login_class.c revision 22084
121288Sdavidn/*- 221288Sdavidn * Copyright (c) 1996 by 321288Sdavidn * Sean Eric Fagan <sef@kithrup.com> 421288Sdavidn * David Nugent <davidn@blaze.net.au> 521288Sdavidn * All rights reserved. 621288Sdavidn * 721288Sdavidn * Redistribution and use in source and binary forms, with or without 821288Sdavidn * modification, is permitted provided that the following conditions 921288Sdavidn * are met: 1021288Sdavidn * 1. Redistributions of source code must retain the above copyright 1121288Sdavidn * notice immediately at the beginning of the file, without modification, 1221288Sdavidn * this list of conditions, and the following disclaimer. 1321288Sdavidn * 2. Redistributions in binary form must reproduce the above copyright 1421288Sdavidn * notice, this list of conditions and the following disclaimer in the 1521288Sdavidn * documentation and/or other materials provided with the distribution. 1621288Sdavidn * 3. This work was done expressly for inclusion into FreeBSD. Other use 1721288Sdavidn * is permitted provided this notation is included. 1821288Sdavidn * 4. Absolutely no warranty of function or purpose is made by the authors. 1921288Sdavidn * 5. Modifications may be freely made to this file providing the above 2021288Sdavidn * conditions are met. 2121288Sdavidn * 2221288Sdavidn * High-level routines relating to use of the user capabilities database 2321288Sdavidn * 2421673Sjkh * $FreeBSD: head/lib/libutil/login_class.c 22084 1997-01-29 06:02:49Z davidn $ 2521288Sdavidn */ 2621288Sdavidn 2721288Sdavidn#include <stdio.h> 2821288Sdavidn#include <stdlib.h> 2921288Sdavidn#include <string.h> 3021288Sdavidn#include <unistd.h> 3121288Sdavidn#include <errno.h> 3221288Sdavidn#include <sys/types.h> 3322084Sdavidn#include <sys/stat.h> 3421288Sdavidn#include <sys/time.h> 3521288Sdavidn#include <sys/resource.h> 3621288Sdavidn#include <fcntl.h> 3721288Sdavidn#include <pwd.h> 3821288Sdavidn#include <syslog.h> 3921288Sdavidn#include <login_cap.h> 4021288Sdavidn#include <paths.h> 4121288Sdavidn 4221288Sdavidn 4321288Sdavidn#undef UNKNOWN 4421288Sdavidn#define UNKNOWN "su" 4521288Sdavidn 4621288Sdavidn 4721288Sdavidnstatic struct login_res { 4821288Sdavidn const char * what; 4921288Sdavidn rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); 5021288Sdavidn int why; 5121288Sdavidn} resources[] = { 5221288Sdavidn { "cputime", login_getcaptime, RLIMIT_CPU }, 5321288Sdavidn { "filesize", login_getcapsize, RLIMIT_FSIZE }, 5421288Sdavidn { "datasize", login_getcapsize, RLIMIT_DATA }, 5521288Sdavidn { "stacksize", login_getcapsize, RLIMIT_STACK }, 5621288Sdavidn { "coredumpsize", login_getcapsize, RLIMIT_CORE }, 5721288Sdavidn { "memoryuse", login_getcapsize, RLIMIT_RSS }, 5821288Sdavidn { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, 5921288Sdavidn { "maxproc", login_getcapnum, RLIMIT_NPROC }, 6021288Sdavidn { "openfiles", login_getcapnum, RLIMIT_NOFILE }, 6121288Sdavidn { NULL, 0, 0 } 6221288Sdavidn}; 6321288Sdavidn 6421288Sdavidn 6521288Sdavidn 6621288Sdavidnvoid 6721288Sdavidnsetclassresources(login_cap_t *lc) 6821288Sdavidn{ 6921288Sdavidn struct login_res *lr = resources; 7021288Sdavidn 7121402Sdavidn if (lc == NULL) 7221402Sdavidn return; 7321402Sdavidn 7421288Sdavidn while (lr->what != NULL) { 7521288Sdavidn struct rlimit rlim, 7621288Sdavidn newlim; 7721288Sdavidn char cur[40], 7821288Sdavidn max[40]; 7921288Sdavidn rlim_t rcur, 8021288Sdavidn rmax; 8121288Sdavidn 8221288Sdavidn sprintf(cur, "%s-cur", lr->what); 8321288Sdavidn sprintf(max, "%s-max", lr->what); 8421288Sdavidn 8521288Sdavidn /* 8621288Sdavidn * The login.conf file can have <limit>, <limit>-max, and 8721288Sdavidn * <limit>-cur entries. 