1 /* $OpenBSD: gss-serv.c,v 1.13 2005/10/13 22:24:31 stevesk 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.
34 #include <openssl/evp.h>
41 #include "monitor_wrap.h"
47 static ssh_gssapi_client gssapi_client =
48 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
49 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
51 ssh_gssapi_mech gssapi_null_mech =
52 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
55 extern ssh_gssapi_mech gssapi_kerberos_mech;
58 extern ssh_gssapi_mech gssapi_gsi_mech;
61 ssh_gssapi_mech* supported_mechs[]= {
63 &gssapi_kerberos_mech,
71 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
72 static int limited = 0;
77 ssh_gssapi_server_mechanisms() {
78 gss_OID_set supported;
80 ssh_gssapi_supported_oids(&supported);
81 return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
87 ssh_gssapi_server_check_mech(gss_OID oid, void *data) {
91 res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
92 ssh_gssapi_delete_ctx(&ctx);
99 ssh_gssapi_supported_oids(gss_OID_set *oidset)
102 OM_uint32 min_status;
104 gss_OID_set supported;
106 gss_create_empty_oid_set(&min_status, oidset);
107 /* Ask priviledged process what mechanisms it supports. */
108 PRIVSEP(gss_indicate_mechs(&min_status, &supported));
110 while (supported_mechs[i]->name != NULL) {
111 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
112 &supported_mechs[i]->oid, supported, &present)))
115 gss_add_oid_set_member(&min_status,
116 &supported_mechs[i]->oid, oidset);
122 /* Wrapper around accept_sec_context
123 * Requires that the context contains:
125 * credentials (from ssh_gssapi_acquire_cred)
129 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
130 gss_buffer_desc *send_tok, OM_uint32 *flags)
135 ctx->major = gss_accept_sec_context(&ctx->minor,
136 &ctx->context, ctx->creds, recv_tok,
137 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
138 send_tok, flags, NULL, &ctx->client_creds);
140 if (GSS_ERROR(ctx->major))
141 ssh_gssapi_error(ctx);
143 if (ctx->client_creds)
144 debug("Received some client credentials");
146 debug("Got no client credentials");
150 /* Now, if we're complete and we have the right flags, then
151 * we flag the user as also having been authenticated
154 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
155 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
156 if (ssh_gssapi_getclient(ctx, &gssapi_client))
157 fatal("Couldn't convert client name");
158 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
159 if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
168 * This parses an exported name, extracting the mechanism specific portion
169 * to use for ACL checking. It verifies that the name belongs the mechanism
170 * originally selected.
173 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
181 #ifdef GSI /* GSI gss_export_name() is broken. */
182 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
183 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
184 gssapi_gsi_mech.oid.length) == 0)) {
185 name->length = ename->length;
186 name->value = xmalloc(ename->length+1);
187 memcpy(name->value, ename->value, ename->length);
188 return GSS_S_COMPLETE;
193 * Check that ename is long enough for all of the fixed length
194 * header, and that the initial ID bytes are correct
197 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
198 return GSS_S_FAILURE;
201 * Extract the OID, and check it. Here GSSAPI breaks with tradition
202 * and does use the OID type and length bytes. To confuse things
203 * there are two lengths - the first including these, and the
207 oidl = GET_16BIT(tok+2); /* length including next two bytes */
208 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
211 * Check the BER encoding for correct type and length, that the
212 * string is long enough and that the OID matches that in our context
214 if (tok[4] != 0x06 || tok[5] != oidl ||
215 ename->length < oidl+6 ||
216 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
217 return GSS_S_FAILURE;
221 if (ename->length < offset+4)
222 return GSS_S_FAILURE;
224 name->length = GET_32BIT(tok+offset);
227 if (ename->length < offset+name->length)
228 return GSS_S_FAILURE;
230 name->value = xmalloc(name->length+1);
231 memcpy(name->value, tok+offset,name->length);
232 ((char *)name->value)[name->length] = 0;
234 return GSS_S_COMPLETE;
237 /* Extract the client details from a given context. This can only reliably
238 * be called once for a context */
240 /* Privileged (called from accept_secure_ctx) */
242 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
246 gss_buffer_desc ename;
250 while (supported_mechs[i]->name != NULL) {
251 if (supported_mechs[i]->oid.length == ctx->oid->length &&
252 (memcmp(supported_mechs[i]->oid.elements,
253 ctx->oid->elements, ctx->oid->length) == 0))
254 client->mech = supported_mechs[i];
258 if (client->mech == NULL)
259 return GSS_S_FAILURE;
261 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
262 &client->displayname, NULL))) {
263 ssh_gssapi_error(ctx);
267 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
269 ssh_gssapi_error(ctx);
273 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
274 &client->exportedname))) {
278 /* We can't copy this structure, so we just move the pointer to it */
279 client->creds = ctx->client_creds;
280 ctx->client_creds = GSS_C_NO_CREDENTIAL;
284 /* As user - called on fatal/exit */
286 ssh_gssapi_cleanup_creds(void)
288 if (gssapi_client.store.filename != NULL) {
289 /* Unlink probably isn't sufficient */
290 debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
291 unlink(gssapi_client.store.filename);
297 ssh_gssapi_storecreds(void)
299 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
300 (*gssapi_client.mech->storecreds)(&gssapi_client);
302 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
305 /* This allows GSSAPI methods to do things to the childs environment based
306 * on the passed authentication process and credentials.
310 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
313 if (gssapi_client.store.envvar != NULL &&
314 gssapi_client.store.envval != NULL) {
315 debug("Setting %s to %s", gssapi_client.store.envvar,
316 gssapi_client.store.envval);
317 child_set_env(envp, envsizep, gssapi_client.store.envvar,
318 gssapi_client.store.envval);
324 ssh_gssapi_userok(char *user)
328 if (gssapi_client.exportedname.length == 0 ||
329 gssapi_client.exportedname.value == NULL) {
330 debug("No suitable client data");
333 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
335 debug("limited proxy not acceptable for remote login");
339 if (gssapi_client.mech && gssapi_client.mech->userok)
340 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
343 /* Destroy delegated credentials if userok fails */
344 gss_release_buffer(&lmin, &gssapi_client.displayname);
345 gss_release_buffer(&lmin, &gssapi_client.exportedname);
346 gss_release_cred(&lmin, &gssapi_client.creds);
347 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
351 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
357 ssh_gssapi_localname(char **user)
360 if (gssapi_client.displayname.length==0 ||
361 gssapi_client.displayname.value==NULL) {
362 debug("No suitable client data");
365 if (gssapi_client.mech && gssapi_client.mech->localname) {
366 return((*gssapi_client.mech->localname)(&gssapi_client,user));
368 debug("Unknown client authentication type");