src/pam/afs_auth.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 #include <afsconfig.h>
  11 #include <afs/param.h>
  12
  13 #include <roken.h>
  14
  15 #ifdef HAVE_SYS_WAIT_H
  16 #include <sys/wait.h>
  17 #endif
  18
  19 #include <afs/sys_prototypes.h>
  20 #include <afs/kautils.h>
  21
  22 #include <security/pam_appl.h>
  23 #include <security/pam_modules.h>
  24
  25 #include "afs_message.h"
  26 #include "afs_pam_msg.h"
  27 #include "afs_util.h"
  28
  29 #define RET(x) { retcode = (x); goto out; }
  30
  31 extern int
  32 pam_sm_authenticate(pam_handle_t * pamh, int flags, int argc,
  33                     const char **argv)
  34 {
  35     int retcode = PAM_SUCCESS;
  36     int errcode = PAM_SUCCESS;
  37     int code;
  38     int origmask;
  39     int logmask = LOG_UPTO(LOG_INFO);
  40     int nowarn = 0;
  41     int use_first_pass = 0;
  42     int try_first_pass = 0;
  43     int ignore_uid = 0;
  44     uid_t ignore_uid_id = 0;
  45     char my_password_buf[256];
  46     char *cell_ptr = NULL;
  47     /*
  48      * these options are added to handle stupid apps, which won't call
  49      * pam_set_cred()
  50      */
  51     int refresh_token = 0;
  52     int set_token = 0;
  53     int dont_fork = 0;
  54     /* satisfy kdm 2.x
  55      */
  56     int use_klog = 0;
  57     int got_authtok = 0;        /* got PAM_AUTHTOK upon entry */
  58     PAM_CONST char *user = NULL, *password = NULL;
  59     afs_int32 password_expires = -1;
  60     char *torch_password = NULL;
  61     int i;
  62     PAM_CONST struct pam_conv *pam_convp = NULL;
  63     int auth_ok;
  64     struct passwd *upwd = NULL;
  65     char *reason = NULL;
  66     pid_t cpid, rcpid;
  67     int status;
  68     struct sigaction newAction, origAction;
  69 #if !(defined(AFS_LINUX20_ENV) || defined(AFS_FBSD_ENV) || defined(AFS_DFBSD_ENV) || defined(AFS_NBSD_ENV))
  70     char upwd_buf[2048];       /* size is a guess. */
  71     struct passwd unix_pwd;
  72 #endif
  73
  74
  75 #ifndef AFS_SUN5_ENV
  76     openlog(pam_afs_ident, LOG_CONS | LOG_PID, LOG_AUTH);
  77 #endif
  78     origmask = setlogmask(logmask);
  79
  80     /*
  81      * Parse the user options.  Log an error for any unknown options.
  82      */
  83     for (i = 0; i < argc; i++) {
  84         if (strcasecmp(argv[i], "debug") == 0) {
  85             logmask |= LOG_MASK(LOG_DEBUG);
  86             (void)setlogmask(logmask);
  87         } else if (strcasecmp(argv[i], "nowarn") == 0) {
  88             nowarn = 1;
  89         } else if (strcasecmp(argv[i], "use_first_pass") == 0) {
  90             use_first_pass = 1;
  91         } else if (strcasecmp(argv[i], "try_first_pass") == 0) {
  92             try_first_pass = 1;
  93         } else if (strcasecmp(argv[i], "ignore_root") == 0) {
  94             ignore_uid = 1;
  95             ignore_uid_id = 0;
  96         } else if (strcasecmp(argv[i], "ignore_uid") == 0) {
  97             i++;
  98             if (i == argc) {
  99                 pam_afs_syslog(LOG_ERR, PAMAFS_IGNOREUID,
 100                                "ignore_uid missing argument");
