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

/*	$OpenBSD: gss-serv.c,v 1.8 2005/08/30 22:08:05 djm 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;
#endif
#ifdef GSI
extern ssh_gssapi_mech gssapi_gsi_mech;
#endif

ssh_gssapi_mech* supported_mechs[]= {
#ifdef KRB5
	&gssapi_kerberos_mech,
#endif
#ifdef GSI
	&gssapi_gsi_mech,
#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)
{
	u_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)
{
	OM_uint32 lmin;

	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)
		if ((*gssapi_client.mech->userok)(&gssapi_client, user))
			return 1;
		else {
			/* Destroy delegated credentials if userok fails */
			gss_release_buffer(&lmin, &gssapi_client.displayname);
			gss_release_buffer(&lmin, &gssapi_client.exportedname);
			gss_release_cred(&lmin, &gssapi_client.creds);
			memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
			return 0;
		}
	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;

	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) {
	    options.gss_authentication = 0; /* no mechs. skip gss auth. */
	    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
2ce0bfe4	1	/* $OpenBSD: gss-serv.c,v 1.8 2005/08/30 22:08:05 djm Exp $ */
7cac2b65	2
5598e598	3	/*
23987cb8	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"
e5affddc	38	#include "channels.h"
5598e598	39	#include "session.h"
5598e598	40	#include "servconf.h"
b59afbfe	41	#include "monitor_wrap.h"
7cac2b65	42	#include "xmalloc.h"
7cac2b65	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
23987cb8	51	static ssh_gssapi_client gssapi_client =
7cac2b65	52	{ GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
7cac2b65	53	GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
5598e598	54
7cac2b65	55	ssh_gssapi_mech gssapi_null_mech =
7cac2b65	56	{ NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
44a053a3	57
5598e598	58	#ifdef KRB5
23987cb8	59	extern ssh_gssapi_mech gssapi_kerberos_mech;
54425c7a	60	#endif
5598e598	61	#ifdef GSI
23987cb8	62	extern ssh_gssapi_mech gssapi_gsi_mech;
b311f64e	63	#endif
b311f64e	64
23987cb8	65	ssh_gssapi_mech* supported_mechs[]= {
5598e598	66	#ifdef KRB5
7cac2b65	67	&gssapi_kerberos_mech,
5598e598	68	#endif
5598e598	69	#ifdef GSI
7cac2b65	70	&gssapi_gsi_mech,
7b5a625b	71	#endif
7cac2b65	72	&gssapi_null_mech,
23987cb8	73	};
5598e598	74
b4cfa386	75	#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	76	static int limited = 0;
	77	#endif
	78
7cac2b65	79	/* Unpriviledged */
	80	void
	81	ssh_gssapi_supported_oids(gss_OID_set *oidset)
	82	{
	83	int i = 0;
	84	OM_uint32 min_status;
	85	int present;
	86	gss_OID_set supported;
	87
	88	gss_create_empty_oid_set(&min_status, oidset);
186e1568	89	/* Ask priviledged process what mechanisms it supports. */
186e1568	90	PRIVSEP(gss_indicate_mechs(&min_status, &supported));
7cac2b65	91
	92	while (supported_mechs[i]->name != NULL) {
	93	if (GSS_ERROR(gss_test_oid_set_member(&min_status,
	94	&supported_mechs[i]->oid, supported, &present)))
	95	present = 0;
	96	if (present)
	97	gss_add_oid_set_member(&min_status,
	98	&supported_mechs[i]->oid, oidset);
	99	i++;
	100	}
	101	}
	102
	103
	104	/* Wrapper around accept_sec_context
	105	* Requires that the context contains:
	106	* oid
	107	* credentials (from ssh_gssapi_acquire_cred)
	108	*/
	109	/* Priviledged */
	110	OM_uint32
	111	ssh_gssapi_accept_ctx(Gssctxt ctx, gss_buffer_desc recv_tok,
	112	gss_buffer_desc send_tok, OM_uint32 flags)
	113	{
	114	OM_uint32 status;
	115	gss_OID mech;
	116
	117	ctx->major = gss_accept_sec_context(&ctx->minor,
	118	&ctx->context, ctx->creds, recv_tok,
	119	GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
	120	send_tok, flags, NULL, &ctx->client_creds);
	121
	122	if (GSS_ERROR(ctx->major))
	123	ssh_gssapi_error(ctx);
	124
	125	if (ctx->client_creds)
	126	debug("Received some client credentials");
	127	else
	128	debug("Got no client credentials");
	129
	130	status = ctx->major;
	131
	132	/* Now, if we're complete and we have the right flags, then
	133	* we flag the user as also having been authenticated
	134	*/
	135
	136	if (((flags == NULL) \|\| ((*flags & GSS_C_MUTUAL_FLAG) &&
	137	(*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
	138	if (ssh_gssapi_getclient(ctx, &gssapi_client))
	139	fatal("Couldn't convert client name");
b4cfa386	140	#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	141	if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
	142	limited=1;
	143	#endif
7cac2b65	144	}
	145
	146	return (status);
	147	}
	148
	149	/*
	150	* This parses an exported name, extracting the mechanism specific portion
	151	* to use for ACL checking. It verifies that the name belongs the mechanism
	152	* originally selected.
