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aff51935 | 1 | /* $OpenBSD: gss-genr.c,v 1.3 2003/11/21 11:57:03 djm Exp $ */ |
7364bd04 | 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 "xmalloc.h" | |
32 | #include "bufaux.h" | |
33 | #include "compat.h" | |
34 | #include "log.h" | |
35 | #include "monitor_wrap.h" | |
0789992b | 36 | #include "ssh2.h" |
7364bd04 | 37 | |
38 | #include "ssh-gss.h" | |
39 | ||
0789992b | 40 | extern u_char *session_id2; |
41 | extern u_int session_id2_len; | |
7364bd04 | 42 | |
43 | /* Check that the OID in a data stream matches that in the context */ | |
44 | int | |
45 | ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len) | |
46 | { | |
47 | return (ctx != NULL && ctx->oid != GSS_C_NO_OID && | |
48 | ctx->oid->length == len && | |
49 | memcmp(ctx->oid->elements, data, len) == 0); | |
50 | } | |
51 | ||
52 | /* Set the contexts OID from a data stream */ | |
53 | void | |
54 | ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len) | |
55 | { | |
56 | if (ctx->oid != GSS_C_NO_OID) { | |
57 | xfree(ctx->oid->elements); | |
58 | xfree(ctx->oid); | |
59 | } | |
60 | ctx->oid = xmalloc(sizeof(gss_OID_desc)); | |
61 | ctx->oid->length = len; | |
62 | ctx->oid->elements = xmalloc(len); | |
63 | memcpy(ctx->oid->elements, data, len); | |
64 | } | |
65 | ||
66 | /* Set the contexts OID */ | |
67 | void | |
68 | ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid) | |
69 | { | |
70 | ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length); | |
71 | } | |
72 | ||
73 | /* All this effort to report an error ... */ | |
74 | void | |
75 | ssh_gssapi_error(Gssctxt *ctxt) | |
76 | { | |
77 | debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL)); | |
78 | } | |
79 | ||
80 | char * | |
81 | ssh_gssapi_last_error(Gssctxt *ctxt, | |
82 | OM_uint32 *major_status, OM_uint32 *minor_status) | |
83 | { | |
84 | OM_uint32 lmin; | |
85 | gss_buffer_desc msg = GSS_C_EMPTY_BUFFER; | |
86 | OM_uint32 ctx; | |
87 | Buffer b; | |
88 | char *ret; | |
89 | ||
90 | buffer_init(&b); | |
91 | ||
92 | if (major_status != NULL) | |
93 | *major_status = ctxt->major; | |
94 | if (minor_status != NULL) | |
95 | *minor_status = ctxt->minor; | |
96 | ||
97 | ctx = 0; | |
98 | /* The GSSAPI error */ | |
99 | do { | |
100 | gss_display_status(&lmin, ctxt->major, | |
101 | GSS_C_GSS_CODE, GSS_C_NULL_OID, &ctx, &msg); | |
102 | ||
103 | buffer_append(&b, msg.value, msg.length); | |
104 | buffer_put_char(&b, '\n'); | |
105 | ||
106 | gss_release_buffer(&lmin, &msg); | |
107 | } while (ctx != 0); | |
108 | ||
109 | /* The mechanism specific error */ | |
110 | do { | |
111 | gss_display_status(&lmin, ctxt->minor, | |
112 | GSS_C_MECH_CODE, GSS_C_NULL_OID, &ctx, &msg); | |
113 | ||
114 | buffer_append(&b, msg.value, msg.length); | |
115 | buffer_put_char(&b, '\n'); | |
116 | ||
117 | gss_release_buffer(&lmin, &msg); | |
118 | } while (ctx != 0); | |
119 | ||
120 | buffer_put_char(&b, '\0'); | |
121 | ret = xmalloc(buffer_len(&b)); | |
122 | buffer_get(&b, ret, buffer_len(&b)); | |
123 | buffer_free(&b); | |
124 | return (ret); | |
125 | } | |
126 | ||
127 | /* | |
128 | * Initialise our GSSAPI context. We use this opaque structure to contain all | |
129 | * of the data which both the client and server need to persist across | |
130 | * {accept,init}_sec_context calls, so that when we do it from the userauth | |
131 | * stuff life is a little easier | |
132 | */ | |
133 | void | |
134 | ssh_gssapi_build_ctx(Gssctxt **ctx) | |
135 | { | |
136 | *ctx = xmalloc(sizeof (Gssctxt)); | |
137 | (*ctx)->major = 0; | |
138 | (*ctx)->minor = 0; | |
139 | (*ctx)->context = GSS_C_NO_CONTEXT; | |
140 | (*ctx)->name = GSS_C_NO_NAME; | |
141 | (*ctx)->oid = GSS_C_NO_OID; | |
142 | (*ctx)->creds = GSS_C_NO_CREDENTIAL; | |
143 | (*ctx)->client = GSS_C_NO_NAME; | |
144 | (*ctx)->client_creds = GSS_C_NO_CREDENTIAL; | |
145 | } | |
146 | ||
147 | /* Delete our context, providing it has been built correctly */ | |
148 | void | |
149 | ssh_gssapi_delete_ctx(Gssctxt **ctx) | |
150 | { | |
151 | OM_uint32 ms; | |
152 | ||
153 | if ((*ctx) == NULL) | |
154 | return; | |
155 | if ((*ctx)->context != GSS_C_NO_CONTEXT) | |
156 | gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER); | |
