[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"
70e5f740	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
70e5f740	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
117	deroid[0] = SSH_GSS_OIDTYPE;
118	deroid[1] = gss_supported->elements[i].length;
119
120	EVP_DigestInit(&md, evp_md);
121	EVP_DigestUpdate(&md, deroid, 2);
122	EVP_DigestUpdate(&md,
123	gss_supported->elements[i].elements,
124	gss_supported->elements[i].length);
125	EVP_DigestFinal(&md, digest, NULL);
126
127	encoded = xmalloc(EVP_MD_size(evp_md) * 2);
128	enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
129	encoded, EVP_MD_size(evp_md) * 2);
130
131	if (oidpos != 0)
132	buffer_put_char(&buf, ',');
133
134	buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
135	sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
136	buffer_append(&buf, encoded, enclen);
137	buffer_put_char(&buf, ',');
138	buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
139	sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
140	buffer_append(&buf, encoded, enclen);
141	buffer_put_char(&buf, ',');
142	buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
143	sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
144	buffer_append(&buf, encoded, enclen);
145
146	gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
147	gss_enc2oid[oidpos].encoded = encoded;
148	oidpos++;
149	}
150	}
151	gss_enc2oid[oidpos].oid = NULL;
152	gss_enc2oid[oidpos].encoded = NULL;
153
154	buffer_put_char(&buf, '\0');
155
156	mechs = xmalloc(buffer_len(&buf));
157	buffer_get(&buf, mechs, buffer_len(&buf));
158	buffer_free(&buf);
159
160	if (strlen(mechs) == 0) {
161	xfree(mechs);
162	mechs = NULL;
163	}
164
165	return (mechs);
166	}
167
168	gss_OID
169	ssh_gssapi_id_kex(Gssctxt ctx, char name, int kex_type) {
170	int i = 0;
171
172	switch (kex_type) {
173	case KEX_GSS_GRP1_SHA1:
174	name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
175	break;
176	case KEX_GSS_GRP14_SHA1:
177	name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
178	break;
179	case KEX_GSS_GEX_SHA1:
180	name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
181	break;
182	default:
183	return GSS_C_NO_OID;
184	}
185
186	while (gss_enc2oid[i].encoded != NULL &&
187	strcmp(name, gss_enc2oid[i].encoded) != 0)
188	i++;
189
190	if (gss_enc2oid[i].oid != NULL && ctx != NULL)
191	ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
192
193	return gss_enc2oid[i].oid;
194	}
195
0fff78ff	196	/* Check that the OID in a data stream matches that in the context */
	197	int
	198	ssh_gssapi_check_oid(Gssctxt ctx, void data, size_t len)
	199	{
	200	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	201	ctx->oid->length == len &&
	202	memcmp(ctx->oid->elements, data, len) == 0);
	203	}
	204
	205	/* Set the contexts OID from a data stream */
	206	void
	207	ssh_gssapi_set_oid_data(Gssctxt ctx, void data, size_t len)
	208	{
	209	if (ctx->oid != GSS_C_NO_OID) {
	210	xfree(ctx->oid->elements);
	211	xfree(ctx->oid);
	212	}
	213	ctx->oid = xmalloc(sizeof(gss_OID_desc));
	214	ctx->oid->length = len;
	215	ctx->oid->elements = xmalloc(len);
	216	memcpy(ctx->oid->elements, data, len);
	217	}
	218
	219	/* Set the contexts OID */
	220	void
	221	ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
	222	{
	223	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
	224	}
	225
	226	/* All this effort to report an error ... */
	227	void
	228	ssh_gssapi_error(Gssctxt *ctxt)
	229	{
9108f8d9	230	char *s;
	231
	232	s = ssh_gssapi_last_error(ctxt, NULL, NULL);
	233	debug("%s", s);
	234	xfree(s);
0fff78ff	235	}
	236
	237	char *
665a873d	238	ssh_gssapi_last_error(Gssctxt ctxt, OM_uint32 major_status,
665a873d	239	OM_uint32 *minor_status)
0fff78ff	240	{
	241	OM_uint32 lmin;
	242	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	243	OM_uint32 ctx;
	244	Buffer b;
	245	char *ret;
	246
	247	buffer_init(&b);
	248
	249	if (major_status != NULL)
	250	*major_status = ctxt->major;
	251	if (minor_status != NULL)
	252	*minor_status = ctxt->minor;
	253
	254	ctx = 0;
	255	/* The GSSAPI error */
	256	do {
	257	gss_display_status(&lmin, ctxt->major,
70e5f740	258	GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
0fff78ff	259
	260	buffer_append(&b, msg.value, msg.length);
	261	buffer_put_char(&b, '\n');
	262
	263	gss_release_buffer(&lmin, &msg);
	264	} while (ctx != 0);
	265
	266	/* The mechanism specific error */
	267	do {
	268	gss_display_status(&lmin, ctxt->minor,
70e5f740	269	GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
0fff78ff	270
	271	buffer_append(&b, msg.value, msg.length);
	272	buffer_put_char(&b, '\n');
	273
	274	gss_release_buffer(&lmin, &msg);
	275	} while (ctx != 0);
	276
	277	buffer_put_char(&b, '\0');
	278	ret = xmalloc(buffer_len(&b));
	279	buffer_get(&b, ret, buffer_len(&b));
	280	buffer_free(&b);
	281	return (ret);
	282	}
	283
	284	/*
	285	* Initialise our GSSAPI context. We use this opaque structure to contain all
	286	* of the data which both the client and server need to persist across
