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>
48 #include <openssl/evp.h>
52 extern u_char *session_id2;
53 extern u_int session_id2_len;
54 extern Options options;
59 } ssh_gss_kex_mapping;
62 * XXX - It would be nice to find a more elegant way of handling the
63 * XXX passing of the key exchange context to the userauth routines
66 Gssctxt *gss_kex_context = NULL;
68 static ssh_gss_kex_mapping *gss_enc2oid = NULL;
70 static char *gss_password = NULL;
73 ssh_gssapi_cleanup_password(void)
76 memset(gss_password, 0, strlen(gss_password));
82 ssh_gssapi_oid_table_ok() {
83 return (gss_enc2oid != NULL);
87 * Return a list of the gss-group1-sha1 mechanisms supported by this program
89 * We test mechanisms to ensure that we can use them, to avoid starting
90 * a key exchange with a bad mechanism
94 ssh_gssapi_client_mechanisms(const char *host, const char *client) {
95 gss_OID_set gss_supported;
96 OM_uint32 maj_status, min_status;
98 if (options.gss_mechanism_oid) {
99 maj_status = gss_create_empty_oid_set(&min_status,
101 if (!GSS_ERROR(maj_status))
102 maj_status = gss_add_oid_set_member(&min_status,
103 options.gss_mechanism_oid,
106 maj_status = gss_indicate_mechs(&min_status, &gss_supported);
109 if (GSS_ERROR(maj_status))
112 return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
117 ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
118 const char *host, const char *client) {
122 char *mechs, *encoded;
123 u_char digest[EVP_MAX_MD_SIZE];
125 const EVP_MD *evp_md = EVP_md5();
128 if (gss_enc2oid != NULL) {
129 for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
130 xfree(gss_enc2oid[i].encoded);
134 gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
135 (gss_supported->count + 1));
140 for (i = 0; i < gss_supported->count; i++) {
141 if (gss_supported->elements[i].length < 128 &&
142 (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
144 deroid[0] = SSH_GSS_OIDTYPE;
145 deroid[1] = gss_supported->elements[i].length;
147 EVP_DigestInit(&md, evp_md);
148 EVP_DigestUpdate(&md, deroid, 2);
149 EVP_DigestUpdate(&md,
150 gss_supported->elements[i].elements,
151 gss_supported->elements[i].length);
152 EVP_DigestFinal(&md, digest, NULL);
154 encoded = xmalloc(EVP_MD_size(evp_md) * 2);
155 enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
156 encoded, EVP_MD_size(evp_md) * 2);
159 buffer_put_char(&buf, ',');
161 buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
162 sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
163 buffer_append(&buf, encoded, enclen);
164 buffer_put_char(&buf, ',');
165 buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
166 sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
167 buffer_append(&buf, encoded, enclen);
168 buffer_put_char(&buf, ',');
169 buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
170 sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
171 buffer_append(&buf, encoded, enclen);
173 gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
174 gss_enc2oid[oidpos].encoded = encoded;
178 gss_enc2oid[oidpos].oid = NULL;
179 gss_enc2oid[oidpos].encoded = NULL;
181 buffer_put_char(&buf, '\0');
183 mechs = xmalloc(buffer_len(&buf));
184 buffer_get(&buf, mechs, buffer_len(&buf));
187 if (strlen(mechs) == 0) {
196 ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
200 case KEX_GSS_GRP1_SHA1:
201 if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
203 name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
205 case KEX_GSS_GRP14_SHA1:
206 if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
208 name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
210 case KEX_GSS_GEX_SHA1:
211 if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
213 name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
219 while (gss_enc2oid[i].encoded != NULL &&
220 strcmp(name, gss_enc2oid[i].encoded) != 0)
223 if (gss_enc2oid[i].oid != NULL && ctx != NULL)
