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1 /*
2   Copyright (c) 2004-2006 The Regents of the University of Michigan.
3   All rights reserved.
4
5   Redistribution and use in source and binary forms, with or without
6   modification, are permitted provided that the following conditions
7   are met:
8
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   3. Neither the name of the University nor the names of its
15      contributors may be used to endorse or promote products derived
16      from this software without specific prior written permission.
17
18   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
19   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
20   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21   DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
25   BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #ifdef HAVE_CONFIG_H
32 #include <config.h>
33 #endif  /* HAVE_CONFIG_H */
34
35 #ifndef HAVE_LUCID_CONTEXT_SUPPORT
36 #ifdef HAVE_KRB5
37
38 #include <stdio.h>
39 #include <syslog.h>
40 #include <string.h>
41 #include <errno.h>
42 #include <gssapi/gssapi.h>
43 #include <rpc/rpc.h>
44 #include <rpc/auth_gss.h>
45 #include "gss_util.h"
46 #include "gss_oids.h"
47 #include "err_util.h"
48 #include "context.h"
49
50 #include <krb5.h>
51
52 #if (KRB5_VERSION > 131)
53 /* XXX argggg, there's gotta be a better way than just duplicating this
54  * whole struct.  Unfortunately, this is in a "private" header file,
55  * so this is our best choice at this point :-/
56  */
57
58 typedef struct _krb5_gss_ctx_id_rec {
59    unsigned int initiate : 1;   /* nonzero if initiating, zero if accepting */
60    unsigned int established : 1;
61    unsigned int big_endian : 1;
62    unsigned int have_acceptor_subkey : 1;
63    unsigned int seed_init : 1;  /* XXX tested but never actually set */
64 #ifdef CFX_EXERCISE
65    unsigned int testing_unknown_tokid : 1; /* for testing only */
66 #endif
67    OM_uint32 gss_flags;
68    unsigned char seed[16];
69    krb5_principal here;
70    krb5_principal there;
71    krb5_keyblock *subkey;
72    int signalg;
73    size_t cksum_size;
74    int sealalg;
75    krb5_keyblock *enc;
76    krb5_keyblock *seq;
77    krb5_timestamp endtime;
78    krb5_flags krb_flags;
79    /* XXX these used to be signed.  the old spec is inspecific, and
80       the new spec specifies unsigned.  I don't believe that the change
81       affects the wire encoding. */
82    uint64_t seq_send;           /* gssint_uint64 */
83    uint64_t seq_recv;           /* gssint_uint64 */
84    void *seqstate;
85    krb5_auth_context auth_context;
86    gss_OID_desc *mech_used;     /* gss_OID_desc */
87     /* Protocol spec revision
88        0 => RFC 1964 with 3DES and RC4 enhancements
89        1 => draft-ietf-krb-wg-gssapi-cfx-01
90        No others defined so far.  */
91    int proto;
92    krb5_cksumtype cksumtype;    /* for "main" subkey */
93    krb5_keyblock *acceptor_subkey; /* CFX only */
94    krb5_cksumtype acceptor_subkey_cksumtype;
95 #ifdef CFX_EXERCISE
96     gss_buffer_desc init_token;
97 #endif
98 } krb5_gss_ctx_id_rec, *krb5_gss_ctx_id_t;
99
100 #else   /* KRB5_VERSION > 131 */
101
102 typedef struct _krb5_gss_ctx_id_rec {
103         int initiate;
104         u_int32_t gss_flags;
105         int seed_init;
106         unsigned char seed[16];
107         krb5_principal here;
108         krb5_principal there;
109         krb5_keyblock *subkey;
110         int signalg;
111         int cksum_size;
112         int sealalg;
113         krb5_keyblock *enc;
114         krb5_keyblock *seq;
115         krb5_timestamp endtime;
116         krb5_flags krb_flags;
117         krb5_ui_4 seq_send;
118         krb5_ui_4 seq_recv;
119         void *seqstate;
120         int established;
121         int big_endian;
122         krb5_auth_context auth_context;
123         gss_OID_desc *mech_used;
124         int nctypes;
125         krb5_cksumtype *ctypes;
126 } krb5_gss_ctx_id_rec, *krb5_gss_ctx_id_t;
127
128 #endif /* KRB5_VERSION */
129
130
131 static int
132 write_keyblock(char **p, char *end, struct _krb5_keyblock *arg)
133 {
134         gss_buffer_desc tmp;
135
136         if (WRITE_BYTES(p, end, arg->enctype)) return -1;
137         tmp.length = arg->length;
138         tmp.value = arg->contents;
139         if (write_buffer(p, end, &tmp)) return -1;
140         return 0;
141 }
142
143 /*
144  * We really shouldn't know about glue-layer context structure, but
145  * we need to get at the real krb5 context pointer.  This should be
146  * removed as soon as we say there is no support for MIT Kerberos
147  * prior to 1.4 -- which gives us "legal" access to the context info.
