237 lines
6.8 KiB
C
237 lines
6.8 KiB
C
/*
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* pam_umask module
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*
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* Copyright (c) 2005, 2006, 2007, 2010, 2013 Thorsten Kukuk <kukuk@thkukuk.de>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, and the entire permission notice in its entirety,
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* including the disclaimer of warranties.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* ALTERNATIVELY, this product may be distributed under the terms of
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* the GNU Public License V2, in which case the provisions of the GPL
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* are required INSTEAD OF the above restrictions. (This clause is
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* necessary due to a potential bad interaction between the GPL and
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* the restrictions contained in a BSD-style copyright.)
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "config.h"
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#include <pwd.h>
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#include <grp.h>
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#include <stdio.h>
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#include <string.h>
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#include <stdarg.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/resource.h>
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#include <syslog.h>
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#include <security/pam_modules.h>
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#include <security/pam_modutil.h>
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#include <security/pam_ext.h>
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#include "pam_inline.h"
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#define LOGIN_DEFS "/etc/login.defs"
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#define LOGIN_CONF "/etc/default/login"
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struct options_t {
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int debug;
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int usergroups;
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int silent;
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const char *umask;
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char *login_umask;
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};
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typedef struct options_t options_t;
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static void
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parse_option (const pam_handle_t *pamh, const char *argv, options_t *options)
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{
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const char *str;
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if (argv == NULL || argv[0] == '\0')
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return;
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if (strcasecmp (argv, "debug") == 0)
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options->debug = 1;
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else if ((str = pam_str_skip_icase_prefix (argv, "umask=")) != NULL)
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options->umask = str;
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else if (strcasecmp (argv, "usergroups") == 0)
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options->usergroups = 1;
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else if (strcasecmp (argv, "nousergroups") == 0)
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options->usergroups = 0;
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else if (strcasecmp (argv, "silent") == 0)
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options->silent = 1;
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else
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pam_syslog (pamh, LOG_ERR, "Unknown option: `%s'", argv);
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}
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static int
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get_options (pam_handle_t *pamh, options_t *options,
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int argc, const char **argv)
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{
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memset (options, 0, sizeof (options_t));
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options->usergroups = DEFAULT_USERGROUPS_SETTING;
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/* Parse parameters for module */
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for ( ; argc-- > 0; argv++)
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parse_option (pamh, *argv, options);
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if (options->umask == NULL) {
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options->login_umask = pam_modutil_search_key (pamh, LOGIN_DEFS, "UMASK");
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if (options->login_umask == NULL)
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options->login_umask = pam_modutil_search_key (pamh, LOGIN_CONF, "UMASK");
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options->umask = options->login_umask;
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}
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return 0;
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}
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static void
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set_umask (const char *value)
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{
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const char *value_orig = value;
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mode_t mask;
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char *endptr;
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mask = strtoul (value, &endptr, 8) & 0777;
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if (((mask == 0) && (value_orig == endptr)) ||
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((mask == UINT_MAX) && (errno == ERANGE)))
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return;
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umask (mask);
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}
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/* Set the process nice, ulimit, and umask from the
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password file entry. */
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static void
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setup_limits_from_gecos (pam_handle_t *pamh, options_t *options,
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struct passwd *pw)
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{
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char *cp;
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if (options->usergroups)
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{
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/* if not root and username is the same as primary group name,
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set umask group bits to be the same as owner bits
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(examples: 022 -> 002, 077 -> 007). */
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if (pw->pw_uid != 0)
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{
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struct group *grp = pam_modutil_getgrgid (pamh, pw->pw_gid);
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if (grp && (strcmp (pw->pw_name, grp->gr_name) == 0))
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{
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mode_t oldmask = umask (0777);
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umask ((oldmask & ~070) | ((oldmask >> 3) & 070));
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}
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}
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}
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/* See if the GECOS field contains values for NICE, UMASK or ULIMIT. */
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for (cp = pw->pw_gecos; cp != NULL; cp = strchr (cp, ','))
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{
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const char *str;
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if (*cp == ',')
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cp++;
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if ((str = pam_str_skip_icase_prefix (cp, "umask=")) != NULL)
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umask (strtol (str, NULL, 8) & 0777);
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else if ((str = pam_str_skip_icase_prefix (cp, "pri=")) != NULL)
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{
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errno = 0;
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if (nice (strtol (str, NULL, 10)) == -1 && errno != 0)
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{
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if (!options->silent || options->debug)
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pam_error (pamh, "nice failed: %m\n");
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pam_syslog (pamh, LOG_ERR, "nice failed: %m");
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}
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}
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else if ((str = pam_str_skip_icase_prefix (cp, "ulimit=")) != NULL)
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{
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struct rlimit rlimit_fsize;
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rlimit_fsize.rlim_cur = 512L * strtol (str, NULL, 10);
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rlimit_fsize.rlim_max = rlimit_fsize.rlim_cur;
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if (setrlimit (RLIMIT_FSIZE, &rlimit_fsize) == -1)
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{
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if (!options->silent || options->debug)
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pam_error (pamh, "setrlimit failed: %m\n");
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pam_syslog (pamh, LOG_ERR, "setrlimit failed: %m");
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}
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}
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}
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}
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int
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pam_sm_open_session (pam_handle_t *pamh, int flags UNUSED,
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int argc, const char **argv)
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{
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struct passwd *pw;
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options_t options;
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const char *name;
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int retval = PAM_SUCCESS;
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get_options (pamh, &options, argc, argv);
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if (flags & PAM_SILENT)
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options.silent = 1;
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/* get the user name. */
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if ((retval = pam_get_user (pamh, &name, NULL)) != PAM_SUCCESS)
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{
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pam_syslog(pamh, LOG_NOTICE, "cannot determine user name: %s",
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pam_strerror(pamh, retval));
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return (retval == PAM_CONV_AGAIN ? PAM_INCOMPLETE:retval);
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}
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pw = pam_modutil_getpwnam (pamh, name);
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if (pw == NULL)
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{
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pam_syslog (pamh, LOG_NOTICE, "account for %s not found", name);
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return PAM_USER_UNKNOWN;
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}
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if (options.umask != NULL)
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{
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set_umask (options.umask);
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free (options.login_umask);
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options.umask = options.login_umask = NULL;
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}
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setup_limits_from_gecos (pamh, &options, pw);
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return retval;
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}
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int
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pam_sm_close_session (pam_handle_t *pamh UNUSED, int flags UNUSED,
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int argc UNUSED, const char **argv UNUSED)
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{
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return PAM_SUCCESS;
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}
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/* end of module definition */
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