1/* $OpenBSD: gss-serv.c,v 1.20 2006/08/03 03:34:42 deraadt Exp $ */
2
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 <sys/types.h>
32
33#include <stdarg.h>
34#include <string.h>
35#include <unistd.h>
36
37#include "xmalloc.h"
38#include "buffer.h"
39#include "key.h"
40#include "hostfile.h"
41#include "auth.h"
42#include "log.h"
43#include "channels.h"
44#include "session.h"
45#include "misc.h"
46
47#include "ssh-gss.h"
48
49static ssh_gssapi_client gssapi_client =
50 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
51 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
52
53ssh_gssapi_mech gssapi_null_mech =
54 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
55
56#ifdef KRB5
57extern ssh_gssapi_mech gssapi_kerberos_mech;
58#endif
59
60ssh_gssapi_mech* supported_mechs[]= {
61#ifdef KRB5
62 &gssapi_kerberos_mech,
63#endif
64 &gssapi_null_mech,
65};
66
67/* Unprivileged */
68void
69ssh_gssapi_supported_oids(gss_OID_set *oidset)
70{
71 int i = 0;
72 OM_uint32 min_status;
73 int present;
74 gss_OID_set supported;
75
76 gss_create_empty_oid_set(&min_status, oidset);
77 gss_indicate_mechs(&min_status, &supported);
78
79 while (supported_mechs[i]->name != NULL) {
80 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
81 &supported_mechs[i]->oid, supported, &present)))
82 present = 0;
83 if (present)
84 gss_add_oid_set_member(&min_status,
85 &supported_mechs[i]->oid, oidset);
86 i++;
87 }
88
89 gss_release_oid_set(&min_status, &supported);
90}
91
92
93/* Wrapper around accept_sec_context
94 * Requires that the context contains:
95 * oid
96 * credentials (from ssh_gssapi_acquire_cred)
97 */
98/* Privileged */
99OM_uint32
100ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
101 gss_buffer_desc *send_tok, OM_uint32 *flags)
102{
103 OM_uint32 status;
104 gss_OID mech;
105
106 ctx->major = gss_accept_sec_context(&ctx->minor,
107 &ctx->context, ctx->creds, recv_tok,
108 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
109 send_tok, flags, NULL, &ctx->client_creds);
110
111 if (GSS_ERROR(ctx->major))
112 ssh_gssapi_error(ctx);
113
114 if (ctx->client_creds)
115 debug("Received some client credentials");
116 else
117 debug("Got no client credentials");
118
119 status = ctx->major;
120
121 /* Now, if we're complete and we have the right flags, then
122 * we flag the user as also having been authenticated
123 */
124
125 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
126 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
127 if (ssh_gssapi_getclient(ctx, &gssapi_client))
128 fatal("Couldn't convert client name");
129 }
130
131 return (status);
132}
133
134/*
135 * This parses an exported name, extracting the mechanism specific portion
136 * to use for ACL checking. It verifies that the name belongs the mechanism
137 * originally selected.
138 */
139static OM_uint32
140ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
141{
142 u_char *tok;
143 OM_uint32 offset;
144 OM_uint32 oidl;
145
146 tok = ename->value;
147
148 /*
149 * Check that ename is long enough for all of the fixed length
150 * header, and that the initial ID bytes are correct
151 */
152
153 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
154 return GSS_S_FAILURE;
155
156 /*
157 * Extract the OID, and check it. Here GSSAPI breaks with tradition
158 * and does use the OID type and length bytes. To confuse things
159 * there are two lengths - the first including these, and the
160 * second without.
