1 /* $OpenBSD: gss-serv.c,v 1.20 2006/08/03 03:34:42 deraadt 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>
50 #include "monitor_wrap.h"
52 extern ServerOptions options;
53 extern Authctxt *the_authctxt;
55 static ssh_gssapi_client gssapi_client =
56 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
57 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
59 ssh_gssapi_mech gssapi_null_mech =
60 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
63 extern ssh_gssapi_mech gssapi_kerberos_mech;
66 extern ssh_gssapi_mech gssapi_gsi_mech;
69 ssh_gssapi_mech* supported_mechs[]= {
71 &gssapi_kerberos_mech,
79 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
80 static int limited = 0;
85 ssh_gssapi_server_mechanisms() {
86 gss_OID_set supported;
88 ssh_gssapi_supported_oids(&supported);
89 return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
95 ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data) {
99 res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
100 ssh_gssapi_delete_ctx(&ctx);
107 ssh_gssapi_supported_oids(gss_OID_set *oidset)
110 OM_uint32 min_status;
112 gss_OID_set supported;
114 gss_create_empty_oid_set(&min_status, oidset);
115 /* Ask priviledged process what mechanisms it supports. */
116 PRIVSEP(gss_indicate_mechs(&min_status, &supported));
118 while (supported_mechs[i]->name != NULL) {
119 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
120 &supported_mechs[i]->oid, supported, &present)))
123 gss_add_oid_set_member(&min_status,
124 &supported_mechs[i]->oid, oidset);
128 gss_release_oid_set(&min_status, &supported);
132 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
135 ssh_gssapi_delete_ctx(ctx);
136 ssh_gssapi_build_ctx(ctx);
137 ssh_gssapi_set_oid(*ctx, oid);
138 return (ssh_gssapi_acquire_cred(*ctx));
141 /* Acquire credentials for a server running on the current host.
142 * Requires that the context structure contains a valid OID
145 /* Returns a GSSAPI error code */
147 ssh_gssapi_acquire_cred(Gssctxt *ctx)
150 char lname[MAXHOSTNAMELEN];
153 if (options.gss_strict_acceptor) {
154 gss_create_empty_oid_set(&status, &oidset);
155 gss_add_oid_set_member(&status, ctx->oid, &oidset);
157 if (gethostname(lname, MAXHOSTNAMELEN)) {
158 gss_release_oid_set(&status, &oidset);
162 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
163 gss_release_oid_set(&status, &oidset);
167 if ((ctx->major = gss_acquire_cred(&ctx->minor,
168 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds,
170 ssh_gssapi_error(ctx);
172 gss_release_oid_set(&status, &oidset);
175 ctx->name = GSS_C_NO_NAME;
176 ctx->creds = GSS_C_NO_CREDENTIAL;
178 return GSS_S_COMPLETE;
182 /* Wrapper around accept_sec_context
183 * Requires that the context contains:
185 * credentials (from ssh_gssapi_acquire_cred)
189 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
190 gss_buffer_desc *send_tok, OM_uint32 *flags)
195 ctx->major = gss_accept_sec_context(&ctx->minor,
196 &ctx->context, ctx->creds, recv_tok,
197 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
198 send_tok, flags, NULL, &ctx->client_creds);
200 if (GSS_ERROR(ctx->major))
201 ssh_gssapi_error(ctx);
203 if (ctx->client_creds)
204 debug("Received some client credentials");
206 debug("Got no client credentials");
210 /* Now, if we're complete and we have the right flags, then
211 * we flag the user as also having been authenticated
214 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
215 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
216 if (ssh_gssapi_getclient(ctx, &gssapi_client))
217 fatal("Couldn't convert client name");
218 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
219 if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
228 * This parses an exported name, extracting the mechanism specific portion
229 * to use for ACL checking. It verifies that the name belongs the mechanism
230 * originally selected.
