source/nsswitch/wb_common.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 2.0
   4
   5    winbind client common code
   6
   7    Copyright (C) Tim Potter 2000
   8    Copyright (C) Andrew Tridgell 2000
   9
  10    This library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Library General Public
  12    License as published by the Free Software Foundation; either
  13    version 2 of the License, or (at your option) any later version.
  14
  15    This library is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Library General Public License for more details.
  19
  20    You should have received a copy of the GNU Library General Public
  21    License along with this library; if not, write to the
  22    Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23    Boston, MA  02111-1307, USA.
  24 */
  25
  26 #include "winbind_nss_config.h"
  27 #include "winbindd_nss.h"
  28
  29 /* Global variables.  These are effectively the client state information */
  30
  31 static int established_socket = -1;           /* fd for winbindd socket */
  32 static char *excluded_domain;
  33
  34 /*
  35   smbd needs to be able to exclude lookups for its own domain
  36 */
  37 void winbind_exclude_domain(const char *domain)
  38 {
  39         SAFE_FREE(excluded_domain);
  40         excluded_domain = strdup(domain);
  41 }
  42
  43
  44 /* Initialise a request structure */
  45
  46 void init_request(struct winbindd_request *request, int request_type)
  47 {
  48         static char *domain_env;
  49         static BOOL initialised;
  50
  51         request->cmd = (enum winbindd_cmd)request_type;
  52         request->pid = getpid();
  53         request->domain[0] = '\0';
  54
  55         if (!initialised) {
  56                 initialised = True;
  57                 domain_env = getenv(WINBINDD_DOMAIN_ENV);
  58         }
  59
  60         if (domain_env) {
  61                 strncpy(request->domain, domain_env,
  62                         sizeof(request->domain) - 1);
  63                 request->domain[sizeof(request->domain) - 1] = '\0';
  64         }
  65 }
  66
  67 /* Initialise a response structure */
  68
  69 void init_response(struct winbindd_response *response)
  70 {
  71         /* Initialise return value */
  72
  73         response->result = WINBINDD_ERROR;
  74 }
  75
  76 /* Close established socket */
  77
  78 void close_sock(void)
  79 {
  80         if (established_socket != -1) {
  81                 close(established_socket);
  82                 established_socket = -1;
  83         }
  84 }
  85
  86 /* Connect to winbindd socket */
  87
  88 static int open_pipe_sock(void)
  89 {
  90         struct sockaddr_un sunaddr;
  91         static pid_t our_pid;
  92         struct stat st;
  93         pstring path;
  94
  95         if (our_pid != getpid()) {
  96                 if (established_socket != -1) {
  97                         close(established_socket);
  98                 }
  99                 established_socket = -1;
 100                 our_pid = getpid();
 101         }
 102
 103         if (established_socket != -1) {
 104                 return established_socket;
 105         }
 106
 107         /* Check permissions on unix socket directory */
 108
 109         if (lstat(WINBINDD_SOCKET_DIR, &st) == -1) {
 110                 return -1;
 111         }
 112
 113         if (!S_ISDIR(st.st_mode) ||
 114             (st.st_uid != 0 && st.st_uid != geteuid())) {
 115                 return -1;
 116         }
 117
 118         /* Connect to socket */
 119
 120         strncpy(path, WINBINDD_SOCKET_DIR, sizeof(path) - 1);
 121         path[sizeof(path) - 1] = '\0';
 122
 123         strncat(path, "/", sizeof(path) - 1);
 124         path[sizeof(path) - 1] = '\0';
 125
 126         strncat(path, WINBINDD_SOCKET_NAME, sizeof(path) - 1);
 127         path[sizeof(path) - 1] = '\0';
 128
 129         ZERO_STRUCT(sunaddr);
 130         sunaddr.sun_family = AF_UNIX;
 131         strncpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path) - 1);
 132
 133         /* If socket file doesn't exist, don't bother trying to connect
 134            with retry.  This is an attempt to make the system usable when
 135            the winbindd daemon is not running. */
 136
 137         if (lstat(path, &st) == -1) {
 138                 return -1;
 139         }
 140
 141         /* Check permissions on unix socket file */
 142
 143         if (!S_ISSOCK(st.st_mode) ||
 144             (st.st_uid != 0 && st.st_uid != geteuid())) {
 145                 return -1;
 146         }
 147
 148         /* Connect to socket */
 149
 150         if ((established_socket = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 151                 return -1;
 152         }
 153
 154         if (connect(established_socket, (struct sockaddr *)&sunaddr,
 155                     sizeof(sunaddr)) == -1) {
 156                 close_sock();
 157                 established_socket = -1;
 158                 return -1;
 159         }
 160
 161         return established_socket;
 162 }
 163
 164 /* Write data to winbindd socket with timeout */
 165
 166 int write_sock(void *buffer, int count)
 167 {
 168         int result, nwritten;
 169
 170         /* Open connection to winbind daemon */
 171
 172  restart:
 173
 174         if (open_pipe_sock() == -1) {
 175                 return -1;
 176         }
 177
 178         /* Write data to socket */
 179
 180         nwritten = 0;
 181
 182         while(nwritten < count) {
 183                 struct timeval tv;
 184                 fd_set r_fds;
 185                 int selret;
 186
 187                 /* Catch pipe close on other end by checking if a read()
 188                    call would not block by calling select(). */
 189
 190                 FD_ZERO(&r_fds);
