1 /* $OpenBSD: gss-genr.c,v 1.6 2005/10/13 22:24:31 stevesk Exp $ */
4 * Copyright (c) 2001-2005 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.
35 #include <openssl/evp.h>
38 #include "monitor_wrap.h"
41 #include <openssl/evp.h>
45 extern u_char *session_id2;
46 extern u_int session_id2_len;
51 } ssh_gss_kex_mapping;
54 * XXX - It would be nice to find a more elegant way of handling the
55 * XXX passing of the key exchange context to the userauth routines
58 Gssctxt *gss_kex_context = NULL;
60 static ssh_gss_kex_mapping *gss_enc2oid = NULL;
63 ssh_gssapi_oid_table_ok() {
64 return (gss_enc2oid != NULL);
68 * Return a list of the gss-group1-sha1 mechanisms supported by this program
70 * We test mechanisms to ensure that we can use them, to avoid starting
71 * a key exchange with a bad mechanism
76 ssh_gssapi_client_mechanisms(const char *host) {
77 gss_OID_set gss_supported;
80 gss_indicate_mechs(&min_status, &gss_supported);
82 return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
87 ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
92 char *mechs, *encoded;
93 unsigned char digest[EVP_MAX_MD_SIZE];
95 const EVP_MD *evp_md = EVP_md5();
98 if (gss_enc2oid != NULL) {
99 for (i=0;gss_enc2oid[i].encoded!=NULL;i++)
100 xfree(gss_enc2oid[i].encoded);
104 gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping)*
105 (gss_supported->count+1));
110 for (i = 0;i < gss_supported->count;i++) {
111 if (gss_supported->elements[i].length < 128 &&
112 (*check)(&(gss_supported->elements[i]), data)) {
114 deroid[0] = SSH_GSS_OIDTYPE;
115 deroid[1] = gss_supported->elements[i].length;
117 EVP_DigestInit(&md, evp_md);
118 EVP_DigestUpdate(&md, deroid, 2);
119 EVP_DigestUpdate(&md,
120 gss_supported->elements[i].elements,
121 gss_supported->elements[i].length);
122 EVP_DigestFinal(&md, digest, NULL);
124 encoded = xmalloc(EVP_MD_size(evp_md)*2);
125 enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
126 encoded, EVP_MD_size(evp_md)*2);
129 buffer_put_char(&buf, ',');
131 buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
132 sizeof(KEX_GSS_GEX_SHA1_ID)-1);
133 buffer_append(&buf, encoded, enclen);
134 buffer_put_char(&buf,',');
135 buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
136 sizeof(KEX_GSS_GRP1_SHA1_ID)-1);
137 buffer_append(&buf, encoded, enclen);
139 gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
140 gss_enc2oid[oidpos].encoded = encoded;
144 gss_enc2oid[oidpos].oid = NULL;
145 gss_enc2oid[oidpos].encoded = NULL;
147 buffer_put_char(&buf, '\0');
149 mechs = xmalloc(buffer_len(&buf));
150 buffer_get(&buf, mechs, buffer_len(&buf));
153 if (strlen(mechs) == 0) {
162 ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int *gex) {
165 if (strncmp(name, KEX_GSS_GRP1_SHA1_ID,
166 sizeof(KEX_GSS_GRP1_SHA1_ID)-1) == 0) {
167 name+=sizeof(KEX_GSS_GRP1_SHA1_ID)-1;
169 } else if (strncmp(name, KEX_GSS_GEX_SHA1_ID,
170 sizeof(KEX_GSS_GEX_SHA1_ID)-1) == 0) {
171 name+=sizeof(KEX_GSS_GEX_SHA1_ID)-1;
177 while (gss_enc2oid[i].encoded != NULL &&
178 strcmp(name, gss_enc2oid[i].encoded) != 0) {
182 if (gss_enc2oid[i].oid != NULL && ctx != NULL)
183 ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
185 return gss_enc2oid[i].oid;
188 /* Check that the OID in a data stream matches that in the context */
190 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
192 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
193 ctx->oid->length == len &&
194 memcmp(ctx->oid->elements, data, len) == 0);
197 /* Set the contexts OID from a data stream */
199 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
201 if (ctx->oid != GSS_C_NO_OID) {
202 xfree(ctx->oid->elements);
205 ctx->oid = xmalloc(sizeof(gss_OID_desc));
206 ctx->oid->length = len;
207 ctx->oid->elements = xmalloc(len);
208 memcpy(ctx->oid->elements, data, len);
211 /* Set the contexts OID */
213 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
215 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
218 /* All this effort to report an error ... */
220 ssh_gssapi_error(Gssctxt *ctxt)
222 debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
226 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
227 OM_uint32 *minor_status)
230 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
237 if (major_status != NULL)
238 *major_status = ctxt->major;
239 if (minor_status != NULL)
240 *minor_status = ctxt->minor;
243 /* The GSSAPI error */
245 gss_display_status(&lmin, ctxt->major,
246 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
248 buffer_append(&b, msg.value, msg.length);
249 buffer_put_char(&b, '\n');
251 gss_release_buffer(&lmin, &msg);
254 /* The mechanism specific error */
256 gss_display_status(&lmin, ctxt->minor,
257 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
259 buffer_append(&b, msg.value, msg.length);
