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.
34 #include <openssl/evp.h>
41 #include "monitor_wrap.h"
47 extern ServerOptions options;
48 extern u_char *session_id2;
49 extern int session_id2_len;
51 static ssh_gssapi_client gssapi_client =
52 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
53 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
55 ssh_gssapi_mech gssapi_null_mech =
56 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
59 extern ssh_gssapi_mech gssapi_kerberos_mech;
60 extern ssh_gssapi_mech gssapi_kerberos_mech_old;
63 extern ssh_gssapi_mech gssapi_gsi_mech;
64 extern ssh_gssapi_mech gssapi_gsi_mech_old;
67 ssh_gssapi_mech* supported_mechs[]= {
69 &gssapi_kerberos_mech,
70 &gssapi_kerberos_mech_old, /* Support for legacy clients */
74 &gssapi_gsi_mech_old, /* Support for legacy clients */
81 ssh_gssapi_supported_oids(gss_OID_set *oidset)
86 gss_OID_set supported;
88 gss_create_empty_oid_set(&min_status, oidset);
89 /* Ask priviledged process what mechanisms it supports. */
90 PRIVSEP(gss_indicate_mechs(&min_status, &supported));
92 while (supported_mechs[i]->name != NULL) {
93 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
94 &supported_mechs[i]->oid, supported, &present)))
97 gss_add_oid_set_member(&min_status,
98 &supported_mechs[i]->oid, oidset);
104 /* Wrapper around accept_sec_context
105 * Requires that the context contains:
107 * credentials (from ssh_gssapi_acquire_cred)
111 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
112 gss_buffer_desc *send_tok, OM_uint32 *flags)
117 ctx->major = gss_accept_sec_context(&ctx->minor,
118 &ctx->context, ctx->creds, recv_tok,
119 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
120 send_tok, flags, NULL, &ctx->client_creds);
122 if (GSS_ERROR(ctx->major))
123 ssh_gssapi_error(ctx);
125 if (ctx->client_creds)
126 debug("Received some client credentials");
128 debug("Got no client credentials");
132 /* Now, if we're complete and we have the right flags, then
133 * we flag the user as also having been authenticated
136 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
137 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
138 if (ssh_gssapi_getclient(ctx, &gssapi_client))
139 fatal("Couldn't convert client name");
146 * This parses an exported name, extracting the mechanism specific portion
147 * to use for ACL checking. It verifies that the name belongs the mechanism
148 * originally selected.
151 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
159 #ifdef GSI /* GSI gss_export_name() is broken. */
160 if ((ctx->oid->length == gssapi_gsi_mech.oid.length) &&
161 (memcmp(ctx->oid->elements, gssapi_gsi_mech.oid.elements,
162 gssapi_gsi_mech.oid.length) == 0)) {
163 name->length = ename->length;
164 name->value = xmalloc(ename->length+1);
165 memcpy(name->value, ename->value, ename->length);
166 return GSS_S_COMPLETE;
171 * Check that ename is long enough for all of the fixed length
172 * header, and that the initial ID bytes are correct
175 if (ename->length<6 || memcmp(tok,"\x04\x01", 2)!=0)
176 return GSS_S_FAILURE;
179 * Extract the OID, and check it. Here GSSAPI breaks with tradition
180 * and does use the OID type and length bytes. To confuse things
181 * there are two lengths - the first including these, and the
185 oidl = GET_16BIT(tok+2); /* length including next two bytes */
186 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
189 * Check the BER encoding for correct type and length, that the
190 * string is long enough and that the OID matches that in our context
192 if (tok[4] != 0x06 || tok[5] != oidl ||
193 ename->length < oidl+6 ||
194 !ssh_gssapi_check_oid(ctx,tok+6,oidl))
195 return GSS_S_FAILURE;
199 if (ename->length < offset+4)
200 return GSS_S_FAILURE;
202 name->length = GET_32BIT(tok+offset);
205 if (ename->length < offset+name->length)
206 return GSS_S_FAILURE;
208 name->value = xmalloc(name->length+1);
209 memcpy(name->value,tok+offset,name->length);
210 ((char *)name->value)[name->length] = 0;
212 return GSS_S_COMPLETE;
215 /* Extract the client details from a given context. This can only reliably
216 * be called once for a context */
218 /* Priviledged (called from accept_secure_ctx) */
220 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
224 gss_buffer_desc ename;
228 while (supported_mechs[i]->name != NULL) {
229 if (supported_mechs[i]->oid.length == ctx->oid->length &&
230 (memcmp(supported_mechs[i]->oid.elements,
231 ctx->oid->elements, ctx->oid->length) == 0))
232 client->mech = supported_mechs[i];
236 if (client->mech == NULL)
237 return GSS_S_FAILURE;
239 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
240 &client->displayname, NULL))) {
241 ssh_gssapi_error(ctx);
245 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
247 ssh_gssapi_error(ctx);
251 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
252 &client->exportedname))) {
256 /* We can't copy this structure, so we just move the pointer to it */
257 client->creds = ctx->client_creds;
258 ctx->client_creds = GSS_C_NO_CREDENTIAL;
262 /* As user - called on fatal/exit */
264 ssh_gssapi_cleanup_creds(void)
266 if (gssapi_client.store.filename != NULL) {
267 /* Unlink probably isn't sufficient */
268 debug("removing gssapi cred file\"%s\"", gssapi_client.store.filename);
269 unlink(gssapi_client.store.filename);
275 ssh_gssapi_storecreds(void)
277 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
278 (*gssapi_client.mech->storecreds)(&gssapi_client);
280 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
283 /* This allows GSSAPI methods to do things to the childs environment based
284 * on the passed authentication process and credentials.
