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Damien Miller6fd6def2005-11-05 15:07:05 +11001/* $OpenBSD: gss-genr.c,v 1.6 2005/10/13 22:24:31 stevesk Exp $ */
Darren Tucker0efd1552003-08-26 11:49:55 +10002
3/*
4 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
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.
14 *
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.
25 */
26
27#include "includes.h"
28
29#ifdef GSSAPI
30
31#include "xmalloc.h"
32#include "bufaux.h"
Darren Tucker0efd1552003-08-26 11:49:55 +100033#include "log.h"
Damien Miller0425d402003-11-17 22:18:21 +110034#include "ssh2.h"
Darren Tucker0efd1552003-08-26 11:49:55 +100035
36#include "ssh-gss.h"
37
Damien Miller0425d402003-11-17 22:18:21 +110038extern u_char *session_id2;
39extern u_int session_id2_len;
Darren Tucker0efd1552003-08-26 11:49:55 +100040
41/* Check that the OID in a data stream matches that in the context */
42int
43ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
44{
45 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
46 ctx->oid->length == len &&
47 memcmp(ctx->oid->elements, data, len) == 0);
48}
49
50/* Set the contexts OID from a data stream */
51void
52ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
53{
54 if (ctx->oid != GSS_C_NO_OID) {
55 xfree(ctx->oid->elements);
56 xfree(ctx->oid);
57 }
58 ctx->oid = xmalloc(sizeof(gss_OID_desc));
59 ctx->oid->length = len;
60 ctx->oid->elements = xmalloc(len);
61 memcpy(ctx->oid->elements, data, len);
62}
63
64/* Set the contexts OID */
65void
66ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
67{
68 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
69}
70
71/* All this effort to report an error ... */
72void
73ssh_gssapi_error(Gssctxt *ctxt)
74{
75 debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
76}
77
78char *
Damien Miller0dc1bef2005-07-17 17:22:45 +100079ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
80 OM_uint32 *minor_status)
Darren Tucker0efd1552003-08-26 11:49:55 +100081{
82 OM_uint32 lmin;
83 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
84 OM_uint32 ctx;
85 Buffer b;
86 char *ret;
87
88 buffer_init(&b);
89
90 if (major_status != NULL)
91 *major_status = ctxt->major;
92 if (minor_status != NULL)
93 *minor_status = ctxt->minor;
94
95 ctx = 0;
96 /* The GSSAPI error */
97 do {
98 gss_display_status(&lmin, ctxt->major,
99 GSS_C_GSS_CODE, GSS_C_NULL_OID, &ctx, &msg);
100
101 buffer_append(&b, msg.value, msg.length);
102 buffer_put_char(&b, '\n');
103
104 gss_release_buffer(&lmin, &msg);
105 } while (ctx != 0);
106
107 /* The mechanism specific error */
108 do {
109 gss_display_status(&lmin, ctxt->minor,
110 GSS_C_MECH_CODE, GSS_C_NULL_OID, &ctx, &msg);
111
112 buffer_append(&b, msg.value, msg.length);
113 buffer_put_char(&b, '\n');
114
115 gss_release_buffer(&lmin, &msg);
116 } while (ctx != 0);
117
118 buffer_put_char(&b, '\0');
119 ret = xmalloc(buffer_len(&b));
120 buffer_get(&b, ret, buffer_len(&b));
121 buffer_free(&b);
122 return (ret);
123}
124
125/*
126 * Initialise our GSSAPI context. We use this opaque structure to contain all
127 * of the data which both the client and server need to persist across
128 * {accept,init}_sec_context calls, so that when we do it from the userauth
129 * stuff life is a little easier
130 */
131void
132ssh_gssapi_build_ctx(Gssctxt **ctx)
133{
134 *ctx = xmalloc(sizeof (Gssctxt));
135 (*ctx)->major = 0;
136 (*ctx)->minor = 0;
137 (*ctx)->context = GSS_C_NO_CONTEXT;
138 (*ctx)->name = GSS_C_NO_NAME;
139 (*ctx)->oid = GSS_C_NO_OID;
140 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
141 (*ctx)->client = GSS_C_NO_NAME;
142 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
143}
144
145/* Delete our context, providing it has been built correctly */
146void
147ssh_gssapi_delete_ctx(Gssctxt **ctx)
148{
149 OM_uint32 ms;
150
151 if ((*ctx) == NULL)
152 return;
