1 /* $OpenBSD: gss-serv.c,v 1.5 2003/11/17 11:06:07 markus 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.
37 #include <openssl/evp.h>
47 #include "monitor_wrap.h"
53 extern ServerOptions options;
54 extern u_char *session_id2;
55 extern int session_id2_len;
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;
66 extern ssh_gssapi_mech gssapi_kerberos_mech_old;
69 extern ssh_gssapi_mech gssapi_gsi_mech;
70 extern ssh_gssapi_mech gssapi_gsi_mech_old;
73 ssh_gssapi_mech* supported_mechs[]= {
75 &gssapi_kerberos_mech,
76 &gssapi_kerberos_mech_old, /* Support for legacy clients */
80 &gssapi_gsi_mech_old, /* Support for legacy clients */
87 ssh_gssapi_supported_oids(gss_OID_set *oidset)
92 gss_OID_set supported;
94 gss_create_empty_oid_set(&min_status, oidset);
95 gss_indicate_mechs(&min_status, &supported);
97 while (supported_mechs[i]->name != NULL) {
98 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
99 &supported_mechs[i]->oid, supported, &present)))
102 gss_add_oid_set_member(&min_status,
103 &supported_mechs[i]->oid, oidset);
109 /* Wrapper around accept_sec_context
110 * Requires that the context contains:
112 * credentials (from ssh_gssapi_acquire_cred)
116 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
117 gss_buffer_desc *send_tok, OM_uint32 *flags)
122 ctx->major = gss_accept_sec_context(&ctx->minor,
123 &ctx->context, ctx->creds, recv_tok,
124 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
125 send_tok, flags, NULL, &ctx->client_creds);
127 if (GSS_ERROR(ctx->major))
128 ssh_gssapi_error(ctx);
130 if (ctx->client_creds)
131 debug("Received some client credentials");
133 debug("Got no client credentials");
137 /* Now, if we're complete and we have the right flags, then
138 * we flag the user as also having been authenticated
141 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
142 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
143 if (ssh_gssapi_getclient(ctx, &gssapi_client))
144 fatal("Couldn't convert client name");
151 * This parses an exported name, extracting the mechanism specific portion
152 * to use for ACL checking. It verifies that the name belongs the mechanism
153 * originally selected.
156 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
164 #ifdef GSI /* GSI gss_export_name() is broken. */
165 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
166 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
167 gssapi_gsi_mech.oid.length) == 0)) {
168 name->length = ename->length;
169 name->value = xmalloc(ename->length+1);
170 memcpy(name->value, ename->value, ename->length);
171 return GSS_S_COMPLETE;
176 * Check that ename is long enough for all of the fixed length
177 * header, and that the initial ID bytes are correct
180 if (ename->length<6 || memcmp(tok,"\x04\x01", 2)!=0)
181 return GSS_S_FAILURE;
184 * Extract the OID, and check it. Here GSSAPI breaks with tradition
185 * and does use the OID type and length bytes. To confuse things
186 * there are two lengths - the first including these, and the
190 oidl = GET_16BIT(tok+2); /* length including next two bytes */
191 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
194 * Check the BER encoding for correct type and length, that the
195 * string is long enough and that the OID matches that in our context
197 if (tok[4] != 0x06 || tok[5] != oidl ||
198 ename->length < oidl+6 ||
199 !ssh_gssapi_check_oid(ctx,tok+6,oidl))
200 return GSS_S_FAILURE;
204 if (ename->length < offset+4)
205 return GSS_S_FAILURE;
207 name->length = GET_32BIT(tok+offset);
210 if (ename->length < offset+name->length)
211 return GSS_S_FAILURE;
213 name->value = xmalloc(name->length+1);
214 memcpy(name->value,tok+offset,name->length);
215 ((char *)name->value)[name->length] = 0;
217 return GSS_S_COMPLETE;
220 /* Extract the client details from a given context. This can only reliably
221 * be called once for a context */
223 /* Priviledged (called from accept_secure_ctx) */
225 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
229 gss_buffer_desc ename;
233 while (supported_mechs[i]->name != NULL) {
234 if (supported_mechs[i]->oid.length == ctx->oid->length &&
235 (memcmp(supported_mechs[i]->oid.elements,
236 ctx->oid->elements, ctx->oid->length) == 0))
237 client->mech = supported_mechs[i];
241 if (client->mech == NULL)
242 return GSS_S_FAILURE;
244 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
245 &client->displayname, NULL))) {
246 ssh_gssapi_error(ctx);
250 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
252 ssh_gssapi_error(ctx);
256 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
257 &client->exportedname))) {
261 /* We can't copy this structure, so we just move the pointer to it */
262 client->creds = ctx->client_creds;
263 ctx->client_creds = GSS_C_NO_CREDENTIAL;
267 /* As user - called on fatal/exit */
269 ssh_gssapi_cleanup_creds(void)
271 if (gssapi_client.store.filename != NULL) {
272 /* Unlink probably isn't sufficient */
273 debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
274 unlink(gssapi_client.store.filename);
280 ssh_gssapi_storecreds(void)
282 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
283 (*gssapi_client.mech->storecreds)(&gssapi_client);
285 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
288 /* This allows GSSAPI methods to do things to the childs environment based
289 * on the passed authentication process and credentials.
