1 /* $OpenBSD: gss-serv.c,v 1.21 2007/06/12 08:20:00 djm Exp $ */
4 * Copyright (c) 2001-2006 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>
51 #include "monitor_wrap.h"
53 extern ServerOptions options;
54 extern Authctxt *the_authctxt;
56 static ssh_gssapi_client gssapi_client =
57 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
58 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
60 ssh_gssapi_mech gssapi_null_mech =
61 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
64 extern ssh_gssapi_mech gssapi_kerberos_mech;
67 extern ssh_gssapi_mech gssapi_gsi_mech;
70 ssh_gssapi_mech* supported_mechs[]= {
72 &gssapi_kerberos_mech,
80 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
81 static int limited = 0;
86 ssh_gssapi_server_mechanisms() {
87 gss_OID_set supported;
89 ssh_gssapi_supported_oids(&supported);
90 return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
96 ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data) {
100 res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
101 ssh_gssapi_delete_ctx(&ctx);
107 * Acquire credentials for a server running on the current host.
108 * Requires that the context structure contains a valid OID
111 /* Returns a GSSAPI error code */
112 /* Privileged (called from ssh_gssapi_server_ctx) */
114 ssh_gssapi_acquire_cred(Gssctxt *ctx)
117 char lname[MAXHOSTNAMELEN];
120 if (options.gss_strict_acceptor) {
121 gss_create_empty_oid_set(&status, &oidset);
122 gss_add_oid_set_member(&status, ctx->oid, &oidset);
124 if (gethostname(lname, MAXHOSTNAMELEN)) {
125 gss_release_oid_set(&status, &oidset);
129 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
130 gss_release_oid_set(&status, &oidset);
134 if ((ctx->major = gss_acquire_cred(&ctx->minor,
135 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds,
137 ssh_gssapi_error(ctx);
139 gss_release_oid_set(&status, &oidset);
142 ctx->name = GSS_C_NO_NAME;
143 ctx->creds = GSS_C_NO_CREDENTIAL;
145 return GSS_S_COMPLETE;
151 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
154 ssh_gssapi_delete_ctx(ctx);
155 ssh_gssapi_build_ctx(ctx);
156 ssh_gssapi_set_oid(*ctx, oid);
157 return (ssh_gssapi_acquire_cred(*ctx));
162 ssh_gssapi_supported_oids(gss_OID_set *oidset)
165 OM_uint32 min_status;
167 gss_OID_set supported;
169 gss_create_empty_oid_set(&min_status, oidset);
170 /* Ask priviledged process what mechanisms it supports. */
171 PRIVSEP(gss_indicate_mechs(&min_status, &supported));
173 while (supported_mechs[i]->name != NULL) {
174 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
175 &supported_mechs[i]->oid, supported, &present)))
178 gss_add_oid_set_member(&min_status,
179 &supported_mechs[i]->oid, oidset);
183 gss_release_oid_set(&min_status, &supported);
187 /* Wrapper around accept_sec_context
188 * Requires that the context contains:
190 * credentials (from ssh_gssapi_acquire_cred)
194 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
195 gss_buffer_desc *send_tok, OM_uint32 *flags)
200 ctx->major = gss_accept_sec_context(&ctx->minor,
201 &ctx->context, ctx->creds, recv_tok,
202 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
203 send_tok, flags, NULL, &ctx->client_creds);
205 if (GSS_ERROR(ctx->major))
206 ssh_gssapi_error(ctx);
208 if (ctx->client_creds)
209 debug("Received some client credentials");
211 debug("Got no client credentials");
215 /* Now, if we're complete and we have the right flags, then
216 * we flag the user as also having been authenticated
219 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
220 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
221 if (ssh_gssapi_getclient(ctx, &gssapi_client))
222 fatal("Couldn't convert client name");
223 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
224 if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
233 * This parses an exported name, extracting the mechanism specific portion
234 * to use for ACL checking. It verifies that the name belongs the mechanism
235 * originally selected.
