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

/* $OpenBSD: gss-genr.c,v 1.19 2007/06/12 11:56:15 dtucker Exp $ */

/*
 * Copyright (c) 2001-2009 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, const char *client) {
	gss_OID_set gss_supported;
	OM_uint32 min_status;

	if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
		return NULL;

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

char *
ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
    const char *host, const char *client) {
	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]), host, client)) {

			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:
		if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
			return GSS_C_NO_OID;
		name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
		break;
	case KEX_GSS_GRP14_SHA1:
		if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
			return GSS_C_NO_OID;
		name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
		break;
	case KEX_GSS_GEX_SHA1:
		if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
			return GSS_C_NO_OID;
		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,
	    ctx->client_creds, &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_client_identity(Gssctxt *ctx, const char *name)
{
	gss_buffer_desc gssbuf;
	gss_name_t gssname;
	OM_uint32 status;
	gss_OID_set oidset;

	gssbuf.value = (void *) name;
	gssbuf.length = strlen(gssbuf.value);

	gss_create_empty_oid_set(&status, &oidset);
	gss_add_oid_set_member(&status, ctx->oid, &oidset);

	ctx->major = gss_import_name(&ctx->minor, &gssbuf,
	    GSS_C_NT_USER_NAME, &gssname);

	if (!ctx->major)
		ctx->major = gss_acquire_cred(&ctx->minor, 
		    gssname, 0, oidset, GSS_C_INITIATE, 
		    &ctx->client_creds, NULL, NULL);

	gss_release_name(&status, &gssname);
	gss_release_oid_set(&status, &oidset);

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

	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, 
    const char *client)
{
	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) && client)
		major = ssh_gssapi_client_identity(*ctx, client);

	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));
}

int
ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
	static gss_name_t saved_name = GSS_C_NO_NAME;
	static OM_uint32 saved_lifetime = 0;
	static gss_OID saved_mech = GSS_C_NO_OID;
	static gss_name_t name;
	static OM_uint32 last_call = 0;
	OM_uint32 lifetime, now, major, minor;
	int equal;
	gss_cred_usage_t usage = GSS_C_INITIATE;
	
	now = time(NULL);

	if (ctxt) {
		debug("Rekey has happened - updating saved versions");

		if (saved_name != GSS_C_NO_NAME)
			gss_release_name(&minor, &saved_name);

		major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
		    &saved_name, &saved_lifetime, NULL, NULL);

		if (!GSS_ERROR(major)) {
			saved_mech = ctxt->oid;
		        saved_lifetime+= now;
		} else {
			/* Handle the error */
		}
		return 0;
	}

	if (now - last_call < 10)
		return 0;

	last_call = now;

	if (saved_mech == GSS_C_NO_OID)
		return 0;
	
	major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL, 
	    &name, &lifetime, NULL, NULL);
	if (major == GSS_S_CREDENTIALS_EXPIRED)
		return 0;
	else if (GSS_ERROR(major))
		return 0;

	major = gss_compare_name(&minor, saved_name, name, &equal);
	gss_release_name(&minor, &name);
	if (GSS_ERROR(major))
		return 0;

	if (equal && (saved_lifetime < lifetime + now - 10))
		return 1;

