sizeof(KEX_GSS_SHA1)-1);
	        	buffer_append(&buf, 
	        		      supported_mechs[i]->enc_name,
        	      		      strlen(supported_mechs[i]->enc_name));
			debug("GSSAPI mechanism %s (%s%s) supported",
			      supported_mechs[i]->name, KEX_GSS_SHA1,
			      supported_mechs[i]->enc_name);
		    } else {
			debug("no credentials for GSSAPI mechanism %s",
			      supported_mechs[i]->name);
		    }
        	} else {
		    debug("GSSAPI mechanism %s not supported",
			  supported_mechs[i]->name);
		}
        	ssh_gssapi_delete_ctx(&ctx);
        	i++;
	}
	
	buffer_put_char(&buf,'\0');
	
	mechs=xmalloc(buffer_len(&buf));
	buffer_get(&buf,mechs,buffer_len(&buf));
	buffer_free(&buf);
	if (strlen(mechs)==0)
	   return(NULL);
	else
	   return(mechs);
}

/* Return the OID that corresponds to the given context name */
 
/* Unpriviledged */
gss_OID 
ssh_gssapi_server_id_kex(char *name) {
  int i=0;
  
  if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
     return(NULL);
  }
  
  name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
  
  while (supported_mechs[i]->name!=NULL &&
  	 strcmp(name,supported_mechs[i]->enc_name)!=0) {
  	i++;
  }

  if (supported_mechs[i]->name==NULL)
     return (NULL);

  debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
	KEX_GSS_SHA1, supported_mechs[i]->enc_name);

  return &supported_mechs[i]->oid;
}

/* Priviledged */
int
ssh_gssapi_localname(char **user)
{
    	*user = NULL;
	if (gssapi_client.displayname.length==0 || 
	    gssapi_client.displayname.value==NULL) {
		debug("No suitable client data");
		return(0);;
	}
	if (gssapi_client.mech && gssapi_client.mech->localname) {
		return((*gssapi_client.mech->localname)(&gssapi_client,user));
	} else {
		debug("Unknown client authentication type");
	}
	return(0);
}

/* Priviledged */
OM_uint32
ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
{
	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	    gssbuf, gssmic, NULL);