	153	*/
	154	static OM_uint32
	155	ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
	156	{
2ce0bfe4	157	u_char *tok;
7cac2b65	158	OM_uint32 offset;
	159	OM_uint32 oidl;
	160
	161	tok=ename->value;
	162
	163	#ifdef GSI /* GSI gss_export_name() is broken. */
	164	if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
	165	(memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
	166	gssapi_gsi_mech.oid.length) == 0)) {
	167	name->length = ename->length;
	168	name->value = xmalloc(ename->length+1);
	169	memcpy(name->value, ename->value, ename->length);
	170	return GSS_S_COMPLETE;
	171	}
	172	#endif
	173
	174	/*
	175	* Check that ename is long enough for all of the fixed length
	176	* header, and that the initial ID bytes are correct
	177	*/
	178
	179	if (ename->length<6 \|\| memcmp(tok,"\x04\x01", 2)!=0)
	180	return GSS_S_FAILURE;
	181
	182	/*
	183	* Extract the OID, and check it. Here GSSAPI breaks with tradition
	184	* and does use the OID type and length bytes. To confuse things
	185	* there are two lengths - the first including these, and the
	186	* second without.
	187	*/
	188
	189	oidl = GET_16BIT(tok+2); /* length including next two bytes */
	190	oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
	191
	192	/*
	193	* Check the BER encoding for correct type and length, that the
	194	* string is long enough and that the OID matches that in our context
	195	*/
	196	if (tok[4] != 0x06 \|\| tok[5] != oidl \|\|
	197	ename->length < oidl+6 \|\|
2ce0bfe4	198	!ssh_gssapi_check_oid(ctx,tok+6,oidl))
7cac2b65	199	return GSS_S_FAILURE;
	200
	201	offset = oidl+6;
	202
	203	if (ename->length < offset+4)
	204	return GSS_S_FAILURE;
	205
	206	name->length = GET_32BIT(tok+offset);
	207	offset += 4;
	208
	209	if (ename->length < offset+name->length)
	210	return GSS_S_FAILURE;
	211
	212	name->value = xmalloc(name->length+1);
	213	memcpy(name->value,tok+offset,name->length);
	214	((char *)name->value)[name->length] = 0;
	215
	216	return GSS_S_COMPLETE;
	217	}
	218
	219	/* Extract the client details from a given context. This can only reliably
	220	* be called once for a context */
	221
	222	/* Priviledged (called from accept_secure_ctx) */
	223	OM_uint32
	224	ssh_gssapi_getclient(Gssctxt ctx, ssh_gssapi_client client)
	225	{
	226	int i = 0;
	227
	228	gss_buffer_desc ename;
	229
	230	client->mech = NULL;
	231
	232	while (supported_mechs[i]->name != NULL) {
	233	if (supported_mechs[i]->oid.length == ctx->oid->length &&
	234	(memcmp(supported_mechs[i]->oid.elements,
	235	ctx->oid->elements, ctx->oid->length) == 0))
	236	client->mech = supported_mechs[i];
	237	i++;
	238	}
	239
	240	if (client->mech == NULL)
	241	return GSS_S_FAILURE;
	242
	243	if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
	244	&client->displayname, NULL))) {
	245	ssh_gssapi_error(ctx);
	246	return (ctx->major);
	247	}
	248
	249	if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
	250	&ename))) {
	251	ssh_gssapi_error(ctx);
	252	return (ctx->major);
	253	}
	254
	255	if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
	256	&client->exportedname))) {
	257	return (ctx->major);
	258	}
	259
	260	/* We can't copy this structure, so we just move the pointer to it */
