freebsd-dev/contrib/libpam/modules/pam_limits/pam_limits.c

593 lines
18 KiB
C

/*
* pam_limits - impose resource limits when opening a user session
*
* 1.5 - Elliot Lee's "max system logins patch"
* 1.4 - addressed bug in configuration file parser
* 1.3 - modified the configuration file format
* 1.2 - added 'debug' and 'conf=' arguments
* 1.1 - added @group support
* 1.0 - initial release - Linux ONLY
*
* See end for Copyright information
*/
#if !(defined(linux))
#error THIS CODE IS KNOWN TO WORK ONLY ON LINUX !!!
#endif
#include <stdio.h>
#include <unistd.h>
#define __USE_POSIX2
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <syslog.h>
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/resource.h>
#include <utmp.h>
#ifndef UT_USER /* some systems have ut_name instead of ut_user */
#define UT_USER ut_user
#endif
/* Module defines */
#define LINE_LENGTH 1024
#define LIMITS_DEF_USER 0 /* limit was set by an user entry */
#define LIMITS_DEF_GROUP 1 /* limit was set by a group entry */
#define LIMITS_DEF_DEFAULT 2 /* limit was set by an default entry */
#define LIMITS_DEF_NONE 3 /* this limit was not set yet */
/* internal data */
static char conf_file[BUFSIZ];
struct user_limits_struct {
int src_soft;
int src_hard;
struct rlimit limit;
};
static struct user_limits_struct limits[RLIM_NLIMITS];
static int login_limit; /* the max logins limit */
static int login_limit_def; /* which entry set the login limit */
static int flag_numsyslogins; /* whether to limit logins only for a
specific user or to count all logins */
#define LIMIT_LOGIN RLIM_NLIMITS+1
#define LIMIT_NUMSYSLOGINS RLIM_NLIMITS+2
#define LIMIT_SOFT 1
#define LIMIT_HARD 2
#define PAM_SM_SESSION
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <pwdb/pwdb_map.h>
/* logging */
static void _pam_log(int err, const char *format, ...)
{
va_list args;
va_start(args, format);
openlog("pam_limits", LOG_CONS|LOG_PID, LOG_AUTH);
vsyslog(err, format, args);
va_end(args);
closelog();
}
/* argument parsing */
#define PAM_DEBUG_ARG 0x0001
static int _pam_parse(int argc, const char **argv)
{
int ctrl=0;
/* step through arguments */
for (ctrl=0; argc-- > 0; ++argv) {
/* generic options */
if (!strcmp(*argv,"debug"))
ctrl |= PAM_DEBUG_ARG;
else if (!strncmp(*argv,"conf=",5))
strcpy(conf_file,*argv+5);
else {
_pam_log(LOG_ERR,"pam_parse: unknown option; %s",*argv);
}
}
return ctrl;
}
/* limits stuff */
#ifndef LIMITS_FILE
#define LIMITS_FILE "/etc/security/limits.conf"
#endif
#define LIMIT_ERR 1 /* error setting a limit */
#define LOGIN_ERR 2 /* too many logins err */
/* Counts the number of user logins and check against the limit*/
static int check_logins(const char *name, int limit, int ctrl)
{
struct utmp *ut;
unsigned int count;
if (ctrl & PAM_DEBUG_ARG) {
_pam_log(LOG_DEBUG, "checking logins for '%s' / %d\n", name,limit);
}
if (limit < 0)
return 0; /* no limits imposed */
if (limit == 0) /* maximum 0 logins ? */ {
_pam_log(LOG_WARNING, "No logins allowed for '%s'\n", name);
return LOGIN_ERR;
}
setutent();
count = 0;
while((ut = getutent())) {
#ifdef USER_PROCESS
if (ut->ut_type != USER_PROCESS)
continue;
#endif
if (ut->UT_USER[0] == '\0')
continue;
if (!flag_numsyslogins
&& strncmp(name, ut->UT_USER, sizeof(ut->UT_USER)) != 0)
continue;
if (++count >= limit)
break;
}
endutent();
if (count >= limit) {
if (name) {
_pam_log(LOG_WARNING, "Too many logins (max %d) for %s",
