/* * pam_limits - impose resource limits when opening a user session * * 1.6 - modified for PLD (added process priority settings) * by Marcin Korzonek * 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 "config.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef UT_USER /* some systems have ut_name instead of ut_user */ #define UT_USER ut_user #endif #include #include /* 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_ALLGROUP 2 /* limit was set by a group entry */ #define LIMITS_DEF_ALL 3 /* limit was set by an default entry */ #define LIMITS_DEF_DEFAULT 4 /* limit was set by an default entry */ #define LIMITS_DEF_NONE 5 /* this limit was not set yet */ static const char *limits_def_names[] = { "USER", "GROUP", "ALLGROUP", "ALL", "DEFAULT", "NONE", NULL }; struct user_limits_struct { int supported; int src_soft; int src_hard; struct rlimit limit; }; /* internal data */ struct pam_limit_s { int login_limit; /* the max logins limit */ int login_limit_def; /* which entry set the login limit */ int flag_numsyslogins; /* whether to limit logins only for a specific user or to count all logins */ int priority; /* the priority to run user process with */ struct user_limits_struct limits[RLIM_NLIMITS]; char conf_file[BUFSIZ]; int utmp_after_pam_call; char login_group[LINE_LENGTH]; }; #define LIMIT_LOGIN RLIM_NLIMITS+1 #define LIMIT_NUMSYSLOGINS RLIM_NLIMITS+2 #define LIMIT_PRI RLIM_NLIMITS+3 #define LIMIT_SOFT 1 #define LIMIT_HARD 2 #define PAM_SM_SESSION #include #include #include #include /* argument parsing */ #define PAM_DEBUG_ARG 0x0001 #define PAM_DO_SETREUID 0x0002 #define PAM_UTMP_EARLY 0x0004 static int _pam_parse (const pam_handle_t *pamh, int argc, const char **argv, struct pam_limit_s *pl) { 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)) { strncpy(pl->conf_file,*argv+5,sizeof(pl->conf_file)-1); } else if (!strncmp(*argv,"change_uid",10)) { ctrl |= PAM_DO_SETREUID; } else if (!strcmp(*argv,"utmp_early")) { ctrl |= PAM_UTMP_EARLY; } else { pam_syslog(pamh,LOG_ERR,"pam_parse: unknown option; %s",*argv); } } pl->conf_file[sizeof(pl->conf_file) - 1] = '\0'; return ctrl; } #define LIMITED_OK 0 /* limit setting appeared to work */ #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 (pam_handle_t *pamh, const char *name, int limit, int ctrl, struct pam_limit_s *pl) { struct utmp *ut; int count; if (ctrl & PAM_DEBUG_ARG) { pam_syslog(pamh,LOG_DEBUG, "checking logins for '%s' (maximum of %d)\n", name, limit); } if (limit < 0) return 0; /* no limits imposed */ if (limit == 0) /* maximum 0 logins ? */ { pam_syslog(pamh,LOG_WARNING, "No logins allowed for '%s'\n", name); return LOGIN_ERR; } setutent(); /* Because there is no definition about when an application actually adds a utmp entry, some applications bizarrely do the utmp call before the have PAM authenticate them to the system: you're logged it, sort of...? Anyway, you can use the "utmp_early" module argument in your PAM config file to make allowances for this sort of problem. (There should be a PAM standard for this, since if a module wants to actually map a username then any early utmp entry will be for the unmapped name = broken.) */ if (ctrl & PAM_UTMP_EARLY) { count = 0; } else { count = 1; } while((ut = getutent())) { #ifdef USER_PROCESS if (ut->ut_type != USER_PROCESS) { continue; } #endif if (ut->UT_USER[0] == '\0') { continue; } if (!pl->flag_numsyslogins) { if (((pl->login_limit_def == LIMITS_DEF_USER) || (pl->login_limit_def == LIMITS_DEF_GROUP) || (pl->login_limit_def == LIMITS_DEF_DEFAULT)) && strncmp(name, ut->UT_USER, sizeof(ut->UT_USER)) != 0) { continue; } if ((pl->login_limit_def == LIMITS_DEF_ALLGROUP) && !