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