148  */
149 typedef struct gss_union_ctx_id_t {
150         gss_OID         mech_type;
151         gss_ctx_id_t    internal_ctx_id;
152 } gss_union_ctx_id_desc, *gss_union_ctx_id_t;
153
154 int
155 serialize_krb5_ctx(gss_ctx_id_t ctx, gss_buffer_desc *buf, int32_t *endtime)
156 {
157         krb5_gss_ctx_id_t kctx = ((gss_union_ctx_id_t)ctx)->internal_ctx_id;
158         char *p, *end;
159         static int constant_zero = 0;
160         static int constant_one = 1;
161         static int constant_two = 2;
162         uint32_t word_seq_send;
163         u_int64_t seq_send_64bit;
164         uint32_t v2_flags = 0;
165
166         if (!(buf->value = calloc(1, MAX_CTX_LEN)))
167                 goto out_err;
168         p = buf->value;
169         end = buf->value + MAX_CTX_LEN;
170
171         switch (kctx->enc->enctype) {
172         case ENCTYPE_DES_CBC_CRC:
173         case ENCTYPE_DES_CBC_MD4:
174         case ENCTYPE_DES_CBC_MD5:
175         case ENCTYPE_DES_CBC_RAW:
176                 /* Old format of context to the kernel */
177                 if (kctx->initiate) {
178                         if (WRITE_BYTES(&p, end, constant_one)) goto out_err;
179                 }
180                 else {
181                         if (WRITE_BYTES(&p, end, constant_zero)) goto out_err;
182                 }
183                 if (kctx->seed_init) {
184                         if (WRITE_BYTES(&p, end, constant_one)) goto out_err;
185                 }
186                 else {
187                         if (WRITE_BYTES(&p, end, constant_zero)) goto out_err;
188                 }
189                 if (write_bytes(&p, end, &kctx->seed, sizeof(kctx->seed)))
190                         goto out_err;
191                 if (WRITE_BYTES(&p, end, kctx->signalg)) goto out_err;
192                 if (WRITE_BYTES(&p, end, kctx->sealalg)) goto out_err;
193                 if (WRITE_BYTES(&p, end, kctx->endtime)) goto out_err;
194                 if (endtime)
195                         *endtime = kctx->endtime;
196                 word_seq_send = kctx->seq_send;
197                 if (WRITE_BYTES(&p, end, word_seq_send)) goto out_err;
198                 if (write_oid(&p, end, kctx->mech_used)) goto out_err;
199
200                 printerr(2, "serialize_krb5_ctx: serializing keys with "
201                          "enctype %d and length %d\n",
202                          kctx->enc->enctype, kctx->enc->length);
203
204                 if (write_keyblock(&p, end, kctx->enc)) goto out_err;
205                 if (write_keyblock(&p, end, kctx->seq)) goto out_err;
206                 break;
207         case ENCTYPE_DES3_CBC_RAW:
208         case ENCTYPE_DES3_CBC_SHA1:
209         case ENCTYPE_ARCFOUR_HMAC:
210         case ENCTYPE_ARCFOUR_HMAC_EXP:
211         case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
212         case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
213                 /* New format of context to the kernel */
214                 /* u32 flags;
215                  * #define KRB5_CTX_FLAG_INITIATOR        0x00000001
216                  * #define KRB5_CTX_FLAG_CFX              0x00000002
217                  * #define KRB5_CTX_FLAG_ACCEPTOR_SUBKEY  0x00000004
218                  * s32 endtime;
219                  * u64 seq_send;
220                  * u32  enctype;
221                  * rawkey data
222                  */
223
224                 if (kctx->initiate)
225                         v2_flags |= KRB5_CTX_FLAG_INITIATOR;
226                 if (kctx->proto == 1)
227                         v2_flags |= KRB5_CTX_FLAG_CFX;
228                 if (kctx->have_acceptor_subkey)
229                         v2_flags |= KRB5_CTX_FLAG_ACCEPTOR_SUBKEY;
230                 if (WRITE_BYTES(&p, end, v2_flags)) goto out_err;
231                 if (WRITE_BYTES(&p, end, kctx->endtime)) goto out_err;
232
233                 seq_send_64bit = kctx->seq_send;
234                 if (WRITE_BYTES(&p, end, seq_send_64bit)) goto out_err;
235
236                 if (kctx->have_acceptor_subkey) {
237                         if (WRITE_BYTES(&p, end, kctx->acceptor_subkey->enctype))
238                                 goto out_err;
239                         printerr(2, "serialize_krb5_ctx: serializing subkey "
240                                  "with enctype %d and size %d\n",
241                                  kctx->acceptor_subkey->enctype,
242                                  kctx->acceptor_subkey->length);
243
244                         if (write_bytes(&p, end,
245                                         kctx->acceptor_subkey->contents,
246                                         kctx->acceptor_subkey->length))
247                                 goto out_err;
248                 } else {
249                         if (WRITE_BYTES(&p, end, kctx->enc->enctype))
250                                 goto out_err;
251                         printerr(2, "serialize_krb5_ctx: serializing key "
252                                  "with enctype %d and size %d\n",
253                                  kctx->enc->enctype, kctx->enc->length);
254
255                         if (write_bytes(&p, end, kctx->enc->contents,
256                                         kctx->enc->length))
257                                 goto out_err;
258                 }
259                 break;
260         default:
261                 printerr(0, "ERROR: serialize_krb5_ctx: unsupported encryption "
262                          "algorithm %d\n", kctx->enc->enctype);
263                 goto out_err;
264         }
265
266         buf->length = p - (char *)buf->value;
267         return 0;
268
269 out_err:
270         printerr(0, "ERROR: failed serializing krb5 context for kernel\n");
271         if (buf->value) {
272                 free(buf->value);
273         }
274         buf->value = NULL;
275         buf->length = 0;
276         return -1;
277 }
278
279 #endif /* HAVE_KRB5 */
280 #endif /* HAVE_LUCID_CONTEXT_SUPPORT */