limit, name);
} else {
_pam_log(LOG_WARNING, "Too many system logins (max %d)", limit);
}
return LOGIN_ERR;
}
return 0;
}
/* checks if a user is on a list of members of the GID 0 group */
static int is_on_list(char * const *list, const char *member)
{
while (*list) {
if (strcmp(*list, member) == 0)
return 1;
list++;
}
return 0;
}
/* Checks if a user is a member of a group */
static int is_on_group(const char *user_name, const char *group_name)
{
struct passwd *pwd;
struct group *grp, *pgrp;
char uname[LINE_LENGTH], gname[LINE_LENGTH];
if (!strlen(user_name))
return 0;
if (!strlen(group_name))
return 0;
memset(uname, 0, sizeof(uname));
strncpy(uname, user_name, LINE_LENGTH);
memset(gname, 0, sizeof(gname));
strncpy(gname, group_name, LINE_LENGTH);
setpwent();
pwd = getpwnam(uname);
endpwent();
if (!pwd)
return 0;
/* the info about this group */
setgrent();
grp = getgrnam(gname);
endgrent();
if (!grp)
return 0;
/* first check: is a member of the group_name group ? */
if (is_on_list(grp->gr_mem, uname))
return 1;
/* next check: user primary group is group_name ? */
setgrent();
pgrp = getgrgid(pwd->pw_gid);
endgrent();
if (!pgrp)
return 0;
if (!strcmp(pgrp->gr_name, gname))
return 1;
return 0;
}
static int init_limits(void)
{
int retval = PAM_SUCCESS;
D(("called."));
retval |= getrlimit(RLIMIT_CPU, &limits[RLIMIT_CPU].limit);
limits[RLIMIT_CPU].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_CPU].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_FSIZE, &limits[RLIMIT_FSIZE].limit);
limits[RLIMIT_FSIZE].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_FSIZE].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_DATA, &limits[RLIMIT_DATA].limit);
limits[RLIMIT_DATA].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_DATA].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_STACK, &limits[RLIMIT_STACK].limit);
limits[RLIMIT_STACK].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_STACK].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_CORE, &limits[RLIMIT_CORE].limit);
limits[RLIMIT_CORE].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_CORE].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_RSS, &limits[RLIMIT_RSS].limit);
limits[RLIMIT_RSS].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_RSS].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_NPROC, &limits[RLIMIT_NPROC].limit);
limits[RLIMIT_NPROC].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_NPROC].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_NOFILE, &limits[RLIMIT_NOFILE].limit);
limits[RLIMIT_NOFILE].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_NOFILE].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_MEMLOCK, &limits[RLIMIT_MEMLOCK].limit);
limits[RLIMIT_MEMLOCK].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_MEMLOCK].src_hard = LIMITS_DEF_NONE;
retval |= getrlimit(RLIMIT_AS, &limits[RLIMIT_AS].limit);
limits[RLIMIT_AS].src_soft = LIMITS_DEF_NONE;
limits[RLIMIT_AS].src_hard = LIMITS_DEF_NONE;
login_limit = -2;
login_limit_def = LIMITS_DEF_NONE;
return retval;
}
static void process_limit(int source, const char *lim_type,
const char *lim_item, const char *lim_value,
int ctrl)
{
int limit_item;
int limit_type = 0;
long limit_value;
char **endptr = (char **) &lim_value;
const char *value_orig = lim_value;
if (ctrl & PAM_DEBUG_ARG)
_pam_log(LOG_DEBUG, "%s: processing(%d) %s %s %s\n",
