1 /* $OpenBSD: gss-serv.c,v 1.22 2008/05/08 12:02:23 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>
38 #include "openbsd-compat/sys-queue.h"
52 #include "monitor_wrap.h"
54 extern ServerOptions options;
55 extern Authctxt *the_authctxt;
57 static ssh_gssapi_client gssapi_client =
58 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
59 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
61 ssh_gssapi_mech gssapi_null_mech =
62 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
65 extern ssh_gssapi_mech gssapi_kerberos_mech;
68 extern ssh_gssapi_mech gssapi_gsi_mech;
71 ssh_gssapi_mech* supported_mechs[]= {
73 &gssapi_kerberos_mech,
81 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
82 static int limited = 0;
87 ssh_gssapi_server_mechanisms() {
88 gss_OID_set supported;
90 ssh_gssapi_supported_oids(&supported);
91 return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
97 ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data) {
101 res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
102 ssh_gssapi_delete_ctx(&ctx);
108 * Acquire credentials for a server running on the current host.
109 * Requires that the context structure contains a valid OID
112 /* Returns a GSSAPI error code */
113 /* Privileged (called from ssh_gssapi_server_ctx) */
115 ssh_gssapi_acquire_cred(Gssctxt *ctx)
118 char lname[MAXHOSTNAMELEN];
121 if (options.gss_strict_acceptor) {
122 gss_create_empty_oid_set(&status, &oidset);
123 gss_add_oid_set_member(&status, ctx->oid, &oidset);
125 if (gethostname(lname, MAXHOSTNAMELEN)) {
126 gss_release_oid_set(&status, &oidset);
130 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
131 gss_release_oid_set(&status, &oidset);
135 if ((ctx->major = gss_acquire_cred(&ctx->minor,
136 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds,
138 ssh_gssapi_error(ctx);
140 gss_release_oid_set(&status, &oidset);
143 ctx->name = GSS_C_NO_NAME;
144 ctx->creds = GSS_C_NO_CREDENTIAL;
146 return GSS_S_COMPLETE;
152 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
155 ssh_gssapi_delete_ctx(ctx);
156 ssh_gssapi_build_ctx(ctx);
157 ssh_gssapi_set_oid(*ctx, oid);
158 return (ssh_gssapi_acquire_cred(*ctx));
163 ssh_gssapi_supported_oids(gss_OID_set *oidset)
166 OM_uint32 min_status;
168 gss_OID_set supported;
170 gss_create_empty_oid_set(&min_status, oidset);
171 /* Ask priviledged process what mechanisms it supports. */
172 PRIVSEP(gss_indicate_mechs(&min_status, &supported));
174 while (supported_mechs[i]->name != NULL) {
175 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
176 &supported_mechs[i]->oid, supported, &present)))
179 gss_add_oid_set_member(&min_status,
180 &supported_mechs[i]->oid, oidset);
184 gss_release_oid_set(&min_status, &supported);
188 /* Wrapper around accept_sec_context
189 * Requires that the context contains:
191 * credentials (from ssh_gssapi_acquire_cred)
195 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
196 gss_buffer_desc *send_tok, OM_uint32 *flags)
201 ctx->major = gss_accept_sec_context(&ctx->minor,
202 &ctx->context, ctx->creds, recv_tok,
203 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
204 send_tok, flags, NULL, &ctx->client_creds);
206 if (GSS_ERROR(ctx->major))
207 ssh_gssapi_error(ctx);
209 if (ctx->client_creds)
210 debug("Received some client credentials");
212 debug("Got no client credentials");
216 /* Now, if we're complete and we have the right flags, then
217 * we flag the user as also having been authenticated
220 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
221 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
222 if (ssh_gssapi_getclient(ctx, &gssapi_client))
223 fatal("Couldn't convert client name");
224 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
225 if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
234 * This parses an exported name, extracting the mechanism specific portion
235 * to use for ACL checking. It verifies that the name belongs the mechanism
236 * originally selected.