 191                 FD_SET(established_socket, &r_fds);
 192                 ZERO_STRUCT(tv);
 193
 194                 if ((selret = select(established_socket + 1, &r_fds,
 195                                      NULL, NULL, &tv)) == -1) {
 196                         close_sock();
 197                         return -1;                   /* Select error */
 198                 }
 199
 200                 /* Write should be OK if fd not available for reading */
 201
 202                 if (!FD_ISSET(established_socket, &r_fds)) {
 203
 204                         /* Do the write */
 205
 206                         result = write(established_socket,
 207                                        (char *)buffer + nwritten,
 208                                        count - nwritten);
 209
 210                         if ((result == -1) || (result == 0)) {
 211
 212                                 /* Write failed */
 213
 214                                 close_sock();
 215                                 return -1;
 216                         }
 217
 218                         nwritten += result;
 219
 220                 } else {
 221
 222                         /* Pipe has closed on remote end */
 223
 224                         close_sock();
 225                         goto restart;
 226                 }
 227         }
 228
 229         return nwritten;
 230 }
 231
 232 /* Read data from winbindd socket with timeout */
 233
 234 static int read_sock(void *buffer, int count)
 235 {
 236         int result = 0, nread = 0;
 237
 238         /* Read data from socket */
 239
 240         while(nread < count) {
 241
 242                 result = read(established_socket, (char *)buffer + nread,
 243                               count - nread);
 244
 245                 if ((result == -1) || (result == 0)) {
 246
 247                         /* Read failed.  I think the only useful thing we
 248                            can do here is just return -1 and fail since the
 249                            transaction has failed half way through. */
 250
 251                         close_sock();
 252                         return -1;
 253                 }
 254
 255                 nread += result;
 256         }
 257
 258         return result;
 259 }
 260
 261 /* Read reply */
 262
 263 int read_reply(struct winbindd_response *response)
 264 {
 265         int result1, result2 = 0;
 266
 267         if (!response) {
 268                 return -1;
 269         }
 270
 271         /* Read fixed length response */
 272
 273         if ((result1 = read_sock(response, sizeof(struct winbindd_response)))
 274             == -1) {
 275
 276                 return -1;
 277         }
 278
 279         /* We actually send the pointer value of the extra_data field from
 280            the server.  This has no meaning in the client's address space
 281            so we clear it out. */
 282
 283         response->extra_data = NULL;
 284
 285         /* Read variable length response */
 286
 287         if (response->length > sizeof(struct winbindd_response)) {
 288                 int extra_data_len = response->length -
 289                         sizeof(struct winbindd_response);
 290
 291                 /* Mallocate memory for extra data */
 292
 293                 if (!(response->extra_data = malloc(extra_data_len))) {
 294                         return -1;
 295                 }
 296
 297                 if ((result2 = read_sock(response->extra_data, extra_data_len))
 298                     == -1) {
 299                         return -1;
 300                 }
 301         }
 302
 303         /* Return total amount of data read */
 304
 305         return result1 + result2;
 306 }
 307
 308 /* Free a response structure */
 309
 310 void free_response(struct winbindd_response *response)
 311 {
 312         /* Free any allocated extra_data */
 313
 314         if (response)
 315                 SAFE_FREE(response->extra_data);
 316 }
 317
 318 /* Handle simple types of requests */
 319
 320 NSS_STATUS winbindd_request(int req_type,
 321                                  struct winbindd_request *request,
 322                                  struct winbindd_response *response)
 323 {
 324         struct winbindd_request lrequest;
 325         struct winbindd_response lresponse;
 326
 327         /* Check for our tricky environment variable */
 328
 329         if (getenv(WINBINDD_DONT_ENV)) {
 330                 return NSS_STATUS_NOTFOUND;
 331         }
 332
 333         /* smbd may have excluded this domain */
 334         if (excluded_domain &&
 335             strcasecmp(excluded_domain, request->domain) == 0) {
 336                 return NSS_STATUS_NOTFOUND;
 337         }
 338
 339         if (!response) {
 340                 ZERO_STRUCT(lresponse);
 341                 response = &lresponse;
 342         }
 343
 344         if (!request) {
 345                 ZERO_STRUCT(lrequest);
 346                 request = &lrequest;
 347         }
 348
 349         /* Fill in request and send down pipe */
 350
 351         init_request(request, req_type);
 352         init_response(response);
 353
 354         if (write_sock(request, sizeof(*request)) == -1) {
 355                 return NSS_STATUS_UNAVAIL;
 356         }
 357
 358         /* Wait for reply */
 359         if (read_reply(response) == -1) {
 360                 return NSS_STATUS_UNAVAIL;
 361         }
 362
 363         /* Throw away extra data if client didn't request it */
 364         if (response == &lresponse) {
 365                 free_response(response);
 366         }
 367
 368         /* Copy reply data from socket */
 369         if (response->result != WINBINDD_OK) {
 370                 return NSS_STATUS_NOTFOUND;
 371         }
 372
 373         return NSS_STATUS_SUCCESS;
 374 }