1 /* $OpenBSD: gss-genr.c,v 1.1 2003/08/22 10:56:09 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.
38 #include <openssl/evp.h>
43 #include "monitor_wrap.h"
53 } ssh_gss_kex_mapping;
55 static ssh_gss_kex_mapping *gss_enc2oid;
57 /* Return a list of the gss-group1-sha1-x mechanisms supported by this
60 * On the client side, we don't need to worry about whether we 'know'
61 * about the mechanism or not - we assume that any mechanism that we've been
62 * linked against is suitable for inclusion.
64 * XXX - We might want to make this configurable in the future, so as to
65 * XXX - allow the user control over which mechanisms to use.
69 ssh_gssapi_client_mechanisms(char *host) {
70 gss_OID_set supported;
77 char digest[EVP_MAX_MD_SIZE];
79 const EVP_MD *evp_md = EVP_md5();
83 if (datafellows & SSH_OLD_GSSAPI) return NULL;
85 gss_indicate_mechs(&min_status,&supported);
86 if (datafellows & SSH_BUG_GSSAPI_BER) {
87 gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
88 *((supported->count*2)+1));
90 gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
91 *(supported->count+1));
97 for (i=0;i<supported->count;i++) {
99 gss_enc2oid[oidpos].encoded=NULL;
101 if (supported->elements[i].length<128 &&
102 ssh_gssapi_check_mechanism(&(supported->elements[i]),host)) {
104 /* Earlier versions of this code interpreted the
105 * spec incorrectly with regard to OID encoding. They
106 * also mis-encoded the krb5 OID. The following
107 * _temporary_ code interfaces with these broken
110 if (datafellows & SSH_BUG_GSSAPI_BER) {
112 gss_OID_desc krb5oid={9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"};
113 gss_OID_desc gsioid={9, "\x2B\x06\x01\x04\x01\x9B\x50\x01\x01"};
115 if (supported->elements[i].length==krb5oid.length &&
116 memcmp(supported->elements[i].elements,
117 krb5oid.elements, krb5oid.length)==0) {
118 bodge="Se3H81ismmOC3OE+FwYCiQ==";
121 if (supported->elements[i].length==gsioid.length &&
122 memcmp(supported->elements[i].elements,
123 gsioid.elements, gsioid.length)==0) {
124 bodge="N3+k7/4wGxHyuP8Yxi4RhA==";
129 buffer_put_char(&buf,',');
132 buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
133 buffer_append(&buf, bodge, strlen(bodge));
135 gss_enc2oid[oidpos].oid=&(supported->elements[i]);
136 gss_enc2oid[oidpos].encoded=bodge;
142 /* Add the required DER encoding octets and MD5 hash */
143 deroid[0]=0x06; /* Object Identifier */
144 deroid[1]=supported->elements[i].length;
146 EVP_DigestInit(&md, evp_md);
147 EVP_DigestUpdate(&md,deroid,2);
148 EVP_DigestUpdate(&md,
149 supported->elements[i].elements,
150 supported->elements[i].length);
151 EVP_DigestFinal(&md, digest, NULL);
153 /* Base64 encode it */
154 encoded=xmalloc(EVP_MD_size(evp_md)*2);
155 enclen=__b64_ntop(digest, EVP_MD_size(evp_md),
156 encoded,EVP_MD_size(evp_md)*2);
158 buffer_put_char(&buf,',');
160 buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
161 buffer_append(&buf, encoded, enclen);
163 debug("Mechanism encoded as %s",encoded);
165 gss_enc2oid[oidpos].oid=&(supported->elements[i]);
166 gss_enc2oid[oidpos].encoded=encoded;
170 gss_enc2oid[oidpos].oid=NULL;
171 gss_enc2oid[oidpos].encoded=NULL;
173 buffer_put_char(&buf,'\0');
175 mechs=xmalloc(buffer_len(&buf));
176 buffer_get(&buf,mechs,buffer_len(&buf));
178 if (strlen(mechs)==0)
185 ssh_gssapi_client_id_kex(Gssctxt *ctx, char *name) {
188 if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
192 name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the ID string */
194 while (gss_enc2oid[i].encoded!=NULL &&
195 strcmp(name,gss_enc2oid[i].encoded)!=0) {
199 if (gss_enc2oid[i].oid!=NULL) {
200 ssh_gssapi_set_oid(ctx,gss_enc2oid[i].oid);
203 return gss_enc2oid[i].oid;
206 /* Check that the OID in a data stream matches that in the context */
208 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
210 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
211 ctx->oid->length == len &&
212 memcmp(ctx->oid->elements, data, len) == 0);
215 /* Set the contexts OID from a data stream */
217 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
219 if (ctx->oid != GSS_C_NO_OID) {
220 xfree(ctx->oid->elements);
223 ctx->oid = xmalloc(sizeof(gss_OID_desc));
224 ctx->oid->length = len;
225 ctx->oid->elements = xmalloc(len);
226 memcpy(ctx->oid->elements, data, len);
229 /* Set the contexts OID */
231 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
233 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
236 /* All this effort to report an error ... */
238 ssh_gssapi_error(Gssctxt *ctxt)
240 debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
244 ssh_gssapi_last_error(Gssctxt *ctxt,
245 OM_uint32 *major_status, OM_uint32 *minor_status)
248 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
255 if (major_status != NULL)
256 *major_status = ctxt->major;