	return 0;
}

#endif /* GSSAPI */
Commit	Line	Data
d4487008	1	/* $OpenBSD: gss-genr.c,v 1.19 2007/06/12 11:56:15 dtucker Exp $ */
0fff78ff	2
0fff78ff	3	/*
f97edba6	4	* Copyright (c) 2001-2009 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"
f97edba6	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
f97edba6	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, const char client) {
	80	gss_OID_set gss_supported;
	81	OM_uint32 min_status;
	82
	83	if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
	84	return NULL;
	85
	86	return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
	87	host, client));
	88	}
	89
	90	char *
	91	ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
	92	const char host, const char client) {
	93	Buffer buf;
	94	size_t i;
	95	int oidpos, enclen;
	96	char mechs, encoded;
	97	u_char digest[EVP_MAX_MD_SIZE];
	98	char deroid[2];
	99	const EVP_MD *evp_md = EVP_md5();
	100	EVP_MD_CTX md;
	101
	102	if (gss_enc2oid != NULL) {
	103	for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
	104	xfree(gss_enc2oid[i].encoded);
	105	xfree(gss_enc2oid);
	106	}
	107
	108	gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
	109	(gss_supported->count + 1));
	110
	111	buffer_init(&buf);
	112
	113	oidpos = 0;
	114	for (i = 0; i < gss_supported->count; i++) {
	115	if (gss_supported->elements[i].length < 128 &&
116	(*check)(NULL, &(gss_supported->elements[i]), host, client)) {
117
118	deroid[0] = SSH_GSS_OIDTYPE;
119	deroid[1] = gss_supported->elements[i].length;
120
121	EVP_DigestInit(&md, evp_md);
122	EVP_DigestUpdate(&md, deroid, 2);
123	EVP_DigestUpdate(&md,
124	gss_supported->elements[i].elements,
125	gss_supported->elements[i].length);
126	EVP_DigestFinal(&md, digest, NULL);
127
128	encoded = xmalloc(EVP_MD_size(evp_md) * 2);
129	enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
130	encoded, EVP_MD_size(evp_md) * 2);
131
132	if (oidpos != 0)
133	buffer_put_char(&buf, ',');
134
135	buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
136	sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
137	buffer_append(&buf, encoded, enclen);
138	buffer_put_char(&buf, ',');
139	buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
140	sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
141	buffer_append(&buf, encoded, enclen);
142	buffer_put_char(&buf, ',');
143	buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
144	sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
145	buffer_append(&buf, encoded, enclen);
146
147	gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
148	gss_enc2oid[oidpos].encoded = encoded;
149	oidpos++;
150	}
151	}
152	gss_enc2oid[oidpos].oid = NULL;
153	gss_enc2oid[oidpos].encoded = NULL;
154
155	buffer_put_char(&buf, '\0');
156
157	mechs = xmalloc(buffer_len(&buf));
158	buffer_get(&buf, mechs, buffer_len(&buf));
159	buffer_free(&buf);
160
161	if (strlen(mechs) == 0) {
162	xfree(mechs);
163	mechs = NULL;
164	}
165
166	return (mechs);
167	}
168
169	gss_OID
170	ssh_gssapi_id_kex(Gssctxt ctx, char name, int kex_type) {
171	int i = 0;
172
173	switch (kex_type) {
174	case KEX_GSS_GRP1_SHA1:
175	if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
176	return GSS_C_NO_OID;
177	name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
178	break;
179	case KEX_GSS_GRP14_SHA1:
180	if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
181	return GSS_C_NO_OID;
182	name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
183	break;
