1 /* $OpenBSD: gss-genr.c,v 1.28 2021/01/27 10:05:28 djm Exp $ */
4 * Copyright (c) 2001-2007 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>
47 /* sshbuf_get for gss_buffer_desc */
49 ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
55 if ((r = sshbuf_get_string(b, &p, &len)) != 0)
62 /* Check that the OID in a data stream matches that in the context */
64 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
66 return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
67 ctx->oid->length == len &&
68 memcmp(ctx->oid->elements, data, len) == 0);
71 /* Set the contexts OID from a data stream */
73 ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
75 if (ctx->oid != GSS_C_NO_OID) {
76 free(ctx->oid->elements);
79 ctx->oid = xcalloc(1, sizeof(gss_OID_desc));
80 ctx->oid->length = len;
81 ctx->oid->elements = xmalloc(len);
82 memcpy(ctx->oid->elements, data, len);
85 /* Set the contexts OID */
87 ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
89 ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
92 /* All this effort to report an error ... */
94 ssh_gssapi_error(Gssctxt *ctxt)
98 s = ssh_gssapi_last_error(ctxt, NULL, NULL);
104 ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
105 OM_uint32 *minor_status)
108 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
114 if ((b = sshbuf_new()) == NULL)
115 fatal_f("sshbuf_new failed");
117 if (major_status != NULL)
118 *major_status = ctxt->major;
119 if (minor_status != NULL)
120 *minor_status = ctxt->minor;
123 /* The GSSAPI error */
125 gss_display_status(&lmin, ctxt->major,
126 GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
128 if ((r = sshbuf_put(b, msg.value, msg.length)) != 0 ||
129 (r = sshbuf_put_u8(b, '\n')) != 0)
130 fatal_fr(r, "assemble GSS_CODE");
132 gss_release_buffer(&lmin, &msg);
135 /* The mechanism specific error */
137 gss_display_status(&lmin, ctxt->minor,
138 GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
140 if ((r = sshbuf_put(b, msg.value, msg.length)) != 0 ||
141 (r = sshbuf_put_u8(b, '\n')) != 0)
142 fatal_fr(r, "assemble MECH_CODE");
144 gss_release_buffer(&lmin, &msg);
147 if ((r = sshbuf_put_u8(b, '\n')) != 0)
148 fatal_fr(r, "assemble newline");
149 ret = xstrdup((const char *)sshbuf_ptr(b));
155 * Initialise our GSSAPI context. We use this opaque structure to contain all
156 * of the data which both the client and server need to persist across
157 * {accept,init}_sec_context calls, so that when we do it from the userauth
158 * stuff life is a little easier
161 ssh_gssapi_build_ctx(Gssctxt **ctx)
163 *ctx = xcalloc(1, sizeof (Gssctxt));
164 (*ctx)->context = GSS_C_NO_CONTEXT;
165 (*ctx)->name = GSS_C_NO_NAME;
166 (*ctx)->oid = GSS_C_NO_OID;
167 (*ctx)->creds = GSS_C_NO_CREDENTIAL;
168 (*ctx)->client = GSS_C_NO_NAME;
169 (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
172 /* Delete our context, providing it has been built correctly */
174 ssh_gssapi_delete_ctx(Gssctxt **ctx)
180 if ((*ctx)->context != GSS_C_NO_CONTEXT)
181 gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
182 if ((*ctx)->name != GSS_C_NO_NAME)
183 gss_release_name(&ms, &(*ctx)->name);
184 if ((*ctx)->oid != GSS_C_NO_OID) {
185 free((*ctx)->oid->elements);
187 (*ctx)->oid = GSS_C_NO_OID;
189 if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
190 gss_release_cred(&ms, &(*ctx)->creds);
191 if ((*ctx)->client != GSS_C_NO_NAME)
192 gss_release_name(&ms, &(*ctx)->client);
193 if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
194 gss_release_cred(&ms, &(*ctx)->client_creds);
201 * Wrapper to init_sec_context
202 * Requires that the context contains:
204 * server name (from ssh_gssapi_import_name)
207 ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
208 gss_buffer_desc* send_tok, OM_uint32 *flags)
213 deleg_flag = GSS_C_DELEG_FLAG;
214 debug("Delegating credentials");
217 ctx->major = gss_init_sec_context(&ctx->minor,
218 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
219 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
220 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
222 if (GSS_ERROR(ctx->major))
223 ssh_gssapi_error(ctx);
228 /* Create a service name for the given host */
230 ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
232 gss_buffer_desc gssbuf;
235 xasprintf(&val, "host@%s", host);
237 gssbuf.length = strlen(gssbuf.value);
239 if ((ctx->major = gss_import_name(&ctx->minor,
240 &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
241 ssh_gssapi_error(ctx);
248 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
250 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
251 GSS_C_QOP_DEFAULT, buffer, hash)))
252 ssh_gssapi_error(ctx);
258 ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
259 const char *context, const struct sshbuf *session_id)
264 if ((r = sshbuf_put_stringb(b, session_id)) != 0 ||
265 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
266 (r = sshbuf_put_cstring(b, user)) != 0 ||
267 (r = sshbuf_put_cstring(b, service)) != 0 ||
268 (r = sshbuf_put_cstring(b, context)) != 0)
269 fatal_fr(r, "assemble buildmic");
273 ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
275 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
276 OM_uint32 major, minor;
277 gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
279 /* RFC 4462 says we MUST NOT do SPNEGO */
280 if (oid->length == spnego_oid.length &&
281 (memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
282 return 0; /* false */
284 ssh_gssapi_build_ctx(ctx);
285 ssh_gssapi_set_oid(*ctx, oid);
286 major = ssh_gssapi_import_name(*ctx, host);
287 if (!GSS_ERROR(major)) {
288 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
290 gss_release_buffer(&minor, &token);
291 if ((*ctx)->context != GSS_C_NO_CONTEXT)
292 gss_delete_sec_context(&minor, &(*ctx)->context,
296 if (GSS_ERROR(major))
297 ssh_gssapi_delete_ctx(ctx);
299 return (!GSS_ERROR(major));