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

/* $OpenBSD: gss-genr.c,v 1.17 2006/08/29 12:02:30 dtucker Exp $ */

/*
 * Copyright (c) 2001-2006 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 <sys/types.h>
#include <sys/param.h>

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

#include "xmalloc.h"
#include "buffer.h"
#include "log.h"
#include "ssh2.h"
#include "cipher.h"
#include "key.h"
#include "kex.h"
#include <openssl/evp.h>

#include "ssh-gss.h"

extern u_char *session_id2;
extern u_int session_id2_len;

typedef struct {
	char *encoded;
	gss_OID oid;
} ssh_gss_kex_mapping;

/*
 * XXX - It would be nice to find a more elegant way of handling the
 * XXX   passing of the key exchange context to the userauth routines
 */

Gssctxt *gss_kex_context = NULL;

static ssh_gss_kex_mapping *gss_enc2oid = NULL;

int 
ssh_gssapi_oid_table_ok() {
	return (gss_enc2oid != NULL);
}

/*
 * Return a list of the gss-group1-sha1 mechanisms supported by this program
 *
 * We test mechanisms to ensure that we can use them, to avoid starting
 * a key exchange with a bad mechanism
 */

char *
ssh_gssapi_client_mechanisms(const char *host) {
	gss_OID_set gss_supported;
	OM_uint32 min_status;

	gss_indicate_mechs(&min_status, &gss_supported);

	return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
	    host));
}

char *
ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
    const char *data) {
	Buffer buf;
	size_t i;
	int oidpos, enclen;
	char *mechs, *encoded;
	u_char digest[EVP_MAX_MD_SIZE];
	char deroid[2];
	const EVP_MD *evp_md = EVP_md5();
	EVP_MD_CTX md;

	if (gss_enc2oid != NULL) {
		for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
			xfree(gss_enc2oid[i].encoded);
		xfree(gss_enc2oid);
	}

	gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping)*
	    (gss_supported->count + 1));

	buffer_init(&buf);

	oidpos = 0;
	for (i = 0; i < gss_supported->count; i++) {
		if (gss_supported->elements[i].length < 128 &&
		    (*check)(NULL, &(gss_supported->elements[i]), data)) {
			deroid[0] = SSH_GSS_OIDTYPE;
			deroid[1] = gss_supported->elements[i].length;

			EVP_DigestInit(&md, evp_md);
			EVP_DigestUpdate(&md, deroid, 2);
			EVP_DigestUpdate(&md,
			    gss_supported->elements[i].elements,
			    gss_supported->elements[i].length);
			EVP_DigestFinal(&md, digest, NULL);

			encoded = xmalloc(EVP_MD_size(evp_md) * 2);
			enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
			    encoded, EVP_MD_size(evp_md) * 2);

			if (oidpos != 0)
				buffer_put_char(&buf, ',');

			buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
			    sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
			buffer_append(&buf, encoded, enclen);
			buffer_put_char(&buf, ',');
			buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID, 
			    sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
			buffer_append(&buf, encoded, enclen);
			buffer_put_char(&buf, ',');
			buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
			    sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
			buffer_append(&buf, encoded, enclen);

			gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
			gss_enc2oid[oidpos].encoded = encoded;
			oidpos++;
		}
	}
	gss_enc2oid[oidpos].oid = NULL;
	gss_enc2oid[oidpos].encoded = NULL;

	buffer_put_char(&buf, '\0');

	mechs = xmalloc(buffer_len(&buf));
	buffer_get(&buf, mechs, buffer_len(&buf));
	buffer_free(&buf);

	if (strlen(mechs) == 0) {
		xfree(mechs);
		mechs = NULL;
	}
	
	return (mechs);
}

gss_OID
ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
	int i = 0;
	
	switch (kex_type) {
	case KEX_GSS_GRP1_SHA1:
		name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
		break;
	case KEX_GSS_GRP14_SHA1:
		name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
		break;
	case KEX_GSS_GEX_SHA1:
		name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
		break;
	default:
		return GSS_C_NO_OID;
	}

	while (gss_enc2oid[i].encoded != NULL &&
	    strcmp(name, gss_enc2oid[i].encoded) != 0)
		i++;

	if (gss_enc2oid[i].oid != NULL && ctx != NULL)
		ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);

	return gss_enc2oid[i].oid;
}

/* Check that the OID in a data stream matches that in the context */
int
ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
{
	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	    ctx->oid->length == len &&
	    memcmp(ctx->oid->elements, data, len) == 0);
}