8821288Sdavidn * What we do is get the current current- and maximum- limits. 8921288Sdavidn * Then, we try to get an entry for <limit> from the capability, 9021288Sdavidn * using the current and max limits we just got as the 9121288Sdavidn * default/error values. 9221288Sdavidn * *Then*, we try looking for <limit>-cur and <limit>-max, 9321288Sdavidn * again using the appropriate values as the default/error 9421288Sdavidn * conditions. 9521288Sdavidn */ 9621288Sdavidn 9721288Sdavidn getrlimit(lr->why, &rlim); 9821288Sdavidn rcur = rlim.rlim_cur; 9921288Sdavidn rmax = rlim.rlim_max; 10021288Sdavidn 10121288Sdavidn rcur = (*lr->who)(lc, lr->what, rcur, rcur); 10221288Sdavidn rmax = (*lr->who)(lc, lr->what, rmax, rmax); 10321288Sdavidn newlim.rlim_cur = (*lr->who)(lc, cur, rcur, rcur); 10421288Sdavidn newlim.rlim_max = (*lr->who)(lc, max, rmax, rmax); 10521288Sdavidn 10621288Sdavidn if (setrlimit(lr->why, &newlim) == -1) 10721288Sdavidn syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what); 10821288Sdavidn 10921288Sdavidn ++lr; 11021288Sdavidn } 11121288Sdavidn} 11221288Sdavidn 11321288Sdavidnstatic struct login_vars { 11421288Sdavidn const char * tag; 11521288Sdavidn const char * var; 11621288Sdavidn const char * def; 11721288Sdavidn} pathvars[] = { 11821288Sdavidn { "path", "PATH", NULL }, 11921288Sdavidn { "manpath", "MANPATH", NULL }, 12021288Sdavidn { NULL, NULL, NULL } 12121288Sdavidn}, envars[] = { 12221288Sdavidn { "lang", "LANG", NULL }, 12321288Sdavidn { "charset", "MM_CHARSET", NULL }, 12421288Sdavidn { "timezone", "TZ", NULL }, 12521288Sdavidn { "term", "TERM", UNKNOWN }, 12621288Sdavidn { NULL, NULL, NULL } 12721288Sdavidn}; 12821288Sdavidn 12921288Sdavidnstatic char * 13021288Sdavidnsubstvar(char * var, const struct passwd * pwd, int hlen, int pch, int nlen) 13121288Sdavidn{ 13221288Sdavidn char * np = NULL; 13321288Sdavidn 13421288Sdavidn if (var != NULL) { 13521288Sdavidn int tildes = 0; 13621288Sdavidn int dollas = 0; 13721288Sdavidn char * p; 13821288Sdavidn 13921288Sdavidn if (pwd != NULL) { 14021288Sdavidn /* 14121288Sdavidn * Count the number of ~'s in var to substitute 14221288Sdavidn */ 14321288Sdavidn p = var; 14421288Sdavidn while ((p = strchr(p, '~')) != NULL) { 14521288Sdavidn ++tildes; 14621288Sdavidn ++p; 14721288Sdavidn } 14821288Sdavidn 14921288Sdavidn /* 15021288Sdavidn * Count the number of $'s in var to substitute 15121288Sdavidn */ 15221288Sdavidn p = var; 15321288Sdavidn while ((p = strchr(p, '$')) != NULL) { 15421288Sdavidn ++dollas; 15521288Sdavidn ++p; 15621288Sdavidn } 15721288Sdavidn } 15821288Sdavidn 15921288Sdavidn np = malloc(strlen(var) + (dollas * nlen) - dollas + (tildes * (pch+hlen)) - tildes + 1); 16021288Sdavidn 16121288Sdavidn if (np != NULL) { 16221288Sdavidn p = strcpy(np, var); 16321288Sdavidn 16421288Sdavidn if (pwd != NULL) { 16521288Sdavidn /* 16621288Sdavidn * This loop does user username and homedir substitutions 16721288Sdavidn * for unescaped $ (username) and ~ (homedir) 16821288Sdavidn */ 16921288Sdavidn while (*(p += strcspn(p, "~$")) != '\0') { 17021288Sdavidn int l = strlen(p); 17121288Sdavidn 17221288Sdavidn if (p > var && *(p-1) == '\\') /* Escaped: */ 17321402Sdavidn memmove(p - 1, p, l + 1); /* Slide-out the backslash */ 17421288Sdavidn else if (*p == '~') { 17521402Sdavidn int v = pch && *(p+1) != '/'; /* Avoid double // */ 17621402Sdavidn memmove(p + hlen + v, p + 1, l); /* Subst homedir */ 17721288Sdavidn memmove(p, pwd->pw_dir, hlen); 17821402Sdavidn if (v) 17921288Sdavidn p[hlen] = '/'; 18021402Sdavidn p += hlen + v; 18121288Sdavidn } 18221288Sdavidn else /* if (*p == '$') */ { 18321402Sdavidn memmove(p + nlen, p + 1, l); /* Subst