	287	* {accept,init}_sec_context calls, so that when we do it from the userauth
	288	* stuff life is a little easier
	289	*/
	290	void
	291	ssh_gssapi_build_ctx(Gssctxt **ctx)
	292	{
9108f8d9	293	*ctx = xcalloc(1, sizeof (Gssctxt));
0fff78ff	294	(*ctx)->context = GSS_C_NO_CONTEXT;
	295	(*ctx)->name = GSS_C_NO_NAME;
	296	(*ctx)->oid = GSS_C_NO_OID;
	297	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	298	(*ctx)->client = GSS_C_NO_NAME;
	299	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
	300	}
	301
	302	/* Delete our context, providing it has been built correctly */
	303	void
	304	ssh_gssapi_delete_ctx(Gssctxt **ctx)
	305	{
	306	OM_uint32 ms;
	307
	308	if ((*ctx) == NULL)
	309	return;
	310	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	311	gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
	312	if ((*ctx)->name != GSS_C_NO_NAME)
	313	gss_release_name(&ms, &(*ctx)->name);
	314	if ((*ctx)->oid != GSS_C_NO_OID) {
	315	xfree((*ctx)->oid->elements);
	316	xfree((*ctx)->oid);
	317	(*ctx)->oid = GSS_C_NO_OID;
	318	}
	319	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
	320	gss_release_cred(&ms, &(*ctx)->creds);
	321	if ((*ctx)->client != GSS_C_NO_NAME)
	322	gss_release_name(&ms, &(*ctx)->client);
	323	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
	324	gss_release_cred(&ms, &(*ctx)->client_creds);
	325
	326	xfree(*ctx);
	327	*ctx = NULL;
	328	}
	329
	330	/*
	331	* Wrapper to init_sec_context
	332	* Requires that the context contains:
	333	* oid
	334	* server name (from ssh_gssapi_import_name)
	335	*/
	336	OM_uint32
	337	ssh_gssapi_init_ctx(Gssctxt ctx, int deleg_creds, gss_buffer_desc recv_tok,
	338	gss_buffer_desc* send_tok, OM_uint32 *flags)
	339	{
	340	int deleg_flag = 0;
	341
	342	if (deleg_creds) {
	343	deleg_flag = GSS_C_DELEG_FLAG;
	344	debug("Delegating credentials");
	345	}
	346
	347	ctx->major = gss_init_sec_context(&ctx->minor,
	348	GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
	349	GSS_C_MUTUAL_FLAG \| GSS_C_INTEG_FLAG \| deleg_flag,
	350	0, NULL, recv_tok, NULL, send_tok, flags, NULL);
	351
	352	if (GSS_ERROR(ctx->major))
	353	ssh_gssapi_error(ctx);
	354
	355	return (ctx->major);
	356	}
	357
358	/* Create a service name for the given host */
359	OM_uint32
360	ssh_gssapi_import_name(Gssctxt ctx, const char host)
361	{
362	gss_buffer_desc gssbuf;
9108f8d9	363	char *val;
0fff78ff	364
9108f8d9	365	xasprintf(&val, "host@%s", host);
	366	gssbuf.value = val;
	367	gssbuf.length = strlen(gssbuf.value);
0fff78ff	368
	369	if ((ctx->major = gss_import_name(&ctx->minor,
	370	&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
	371	ssh_gssapi_error(ctx);
	372
	373	xfree(gssbuf.value);
	374	return (ctx->major);
	375	}
	376
0fff78ff	377	OM_uint32
70e5f740	378	ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
0fff78ff	379	{
70e5f740	380	if (ctx == NULL)
70e5f740	381	return -1;
0fff78ff	382
70e5f740	383	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
70e5f740	384	GSS_C_QOP_DEFAULT, buffer, hash)))
0fff78ff	385	ssh_gssapi_error(ctx);
0fff78ff	386
0fff78ff	387	return (ctx->major);
	388	}
	389
70e5f740	390	/* Priviledged when used by server */
cdd66111	391	OM_uint32
70e5f740	392	ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
cdd66111	393	{
70e5f740	394	if (ctx == NULL)
	395	return -1;
	396
	397	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	398	gssbuf, gssmic, NULL);
cdd66111	399
	400	return (ctx->major);
	401	}
	402
	403	void
	404	ssh_gssapi_buildmic(Buffer b, const char user, const char *service,
	405	const char *context)
	406	{
	407	buffer_init(b);
	408	buffer_put_string(b, session_id2, session_id2_len);
	409	buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
	410	buffer_put_cstring(b, user);
	411	buffer_put_cstring(b, service);
	412	buffer_put_cstring(b, context);
	413	}
	414
9108f8d9	415	int
	416	ssh_gssapi_check_mechanism(Gssctxt *ctx, gss_OID oid, const char host)
	417	{
	418	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
	419	OM_uint32 major, minor;
	420	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
70e5f740	421	Gssctxt *intctx = NULL;
	422
	423	if (ctx == NULL)
	424	ctx = &intctx;
9108f8d9	425
	426	/* RFC 4462 says we MUST NOT do SPNEGO */
	427	if (oid->length == spnego_oid.length &&
	428	(memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
	429	return 0; /* false */
	430
	431	ssh_gssapi_build_ctx(ctx);
	432	ssh_gssapi_set_oid(*ctx, oid);
	433	major = ssh_gssapi_import_name(*ctx, host);
	434	if (!GSS_ERROR(major)) {
	435	major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
	436	NULL);
	437	gss_release_buffer(&minor, &token);
	438	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	439	gss_delete_sec_context(&minor, &(*ctx)->context,
	440	GSS_C_NO_BUFFER);
	441	}
	442
70e5f740	443	if (GSS_ERROR(major) \|\| intctx != NULL)
9108f8d9	444	ssh_gssapi_delete_ctx(ctx);
	445
	446	return (!GSS_ERROR(major));
	447	}
	448
0fff78ff	449	#endif /* GSSAPI */