1 /* $OpenBSD: gss-serv.c,v 1.19 2006/07/22 20:48:23 stevesk 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.
43 static ssh_gssapi_client gssapi_client =
44 { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
45 GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
47 ssh_gssapi_mech gssapi_null_mech =
48 { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
51 extern ssh_gssapi_mech gssapi_kerberos_mech;
54 ssh_gssapi_mech* supported_mechs[]= {
56 &gssapi_kerberos_mech,
63 ssh_gssapi_supported_oids(gss_OID_set *oidset)
68 gss_OID_set supported;
70 gss_create_empty_oid_set(&min_status, oidset);
71 gss_indicate_mechs(&min_status, &supported);
73 while (supported_mechs[i]->name != NULL) {
74 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
75 &supported_mechs[i]->oid, supported, &present)))
78 gss_add_oid_set_member(&min_status,
79 &supported_mechs[i]->oid, oidset);
83 gss_release_oid_set(&min_status, &supported);
87 /* Wrapper around accept_sec_context
88 * Requires that the context contains:
90 * credentials (from ssh_gssapi_acquire_cred)
94 ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
95 gss_buffer_desc *send_tok, OM_uint32 *flags)
100 ctx->major = gss_accept_sec_context(&ctx->minor,
101 &ctx->context, ctx->creds, recv_tok,
102 GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
103 send_tok, flags, NULL, &ctx->client_creds);
105 if (GSS_ERROR(ctx->major))
106 ssh_gssapi_error(ctx);
108 if (ctx->client_creds)
109 debug("Received some client credentials");
111 debug("Got no client credentials");
115 /* Now, if we're complete and we have the right flags, then
116 * we flag the user as also having been authenticated
119 if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
120 (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
121 if (ssh_gssapi_getclient(ctx, &gssapi_client))
122 fatal("Couldn't convert client name");
129 * This parses an exported name, extracting the mechanism specific portion
130 * to use for ACL checking. It verifies that the name belongs the mechanism
131 * originally selected.
134 ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
143 * Check that ename is long enough for all of the fixed length
144 * header, and that the initial ID bytes are correct
147 if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
148 return GSS_S_FAILURE;
151 * Extract the OID, and check it. Here GSSAPI breaks with tradition
152 * and does use the OID type and length bytes. To confuse things
153 * there are two lengths - the first including these, and the
157 oidl = get_u16(tok+2); /* length including next two bytes */
158 oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
161 * Check the BER encoding for correct type and length, that the
162 * string is long enough and that the OID matches that in our context
164 if (tok[4] != 0x06 || tok[5] != oidl ||
165 ename->length < oidl+6 ||
166 !ssh_gssapi_check_oid(ctx, tok+6, oidl))
167 return GSS_S_FAILURE;
171 if (ename->length < offset+4)
172 return GSS_S_FAILURE;
174 name->length = get_u32(tok+offset);
177 if (ename->length < offset+name->length)
178 return GSS_S_FAILURE;
180 name->value = xmalloc(name->length+1);
181 memcpy(name->value, tok+offset, name->length);
182 ((char *)name->value)[name->length] = 0;
184 return GSS_S_COMPLETE;
187 /* Extract the client details from a given context. This can only reliably
188 * be called once for a context */
190 /* Privileged (called from accept_secure_ctx) */
192 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
196 gss_buffer_desc ename;
200 while (supported_mechs[i]->name != NULL) {
201 if (supported_mechs[i]->oid.length == ctx->oid->length &&
202 (memcmp(supported_mechs[i]->oid.elements,
203 ctx->oid->elements, ctx->oid->length) == 0))
204 client->mech = supported_mechs[i];
208 if (client->mech == NULL)
209 return GSS_S_FAILURE;
211 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
212 &client->displayname, NULL))) {
213 ssh_gssapi_error(ctx);
217 if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
219 ssh_gssapi_error(ctx);
223 if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
224 &client->exportedname))) {
228 /* We can't copy this structure, so we just move the pointer to it */
229 client->creds = ctx->client_creds;
230 ctx->client_creds = GSS_C_NO_CREDENTIAL;
234 /* As user - called on fatal/exit */
236 ssh_gssapi_cleanup_creds(void)
238 if (gssapi_client.store.filename != NULL) {
239 /* Unlink probably isn't sufficient */
240 debug("removing gssapi cred file\"%s\"",
241 gssapi_client.store.filename);
242 unlink(gssapi_client.store.filename);
248 ssh_gssapi_storecreds(void)
250 if (gssapi_client.mech && gssapi_client.mech->storecreds) {
251 (*gssapi_client.mech->storecreds)(&gssapi_client);
253 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
256 /* This allows GSSAPI methods to do things to the childs environment based
257 * on the passed authentication process and credentials.
261 ssh_gssapi_do_child(char ***envp, u_int *envsizep)
264 if (gssapi_client.store.envvar != NULL &&
265 gssapi_client.store.envval != NULL) {
266 debug("Setting %s to %s", gssapi_client.store.envvar,
267 gssapi_client.store.envval);
268 child_set_env(envp, envsizep, gssapi_client.store.envvar,
269 gssapi_client.store.envval);
275 ssh_gssapi_userok(char *user)
279 if (gssapi_client.exportedname.length == 0 ||
280 gssapi_client.exportedname.value == NULL) {
281 debug("No suitable client data");
284 if (gssapi_client.mech && gssapi_client.mech->userok)
285 if ((*gssapi_client.mech->userok)(&gssapi_client, user))
288 /* Destroy delegated credentials if userok fails */
289 gss_release_buffer(&lmin, &gssapi_client.displayname);
290 gss_release_buffer(&lmin, &gssapi_client.exportedname);
291 gss_release_cred(&lmin, &gssapi_client.creds);
292 memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
296 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
302 ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
304 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
305 gssbuf, gssmic, NULL);