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00146caa | 1 | /* $OpenBSD: gss-genr.c,v 1.11 2006/07/22 20:48:23 stevesk 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 | ||
00146caa | 31 | #include <string.h> |
32 | ||
7364bd04 | 33 | #include "xmalloc.h" |
34 | #include "bufaux.h" | |
7364bd04 | 35 | #include "log.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 | { | |
0926fd19 | 77 | char *s; |
78 | ||
79 | s = ssh_gssapi_last_error(ctxt, NULL, NULL); | |
80 | debug("%s", s); | |
81 | xfree(s); | |
7364bd04 | 82 | } |
83 | ||
84 | char * | |
4e2e5cfd | 85 | ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status, |
86 | OM_uint32 *minor_status) | |
7364bd04 | 87 | { |
88 | OM_uint32 lmin; | |
89 | gss_buffer_desc msg = GSS_C_EMPTY_BUFFER; | |
90 | OM_uint32 ctx; | |
91 | Buffer b; | |
92 | char *ret; | |
93 | ||
94 | buffer_init(&b); | |
95 | ||
96 | if (major_status != NULL) | |
97 | *major_status = ctxt->major; | |
98 | if (minor_status != NULL) | |
99 | *minor_status = ctxt->minor; | |
100 | ||
101 | ctx = 0; | |
102 | /* The GSSAPI error */ | |
103 | do { | |
104 | gss_display_status(&lmin, ctxt->major, | |
105 | GSS_C_GSS_CODE, GSS_C_NULL_OID, &ctx, &msg); | |
106 | ||
107 | buffer_append(&b, msg.value, msg.length); | |
108 | buffer_put_char(&b, '\n'); | |
109 | ||
110 | gss_release_buffer(&lmin, &msg); | |
111 | } while (ctx != 0); | |
112 | ||
113 | /* The mechanism specific error */ | |
114 | do { | |
115 | gss_display_status(&lmin, ctxt->minor, | |
116 | GSS_C_MECH_CODE, GSS_C_NULL_OID, &ctx, &msg); | |
117 | ||
118 | buffer_append(&b, msg.value, msg.length); | |
119 | buffer_put_char(&b, '\n'); | |
120 | ||
121 | gss_release_buffer(&lmin, &msg); | |
122 | } while (ctx != 0); | |
123 | ||
124 | buffer_put_char(&b, '\0'); | |
125 | ret = xmalloc(buffer_len(&b)); | |
126 | buffer_get(&b, ret, buffer_len(&b)); | |
127 | buffer_free(&b); | |
128 | return (ret); | |
129 | } | |
130 | ||
131 | /* | |
132 | * Initialise our GSSAPI context. We use this opaque structure to contain all | |
133 | * of the data which both the client and server need to persist across | |
134 | * {accept,init}_sec_context calls, so that when we do it from the userauth | |
135 | * stuff life is a little easier | |
136 | */ | |
137 | void | |
138 | ssh_gssapi_build_ctx(Gssctxt **ctx) | |
139 | { | |
52e3daed | 140 | *ctx = xcalloc(1, sizeof (Gssctxt)); |
7364bd04 | 141 | (*ctx)->context = GSS_C_NO_CONTEXT; |
142 | (*ctx)->name = GSS_C_NO_NAME; | |
143 | (*ctx)->oid = GSS_C_NO_OID; | |
144 | (*ctx)->creds = GSS_C_NO_CREDENTIAL; | |
145 | (*ctx)->client = GSS_C_NO_NAME; | |
146 | (*ctx)->client_creds = GSS_C_NO_CREDENTIAL; | |
147 | } | |
148 | ||
149 | /* Delete our context, providing it has been built correctly */ | |
150 | void | |
151 | ssh_gssapi_delete_ctx(Gssctxt **ctx) | |
152 | { | |
153 | OM_uint32 ms; | |
154 | ||
155 | if ((*ctx) == NULL) | |
156 | return; | |
157 | if ((*ctx)->context != GSS_C_NO_CONTEXT) | |
158 | gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER); | |
159 | if ((*ctx)->name != GSS_C_NO_NAME) | |
160 | gss_release_name(&ms, &(*ctx)->name); | |
161 | if ((*ctx)->oid != GSS_C_NO_OID) { | |
162 | xfree((*ctx)->oid->elements); | |
163 | xfree((*ctx)->oid); | |
164 | (*ctx)->oid = GSS_C_NO_OID; | |
165 | } | |
166 | if ((*ctx)->creds != GSS_C_NO_CREDENTIAL) | |
167 | gss_release_cred(&ms, &(*ctx)->creds); | |
168 | if ((*ctx)->client != GSS_C_NO_NAME) | |
169 | gss_release_name(&ms, &(*ctx)->client); | |
170 | if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL) | |
171 | gss_release_cred(&ms, &(*ctx)->client_creds); | |
172 | ||
173 | xfree(*ctx); | |
174 | *ctx = NULL; | |
175 | } | |
176 | ||
177 | /* | |
178 | * Wrapper to init_sec_context | |
179 | * Requires that the context contains: | |
