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 - 2011 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#define NCOMPAT 1 43#endif 44 45#ifdef HAVE_NETDB_H 46#include <netdb.h> 47#endif 48 49#include "urldata.h" 50#include "curl_base64.h" 51#include "ftp.h" 52#include "curl_gssapi.h" 53#include "sendf.h" 54#include "krb4.h" 55#include "curl_memory.h" 56 57#define _MPRINTF_REPLACE /* use our functions only */ 58#include <curl/mprintf.h> 59 60/* The last #include file should be: */ 61#include "memdebug.h" 62 63#define LOCAL_ADDR (&conn->local_addr) 64#define REMOTE_ADDR conn->ip_addr->ai_addr 65 66static int 67krb5_init(void *app_data) 68{ 69 gss_ctx_id_t *context = app_data; 70 /* Make sure our context is initialized for krb5_end. */ 71 *context = GSS_C_NO_CONTEXT; 72 return 0; 73} 74 75static int 76krb5_check_prot(void *app_data, int level) 77{ 78 (void)app_data; /* unused */ 79 if(level == PROT_CONFIDENTIAL) 80 return -1; 81 return 0; 82} 83 84static int 85krb5_decode(void *app_data, void *buf, int len, 86 int level UNUSED_PARAM, 87 struct connectdata *conn UNUSED_PARAM) 88{ 89 gss_ctx_id_t *context = app_data; 90 OM_uint32 maj, min; 91 gss_buffer_desc enc, dec; 92 93 (void)level; 94 (void)conn; 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 112static int 113krb5_overhead(void *app_data, int level, int len) 114{ 115 /* no arguments are used */ 116 (void)app_data; 117 (void)level; 118 (void)len; 119 return 0; 120} 121 122static int 123krb5_encode(void *app_data, const void *from, int length, int level, void **to, 124 struct connectdata *conn UNUSED_PARAM) 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 149 expected */ 150 *to = malloc(enc.length); 151 if(!*to) 152 return -1; 153 memcpy(*to, enc.value, enc.length); 154 len = enc.length; 155 gss_release_buffer(&min, &enc); 156 return len; 157} 158 159static int 160krb5_auth(void *app_data, struct connectdata *conn) 161{ 162 int ret = AUTH_OK; 163 char *p; 164 const char *host = conn->host.name; 165 ssize_t nread; 166 curl_socklen_t l = sizeof(conn->local_addr); 167 struct SessionHandle *data = conn->data; 168 CURLcode result; 169 const char *service = "ftp", *srv_host = "host"; 170 gss_buffer_desc input_buffer, output_buffer, _gssresp, *gssresp; 171 OM_uint32 maj, min; 172 gss_name_t gssname; 173 gss_ctx_id_t *context = app_data; 174 struct gss_channel_bindings_struct chan; 175 size_t base64_sz = 0; 176 177 if(getsockname(conn->sock[FIRSTSOCKET], 178 (struct sockaddr *)LOCAL_ADDR, &l) < 0) 179 perror("getsockname()"); 180 181 chan.initiator_addrtype = GSS_C_AF_INET; 182 chan.initiator_address.length = l - 4; 183 chan.initiator_address.value = 184 &((struct sockaddr_in *)LOCAL_ADDR)->sin_addr.s_addr; 185 chan.acceptor_addrtype = GSS_C_AF_INET; 186 chan.acceptor_address.length = l - 4; 187 chan.acceptor_address.value = 188 &((struct sockaddr_in *)REMOTE_ADDR)->sin_addr.s_addr; 189 chan.application_data.length = 0; 190 chan.application_data.value = NULL; 191 192 /* this loop will execute twice (once for service, once for host) */ 193 for(;;) { 194 /* this really shouldn't be repeated here, but can't help it */ 195 if(service == srv_host) { 196 result = Curl_ftpsendf(conn, "AUTH GSSAPI"); 197 198 if(result) 199 return -2; 200 if(Curl_GetFTPResponse(&nread, conn, NULL)) 