1 /* $OpenBSD: gss-genr.c,v 1.3 2003/11/21 11:57:03 djm 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.
35 #include <openssl/evp.h>
38 #include "monitor_wrap.h"
44 extern u_char *session_id2;
45 extern u_int session_id2_len;
50 } ssh_gss_kex_mapping;
52 static ssh_gss_kex_mapping *gss_enc2oid;
54 /* Return a list of the gss-group1-sha1-x mechanisms supported by this
57 * On the client side, we don't need to worry about whether we 'know'
58 * about the mechanism or not - we assume that any mechanism that we've been
59 * linked against is suitable for inclusion.
61 * XXX - We might want to make this configurable in the future, so as to
62 * XXX - allow the user control over which mechanisms to use.
66 ssh_gssapi_client_mechanisms(char *host) {
67 gss_OID_set supported;
74 char digest[EVP_MAX_MD_SIZE];
76 const EVP_MD *evp_md = EVP_md5();
80 if (datafellows & SSH_OLD_GSSAPI) return NULL;
82 gss_indicate_mechs(&min_status,&supported);
83 if (datafellows & SSH_BUG_GSSAPI_BER) {
84 gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
85 *((supported->count*2)+1));
87 gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
88 *(supported->count+1));
94 for (i=0;i<supported->count;i++) {
96 gss_enc2oid[oidpos].encoded=NULL;
98 if (supported->elements[i].length<128 &&
99 ssh_gssapi_check_mechanism(&(supported->elements[i]),host)) {
101 /* Earlier versions of this code interpreted the
102 * spec incorrectly with regard to OID encoding. They
103 * also mis-encoded the krb5 OID. The following
104 * _temporary_ code interfaces with these broken
107 if (datafellows & SSH_BUG_GSSAPI_BER) {
109 gss_OID_desc krb5oid={9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"};
110 gss_OID_desc gsioid={9, "\x2B\x06\x01\x04\x01\x9B\x50\x01\x01"};
112 if (supported->elements[i].length==krb5oid.length &&
113 memcmp(supported->elements[i].elements,
114 krb5oid.elements, krb5oid.length)==0) {
115 bodge="Se3H81ismmOC3OE+FwYCiQ==";
118 if (supported->elements[i].length==gsioid.length &&
119 memcmp(supported->elements[i].elements,
120 gsioid.elements, gsioid.length)==0) {
121 bodge="N3+k7/4wGxHyuP8Yxi4RhA==";
126 buffer_put_char(&buf,',');
129 buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
130 buffer_append(&buf, bodge, strlen(bodge));
132 gss_enc2oid[oidpos].oid=&(supported->elements[i]);
133 gss_enc2oid[oidpos].encoded=bodge;
139 /* Add the required DER encoding octets and MD5 hash */
140 deroid[0]=0x06; /* Object Identifier */
141 deroid[1]=supported->elements[i].length;
143 EVP_DigestInit(&md, evp_md);
144 EVP_DigestUpdate(&md,deroid,2);
145 EVP_DigestUpdate(&md,
146 supported->elements[i].elements,
147 supported->elements[i].length);
148 EVP_DigestFinal(&md, digest, NULL);
150 /* Base64 encode it */
151 encoded=xmalloc(EVP_MD_size(evp_md)*2);
152 enclen=__b64_ntop(digest, EVP_MD_size(evp_md),
153 encoded,EVP_MD_size(evp_md)*2);
155 buffer_put_char(&buf,',');
157 buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
158 buffer_append(&buf, encoded, enclen);
160 debug("Mechanism encoded as %s",encoded);
162 gss_enc2oid[oidpos].oid=&(supported->elements[i]);
163 gss_enc2oid[oidpos].encoded=encoded;
167 gss_enc2oid[oidpos].oid=NULL;
168 gss_enc2oid[oidpos].encoded=NULL;
170 buffer_put_char(&buf,'\0');
172 mechs=xmalloc(buffer_len(&buf));
173 buffer_get(&buf,mechs,buffer_len(&buf));
175 if (strlen(mechs)==0)
182 ssh_gssapi_client_id_kex(Gssctxt *ctx, char *name) {
185 if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
189 name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the ID string */
191 while (gss_enc2oid[i].encoded!=NULL &&
192 strcmp(name,gss_enc2oid[i].encoded)!=0) {
196 if (gss_enc2oid[i].oid!=NULL) {
197 ssh_gssapi_set_oid(ctx,gss_enc2oid[i].oid);
200 return gss_enc2oid[i].oid;
203 /* Check that the OID in a data stream matches that in the context */
205 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
207 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
208 ctx->oid->length == len &&
209 memcmp(ctx->oid->elements, data, len) == 0);
212 /* Set the contexts OID from a data stream */
214 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
216 if (ctx->oid != GSS_C_NO_OID) {
217 xfree(ctx->oid->elements);
220 ctx->oid = xmalloc(sizeof(gss_OID_desc));
221 ctx->oid->length = len;
222 ctx->oid->elements = xmalloc(len);
223 memcpy(ctx->oid->elements, data, len);
226 /* Set the contexts OID */
228 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
230 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
233 /* All this effort to report an error ... */
235 ssh_gssapi_error(Gssctxt *ctxt)
237 debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
241 ssh_gssapi_last_error(Gssctxt *ctxt,
242 OM_uint32 *major_status, OM_uint32 *minor_status)
245 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
252 if (major_status != NULL)
253 *major_status = ctxt->major;
254 if (minor_status != NULL)
255 *minor_status = ctxt->minor;
258 /* The GSSAPI error */