161 */
162
163 oidl = get_u16(tok+2); /* length including next two bytes */
164 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
165
166 /*
167 * Check the BER encoding for correct type and length, that the
168 * string is long enough and that the OID matches that in our context
169 */
170 if (tok[4] != 0x06 || tok[5] != oidl ||
171 ename->length < oidl+6 ||
172 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
173 return GSS_S_FAILURE;
174
175 offset = oidl+6;
176
177 if (ename->length < offset+4)
178 return GSS_S_FAILURE;
179
180 name->length = get_u32(tok+offset);
181 offset += 4;
182
183 if (ename->length < offset+name->length)
184 return GSS_S_FAILURE;
185
186 name->value = xmalloc(name->length+1);
187 memcpy(name->value, tok+offset, name->length);
188 ((char *)name->value)[name->length] = 0;
189
190 return GSS_S_COMPLETE;
191}
192
193/* Extract the client details from a given context. This can only reliably
194 * be called once for a context */
195
196/* Privileged (called from accept_secure_ctx) */
197OM_uint32
198ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
199{
200 int i = 0;
201
202 gss_buffer_desc ename;
203
204 client->mech = NULL;
205
206 while (supported_mechs[i]->name != NULL) {
207 if (supported_mechs[i]->oid.length == ctx->oid->length &&
208 (memcmp(supported_mechs[i]->oid.elements,
209 ctx->oid->elements, ctx->oid->length) == 0))
210 client->mech = supported_mechs[i];
211 i++;
212 }
213
214 if (client->mech == NULL)
215 return GSS_S_FAILURE;
216
217 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
218 &client->displayname, NULL))) {
219 ssh_gssapi_error(ctx);
220 return (ctx->major);
221 }
222
223 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
224 &ename))) {
225 ssh_gssapi_error(ctx);
226 return (ctx->major);
227 }
228
229 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
230 &client->exportedname))) {
231 return (ctx->major);
232 }
233
234 /* We can't copy this structure, so we just move the pointer to it */
235 client->creds = ctx->client_creds;
236 ctx->client_creds = GSS_C_NO_CREDENTIAL;
237 return (ctx->major);
238}
239
240/* As user - called on fatal/exit */
241void
242ssh_gssapi_cleanup_creds(void)
243{
244 if (gssapi_client.store.filename != NULL) {
245 /* Unlink probably isn't sufficient */
246 debug("removing gssapi cred file\"%s\"",
247 gssapi_client.store.filename);
248 unlink(gssapi_client.store.filename);
249 }
250}
251
252/* As user */
253void
254ssh_gssapi_storecreds(void)
255{
256 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
257 (*gssapi_client.mech->storecreds)(&gssapi_client);
258 } else
259 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
260}
261
262/* This allows GSSAPI methods to do things to the childs environment based
263 * on the passed authentication process and credentials.
264 */
265/* As user */
266void
267ssh_gssapi_do_child(char ***envp, u_int *envsizep)
268{
269
270 if (gssapi_client.store.envvar != NULL &&
271 gssapi_client.store.envval != NULL) {
272 debug("Setting %s to %s", gssapi_client.store.envvar,
273 gssapi_client.store.envval);
274 child_set_env(envp, envsizep, gssapi_client.store.envvar,
275 gssapi_client.store.envval);
276 }
277}
278
279/* Privileged */
280int
281ssh_gssapi_userok(char *user)
282{
283 OM_uint32 lmin;
284
285 if (gssapi_client.exportedname.length == 0 ||
286 gssapi_client.exportedname.value == NULL) {
287 debug("No suitable client data");
288 return 0;
289 }
290 if (gssapi_client.mech && gssapi_client.mech->userok)
291 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
292 return 1;
293 else {
294 /* Destroy delegated credentials if userok fails */
295 gss_release_buffer(&lmin, &gssapi_client.displayname);
296 gss_release_buffer(&lmin, &gssapi_client.exportedname);
297 gss_release_cred(&lmin, &gssapi_client.creds);