/* Set the contexts OID from a data stream */
void
ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
{
	if (ctx->oid != GSS_C_NO_OID) {
		xfree(ctx->oid->elements);
		xfree(ctx->oid);
	}
	ctx->oid = xmalloc(sizeof(gss_OID_desc));
	ctx->oid->length = len;
	ctx->oid->elements = xmalloc(len);
	memcpy(ctx->oid->elements, data, len);
}

/* Set the contexts OID */
void
ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
{
	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
}

/* All this effort to report an error ... */
void
ssh_gssapi_error(Gssctxt *ctxt)
{
	char *s;

	s = ssh_gssapi_last_error(ctxt, NULL, NULL);
	debug("%s", s);
	xfree(s);
}

char *
ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
    OM_uint32 *minor_status)
{
	OM_uint32 lmin;
	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	OM_uint32 ctx;
	Buffer b;
	char *ret;

	buffer_init(&b);

	if (major_status != NULL)
		*major_status = ctxt->major;
	if (minor_status != NULL)
		*minor_status = ctxt->minor;

	ctx = 0;
	/* The GSSAPI error */
	do {
		gss_display_status(&lmin, ctxt->major,
		    GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);

		buffer_append(&b, msg.value, msg.length);
		buffer_put_char(&b, '\n');

		gss_release_buffer(&lmin, &msg);
	} while (ctx != 0);

	/* The mechanism specific error */
	do {
		gss_display_status(&lmin, ctxt->minor,
		    GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);

		buffer_append(&b, msg.value, msg.length);
		buffer_put_char(&b, '\n');

		gss_release_buffer(&lmin, &msg);
	} while (ctx != 0);

	buffer_put_char(&b, '\0');
	ret = xmalloc(buffer_len(&b));
	buffer_get(&b, ret, buffer_len(&b));
	buffer_free(&b);
	return (ret);
}

/*
 * Initialise our GSSAPI context. We use this opaque structure to contain all
 * of the data which both the client and server need to persist across
 * {accept,init}_sec_context calls, so that when we do it from the userauth
 * stuff life is a little easier
 */
void
ssh_gssapi_build_ctx(Gssctxt **ctx)
{
	*ctx = xcalloc(1, sizeof (Gssctxt));
	(*ctx)->context = GSS_C_NO_CONTEXT;
	(*ctx)->name = GSS_C_NO_NAME;
	(*ctx)->oid = GSS_C_NO_OID;
	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	(*ctx)->client = GSS_C_NO_NAME;
	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
}

/* Delete our context, providing it has been built correctly */
void
ssh_gssapi_delete_ctx(Gssctxt **ctx)
{
	OM_uint32 ms;

	if ((*ctx) == NULL)
		return;
	if ((*ctx)->context != GSS_C_NO_CONTEXT)
		gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
	if ((*ctx)->name != GSS_C_NO_NAME)
		gss_release_name(&ms, &(*ctx)->name);
	if ((*ctx)->oid != GSS_C_NO_OID) {
		xfree((*ctx)->oid->elements);
		xfree((*ctx)->oid);
		(*ctx)->oid = GSS_C_NO_OID;
	}
	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
		gss_release_cred(&ms, &(*ctx)->creds);
	if ((*ctx)->client != GSS_C_NO_NAME)
		gss_release_name(&ms, &(*ctx)->client);
	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
		gss_release_cred(&ms, &(*ctx)->client_creds);

	xfree(*ctx);
	*ctx = NULL;
}

/*
 * Wrapper to init_sec_context
 * Requires that the context contains:
 *	oid
 *	server name (from ssh_gssapi_import_name)
 */
OM_uint32
ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
    gss_buffer_desc* send_tok, OM_uint32 *flags)
{
	int deleg_flag = 0;

	if (deleg_creds) {
		deleg_flag = GSS_C_DELEG_FLAG;
		debug("Delegating credentials");
	}

	ctx->major = gss_init_sec_context(&ctx->minor,
	    GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
	    GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
	    0, NULL, recv_tok, NULL, send_tok, flags, NULL);

