1 /* $OpenBSD: gss-genr.c,v 1.6 2005/10/13 22:24:31 stevesk Exp $ */
4 * Copyright (c) 2001-2005 Simon Wilkinson. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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.
36 #include <openssl/evp.h>
40 extern u_char *session_id2;
41 extern u_int session_id2_len;
46 } ssh_gss_kex_mapping;
49 * XXX - It would be nice to find a more elegant way of handling the
50 * XXX passing of the key exchange context to the userauth routines
53 Gssctxt *gss_kex_context = NULL;
55 static ssh_gss_kex_mapping *gss_enc2oid = NULL;
58 ssh_gssapi_oid_table_ok() {
59 return (gss_enc2oid != NULL);
63 * Return a list of the gss-group1-sha1 mechanisms supported by this program
65 * We test mechanisms to ensure that we can use them, to avoid starting
66 * a key exchange with a bad mechanism
71 ssh_gssapi_client_mechanisms(const char *host) {
72 gss_OID_set gss_supported;
75 gss_indicate_mechs(&min_status, &gss_supported);
77 return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
82 ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
87 char *mechs, *encoded;
88 u_char digest[EVP_MAX_MD_SIZE];
90 const EVP_MD *evp_md = EVP_md5();
93 if (gss_enc2oid != NULL) {
94 for (i=0;gss_enc2oid[i].encoded!=NULL;i++)
95 xfree(gss_enc2oid[i].encoded);
99 gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping)*
100 (gss_supported->count+1));
105 for (i = 0;i < gss_supported->count;i++) {
106 if (gss_supported->elements[i].length < 128 &&
107 (*check)(&(gss_supported->elements[i]), data)) {
109 deroid[0] = SSH_GSS_OIDTYPE;
110 deroid[1] = gss_supported->elements[i].length;
112 EVP_DigestInit(&md, evp_md);
113 EVP_DigestUpdate(&md, deroid, 2);
114 EVP_DigestUpdate(&md,
115 gss_supported->elements[i].elements,
116 gss_supported->elements[i].length);
117 EVP_DigestFinal(&md, digest, NULL);
119 encoded = xmalloc(EVP_MD_size(evp_md)*2);
120 enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
121 encoded, EVP_MD_size(evp_md)*2);
124 buffer_put_char(&buf, ',');
126 buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
127 sizeof(KEX_GSS_GEX_SHA1_ID)-1);
128 buffer_append(&buf, encoded, enclen);
129 buffer_put_char(&buf,',');
130 buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
131 sizeof(KEX_GSS_GRP1_SHA1_ID)-1);
132 buffer_append(&buf, encoded, enclen);
134 gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
135 gss_enc2oid[oidpos].encoded = encoded;
139 gss_enc2oid[oidpos].oid = NULL;
140 gss_enc2oid[oidpos].encoded = NULL;
142 buffer_put_char(&buf, '\0');
144 mechs = xmalloc(buffer_len(&buf));
145 buffer_get(&buf, mechs, buffer_len(&buf));
148 if (strlen(mechs) == 0) {
157 ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int *gex) {
160 if (strncmp(name, KEX_GSS_GRP1_SHA1_ID,
161 sizeof(KEX_GSS_GRP1_SHA1_ID)-1) == 0) {
162 name+=sizeof(KEX_GSS_GRP1_SHA1_ID)-1;
164 } else if (strncmp(name, KEX_GSS_GEX_SHA1_ID,
165 sizeof(KEX_GSS_GEX_SHA1_ID)-1) == 0) {
166 name+=sizeof(KEX_GSS_GEX_SHA1_ID)-1;
172 while (gss_enc2oid[i].encoded != NULL &&
173 strcmp(name, gss_enc2oid[i].encoded) != 0) {
177 if (gss_enc2oid[i].oid != NULL && ctx != NULL)
178 ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
180 return gss_enc2oid[i].oid;
183 /* Check that the OID in a data stream matches that in the context */
185 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
187 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
188 ctx->oid->length == len &&
189 memcmp(ctx->oid->elements, data, len) == 0);
192 /* Set the contexts OID from a data stream */
194 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
196 if (ctx->oid != GSS_C_NO_OID) {
197 xfree(ctx->oid->elements);
200 ctx->oid = xmalloc(sizeof(gss_OID_desc));
201 ctx->oid->length = len;
202 ctx->oid->elements = xmalloc(len);
203 memcpy(ctx->oid->elements, data, len);
206 /* Set the contexts OID */
208 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
210 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
213 /* All this effort to report an error ... */
215 ssh_gssapi_error(Gssctxt *ctxt)
217 debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
221 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
222 OM_uint32 *minor_status)
225 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
232 if (major_status != NULL)
233 *major_status = ctxt->major;
234 if (minor_status != NULL)
235 *minor_status = ctxt->minor;
238 /* The GSSAPI error */
240 gss_display_status(&lmin, ctxt->major,
241 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
243 buffer_append(&b, msg.value, msg.length);
244 buffer_put_char(&b, '\n');
246 gss_release_buffer(&lmin, &msg);
249 /* The mechanism specific error */
251 gss_display_status(&lmin, ctxt->minor,
252 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
254 buffer_append(&b, msg.value, msg.length);