298 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
299 return 0;
300 }
301 else
302 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
303 return (0);
304}
305
306/* Privileged */
307OM_uint32
308ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
309{
310 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
311 gssbuf, gssmic, NULL);
312
313 return (ctx->major);
314}
315
316#endif
2
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 <sys/types.h>
32
33#include <stdarg.h>
34#include <string.h>
35#include <unistd.h>
36
37#include "xmalloc.h"
38#include "buffer.h"
39#include "key.h"
40#include "hostfile.h"
41#include "auth.h"
42#include "log.h"
43#include "channels.h"
44#include "session.h"
45#include "misc.h"
46
47#include "ssh-gss.h"
48
49static ssh_gssapi_client gssapi_client =
50 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
51 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
52
53ssh_gssapi_mech gssapi_null_mech =
54 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
55
56#ifdef KRB5
57extern ssh_gssapi_mech gssapi_kerberos_mech;
58#endif
59
60ssh_gssapi_mech* supported_mechs[]= {
61#ifdef KRB5
62 &gssapi_kerberos_mech,
63#endif
64 &gssapi_null_mech,
65};
66
67/* Unprivileged */
68void
69ssh_gssapi_supported_oids(gss_OID_set *oidset)
70{
71 int i = 0;
72 OM_uint32 min_status;
73 int present;
74 gss_OID_set supported;
75
76 gss_create_empty_oid_set(&min_status, oidset);
77 gss_indicate_mechs(&min_status, &supported);
78
79 while (supported_mechs[i]->name != NULL) {
80 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
81 &supported_mechs[i]->oid, supported, &present)))
82 present = 0;
83 if (present)
84 gss_add_oid_set_member(&min_status,
85 &supported_mechs[i]->oid, oidset);
86 i++;
87 }
88
89 gss_release_oid_set(&min_status, &supported);
90}
91
92
93/* Wrapper around accept_sec_context
94 * Requires that the context contains:
95 * oid
96 * credentials (from ssh_gssapi_acquire_cred)
97 */
98/* Privileged */
99OM_uint32
100ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
101 gss_buffer_desc *send_tok, OM_uint32 *flags)
102{
103 OM_uint32 status;
104 gss_OID mech;
105
106 ctx->major = gss_accept_sec_context(&ctx->minor,
107 &ctx->context, ctx->creds, recv_tok,
108 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
109 send_tok, flags, NULL, &ctx->client_creds);
110
111 if (GSS_ERROR(ctx->major))
112 ssh_gssapi_error(ctx);
113
114 if (ctx->client_creds)
115 debug("Received some client credentials");
116 else
117 debug("Got no client credentials");
118
119 status = ctx->major;
120
121 /* Now, if we're complete and we have the right flags, then
122 * we flag the user as also having been authenticated
123 */
124
125 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
126 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
127 if (ssh_gssapi_getclient(ctx, &gssapi_client))
128 fatal("Couldn't convert client name");
129 }
130
131 return (status);
132}
133
134/*
135 * This parses an exported name, extracting the mechanism specific portion
136 * to use for ACL checking. It verifies that the name belongs the mechanism
137 * originally selected.
138 */
139static OM_uint32
140ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
141{
142 u_char *tok;
143 OM_uint32 offset;
144 OM_uint32 oidl;
145
146 tok = ename->value;
147
148 /*
149 * Check that ename is long enough for all of the fixed length
150 * header, and that the initial ID bytes are correct
151 */
152
153 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
154 return GSS_S_FAILURE;
155
156 /*
157 * Extract the OID, and check it. Here GSSAPI breaks with tradition
158 * and does use the OID type and length bytes. To confuse things
159 * there are two lengths - the first including these, and the
160 * second without.
