1 /* GSSAPI/krb5 support for FTP - loosely based on old krb4.c
2 *
3 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan
4 * (Royal Institute of Technology, Stockholm, Sweden).
5 * Copyright (c) 2004 - 2008 Daniel Stenberg
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE. */
34
35 #include "setup.h"
36
37 #ifndef CURL_DISABLE_FTP
38 #ifdef HAVE_GSSAPI
39
40 #ifdef HAVE_OLD_GSSMIT
41 #define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
42 #endif
43
44 #include <stdlib.h>
45 #ifdef HAVE_NETDB_H
46 #include <netdb.h>
47 #endif
48 #include <string.h>
49 #ifdef HAVE_GSSMIT
50 /* MIT style */
51 #include <gssapi/gssapi.h>
52 #include <gssapi/gssapi_generic.h>
53 #include <gssapi/gssapi_krb5.h>
54 #else
55 /* Heimdal-style */
56 #include <gssapi.h>
57 #endif
58
59 #include "urldata.h"
60 #include "curl_base64.h"
61 #include "ftp.h"
62 #include "sendf.h"
63 #include "krb4.h"
64 #include "memory.h"
65
66 #define _MPRINTF_REPLACE /* use our functions only */
67 #include <curl/mprintf.h>
68
69 /* The last #include file should be: */
70 #include "memdebug.h"
71
72 #define LOCAL_ADDR (&conn->local_addr)
73 #define REMOTE_ADDR conn->ip_addr->ai_addr
74
75 static int
krb5_check_prot(void * app_data,int level)76 krb5_check_prot(void *app_data, int level)
77 {
78 app_data = NULL; /* prevent compiler warning */
79 if(level == prot_confidential)
80 return -1;
81 return 0;
82 }
83
84 static int
krb5_decode(void * app_data,void * buf,int len,int level,struct connectdata * conn)85 krb5_decode(void *app_data, void *buf, int len, int level,
86 struct connectdata *conn)
87 {
88 gss_ctx_id_t *context = app_data;
89 OM_uint32 maj, min;
90 gss_buffer_desc enc, dec;
91
92 /* shut gcc up */
93 level = 0;
94 conn = NULL;
95
96 enc.value = buf;
97 enc.length = len;
98 maj = gss_unseal(&min, *context, &enc, &dec, NULL, NULL);
99 if(maj != GSS_S_COMPLETE) {
100 if(len >= 4)
101 strcpy(buf, "599 ");
102 return -1;
103 }
104
105 memcpy(buf, dec.value, dec.length);
106 len = dec.length;
107 gss_release_buffer(&min, &dec);
108
109 return len;
110 }
111
112 static int
krb5_overhead(void * app_data,int level,int len)113 krb5_overhead(void *app_data, int level, int len)
114 {
115 /* no arguments are used, just init them to prevent compiler warnings */
116 app_data = NULL;
117 level = 0;
118 len = 0;
119 return 0;
120 }
121
122 static int
krb5_encode(void * app_data,const void * from,int length,int level,void ** to,struct connectdata * conn)123 krb5_encode(void *app_data, const void *from, int length, int level, void **to,
124 struct connectdata *conn)
125 {
126 gss_ctx_id_t *context = app_data;
127 gss_buffer_desc dec, enc;
128 OM_uint32 maj, min;
129 int state;
130 int len;
131
132 /* shut gcc up */
133 conn = NULL;
134
135 /* NOTE that the cast is safe, neither of the krb5, gnu gss and heimdal
136 * libraries modify the input buffer in gss_seal()
137 */
138 dec.value = (void*)from;
139 dec.length = length;
140 maj = gss_seal(&min, *context,
141 level == prot_private,
142 GSS_C_QOP_DEFAULT,
143 &dec, &state, &enc);
144
145 if(maj != GSS_S_COMPLETE)
146 return -1;
147
148 /* malloc a new buffer, in case gss_release_buffer doesn't work as expected */
149 *to = malloc(enc.length);
150 if(!*to)
151 return -1;
152 memcpy(*to, enc.value, enc.length);
153 len = enc.length;
154 gss_release_buffer(&min, &enc);
155 return len;
156 }
157
158 static int
krb5_auth(void * app_data,struct connectdata * conn)159 krb5_auth(void *app_data, struct connectdata *conn)
160 {
161 int ret;
162 char *p;
163 const char *host = conn->dns_entry->addr->ai_canonname;
164 ssize_t nread;
165 socklen_t l = sizeof(conn->local_addr);
166 struct SessionHandle *data = conn->data;
167 CURLcode result;
168 const char *service = "ftp", *srv_host = "host";
169 gss_buffer_desc gssbuf, _gssresp, *gssresp;