224 ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
226 return gss_enc2oid[i].oid;
229 /* Check that the OID in a data stream matches that in the context */
231 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
233 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
234 ctx->oid->length == len &&
235 memcmp(ctx->oid->elements, data, len) == 0);
238 /* Set the contexts OID from a data stream */
240 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
242 if (ctx->oid != GSS_C_NO_OID) {
243 xfree(ctx->oid->elements);
246 ctx->oid = xmalloc(sizeof(gss_OID_desc));
247 ctx->oid->length = len;
248 ctx->oid->elements = xmalloc(len);
249 memcpy(ctx->oid->elements, data, len);
252 /* Set the contexts OID */
254 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
256 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
259 /* All this effort to report an error ... */
261 ssh_gssapi_error(Gssctxt *ctxt)
265 s = ssh_gssapi_last_error(ctxt, NULL, NULL);
271 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
272 OM_uint32 *minor_status)
275 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
282 if (major_status != NULL)
283 *major_status = ctxt->major;
284 if (minor_status != NULL)
285 *minor_status = ctxt->minor;
288 /* The GSSAPI error */
290 gss_display_status(&lmin, ctxt->major,
291 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
293 buffer_append(&b, msg.value, msg.length);
294 buffer_put_char(&b, '\n');
296 gss_release_buffer(&lmin, &msg);
299 /* The mechanism specific error */
301 gss_display_status(&lmin, ctxt->minor,
302 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
304 buffer_append(&b, msg.value, msg.length);
305 buffer_put_char(&b, '\n');
307 gss_release_buffer(&lmin, &msg);
310 buffer_put_char(&b, '\0');
311 ret = xmalloc(buffer_len(&b));
312 buffer_get(&b, ret, buffer_len(&b));
318 * Initialise our GSSAPI context. We use this opaque structure to contain all
319 * of the data which both the client and server need to persist across
320 * {accept,init}_sec_context calls, so that when we do it from the userauth
321 * stuff life is a little easier
324 ssh_gssapi_build_ctx(Gssctxt **ctx)
326 *ctx = xcalloc(1, sizeof (Gssctxt));
327 (*ctx)->context = GSS_C_NO_CONTEXT;
328 (*ctx)->name = GSS_C_NO_NAME;
329 (*ctx)->oid = GSS_C_NO_OID;
330 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
331 (*ctx)->client = GSS_C_NO_NAME;
332 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
335 /* Delete our context, providing it has been built correctly */
337 ssh_gssapi_delete_ctx(Gssctxt **ctx)
343 if ((*ctx)->context != GSS_C_NO_CONTEXT)
344 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
345 if ((*ctx)->name != GSS_C_NO_NAME)
346 gss_release_name(&ms, &(*ctx)->name);
347 if ((*ctx)->oid != GSS_C_NO_OID) {
348 xfree((*ctx)->oid->elements);
350 (*ctx)->oid = GSS_C_NO_OID;
352 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
353 gss_release_cred(&ms, &(*ctx)->creds);
354 if ((*ctx)->client != GSS_C_NO_NAME)
355 gss_release_name(&ms, &(*ctx)->client);
356 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
357 gss_release_cred(&ms, &(*ctx)->client_creds);
364 * Wrapper to init_sec_context
365 * Requires that the context contains:
367 * server name (from ssh_gssapi_import_name)
370 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
371 gss_buffer_desc* send_tok, OM_uint32 *flags)
376 deleg_flag = GSS_C_DELEG_FLAG;
377 debug("Delegating credentials");
380 ctx->major = gss_init_sec_context(&ctx->minor,
381 ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
382 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
383 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
385 if (GSS_ERROR(ctx->major))
386 ssh_gssapi_error(ctx);
391 /* Create a service name for the given host */
393 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
395 gss_buffer_desc gssbuf;
398 xasprintf(&val, "host@%s", host);
400 gssbuf.length = strlen(gssbuf.value);