__FUNCTION__,source,lim_type,lim_item,lim_value);
if (strcmp(lim_item, "cpu") == 0)
limit_item = RLIMIT_CPU;
else if (strcmp(lim_item, "fsize") == 0)
limit_item = RLIMIT_FSIZE;
else if (strcmp(lim_item, "data") == 0)
limit_item = RLIMIT_DATA;
else if (strcmp(lim_item, "stack") == 0)
limit_item = RLIMIT_STACK;
else if (strcmp(lim_item, "core") == 0)
limit_item = RLIMIT_CORE;
else if (strcmp(lim_item, "rss") == 0)
limit_item = RLIMIT_RSS;
else if (strcmp(lim_item, "nproc") == 0)
limit_item = RLIMIT_NPROC;
else if (strcmp(lim_item, "nofile") == 0)
limit_item = RLIMIT_NOFILE;
else if (strcmp(lim_item, "memlock") == 0)
limit_item = RLIMIT_MEMLOCK;
else if (strcmp(lim_item, "as") == 0)
limit_item = RLIMIT_AS;
else if (strcmp(lim_item, "maxlogins") == 0) {
limit_item = LIMIT_LOGIN;
flag_numsyslogins = 0;
} else if (strcmp(lim_item, "maxsyslogins") == 0) {
limit_item = LIMIT_NUMSYSLOGINS;
flag_numsyslogins = 1;
} else {
_pam_log(LOG_DEBUG,"unknown limit item '%s'", lim_item);
return;
}
if (strcmp(lim_type,"soft")==0)
limit_type=LIMIT_SOFT;
else if (strcmp(lim_type, "hard")==0)
limit_type=LIMIT_HARD;
else if (strcmp(lim_type,"-")==0)
limit_type=LIMIT_SOFT | LIMIT_HARD;
else if (limit_item != LIMIT_LOGIN && limit_item != LIMIT_NUMSYSLOGINS) {
_pam_log(LOG_DEBUG,"unknown limit type '%s'", lim_type);
return;
}
limit_value = strtol(lim_value, endptr, 10);
if (limit_value == 0 && value_orig == *endptr) { /* no chars read */
if (strcmp(lim_value,"-") != 0) {
_pam_log(LOG_DEBUG,"wrong limit value '%s'", lim_value);
return;
} else
if (limit_item != LIMIT_LOGIN) {
if (ctrl & PAM_DEBUG_ARG)
_pam_log(LOG_DEBUG,
"'-' limit value valid for maxlogins type only");
return;
} else
limit_value = -1;
}
switch(limit_item) {
case RLIMIT_CPU:
limit_value *= 60;
break;
case RLIMIT_FSIZE:
case RLIMIT_DATA:
case RLIMIT_STACK:
case RLIMIT_CORE:
case RLIMIT_RSS:
case RLIMIT_MEMLOCK:
case RLIMIT_AS:
limit_value *= 1024;
break;
}
if (limit_item != LIMIT_LOGIN && limit_item != LIMIT_NUMSYSLOGINS) {
if (limit_type & LIMIT_SOFT)
if (limits[limit_item].src_soft < source)
return;
else {
limits[limit_item].limit.rlim_cur = limit_value;
limits[limit_item].src_soft = source;
}
if (limit_type & LIMIT_HARD)
if (limits[limit_item].src_hard < source)
return;
else {
limits[limit_item].limit.rlim_max = limit_value;
limits[limit_item].src_hard = source;
}
} else
if (login_limit_def < source)
return;
else {
login_limit = limit_value;
login_limit_def = source;
}
return;
}
static int parse_config_file(const char *uname, int ctrl)
{
FILE *fil;
char buf[LINE_LENGTH];
#define CONF_FILE (conf_file[0])?conf_file:LIMITS_FILE
/* check for the LIMITS_FILE */
if (ctrl & PAM_DEBUG_ARG)
_pam_log(LOG_DEBUG,"reading settings from '%s'", CONF_FILE);
fil = fopen(CONF_FILE, "r");
if (fil == NULL) {
_pam_log (LOG_WARNING, "can not read settings from %s", CONF_FILE);
return PAM_SERVICE_ERR;
}
#undef CONF_FILE
/* init things */
memset(buf, 0, sizeof(buf));
/* start the show */
while (fgets(buf, LINE_LENGTH, fil) != NULL) {
char domain[LINE_LENGTH];
char ltype[LINE_LENGTH];
char item[LINE_LENGTH];
char value[LINE_LENGTH];
int i,j;
char *tptr;
tptr = buf;
/* skip the leading white space */
while (*tptr && isspace(*tptr))
tptr++;
strcpy(buf, (const char *)tptr);
/* Rip off the comments */
tptr = strchr(buf,'#');
if (tptr)
*tptr = '\0';
/* Rip off the newline char */