 101                 ignore_uid = 0;
 102             } else {
 103                 ignore_uid = 1;
 104                 ignore_uid_id = (uid_t) strtol(argv[i], NULL, 10);
 105                 if (ignore_uid_id > IGNORE_MAX) {
 106                     ignore_uid = 0;
 107                     pam_afs_syslog(LOG_ERR, PAMAFS_IGNOREUID, argv[i]);
 108                 }
 109             }
 110         } else if (strcasecmp(argv[i], "cell") == 0) {
 111             i++;
 112             if (i == argc) {
 113                 pam_afs_syslog(LOG_ERR, PAMAFS_OTHERCELL,
 114                                "cell missing argument");
 115             } else {
 116                 cell_ptr = (char *)argv[i];
 117                 pam_afs_syslog(LOG_INFO, PAMAFS_OTHERCELL, cell_ptr);
 118             }
 119         } else if (strcasecmp(argv[i], "refresh_token") == 0) {
 120             refresh_token = 1;
 121         } else if (strcasecmp(argv[i], "set_token") == 0) {
 122             set_token = 1;
 123         } else if (strcasecmp(argv[i], "dont_fork") == 0) {
 124             if (!use_klog)
 125                 dont_fork = 1;
 126             else
 127                 pam_afs_syslog(LOG_ERR, PAMAFS_CONFLICTOPT, "dont_fork");
 128         } else if (strcasecmp(argv[i], "use_klog") == 0) {
 129             if (!dont_fork)
 130                 use_klog = 1;
 131             else
 132                 pam_afs_syslog(LOG_ERR, PAMAFS_CONFLICTOPT, "use_klog");
 133         } else if (strcasecmp(argv[i], "setenv_password_expires") == 0) {
 134             ;
 135         } else {
 136             pam_afs_syslog(LOG_ERR, PAMAFS_UNKNOWNOPT, argv[i]);
 137         }
 138     }
 139
 140     /* Later we use try_first_pass to see if we can try again.    */
 141     /* If use_first_pass is true we don't want to ever try again, */
 142     /* so turn that flag off right now.                           */
 143     if (use_first_pass)
 144         try_first_pass = 0;
 145
 146     if (logmask & LOG_MASK(LOG_DEBUG))
 147         pam_afs_syslog(LOG_DEBUG, PAMAFS_OPTIONS, nowarn, use_first_pass,
 148                        try_first_pass, ignore_uid, ignore_uid_id,
 149                        refresh_token, set_token, dont_fork, use_klog);
 150
 151     /* Try to get the user-interaction info, if available. */
 152     errcode = pam_get_item(pamh, PAM_CONV, (PAM_CONST void **)&pam_convp);
 153     if (errcode != PAM_SUCCESS) {
 154         pam_afs_syslog(LOG_WARNING, PAMAFS_NO_USER_INT);
 155         pam_convp = NULL;
 156     }
 157
 158     /* Who are we trying to authenticate here? */
 159     if ((errcode =
 160          pam_get_user(pamh, &user,
 161                       "login: ")) != PAM_SUCCESS) {
 162         pam_afs_syslog(LOG_ERR, PAMAFS_NOUSER, errcode);
 163         RET(PAM_USER_UNKNOWN);
 164     }
 165
 166     if (logmask & LOG_MASK(LOG_DEBUG))
 167         pam_afs_syslog(LOG_DEBUG, PAMAFS_USERNAMEDEBUG, user);
 168
 169     /*
 170      * If the user has a "local" (or via nss, possibly nss_dce) pwent,
 171      * and its uid==0, and "ignore_root" was given in pam.conf,
 172      * ignore the user.