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

	return (ctx->major);
}

/* Create a service name for the given host */
OM_uint32
ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
{
	gss_buffer_desc gssbuf;
	char *val;

	xasprintf(&val, "host@%s", host);
	gssbuf.value = val;
	gssbuf.length = strlen(gssbuf.value);

	if ((ctx->major = gss_import_name(&ctx->minor,
	    &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
		ssh_gssapi_error(ctx);

	xfree(gssbuf.value);
	return (ctx->major);
}

OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
{
	if (ctx == NULL) 
		return -1;

	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
	    GSS_C_QOP_DEFAULT, buffer, hash)))
		ssh_gssapi_error(ctx);

	return (ctx->major);
}

/* Priviledged when used by server */
OM_uint32
ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
{
	if (ctx == NULL)
		return -1;

	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	    gssbuf, gssmic, NULL);

	return (ctx->major);
}

void
ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
    const char *context)
{
	buffer_init(b);
	buffer_put_string(b, session_id2, session_id2_len);
	buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
	buffer_put_cstring(b, user);
	buffer_put_cstring(b, service);
	buffer_put_cstring(b, context);
}

int
ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
{
	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
	OM_uint32 major, minor;
	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
	Gssctxt *intctx = NULL;

	if (ctx == NULL)
		ctx = &intctx;

	/* RFC 4462 says we MUST NOT do SPNEGO */
	if (oid->length == spnego_oid.length && 
	    (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
		return 0; /* false */

	ssh_gssapi_build_ctx(ctx);
	ssh_gssapi_set_oid(*ctx, oid);
	major = ssh_gssapi_import_name(*ctx, host);
	if (!GSS_ERROR(major)) {
		major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token, 
		    NULL);
		gss_release_buffer(&minor, &token);
		if ((*ctx)->context != GSS_C_NO_CONTEXT)
			gss_delete_sec_context(&minor, &(*ctx)->context,
			    GSS_C_NO_BUFFER);
	}

	if (GSS_ERROR(major) || intctx != NULL) 
		ssh_gssapi_delete_ctx(ctx);

