1 /* $OpenBSD: gss-genr.c,v 1.20 2009/06/22 05:39:28 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>
45 #include <openssl/evp.h>
49 extern u_char *session_id2;
50 extern u_int session_id2_len;
55 } ssh_gss_kex_mapping;
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
62 Gssctxt *gss_kex_context = NULL;
64 static ssh_gss_kex_mapping *gss_enc2oid = NULL;
67 ssh_gssapi_oid_table_ok() {
68 return (gss_enc2oid != NULL);
72 * Return a list of the gss-group1-sha1 mechanisms supported by this program
74 * We test mechanisms to ensure that we can use them, to avoid starting
75 * a key exchange with a bad mechanism
79 ssh_gssapi_client_mechanisms(const char *host, const char *client) {
80 gss_OID_set gss_supported;
83 if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
86 return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
91 ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
92 const char *host, const char *client) {
96 char *mechs, *encoded;
97 u_char digest[EVP_MAX_MD_SIZE];
99 const EVP_MD *evp_md = EVP_md5();
102 if (gss_enc2oid != NULL) {
103 for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
104 xfree(gss_enc2oid[i].encoded);
108 gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
109 (gss_supported->count + 1));
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)) {
118 deroid[0] = SSH_GSS_OIDTYPE;
119 deroid[1] = gss_supported->elements[i].length;
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);
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);
133 buffer_put_char(&buf, ',');
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);
147 gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
148 gss_enc2oid[oidpos].encoded = encoded;
152 gss_enc2oid[oidpos].oid = NULL;
153 gss_enc2oid[oidpos].encoded = NULL;
155 buffer_put_char(&buf, '\0');
157 mechs = xmalloc(buffer_len(&buf));
158 buffer_get(&buf, mechs, buffer_len(&buf));
161 if (strlen(mechs) == 0) {
170 ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
174 case KEX_GSS_GRP1_SHA1:
175 if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
177 name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
179 case KEX_GSS_GRP14_SHA1:
180 if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
182 name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
184 case KEX_GSS_GEX_SHA1:
185 if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
187 name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
193 while (gss_enc2oid[i].encoded != NULL &&
194 strcmp(name, gss_enc2oid[i].encoded) != 0)
197 if (gss_enc2oid[i].oid != NULL && ctx != NULL)
198 ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
200 return gss_enc2oid[i].oid;
203 /* Check that the OID in a data stream matches that in the context */
205 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
207 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
208 ctx->oid->length == len &&
209 memcmp(ctx->oid->elements, data, len) == 0);
212 /* Set the contexts OID from a data stream */
214 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
216 if (ctx->oid != GSS_C_NO_OID) {
217 xfree(ctx->oid->elements);
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);
226 /* Set the contexts OID */
228 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
230 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
233 /* All this effort to report an error ... */
235 ssh_gssapi_error(Gssctxt *ctxt)
239 s = ssh_gssapi_last_error(ctxt, NULL, NULL);
245 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
246 OM_uint32 *minor_status)
249 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
256 if (major_status != NULL)
257 *major_status = ctxt->major;
258 if (minor_status != NULL)
259 *minor_status = ctxt->minor;
262 /* The GSSAPI error */
264 gss_display_status(&lmin, ctxt->major,
265 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
267 buffer_append(&b, msg.value, msg.length);
268 buffer_put_char(&b, '\n');
270 gss_release_buffer(&lmin, &msg);
273 /* The mechanism specific error */
275 gss_display_status(&lmin, ctxt->minor,
276 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
278 buffer_append(&b, msg.value, msg.length);
279 buffer_put_char(&b, '\n');