238 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
246 #ifdef GSI /* GSI gss_export_name() is broken. */
247 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
248 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
249 gssapi_gsi_mech.oid.length) == 0)) {
250 name->length = ename->length;
251 name->value = xmalloc(ename->length+1);
252 memcpy(name->value, ename->value, ename->length);
253 return GSS_S_COMPLETE;
258 * Check that ename is long enough for all of the fixed length
259 * header, and that the initial ID bytes are correct
262 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
263 return GSS_S_FAILURE;
266 * Extract the OID, and check it. Here GSSAPI breaks with tradition
267 * and does use the OID type and length bytes. To confuse things
268 * there are two lengths - the first including these, and the
272 oidl = get_u16(tok+2); /* length including next two bytes */
273 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
276 * Check the BER encoding for correct type and length, that the
277 * string is long enough and that the OID matches that in our context
279 if (tok[4] != 0x06 || tok[5] != oidl ||
280 ename->length < oidl+6 ||
281 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
282 return GSS_S_FAILURE;
286 if (ename->length < offset+4)
287 return GSS_S_FAILURE;
289 name->length = get_u32(tok+offset);
292 if (ename->length < offset+name->length)
293 return GSS_S_FAILURE;
295 name->value = xmalloc(name->length+1);
296 memcpy(name->value, tok+offset, name->length);
297 ((char *)name->value)[name->length] = 0;
299 return GSS_S_COMPLETE;
302 /* Extract the client details from a given context. This can only reliably
303 * be called once for a context */
305 /* Privileged (called from accept_secure_ctx) */
307 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
311 gss_buffer_desc ename;
315 while (supported_mechs[i]->name != NULL) {
316 if (supported_mechs[i]->oid.length == ctx->oid->length &&
317 (memcmp(supported_mechs[i]->oid.elements,
318 ctx->oid->elements, ctx->oid->length) == 0))
319 client->mech = supported_mechs[i];
323 if (client->mech == NULL)
324 return GSS_S_FAILURE;
326 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
327 &client->displayname, NULL))) {
328 ssh_gssapi_error(ctx);
332 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
334 ssh_gssapi_error(ctx);
338 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
339 &client->exportedname))) {
343 /* We can't copy this structure, so we just move the pointer to it */
344 client->creds = ctx->client_creds;
345 ctx->client_creds = GSS_C_NO_CREDENTIAL;
347 /* needed for globus_gss_assist_map_and_authorize() */
348 client->context = ctx->context;
353 /* As user - called on fatal/exit */
355 ssh_gssapi_cleanup_creds(void)
357 if (gssapi_client.store.filename != NULL) {
358 /* Unlink probably isn't sufficient */
359 debug("removing gssapi cred file\"%s\"",
360 gssapi_client.store.filename);
361 unlink(gssapi_client.store.filename);
367 ssh_gssapi_storecreds(void)
369 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
370 if (options.gss_creds_path) {
371 gssapi_client.store.filename =
372 expand_authorized_keys(options.gss_creds_path,
375 (*gssapi_client.mech->storecreds)(&gssapi_client);
377 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
380 /* This allows GSSAPI methods to do things to the childs environment based
381 * on the passed authentication process and credentials.
385 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
388 if (gssapi_client.store.envvar != NULL &&
389 gssapi_client.store.envval != NULL) {
390 debug("Setting %s to %s", gssapi_client.store.envvar,
391 gssapi_client.store.envval);
392 child_set_env(envp, envsizep, gssapi_client.store.envvar,
393 gssapi_client.store.envval);
399 ssh_gssapi_userok(char *user)
403 if (gssapi_client.exportedname.length == 0 ||
404 gssapi_client.exportedname.value == NULL) {
405 debug("No suitable client data");
408 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
409 if (limited && options.gsi_allow_limited_proxy != 1) {
410 debug("limited proxy not acceptable for remote login");
414 if (gssapi_client.mech && gssapi_client.mech->userok)
415 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
418 /* Destroy delegated credentials if userok fails */
419 gss_release_buffer(&lmin, &gssapi_client.displayname);
420 gss_release_buffer(&lmin, &gssapi_client.exportedname);
421 gss_release_cred(&lmin, &gssapi_client.creds);
422 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
426 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
430 /* ssh_gssapi_checkmic() moved to gss-genr.c so it can be called by
435 ssh_gssapi_localname(char **user)
438 if (gssapi_client.displayname.length==0 ||
439 gssapi_client.displayname.value==NULL) {
440 debug("No suitable client data");
443 if (gssapi_client.mech && gssapi_client.mech->localname) {
444 return((*gssapi_client.mech->localname)(&gssapi_client,user));
446 debug("Unknown client authentication type");