1 /* $OpenBSD: gss-serv.c,v 1.21 2007/06/12 08:20:00 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.
31 #include <sys/types.h>
32 #include <sys/param.h>
50 static ssh_gssapi_client gssapi_client
=
51 { GSS_C_EMPTY_BUFFER
, GSS_C_EMPTY_BUFFER
,
52 GSS_C_NO_CREDENTIAL
, NULL
, {NULL
, NULL
, NULL
}};
54 ssh_gssapi_mech gssapi_null_mech
=
55 { NULL
, NULL
, {0, NULL
}, NULL
, NULL
, NULL
, NULL
};
58 extern ssh_gssapi_mech gssapi_kerberos_mech
;
61 ssh_gssapi_mech
* supported_mechs
[]= {
63 &gssapi_kerberos_mech
,
70 * Acquire credentials for a server running on the current host.
71 * Requires that the context structure contains a valid OID
74 /* Returns a GSSAPI error code */
75 /* Privileged (called from ssh_gssapi_server_ctx) */
77 ssh_gssapi_acquire_cred(Gssctxt
*ctx
)
80 char lname
[MAXHOSTNAMELEN
];
83 gss_create_empty_oid_set(&status
, &oidset
);
84 gss_add_oid_set_member(&status
, ctx
->oid
, &oidset
);
86 if (gethostname(lname
, MAXHOSTNAMELEN
)) {
87 gss_release_oid_set(&status
, &oidset
);
91 if (GSS_ERROR(ssh_gssapi_import_name(ctx
, lname
))) {
92 gss_release_oid_set(&status
, &oidset
);
96 if ((ctx
->major
= gss_acquire_cred(&ctx
->minor
,
97 ctx
->name
, 0, oidset
, GSS_C_ACCEPT
, &ctx
->creds
, NULL
, NULL
)))
98 ssh_gssapi_error(ctx
);
100 gss_release_oid_set(&status
, &oidset
);
106 ssh_gssapi_server_ctx(Gssctxt
**ctx
, gss_OID oid
)
109 ssh_gssapi_delete_ctx(ctx
);
110 ssh_gssapi_build_ctx(ctx
);
111 ssh_gssapi_set_oid(*ctx
, oid
);
112 return (ssh_gssapi_acquire_cred(*ctx
));
117 ssh_gssapi_supported_oids(gss_OID_set
*oidset
)
120 OM_uint32 min_status
;
122 gss_OID_set supported
;
124 gss_create_empty_oid_set(&min_status
, oidset
);
125 gss_indicate_mechs(&min_status
, &supported
);
127 while (supported_mechs
[i
]->name
!= NULL
) {
128 if (GSS_ERROR(gss_test_oid_set_member(&min_status
,
129 &supported_mechs
[i
]->oid
, supported
, &present
)))
132 gss_add_oid_set_member(&min_status
,
133 &supported_mechs
[i
]->oid
, oidset
);
137 gss_release_oid_set(&min_status
, &supported
);
141 /* Wrapper around accept_sec_context
142 * Requires that the context contains:
144 * credentials (from ssh_gssapi_acquire_cred)
148 ssh_gssapi_accept_ctx(Gssctxt
*ctx
, gss_buffer_desc
*recv_tok
,
149 gss_buffer_desc
*send_tok
, OM_uint32
*flags
)
154 ctx
->major
= gss_accept_sec_context(&ctx
->minor
,
155 &ctx
->context
, ctx
->creds
, recv_tok
,
156 GSS_C_NO_CHANNEL_BINDINGS
, &ctx
->client
, &mech
,
157 send_tok
, flags
, NULL
, &ctx
->client_creds
);
159 if (GSS_ERROR(ctx
->major
))
160 ssh_gssapi_error(ctx
);
162 if (ctx
->client_creds
)
163 debug("Received some client credentials");
165 debug("Got no client credentials");
169 /* Now, if we're complete and we have the right flags, then
170 * we flag the user as also having been authenticated
173 if (((flags
== NULL
) || ((*flags
& GSS_C_MUTUAL_FLAG
) &&
174 (*flags
& GSS_C_INTEG_FLAG
))) && (ctx
->major
== GSS_S_COMPLETE
)) {
175 if (ssh_gssapi_getclient(ctx
, &gssapi_client
))
176 fatal("Couldn't convert client name");
183 * This parses an exported name, extracting the mechanism specific portion
184 * to use for ACL checking. It verifies that the name belongs the mechanism
185 * originally selected.