	261	client->creds = ctx->client_creds;
	262	ctx->client_creds = GSS_C_NO_CREDENTIAL;
263	return (ctx->major);
264	}
265
540d72c3	266	/* As user - called on fatal/exit */
7cac2b65	267	void
540d72c3	268	ssh_gssapi_cleanup_creds(void)
7cac2b65	269	{
	270	if (gssapi_client.store.filename != NULL) {
	271	/* Unlink probably isn't sufficient */
	272	debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
	273	unlink(gssapi_client.store.filename);
	274	}
	275	}
	276
	277	/* As user */
	278	void
	279	ssh_gssapi_storecreds(void)
	280	{
	281	if (gssapi_client.mech && gssapi_client.mech->storecreds) {
	282	(*gssapi_client.mech->storecreds)(&gssapi_client);
7cac2b65	283	} else
	284	debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
	285	}
	286
	287	/* This allows GSSAPI methods to do things to the childs environment based
	288	* on the passed authentication process and credentials.
	289	*/
	290	/* As user */
	291	void
	292	ssh_gssapi_do_child(char **envp, u_int envsizep)
	293	{
	294
	295	if (gssapi_client.store.envvar != NULL &&
	296	gssapi_client.store.envval != NULL) {
	297
	298	debug("Setting %s to %s", gssapi_client.store.envvar,
	299	gssapi_client.store.envval);
	300	child_set_env(envp, envsizep, gssapi_client.store.envvar,
2ce0bfe4	301	gssapi_client.store.envval);
7cac2b65	302	}
	303	}
	304
	305	/* Priviledged */
	306	int
	307	ssh_gssapi_userok(char *user)
	308	{
2ce0bfe4	309	OM_uint32 lmin;
2ce0bfe4	310
7cac2b65	311	if (gssapi_client.exportedname.length == 0 \|\|
	312	gssapi_client.exportedname.value == NULL) {
	313	debug("No suitable client data");
	314	return 0;
	315	}
b4cfa386	316	#ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
	317	if (limited) {
	318	debug("limited proxy not acceptable for remote login");
	319	return 0;
	320	}
	321	#endif
7cac2b65	322	if (gssapi_client.mech && gssapi_client.mech->userok)
2ce0bfe4	323	if ((*gssapi_client.mech->userok)(&gssapi_client, user))
	324	return 1;
	325	else {
	326	/* Destroy delegated credentials if userok fails */
	327	gss_release_buffer(&lmin, &gssapi_client.displayname);
	328	gss_release_buffer(&lmin, &gssapi_client.exportedname);
	329	gss_release_cred(&lmin, &gssapi_client.creds);
	330	memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
	331	return 0;
	332	}
7cac2b65	333	else
	334	debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
	335	return (0);
	336	}
	337
23987cb8	338	/* Return a list of the gss-group1-sha1-x mechanisms supported by this
23987cb8	339	* program.
5598e598	340	*
23987cb8	341	* We only support the mechanisms that we've indicated in the list above,
	342	* but we check that they're supported by the GSSAPI mechanism on the
	343	* machine. We also check, before including them in the list, that
	344	* we have the necesary information in order to carry out the key exchange
	345	* (that is, that the user has credentials, the server's creds are accessible,
	346	* etc)
	347	*
	348	* The way that this is done is fairly nasty, as we do a lot of work that
	349	* is then thrown away. This should possibly be implemented with a cache
	350	* that stores the results (in an expanded Gssctxt structure), which are
	351	* then used by the first calls if that key exchange mechanism is chosen.