username */ 18421288Sdavidn memmove(p, pwd->pw_name, nlen); 18521288Sdavidn p += nlen; 18621288Sdavidn } 18721288Sdavidn } 18821288Sdavidn } 18921288Sdavidn } 19021288Sdavidn } 19121288Sdavidn return np; 19221288Sdavidn} 19321288Sdavidn 19421288Sdavidn 19521288Sdavidnvoid 19621288Sdavidnsetclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) 19721288Sdavidn{ 19821288Sdavidn struct login_vars * vars = paths ? pathvars : envars; 19921288Sdavidn int hlen = pwd ? strlen(pwd->pw_dir) : 0; 20021288Sdavidn int nlen = pwd ? strlen(pwd->pw_name) : 0; 20121288Sdavidn char pch = 0; 20221288Sdavidn 20321288Sdavidn if (hlen && pwd->pw_dir[hlen-1] != '/') 20421288Sdavidn ++pch; 20521288Sdavidn 20621288Sdavidn while (vars->tag != NULL) { 20721288Sdavidn char * var = paths ? login_getpath(lc, vars->tag, NULL) 20821402Sdavidn : login_getcapstr(lc, vars->tag, NULL, NULL); 20921288Sdavidn 21021288Sdavidn char * np = substvar(var, pwd, hlen, pch, nlen); 21121288Sdavidn 21221288Sdavidn if (np != NULL) { 21321288Sdavidn setenv(vars->var, np, 1); 21421288Sdavidn free(np); 21521288Sdavidn } else if (vars->def != NULL) { 21621288Sdavidn setenv(vars->var, vars->def, 0); 21721288Sdavidn } 21821288Sdavidn ++vars; 21921288Sdavidn } 22021288Sdavidn 22121288Sdavidn /* 22221288Sdavidn * If we're not processing paths, then see if there is a setenv list by 22321288Sdavidn * which the admin and/or user may set an arbitrary set of env vars. 22421288Sdavidn */ 22521288Sdavidn if (!paths) { 22621288Sdavidn char ** set_env = login_getcaplist(lc, "setenv", ","); 22721402Sdavidn 22821288Sdavidn if (set_env != NULL) { 22921288Sdavidn while (*set_env != NULL) { 23021288Sdavidn char *p = strchr(*set_env, '='); 23121402Sdavidn if (p != NULL) { /* Discard invalid entries */ 23221402Sdavidn char * np; 23321402Sdavidn 23421402Sdavidn *p++ = '\0'; 23521402Sdavidn if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 23621402Sdavidn setenv(*set_env, np, 1); 23721288Sdavidn free(np); 23821288Sdavidn } 23921288Sdavidn } 24021288Sdavidn ++set_env; 24121288Sdavidn } 24221288Sdavidn } 24321288Sdavidn } 24421288Sdavidn} 24521288Sdavidn 24621288Sdavidn 24721288Sdavidn/* 24821288Sdavidn * setclasscontext() 24921288Sdavidn * 25021288Sdavidn * For the login class <class>, set various class context values 25121288Sdavidn * (limits, mainly) to the values for that class. Which values are 25221288Sdavidn * set are controlled by <flags> -- see <login_class.h> for the 25321288Sdavidn * possible values. 25421288Sdavidn * 25521288Sdavidn * setclasscontext() can only set resources, priority, and umask. 25621288Sdavidn */ 25721288Sdavidn 25821288Sdavidnint 25921288Sdavidnsetclasscontext(const char *classname, unsigned int flags) 26021288Sdavidn{ 26121288Sdavidn int rc; 26221288Sdavidn login_cap_t * lc = login_getclassbyname(classname, NULL); 26321288Sdavidn flags &= (LOGIN_SETRESOURCES| LOGIN_SETPRIORITY|LOGIN_SETUMASK); 26421288Sdavidn rc = setusercontext(lc, NULL, 0, flags); 26521288Sdavidn login_close(lc); 26621288Sdavidn return rc; 26721288Sdavidn} 26821288Sdavidn 26921288Sdavidn 27021288Sdavidn/* 27121288Sdavidn * setusercontext() 27221288Sdavidn * 27321288Sdavidn * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 27421288Sdavidn * set the context as in setclasscontext(). <flags> controls which 27521288Sdavidn * values are set. 27621288Sdavidn * 27721288Sdavidn * The difference between setclasscontext() and setusercontext() is 27821288Sdavidn * that the former sets things up for an already-existing process, 27921288Sdavidn * while the latter sets things up from a root context. Such as might 28021288Sdavidn * be called from login(1). 