188 ssh_gssapi_parse_ename(Gssctxt
*ctx
, gss_buffer_t ename
, gss_buffer_t name
)
197 * Check that ename is long enough for all of the fixed length
198 * header, and that the initial ID bytes are correct
201 if (ename
->length
< 6 || memcmp(tok
, "\x04\x01", 2) != 0)
202 return GSS_S_FAILURE
;
205 * Extract the OID, and check it. Here GSSAPI breaks with tradition
206 * and does use the OID type and length bytes. To confuse things
207 * there are two lengths - the first including these, and the
211 oidl
= get_u16(tok
+2); /* length including next two bytes */
212 oidl
= oidl
-2; /* turn it into the _real_ length of the variable OID */
215 * Check the BER encoding for correct type and length, that the
216 * string is long enough and that the OID matches that in our context
218 if (tok
[4] != 0x06 || tok
[5] != oidl
||
219 ename
->length
< oidl
+6 ||
220 !ssh_gssapi_check_oid(ctx
, tok
+6, oidl
))
221 return GSS_S_FAILURE
;
225 if (ename
->length
< offset
+4)
226 return GSS_S_FAILURE
;
228 name
->length
= get_u32(tok
+offset
);
231 if (ename
->length
< offset
+name
->length
)
232 return GSS_S_FAILURE
;
234 name
->value
= xmalloc(name
->length
+1);
235 memcpy(name
->value
, tok
+offset
, name
->length
);
236 ((char *)name
->value
)[name
->length
] = 0;
238 return GSS_S_COMPLETE
;
241 /* Extract the client details from a given context. This can only reliably
242 * be called once for a context */
244 /* Privileged (called from accept_secure_ctx) */
246 ssh_gssapi_getclient(Gssctxt
*ctx
, ssh_gssapi_client
*client
)
250 gss_buffer_desc ename
;
254 while (supported_mechs
[i
]->name
!= NULL
) {
255 if (supported_mechs
[i
]->oid
.length
== ctx
->oid
->length
&&
256 (memcmp(supported_mechs
[i
]->oid
.elements
,
257 ctx
->oid
->elements
, ctx
->oid
->length
) == 0))
258 client
->mech
= supported_mechs
[i
];
262 if (client
->mech
== NULL
)
263 return GSS_S_FAILURE
;
265 if ((ctx
->major
= gss_display_name(&ctx
->minor
, ctx
->client
,
266 &client
->displayname
, NULL
))) {
267 ssh_gssapi_error(ctx
);
271 if ((ctx
->major
= gss_export_name(&ctx
->minor
, ctx
->client
,
273 ssh_gssapi_error(ctx
);
277 if ((ctx
->major
= ssh_gssapi_parse_ename(ctx
,&ename
,
278 &client
->exportedname
))) {
282 /* We can't copy this structure, so we just move the pointer to it */
283 client
->creds
= ctx
->client_creds
;
284 ctx
->client_creds
= GSS_C_NO_CREDENTIAL
;
288 /* As user - called on fatal/exit */
290 ssh_gssapi_cleanup_creds(void)
292 if (gssapi_client
.store
.filename
!= NULL
) {
293 /* Unlink probably isn't sufficient */
294 debug("removing gssapi cred file\"%s\"",
295 gssapi_client
.store
.filename
);
296 unlink(gssapi_client
.store
.filename
);
302 ssh_gssapi_storecreds(void)
304 if (gssapi_client
.mech
&& gssapi_client
.mech
->storecreds
) {
305 (*gssapi_client
.mech
->storecreds
)(&gssapi_client
);
307 debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
310 /* This allows GSSAPI methods to do things to the childs environment based
311 * on the passed authentication process and credentials.
315 ssh_gssapi_do_child(char ***envp
, u_int
*envsizep
)
318 if (gssapi_client
.store
.envvar
!= NULL
&&
319 gssapi_client
.store
.envval
!= NULL
) {
320 debug("Setting %s to %s", gssapi_client
.store
.envvar
,
321 gssapi_client
.store
.envval
);
322 child_set_env(envp
, envsizep
, gssapi_client
.store
.envvar
,
323 gssapi_client
.store
.envval
);
329 ssh_gssapi_userok(char *user
)
333 if (gssapi_client
.exportedname
.length
== 0 ||
334 gssapi_client
.exportedname
.value
== NULL
) {
335 debug("No suitable client data");
338 if (gssapi_client
.mech
&& gssapi_client
.mech
->userok
)
339 if ((*gssapi_client
.mech
->userok
)(&gssapi_client
, user
))
342 /* Destroy delegated credentials if userok fails */
343 gss_release_buffer(&lmin
, &gssapi_client
.displayname
);
344 gss_release_buffer(&lmin
, &gssapi_client
.exportedname
);
345 gss_release_cred(&lmin
, &gssapi_client
.creds
);
346 memset(&gssapi_client
, 0, sizeof(ssh_gssapi_client
));
350 debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
356 ssh_gssapi_checkmic(Gssctxt
*ctx
, gss_buffer_t gssbuf
, gss_buffer_t gssmic
)
358 ctx
->major
= gss_verify_mic(&ctx
->minor
, ctx
->context
,
359 gssbuf
, gssmic
, NULL
);