_pammodutil_user_in_group_nam_nam(pamh, ut->UT_USER, pl->login_group)) { continue; } } if (++count > limit) { break; } } endutent(); if (count > limit) { if (name) { pam_syslog(pamh,LOG_WARNING, "Too many logins (max %d) for %s", limit, name); } else { pam_syslog(pamh,LOG_WARNING, "Too many system logins (max %d)", limit); } return LOGIN_ERR; } return 0; } static int init_limits(struct pam_limit_s *pl) { int i; int retval = PAM_SUCCESS; D(("called.")); for(i = 0; i < RLIM_NLIMITS; i++) { int r = getrlimit(i, &pl->limits[i].limit); if (r == -1) { pl->limits[i].supported = 0; if (errno != EINVAL) { retval = !PAM_SUCCESS; } } else { pl->limits[i].supported = 1; pl->limits[i].src_soft = LIMITS_DEF_NONE; pl->limits[i].src_hard = LIMITS_DEF_NONE; } } errno = 0; pl->priority = getpriority (PRIO_PROCESS, 0); if (pl->priority == -1 && errno != 0) retval = !PAM_SUCCESS; pl->login_limit = -2; pl->login_limit_def = LIMITS_DEF_NONE; return retval; } static void process_limit (const pam_handle_t *pamh, int source, const char *lim_type, const char *lim_item, const char *lim_value, int ctrl, struct pam_limit_s *pl) { int limit_item; int limit_type = 0; int int_value = 0; rlim_t rlimit_value = 0; char *endptr; const char *value_orig = lim_value; if (ctrl & PAM_DEBUG_ARG) pam_syslog(pamh,LOG_DEBUG, "%s: processing %s %s %s for %s\n", __FUNCTION__,lim_type,lim_item,lim_value, limits_def_names[source]); 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; #ifdef RLIMIT_LOCKS else if (strcmp(lim_item, "locks") == 0) limit_item = RLIMIT_LOCKS; #endif #ifdef RLIMIT_SIGPENDING else if (strcmp(lim_item, "sigpending") == 0) limit_item = RLIMIT_SIGPENDING; #endif #ifdef RLIMIT_MSGQUEUE else if (strcmp(lim_item, "msgqueue") == 0) limit_item = RLIMIT_MSGQUEUE; #endif #ifdef RLIMIT_NICE else if (strcmp(lim_item, "nice") == 0) limit_item = RLIMIT_NICE; #endif #ifdef RLIMIT_RTPRIO else if (strcmp(lim_item, "rtprio") == 0) limit_item = RLIMIT_RTPRIO; #endif else if (strcmp(lim_item, "maxlogins") == 0) { limit_item = LIMIT_LOGIN; pl->flag_numsyslogins = 0; } else if (strcmp(lim_item, "maxsyslogins") == 0) { limit_item = LIMIT_NUMSYSLOGINS; pl->flag_numsyslogins = 1; } else if (strcmp(lim_item, "priority") == 0) { limit_item = LIMIT_PRI; } else { pam_syslog(pamh,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_syslog(pamh,LOG_DEBUG,"unknown limit type '%s'", lim_type); return; } if (limit_item != LIMIT_PRI #ifdef RLIMIT_NICE && limit_item != RLIMIT_NICE #endif && (strcmp(lim_value, "-1") == 0 || strcmp(lim_value, "-") == 0 || strcmp(lim_value, "unlimited") == 0 || strcmp(lim_value, "infinity") == 0)) { int_value = -1; rlimit_value = RLIM_INFINITY; } else if (limit_item == LIMIT_PRI || limit_item == LIMIT_LOGIN || #ifdef RLIMIT_NICE limit_item == RLIMIT_NICE || #endif limit_item == LIMIT_NUMSYSLOGINS) { long temp; temp = strtol (lim_value, &endptr, 10); temp = temp < INT_MAX ? temp : INT_MAX; int_value = temp > INT_MIN ? temp : INT_MIN; if (int_value == 0 && value_orig == endptr) { pam_syslog(pamh,LOG_DEBUG, "wrong