28121288Sdavidn * 28221288Sdavidn */ 28321288Sdavidn 28421288Sdavidnint 28521288Sdavidnsetusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 28621288Sdavidn{ 28721288Sdavidn int i; 28821288Sdavidn login_cap_t * llc = NULL; 28921288Sdavidn 29021288Sdavidn if (lc == NULL) 29121288Sdavidn { 29221402Sdavidn if (pwd != NULL && (lc = login_getclass(pwd)) != NULL) 29321402Sdavidn llc = lc; /* free this when we're done */ 29421288Sdavidn } 29521288Sdavidn 29621288Sdavidn if (flags & LOGIN_SETPATH) 29721288Sdavidn pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 29821288Sdavidn 29921288Sdavidn /* 30021288Sdavidn * Set the process priority 30121288Sdavidn */ 30221288Sdavidn if (flags & LOGIN_SETPRIORITY) { 30321288Sdavidn int pri = (int)login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 30421288Sdavidn pri = (pri < PRIO_MIN) ? PRIO_MIN : (pri > PRIO_MAX) ? PRIO_MAX : pri; 30521288Sdavidn if (setpriority(PRIO_PROCESS, 0, pri) != 0) 30621288Sdavidn syslog(LOG_WARNING, "setpriority '%s': %m", pwd->pw_name); 30721288Sdavidn } 30821288Sdavidn 30921288Sdavidn /* 31021288Sdavidn * Set resources 31121288Sdavidn */ 31221288Sdavidn if (flags & LOGIN_SETRESOURCES) 31321288Sdavidn setclassresources(lc); 31421288Sdavidn 31521288Sdavidn /* 31621288Sdavidn * Set the sessions login 31721288Sdavidn */ 31821288Sdavidn if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 31921288Sdavidn syslog(LOG_ERR, "setlogin '%s': %m", pwd->pw_name); 32021288Sdavidn login_close(llc); 32121402Sdavidn return -1; 32221288Sdavidn } 32321288Sdavidn 32421288Sdavidn /* 32521288Sdavidn * Setup the user's group permissions 32621288Sdavidn */ 32721288Sdavidn if (flags & LOGIN_SETGROUP) { 32821288Sdavidn if (setgid(pwd->pw_gid) != 0) 32921288Sdavidn syslog(LOG_WARNING, "setgid %ld: %m", (long)pwd->pw_gid); 33021288Sdavidn if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) 33121288Sdavidn syslog(LOG_WARNING, "initgroups '%s': %m", pwd->pw_name); 33221288Sdavidn } 33321288Sdavidn 33421288Sdavidn /* 33521288Sdavidn * FreeBSD extension: here we (might) loop and do this twice. 33621288Sdavidn * First, for the class we have been given, and next for 33721288Sdavidn * any user overrides in ~/.login.conf the user's home directory. 33821288Sdavidn */ 33921288Sdavidn if (flags & LOGIN_SETUMASK) 34021288Sdavidn umask(LOGIN_DEFUMASK); /* Set default umask up front */ 34121288Sdavidn 34221288Sdavidn i = 0; 34321288Sdavidn while (i < 2 && lc != NULL) { 34421288Sdavidn 34521288Sdavidn if (flags & LOGIN_SETUMASK) { 34621288Sdavidn rlim_t tmp = login_getcapnum(lc, "umask", RLIM_INFINITY, RLIM_INFINITY); 34721288Sdavidn if (tmp != RLIM_INFINITY) 34821288Sdavidn umask((mode_t)tmp); 34921288Sdavidn } 35021288Sdavidn 35121288Sdavidn if (flags & LOGIN_SETPATH) 35221288Sdavidn setclassenvironment(lc, pwd, 1); 35321288Sdavidn 35421288Sdavidn if (flags & LOGIN_SETENV) 35521288Sdavidn setclassenvironment(lc, pwd, 0); 35621288Sdavidn 35721288Sdavidn if (i++ == 0) /* Play it again, Sam */ 35821288Sdavidn lc = (pwd == NULL) ? NULL : login_getuserclass(pwd); 35921288Sdavidn } 36021288Sdavidn 36121288Sdavidn login_close(lc); /* User's private 'me' class */ 36221288Sdavidn login_close(llc); /* Class we opened */ 36321288Sdavidn 36421402Sdavidn /* 36521402Sdavidn * This needs to be done after all of the above. 36621402Sdavidn * Do it last so we avoid getting killed and dropping core 36721402Sdavidn */ 36821402Sdavidn if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 36921402Sdavidn syslog(LOG_ERR, "setuid %ld: %m", uid); 37021402Sdavidn login_close(llc); 37121402Sdavidn return -1; /* Paranoia again */ 37221402Sdavidn } 37321402Sdavidn 37421288Sdavidn return 0; 37521288Sdavidn} 37621288Sdavidn 377