tptr = strchr(buf,'\n');
if (tptr)
*tptr = '\0';
/* Anything left ? */
if (!strlen(buf)) {
memset(buf, 0, sizeof(buf));
continue;
}
memset(domain, 0, sizeof(domain));
memset(ltype, 0, sizeof(ltype));
memset(item, 0, sizeof(item));
memset(value, 0, sizeof(value));
i = sscanf(buf,"%s%s%s%s", domain, ltype, item, value);
for(j=0; j < strlen(domain); j++)
domain[j]=tolower(domain[j]);
for(j=0; j < strlen(ltype); j++)
ltype[j]=tolower(ltype[j]);
for(j=0; j < strlen(item); j++)
item[j]=tolower(item[j]);
for(j=0; j < strlen(value); j++)
value[j]=tolower(value[j]);
if (i == 4) { /* a complete line */
if (strcmp(uname, domain) == 0) /* this user have a limit */
process_limit(LIMITS_DEF_USER, ltype, item, value, ctrl);
else if (domain[0]=='@') {
if (is_on_group(uname, domain+1))
process_limit(LIMITS_DEF_GROUP, ltype, item, value, ctrl);
} else if (strcmp(domain, "*") == 0)
process_limit(LIMITS_DEF_DEFAULT, ltype, item, value, ctrl);
} else
_pam_log(LOG_DEBUG,"invalid line '%s'", buf);
}
fclose(fil);
return PAM_SUCCESS;
}
static int setup_limits(const char * uname, int ctrl)
{
int i;
int retval = PAM_SUCCESS;
for (i=0; i<RLIM_NLIMITS; i++) {
if (limits[i].limit.rlim_cur > limits[i].limit.rlim_max)
limits[i].limit.rlim_cur = limits[i].limit.rlim_max;
retval |= setrlimit(i, &limits[i].limit);
}
if (retval != PAM_SUCCESS)
retval = LIMIT_ERR;
if (login_limit > 0) {
if (check_logins(uname, login_limit, ctrl) == LOGIN_ERR)
retval |= LOGIN_ERR;
} else if (login_limit == 0)
retval |= LOGIN_ERR;
return retval;
}
/* now the session stuff */
PAM_EXTERN int pam_sm_open_session(pam_handle_t *pamh, int flags,
int argc, const char **argv)
{
int retval;
char *user_name;
struct passwd *pwd;
int ctrl;
D(("called."));
memset(conf_file, 0, sizeof(conf_file));
ctrl = _pam_parse(argc, argv);
retval = pam_get_item( pamh, PAM_USER, (void*) &user_name );
if ( user_name == NULL || retval != PAM_SUCCESS ) {
_pam_log(LOG_CRIT, "open_session - error recovering username");
return PAM_SESSION_ERR;
}
setpwent();
pwd = getpwnam(user_name);
endpwent();
if (!pwd) {
if (ctrl & PAM_DEBUG_ARG)
_pam_log(LOG_WARNING, "open_session username '%s' does not exist",
user_name);
return PAM_SESSION_ERR;
}
/* do not impose limits on UID 0 accounts */
if (!pwd->pw_uid) {
if (ctrl & PAM_DEBUG_ARG)
_pam_log(LOG_DEBUG, "user '%s' have UID 0 - no limits imposed",
user_name);
return PAM_SUCCESS;
}
retval = init_limits();
if (retval != PAM_SUCCESS) {
_pam_log(LOG_WARNING, "can not initialize");
return PAM_IGNORE;
}
retval = parse_config_file(pwd->pw_name,ctrl);
if (retval != PAM_SUCCESS) {
_pam_log(LOG_WARNING, "error parsing the configuration file");
return PAM_IGNORE;
}
retval = setup_limits(pwd->pw_name, ctrl);
if (retval & LOGIN_ERR) {
printf("\nToo many logins for '%s'\n",pwd->pw_name);
sleep(2);
return PAM_PERM_DENIED;
}
return PAM_SUCCESS;
}
PAM_EXTERN int pam_sm_close_session(pam_handle_t *pamh, int flags,
int argc, const char **argv)
{
/* nothing to do */
return PAM_SUCCESS;
}
#ifdef PAM_STATIC
/* static module data */
struct pam_module _pam_limits_modstruct = {
"pam_limits",
NULL,
NULL,
NULL,
pam_sm_open_session,
pam_sm_close_session,
NULL
};
#endif
/*
* Copyright (c) Cristian Gafton, 1996-1997, <gafton@redhat.com>
* All rights reserved.
*
* 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, 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.
*/