1 /* $OpenBSD: gss-serv.c,v 1.21 2007/06/12 08:20:00 djm Exp $ */
4 * Copyright (c) 2001-2003 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>
50 static ssh_gssapi_client gssapi_client =
51 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
52 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
54 ssh_gssapi_mech gssapi_null_mech =
55 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
58 extern ssh_gssapi_mech gssapi_kerberos_mech;
61 ssh_gssapi_mech* supported_mechs[]= {
63 &gssapi_kerberos_mech,
70 * Acquire credentials for a server running on the current host.
71 * Requires that the context structure contains a valid OID
74 /* Returns a GSSAPI error code */
75 /* Privileged (called from ssh_gssapi_server_ctx) */
77 ssh_gssapi_acquire_cred(Gssctxt *ctx)
80 char lname[MAXHOSTNAMELEN];
83 gss_create_empty_oid_set(&status, &oidset);
84 gss_add_oid_set_member(&status, ctx->oid, &oidset);
86 if (gethostname(lname, MAXHOSTNAMELEN)) {
87 gss_release_oid_set(&status, &oidset);
91 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
92 gss_release_oid_set(&status, &oidset);
96 if ((ctx->major = gss_acquire_cred(&ctx->minor,
97 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
98 ssh_gssapi_error(ctx);
100 gss_release_oid_set(&status, &oidset);
106 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
109 ssh_gssapi_delete_ctx(ctx);
110 ssh_gssapi_build_ctx(ctx);
111 ssh_gssapi_set_oid(*ctx, oid);
112 return (ssh_gssapi_acquire_cred(*ctx));
117 ssh_gssapi_supported_oids(gss_OID_set *oidset)
120 OM_uint32 min_status;
122 gss_OID_set supported;
124 gss_create_empty_oid_set(&min_status, oidset);
125 gss_indicate_mechs(&min_status, &supported);
127 while (supported_mechs[i]->name != NULL) {
128 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
129 &supported_mechs[i]->oid, supported, &present)))
132 gss_add_oid_set_member(&min_status,
133 &supported_mechs[i]->oid, oidset);
137 gss_release_oid_set(&min_status, &supported);
141 /* Wrapper around accept_sec_context
142 * Requires that the context contains:
144 * credentials (from ssh_gssapi_acquire_cred)
148 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
149 gss_buffer_desc *send_tok, OM_uint32 *flags)
154 ctx->major = gss_accept_sec_context(&ctx->minor,
155 &ctx->context, ctx->creds, recv_tok,
156 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
157 send_tok, flags, NULL, &ctx->client_creds);
159 if (GSS_ERROR(ctx->major))
160 ssh_gssapi_error(ctx);
162 if (ctx->client_creds)
163 debug("Received some client credentials");
165 debug("Got no client credentials");
169 /* Now, if we're complete and we have the right flags, then
170 * we flag the user as also having been authenticated
173 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
174 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
175 if (ssh_gssapi_getclient(ctx, &gssapi_client))
176 fatal("Couldn't convert client name");
183 * This parses an exported name, extracting the mechanism specific portion
184 * to use for ACL checking. It verifies that the name belongs the mechanism
185 * originally selected.
188 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
197 * Check that ename is long enough for all of the fixed length
198 * header, and that the initial ID bytes are correct
201 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
202 return GSS_S_FAILURE;
205 * Extract the OID, and check it. Here GSSAPI breaks with tradition
206 * and does use the OID type and length bytes. To confuse things
207 * there are two lengths - the first including these, and the
211 oidl = get_u16(tok+2); /* length including next two bytes */
212 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
215 * Check the BER encoding for correct type and length, that the
216 * string is long enough and that the OID matches that in our context
218 if (tok[4] != 0x06 || tok[5] != oidl ||
219 ename->length < oidl+6 ||
220 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
221 return GSS_S_FAILURE;
225 if (ename->length < offset+4)
226 return GSS_S_FAILURE;
228 name->length = get_u32(tok+offset);
231 if (ename->length < offset+name->length)
232 return GSS_S_FAILURE;
234 name->value = xmalloc(name->length+1);
235 memcpy(name->value, tok+offset, name->length);
236 ((char *)name->value)[name->length] = 0;
238 return GSS_S_COMPLETE;
241 /* Extract the client details from a given context. This can only reliably
242 * be called once for a context */
244 /* Privileged (called from accept_secure_ctx) */
246 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
250 gss_buffer_desc ename;
254 while (supported_mechs[i]->name != NULL) {
255 if (supported_mechs[i]->oid.length == ctx->oid->length &&
256 (memcmp(supported_mechs[i]->oid.elements,
257 ctx->oid->elements, ctx->oid->length) == 0))
258 client->mech = supported_mechs[i];
262 if (client->mech == NULL)
263 return GSS_S_FAILURE;
265 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
266 &client->displayname, NULL))) {
267 ssh_gssapi_error(ctx);
271 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
273 ssh_gssapi_error(ctx);
277 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
278 &client->exportedname))) {
282 /* We can't copy this structure, so we just move the pointer to it */
283 client->creds = ctx->client_creds;
284 ctx->client_creds = GSS_C_NO_CREDENTIAL;
288 /* As user - called on fatal/exit */
290 ssh_gssapi_cleanup_creds(void)
292 if (gssapi_client.store.filename != NULL) {
293 /* Unlink probably isn't sufficient */
294 debug("removing gssapi cred file\"%s\"",
295 gssapi_client.store.filename);
296 unlink(gssapi_client.store.filename);
302 ssh_gssapi_storecreds(void)
304 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
305 (*gssapi_client.mech->storecreds)(&gssapi_client);
307 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
310 /* This allows GSSAPI methods to do things to the childs environment based
311 * on the passed authentication process and credentials.
315 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
318 if (gssapi_client.store.envvar != NULL &&
319 gssapi_client.store.envval != NULL) {
320 debug("Setting %s to %s", gssapi_client.store.envvar,
321 gssapi_client.store.envval);
322 child_set_env(envp, envsizep, gssapi_client.store.envvar,
323 gssapi_client.store.envval);
329 ssh_gssapi_userok(char *user)
333 if (gssapi_client.exportedname.length == 0 ||
334 gssapi_client.exportedname.value == NULL) {
335 debug("No suitable client data");
338 if (gssapi_client.mech && gssapi_client.mech->userok)
339 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
342 /* Destroy delegated credentials if userok fails */
343 gss_release_buffer(&lmin, &gssapi_client.displayname);
344 gss_release_buffer(&lmin, &gssapi_client.exportedname);
345 gss_release_cred(&lmin, &gssapi_client.creds);
346 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
350 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
356 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
358 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
359 gssbuf, gssmic, NULL);