	return (!GSS_ERROR(major));
}

#endif /* GSSAPI */
Commit	Line	Data
9108f8d9	1	/* $OpenBSD: gss-genr.c,v 1.17 2006/08/29 12:02:30 dtucker Exp $ */
0fff78ff	2
0fff78ff	3	/*
9108f8d9	4	* Copyright (c) 2001-2006 Simon Wilkinson. All rights reserved.
0fff78ff	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
9108f8d9	31	#include <sys/types.h>
	32	#include <sys/param.h>
	33
	34	#include <stdarg.h>
	35	#include <string.h>
	36	#include <unistd.h>
	37
0fff78ff	38	#include "xmalloc.h"
9108f8d9	39	#include "buffer.h"
0fff78ff	40	#include "log.h"
cdd66111	41	#include "ssh2.h"
659bdb8e	42	#include "cipher.h"
	43	#include "key.h"
	44	#include "kex.h"
	45	#include <openssl/evp.h>
0fff78ff	46
	47	#include "ssh-gss.h"
	48
cdd66111	49	extern u_char *session_id2;
cdd66111	50	extern u_int session_id2_len;
0fff78ff	51
659bdb8e	52	typedef struct {
	53	char *encoded;
	54	gss_OID oid;
	55	} ssh_gss_kex_mapping;
	56
	57	/*
	58	* XXX - It would be nice to find a more elegant way of handling the
	59	* XXX passing of the key exchange context to the userauth routines
	60	*/
	61
	62	Gssctxt *gss_kex_context = NULL;
	63
	64	static ssh_gss_kex_mapping *gss_enc2oid = NULL;
	65
	66	int
	67	ssh_gssapi_oid_table_ok() {
	68	return (gss_enc2oid != NULL);
	69	}
	70
	71	/*
	72	* Return a list of the gss-group1-sha1 mechanisms supported by this program
	73	*
	74	* We test mechanisms to ensure that we can use them, to avoid starting
	75	* a key exchange with a bad mechanism
	76	*/
	77
	78	char *
	79	ssh_gssapi_client_mechanisms(const char *host) {
	80	gss_OID_set gss_supported;
	81	OM_uint32 min_status;
	82
	83	gss_indicate_mechs(&min_status, &gss_supported);
	84
	85	return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
	86	host));
	87	}
	88
	89	char *
	90	ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
	91	const char *data) {
	92	Buffer buf;
	93	size_t i;
	94	int oidpos, enclen;
	95	char mechs, encoded;
	96	u_char digest[EVP_MAX_MD_SIZE];
	97	char deroid[2];
	98	const EVP_MD *evp_md = EVP_md5();
	99	EVP_MD_CTX md;
	100
	101	if (gss_enc2oid != NULL) {
	102	for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
	103	xfree(gss_enc2oid[i].encoded);
	104	xfree(gss_enc2oid);
	105	}
	106
	107	gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping)*
	108	(gss_supported->count + 1));
	109
	110	buffer_init(&buf);
	111
	112	oidpos = 0;
	113	for (i = 0; i < gss_supported->count; i++) {
	114	if (gss_supported->elements[i].length < 128 &&
	115	(*check)(NULL, &(gss_supported->elements[i]), data)) {
116	deroid[0] = SSH_GSS_OIDTYPE;
117	deroid[1] = gss_supported->elements[i].length;
118
119	EVP_DigestInit(&md, evp_md);
120	EVP_DigestUpdate(&md, deroid, 2);
121	EVP_DigestUpdate(&md,
122	gss_supported->elements[i].elements,
123	gss_supported->elements[i].length);
124	EVP_DigestFinal(&md, digest, NULL);
125
126	encoded = xmalloc(EVP_MD_size(evp_md) * 2);
127	enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
128	encoded, EVP_MD_size(evp_md) * 2);
129
130	if (oidpos != 0)
131	buffer_put_char(&buf, ',');
132
133	buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
134	sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
135	buffer_append(&buf, encoded, enclen);
136	buffer_put_char(&buf, ',');
137	buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
138	sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
139	buffer_append(&buf, encoded, enclen);
140	buffer_put_char(&buf, ',');
141	buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
142	sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
143	buffer_append(&buf, encoded, enclen);
144
145	gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
146	gss_enc2oid[oidpos].encoded = encoded;
147	oidpos++;
148	}
149	}
150	gss_enc2oid[oidpos].oid = NULL;
151	gss_enc2oid[oidpos].encoded = NULL;
152
153	buffer_put_char(&buf, '\0');
154
155	mechs = xmalloc(buffer_len(&buf));
156	buffer_get(&buf, mechs, buffer_len(&buf));
157	buffer_free(&buf);
158
159	if (strlen(mechs) == 0) {
160	xfree(mechs);
161	mechs = NULL;
162	}
163
164	return (mechs);
165	}
166
167	gss_OID