257 if (minor_status != NULL)
258 *minor_status = ctxt->minor;
261 /* The GSSAPI error */
263 gss_display_status(&lmin, ctxt->major,
264 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
266 buffer_append(&b, msg.value, msg.length);
267 buffer_put_char(&b, '\n');
269 gss_release_buffer(&lmin, &msg);
272 /* The mechanism specific error */
274 gss_display_status(&lmin, ctxt->minor,
275 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
277 buffer_append(&b, msg.value, msg.length);
278 buffer_put_char(&b, '\n');
280 gss_release_buffer(&lmin, &msg);
283 buffer_put_char(&b, '\0');
284 ret = xmalloc(buffer_len(&b));
285 buffer_get(&b, ret, buffer_len(&b));
291 * Initialise our GSSAPI context. We use this opaque structure to contain all
292 * of the data which both the client and server need to persist across
293 * {accept,init}_sec_context calls, so that when we do it from the userauth
294 * stuff life is a little easier
297 ssh_gssapi_build_ctx(Gssctxt **ctx)
299 *ctx = xmalloc(sizeof (Gssctxt));
302 (*ctx)->context = GSS_C_NO_CONTEXT;
303 (*ctx)->name = GSS_C_NO_NAME;
304 (*ctx)->oid = GSS_C_NO_OID;
305 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
306 (*ctx)->client = GSS_C_NO_NAME;
307 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
310 /* Delete our context, providing it has been built correctly */
312 ssh_gssapi_delete_ctx(Gssctxt **ctx)
314 #if !defined(MECHGLUE)
320 #if !defined(MECHGLUE) /* mechglue has some memory management issues */
321 if ((*ctx)->context != GSS_C_NO_CONTEXT)
322 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
323 if ((*ctx)->name != GSS_C_NO_NAME)
324 gss_release_name(&ms, &(*ctx)->name);
325 if ((*ctx)->oid != GSS_C_NO_OID) {
326 xfree((*ctx)->oid->elements);
328 (*ctx)->oid = GSS_C_NO_OID;
330 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
331 gss_release_cred(&ms, &(*ctx)->creds);
332 if ((*ctx)->client != GSS_C_NO_NAME)
333 gss_release_name(&ms, &(*ctx)->client);
334 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
335 gss_release_cred(&ms, &(*ctx)->client_creds);
343 * Wrapper to init_sec_context
344 * Requires that the context contains:
346 * server name (from ssh_gssapi_import_name)
349 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
350 gss_buffer_desc* send_tok, OM_uint32 *flags)
355 deleg_flag = GSS_C_DELEG_FLAG;
356 debug("Delegating credentials");
359 ctx->major = gss_init_sec_context(&ctx->minor,
360 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
361 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
362 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
364 if (GSS_ERROR(ctx->major))
365 ssh_gssapi_error(ctx);
370 /* Create a service name for the given host */
372 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
374 gss_buffer_desc gssbuf;
377 /* Make a copy of the host name, in case it was returned by a
378 * previous call to gethostbyname(). */
379 xhost = xstrdup(host);
381 /* Make sure we have the FQDN. Some GSSAPI implementations don't do
382 * this for us themselves */
383 resolve_localhost(&xhost);
385 gssbuf.length = sizeof("host@") + strlen(xhost);
386 gssbuf.value = xmalloc(gssbuf.length);
387 snprintf(gssbuf.value, gssbuf.length, "host@%s", host);
389 if ((ctx->major = gss_import_name(&ctx->minor,
390 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
391 ssh_gssapi_error(ctx);
398 /* Acquire credentials for a server running on the current host.
399 * Requires that the context structure contains a valid OID
402 /* Returns a GSSAPI error code */
404 ssh_gssapi_acquire_cred(Gssctxt *ctx)
407 char lname[MAXHOSTNAMELEN];
410 gss_create_empty_oid_set(&status, &oidset);
411 gss_add_oid_set_member(&status, ctx->oid, &oidset);
413 if (gethostname(lname, MAXHOSTNAMELEN))
416 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
419 if ((ctx->major = gss_acquire_cred(&ctx->minor,
420 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
421 ssh_gssapi_error(ctx);
423 gss_release_oid_set(&status, &oidset);
428 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
430 ssh_gssapi_delete_ctx(ctx);
431 ssh_gssapi_build_ctx(ctx);
432 ssh_gssapi_set_oid(*ctx, oid);
433 return (ssh_gssapi_acquire_cred(*ctx));
437 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *buffer, gss_buffer_desc *hash) {
439 if ((ctx->major=gss_get_mic(&ctx->minor,ctx->context,
440 GSS_C_QOP_DEFAULT, buffer, hash))) {
441 ssh_gssapi_error(ctx);
448 ssh_gssapi_check_mechanism(gss_OID oid, char *host) {
449 Gssctxt * ctx = NULL;
450 gss_buffer_desc token;
451 OM_uint32 major,minor;
453 ssh_gssapi_build_ctx(&ctx);
454 ssh_gssapi_set_oid(ctx,oid);
455 ssh_gssapi_import_name(ctx,host);
456 major=ssh_gssapi_init_ctx(ctx,0, GSS_C_NO_BUFFER, &token, NULL);
457 gss_release_buffer(&minor,&token);
458 ssh_gssapi_delete_ctx(&ctx);
459 return(!GSS_ERROR(major));