157 | if ((*ctx)->name != GSS_C_NO_NAME) | |
158 | gss_release_name(&ms, &(*ctx)->name); | |
159 | if ((*ctx)->oid != GSS_C_NO_OID) { | |
160 | xfree((*ctx)->oid->elements); | |
161 | xfree((*ctx)->oid); | |
162 | (*ctx)->oid = GSS_C_NO_OID; | |
163 | } | |
164 | if ((*ctx)->creds != GSS_C_NO_CREDENTIAL) | |
165 | gss_release_cred(&ms, &(*ctx)->creds); | |
166 | if ((*ctx)->client != GSS_C_NO_NAME) | |
167 | gss_release_name(&ms, &(*ctx)->client); | |
168 | if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL) | |
169 | gss_release_cred(&ms, &(*ctx)->client_creds); | |
170 | ||
171 | xfree(*ctx); | |
172 | *ctx = NULL; | |
173 | } | |
174 | ||
175 | /* | |
176 | * Wrapper to init_sec_context | |
177 | * Requires that the context contains: | |
178 | * oid | |
179 | * server name (from ssh_gssapi_import_name) | |
180 | */ | |
181 | OM_uint32 | |
182 | ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok, | |
183 | gss_buffer_desc* send_tok, OM_uint32 *flags) | |
184 | { | |
185 | int deleg_flag = 0; | |
186 | ||
187 | if (deleg_creds) { | |
188 | deleg_flag = GSS_C_DELEG_FLAG; | |
189 | debug("Delegating credentials"); | |
190 | } | |
191 | ||
192 | ctx->major = gss_init_sec_context(&ctx->minor, | |
193 | GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid, | |
194 | GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag, | |
195 | 0, NULL, recv_tok, NULL, send_tok, flags, NULL); | |
196 | ||
197 | if (GSS_ERROR(ctx->major)) | |
198 | ssh_gssapi_error(ctx); | |
199 | ||
200 | return (ctx->major); | |
201 | } | |
202 | ||
203 | /* Create a service name for the given host */ | |
204 | OM_uint32 | |
205 | ssh_gssapi_import_name(Gssctxt *ctx, const char *host) | |
206 | { | |
207 | gss_buffer_desc gssbuf; | |
208 | ||
209 | gssbuf.length = sizeof("host@") + strlen(host); | |
210 | gssbuf.value = xmalloc(gssbuf.length); | |
211 | snprintf(gssbuf.value, gssbuf.length, "host@%s", host); | |
212 | ||
213 | if ((ctx->major = gss_import_name(&ctx->minor, | |
214 | &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name))) | |
215 | ssh_gssapi_error(ctx); | |
216 | ||
217 | xfree(gssbuf.value); | |
218 | return (ctx->major); | |
219 | } | |
220 | ||
221 | /* Acquire credentials for a server running on the current host. | |
222 | * Requires that the context structure contains a valid OID | |
223 | */ | |
224 | ||
225 | /* Returns a GSSAPI error code */ | |
226 | OM_uint32 | |
227 | ssh_gssapi_acquire_cred(Gssctxt *ctx) | |
228 | { | |
229 | OM_uint32 status; | |
230 | char lname[MAXHOSTNAMELEN]; | |
231 | gss_OID_set oidset; | |
232 | ||
233 | gss_create_empty_oid_set(&status, &oidset); | |
234 | gss_add_oid_set_member(&status, ctx->oid, &oidset); | |
235 | ||
236 | if (gethostname(lname, MAXHOSTNAMELEN)) | |
237 | return (-1); | |
238 | ||
239 | if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) | |
240 | return (ctx->major); | |
241 | ||
242 | if ((ctx->major = gss_acquire_cred(&ctx->minor, | |
243 | ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL))) | |
244 | ssh_gssapi_error(ctx); | |
245 | ||
246 | gss_release_oid_set(&status, &oidset); | |
247 | return (ctx->major); | |
248 | } | |
249 | ||
0789992b | 250 | OM_uint32 |
251 | ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash) | |
252 | { | |
253 | if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context, | |
254 | GSS_C_QOP_DEFAULT, buffer, hash))) | |
255 | ssh_gssapi_error(ctx); | |
256 | ||
257 | return (ctx->major); | |
258 | } | |
259 | ||
260 | void | |
aff51935 | 261 | ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service, |
262 | const char *context) | |
0789992b | 263 | { |
264 | buffer_init(b); | |
265 | buffer_put_string(b, session_id2, session_id2_len); | |
266 | buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST); | |
267 | buffer_put_cstring(b, user); | |
268 | buffer_put_cstring(b, service); | |
269 | buffer_put_cstring(b, context); | |
270 | } | |
271 | ||
7364bd04 | 272 | OM_uint32 |
273 | ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) { | |
274 | if (*ctx) | |
275 | ssh_gssapi_delete_ctx(ctx); | |
276 | ssh_gssapi_build_ctx(ctx); | |
277 | ssh_gssapi_set_oid(*ctx, oid); | |
278 | return (ssh_gssapi_acquire_cred(*ctx)); | |
279 | } | |
280 | ||
281 | #endif /* GSSAPI */ |