	return (ctx->major);
}

#endif
Commit	Line	Data
416fd2a8	1	/* $OpenBSD: gss-serv.c,v 1.5 2003/11/17 11:06:07 markus Exp $ */
70791e56	2
5598e598	3	/*
88928908	4	* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
5598e598	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions and the following disclaimer.
	11	* 2. Redistributions in binary form must reproduce the above copyright
	12	* notice, this list of conditions and the following disclaimer in the
	13	* documentation and/or other materials provided with the distribution.
	14	*
	15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
	16	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	17	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	18	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	19	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	20	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	21	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	24	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25	*/
	26
	27	#include "includes.h"
	28
	29	#ifdef GSSAPI
	30
5598e598	31	#include "buffer.h"
5598e598	32	#include "bufaux.h"
5598e598	33	#include "compat.h"
5598e598	34	#include <openssl/evp.h>
5598e598	35	#include "kex.h"
	36	#include "auth.h"
	37	#include "log.h"
1e608e42	38	#include "channels.h"
5598e598	39	#include "session.h"
5598e598	40	#include "servconf.h"
ff2d7a98	41	#include "monitor_wrap.h"
70791e56	42	#include "xmalloc.h"
70791e56	43	#include "getput.h"
5598e598	44
	45	#include "ssh-gss.h"
	46
	47	extern ServerOptions options;
	48	extern u_char *session_id2;
	49	extern int session_id2_len;
	50
88928908	51	static ssh_gssapi_client gssapi_client =
70791e56	52	{ GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
70791e56	53	GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
5598e598	54
70791e56	55	ssh_gssapi_mech gssapi_null_mech =
70791e56	56	{ NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
ff2d7a98	57
5598e598	58	#ifdef KRB5
88928908	59	extern ssh_gssapi_mech gssapi_kerberos_mech;
88928908	60	extern ssh_gssapi_mech gssapi_kerberos_mech_old;
c2397a66	61	#endif
5598e598	62	#ifdef GSI
88928908	63	extern ssh_gssapi_mech gssapi_gsi_mech;
88928908	64	extern ssh_gssapi_mech gssapi_gsi_mech_old;
f2fd21a2	65	#endif
f2fd21a2	66
88928908	67	ssh_gssapi_mech* supported_mechs[]= {
5598e598	68	#ifdef KRB5
70791e56	69	&gssapi_kerberos_mech,
70791e56	70	&gssapi_kerberos_mech_old, /* Support for legacy clients */
5598e598	71	#endif
5598e598	72	#ifdef GSI
70791e56	73	&gssapi_gsi_mech,
70791e56	74	&gssapi_gsi_mech_old, /* Support for legacy clients */
67e2750c	75	#endif
70791e56	76	&gssapi_null_mech,
88928908	77	};
5598e598	78
2a304a95	79	#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	80	static int limited = 0;
	81	#endif
	82
70791e56	83	/* Unpriviledged */
	84	void
	85	ssh_gssapi_supported_oids(gss_OID_set *oidset)
	86	{
	87	int i = 0;
	88	OM_uint32 min_status;
	89	int present;
	90	gss_OID_set supported;
	91
	92	gss_create_empty_oid_set(&min_status, oidset);
2a304a95	93	/* Ask priviledged process what mechanisms it supports. */
2a304a95	94	PRIVSEP(gss_indicate_mechs(&min_status, &supported));
70791e56	95
	96	while (supported_mechs[i]->name != NULL) {
	97	if (GSS_ERROR(gss_test_oid_set_member(&min_status,
	98	&supported_mechs[i]->oid, supported, &present)))
	99	present = 0;
	100	if (present)
	101	gss_add_oid_set_member(&min_status,
	102	&supported_mechs[i]->oid, oidset);
	103	i++;
	104	}
	105	}
	106
	107
	108	/* Wrapper around accept_sec_context
	109	* Requires that the context contains:
	110	* oid
	111	* credentials (from ssh_gssapi_acquire_cred)
	112	*/
	113	/* Priviledged */
	114	OM_uint32
	115	ssh_gssapi_accept_ctx(Gssctxt ctx, gss_buffer_desc recv_tok,
	116	gss_buffer_desc send_tok, OM_uint32 flags)
	117	{
	118	OM_uint32 status;
	119	gss_OID mech;
	120
	121	ctx->major = gss_accept_sec_context(&ctx->minor,
	122	&ctx->context, ctx->creds, recv_tok,
	123	GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
	124	send_tok, flags, NULL, &ctx->client_creds);
	125
	126	if (GSS_ERROR(ctx->major))
	127	ssh_gssapi_error(ctx);
	128
	129	if (ctx->client_creds)
	130	debug("Received some client credentials");
	131	else
	132	debug("Got no client credentials");
	133
	134	status = ctx->major;
	135
	136	/* Now, if we're complete and we have the right flags, then
	137	* we flag the user as also having been authenticated
	138	*/
	139
	140	if (((flags == NULL) \|\| ((*flags & GSS_C_MUTUAL_FLAG) &&
	141	(*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
	142	if (ssh_gssapi_getclient(ctx, &gssapi_client))
	143	fatal("Couldn't convert client name");
2a304a95	144	#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	145	if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