260 buffer_put_char(&b, '\n');
262 gss_release_buffer(&lmin, &msg);
265 buffer_put_char(&b, '\0');
266 ret = xmalloc(buffer_len(&b));
267 buffer_get(&b, ret, buffer_len(&b));
273 * Initialise our GSSAPI context. We use this opaque structure to contain all
274 * of the data which both the client and server need to persist across
275 * {accept,init}_sec_context calls, so that when we do it from the userauth
276 * stuff life is a little easier
279 ssh_gssapi_build_ctx(Gssctxt **ctx)
281 *ctx = xmalloc(sizeof (Gssctxt));
284 (*ctx)->context = GSS_C_NO_CONTEXT;
285 (*ctx)->name = GSS_C_NO_NAME;
286 (*ctx)->oid = GSS_C_NO_OID;
287 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
288 (*ctx)->client = GSS_C_NO_NAME;
289 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
292 /* Delete our context, providing it has been built correctly */
294 ssh_gssapi_delete_ctx(Gssctxt **ctx)
296 #if !defined(MECHGLUE)
302 #if !defined(MECHGLUE) /* mechglue has some memory management issues */
303 if ((*ctx)->context != GSS_C_NO_CONTEXT)
304 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
305 if ((*ctx)->name != GSS_C_NO_NAME)
306 gss_release_name(&ms, &(*ctx)->name);
307 if ((*ctx)->oid != GSS_C_NO_OID) {
308 xfree((*ctx)->oid->elements);
310 (*ctx)->oid = GSS_C_NO_OID;
312 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
313 gss_release_cred(&ms, &(*ctx)->creds);
314 if ((*ctx)->client != GSS_C_NO_NAME)
315 gss_release_name(&ms, &(*ctx)->client);
316 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
317 gss_release_cred(&ms, &(*ctx)->client_creds);
325 * Wrapper to init_sec_context
326 * Requires that the context contains:
328 * server name (from ssh_gssapi_import_name)
331 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
332 gss_buffer_desc* send_tok, OM_uint32 *flags)
337 deleg_flag = GSS_C_DELEG_FLAG;
338 debug("Delegating credentials");
341 ctx->major = gss_init_sec_context(&ctx->minor,
342 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
343 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
344 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
346 if (GSS_ERROR(ctx->major))
347 ssh_gssapi_error(ctx);
352 /* Create a service name for the given host */
354 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
356 gss_buffer_desc gssbuf;
359 /* Make a copy of the host name, in case it was returned by a
360 * previous call to gethostbyname(). */
361 xhost = xstrdup(host);
363 /* Make sure we have the FQDN. Some GSSAPI implementations don't do
364 * this for us themselves */
365 resolve_localhost(&xhost);
367 gssbuf.length = sizeof("host@") + strlen(xhost);
368 gssbuf.value = xmalloc(gssbuf.length);
369 snprintf(gssbuf.value, gssbuf.length, "host@%s", xhost);
371 if ((ctx->major = gss_import_name(&ctx->minor,
372 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
373 ssh_gssapi_error(ctx);
380 /* Acquire credentials for a server running on the current host.
381 * Requires that the context structure contains a valid OID
384 /* Returns a GSSAPI error code */
386 ssh_gssapi_acquire_cred(Gssctxt *ctx)
389 char lname[MAXHOSTNAMELEN];
392 gss_create_empty_oid_set(&status, &oidset);
393 gss_add_oid_set_member(&status, ctx->oid, &oidset);
395 if (gethostname(lname, MAXHOSTNAMELEN))
398 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
401 if ((ctx->major = gss_acquire_cred(&ctx->minor,
402 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
403 ssh_gssapi_error(ctx);
405 gss_release_oid_set(&status, &oidset);
410 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
415 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
416 GSS_C_QOP_DEFAULT, buffer, hash)))
417 ssh_gssapi_error(ctx);
422 /* Priviledged when used by server */
424 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
429 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
430 gssbuf, gssmic, NULL);
436 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
440 buffer_put_string(b, session_id2, session_id2_len);
441 buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
442 buffer_put_cstring(b, user);
443 buffer_put_cstring(b, service);
444 buffer_put_cstring(b, context);
448 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
451 ssh_gssapi_delete_ctx(ctx);
452 ssh_gssapi_build_ctx(ctx);
453 ssh_gssapi_set_oid(*ctx, oid);
454 return (ssh_gssapi_acquire_cred(*ctx));
458 ssh_gssapi_check_mechanism(gss_OID oid, void *host) {
459 Gssctxt * ctx = NULL;
460 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
461 OM_uint32 major, minor;
463 ssh_gssapi_build_ctx(&ctx);
464 ssh_gssapi_set_oid(ctx, oid);
465 ssh_gssapi_import_name(ctx, host);
466 major = ssh_gssapi_init_ctx(ctx, 0, GSS_C_NO_BUFFER, &token, NULL);
467 gss_release_buffer(&minor, &token);
468 ssh_gssapi_delete_ctx(&ctx);
469 return (!GSS_ERROR(major));