168	ssh_gssapi_id_kex(Gssctxt ctx, char name, int kex_type) {
169	int i = 0;
170
171	switch (kex_type) {
172	case KEX_GSS_GRP1_SHA1:
173	name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
174	break;
175	case KEX_GSS_GRP14_SHA1:
176	name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
177	break;
178	case KEX_GSS_GEX_SHA1:
179	name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
180	break;
181	default:
182	return GSS_C_NO_OID;
183	}
184
185	while (gss_enc2oid[i].encoded != NULL &&
186	strcmp(name, gss_enc2oid[i].encoded) != 0)
187	i++;
188
189	if (gss_enc2oid[i].oid != NULL && ctx != NULL)
190	ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
191
192	return gss_enc2oid[i].oid;
193	}
194
0fff78ff	195	/* Check that the OID in a data stream matches that in the context */
	196	int
	197	ssh_gssapi_check_oid(Gssctxt ctx, void data, size_t len)
	198	{
	199	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	200	ctx->oid->length == len &&
	201	memcmp(ctx->oid->elements, data, len) == 0);
	202	}
	203
	204	/* Set the contexts OID from a data stream */
	205	void
	206	ssh_gssapi_set_oid_data(Gssctxt ctx, void data, size_t len)
	207	{
	208	if (ctx->oid != GSS_C_NO_OID) {
	209	xfree(ctx->oid->elements);
	210	xfree(ctx->oid);
	211	}
	212	ctx->oid = xmalloc(sizeof(gss_OID_desc));
	213	ctx->oid->length = len;
	214	ctx->oid->elements = xmalloc(len);
	215	memcpy(ctx->oid->elements, data, len);
	216	}
	217
	218	/* Set the contexts OID */
	219	void
	220	ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
	221	{
	222	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
	223	}
	224
	225	/* All this effort to report an error ... */
	226	void
	227	ssh_gssapi_error(Gssctxt *ctxt)
	228	{
9108f8d9	229	char *s;
	230
	231	s = ssh_gssapi_last_error(ctxt, NULL, NULL);
	232	debug("%s", s);
	233	xfree(s);
0fff78ff	234	}
	235
	236	char *
665a873d	237	ssh_gssapi_last_error(Gssctxt ctxt, OM_uint32 major_status,
665a873d	238	OM_uint32 *minor_status)
0fff78ff	239	{
	240	OM_uint32 lmin;
	241	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	242	OM_uint32 ctx;
	243	Buffer b;
	244	char *ret;
	245
	246	buffer_init(&b);
	247
	248	if (major_status != NULL)
	249	*major_status = ctxt->major;
	250	if (minor_status != NULL)
	251	*minor_status = ctxt->minor;
	252
	253	ctx = 0;
	254	/* The GSSAPI error */
	255	do {
	256	gss_display_status(&lmin, ctxt->major,
659bdb8e	257	GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
0fff78ff	258
	259	buffer_append(&b, msg.value, msg.length);
	260	buffer_put_char(&b, '\n');
	261
	262	gss_release_buffer(&lmin, &msg);
	263	} while (ctx != 0);
	264
	265	/* The mechanism specific error */
	266	do {
	267	gss_display_status(&lmin, ctxt->minor,
659bdb8e	268	GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
0fff78ff	269
	270	buffer_append(&b, msg.value, msg.length);
	271	buffer_put_char(&b, '\n');
	272
	273	gss_release_buffer(&lmin, &msg);
	274	} while (ctx != 0);
	275
	276	buffer_put_char(&b, '\0');
	277	ret = xmalloc(buffer_len(&b));
	278	buffer_get(&b, ret, buffer_len(&b));
	279	buffer_free(&b);
	280	return (ret);
	281	}
	282
	283	/*
	284	* Initialise our GSSAPI context. We use this opaque structure to contain all
	285	* of the data which both the client and server need to persist across
	286	* {accept,init}_sec_context calls, so that when we do it from the userauth
	287	* stuff life is a little easier
	288	*/
	289	void
	290	ssh_gssapi_build_ctx(Gssctxt **ctx)
	291	{
9108f8d9	292	*ctx = xcalloc(1, sizeof (Gssctxt));
0fff78ff	293	(*ctx)->context = GSS_C_NO_CONTEXT;
	294	(*ctx)->name = GSS_C_NO_NAME;
	295	(*ctx)->oid = GSS_C_NO_OID;
	296	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	297	(*ctx)->client = GSS_C_NO_NAME;
	298	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
	299	}
	300
	301	/* Delete our context, providing it has been built correctly */
	302	void
	303	ssh_gssapi_delete_ctx(Gssctxt **ctx)
	304	{
	305	OM_uint32 ms;
	306
	307	if ((*ctx) == NULL)
	308	return;
	309	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	310	gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
	311	if ((*ctx)->name != GSS_C_NO_NAME)