 173      */
 174     /* enhanced: use "ignore_uid <number>" to specify the largest uid
 175      * which should be ignored by this module
 176      */
 177 #if     defined(AFS_HPUX_ENV) || defined(AFS_DARWIN100_ENV) || defined(AFS_SUN5_ENV)
 178 #if     defined(AFS_HPUX110_ENV) || defined(AFS_DARWIN100_ENV) || defined(AFS_SUN5_ENV)
 179     i = getpwnam_r(user, &unix_pwd, upwd_buf, sizeof(upwd_buf), &upwd);
 180 #else /* AFS_HPUX110_ENV */
 181     i = getpwnam_r(user, &unix_pwd, upwd_buf, sizeof(upwd_buf));
 182     if (i == 0)                 /* getpwnam_r success */
 183         upwd = &unix_pwd;
 184 #endif /* else AFS_HPUX110_ENV */
 185     if (ignore_uid && i == 0 && upwd && upwd->pw_uid <= ignore_uid_id) {
 186         pam_afs_syslog(LOG_INFO, PAMAFS_IGNORINGROOT, user);
 187         RET(PAM_AUTH_ERR);
 188     }
 189 #else
 190 #if     defined(AFS_LINUX20_ENV) || defined(AFS_FBSD_ENV) || defined(AFS_DFBSD_ENV) || defined(AFS_NBSD_ENV)
 191     upwd = getpwnam(user);
 192 #else
 193     upwd = getpwnam_r(user, &unix_pwd, upwd_buf, sizeof(upwd_buf));
 194 #endif
 195     if (ignore_uid && upwd != NULL && upwd->pw_uid <= ignore_uid_id) {
 196         pam_afs_syslog(LOG_INFO, PAMAFS_IGNORINGROOT, user);
 197         RET(PAM_AUTH_ERR);
 198     }
 199 #endif
 200     errcode = pam_get_item(pamh, PAM_AUTHTOK, (PAM_CONST void **)&password);
 201     if (errcode != PAM_SUCCESS || password == NULL) {
 202         if (use_first_pass) {
 203             pam_afs_syslog(LOG_ERR, PAMAFS_PASSWD_REQ, user);
 204             RET(PAM_AUTH_ERR);
 205         }
 206         password = NULL;        /* In case it isn't already NULL */
 207         if (logmask & LOG_MASK(LOG_DEBUG))
 208             pam_afs_syslog(LOG_DEBUG, PAMAFS_NOFIRSTPASS, user);
 209     } else if (password[0] == '\0') {
 210         /* Actually we *did* get one but it was empty. */
 211         pam_afs_syslog(LOG_INFO, PAMAFS_NILPASSWORD, user);
 212         RET(PAM_NEW_AUTHTOK_REQD);
 213     } else {
 214         if (logmask & LOG_MASK(LOG_DEBUG))
 215             pam_afs_syslog(LOG_DEBUG, PAMAFS_GOTPASS, user);
 216         got_authtok = 1;
 217     }
 218     if (!(use_first_pass || try_first_pass)) {
 219         password = NULL;
 220     }
 221
 222   try_auth:
 223     if (password == NULL) {
 224         char *prompt_password;
 225
 226         if (use_first_pass)
 227             RET(PAM_AUTH_ERR);  /* shouldn't happen */
 228         if (try_first_pass)
 229             try_first_pass = 0; /* we come back if try_first_pass==1 below */
 230
 231         if (pam_convp == NULL || pam_convp->conv == NULL) {
 232             pam_afs_syslog(LOG_ERR, PAMAFS_CANNOT_PROMPT);
 233             RET(PAM_AUTH_ERR);
 234         }
 235
 236         errcode = pam_afs_prompt(pam_convp, &prompt_password, 0, PAMAFS_PWD_PROMPT);
 237         if (errcode != PAM_SUCCESS || prompt_password == NULL) {
 238             pam_afs_syslog(LOG_ERR, PAMAFS_GETPASS_FAILED);
 239             RET(PAM_AUTH_ERR);
 240         }
 241         if (prompt_password[0] == '\0') {
 242             pam_afs_syslog(LOG_INFO, PAMAFS_NILPASSWORD, user);
 243             RET(PAM_NEW_AUTHTOK_REQD);
 244         }
 245
 246         /*
 247          * We aren't going to free the password later (we will wipe it,
 248          * though), because the storage for it if we get it from other
 249          * paths may belong to someone else.  Since we do need to free
 250          * this storage, copy it to a buffer that won't need to be freed
 251          * later, and free this storage now.
