src/src/auths/pwcheck.c

   1 /* SASL server API implementation
   2  * Rob Siemborski
   3  * Tim Martin
   4  * $Id: checkpw.c,v 1.49 2002/03/07 19:14:04 ken3 Exp $
   5  */
   6 /*
   7  * Copyright (c) 2001 Carnegie Mellon University.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * 3. The name "Carnegie Mellon University" must not be used to
  22  *    endorse or promote products derived from this software without
  23  *    prior written permission. For permission or any other legal
  24  *    details, please contact
  25  *      Office of Technology Transfer
  26  *      Carnegie Mellon University
  27  *      5000 Forbes Avenue
  28  *      Pittsburgh, PA  15213-3890
  29  *      (412) 268-4387, fax: (412) 268-7395
  30  *      tech-transfer@andrew.cmu.edu
  31  *
  32  * 4. Redistributions of any form whatsoever must retain the following
  33  *    acknowledgment:
  34  *    "This product includes software developed by Computing Services
  35  *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
  36  *
  37  * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
  38  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  39  * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
  40  * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  41  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
  42  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  43  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  44  */
  45
  46 /*
  47  * Taken from Cyrus-SASL library and adapted by Alexander S. Sabourenkov
  48  * Oct 2001 - Apr 2002: Slightly modified by Philip Hazel.
  49  * Aug 2003: new code for saslauthd from Alexander S. Sabourenkov incorporated
  50  *           by Philip Hazel (minor mods to avoid compiler warnings)
  51  * Oct 2006: (PH) removed redundant tests on "reply" being NULL - some were
  52  *           missing, and confused someone who was using this code for some
  53  *           other purpose. Here in Exim, "reply" is never NULL.
  54  *
  55  * screwdriver@lxnt.info
  56  *
  57  */
  58
  59 /* Originally this module supported only the pwcheck daemon, which is where its
  60 name comes from. Nowadays it supports saslauthd as well; pwcheck is in fact
  61 deprecated. The definitions of CYRUS_PWCHECK_SOCKET and CYRUS_SASLAUTHD_SOCKET
  62 determine whether the facilities are actually supported or not. */
  63
  64
  65 #include "../exim.h"
  66 #include "pwcheck.h"
  67
  68
  69 #if defined(CYRUS_PWCHECK_SOCKET) || defined(CYRUS_SASLAUTHD_SOCKET)
  70
  71 #include <sys/uio.h>
  72
  73 static int retry_read(int, void *, unsigned );
  74 static int retry_writev(int, struct iovec *, int );
  75 static int read_string(int, uschar **);
  76 static int write_string(int, const uschar *, int);
  77
  78 #endif
  79
  80
  81 /* A dummy function that always fails if pwcheck support is not
  82 wanted. */
  83
  84 #ifndef CYRUS_PWCHECK_SOCKET
  85 int pwcheck_verify_password(const char *userid,
  86                             const char *passwd,
  87                             const char **reply)
  88 {
  89 userid = userid;  /* Keep picky compilers happy */
  90 passwd = passwd;
  91 *reply = "pwcheck support is not included in this Exim binary";
  92 return PWCHECK_FAIL;
  93 }
  94
  95
  96 /* This is the real function */
  97
  98 #else
  99
 100  /* taken from cyrus-sasl file checkpw.c */
 101  /* pwcheck daemon-authenticated login */
 102  int pwcheck_verify_password(const char *userid,
 103                                   const char *passwd,
 104                                   const char **reply)
 105  {
 106      int s, start, r, n;
 107      struct sockaddr_un srvaddr;
 108      struct iovec iov[2];
 109      static char response[1024];
 110
 111      *reply = NULL;
 112
 113      s = socket(AF_UNIX, SOCK_STREAM, 0);
 114      if (s == -1) { return PWCHECK_FAIL; }
 115
 116      memset((char *)&srvaddr, 0, sizeof(srvaddr));
 117      srvaddr.sun_family = AF_UNIX;
 118      strncpy(srvaddr.sun_path, CYRUS_PWCHECK_SOCKET, sizeof(srvaddr.sun_path));
 119      r = connect(s, (struct sockaddr *)&srvaddr, sizeof(srvaddr));
 120      if (r == -1) {
 121         DEBUG(D_auth)
 122             debug_printf("Cannot connect to pwcheck daemon (at '%s')\n",CYRUS_PWCHECK_SOCKET);
 123        *reply = "cannot connect to pwcheck daemon";
 124        return PWCHECK_FAIL;
 125      }
 126
 127      iov[0].iov_base = (char *)userid;
 128      iov[0].iov_len = strlen(userid)+1;
 129      iov[1].iov_base = (char *)passwd;
 130      iov[1].iov_len = strlen(passwd)+1;
 131
 132      retry_writev(s, iov, 2);
 133
 134      start = 0;
 135      while (start < sizeof(response) - 1) {
