1 /* $NetBSD: gss_accept_sec_context.c,v 1.2 2017/01/28 21:31:46 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2005 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: src/lib/libgssapi/gss_accept_sec_context.c,v 1.1 2005/12/29 14:40:20 dfr Exp $
29 */
30
31 #include "mech_locl.h"
32
33 static OM_uint32
parse_header(const gss_buffer_t input_token,gss_OID mech_oid)34 parse_header(const gss_buffer_t input_token, gss_OID mech_oid)
35 {
36 unsigned char *p = input_token->value;
37 size_t len = input_token->length;
38 size_t a, b;
39
40 /*
41 * Token must start with [APPLICATION 0] SEQUENCE.
42 * But if it doesn't assume it is DCE-STYLE Kerberos!
43 */
44 if (len == 0)
45 return (GSS_S_DEFECTIVE_TOKEN);
46
47 p++;
48 len--;
49
50 /*
51 * Decode the length and make sure it agrees with the
52 * token length.
53 */
54 if (len == 0)
55 return (GSS_S_DEFECTIVE_TOKEN);
56 if ((*p & 0x80) == 0) {
57 a = *p;
58 p++;
59 len--;
60 } else {
61 b = *p & 0x7f;
62 p++;
63 len--;
64 if (len < b)
65 return (GSS_S_DEFECTIVE_TOKEN);
66 a = 0;
67 while (b) {
68 a = (a << 8) | *p;
69 p++;
70 len--;
71 b--;
72 }
73 }
74 if (a != len)
75 return (GSS_S_DEFECTIVE_TOKEN);
76
77 /*
78 * Decode the OID for the mechanism. Simplify life by
79 * assuming that the OID length is less than 128 bytes.
80 */
81 if (len < 2 || *p != 0x06)
82 return (GSS_S_DEFECTIVE_TOKEN);
83 if ((p[1] & 0x80) || p[1] > (len - 2))
84 return (GSS_S_DEFECTIVE_TOKEN);
85 mech_oid->length = p[1];
86 p += 2;
87 len -= 2;
88 mech_oid->elements = p;
89
90 return GSS_S_COMPLETE;
91 }
92
93 static gss_OID_desc krb5_mechanism =
94 {9, rk_UNCONST("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02")};
95 static gss_OID_desc ntlm_mechanism =
96 {10, rk_UNCONST("\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a")};
97 static gss_OID_desc spnego_mechanism =
98 {6, rk_UNCONST("\x2b\x06\x01\x05\x05\x02")};
99
100 static OM_uint32
choose_mech(const gss_buffer_t input,gss_OID mech_oid)101 choose_mech(const gss_buffer_t input, gss_OID mech_oid)
102 {
103 OM_uint32 status;
104
105 /*
106 * First try to parse the gssapi token header and see if it's a
107 * correct header, use that in the first hand.
108 */
109
110 status = parse_header(input, mech_oid);
111 if (status == GSS_S_COMPLETE)
112 return GSS_S_COMPLETE;
113
114 /*
115 * Lets guess what mech is really is, callback function to mech ??
116 */
117
118 if (input->length > 8 &&
119 memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0)
120 {
121 *mech_oid = ntlm_mechanism;
122 return GSS_S_COMPLETE;
123 } else if (input->length != 0 &&
124 ((const char *)input->value)[0] == 0x6E)
125 {
126 /* Could be a raw AP-REQ (check for APPLICATION tag) */
127 *mech_oid = krb5_mechanism;
128 return GSS_S_COMPLETE;
129 } else if (input->length == 0) {
130 /*
131 * There is the a wierd mode of SPNEGO (in CIFS and
132 * SASL GSS-SPENGO where the first token is zero
133 * length and the acceptor returns a mech_list, lets
134 * hope that is what is happening now.
135 *
136 * http://msdn.microsoft.com/en-us/library/cc213114.aspx
137 * "NegTokenInit2 Variation for Server-Initiation"
138 */
139 *mech_oid = spnego_mechanism;
140 return GSS_S_COMPLETE;
141 }
142 return status;
143 }
144
145
146 GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_accept_sec_context(OM_uint32 * minor_status,gss_ctx_id_t * context_handle,gss_const_cred_id_t acceptor_cred_handle,const gss_buffer_t input_token,const gss_channel_bindings_t input_chan_bindings,gss_name_t * src_name,gss_OID * mech_type,gss_buffer_t output_token,OM_uint32 * ret_flags,OM_uint32 * time_rec,gss_cred_id_t * delegated_cred_handle)147 gss_accept_sec_context(OM_uint32 *minor_status,
148 gss_ctx_id_t *context_handle,
149 gss_const_cred_id_t acceptor_cred_handle,
150 const gss_buffer_t input_token,
151 const gss_channel_bindings_t input_chan_bindings,
152 gss_name_t *src_name,
153 gss_OID *mech_type,
154 gss_buffer_t output_token,
155 OM_uint32 *ret_flags,
156 OM_uint32 *time_rec,
157 gss_cred_id_t *delegated_cred_handle)
158 {
159 OM_uint32 major_status, mech_ret_flags, junk;
160 gssapi_mech_interface m;
161 struct _gss_context *ctx = (struct _gss_context *) *context_handle;
162 struct _gss_cred *cred = (struct _gss_cred *) acceptor_cred_handle;
163 struct _gss_mechanism_cred *mc;
164 gss_cred_id_t acceptor_mc, delegated_mc;
165 gss_name_t src_mn;
166 gss_OID mech_ret_type = NULL;
167
168 *minor_status = 0;
169 if (src_name)
170 *src_name = GSS_C_NO_NAME;
171 if (mech_type)
172 *mech_type = GSS_C_NO_OID;
173 if (ret_flags)
174 *ret_flags = 0;
175 if (time_rec)
176 *time_rec = 0;
177 if (delegated_cred_handle)
178 *delegated_cred_handle = GSS_C_NO_CREDENTIAL;
179 _mg_buffer_zero(output_token);
180
181
182 /*
183 * If this is the first call (*context_handle is NULL), we must
184 * parse the input token to figure out the mechanism to use.