233 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
241 #ifdef GSI /* GSI gss_export_name() is broken. */
242 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
243 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
244 gssapi_gsi_mech.oid.length) == 0)) {
245 name->length = ename->length;
246 name->value = xmalloc(ename->length+1);
247 memcpy(name->value, ename->value, ename->length);
248 return GSS_S_COMPLETE;
253 * Check that ename is long enough for all of the fixed length
254 * header, and that the initial ID bytes are correct
257 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
258 return GSS_S_FAILURE;
261 * Extract the OID, and check it. Here GSSAPI breaks with tradition
262 * and does use the OID type and length bytes. To confuse things
263 * there are two lengths - the first including these, and the
267 oidl = get_u16(tok+2); /* length including next two bytes */
268 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
271 * Check the BER encoding for correct type and length, that the
272 * string is long enough and that the OID matches that in our context
274 if (tok[4] != 0x06 || tok[5] != oidl ||
275 ename->length < oidl+6 ||
276 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
277 return GSS_S_FAILURE;
281 if (ename->length < offset+4)
282 return GSS_S_FAILURE;
284 name->length = get_u32(tok+offset);
287 if (ename->length < offset+name->length)
288 return GSS_S_FAILURE;
290 name->value = xmalloc(name->length+1);
291 memcpy(name->value, tok+offset, name->length);
292 ((char *)name->value)[name->length] = 0;
294 return GSS_S_COMPLETE;
297 /* Extract the client details from a given context. This can only reliably
298 * be called once for a context */
300 /* Privileged (called from accept_secure_ctx) */
302 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
306 gss_buffer_desc ename;
310 while (supported_mechs[i]->name != NULL) {
311 if (supported_mechs[i]->oid.length == ctx->oid->length &&
312 (memcmp(supported_mechs[i]->oid.elements,
313 ctx->oid->elements, ctx->oid->length) == 0))
314 client->mech = supported_mechs[i];
318 if (client->mech == NULL)
319 return GSS_S_FAILURE;
321 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
322 &client->displayname, NULL))) {
323 ssh_gssapi_error(ctx);
327 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
329 ssh_gssapi_error(ctx);
333 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
334 &client->exportedname))) {
338 /* We can't copy this structure, so we just move the pointer to it */
339 client->creds = ctx->client_creds;
340 ctx->client_creds = GSS_C_NO_CREDENTIAL;
342 /* needed for globus_gss_assist_map_and_authorize() */
343 client->context = ctx->context;
348 /* As user - called on fatal/exit */
350 ssh_gssapi_cleanup_creds(void)
352 if (gssapi_client.store.filename != NULL) {
353 /* Unlink probably isn't sufficient */
354 debug("removing gssapi cred file\"%s\"",
355 gssapi_client.store.filename);
356 unlink(gssapi_client.store.filename);
362 ssh_gssapi_storecreds(void)
364 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
365 if (options.gss_creds_path) {
366 gssapi_client.store.filename =
367 expand_authorized_keys(options.gss_creds_path,
370 (*gssapi_client.mech->storecreds)(&gssapi_client);
372 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
375 /* This allows GSSAPI methods to do things to the childs environment based
376 * on the passed authentication process and credentials.
380 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
383 if (gssapi_client.store.envvar != NULL &&
384 gssapi_client.store.envval != NULL) {
385 debug("Setting %s to %s", gssapi_client.store.envvar,
386 gssapi_client.store.envval);
387 child_set_env(envp, envsizep, gssapi_client.store.envvar,
388 gssapi_client.store.envval);
394 ssh_gssapi_userok(char *user)
398 if (gssapi_client.exportedname.length == 0 ||
399 gssapi_client.exportedname.value == NULL) {
400 debug("No suitable client data");
403 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
404 if (limited && options.gsi_allow_limited_proxy != 1) {
405 debug("limited proxy not acceptable for remote login");
409 if (gssapi_client.mech && gssapi_client.mech->userok)
410 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
413 /* Destroy delegated credentials if userok fails */
414 gss_release_buffer(&lmin, &gssapi_client.displayname);
415 gss_release_buffer(&lmin, &gssapi_client.exportedname);
416 gss_release_cred(&lmin, &gssapi_client.creds);
417 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
421 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
427 ssh_gssapi_localname(char **user)
430 if (gssapi_client.displayname.length==0 ||
431 gssapi_client.displayname.value==NULL) {
432 debug("No suitable client data");
435 if (gssapi_client.mech && gssapi_client.mech->localname) {
436 return((*gssapi_client.mech->localname)(&gssapi_client,user));
438 debug("Unknown client authentication type");