limit value '%s' for limit type '%s'", lim_value, lim_type); return; } } else { #ifdef __USE_FILE_OFFSET64 rlimit_value = strtoull (lim_value, &endptr, 10); #else rlimit_value = strtoul (lim_value, &endptr, 10); #endif if (rlimit_value == 0 && value_orig == endptr) { pam_syslog(pamh,LOG_DEBUG, "wrong limit value '%s' for limit type '%s'", lim_value, lim_type); return; } } /* one more special case when limiting logins */ if ((source == LIMITS_DEF_ALL || source == LIMITS_DEF_ALLGROUP) && (limit_item != LIMIT_LOGIN)) { if (ctrl & PAM_DEBUG_ARG) pam_syslog(pamh,LOG_DEBUG, "'%%' domain valid for maxlogins type only"); return; } switch(limit_item) { case RLIMIT_CPU: if (rlimit_value != RLIM_INFINITY) rlimit_value *= 60; break; case RLIMIT_FSIZE: case RLIMIT_DATA: case RLIMIT_STACK: case RLIMIT_CORE: case RLIMIT_RSS: case RLIMIT_MEMLOCK: case RLIMIT_AS: if (rlimit_value != RLIM_INFINITY) rlimit_value *= 1024; break; #ifdef RLIMIT_NICE case RLIMIT_NICE: if (int_value > 19) int_value = 19; rlimit_value = 19 - int_value; #endif break; } if ( (limit_item != LIMIT_LOGIN) && (limit_item != LIMIT_NUMSYSLOGINS) && (limit_item != LIMIT_PRI) ) { if (limit_type & LIMIT_SOFT) { if (pl->limits[limit_item].src_soft < source) { return; } else { pl->limits[limit_item].limit.rlim_cur = rlimit_value; pl->limits[limit_item].src_soft = source; } } if (limit_type & LIMIT_HARD) { if (pl->limits[limit_item].src_hard < source) { return; } else { pl->limits[limit_item].limit.rlim_max = rlimit_value; pl->limits[limit_item].src_hard = source; } } } else { /* recent kernels support negative priority limits (=raise priority) */ if (limit_item == LIMIT_PRI) { pl->priority = int_value; } else { if (pl->login_limit_def < source) { return; } else { pl->login_limit = int_value; pl->login_limit_def = source; } } } return; } static int parse_config_file(pam_handle_t *pamh, const char *uname, int ctrl, struct pam_limit_s *pl) { FILE *fil; char buf[LINE_LENGTH]; #define CONF_FILE (pl->conf_file[0])?pl->conf_file:LIMITS_FILE /* check for the LIMITS_FILE */ if (ctrl & PAM_DEBUG_ARG) pam_syslog(pamh,LOG_DEBUG,"reading settings from '%s'", CONF_FILE); fil = fopen(CONF_FILE, "r"); if (fil == NULL) { pam_syslog (pamh, 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; size_t j; char *tptr; tptr = buf; /* skip the leading white space */ while (*tptr && isspace(*tptr)) tptr++; strncpy(buf, tptr, sizeof(buf)-1); buf[sizeof(buf)-1] = '\0'; /* 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); D(("scanned line[%d]: domain[%s], ltype[%s], item[%s], value[%s]", i, domain, ltype, item, value)); 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(pamh, LIMITS_DEF_USER, ltype, item, value, ctrl, pl); else if (domain[0]=='@') { if (ctrl & PAM_DEBUG_ARG) { pam_syslog(pamh,LOG_DEBUG, "checking if %s is in group %s", uname, domain + 1); } if (_pammodutil_user_in_group_nam_nam(pamh, uname, domain+1)) process_limit(pamh, LIMITS_DEF_GROUP, ltype, item, value, ctrl, pl); } else if (domain[0]=='%') { if (ctrl & PAM_DEBUG_ARG) { pam_syslog(pamh,LOG_DEBUG, "checking if %s is in group %s", uname, domain + 1); } if (strcmp(domain,"%") == 0) process_limit(pamh, LIMITS_DEF_ALL, ltype, item, value, ctrl, pl); else if (_pammodutil_user_in_group_nam_nam(pamh, uname, domain+1)) { strcpy(pl->login_group, domain+1); process_limit(pamh, LIMITS_DEF_ALLGROUP, ltype, item, value, ctrl, pl); } } else