	146	limited=1;
	147	#endif
70791e56	148	}
	149
	150	return (status);
	151	}
	152
	153	/*
	154	* This parses an exported name, extracting the mechanism specific portion
	155	* to use for ACL checking. It verifies that the name belongs the mechanism
	156	* originally selected.
	157	*/
	158	static OM_uint32
	159	ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
	160	{
	161	char *tok;
	162	OM_uint32 offset;
	163	OM_uint32 oidl;
	164
	165	tok=ename->value;
	166
	167	#ifdef GSI /* GSI gss_export_name() is broken. */
	168	if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
	169	(memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
	170	gssapi_gsi_mech.oid.length) == 0)) {
	171	name->length = ename->length;
	172	name->value = xmalloc(ename->length+1);
	173	memcpy(name->value, ename->value, ename->length);
	174	return GSS_S_COMPLETE;
	175	}
	176	#endif
	177
	178	/*
	179	* Check that ename is long enough for all of the fixed length
	180	* header, and that the initial ID bytes are correct
	181	*/
	182
	183	if (ename->length<6 \|\| memcmp(tok,"\x04\x01", 2)!=0)
	184	return GSS_S_FAILURE;
	185
	186	/*
	187	* Extract the OID, and check it. Here GSSAPI breaks with tradition
	188	* and does use the OID type and length bytes. To confuse things
	189	* there are two lengths - the first including these, and the
	190	* second without.
	191	*/
	192
	193	oidl = GET_16BIT(tok+2); /* length including next two bytes */
	194	oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
	195
	196	/*
	197	* Check the BER encoding for correct type and length, that the
	198	* string is long enough and that the OID matches that in our context
	199	*/
	200	if (tok[4] != 0x06 \|\| tok[5] != oidl \|\|
	201	ename->length < oidl+6 \|\|
	202	!ssh_gssapi_check_oid(ctx,tok+6,oidl))
	203	return GSS_S_FAILURE;
	204
	205	offset = oidl+6;
	206
	207	if (ename->length < offset+4)
	208	return GSS_S_FAILURE;
	209
	210	name->length = GET_32BIT(tok+offset);
	211	offset += 4;
212
213	if (ename->length < offset+name->length)
214	return GSS_S_FAILURE;
215
216	name->value = xmalloc(name->length+1);
217	memcpy(name->value,tok+offset,name->length);
218	((char *)name->value)[name->length] = 0;
219
220	return GSS_S_COMPLETE;
221	}
222
223	/* Extract the client details from a given context. This can only reliably
224	* be called once for a context */
225
226	/* Priviledged (called from accept_secure_ctx) */
227	OM_uint32
228	ssh_gssapi_getclient(Gssctxt ctx, ssh_gssapi_client client)
229	{
230	int i = 0;
231
232	gss_buffer_desc ename;
233
234	client->mech = NULL;
235
236	while (supported_mechs[i]->name != NULL) {
237	if (supported_mechs[i]->oid.length == ctx->oid->length &&
238	(memcmp(supported_mechs[i]->oid.elements,
239	ctx->oid->elements, ctx->oid->length) == 0))
240	client->mech = supported_mechs[i];
241	i++;
242	}
243
244	if (client->mech == NULL)
245	return GSS_S_FAILURE;
246
247	if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
248	&client->displayname, NULL))) {
249	ssh_gssapi_error(ctx);
250	return (ctx->major);
251	}
252
253	if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
254	&ename))) {
255	ssh_gssapi_error(ctx);
256	return (ctx->major);
257	}
258
259	if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
260	&client->exportedname))) {
261	return (ctx->major);
262	}
263
264	/* We can't copy this structure, so we just move the pointer to it */
265	client->creds = ctx->client_creds;
266	ctx->client_creds = GSS_C_NO_CREDENTIAL;
267	return (ctx->major);
268	}
269
416fd2a8	270	/* As user - called on fatal/exit */
70791e56	271	void
416fd2a8	272	ssh_gssapi_cleanup_creds(void)
70791e56	273	{
	274	if (gssapi_client.store.filename != NULL) {
	275	/* Unlink probably isn't sufficient */
	276	debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
	277	unlink(gssapi_client.store.filename);
	278	}
	279	}
	280
	281	/* As user */
	282	void
	283	ssh_gssapi_storecreds(void)
	284	{
	285	if (gssapi_client.mech && gssapi_client.mech->storecreds) {
	286	(*gssapi_client.mech->storecreds)(&gssapi_client);
70791e56	287	} else
	288	debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
	289	}
	290
	291	/* This allows GSSAPI methods to do things to the childs environment based
	292	* on the passed authentication process and credentials.
	293	*/
	294	/* As user */
	295	void
	296	ssh_gssapi_do_child(char **envp, u_int envsizep)
	297	{
	298
	299	if (gssapi_client.store.envvar != NULL &&
	300	gssapi_client.store.envval != NULL) {
	301
	302	debug("Setting %s to %s", gssapi_client.store.envvar,
	303	gssapi_client.store.envval);
	304	child_set_env(envp, envsizep, gssapi_client.store.envvar,
	305	gssapi_client.store.envval);
	306	}
	307	}
	308
	309	/* Priviledged */
	310	int
	311	ssh_gssapi_userok(char *user)
	312	{
