1 /* $OpenBSD: gss-genr.c,v 1.19 2007/06/12 11:56:15 dtucker Exp $ */
4 * Copyright (c) 2001-2009 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.
31 #include <sys/types.h>
32 #include <sys/param.h>
46 #include <openssl/evp.h>
50 extern u_char *session_id2;
51 extern u_int session_id2_len;
56 } ssh_gss_kex_mapping;
59 * XXX - It would be nice to find a more elegant way of handling the
60 * XXX passing of the key exchange context to the userauth routines
63 Gssctxt *gss_kex_context = NULL;
65 static ssh_gss_kex_mapping *gss_enc2oid = NULL;
68 ssh_gssapi_oid_table_ok() {
69 return (gss_enc2oid != NULL);
73 * Return a list of the gss-group1-sha1 mechanisms supported by this program
75 * We test mechanisms to ensure that we can use them, to avoid starting
76 * a key exchange with a bad mechanism
80 ssh_gssapi_client_mechanisms(const char *host, const char *client) {
81 gss_OID_set gss_supported;
84 if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
87 return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
92 ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
93 const char *host, const char *client) {
97 char *mechs, *encoded;
98 u_char digest[EVP_MAX_MD_SIZE];
100 const EVP_MD *evp_md = EVP_md5();
103 if (gss_enc2oid != NULL) {
104 for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
105 xfree(gss_enc2oid[i].encoded);
109 gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
110 (gss_supported->count + 1));
115 for (i = 0; i < gss_supported->count; i++) {
116 if (gss_supported->elements[i].length < 128 &&
117 (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
119 deroid[0] = SSH_GSS_OIDTYPE;
120 deroid[1] = gss_supported->elements[i].length;
122 EVP_DigestInit(&md, evp_md);
123 EVP_DigestUpdate(&md, deroid, 2);
124 EVP_DigestUpdate(&md,
125 gss_supported->elements[i].elements,
126 gss_supported->elements[i].length);
127 EVP_DigestFinal(&md, digest, NULL);
129 encoded = xmalloc(EVP_MD_size(evp_md) * 2);
130 enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
131 encoded, EVP_MD_size(evp_md) * 2);
134 buffer_put_char(&buf, ',');
136 buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
137 sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
138 buffer_append(&buf, encoded, enclen);
139 buffer_put_char(&buf, ',');
140 buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
141 sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
142 buffer_append(&buf, encoded, enclen);
143 buffer_put_char(&buf, ',');
144 buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
145 sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
146 buffer_append(&buf, encoded, enclen);
148 gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
149 gss_enc2oid[oidpos].encoded = encoded;
153 gss_enc2oid[oidpos].oid = NULL;
154 gss_enc2oid[oidpos].encoded = NULL;
156 buffer_put_char(&buf, '\0');
158 mechs = xmalloc(buffer_len(&buf));
159 buffer_get(&buf, mechs, buffer_len(&buf));
162 if (strlen(mechs) == 0) {
171 ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
175 case KEX_GSS_GRP1_SHA1:
176 if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
178 name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
180 case KEX_GSS_GRP14_SHA1:
181 if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
183 name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
185 case KEX_GSS_GEX_SHA1:
186 if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
188 name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
194 while (gss_enc2oid[i].encoded != NULL &&
195 strcmp(name, gss_enc2oid[i].encoded) != 0)
198 if (gss_enc2oid[i].oid != NULL && ctx != NULL)
199 ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
201 return gss_enc2oid[i].oid;
204 /* Check that the OID in a data stream matches that in the context */
206 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
208 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
209 ctx->oid->length == len &&
210 memcmp(ctx->oid->elements, data, len) == 0);
213 /* Set the contexts OID from a data stream */
215 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
217 if (ctx->oid != GSS_C_NO_OID) {
218 xfree(ctx->oid->elements);
221 ctx->oid = xmalloc(sizeof(gss_OID_desc));
222 ctx->oid->length = len;
223 ctx->oid->elements = xmalloc(len);
224 memcpy(ctx->oid->elements, data, len);
227 /* Set the contexts OID */
229 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
231 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
234 /* All this effort to report an error ... */
236 ssh_gssapi_error(Gssctxt *ctxt)
240 s = ssh_gssapi_last_error(ctxt, NULL, NULL);
246 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
247 OM_uint32 *minor_status)
250 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
257 if (major_status != NULL)
258 *major_status = ctxt->major;
259 if (minor_status != NULL)
260 *minor_status = ctxt->minor;
263 /* The GSSAPI error */
265 gss_display_status(&lmin, ctxt->major,
266 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
268 buffer_append(&b, msg.value, msg.length);
269 buffer_put_char(&b, '\n');
271 gss_release_buffer(&lmin, &msg);
274 /* The mechanism specific error */
276 gss_display_status(&lmin, ctxt->minor,
277 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
279 buffer_append(&b, msg.value, msg.length);
280 buffer_put_char(&b, '\n');
282 gss_release_buffer(&lmin, &msg);
285 buffer_put_char(&b, '\0');
286 ret = xmalloc(buffer_len(&b));
287 buffer_get(&b, ret, buffer_len(&b));
293 * Initialise our GSSAPI context. We use this opaque structure to contain all
294 * of the data which both the client and server need to persist across
295 * {accept,init}_sec_context calls, so that when we do it from the userauth