184	case KEX_GSS_GEX_SHA1:
185	if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
186	return GSS_C_NO_OID;
187	name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
188	break;
189	default:
190	return GSS_C_NO_OID;
191	}
192
193	while (gss_enc2oid[i].encoded != NULL &&
194	strcmp(name, gss_enc2oid[i].encoded) != 0)
195	i++;
196
197	if (gss_enc2oid[i].oid != NULL && ctx != NULL)
198	ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
199
200	return gss_enc2oid[i].oid;
201	}
202
0fff78ff	203	/* Check that the OID in a data stream matches that in the context */
	204	int
	205	ssh_gssapi_check_oid(Gssctxt ctx, void data, size_t len)
	206	{
	207	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	208	ctx->oid->length == len &&
	209	memcmp(ctx->oid->elements, data, len) == 0);
	210	}
	211
	212	/* Set the contexts OID from a data stream */
	213	void
	214	ssh_gssapi_set_oid_data(Gssctxt ctx, void data, size_t len)
	215	{
	216	if (ctx->oid != GSS_C_NO_OID) {
	217	xfree(ctx->oid->elements);
	218	xfree(ctx->oid);
	219	}
	220	ctx->oid = xmalloc(sizeof(gss_OID_desc));
	221	ctx->oid->length = len;
	222	ctx->oid->elements = xmalloc(len);
	223	memcpy(ctx->oid->elements, data, len);
	224	}
	225
	226	/* Set the contexts OID */
	227	void
	228	ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
	229	{
	230	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
	231	}
	232
	233	/* All this effort to report an error ... */
	234	void
	235	ssh_gssapi_error(Gssctxt *ctxt)
	236	{
9108f8d9	237	char *s;
	238
	239	s = ssh_gssapi_last_error(ctxt, NULL, NULL);
	240	debug("%s", s);
	241	xfree(s);
0fff78ff	242	}
	243
	244	char *
665a873d	245	ssh_gssapi_last_error(Gssctxt ctxt, OM_uint32 major_status,
665a873d	246	OM_uint32 *minor_status)
0fff78ff	247	{
	248	OM_uint32 lmin;
	249	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	250	OM_uint32 ctx;
	251	Buffer b;
	252	char *ret;
	253
	254	buffer_init(&b);
	255
	256	if (major_status != NULL)
	257	*major_status = ctxt->major;
	258	if (minor_status != NULL)
	259	*minor_status = ctxt->minor;
	260
	261	ctx = 0;
	262	/* The GSSAPI error */
	263	do {
	264	gss_display_status(&lmin, ctxt->major,
d4487008	265	GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
0fff78ff	266
	267	buffer_append(&b, msg.value, msg.length);
	268	buffer_put_char(&b, '\n');
	269
	270	gss_release_buffer(&lmin, &msg);
	271	} while (ctx != 0);
	272
	273	/* The mechanism specific error */
	274	do {
	275	gss_display_status(&lmin, ctxt->minor,
d4487008	276	GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
0fff78ff	277
	278	buffer_append(&b, msg.value, msg.length);
	279	buffer_put_char(&b, '\n');
	280
	281	gss_release_buffer(&lmin, &msg);
	282	} while (ctx != 0);
	283
	284	buffer_put_char(&b, '\0');
	285	ret = xmalloc(buffer_len(&b));
	286	buffer_get(&b, ret, buffer_len(&b));
	287	buffer_free(&b);
	288	return (ret);
	289	}
	290
	291	/*
	292	* Initialise our GSSAPI context. We use this opaque structure to contain all
	293	* of the data which both the client and server need to persist across
	294	* {accept,init}_sec_context calls, so that when we do it from the userauth
	295	* stuff life is a little easier
	296	*/
	297	void
	298	ssh_gssapi_build_ctx(Gssctxt **ctx)
	299	{
9108f8d9	300	*ctx = xcalloc(1, sizeof (Gssctxt));
0fff78ff	301	(*ctx)->context = GSS_C_NO_CONTEXT;
	302	(*ctx)->name = GSS_C_NO_NAME;
	303	(*ctx)->oid = GSS_C_NO_OID;
	304	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	305	(*ctx)->client = GSS_C_NO_NAME;