161 */
162
163 oidl = get_u16(tok+2); /* length including next two bytes */
164 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
165
166 /*
167 * Check the BER encoding for correct type and length, that the
168 * string is long enough and that the OID matches that in our context
169 */
170 if (tok[4] != 0x06 || tok[5] != oidl ||
171 ename->length < oidl+6 ||
172 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
173 return GSS_S_FAILURE;
174
175 offset = oidl+6;
176
177 if (ename->length < offset+4)
178 return GSS_S_FAILURE;
179
180 name->length = get_u32(tok+offset);
181 offset += 4;
182
183 if (ename->length < offset+name->length)
184 return GSS_S_FAILURE;
185
186 name->value = xmalloc(name->length+1);
187 memcpy(name->value, tok+offset, name->length);
188 ((char *)name->value)[name->length] = 0;
189
190 return GSS_S_COMPLETE;
191}
192
193/* Extract the client details from a given context. This can only reliably
194 * be called once for a context */
195
196/* Privileged (called from accept_secure_ctx) */
197OM_uint32
198ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
199{
200 int i = 0;
201
202 gss_buffer_desc ename;
203
204 client->mech = NULL;
205
206 while (supported_mechs[i]->name != NULL) {
207 if (supported_mechs[i]->oid.length == ctx->oid->length &&
208 (memcmp(supported_mechs[i]->oid.elements,
209 ctx->oid->elements, ctx->oid->length) == 0))
210 client->mech = supported_mechs[i];
211 i++;
212 }
213
214 if (client->mech == NULL)
215 return GSS_S_FAILURE;
216
217 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
218 &client->displayname, NULL))) {
219 ssh_gssapi_error(ctx);
220 return (ctx->major);
221 }
222
223 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
224 &ename))) {
225 ssh_gssapi_error(ctx);
226 return (ctx->major);
227 }
228
229 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
230 &client->exportedname))) {
231 return (ctx->major);
232 }
233
234 /* We can't copy this structure, so we just move the pointer to it */
235 client->creds = ctx->client_creds;
236 ctx->client_creds = GSS_C_NO_CREDENTIAL;
237 return (ctx->major);
238}
239
240/* As user - called on fatal/exit */
241void
242ssh_gssapi_cleanup_creds(void)
243{
244 if (gssapi_client.store.filename != NULL) {
245 /* Unlink probably isn't sufficient */
246 debug("removing gssapi cred file\"%s\"",
247 gssapi_client.store.filename);
248 unlink(gssapi_client.store.filename);
249 }
250}
251
252/* As user */
253void
254ssh_gssapi_storecreds(void)
255{
256 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
257 (*gssapi_client.mech->storecreds)(&gssapi_client);
258 } else
259 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
260}
261
262/* This allows GSSAPI methods to do things to the childs environment based
263 * on the passed authentication process and credentials.
264 */
265/* As user */
266void
267ssh_gssapi_do_child(char ***envp, u_int *envsizep)
268{
269
270 if (gssapi_client.store.envvar != NULL &&
271 gssapi_client.store.envval != NULL) {
272 debug("Setting %s to %s", gssapi_client.store.envvar,
273 gssapi_client.store.envval);
274 child_set_env(envp, envsizep, gssapi_client.store.envvar,
275 gssapi_client.store.envval);
276 }
277}
278
279/* Privileged */
280int
281ssh_gssapi_userok(char *user)
282{
283 OM_uint32 lmin;
284
285 if (gssapi_client.exportedname.length == 0 ||
286 gssapi_client.exportedname.value == NULL) {
287 debug("No suitable client data");
288 return 0;
289 }
290 if (gssapi_client.mech && gssapi_client.mech->userok)
291 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
292 return 1;
293 else {
294 /* Destroy delegated credentials if userok fails */
295 gss_release_buffer(&lmin, &gssapi_client.displayname);
296 gss_release_buffer(&lmin, &gssapi_client.exportedname);
297 gss_release_cred(&lmin, &gssapi_client.creds);
298 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
299 return 0;
300 }
301 else
302 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
303 return (0);
304}
305
306/* Privileged */
307OM_uint32
308ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
309{
310 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
311 gssbuf, gssmic, NULL);
312
313 return (ctx->major);
314}
315
316#endif