201 return -1; 202 203 if(data->state.buffer[0] != '3') 204 return -1; 205 } 206 207 input_buffer.value = data->state.buffer; 208 input_buffer.length = snprintf(input_buffer.value, BUFSIZE, "%s@%s", 209 service, host); 210 maj = gss_import_name(&min, &input_buffer, GSS_C_NT_HOSTBASED_SERVICE, 211 &gssname); 212 if(maj != GSS_S_COMPLETE) { 213 gss_release_name(&min, &gssname); 214 if(service == srv_host) { 215 Curl_failf(data, "Error importing service name %s", 216 input_buffer.value); 217 return AUTH_ERROR; 218 } 219 service = srv_host; 220 continue; 221 } 222 /* We pass NULL as |output_name_type| to avoid a leak. */ 223 gss_display_name(&min, gssname, &output_buffer, NULL); 224 Curl_infof(data, "Trying against %s\n", output_buffer.value); 225 gssresp = GSS_C_NO_BUFFER; 226 *context = GSS_C_NO_CONTEXT; 227 228 do { 229 /* Release the buffer at each iteration to avoid leaking: the first time 230 we are releasing the memory from gss_display_name. The last item is 231 taken care by a final gss_release_buffer. */ 232 gss_release_buffer(&min, &output_buffer); 233 ret = AUTH_OK; 234 maj = Curl_gss_init_sec_context(data, 235 &min, 236 context, 237 gssname, 238 &chan, 239 gssresp, 240 &output_buffer, 241 NULL); 242 243 if(gssresp) { 244 free(_gssresp.value); 245 gssresp = NULL; 246 } 247 248 if(GSS_ERROR(maj)) { 249 Curl_infof(data, "Error creating security context\n"); 250 ret = AUTH_ERROR; 251 break; 252 } 253 254 if(output_buffer.length != 0) { 255 result = Curl_base64_encode(data, (char *)output_buffer.value, 256 output_buffer.length, &p, &base64_sz); 257 if(result) { 258 Curl_infof(data,"base64-encoding: %s\n", curl_easy_strerror(result)); 259 ret = AUTH_CONTINUE; 260 break; 261 } 262 263 result = Curl_ftpsendf(conn, "ADAT %s", p); 264 265 free(p); 266 267 if(result) { 268 ret = -2; 269 break; 270 } 271 272 if(Curl_GetFTPResponse(&nread, conn, NULL)) { 273 ret = -1; 274 break; 275 } 276 277 if(data->state.buffer[0] != '2' && data->state.buffer[0] != '3') { 278 Curl_infof(data, "Server didn't accept auth data\n"); 279 ret = AUTH_ERROR; 280 break; 281 } 282 283 p = data->state.buffer + 4; 284 p = strstr(p, "ADAT="); 285 if(p) { 286 result = Curl_base64_decode(p + 5, 287 (unsigned char **)&_gssresp.value, 288 &_gssresp.length); 289 if(result) { 290 Curl_failf(data,"base64-decoding: %s", curl_easy_strerror(result)); 291 ret = AUTH_CONTINUE; 292 break; 293 } 294 } 295 296 gssresp = &_gssresp; 297 } 298 } while(maj == GSS_S_CONTINUE_NEEDED); 299 300 gss_release_name(&min, &gssname); 301 gss_release_buffer(&min, &output_buffer); 302 303 if(gssresp) 304 free(_gssresp.value); 305 306 if(ret == AUTH_OK || service == srv_host) 307 return ret; 308 309 service = srv_host; 310 } 311 return ret; 312} 313 314static void krb5_end(void *app_data) 315{ 316 OM_uint32 maj, min; 317 gss_ctx_id_t *context = app_data; 318 if(*context != GSS_C_NO_CONTEXT) { 319 maj = gss_delete_sec_context(&min, context, GSS_C_NO_BUFFER); 320 DEBUGASSERT(maj == GSS_S_COMPLETE); 321 } 322} 323 324struct Curl_sec_client_mech Curl_krb5_client_mech = { 325 "GSSAPI", 326 sizeof(gss_ctx_id_t), 327 krb5_init, 328 krb5_auth, 329 krb5_end, 330 krb5_check_prot, 331 krb5_overhead, 332 krb5_encode, 333 krb5_decode 334}; 335 336#endif /* HAVE_GSSAPI */ 337#endif /* CURL_DISABLE_FTP */ 338