293 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
296 if (gssapi_client.store.envvar != NULL &&
297 gssapi_client.store.envval != NULL) {
299 debug("Setting %s to %s", gssapi_client.store.envvar,
300 gssapi_client.store.envval);
301 child_set_env(envp, envsizep, gssapi_client.store.envvar,
302 gssapi_client.store.envval);
308 ssh_gssapi_userok(char *user)
310 if (gssapi_client.exportedname.length == 0 ||
311 gssapi_client.exportedname.value == NULL) {
312 debug("No suitable client data");
315 if (gssapi_client.mech && gssapi_client.mech->userok)
316 return ((*gssapi_client.mech->userok)(&gssapi_client, user));
318 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
322 /* Return a list of the gss-group1-sha1-x mechanisms supported by this
325 * We only support the mechanisms that we've indicated in the list above,
326 * but we check that they're supported by the GSSAPI mechanism on the
327 * machine. We also check, before including them in the list, that
328 * we have the necesary information in order to carry out the key exchange
329 * (that is, that the user has credentials, the server's creds are accessible,
332 * The way that this is done is fairly nasty, as we do a lot of work that
333 * is then thrown away. This should possibly be implemented with a cache
334 * that stores the results (in an expanded Gssctxt structure), which are
335 * then used by the first calls if that key exchange mechanism is chosen.
340 ssh_gssapi_server_mechanisms() {
341 gss_OID_set supported;
343 OM_uint32 maj_status, min_status;
350 if (datafellows & SSH_OLD_GSSAPI) return NULL;
352 ssh_gssapi_supported_oids(&supported);
356 while(supported_mechs[i]->name != NULL) {
357 if ((maj_status=gss_test_oid_set_member(&min_status,
358 &supported_mechs[i]->oid,
365 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
366 &supported_mechs[i]->oid)))) {
367 /* Append gss_group1_sha1_x to our list */
369 buffer_put_char(&buf,',');
370 buffer_append(&buf, KEX_GSS_SHA1,
371 sizeof(KEX_GSS_SHA1)-1);
373 supported_mechs[i]->enc_name,
374 strlen(supported_mechs[i]->enc_name));
375 debug("GSSAPI mechanism %s (%s%s) supported",
376 supported_mechs[i]->name, KEX_GSS_SHA1,
377 supported_mechs[i]->enc_name);
379 debug("no credentials for GSSAPI mechanism %s",
380 supported_mechs[i]->name);
383 debug("GSSAPI mechanism %s not supported",
384 supported_mechs[i]->name);
386 ssh_gssapi_delete_ctx(&ctx);
390 buffer_put_char(&buf,'\0');
392 mechs=xmalloc(buffer_len(&buf));
393 buffer_get(&buf,mechs,buffer_len(&buf));
395 if (strlen(mechs)==0)
401 /* Return the OID that corresponds to the given context name */
405 ssh_gssapi_server_id_kex(char *name) {
408 if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
412 name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
414 while (supported_mechs[i]->name!=NULL &&
415 strcmp(name,supported_mechs[i]->enc_name)!=0) {
419 if (supported_mechs[i]->name==NULL)
422 debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
423 KEX_GSS_SHA1, supported_mechs[i]->enc_name);
425 return &supported_mechs[i]->oid;
430 ssh_gssapi_localname(char **user)
433 if (gssapi_client.displayname.length==0 ||
434 gssapi_client.displayname.value==NULL) {
435 debug("No suitable client data");
438 if (gssapi_client.mech && gssapi_client.mech->localname) {
439 return((*gssapi_client.mech->localname)(&gssapi_client,user));
441 debug("Unknown client authentication type");
448 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
450 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
451 gssbuf, gssmic, NULL);