	313	if (gssapi_client.exportedname.length == 0 \|\|
	314	gssapi_client.exportedname.value == NULL) {
	315	debug("No suitable client data");
	316	return 0;
	317	}
2a304a95	318	#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	319	if (limited) {
	320	debug("limited proxy not acceptable for remote login");
	321	return 0;
	322	}
	323	#endif
70791e56	324	if (gssapi_client.mech && gssapi_client.mech->userok)
	325	return ((*gssapi_client.mech->userok)(&gssapi_client, user));
	326	else
	327	debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
	328	return (0);
	329	}
	330
88928908	331	/* Return a list of the gss-group1-sha1-x mechanisms supported by this
88928908	332	* program.
5598e598	333	*
88928908	334	* We only support the mechanisms that we've indicated in the list above,
	335	* but we check that they're supported by the GSSAPI mechanism on the
	336	* machine. We also check, before including them in the list, that
	337	* we have the necesary information in order to carry out the key exchange
	338	* (that is, that the user has credentials, the server's creds are accessible,
	339	* etc)
	340	*
	341	* The way that this is done is fairly nasty, as we do a lot of work that
	342	* is then thrown away. This should possibly be implemented with a cache
	343	* that stores the results (in an expanded Gssctxt structure), which are
	344	* then used by the first calls if that key exchange mechanism is chosen.
6a8bca29	345	*/
6a8bca29	346
88928908	347	/* Unpriviledged */
1c14df9e	348	char *
88928908	349	ssh_gssapi_server_mechanisms() {
1c14df9e	350	gss_OID_set supported;
88928908	351	Gssctxt *ctx = NULL;
1c14df9e	352	OM_uint32 maj_status, min_status;
	353	Buffer buf;
	354	int i = 0;
88928908	355	int first = 0;
1c14df9e	356	int present;
1c14df9e	357	char * mechs;
1c14df9e	358
	359	if (datafellows & SSH_OLD_GSSAPI) return NULL;
	360
88928908	361	ssh_gssapi_supported_oids(&supported);
1c14df9e	362
88928908	363	buffer_init(&buf);
1c14df9e	364
88928908	365	while(supported_mechs[i]->name != NULL) {
1c14df9e	366	if ((maj_status=gss_test_oid_set_member(&min_status,
88928908	367	&supported_mechs[i]->oid,
1c14df9e	368	supported,
	369	&present))) {
	370	present=0;
	371	}
88928908	372
1c14df9e	373	if (present) {
88928908	374	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
	375	&supported_mechs[i]->oid)))) {
	376	/* Append gss_group1_sha1_x to our list */
	377	if (first++!=0)
	378	buffer_put_char(&buf,',');
	379	buffer_append(&buf, KEX_GSS_SHA1,
	380	sizeof(KEX_GSS_SHA1)-1);
	381	buffer_append(&buf,
	382	supported_mechs[i]->enc_name,
	383	strlen(supported_mechs[i]->enc_name));
	384	debug("GSSAPI mechanism %s (%s%s) supported",
	385	supported_mechs[i]->name, KEX_GSS_SHA1,
	386	supported_mechs[i]->enc_name);
	387	} else {
	388	debug("no credentials for GSSAPI mechanism %s",
	389	supported_mechs[i]->name);
	390	}
	391	} else {
1c14df9e	392	debug("GSSAPI mechanism %s not supported",
88928908	393	supported_mechs[i]->name);
1c14df9e	394	}
88928908	395	ssh_gssapi_delete_ctx(&ctx);
	396	i++;
	397	}
1c14df9e	398
	399	buffer_put_char(&buf,'\0');
	400
	401	mechs=xmalloc(buffer_len(&buf));
	402	buffer_get(&buf,mechs,buffer_len(&buf));
	403	buffer_free(&buf);
	404	if (strlen(mechs)==0)
	405	return(NULL);
	406	else
	407	return(mechs);
	408	}
	409
88928908	410	/* Return the OID that corresponds to the given context name */
	411
	412	/* Unpriviledged */
	413	gss_OID
	414	ssh_gssapi_server_id_kex(char *name) {
	415	int i=0;
	416
	417	if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
	418	return(NULL);
	419	}
	420
	421	name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
	422
	423	while (supported_mechs[i]->name!=NULL &&
	424	strcmp(name,supported_mechs[i]->enc_name)!=0) {
	425	i++;
	426	}
	427
	428	if (supported_mechs[i]->name==NULL)
	429	return (NULL);
	430
	431	debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
	432	KEX_GSS_SHA1, supported_mechs[i]->enc_name);
	433
	434	return &supported_mechs[i]->oid;
	435	}
	436
88928908	437	/* Priviledged */
	438	int
	439	ssh_gssapi_localname(char **user)
	440	{
	441	*user = NULL;
70791e56	442	if (gssapi_client.displayname.length==0 \|\|
70791e56	443	gssapi_client.displayname.value==NULL) {
88928908	444	debug("No suitable client data");
	445	return(0);;
	446	}
	447	if (gssapi_client.mech && gssapi_client.mech->localname) {
	448	return((*gssapi_client.mech->localname)(&gssapi_client,user));
	449	} else {
	450	debug("Unknown client authentication type");
	451	}
	452	return(0);
	453	}
416fd2a8	454
	455	/* Priviledged */
	456	OM_uint32
	457	ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
	458	{
	459	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	460	gssbuf, gssmic, NULL);
	461
	462	return (ctx->major);
	463	}
	464
88928908	465	#endif