 252          */
 253
 254         strncpy(my_password_buf, prompt_password, sizeof(my_password_buf));
 255         my_password_buf[sizeof(my_password_buf) - 1] = '\0';
 256         memset(prompt_password, 0, strlen(prompt_password));
 257         free(prompt_password);
 258         password = torch_password = my_password_buf;
 259
 260     }
 261
 262     /* Be sure to allocate a PAG here if we should set a token,
 263      * All of the remaining stuff to authenticate the user and to
 264      * get a token is done in a child process - if not suppressed by the config,
 265      * see below
 266      * But dont get a PAG if the refresh_token option was set
 267      * We have to do this in such a way because some
 268      * apps (such as screensavers) wont call setcred but authenticate :-(
 269      */
 270     if (!refresh_token) {
 271         setpag();
 272 #ifdef AFS_KERBEROS_ENV
 273         ktc_newpag();
 274 #endif
 275         if (logmask & LOG_MASK(LOG_DEBUG))
 276             syslog(LOG_DEBUG, "New PAG created in pam_authenticate()");
 277     }
 278
 279     if (!dont_fork) {
 280         /* Prepare for fork(): set SIGCHLD signal handler to default */
 281         sigemptyset(&newAction.sa_mask);
 282         newAction.sa_handler = SIG_DFL;
 283         newAction.sa_flags = 0;
 284         code = sigaction(SIGCHLD, &newAction, &origAction);
 285         if (code) {
 286             pam_afs_syslog(LOG_ERR, PAMAFS_PAMERROR, errno);
 287             RET(PAM_AUTH_ERR);
 288         }
 289
 290         /* Fork a process and let it verify authentication. So that any
 291          * memory/sockets allocated will get cleaned up when the child
 292          * exits: defect 11686.
 293          */
 294         if (use_klog) {         /* used by kdm 2.x */
 295             if (refresh_token || set_token) {
 296                 i = do_klog(user, password, NULL, cell_ptr);
 297             } else {
 298                 i = do_klog(user, password, "00:00:01", cell_ptr);
 299                 ktc_ForgetAllTokens();
 300             }
 301             if (logmask & LOG_MASK(LOG_DEBUG))
 302                 syslog(LOG_DEBUG, "do_klog returned %d", i);
 303             auth_ok = i ? 0 : 1;
 304         } else {
 305             if (logmask & LOG_MASK(LOG_DEBUG))
 306                 syslog(LOG_DEBUG, "forking ...");
 307             cpid = fork();
 308             if (cpid <= 0) {    /* The child process */
 309                 if (logmask & LOG_MASK(LOG_DEBUG))
 310                     syslog(LOG_DEBUG, "in child");
 311                 if (refresh_token || set_token)
 312                     code = ka_UserAuthenticateGeneral(KA_USERAUTH_VERSION, (char *)user,        /* kerberos name */
 313                                                       NULL,     /* instance */
 314                                                       cell_ptr, /* realm */
 315                                                       (char *)password, /* password */
 316                                                       0,        /* default lifetime */
 317                                                       &password_expires, 0,     /* spare 2 */
 318                                                       &reason
 319                                                       /* error string */ );
 320                 else
 321                     code = ka_VerifyUserPassword(KA_USERAUTH_VERSION, (char *)user,     /* kerberos name */
 322                                                  NULL,  /* instance */
 323                                                  cell_ptr,      /* realm */
 324                                                  (char *)password,      /* password */
 325                                                  0,     /* spare 2 */
 326                                                  &reason /* error string */ );
 327                 if (code) {
 328                     pam_afs_syslog(LOG_ERR, PAMAFS_LOGIN_FAILED, user,
 329                                    reason);
 330                     auth_ok = 0;
 331                 } else {