	306	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
	307	}
	308
	309	/* Delete our context, providing it has been built correctly */
	310	void
	311	ssh_gssapi_delete_ctx(Gssctxt **ctx)
	312	{
	313	OM_uint32 ms;
	314
	315	if ((*ctx) == NULL)
	316	return;
	317	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	318	gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
	319	if ((*ctx)->name != GSS_C_NO_NAME)
	320	gss_release_name(&ms, &(*ctx)->name);
	321	if ((*ctx)->oid != GSS_C_NO_OID) {
	322	xfree((*ctx)->oid->elements);
	323	xfree((*ctx)->oid);
	324	(*ctx)->oid = GSS_C_NO_OID;
	325	}
	326	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
	327	gss_release_cred(&ms, &(*ctx)->creds);
	328	if ((*ctx)->client != GSS_C_NO_NAME)
	329	gss_release_name(&ms, &(*ctx)->client);
	330	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
	331	gss_release_cred(&ms, &(*ctx)->client_creds);
	332
	333	xfree(*ctx);
	334	*ctx = NULL;
	335	}
	336
	337	/*
	338	* Wrapper to init_sec_context
	339	* Requires that the context contains:
	340	* oid
	341	* server name (from ssh_gssapi_import_name)
	342	*/
	343	OM_uint32
	344	ssh_gssapi_init_ctx(Gssctxt ctx, int deleg_creds, gss_buffer_desc recv_tok,
	345	gss_buffer_desc* send_tok, OM_uint32 *flags)
	346	{
	347	int deleg_flag = 0;
	348
	349	if (deleg_creds) {
	350	deleg_flag = GSS_C_DELEG_FLAG;
	351	debug("Delegating credentials");
	352	}
	353
	354	ctx->major = gss_init_sec_context(&ctx->minor,
f97edba6	355	ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
0fff78ff	356	GSS_C_MUTUAL_FLAG \| GSS_C_INTEG_FLAG \| deleg_flag,
	357	0, NULL, recv_tok, NULL, send_tok, flags, NULL);
	358
	359	if (GSS_ERROR(ctx->major))
	360	ssh_gssapi_error(ctx);
	361
	362	return (ctx->major);
	363	}
	364
	365	/* Create a service name for the given host */
	366	OM_uint32
	367	ssh_gssapi_import_name(Gssctxt ctx, const char host)
	368	{
	369	gss_buffer_desc gssbuf;
9108f8d9	370	char *val;
0fff78ff	371
9108f8d9	372	xasprintf(&val, "host@%s", host);
	373	gssbuf.value = val;
	374	gssbuf.length = strlen(gssbuf.value);
0fff78ff	375
	376	if ((ctx->major = gss_import_name(&ctx->minor,
	377	&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
	378	ssh_gssapi_error(ctx);
	379
	380	xfree(gssbuf.value);
	381	return (ctx->major);
	382	}
	383
f97edba6	384	OM_uint32
	385	ssh_gssapi_client_identity(Gssctxt ctx, const char name)
	386	{
	387	gss_buffer_desc gssbuf;
	388	gss_name_t gssname;
	389	OM_uint32 status;
	390	gss_OID_set oidset;
	391
	392	gssbuf.value = (void *) name;
	393	gssbuf.length = strlen(gssbuf.value);
	394
	395	gss_create_empty_oid_set(&status, &oidset);
	396	gss_add_oid_set_member(&status, ctx->oid, &oidset);
	397
	398	ctx->major = gss_import_name(&ctx->minor, &gssbuf,
	399	GSS_C_NT_USER_NAME, &gssname);
	400
	401	if (!ctx->major)
	402	ctx->major = gss_acquire_cred(&ctx->minor,
	403	gssname, 0, oidset, GSS_C_INITIATE,
	404	&ctx->client_creds, NULL, NULL);
	405
	406	gss_release_name(&status, &gssname);
	407	gss_release_oid_set(&status, &oidset);
	408
	409	if (ctx->major)
	410	ssh_gssapi_error(ctx);
	411
	412	return(ctx->major);
	413	}
	414
cdd66111	415	OM_uint32
	416	ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
	417	{
f97edba6	418	if (ctx == NULL)
	419	return -1;
	420
cdd66111	421	if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
	422	GSS_C_QOP_DEFAULT, buffer, hash)))
	423	ssh_gssapi_error(ctx);
	424
	425	return (ctx->major);