180 | * oid | |
181 | * server name (from ssh_gssapi_import_name) | |
182 | */ | |
183 | OM_uint32 | |
184 | ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok, | |
185 | gss_buffer_desc* send_tok, OM_uint32 *flags) | |
186 | { | |
187 | int deleg_flag = 0; | |
188 | ||
189 | if (deleg_creds) { | |
190 | deleg_flag = GSS_C_DELEG_FLAG; | |
191 | debug("Delegating credentials"); | |
192 | } | |
193 | ||
194 | ctx->major = gss_init_sec_context(&ctx->minor, | |
195 | GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid, | |
196 | GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag, | |
197 | 0, NULL, recv_tok, NULL, send_tok, flags, NULL); | |
198 | ||
199 | if (GSS_ERROR(ctx->major)) | |
200 | ssh_gssapi_error(ctx); | |
201 | ||
202 | return (ctx->major); | |
203 | } | |
204 | ||
205 | /* Create a service name for the given host */ | |
206 | OM_uint32 | |
207 | ssh_gssapi_import_name(Gssctxt *ctx, const char *host) | |
208 | { | |
209 | gss_buffer_desc gssbuf; | |
9c3c8eb1 | 210 | char *val; |
7364bd04 | 211 | |
9c3c8eb1 | 212 | xasprintf(&val, "host@%s", host); |
213 | gssbuf.value = val; | |
214 | gssbuf.length = strlen(gssbuf.value); | |
7364bd04 | 215 | |
216 | if ((ctx->major = gss_import_name(&ctx->minor, | |
217 | &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name))) | |
218 | ssh_gssapi_error(ctx); | |
219 | ||
220 | xfree(gssbuf.value); | |
221 | return (ctx->major); | |
222 | } | |
223 | ||
224 | /* Acquire credentials for a server running on the current host. | |
225 | * Requires that the context structure contains a valid OID | |
226 | */ | |
227 | ||
228 | /* Returns a GSSAPI error code */ | |
229 | OM_uint32 | |
230 | ssh_gssapi_acquire_cred(Gssctxt *ctx) | |
231 | { | |
232 | OM_uint32 status; | |
233 | char lname[MAXHOSTNAMELEN]; | |
234 | gss_OID_set oidset; | |
235 | ||
236 | gss_create_empty_oid_set(&status, &oidset); | |
237 | gss_add_oid_set_member(&status, ctx->oid, &oidset); | |
238 | ||
0926fd19 | 239 | if (gethostname(lname, MAXHOSTNAMELEN)) { |
240 | gss_release_oid_set(&status, &oidset); | |
7364bd04 | 241 | return (-1); |
0926fd19 | 242 | } |
7364bd04 | 243 | |
0926fd19 | 244 | if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) { |
245 | gss_release_oid_set(&status, &oidset); | |
7364bd04 | 246 | return (ctx->major); |
0926fd19 | 247 | } |
7364bd04 | 248 | |
249 | if ((ctx->major = gss_acquire_cred(&ctx->minor, | |
250 | ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL))) | |
251 | ssh_gssapi_error(ctx); | |
252 | ||
253 | gss_release_oid_set(&status, &oidset); | |
254 | return (ctx->major); | |
255 | } | |
256 | ||
0789992b | 257 | OM_uint32 |
258 | ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash) | |
259 | { | |
260 | if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context, | |
261 | GSS_C_QOP_DEFAULT, buffer, hash))) | |
262 | ssh_gssapi_error(ctx); | |
b6453d99 | 263 | |
0789992b | 264 | return (ctx->major); |
265 | } | |
266 | ||
267 | void | |
aff51935 | 268 | ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service, |
269 | const char *context) | |
b6453d99 | 270 | { |
0789992b | 271 | buffer_init(b); |
272 | buffer_put_string(b, session_id2, session_id2_len); | |
273 | buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST); | |
274 | buffer_put_cstring(b, user); | |
275 | buffer_put_cstring(b, service); | |
276 | buffer_put_cstring(b, context); | |
277 | } | |
278 | ||
7364bd04 | 279 | OM_uint32 |
8442cc66 | 280 | ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) |
281 | { | |
7364bd04 | 282 | if (*ctx) |
283 | ssh_gssapi_delete_ctx(ctx); | |
284 | ssh_gssapi_build_ctx(ctx); | |
285 | ssh_gssapi_set_oid(*ctx, oid); | |
286 | return (ssh_gssapi_acquire_cred(*ctx)); | |
287 | } | |
288 | ||
289 | #endif /* GSSAPI */ |