296 * stuff life is a little easier
299 ssh_gssapi_build_ctx(Gssctxt **ctx)
301 *ctx = xcalloc(1, sizeof (Gssctxt));
302 (*ctx)->context = GSS_C_NO_CONTEXT;
303 (*ctx)->name = GSS_C_NO_NAME;
304 (*ctx)->oid = GSS_C_NO_OID;
305 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
306 (*ctx)->client = GSS_C_NO_NAME;
307 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
310 /* Delete our context, providing it has been built correctly */
312 ssh_gssapi_delete_ctx(Gssctxt **ctx)
314 #if !defined(MECHGLUE)
320 #if !defined(MECHGLUE) /* mechglue has some memory management issues */
321 if ((*ctx)->context != GSS_C_NO_CONTEXT)
322 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
323 if ((*ctx)->name != GSS_C_NO_NAME)
324 gss_release_name(&ms, &(*ctx)->name);
325 if ((*ctx)->oid != GSS_C_NO_OID) {
326 xfree((*ctx)->oid->elements);
328 (*ctx)->oid = GSS_C_NO_OID;
330 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
331 gss_release_cred(&ms, &(*ctx)->creds);
332 if ((*ctx)->client != GSS_C_NO_NAME)
333 gss_release_name(&ms, &(*ctx)->client);
334 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
335 gss_release_cred(&ms, &(*ctx)->client_creds);
343 * Wrapper to init_sec_context
344 * Requires that the context contains:
346 * server name (from ssh_gssapi_import_name)
349 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
350 gss_buffer_desc* send_tok, OM_uint32 *flags)
355 deleg_flag = GSS_C_DELEG_FLAG;
356 debug("Delegating credentials");
359 ctx->major = gss_init_sec_context(&ctx->minor,
360 ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
361 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
362 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
364 if (GSS_ERROR(ctx->major))
365 ssh_gssapi_error(ctx);
370 /* Create a service name for the given host */
372 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
374 gss_buffer_desc gssbuf;
378 /* Make a copy of the host name, in case it was returned by a
379 * previous call to gethostbyname(). */
380 xhost = xstrdup(host);
382 /* Make sure we have the FQDN. Some GSSAPI implementations don't do
383 * this for us themselves */
384 resolve_localhost(&xhost);
386 xasprintf(&val, "host@%s", xhost);
388 gssbuf.length = strlen(gssbuf.value);
390 if ((ctx->major = gss_import_name(&ctx->minor,
391 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
392 ssh_gssapi_error(ctx);
400 ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
402 gss_buffer_desc gssbuf;
407 gssbuf.value = (void *) name;
408 gssbuf.length = strlen(gssbuf.value);
410 gss_create_empty_oid_set(&status, &oidset);
411 gss_add_oid_set_member(&status, ctx->oid, &oidset);
413 ctx->major = gss_import_name(&ctx->minor, &gssbuf,
414 GSS_C_NT_USER_NAME, &gssname);
417 ctx->major = gss_acquire_cred(&ctx->minor,
418 gssname, 0, oidset, GSS_C_INITIATE,
419 &ctx->client_creds, NULL, NULL);
421 gss_release_name(&status, &gssname);
422 gss_release_oid_set(&status, &oidset);
425 ssh_gssapi_error(ctx);
431 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
436 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
437 GSS_C_QOP_DEFAULT, buffer, hash)))
438 ssh_gssapi_error(ctx);
443 /* Priviledged when used by server */
445 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
450 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
451 gssbuf, gssmic, NULL);
457 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
461 buffer_put_string(b, session_id2, session_id2_len);
462 buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
463 buffer_put_cstring(b, user);
464 buffer_put_cstring(b, service);
465 buffer_put_cstring(b, context);
469 ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
472 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
473 OM_uint32 major, minor;
474 gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
475 Gssctxt *intctx = NULL;
480 /* RFC 4462 says we MUST NOT do SPNEGO */
481 if (oid->length == spnego_oid.length &&
482 (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
483 return 0; /* false */
485 ssh_gssapi_build_ctx(ctx);
486 ssh_gssapi_set_oid(*ctx, oid);
487 major = ssh_gssapi_import_name(*ctx, host);
489 if (!GSS_ERROR(major) && client)
490 major = ssh_gssapi_client_identity(*ctx, client);
492 if (!GSS_ERROR(major)) {
493 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
495 gss_release_buffer(&minor, &token);
496 if ((*ctx)->context != GSS_C_NO_CONTEXT)
497 gss_delete_sec_context(&minor, &(*ctx)->context,
501 if (GSS_ERROR(major) || intctx != NULL)
502 ssh_gssapi_delete_ctx(ctx);
504 return (!GSS_ERROR(major));
508 ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
509 static gss_name_t saved_name = GSS_C_NO_NAME;
510 static OM_uint32 saved_lifetime = 0;
511 static gss_OID saved_mech = GSS_C_NO_OID;
512 static gss_name_t name;
513 static OM_uint32 last_call = 0;
514 OM_uint32 lifetime, now, major, minor;
516 gss_cred_usage_t usage = GSS_C_INITIATE;
521 debug("Rekey has happened - updating saved versions");
523 if (saved_name != GSS_C_NO_NAME)
524 gss_release_name(&minor, &saved_name);
526 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
527 &saved_name, &saved_lifetime, NULL, NULL);
529 if (!GSS_ERROR(major)) {
530 saved_mech = ctxt->oid;
531 saved_lifetime+= now;
533 /* Handle the error */
538 if (now - last_call < 10)
543 if (saved_mech == GSS_C_NO_OID)
546 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
547 &name, &lifetime, NULL, NULL);
548 if (major == GSS_S_CREDENTIALS_EXPIRED)
550 else if (GSS_ERROR(major))
553 major = gss_compare_name(&minor, saved_name, name, &equal);
554 gss_release_name(&minor, &name);
555 if (GSS_ERROR(major))
558 if (equal && (saved_lifetime < lifetime + now - 10))