288 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
291 if (gssapi_client.store.envvar != NULL &&
292 gssapi_client.store.envval != NULL) {
294 debug("Setting %s to %s", gssapi_client.store.envvar,
295 gssapi_client.store.envval);
296 child_set_env(envp, envsizep, gssapi_client.store.envvar,
297 gssapi_client.store.envval);
303 ssh_gssapi_userok(char *user)
305 if (gssapi_client.exportedname.length == 0 ||
306 gssapi_client.exportedname.value == NULL) {
307 debug("No suitable client data");
310 if (gssapi_client.mech && gssapi_client.mech->userok)
311 return ((*gssapi_client.mech->userok)(&gssapi_client, user));
313 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
317 /* Return a list of the gss-group1-sha1-x mechanisms supported by this
320 * We only support the mechanisms that we've indicated in the list above,
321 * but we check that they're supported by the GSSAPI mechanism on the
322 * machine. We also check, before including them in the list, that
323 * we have the necesary information in order to carry out the key exchange
324 * (that is, that the user has credentials, the server's creds are accessible,
327 * The way that this is done is fairly nasty, as we do a lot of work that
328 * is then thrown away. This should possibly be implemented with a cache
329 * that stores the results (in an expanded Gssctxt structure), which are
330 * then used by the first calls if that key exchange mechanism is chosen.
335 ssh_gssapi_server_mechanisms() {
336 gss_OID_set supported;
338 OM_uint32 maj_status, min_status;
345 if (datafellows & SSH_OLD_GSSAPI) return NULL;
347 ssh_gssapi_supported_oids(&supported);
351 while(supported_mechs[i]->name != NULL) {
352 if ((maj_status=gss_test_oid_set_member(&min_status,
353 &supported_mechs[i]->oid,
360 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx,
361 &supported_mechs[i]->oid)))) {
362 /* Append gss_group1_sha1_x to our list */
364 buffer_put_char(&buf,',');
365 buffer_append(&buf, KEX_GSS_SHA1,
366 sizeof(KEX_GSS_SHA1)-1);
368 supported_mechs[i]->enc_name,
369 strlen(supported_mechs[i]->enc_name));
370 debug("GSSAPI mechanism %s (%s%s) supported",
371 supported_mechs[i]->name, KEX_GSS_SHA1,
372 supported_mechs[i]->enc_name);
374 debug("no credentials for GSSAPI mechanism %s",
375 supported_mechs[i]->name);
378 debug("GSSAPI mechanism %s not supported",
379 supported_mechs[i]->name);
381 ssh_gssapi_delete_ctx(&ctx);
385 buffer_put_char(&buf,'\0');
387 mechs=xmalloc(buffer_len(&buf));
388 buffer_get(&buf,mechs,buffer_len(&buf));
390 if (strlen(mechs)==0)
396 /* Return the OID that corresponds to the given context name */
400 ssh_gssapi_server_id_kex(char *name) {
403 if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
407 name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the MIME string */
409 while (supported_mechs[i]->name!=NULL &&
410 strcmp(name,supported_mechs[i]->enc_name)!=0) {
414 if (supported_mechs[i]->name==NULL)
417 debug("using GSSAPI mechanism %s (%s%s)", supported_mechs[i]->name,
418 KEX_GSS_SHA1, supported_mechs[i]->enc_name);
420 return &supported_mechs[i]->oid;
425 ssh_gssapi_localname(char **user)
428 if (gssapi_client.displayname.length==0 ||
429 gssapi_client.displayname.value==NULL) {
430 debug("No suitable client data");
433 if (gssapi_client.mech && gssapi_client.mech->localname) {
434 return((*gssapi_client.mech->localname)(&gssapi_client,user));
436 debug("Unknown client authentication type");
443 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
445 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
446 gssbuf, gssmic, NULL);