 332                     auth_ok = 1;
 333                 }
 334                 if (logmask & LOG_MASK(LOG_DEBUG))
 335                     syslog(LOG_DEBUG, "child: auth_ok=%d", auth_ok);
 336                 if (cpid == 0)
 337                     exit(auth_ok);
 338             } else {
 339                 do {
 340                     if (logmask & LOG_MASK(LOG_DEBUG))
 341                         syslog(LOG_DEBUG, "in parent, waiting ...");
 342                     rcpid = waitpid(cpid, &status, 0);
 343                 } while ((rcpid == -1) && (errno == EINTR));
 344
 345                 if ((rcpid == cpid) && WIFEXITED(status)) {
 346                     auth_ok = WEXITSTATUS(status);
 347                 } else {
 348                     auth_ok = 0;
 349                 }
 350                 if (logmask & LOG_MASK(LOG_DEBUG))
 351                     syslog(LOG_DEBUG, "parent: auth_ok=%d", auth_ok);
 352             }
 353         }
 354         /* Restore old signal handler */
 355         code = sigaction(SIGCHLD, &origAction, NULL);
 356         if (code) {
 357             pam_afs_syslog(LOG_ERR, PAMAFS_PAMERROR, errno);
 358         }
 359     } else {                    /* dont_fork, used by httpd */
 360         if (logmask & LOG_MASK(LOG_DEBUG))
 361             syslog(LOG_DEBUG, "dont_fork");
 362         if (refresh_token || set_token)
 363             code = ka_UserAuthenticateGeneral(KA_USERAUTH_VERSION, (char *)user,        /* kerberos name */
 364                                               NULL,     /* instance */
 365                                               cell_ptr, /* realm */
 366                                               (char *)password, /* password */
 367                                               0,        /* default lifetime */
 368                                               &password_expires, 0,     /* spare 2 */
 369                                               &reason /* error string */ );
 370         else
 371             code = ka_VerifyUserPassword(KA_USERAUTH_VERSION, (char *)user,     /* kerberos name */
 372                                          NULL,  /* instance */
 373                                          cell_ptr,      /* realm */
 374                                          (char *)password,      /* password */
 375                                          0,     /* spare 2 */
 376                                          &reason /* error string */ );
 377         if (logmask & LOG_MASK(LOG_DEBUG))
 378             syslog(LOG_DEBUG, "dont_fork, code = %d", code);
 379         if (code) {
 380             pam_afs_syslog(LOG_ERR, PAMAFS_LOGIN_FAILED, user, reason);
 381             auth_ok = 0;
 382         } else {
 383             auth_ok = 1;
 384         }
 385         if (logmask & LOG_MASK(LOG_DEBUG))
 386             syslog(LOG_DEBUG, "dont_fork: auth_ok=%d", auth_ok);
 387     }
 388
 389     if (!auth_ok && try_first_pass) {
 390         password = NULL;
 391         goto try_auth;
 392     }
 393
 394     /* We don't care if this fails; all we can do is try. */
 395     /* It is not reasonable to store the password only if it was correct
 396      * because it could satisfy another module that is called in the chain
 397      * after pam_afs
 398      */
 399     if (!got_authtok) {
 400         torch_password = NULL;
 401         (void)pam_set_item(pamh, PAM_AUTHTOK, password);
 402     }
 403
 404     if (logmask & LOG_MASK(LOG_DEBUG))
 405         syslog(LOG_DEBUG, "leaving auth: auth_ok=%d", auth_ok);
 406     if (code == KANOENT)
 407         RET(PAM_USER_UNKNOWN);
 408     RET(auth_ok ? PAM_SUCCESS : PAM_AUTH_ERR);
 409
 410   out:
 411     if (password) {
 412         /* we store the password in the data portion */
 413         char *tmp = strdup(password);
 414         (void)pam_set_data(pamh, pam_afs_lh, tmp, lc_cleanup);
 415         if (torch_password)
 416             memset(torch_password, 0, strlen(torch_password));
 417     }
 418     (void)setlogmask(origmask);
 419 #ifndef AFS_SUN5_ENV
 420     closelog();
 421 #endif
 422     return retcode;
 423 }