	312	gss_release_name(&ms, &(*ctx)->name);
	313	if ((*ctx)->oid != GSS_C_NO_OID) {
	314	xfree((*ctx)->oid->elements);
	315	xfree((*ctx)->oid);
	316	(*ctx)->oid = GSS_C_NO_OID;
	317	}
	318	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
	319	gss_release_cred(&ms, &(*ctx)->creds);
	320	if ((*ctx)->client != GSS_C_NO_NAME)
	321	gss_release_name(&ms, &(*ctx)->client);
	322	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
	323	gss_release_cred(&ms, &(*ctx)->client_creds);
	324
	325	xfree(*ctx);
	326	*ctx = NULL;
	327	}
	328
	329	/*
	330	* Wrapper to init_sec_context
	331	* Requires that the context contains:
	332	* oid
	333	* server name (from ssh_gssapi_import_name)
	334	*/
	335	OM_uint32
	336	ssh_gssapi_init_ctx(Gssctxt ctx, int deleg_creds, gss_buffer_desc recv_tok,
	337	gss_buffer_desc* send_tok, OM_uint32 *flags)
	338	{
	339	int deleg_flag = 0;
	340
	341	if (deleg_creds) {
	342	deleg_flag = GSS_C_DELEG_FLAG;
	343	debug("Delegating credentials");
	344	}
	345
	346	ctx->major = gss_init_sec_context(&ctx->minor,
	347	GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
	348	GSS_C_MUTUAL_FLAG \| GSS_C_INTEG_FLAG \| deleg_flag,
	349	0, NULL, recv_tok, NULL, send_tok, flags, NULL);
	350
	351	if (GSS_ERROR(ctx->major))
	352	ssh_gssapi_error(ctx);
	353
	354	return (ctx->major);
	355	}
	356
357	/* Create a service name for the given host */
358	OM_uint32
359	ssh_gssapi_import_name(Gssctxt ctx, const char host)
360	{
361	gss_buffer_desc gssbuf;
9108f8d9	362	char *val;
0fff78ff	363
9108f8d9	364	xasprintf(&val, "host@%s", host);
	365	gssbuf.value = val;
	366	gssbuf.length = strlen(gssbuf.value);
0fff78ff	367
	368	if ((ctx->major = gss_import_name(&ctx->minor,
	369	&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
	370	ssh_gssapi_error(ctx);
	371
	372	xfree(gssbuf.value);
	373	return (ctx->major);
	374	}
	375
0fff78ff	376	OM_uint32
659bdb8e	377	ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
0fff78ff	378	{
659bdb8e	379	if (ctx == NULL)
659bdb8e	380	return -1;
0fff78ff	381
659bdb8e	382	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
659bdb8e	383	GSS_C_QOP_DEFAULT, buffer, hash)))
0fff78ff	384	ssh_gssapi_error(ctx);
0fff78ff	385
0fff78ff	386	return (ctx->major);
	387	}
	388
659bdb8e	389	/* Priviledged when used by server */
cdd66111	390	OM_uint32
659bdb8e	391	ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
cdd66111	392	{
659bdb8e	393	if (ctx == NULL)
	394	return -1;
	395
	396	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	397	gssbuf, gssmic, NULL);
cdd66111	398
	399	return (ctx->major);
	400	}
	401
	402	void
	403	ssh_gssapi_buildmic(Buffer b, const char user, const char *service,
	404	const char *context)
	405	{
	406	buffer_init(b);
	407	buffer_put_string(b, session_id2, session_id2_len);
	408	buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
	409	buffer_put_cstring(b, user);
	410	buffer_put_cstring(b, service);
	411	buffer_put_cstring(b, context);
	412	}
	413
9108f8d9	414	int
	415	ssh_gssapi_check_mechanism(Gssctxt *ctx, gss_OID oid, const char host)
	416	{
	417	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
	418	OM_uint32 major, minor;
	419	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
659bdb8e	420	Gssctxt *intctx = NULL;
	421
	422	if (ctx == NULL)
	423	ctx = &intctx;
9108f8d9	424
	425	/* RFC 4462 says we MUST NOT do SPNEGO */
	426	if (oid->length == spnego_oid.length &&
	427	(memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
	428	return 0; /* false */
	429
	430	ssh_gssapi_build_ctx(ctx);
	431	ssh_gssapi_set_oid(*ctx, oid);
	432	major = ssh_gssapi_import_name(*ctx, host);
	433	if (!GSS_ERROR(major)) {
	434	major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
	435	NULL);
	436	gss_release_buffer(&minor, &token);
	437	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	438	gss_delete_sec_context(&minor, &(*ctx)->context,
	439	GSS_C_NO_BUFFER);
	440	}
	441
659bdb8e	442	if (GSS_ERROR(major) \|\| intctx != NULL)
9108f8d9	443	ssh_gssapi_delete_ctx(ctx);
	444
	445	return (!GSS_ERROR(major));
	446	}
	447
0fff78ff	448	#endif /* GSSAPI */