185 */
186 if (*context_handle == GSS_C_NO_CONTEXT) {
187 gss_OID_desc mech_oid;
188
189 major_status = choose_mech(input_token, &mech_oid);
190 if (major_status != GSS_S_COMPLETE)
191 return major_status;
192
193 /*
194 * Now that we have a mechanism, we can find the
195 * implementation.
196 */
197 ctx = malloc(sizeof(struct _gss_context));
198 if (!ctx) {
199 *minor_status = ENOMEM;
200 return (GSS_S_DEFECTIVE_TOKEN);
201 }
202 memset(ctx, 0, sizeof(struct _gss_context));
203 m = ctx->gc_mech = __gss_get_mechanism(&mech_oid);
204 if (!m) {
205 free(ctx);
206 return (GSS_S_BAD_MECH);
207 }
208 *context_handle = (gss_ctx_id_t) ctx;
209 } else {
210 m = ctx->gc_mech;
211 }
212
213 if (cred) {
214 HEIM_SLIST_FOREACH(mc, &cred->gc_mc, gmc_link)
215 if (mc->gmc_mech == m)
216 break;
217 if (!mc) {
218 gss_delete_sec_context(&junk, context_handle, NULL);
219 return (GSS_S_BAD_MECH);
220 }
221 acceptor_mc = mc->gmc_cred;
222 } else {
223 acceptor_mc = GSS_C_NO_CREDENTIAL;
224 }
225 delegated_mc = GSS_C_NO_CREDENTIAL;
226
227 mech_ret_flags = 0;
228 major_status = m->gm_accept_sec_context(minor_status,
229 &ctx->gc_ctx,
230 acceptor_mc,
231 input_token,
232 input_chan_bindings,
233 &src_mn,
234 &mech_ret_type,
235 output_token,
236 &mech_ret_flags,
237 time_rec,
238 &delegated_mc);
239 if (major_status != GSS_S_COMPLETE &&
240 major_status != GSS_S_CONTINUE_NEEDED)
241 {
242 _gss_mg_error(m, major_status, *minor_status);
243 gss_delete_sec_context(&junk, context_handle, NULL);
244 return (major_status);
245 }
246
247 if (mech_type)
248 *mech_type = mech_ret_type;
249
250 if (src_name && src_mn) {
251 /*
252 * Make a new name and mark it as an MN.
253 */
254 struct _gss_name *name = _gss_make_name(m, src_mn);
255
256 if (!name) {
257 m->gm_release_name(minor_status, &src_mn);
258 gss_delete_sec_context(&junk, context_handle, NULL);
259 return (GSS_S_FAILURE);
260 }
261 *src_name = (gss_name_t) name;
262 } else if (src_mn) {
263 m->gm_release_name(minor_status, &src_mn);
264 }
265
266 if (mech_ret_flags & GSS_C_DELEG_FLAG) {
267 if (!delegated_cred_handle) {
268 m->gm_release_cred(minor_status, &delegated_mc);
269 mech_ret_flags &=
270 ~(GSS_C_DELEG_FLAG|GSS_C_DELEG_POLICY_FLAG);
271 } else if (gss_oid_equal(mech_ret_type, &m->gm_mech_oid) == 0) {
272 /*
273 * If the returned mech_type is not the same
274 * as the mech, assume its pseudo mech type
275 * and the returned type is already a
276 * mech-glue object
277 */
278 *delegated_cred_handle = delegated_mc;
279
280 } else if (delegated_mc) {
281 struct _gss_cred *dcred;
282 struct _gss_mechanism_cred *dmc;
283
284 dcred = malloc(sizeof(struct _gss_cred));
285 if (!dcred) {
286 *minor_status = ENOMEM;
287 gss_delete_sec_context(&junk, context_handle, NULL);
288 return (GSS_S_FAILURE);
289 }
290 HEIM_SLIST_INIT(&dcred->gc_mc);
291 dmc = malloc(sizeof(struct _gss_mechanism_cred));
292 if (!dmc) {
293 free(dcred);
294 *minor_status = ENOMEM;
295 gss_delete_sec_context(&junk, context_handle, NULL);
296 return (GSS_S_FAILURE);
297 }
298 dmc->gmc_mech = m;
299 dmc->gmc_mech_oid = &m->gm_mech_oid;
300 dmc->gmc_cred = delegated_mc;
301 HEIM_SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link);
302
303 *delegated_cred_handle = (gss_cred_id_t) dcred;
304 }
305 }
306
307 if (ret_flags)
308 *ret_flags = mech_ret_flags;
309 return (major_status);
310 }
311