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.
39 #include "monitor_wrap.h"
43 static ssh_gssapi_client gssapi_client =
44 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
45 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
47 ssh_gssapi_mech gssapi_null_mech =
48 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
51 extern ssh_gssapi_mech gssapi_kerberos_mech;
54 extern ssh_gssapi_mech gssapi_gsi_mech;
57 ssh_gssapi_mech* supported_mechs[]= {
59 &gssapi_kerberos_mech,
67 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
68 static int limited = 0;
73 ssh_gssapi_server_mechanisms() {
74 gss_OID_set supported;
76 ssh_gssapi_supported_oids(&supported);
77 return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech,
83 ssh_gssapi_server_check_mech(gss_OID oid, void *data) {
87 res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
88 ssh_gssapi_delete_ctx(&ctx);
95 ssh_gssapi_supported_oids(gss_OID_set *oidset)
100 gss_OID_set supported;
102 gss_create_empty_oid_set(&min_status, oidset);
103 /* Ask priviledged process what mechanisms it supports. */
104 PRIVSEP(gss_indicate_mechs(&min_status, &supported));
106 while (supported_mechs[i]->name != NULL) {
107 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
108 &supported_mechs[i]->oid, supported, &present)))
111 gss_add_oid_set_member(&min_status,
112 &supported_mechs[i]->oid, oidset);
118 /* Wrapper around accept_sec_context
119 * Requires that the context contains:
121 * credentials (from ssh_gssapi_acquire_cred)
125 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
126 gss_buffer_desc *send_tok, OM_uint32 *flags)
131 ctx->major = gss_accept_sec_context(&ctx->minor,
132 &ctx->context, ctx->creds, recv_tok,
133 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
134 send_tok, flags, NULL, &ctx->client_creds);
136 if (GSS_ERROR(ctx->major))
137 ssh_gssapi_error(ctx);
139 if (ctx->client_creds)
140 debug("Received some client credentials");
142 debug("Got no client credentials");
146 /* Now, if we're complete and we have the right flags, then
147 * we flag the user as also having been authenticated
150 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
151 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
152 if (ssh_gssapi_getclient(ctx, &gssapi_client))
153 fatal("Couldn't convert client name");
154 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
155 if (flags && (*flags & GSS_C_GLOBUS_LIMITED_PROXY_FLAG))
164 * This parses an exported name, extracting the mechanism specific portion
165 * to use for ACL checking. It verifies that the name belongs the mechanism
166 * originally selected.
169 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
177 #ifdef GSI /* GSI gss_export_name() is broken. */
178 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
179 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
180 gssapi_gsi_mech.oid.length) == 0)) {
181 name->length = ename->length;
182 name->value = xmalloc(ename->length+1);
183 memcpy(name->value, ename->value, ename->length);
184 return GSS_S_COMPLETE;
189 * Check that ename is long enough for all of the fixed length
190 * header, and that the initial ID bytes are correct
193 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
194 return GSS_S_FAILURE;
197 * Extract the OID, and check it. Here GSSAPI breaks with tradition
198 * and does use the OID type and length bytes. To confuse things
199 * there are two lengths - the first including these, and the
203 oidl = GET_16BIT(tok+2); /* length including next two bytes */
204 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
207 * Check the BER encoding for correct type and length, that the
208 * string is long enough and that the OID matches that in our context
210 if (tok[4] != 0x06 || tok[5] != oidl ||
211 ename->length < oidl+6 ||
212 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
213 return GSS_S_FAILURE;
217 if (ename->length < offset+4)
218 return GSS_S_FAILURE;
220 name->length = GET_32BIT(tok+offset);
223 if (ename->length < offset+name->length)
224 return GSS_S_FAILURE;
226 name->value = xmalloc(name->length+1);
227 memcpy(name->value, tok+offset,name->length);
228 ((char *)name->value)[name->length] = 0;
230 return GSS_S_COMPLETE;
233 /* Extract the client details from a given context. This can only reliably
234 * be called once for a context */
236 /* Privileged (called from accept_secure_ctx) */
238 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
242 gss_buffer_desc ename;
246 while (supported_mechs[i]->name != NULL) {
247 if (supported_mechs[i]->oid.length == ctx->oid->length &&
248 (memcmp(supported_mechs[i]->oid.elements,
249 ctx->oid->elements, ctx->oid->length) == 0))
250 client->mech = supported_mechs[i];
254 if (client->mech == NULL)
255 return GSS_S_FAILURE;
257 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
258 &client->displayname, NULL))) {
259 ssh_gssapi_error(ctx);
263 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
265 ssh_gssapi_error(ctx);
269 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
270 &client->exportedname))) {
274 /* We can't copy this structure, so we just move the pointer to it */
275 client->creds = ctx->client_creds;
276 ctx->client_creds = GSS_C_NO_CREDENTIAL;
280 /* As user - called on fatal/exit */
282 ssh_gssapi_cleanup_creds(void)
284 if (gssapi_client.store.filename != NULL) {
285 /* Unlink probably isn't sufficient */
286 debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
287 unlink(gssapi_client.store.filename);
293 ssh_gssapi_storecreds(void)
295 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
296 (*gssapi_client.mech->storecreds)(&gssapi_client);
298 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
301 /* This allows GSSAPI methods to do things to the childs environment based
302 * on the passed authentication process and credentials.
306 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
309 if (gssapi_client.store.envvar != NULL &&
310 gssapi_client.store.envval != NULL) {
311 debug("Setting %s to %s", gssapi_client.store.envvar,
312 gssapi_client.store.envval);
313 child_set_env(envp, envsizep, gssapi_client.store.envvar,
314 gssapi_client.store.envval);
320 ssh_gssapi_userok(char *user)
324 if (gssapi_client.exportedname.length == 0 ||
325 gssapi_client.exportedname.value == NULL) {
326 debug("No suitable client data");
329 #ifdef GSS_C_GLOBUS_LIMITED_PROXY_FLAG
330 if (limited && options.gsi_allow_limited_proxy != 1) {
331 debug("limited proxy not acceptable for remote login");
335 if (gssapi_client.mech && gssapi_client.mech->userok)
336 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
339 /* Destroy delegated credentials if userok fails */
340 gss_release_buffer(&lmin, &gssapi_client.displayname);
341 gss_release_buffer(&lmin, &gssapi_client.exportedname);
342 gss_release_cred(&lmin, &gssapi_client.creds);
343 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
347 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
353 ssh_gssapi_localname(char **user)
356 if (gssapi_client.displayname.length==0 ||
357 gssapi_client.displayname.value==NULL) {
358 debug("No suitable client data");
361 if (gssapi_client.mech && gssapi_client.mech->localname) {
362 return((*gssapi_client.mech->localname)(&gssapi_client,user));
364 debug("Unknown client authentication type");