239 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
247 #ifdef GSI /* GSI gss_export_name() is broken. */
248 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
249 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
250 gssapi_gsi_mech.oid.length) == 0)) {
251 name->length = ename->length;
252 name->value = xmalloc(ename->length+1);
253 memcpy(name->value, ename->value, ename->length);
254 return GSS_S_COMPLETE;
259 * Check that ename is long enough for all of the fixed length
260 * header, and that the initial ID bytes are correct
263 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
264 return GSS_S_FAILURE;
267 * Extract the OID, and check it. Here GSSAPI breaks with tradition
268 * and does use the OID type and length bytes. To confuse things
269 * there are two lengths - the first including these, and the
273 oidl = get_u16(tok+2); /* length including next two bytes */
274 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
277 * Check the BER encoding for correct type and length, that the
278 * string is long enough and that the OID matches that in our context
280 if (tok[4] != 0x06 || tok[5] != oidl ||
281 ename->length < oidl+6 ||
282 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
283 return GSS_S_FAILURE;
287 if (ename->length < offset+4)
288 return GSS_S_FAILURE;
290 name->length = get_u32(tok+offset);
293 if (ename->length < offset+name->length)
294 return GSS_S_FAILURE;
296 name->value = xmalloc(name->length+1);
297 memcpy(name->value, tok+offset, name->length);
298 ((char *)name->value)[name->length] = 0;
300 return GSS_S_COMPLETE;
303 /* Extract the client details from a given context. This can only reliably
304 * be called once for a context */
306 /* Privileged (called from accept_secure_ctx) */
308 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
312 gss_buffer_desc ename;
316 while (supported_mechs[i]->name != NULL) {
317 if (supported_mechs[i]->oid.length == ctx->oid->length &&
318 (memcmp(supported_mechs[i]->oid.elements,
319 ctx->oid->elements, ctx->oid->length) == 0))
320 client->mech = supported_mechs[i];
324 if (client->mech == NULL)
325 return GSS_S_FAILURE;
327 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
328 &client->displayname, NULL))) {
329 ssh_gssapi_error(ctx);
333 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
335 ssh_gssapi_error(ctx);
339 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
340 &client->exportedname))) {
344 /* We can't copy this structure, so we just move the pointer to it */
345 client->creds = ctx->client_creds;
346 ctx->client_creds = GSS_C_NO_CREDENTIAL;
348 /* needed for globus_gss_assist_map_and_authorize() */
349 client->context = ctx->context;
354 /* As user - called on fatal/exit */
356 ssh_gssapi_cleanup_creds(void)
358 if (gssapi_client.store.filename != NULL) {
359 /* Unlink probably isn't sufficient */
360 debug("removing gssapi cred file\"%s\"",
361 gssapi_client.store.filename);
362 unlink(gssapi_client.store.filename);
368 ssh_gssapi_storecreds(void)
370 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
371 if (options.gss_creds_path) {
372 gssapi_client.store.filename =
373 expand_authorized_keys(options.gss_creds_path,
376 (*gssapi_client.mech->storecreds)(&gssapi_client);
378 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
381 /* This allows GSSAPI methods to do things to the childs environment based
382 * on the passed authentication process and credentials.
386 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
389 if (gssapi_client.store.envvar != NULL &&
390 gssapi_client.store.envval != NULL) {
391 debug("Setting %s to %s", gssapi_client.store.envvar,
392 gssapi_client.store.envval);
393 child_set_env(envp, envsizep, gssapi_client.store.envvar,
394 gssapi_client.store.envval);
400 ssh_gssapi_userok(char *user)
404 if (gssapi_client.exportedname.length == 0 ||
405 gssapi_client.exportedname.value == NULL) {
406 debug("No suitable client data");
409 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
410 if (limited && options.gsi_allow_limited_proxy != 1) {
411 debug("limited proxy not acceptable for remote login");
415 if (gssapi_client.mech && gssapi_client.mech->userok)
416 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
419 /* Destroy delegated credentials if userok fails */
420 gss_release_buffer(&lmin, &gssapi_client.displayname);
421 gss_release_buffer(&lmin, &gssapi_client.exportedname);
422 gss_release_cred(&lmin, &gssapi_client.creds);
423 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
427 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
431 /* ssh_gssapi_checkmic() moved to gss-genr.c so it can be called by
436 ssh_gssapi_localname(char **user)
439 if (gssapi_client.displayname.length==0 ||
440 gssapi_client.displayname.value==NULL) {
441 debug("No suitable client data");
444 if (gssapi_client.mech && gssapi_client.mech->localname) {
445 return((*gssapi_client.mech->localname)(&gssapi_client,user));
447 debug("Unknown client authentication type");