255 buffer_put_char(&b, '\n');
257 gss_release_buffer(&lmin, &msg);
260 buffer_put_char(&b, '\0');
261 ret = xmalloc(buffer_len(&b));
262 buffer_get(&b, ret, buffer_len(&b));
268 * Initialise our GSSAPI context. We use this opaque structure to contain all
269 * of the data which both the client and server need to persist across
270 * {accept,init}_sec_context calls, so that when we do it from the userauth
271 * stuff life is a little easier
274 ssh_gssapi_build_ctx(Gssctxt **ctx)
276 *ctx = xmalloc(sizeof (Gssctxt));
279 (*ctx)->context = GSS_C_NO_CONTEXT;
280 (*ctx)->name = GSS_C_NO_NAME;
281 (*ctx)->oid = GSS_C_NO_OID;
282 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
283 (*ctx)->client = GSS_C_NO_NAME;
284 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
287 /* Delete our context, providing it has been built correctly */
289 ssh_gssapi_delete_ctx(Gssctxt **ctx)
291 #if !defined(MECHGLUE)
297 #if !defined(MECHGLUE) /* mechglue has some memory management issues */
298 if ((*ctx)->context != GSS_C_NO_CONTEXT)
299 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
300 if ((*ctx)->name != GSS_C_NO_NAME)
301 gss_release_name(&ms, &(*ctx)->name);
302 if ((*ctx)->oid != GSS_C_NO_OID) {
303 xfree((*ctx)->oid->elements);
305 (*ctx)->oid = GSS_C_NO_OID;
307 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
308 gss_release_cred(&ms, &(*ctx)->creds);
309 if ((*ctx)->client != GSS_C_NO_NAME)
310 gss_release_name(&ms, &(*ctx)->client);
311 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
312 gss_release_cred(&ms, &(*ctx)->client_creds);
320 * Wrapper to init_sec_context
321 * Requires that the context contains:
323 * server name (from ssh_gssapi_import_name)
326 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
327 gss_buffer_desc* send_tok, OM_uint32 *flags)
332 deleg_flag = GSS_C_DELEG_FLAG;
333 debug("Delegating credentials");
336 ctx->major = gss_init_sec_context(&ctx->minor,
337 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
338 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
339 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
341 if (GSS_ERROR(ctx->major))
342 ssh_gssapi_error(ctx);
347 /* Create a service name for the given host */
349 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
351 gss_buffer_desc gssbuf;
354 /* Make a copy of the host name, in case it was returned by a
355 * previous call to gethostbyname(). */
356 xhost = xstrdup(host);
358 /* Make sure we have the FQDN. Some GSSAPI implementations don't do
359 * this for us themselves */
360 resolve_localhost(&xhost);
362 gssbuf.length = sizeof("host@") + strlen(xhost);
363 gssbuf.value = xmalloc(gssbuf.length);
364 snprintf(gssbuf.value, gssbuf.length, "host@%s", xhost);
366 if ((ctx->major = gss_import_name(&ctx->minor,
367 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
368 ssh_gssapi_error(ctx);
375 /* Acquire credentials for a server running on the current host.
376 * Requires that the context structure contains a valid OID
379 /* Returns a GSSAPI error code */
381 ssh_gssapi_acquire_cred(Gssctxt *ctx)
384 char lname[MAXHOSTNAMELEN];
387 gss_create_empty_oid_set(&status, &oidset);
388 gss_add_oid_set_member(&status, ctx->oid, &oidset);
390 if (gethostname(lname, MAXHOSTNAMELEN))
393 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
396 if ((ctx->major = gss_acquire_cred(&ctx->minor,
397 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
398 ssh_gssapi_error(ctx);
400 gss_release_oid_set(&status, &oidset);
405 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
410 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
411 GSS_C_QOP_DEFAULT, buffer, hash)))
412 ssh_gssapi_error(ctx);
417 /* Priviledged when used by server */
419 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
424 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
425 gssbuf, gssmic, NULL);
431 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
435 buffer_put_string(b, session_id2, session_id2_len);
436 buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
437 buffer_put_cstring(b, user);
438 buffer_put_cstring(b, service);
439 buffer_put_cstring(b, context);
443 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
446 ssh_gssapi_delete_ctx(ctx);
447 ssh_gssapi_build_ctx(ctx);
448 ssh_gssapi_set_oid(*ctx, oid);
449 return (ssh_gssapi_acquire_cred(*ctx));
453 ssh_gssapi_check_mechanism(gss_OID oid, void *host) {
454 Gssctxt * ctx = NULL;
455 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
456 OM_uint32 major, minor;
458 ssh_gssapi_build_ctx(&ctx);
459 ssh_gssapi_set_oid(ctx, oid);
460 ssh_gssapi_import_name(ctx, host);
461 major = ssh_gssapi_init_ctx(ctx, 0, GSS_C_NO_BUFFER, &token, NULL);
462 gss_release_buffer(&minor, &token);
463 ssh_gssapi_delete_ctx(&ctx);
464 return (!GSS_ERROR(major));