170 OM_uint32 maj, min;
171 gss_name_t gssname;
172 gss_ctx_id_t *context = app_data;
173 struct gss_channel_bindings_struct chan;
174
175 if(getsockname(conn->sock[FIRSTSOCKET],
176 (struct sockaddr *)LOCAL_ADDR, &l) < 0)
177 perror("getsockname()");
178
179 chan.initiator_addrtype = GSS_C_AF_INET;
180 chan.initiator_address.length = l - 4;
181 chan.initiator_address.value =
182 &((struct sockaddr_in *)LOCAL_ADDR)->sin_addr.s_addr;
183 chan.acceptor_addrtype = GSS_C_AF_INET;
184 chan.acceptor_address.length = l - 4;
185 chan.acceptor_address.value =
186 &((struct sockaddr_in *)REMOTE_ADDR)->sin_addr.s_addr;
187 chan.application_data.length = 0;
188 chan.application_data.value = NULL;
189
190 /* this loop will execute twice (once for service, once for host) */
191 while(1) {
192 /* this really shouldn't be repeated here, but can't help it */
193 if(service == srv_host) {
194 result = Curl_ftpsendf(conn, "AUTH GSSAPI");
195
196 if(result)
197 return -2;
198 if(Curl_GetFTPResponse(&nread, conn, NULL))
199 return -1;
200
201 if(data->state.buffer[0] != '3')
202 return -1;
203 }
204
205 gssbuf.value = data->state.buffer;
206 gssbuf.length = snprintf(gssbuf.value, BUFSIZE, "%s@%s", service, host);
207 maj = gss_import_name(&min, &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &gssname);
208 if(maj != GSS_S_COMPLETE) {
209 gss_release_name(&min, &gssname);
210 if(service == srv_host) {
211 Curl_failf(data, "Error importing service name %s", gssbuf.value);
212 return AUTH_ERROR;
213 }
214 service = srv_host;
215 continue;
216 }
217 {
218 gss_OID t;
219 gss_display_name(&min, gssname, &gssbuf, &t);
220 Curl_infof(data, "Trying against %s\n", gssbuf.value);
221 gss_release_buffer(&min, &gssbuf);
222 }
223 gssresp = GSS_C_NO_BUFFER;
224 *context = GSS_C_NO_CONTEXT;
225
226 do {
227 ret = AUTH_OK;
228 maj = gss_init_sec_context(&min,
229 GSS_C_NO_CREDENTIAL,
230 context,
231 gssname,
232 GSS_C_NO_OID,
233 GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG,
234 0,
235 &chan,
236 gssresp,
237 NULL,
238 &gssbuf,
239 NULL,
240 NULL);
241
242 if(gssresp) {
243 free(_gssresp.value);
244 gssresp = NULL;
245 }
246
247 if(maj != GSS_S_COMPLETE && maj != GSS_S_CONTINUE_NEEDED) {
248 Curl_infof(data, "Error creating security context");
249 ret = AUTH_ERROR;
250 break;
251 }
252
253 if(gssbuf.length != 0) {
254 if(Curl_base64_encode(data, (char *)gssbuf.value, gssbuf.length, &p)
255 < 1) {
256 Curl_infof(data, "Out of memory base64-encoding");
257 ret = AUTH_CONTINUE;
258 break;
259 }
260
261 result = Curl_ftpsendf(conn, "ADAT %s", p);
262
263 free(p);
264
265 if(result) {
266 ret = -2;
267 break;
268 }
269
270 if(Curl_GetFTPResponse(&nread, conn, NULL)) {
271 ret = -1;
272 break;
273 }
274
275 if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3'){
276 Curl_infof(data, "Server didn't accept auth data\n");
277 ret = AUTH_ERROR;
278 break;
279 }
280
281 p = data->state.buffer + 4;
282 p = strstr(p, "ADAT=");
283 if(p) {
284 _gssresp.length = Curl_base64_decode(p + 5, (unsigned char **)
285 &_gssresp.value);
286 if(_gssresp.length < 1) {
287 Curl_failf(data, "Out of memory base64-encoding");
288 ret = AUTH_CONTINUE;
289 break;
290 }
291 }
292
293 gssresp = &_gssresp;
294 }
295 } while(maj == GSS_S_CONTINUE_NEEDED);
296
297 gss_release_name(&min, &gssname);
298
299 if(gssresp)
300 free(_gssresp.value);
301
302 if(ret == AUTH_OK || service == srv_host)
303 return ret;
304
305 service = srv_host;
306 }
307 }
308
309 struct Curl_sec_client_mech Curl_krb5_client_mech = {
310 "GSSAPI",
311 sizeof(gss_ctx_id_t),
312 NULL, /* init */
313 krb5_auth,
314 NULL, /* end */
315 krb5_check_prot,
316 krb5_overhead,
317 krb5_encode,
318 krb5_decode
319 };
320
321 #endif /* HAVE_GSSAPI */
322 #endif /* CURL_DISABLE_FTP */
323