	426	}
	427
f97edba6	428	/* Priviledged when used by server */
	429	OM_uint32
	430	ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
	431	{
	432	if (ctx == NULL)
	433	return -1;
	434
	435	ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
	436	gssbuf, gssmic, NULL);
	437
	438	return (ctx->major);
	439	}
	440
cdd66111	441	void
	442	ssh_gssapi_buildmic(Buffer b, const char user, const char *service,
	443	const char *context)
	444	{
	445	buffer_init(b);
	446	buffer_put_string(b, session_id2, session_id2_len);
	447	buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
	448	buffer_put_cstring(b, user);
	449	buffer_put_cstring(b, service);
	450	buffer_put_cstring(b, context);
	451	}
	452
9108f8d9	453	int
f97edba6	454	ssh_gssapi_check_mechanism(Gssctxt *ctx, gss_OID oid, const char host,
f97edba6	455	const char *client)
9108f8d9	456	{
	457	gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
	458	OM_uint32 major, minor;
	459	gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
f97edba6	460	Gssctxt *intctx = NULL;
	461
	462	if (ctx == NULL)
	463	ctx = &intctx;
9108f8d9	464
	465	/* RFC 4462 says we MUST NOT do SPNEGO */
	466	if (oid->length == spnego_oid.length &&
	467	(memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
	468	return 0; /* false */
	469
	470	ssh_gssapi_build_ctx(ctx);
	471	ssh_gssapi_set_oid(*ctx, oid);
	472	major = ssh_gssapi_import_name(*ctx, host);
f97edba6	473
	474	if (!GSS_ERROR(major) && client)
	475	major = ssh_gssapi_client_identity(*ctx, client);
	476
9108f8d9	477	if (!GSS_ERROR(major)) {
	478	major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
	479	NULL);
	480	gss_release_buffer(&minor, &token);
	481	if ((*ctx)->context != GSS_C_NO_CONTEXT)
	482	gss_delete_sec_context(&minor, &(*ctx)->context,
	483	GSS_C_NO_BUFFER);
	484	}
	485
f97edba6	486	if (GSS_ERROR(major) \|\| intctx != NULL)
9108f8d9	487	ssh_gssapi_delete_ctx(ctx);
	488
	489	return (!GSS_ERROR(major));
	490	}
	491
f97edba6	492	int
	493	ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
	494	static gss_name_t saved_name = GSS_C_NO_NAME;
	495	static OM_uint32 saved_lifetime = 0;
	496	static gss_OID saved_mech = GSS_C_NO_OID;
	497	static gss_name_t name;
	498	static OM_uint32 last_call = 0;
	499	OM_uint32 lifetime, now, major, minor;
	500	int equal;
	501	gss_cred_usage_t usage = GSS_C_INITIATE;
	502
	503	now = time(NULL);
	504
	505	if (ctxt) {
	506	debug("Rekey has happened - updating saved versions");
	507
	508	if (saved_name != GSS_C_NO_NAME)
	509	gss_release_name(&minor, &saved_name);
	510
	511	major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
	512	&saved_name, &saved_lifetime, NULL, NULL);
	513
	514	if (!GSS_ERROR(major)) {
	515	saved_mech = ctxt->oid;
	516	saved_lifetime+= now;
	517	} else {
	518	/* Handle the error */
	519	}
	520	return 0;
	521	}
	522
	523	if (now - last_call < 10)
	524	return 0;
	525
	526	last_call = now;
	527
	528	if (saved_mech == GSS_C_NO_OID)
	529	return 0;
	530
	531	major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
	532	&name, &lifetime, NULL, NULL);
	533	if (major == GSS_S_CREDENTIALS_EXPIRED)
	534	return 0;
	535	else if (GSS_ERROR(major))
	536	return 0;
	537
	538	major = gss_compare_name(&minor, saved_name, name, &equal);
	539	gss_release_name(&minor, &name);
	540	if (GSS_ERROR(major))
	541	return 0;
	542
	543	if (equal && (saved_lifetime < lifetime + now - 10))
	544	return 1;
	545
	546	return 0;
	547	}
	548
0fff78ff	549	#endif /* GSSAPI */