260 gss_display_status(&lmin, ctxt->major,
261 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
263 buffer_append(&b, msg.value, msg.length);
264 buffer_put_char(&b, '\n');
266 gss_release_buffer(&lmin, &msg);
269 /* The mechanism specific error */
271 gss_display_status(&lmin, ctxt->minor,
272 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
274 buffer_append(&b, msg.value, msg.length);
275 buffer_put_char(&b, '\n');
277 gss_release_buffer(&lmin, &msg);
280 buffer_put_char(&b, '\0');
281 ret = xmalloc(buffer_len(&b));
282 buffer_get(&b, ret, buffer_len(&b));
288 * Initialise our GSSAPI context. We use this opaque structure to contain all
289 * of the data which both the client and server need to persist across
290 * {accept,init}_sec_context calls, so that when we do it from the userauth
291 * stuff life is a little easier
294 ssh_gssapi_build_ctx(Gssctxt **ctx)
296 *ctx = xmalloc(sizeof (Gssctxt));
299 (*ctx)->context = GSS_C_NO_CONTEXT;
300 (*ctx)->name = GSS_C_NO_NAME;
301 (*ctx)->oid = GSS_C_NO_OID;
302 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
303 (*ctx)->client = GSS_C_NO_NAME;
304 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
307 /* Delete our context, providing it has been built correctly */
309 ssh_gssapi_delete_ctx(Gssctxt **ctx)
311 #if !defined(MECHGLUE)
317 #if !defined(MECHGLUE) /* mechglue has some memory management issues */
318 if ((*ctx)->context != GSS_C_NO_CONTEXT)
319 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
320 if ((*ctx)->name != GSS_C_NO_NAME)
321 gss_release_name(&ms, &(*ctx)->name);
322 if ((*ctx)->oid != GSS_C_NO_OID) {
323 xfree((*ctx)->oid->elements);
325 (*ctx)->oid = GSS_C_NO_OID;
327 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
328 gss_release_cred(&ms, &(*ctx)->creds);
329 if ((*ctx)->client != GSS_C_NO_NAME)
330 gss_release_name(&ms, &(*ctx)->client);
331 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
332 gss_release_cred(&ms, &(*ctx)->client_creds);
340 * Wrapper to init_sec_context
341 * Requires that the context contains:
343 * server name (from ssh_gssapi_import_name)
346 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
347 gss_buffer_desc* send_tok, OM_uint32 *flags)
352 deleg_flag = GSS_C_DELEG_FLAG;
353 debug("Delegating credentials");
356 ctx->major = gss_init_sec_context(&ctx->minor,
357 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
358 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
359 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
361 if (GSS_ERROR(ctx->major))
362 ssh_gssapi_error(ctx);
367 /* Create a service name for the given host */
369 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
371 gss_buffer_desc gssbuf;
374 /* Make a copy of the host name, in case it was returned by a
375 * previous call to gethostbyname(). */
376 xhost = xstrdup(host);
378 /* Make sure we have the FQDN. Some GSSAPI implementations don't do
379 * this for us themselves */
380 resolve_localhost(&xhost);
382 gssbuf.length = sizeof("host@") + strlen(xhost);
383 gssbuf.value = xmalloc(gssbuf.length);
384 snprintf(gssbuf.value, gssbuf.length, "host@%s", xhost);
386 if ((ctx->major = gss_import_name(&ctx->minor,
387 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
388 ssh_gssapi_error(ctx);
395 /* Acquire credentials for a server running on the current host.
396 * Requires that the context structure contains a valid OID
399 /* Returns a GSSAPI error code */
401 ssh_gssapi_acquire_cred(Gssctxt *ctx)
404 char lname[MAXHOSTNAMELEN];
407 gss_create_empty_oid_set(&status, &oidset);
408 gss_add_oid_set_member(&status, ctx->oid, &oidset);
410 if (gethostname(lname, MAXHOSTNAMELEN))
413 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
416 if ((ctx->major = gss_acquire_cred(&ctx->minor,
417 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
418 ssh_gssapi_error(ctx);
420 gss_release_oid_set(&status, &oidset);
425 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
427 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
428 GSS_C_QOP_DEFAULT, buffer, hash)))
429 ssh_gssapi_error(ctx);
435 ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
439 buffer_put_string(b, session_id2, session_id2_len);
440 buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
441 buffer_put_cstring(b, user);
442 buffer_put_cstring(b, service);
443 buffer_put_cstring(b, context);
447 ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
449 ssh_gssapi_delete_ctx(ctx);
450 ssh_gssapi_build_ctx(ctx);
451 ssh_gssapi_set_oid(*ctx, oid);
452 return (ssh_gssapi_acquire_cred(*ctx));
456 ssh_gssapi_check_mechanism(gss_OID oid, char *host) {
457 Gssctxt * ctx = NULL;
458 gss_buffer_desc token;
459 OM_uint32 major,minor;
461 ssh_gssapi_build_ctx(&ctx);
462 ssh_gssapi_set_oid(ctx,oid);
463 ssh_gssapi_import_name(ctx,host);
464 major=ssh_gssapi_init_ctx(ctx,0, GSS_C_NO_BUFFER, &token, NULL);
465 gss_release_buffer(&minor,&token);
466 ssh_gssapi_delete_ctx(&ctx);
467 return(!GSS_ERROR(major));