aboutsummaryrefslogtreecommitdiff
path: root/lib/krb5.c
blob: 6655973d4edc451540817c635d59db58bc61c2a8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
/* This source code was modified by Martin Hedenfalk <mhe@stacken.kth.se> for
 * use in Curl. His latest changes were done 2000-09-18.
 *
 * It has since been patched away like a madman by Daniel Stenberg
 * <daniel@haxx.se> to make it better applied to curl conditions, and to make
 * it not use globals, pollute name space and more. This source code awaits a
 * rewrite to work around the paragraph 2 in the BSD licenses as explained
 * below.
 *
 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.  */

#include "setup.h"

#ifndef CURL_DISABLE_FTP
#ifdef HAVE_GSSAPI

#include <stdlib.h>
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#include <string.h>
#include <gssapi/gssapi.h>
#include <gssapi/gssapi_generic.h>
#include <gssapi/gssapi_krb5.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h> /* for getpid() */
#endif

#include "urldata.h"
#include "base64.h"
#include "ftp.h"
#include "sendf.h"
#include "krb4.h"
#include "memory.h"

#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
#include "inet_ntoa_r.h"
#endif

/* The last #include file should be: */
#include "memdebug.h"

#define LOCAL_ADDR (&conn->local_addr)
#define REMOTE_ADDR conn->ip_addr->ai_addr
#define myctladdr LOCAL_ADDR
#define hisctladdr REMOTE_ADDR

static int
krb5_check_prot(void *app_data, int level)
{
  gss_ctx_id_t *context = app_data;
  app_data = NULL; /* prevent compiler warning */
  if(level == prot_confidential)
    return -1;
  return 0;
}

static int
krb5_decode(void *app_data, void *buf, int len, int level,
            struct connectdata *conn)
{
  gss_ctx_id_t *context = app_data;
  OM_uint32 maj, min;
  gss_buffer_desc enc, dec;

  enc.value = buf;
  enc.length = len;
  maj = gss_unseal(&min, *context, &enc, &dec, NULL, NULL);
  if(maj != GSS_S_COMPLETE) {
    if(len >= 4)
      strcpy(buf, "599 ");
    return -1;
  }

  memcpy(buf, dec.value, dec.length);
  len = dec.length;
  gss_release_buffer(&min, &dec);

  return len;
}

static int
krb5_overhead(void *app_data, int level, int len)
{
  gss_ctx_id_t *context = app_data;
  /* no arguments are used, just init them to prevent compiler warnings */
  app_data = NULL;
  level = 0;
  len = 0;
  return 0;
}

static int
krb5_encode(void *app_data, void *from, int length, int level, void **to,
            struct connectdata *conn)
{
  gss_ctx_id_t *context = app_data;
  gss_buffer_desc dec, enc;
  OM_uint32 maj, min;
  int state;
  int len;

  dec.value = from;
  dec.length = length;
  maj = gss_seal(&min, *context,
		 level == prot_private,
		 GSS_C_QOP_DEFAULT,
		 &dec, &state, &enc);

  if(maj != GSS_S_COMPLETE)
    return -1;

  /* malloc a new buffer, in case gss_release_buffer doesn't work as expected */
  *to = malloc(enc.length);
  if(!*to)
    return -1;
  memcpy(*to, enc.value, enc.length);
  len = enc.length;
  gss_release_buffer(&min, &enc);
  return len;
}

static int
krb5_auth(void *app_data, struct connectdata *conn)
{
  int ret;
  char *p;
  unsigned char *ptr;
  size_t len;
  u_int32_t cs;
  const char *host = conn->dns_entry->addr->ai_canonname;
  ssize_t nread;
  unsigned int l = sizeof(conn->local_addr);
  struct SessionHandle *data = conn->data;
  CURLcode result;
  const char *service = "ftp", *srv_host = "host";
  gss_buffer_desc gssbuf, _gssresp, *gssresp;
  OM_uint32 maj, min;
  gss_name_t gssname;
  gss_ctx_id_t *context = app_data;
  struct gss_channel_bindings_struct chan;

  if(getsockname(conn->sock[FIRSTSOCKET],
                 (struct sockaddr *)LOCAL_ADDR, &l) < 0)
    perror("getsockname()");

  chan.initiator_addrtype = GSS_C_AF_INET;
  chan.initiator_address.length = l - 4;
  chan.initiator_address.value = &((struct sockaddr_in *)LOCAL_ADDR)->sin_addr.s_addr;
  chan.acceptor_addrtype = GSS_C_AF_INET;
  chan.acceptor_address.length = l - 4;
  chan.acceptor_address.value = &((struct sockaddr_in *)REMOTE_ADDR)->sin_addr.s_addr;
  chan.application_data.length = 0;
  chan.application_data.value = NULL;