281 gss_release_buffer(&lmin, &msg);
284 buffer_put_char(&b, '\0');
285 ret = xmalloc(buffer_len(&b));
286 buffer_get(&b, ret, buffer_len(&b));
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
298 ssh_gssapi_build_ctx(Gssctxt **ctx)
300 *ctx = xcalloc(1, sizeof (Gssctxt));
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;
309 /* Delete our context, providing it has been built correctly */
311 ssh_gssapi_delete_ctx(Gssctxt **ctx)
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);
324 (*ctx)->oid = GSS_C_NO_OID;
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);
338 * Wrapper to init_sec_context
339 * Requires that the context contains:
341 * server name (from ssh_gssapi_import_name)
344 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
345 gss_buffer_desc* send_tok, OM_uint32 *flags)
350 deleg_flag = GSS_C_DELEG_FLAG;
351 debug("Delegating credentials");
354 ctx->major = gss_init_sec_context(&ctx->minor,
355 ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
356 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
357 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
359 if (GSS_ERROR(ctx->major))
360 ssh_gssapi_error(ctx);
365 /* Create a service name for the given host */
367 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
369 gss_buffer_desc gssbuf;
372 xasprintf(&val, "host@%s", host);
374 gssbuf.length = strlen(gssbuf.value);
376 if ((ctx->major = gss_import_name(&ctx->minor,
377 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
378 ssh_gssapi_error(ctx);
385 ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
387 gss_buffer_desc gssbuf;
392 gssbuf.value = (void *) name;
393 gssbuf.length = strlen(gssbuf.value);
395 gss_create_empty_oid_set(&status, &oidset);
396 gss_add_oid_set_member(&status, ctx->oid, &oidset);
398 ctx->major = gss_import_name(&ctx->minor, &gssbuf,
399 GSS_C_NT_USER_NAME, &gssname);
402 ctx->major = gss_acquire_cred(&ctx->minor,
403 gssname, 0, oidset, GSS_C_INITIATE,
404 &ctx->client_creds, NULL, NULL);
406 gss_release_name(&status, &gssname);
407 gss_release_oid_set(&status, &oidset);
410 ssh_gssapi_error(ctx);
416 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
421 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
422 GSS_C_QOP_DEFAULT, buffer, hash)))
423 ssh_gssapi_error(ctx);
428 /* Priviledged when used by server */
430 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
435 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
436 gssbuf, gssmic, NULL);
442 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
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);
454 ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
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"};
460 Gssctxt *intctx = NULL;
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 */
470 ssh_gssapi_build_ctx(ctx);
471 ssh_gssapi_set_oid(*ctx, oid);
472 major = ssh_gssapi_import_name(*ctx, host);
474 if (!GSS_ERROR(major) && client)
475 major = ssh_gssapi_client_identity(*ctx, client);
477 if (!GSS_ERROR(major)) {
478 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
480 gss_release_buffer(&minor, &token);
481 if ((*ctx)->context != GSS_C_NO_CONTEXT)
482 gss_delete_sec_context(&minor, &(*ctx)->context,
486 if (GSS_ERROR(major) || intctx != NULL)
487 ssh_gssapi_delete_ctx(ctx);
489 return (!GSS_ERROR(major));
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;
501 gss_cred_usage_t usage = GSS_C_INITIATE;
506 debug("Rekey has happened - updating saved versions");
508 if (saved_name != GSS_C_NO_NAME)
509 gss_release_name(&minor, &saved_name);
511 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
512 &saved_name, &saved_lifetime, NULL, NULL);
514 if (!GSS_ERROR(major)) {
515 saved_mech = ctxt->oid;
516 saved_lifetime+= now;
518 /* Handle the error */
523 if (now - last_call < 10)
528 if (saved_mech == GSS_C_NO_OID)
531 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
532 &name, &lifetime, NULL, NULL);
533 if (major == GSS_S_CREDENTIALS_EXPIRED)
535 else if (GSS_ERROR(major))
538 major = gss_compare_name(&minor, saved_name, name, &equal);
539 gss_release_name(&minor, &name);
540 if (GSS_ERROR(major))
543 if (equal && (saved_lifetime < lifetime + now - 10))