402 if ((ctx->major = gss_import_name(&ctx->minor,
403 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
404 ssh_gssapi_error(ctx);
411 ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
413 gss_buffer_desc gssbuf;
418 gssbuf.value = (void *) name;
419 gssbuf.length = strlen(gssbuf.value);
421 gss_create_empty_oid_set(&status, &oidset);
422 gss_add_oid_set_member(&status, ctx->oid, &oidset);
424 ctx->major = gss_import_name(&ctx->minor, &gssbuf,
425 GSS_C_NT_USER_NAME, &gssname);
427 if (GSS_ERROR(ctx->major)) {
428 ssh_gssapi_error(ctx);
432 if (options.gss_password_prompt) {
436 snprintf(prompt, sizeof(prompt), "%.30s's password: ", name);
437 gss_password = read_passphrase(prompt, 0);
439 atexit(ssh_gssapi_cleanup_password);
442 gssbuf.value = gss_password;
443 gssbuf.length = strlen(gss_password);
445 ctx->major = gss_acquire_cred_with_password(&ctx->minor,
455 ctx->major = gss_acquire_cred(&ctx->minor,
465 gss_release_name(&status, &gssname);
466 gss_release_oid_set(&status, &oidset);
468 if (GSS_ERROR(ctx->major))
469 ssh_gssapi_error(ctx);
475 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
480 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
481 GSS_C_QOP_DEFAULT, buffer, hash)))
482 ssh_gssapi_error(ctx);
487 /* Priviledged when used by server */
489 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
494 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
495 gssbuf, gssmic, NULL);
501 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
505 buffer_put_string(b, session_id2, session_id2_len);
506 buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
507 buffer_put_cstring(b, user);
508 buffer_put_cstring(b, service);
509 buffer_put_cstring(b, context);
513 ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
516 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
517 OM_uint32 major, minor;
518 gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
519 Gssctxt *intctx = NULL;
525 * RFC 4462 says we MUST NOT do SPNEGO, but we relax that if
526 * the SPNEGO mechanism was explicitly specified by the user.
528 if (options.gss_mechanism_oid == GSS_C_NO_OID &&
529 oid->length == spnego_oid.length &&
530 (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
531 return 0; /* false */
533 ssh_gssapi_build_ctx(ctx);
534 ssh_gssapi_set_oid(*ctx, oid);
535 major = ssh_gssapi_import_name(*ctx, host);
537 if (!GSS_ERROR(major) && client)
538 major = ssh_gssapi_client_identity(*ctx, client);
540 if (!GSS_ERROR(major)) {
541 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
543 gss_release_buffer(&minor, &token);
544 if ((*ctx)->context != GSS_C_NO_CONTEXT)
545 gss_delete_sec_context(&minor, &(*ctx)->context,
549 if (GSS_ERROR(major) || intctx != NULL)
550 ssh_gssapi_delete_ctx(ctx);
552 return (!GSS_ERROR(major));
556 ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
557 static gss_name_t saved_name = GSS_C_NO_NAME;
558 static OM_uint32 saved_lifetime = 0;
559 static gss_OID saved_mech = GSS_C_NO_OID;
560 static gss_name_t name;
561 static OM_uint32 last_call = 0;
562 OM_uint32 lifetime, now, major, minor;
564 gss_cred_usage_t usage = GSS_C_INITIATE;
569 debug("Rekey has happened - updating saved versions");
571 if (saved_name != GSS_C_NO_NAME)
572 gss_release_name(&minor, &saved_name);
574 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
575 &saved_name, &saved_lifetime, NULL, NULL);
577 if (!GSS_ERROR(major)) {
578 saved_mech = ctxt->oid;
579 saved_lifetime+= now;
581 /* Handle the error */
586 if (now - last_call < 10)
591 if (saved_mech == GSS_C_NO_OID)
594 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
595 &name, &lifetime, NULL, NULL);
596 if (major == GSS_S_CREDENTIALS_EXPIRED)
598 else if (GSS_ERROR(major))
601 major = gss_compare_name(&minor, saved_name, name, &equal);
602 gss_release_name(&minor, &name);
603 if (GSS_ERROR(major))
606 if (equal && (saved_lifetime < lifetime + now - 10))