 136        n = read(s, response+start, sizeof(response) - 1 - start);
 137        if (n < 1) break;
 138        start += n;
 139      }
 140
 141      (void)close(s);
 142
 143      if (start > 1 && !strncmp(response, "OK", 2)) {
 144        return PWCHECK_OK;
 145      }
 146
 147      response[start] = '\0';
 148      *reply = response;
 149      return PWCHECK_NO;
 150  }
 151
 152 #endif
 153
 154
 155
 156  /* A dummy function that always fails if saslauthd support is not
 157 wanted. */
 158
 159 #ifndef CYRUS_SASLAUTHD_SOCKET
 160 int saslauthd_verify_password(const uschar *userid,
 161                 const uschar *passwd,
 162                 const uschar *service,
 163                 const uschar *realm,
 164                 const uschar **reply)
 165 {
 166 userid = userid;  /* Keep picky compilers happy */
 167 passwd = passwd;
 168 service = service;
 169 realm = realm;
 170 *reply = US"saslauthd support is not included in this Exim binary";
 171 return PWCHECK_FAIL;
 172 }
 173
 174
 175 /* This is the real function */
 176
 177 #else
 178  /* written from scratch  */
 179  /* saslauthd daemon-authenticated login */
 180
 181 int saslauthd_verify_password(const uschar *userid,
 182                 const uschar *password,
 183                 const uschar *service,
 184                 const uschar *realm,
 185                 const uschar **reply)
 186 {
 187     uschar *daemon_reply = NULL;
 188     int s, r;
 189     struct sockaddr_un srvaddr;
 190
 191     DEBUG(D_auth)
 192        debug_printf("saslauthd userid='%s' servicename='%s'"
 193                     " realm='%s'\n", userid, service, realm );
 194
 195     *reply = NULL;
 196
 197     s = socket(AF_UNIX, SOCK_STREAM, 0);
 198     if (s == -1) {
 199        *reply = CUstrerror(errno);
 200        return PWCHECK_FAIL;
 201     }
 202
 203     memset((char *)&srvaddr, 0, sizeof(srvaddr));
 204     srvaddr.sun_family = AF_UNIX;
 205     strncpy(srvaddr.sun_path, CYRUS_SASLAUTHD_SOCKET,
 206             sizeof(srvaddr.sun_path));
 207     r = connect(s, (struct sockaddr *)&srvaddr, sizeof(srvaddr));
 208     if (r == -1) {
 209        DEBUG(D_auth)
 210             debug_printf("Cannot connect to saslauthd daemon (at '%s'): %s\n",
 211                          CYRUS_SASLAUTHD_SOCKET, strerror(errno));
 212        *reply = string_sprintf("cannot connect to saslauthd daemon at "
 213                                "%s: %s", CYRUS_SASLAUTHD_SOCKET,
 214                                strerror(errno));
 215        return PWCHECK_FAIL;
 216     }
 217
 218     if ( write_string(s, userid, Ustrlen(userid)) < 0) {
 219         DEBUG(D_auth)
 220             debug_printf("Failed to send userid to saslauthd daemon \n");
 221         (void)close(s);
 222         return PWCHECK_FAIL;
 223     }
 224
 225     if ( write_string(s, password, Ustrlen(password)) < 0) {
 226         DEBUG(D_auth)
 227             debug_printf("Failed to send password to saslauthd daemon \n");
 228         (void)close(s);
 229         return PWCHECK_FAIL;
 230     }
 231
 232     memset((void *)password, 0, Ustrlen(password));
 233
 234     if ( write_string(s, service, Ustrlen(service)) < 0) {
 235         DEBUG(D_auth)
 236             debug_printf("Failed to send service name to saslauthd daemon \n");
 237         (void)close(s);
 238         return PWCHECK_FAIL;
 239     }
 240
 241     if ( write_string(s, realm, Ustrlen(realm)) < 0) {
 242         DEBUG(D_auth)
 243             debug_printf("Failed to send realm to saslauthd daemon \n");
 244         (void)close(s);
 245         return PWCHECK_FAIL;
 246     }
 247
 248     if ( read_string(s, &daemon_reply ) < 2) {
 249         DEBUG(D_auth)
 250             debug_printf("Corrupted answer '%s' received. \n", daemon_reply);
 251         (void)close(s);
 252         return PWCHECK_FAIL;
 253     }
 254
 255     (void)close(s);
 256
 257     DEBUG(D_auth)
 258         debug_printf("Answer '%s' received. \n", daemon_reply);
 259
 260     *reply = daemon_reply;
 261
 262     if ( (daemon_reply[0] == 'O') && (daemon_reply[1] == 'K') )
 263         return PWCHECK_OK;
 264
 265     if ( (daemon_reply[0] == 'N') && (daemon_reply[1] == 'O') )
 266         return PWCHECK_NO;
 267
 268     return PWCHECK_FAIL;
 269 }
 270
 271 #endif
 272
 273
 274 /* helper functions */
 275 #if defined(CYRUS_PWCHECK_SOCKET) || defined(CYRUS_SASLAUTHD_SOCKET)
 276
 277 #define MAX_REQ_LEN 1024
 278
 279 /* written from scratch */
 280
 281 /* FUNCTION: read_string */
 282
 283 /* SYNOPSIS
 284  * read a sasld-style counted string into
 285  * store-allocated buffer, set pointer to the buffer,
 286  * return number of bytes read or -1 on failure.