6a8bca29	352	*/
e23e524c	353
e23e524c	354	/* Unpriviledged */
f001f132	355	char *
23987cb8	356	ssh_gssapi_server_mechanisms() {
f001f132	357	gss_OID_set supported;
23987cb8	358	Gssctxt *ctx = NULL;
f001f132	359	OM_uint32 maj_status, min_status;
	360	Buffer buf;
	361	int i = 0;
23987cb8	362	int first = 0;
f001f132	363	int present;
f001f132	364	char * mechs;
f001f132	365
23987cb8	366	ssh_gssapi_supported_oids(&supported);
f001f132	367
23987cb8	368	buffer_init(&buf);
f001f132	369
23987cb8	370	while(supported_mechs[i]->name != NULL) {
f001f132	371	if ((maj_status=gss_test_oid_set_member(&min_status,
23987cb8	372	&supported_mechs[i]->oid,
f001f132	373	supported,
	374	&present))) {
	375	present=0;
	376	}
23987cb8	377
f001f132	378	if (present) {
23987cb8	379	if (!GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
	380	&supported_mechs[i]->oid)))) {
	381	/* Append gss_group1_sha1_x to our list */
	382	if (first++!=0)
	383	buffer_put_char(&buf,',');
	384	buffer_append(&buf, KEX_GSS_SHA1,
	385	sizeof(KEX_GSS_SHA1)-1);
	386	buffer_append(&buf,
	387	supported_mechs[i]->enc_name,
	388	strlen(supported_mechs[i]->enc_name));
	389	debug("GSSAPI mechanism %s (%s%s) supported",
	390	supported_mechs[i]->name, KEX_GSS_SHA1,
	391	supported_mechs[i]->enc_name);
	392	} else {
	393	debug("no credentials for GSSAPI mechanism %s",
	394	supported_mechs[i]->name);
	395	}
	396	} else {
f001f132	397	debug("GSSAPI mechanism %s not supported",
23987cb8	398	supported_mechs[i]->name);
f001f132	399	}
23987cb8	400	ssh_gssapi_delete_ctx(&ctx);
	401	i++;
	402	}
f001f132	403
	404	buffer_put_char(&buf,'\0');
	405
	406	mechs=xmalloc(buffer_len(&buf));
	407	buffer_get(&buf,mechs,buffer_len(&buf));
	408	buffer_free(&buf);
f6c8c2f9	409	if (strlen(mechs)==0) {
	410	options.gss_authentication = 0; /* no mechs. skip gss auth. */
	411	return(NULL);
	412	} else {
	413	return(mechs);
	414	}
f001f132	415	}
f001f132	416
e23e524c	417	/* Return the OID that corresponds to the given context name */
23987cb8	418
e23e524c	419	/* Unpriviledged */
23987cb8	420	gss_OID
e23e524c	421	ssh_gssapi_server_id_kex(char *name) {
23987cb8	422	int i=0;
	423
	424	if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
	425	return(NULL);
	426	}
	427
	428	name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
	429
	430	while (supported_mechs[i]->name!=NULL &&
e23e524c	431	strcmp(name,supported_mechs[i]->enc_name)!=0) {
23987cb8	432	i++;
	433	}
	434
	435	if (supported_mechs[i]->name==NULL)
	436	return (NULL);
	437
23987cb8	438	debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
	439	KEX_GSS_SHA1, supported_mechs[i]->enc_name);
	440
	441	return &supported_mechs[i]->oid;
	442	}
	443
e23e524c	444	/* Priviledged */
23987cb8	445	int
	446	ssh_gssapi_localname(char **user)
	447	{
	448	*user = NULL;
7cac2b65	449	if (gssapi_client.displayname.length==0 \|\|
7cac2b65	450	gssapi_client.displayname.value==NULL) {
23987cb8	451	debug("No suitable client data");
	452	return(0);;
	453	}
	454	if (gssapi_client.mech && gssapi_client.mech->localname) {
	455	return((*gssapi_client.mech->localname)(&gssapi_client,user));
	456	} else {
	457	debug("Unknown client authentication type");
	458	}
	459	return(0);
	460	}
540d72c3	461
	462	/* Priviledged */
	463	OM_uint32
	464	ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
	465	{
	466	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	467	gssbuf, gssmic, NULL);
	468
	469	return (ctx->major);
	470	}
	471
23987cb8	472	#endif