if (strcmp(domain, "*") == 0) process_limit(pamh, LIMITS_DEF_DEFAULT, ltype, item, value, ctrl, pl); } else if (i == 2 && ltype[0] == '-') { /* Probably a no-limit line */ if (strcmp(uname, domain) == 0) { if (ctrl & PAM_DEBUG_ARG) { pam_syslog(pamh,LOG_DEBUG, "no limits for '%s'", uname); } fclose(fil); return PAM_IGNORE; } else if (domain[0] == '@' && _pammodutil_user_in_group_nam_nam(pamh, uname, domain+1)) { if (ctrl & PAM_DEBUG_ARG) { pam_syslog(pamh,LOG_DEBUG, "no limits for '%s' in group '%s'", uname, domain+1); } fclose(fil); return PAM_IGNORE; } } else { pam_syslog(pamh,LOG_DEBUG,"invalid line '%s' - skipped", buf); } } fclose(fil); return PAM_SUCCESS; } static int setup_limits(pam_handle_t *pamh, const char *uname, uid_t uid, int ctrl, struct pam_limit_s *pl) { int i; int status; int retval = LIMITED_OK; if (uid == 0) { /* do not impose limits (+ve limits anyway) on the superuser */ if (pl->priority > 0) { if (ctrl & PAM_DEBUG_ARG) { pam_syslog(pamh,LOG_DEBUG, "user '%s' has UID 0 - no limits imposed", uname); } pl->priority = 0; } } for (i=0, status=LIMITED_OK; ilimits[i].supported) { /* skip it if its not known to the system */ continue; } if (pl->limits[i].src_soft == LIMITS_DEF_NONE && pl->limits[i].src_hard == LIMITS_DEF_NONE) { /* skip it if its not initialized */ continue; } if (pl->limits[i].limit.rlim_cur > pl->limits[i].limit.rlim_max) pl->limits[i].limit.rlim_cur = pl->limits[i].limit.rlim_max; status |= setrlimit(i, &pl->limits[i].limit); } if (status) { retval = LIMIT_ERR; } status = setpriority(PRIO_PROCESS, 0, pl->priority); if (status != 0) { retval = LIMIT_ERR; } if (uid == 0) { D(("skip login limit check for uid=0")); } else if (pl->login_limit > 0) { if (check_logins(pamh, uname, pl->login_limit, ctrl, pl) == LOGIN_ERR) { retval |= LOGIN_ERR; } } else if (pl->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 UNUSED, int argc, const char **argv) { int retval; char *user_name; struct passwd *pwd; int ctrl; struct pam_limit_s pl; D(("called.")); memset(&pl, 0, sizeof(pl)); ctrl = _pam_parse(pamh, argc, argv, &pl); retval = pam_get_item( pamh, PAM_USER, (void*) &user_name ); if ( user_name == NULL || retval != PAM_SUCCESS ) { pam_syslog(pamh,LOG_CRIT, "open_session - error recovering username"); return PAM_SESSION_ERR; } pwd = getpwnam(user_name); if (!pwd) { if (ctrl & PAM_DEBUG_ARG) pam_syslog(pamh,LOG_WARNING, "open_session username '%s' does not exist", user_name); return PAM_SESSION_ERR; } retval = init_limits(&pl); if (retval != PAM_SUCCESS) { pam_syslog(pamh,LOG_WARNING, "cannot initialize"); return PAM_ABORT; } retval = parse_config_file(pamh, pwd->pw_name, ctrl, &pl); if (retval == PAM_IGNORE) { D(("the configuration file has an applicable ' -' entry")); return PAM_SUCCESS; } if (retval != PAM_SUCCESS) { pam_syslog(pamh,LOG_WARNING, "error parsing the configuration file"); return retval; } if (ctrl & PAM_DO_SETREUID) { setreuid(pwd->pw_uid, -1); } retval = setup_limits(pamh, pwd->pw_name, pwd->pw_uid, ctrl, &pl); if (retval != LIMITED_OK) { return PAM_PERM_DENIED; } return PAM_SUCCESS; } PAM_EXTERN int pam_sm_close_session (pam_handle_t *pamh UNUSED, int flags UNUSED, int argc UNUSED, const char **argv UNUSED) { /* 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, * 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. */