 287  * END SYNOPSIS */
 288
 289 static int read_string(int fd, uschar **retval) {
 290     unsigned short count;
 291     int rc;
 292
 293     rc = (retry_read(fd, &count, sizeof(count)) < (int) sizeof(count));
 294     if (!rc) {
 295         count = ntohs(count);
 296         if (count > MAX_REQ_LEN) {
 297             return -1;
 298         } else {
 299             *retval = store_get(count + 1);
 300             rc = (retry_read(fd, *retval, count) < (int) count);
 301             (*retval)[count] = '\0';
 302             return count;
 303         }
 304     }
 305     return -1;
 306 }
 307
 308
 309 /* FUNCTION: write_string */
 310
 311 /* SYNOPSIS
 312  * write a sasld-style counted string into given fd
 313  * written bytes on success, -1 on failure.
 314  * END SYNOPSIS */
 315
 316 static int write_string(int fd, const uschar *string, int len) {
 317     unsigned short count;
 318     int rc;
 319     struct iovec iov[2];
 320
 321     count = htons(len);
 322
 323     iov[0].iov_base = (void *) &count;
 324     iov[0].iov_len = sizeof(count);
 325     iov[1].iov_base = (void *) string;
 326     iov[1].iov_len = len;
 327
 328     rc = retry_writev(fd, iov, 2);
 329
 330     return rc;
 331 }
 332
 333
 334 /* taken from cyrus-sasl file saslauthd/saslauthd-unix.c  */
 335
 336 /* FUNCTION: retry_read */
 337
 338 /* SYNOPSIS
 339  * Keep calling the read() system call with 'fd', 'buf', and 'nbyte'
 340  * until all the data is read in or an error occurs.
 341  * END SYNOPSIS */
 342 static int retry_read(int fd, void *inbuf, unsigned nbyte)
 343 {
 344     int n;
 345     int nread = 0;
 346     char *buf = (char *)inbuf;
 347
 348     if (nbyte == 0) return 0;
 349
 350     for (;;) {
 351        n = read(fd, buf, nbyte);
 352        if (n == 0) {
 353            /* end of file */
 354            return -1;
 355        }
 356        if (n == -1) {
 357            if (errno == EINTR) continue;
 358            return -1;
 359        }
 360
 361        nread += n;
 362
 363        if (n >= (int) nbyte) return nread;
 364
 365        buf += n;
 366        nbyte -= n;
 367     }
 368 }
 369
 370 /* END FUNCTION: retry_read */
 371
 372 /* FUNCTION: retry_writev */
 373
 374 /* SYNOPSIS
 375  * Keep calling the writev() system call with 'fd', 'iov', and 'iovcnt'
 376  * until all the data is written out or an error occurs.
 377  * END SYNOPSIS */
 378
 379 static int     /* R: bytes written, or -1 on error */
 380 retry_writev (
 381   /* PARAMETERS */
 382   int fd,                              /* I: fd to write on */
 383   struct iovec *iov,                   /* U: iovec array base
 384                                         *    modified as data written */
 385   int iovcnt                           /* I: number of iovec entries */
 386   /* END PARAMETERS */
 387   )
 388 {
 389     /* VARIABLES */
 390     int n;                             /* return value from writev() */
 391     int i;                             /* loop counter */
 392     int written;                       /* bytes written so far */
 393     static int iov_max;                        /* max number of iovec entries */
 394     /* END VARIABLES */
 395
 396     /* initialization */
 397 #ifdef MAXIOV
 398     iov_max = MAXIOV;
 399 #else /* ! MAXIOV */
 400 # ifdef IOV_MAX
 401     iov_max = IOV_MAX;
 402 # else /* ! IOV_MAX */
 403     iov_max = 8192;
 404 # endif /* ! IOV_MAX */
 405 #endif /* ! MAXIOV */
 406     written = 0;
 407
 408     for (;;) {
 409
 410        while (iovcnt && iov[0].iov_len == 0) {
 411            iov++;
 412            iovcnt--;
 413        }
 414
 415        if (!iovcnt) {
 416            return written;
 417        }
 418
 419        n = writev(fd, iov, iovcnt > iov_max ? iov_max : iovcnt);
 420        if (n == -1) {
 421            if (errno == EINVAL && iov_max > 10) {
 422                iov_max /= 2;
 423                continue;
 424            }
 425            if (errno == EINTR) {
 426                continue;
 427            }
 428            return -1;
 429        } else {
 430            written += n;
 431        }
 432
 433        for (i = 0; i < iovcnt; i++) {
 434            if (iov[i].iov_len > (unsigned) n) {
 435                iov[i].iov_base = (char *)iov[i].iov_base + n;
 436                iov[i].iov_len -= n;
 437                break;
 438            }
 439            n -= iov[i].iov_len;
 440            iov[i].iov_len = 0;
 441        }
 442
 443        if (i == iovcnt) {
 444            return written;
 445        }
 446     }
 447     /* NOTREACHED */
 448 }
 449
 450 /* END FUNCTION: retry_writev */
 451 #endif
 452
 453 /* End of auths/pwcheck.c */