153 if ((*ctx)->context != GSS_C_NO_CONTEXT)
154 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
155 if ((*ctx)->name != GSS_C_NO_NAME)
156 gss_release_name(&ms, &(*ctx)->name);
157 if ((*ctx)->oid != GSS_C_NO_OID) {
158 xfree((*ctx)->oid->elements);
159 xfree((*ctx)->oid);
160 (*ctx)->oid = GSS_C_NO_OID;
161 }
162 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
163 gss_release_cred(&ms, &(*ctx)->creds);
164 if ((*ctx)->client != GSS_C_NO_NAME)
165 gss_release_name(&ms, &(*ctx)->client);
166 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
167 gss_release_cred(&ms, &(*ctx)->client_creds);
168
169 xfree(*ctx);
170 *ctx = NULL;
171}
172
173/*
174 * Wrapper to init_sec_context
175 * Requires that the context contains:
176 * oid
177 * server name (from ssh_gssapi_import_name)
178 */
179OM_uint32
180ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
181 gss_buffer_desc* send_tok, OM_uint32 *flags)
182{
183 int deleg_flag = 0;
184
185 if (deleg_creds) {
186 deleg_flag = GSS_C_DELEG_FLAG;
187 debug("Delegating credentials");
188 }
189
190 ctx->major = gss_init_sec_context(&ctx->minor,
191 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
192 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
193 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
194
195 if (GSS_ERROR(ctx->major))
196 ssh_gssapi_error(ctx);
197
198 return (ctx->major);
199}
200
201/* Create a service name for the given host */
202OM_uint32
203ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
204{
205 gss_buffer_desc gssbuf;
206
207 gssbuf.length = sizeof("host@") + strlen(host);
208 gssbuf.value = xmalloc(gssbuf.length);
209 snprintf(gssbuf.value, gssbuf.length, "host@%s", host);
210
211 if ((ctx->major = gss_import_name(&ctx->minor,
212 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
213 ssh_gssapi_error(ctx);
214
215 xfree(gssbuf.value);
216 return (ctx->major);
217}
218
219/* Acquire credentials for a server running on the current host.
220 * Requires that the context structure contains a valid OID
221 */
222
223/* Returns a GSSAPI error code */
224OM_uint32
225ssh_gssapi_acquire_cred(Gssctxt *ctx)
226{
227 OM_uint32 status;
228 char lname[MAXHOSTNAMELEN];
229 gss_OID_set oidset;
230
231 gss_create_empty_oid_set(&status, &oidset);
232 gss_add_oid_set_member(&status, ctx->oid, &oidset);
233
234 if (gethostname(lname, MAXHOSTNAMELEN))
235 return (-1);
236
237 if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
238 return (ctx->major);
239
240 if ((ctx->major = gss_acquire_cred(&ctx->minor,
241 ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
242 ssh_gssapi_error(ctx);
243
244 gss_release_oid_set(&status, &oidset);
245 return (ctx->major);
246}
247
248OM_uint32
Damien Miller0425d402003-11-17 22:18:21 +1100249ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
250{
251 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
252 GSS_C_QOP_DEFAULT, buffer, hash)))
253 ssh_gssapi_error(ctx);
Damien Miller787b2ec2003-11-21 23:56:47 +1100254
Damien Miller0425d402003-11-17 22:18:21 +1100255 return (ctx->major);
256}
257
258void
Damien Millera8e06ce2003-11-21 23:48:55 +1100259ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
260 const char *context)
Damien Miller787b2ec2003-11-21 23:56:47 +1100261{
Damien Miller0425d402003-11-17 22:18:21 +1100262 buffer_init(b);
263 buffer_put_string(b, session_id2, session_id2_len);
264 buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
265 buffer_put_cstring(b, user);
266 buffer_put_cstring(b, service);
267 buffer_put_cstring(b, context);
268}
269
270OM_uint32
Damien Miller6fd6def2005-11-05 15:07:05 +1100271ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
272{
Darren Tucker0efd1552003-08-26 11:49:55 +1000273 if (*ctx)
274 ssh_gssapi_delete_ctx(ctx);
275 ssh_gssapi_build_ctx(ctx);
276 ssh_gssapi_set_oid(*ctx, oid);
277 return (ssh_gssapi_acquire_cred(*ctx));
278}
279
280#endif /* GSSAPI */