  /* this loop will execute twice (once for service, once for host) */
  while(1) {
    /* this really shouldn't be repeated here, but can't help it */
    if(service == srv_host) {
      result = Curl_ftpsendf(conn, "AUTH GSSAPI");

      if(result)
	return -2;
      if(Curl_GetFTPResponse(&nread, conn, NULL))
	return -1;

      if(data->state.buffer[0] != '3')
	return -1;
    }

    gssbuf.value = data->state.buffer;
    gssbuf.length = snprintf(gssbuf.value, BUFSIZE, "%s@%s", service, host);
    maj = gss_import_name(&min, &gssbuf, gss_nt_service_name, &gssname);
    if(maj != GSS_S_COMPLETE) {
      gss_release_name(&min, &gssname);
      if(service == srv_host) {
	Curl_failf(data, "Error importing service name %s", gssbuf.value);
	return AUTH_ERROR;
      }
      service = srv_host;
      continue;
    }
    {
      gss_OID t;
      gss_display_name(&min, gssname, &gssbuf, &t);
      Curl_infof(data, "Trying against %s\n", gssbuf.value);
      gss_release_buffer(&min, &gssbuf);
    }
    gssresp = GSS_C_NO_BUFFER;
    *context = GSS_C_NO_CONTEXT;

    do {
      ret = AUTH_OK;
      maj = gss_init_sec_context(&min,
				 GSS_C_NO_CREDENTIAL,
				 context,
				 gssname,
				 GSS_C_NO_OID,
				 GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG,
				 0,
				 &chan,
				 gssresp,
				 NULL,
				 &gssbuf,
				 NULL,
				 NULL);

      if(gssresp) {
	free(_gssresp.value);
	gssresp = NULL;
      }

      if(maj != GSS_S_COMPLETE && maj != GSS_S_CONTINUE_NEEDED) {
	Curl_infof(data, "Error creating security context");
	ret = AUTH_ERROR;
	break;
      }

      if(gssbuf.length != 0) {
	if(Curl_base64_encode(data, (char *)gssbuf.value, gssbuf.length, &p) < 1) {
	  Curl_infof(data, "Out of memory base64-encoding");
	  ret = AUTH_CONTINUE;
	  break;
	}

	result = Curl_ftpsendf(conn, "ADAT %s", p);

	free(p);

	if(result) {
	  ret = -2;
	  break;
	}

	if(Curl_GetFTPResponse(&nread, conn, NULL)) {
	  ret = -1;
	  break;
	}

	if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3'){
	  Curl_infof(data, "Server didn't accept auth data\n");
	  ret = AUTH_ERROR;
	  break;
	}

	p = data->state.buffer + 4;
	p = strstr(p, "ADAT=");
	if(p) {
	  _gssresp.length = Curl_base64_decode(p + 5, (unsigned char **)&_gssresp.value);
	  if(_gssresp.length < 1) {
	    Curl_failf(data, "Out of memory base64-encoding");
	    ret = AUTH_CONTINUE;
	    break;
	  }
	}

	gssresp = &_gssresp;
      }
    } while(maj == GSS_S_CONTINUE_NEEDED);

    gss_release_name(&min, &gssname);

    if(gssresp)
      free(_gssresp.value);

    if(ret == AUTH_OK || service == srv_host)
      return ret;

    service = srv_host;
  }
}

struct Curl_sec_client_mech Curl_krb5_client_mech = {
    "GSSAPI",
    sizeof(gss_ctx_id_t),
    NULL, /* init */
    krb5_auth,
    NULL, /* end */
    krb5_check_prot,
    krb5_overhead,
    krb5_encode,
    krb5_decode
};

#endif /* HAVE_GSSAPI */
#endif /* CURL_DISABLE_FTP */