freebsd-dev/lib/libutil/login_class.c
David Nugent 68bbf3adb0 Library functions relating to the login class capabilities database,
including manpages.
See also login_cap.h.
1997-01-04 16:50:08 +00:00

372 lines
9.6 KiB
C

/*-
* Copyright (c) 1996 by
* Sean Eric Fagan <sef@kithrup.com>
* David Nugent <davidn@blaze.net.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice immediately at the beginning of the file, without modification,
* this list of conditions, and the following disclaimer.
* 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. This work was done expressly for inclusion into FreeBSD. Other use
* is permitted provided this notation is included.
* 4. Absolutely no warranty of function or purpose is made by the authors.
* 5. Modifications may be freely made to this file providing the above
* conditions are met.
*
* High-level routines relating to use of the user capabilities database
*
* $Id$
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <fcntl.h>
#include <pwd.h>
#include <syslog.h>
#include <login_cap.h>
#include <paths.h>
#undef UNKNOWN
#define UNKNOWN "su"
static struct login_res {
const char * what;
rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t);
int why;
} resources[] = {
{ "cputime", login_getcaptime, RLIMIT_CPU },
{ "filesize", login_getcapsize, RLIMIT_FSIZE },
{ "datasize", login_getcapsize, RLIMIT_DATA },
{ "stacksize", login_getcapsize, RLIMIT_STACK },
{ "coredumpsize", login_getcapsize, RLIMIT_CORE },
{ "memoryuse", login_getcapsize, RLIMIT_RSS },
{ "memorylocked", login_getcapsize, RLIMIT_MEMLOCK },
{ "maxproc", login_getcapnum, RLIMIT_NPROC },
{ "openfiles", login_getcapnum, RLIMIT_NOFILE },
{ NULL, 0, 0 }
};
void
setclassresources(login_cap_t *lc)
{
struct login_res *lr = resources;
while (lr->what != NULL) {
struct rlimit rlim,
newlim;
char cur[40],
max[40];
rlim_t rcur,
rmax;
sprintf(cur, "%s-cur", lr->what);
sprintf(max, "%s-max", lr->what);
/*
* The login.conf file can have <limit>, <limit>-max, and
* <limit>-cur entries.
* What we do is get the current current- and maximum- limits.
* Then, we try to get an entry for <limit> from the capability,
* using the current and max limits we just got as the
* default/error values.
* *Then*, we try looking for <limit>-cur and <limit>-max,
* again using the appropriate values as the default/error
* conditions.
*/
getrlimit(lr->why, &rlim);
rcur = rlim.rlim_cur;
rmax = rlim.rlim_max;
rcur = (*lr->who)(lc, lr->what, rcur, rcur);
rmax = (*lr->who)(lc, lr->what, rmax, rmax);
newlim.rlim_cur = (*lr->who)(lc, cur, rcur, rcur);
newlim.rlim_max = (*lr->who)(lc, max, rmax, rmax);
if (setrlimit(lr->why, &newlim) == -1)
syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what);
++lr;
}
}
static struct login_vars {
const char * tag;
const char * var;
const char * def;
} pathvars[] = {
{ "path", "PATH", NULL },
{ "manpath", "MANPATH", NULL },
{ NULL, NULL, NULL }
}, envars[] = {
{ "lang", "LANG", NULL },
{ "charset", "MM_CHARSET", NULL },
{ "timezone", "TZ", NULL },
{ "term", "TERM", UNKNOWN },
{ NULL, NULL, NULL }
};
static char *
substvar(char * var, const struct passwd * pwd, int hlen, int pch, int nlen)
{
char * np = NULL;
if (var != NULL) {
int tildes = 0;
int dollas = 0;
char * p;
if (pwd != NULL) {
/*
* Count the number of ~'s in var to substitute
*/
p = var;
while ((p = strchr(p, '~')) != NULL) {
++tildes;
++p;
}
/*
* Count the number of $'s in var to substitute
*/
p = var;
while ((p = strchr(p, '$')) != NULL) {
++dollas;
++p;
}
}
np = malloc(strlen(var) + (dollas * nlen) - dollas + (tildes * (pch+hlen)) - tildes + 1);
if (np != NULL) {
p = strcpy(np, var);
if (pwd != NULL) {
/*
* This loop does user username and homedir substitutions
* for unescaped $ (username) and ~ (homedir)
*/
while (*(p += strcspn(p, "~$")) != '\0') {
int l = strlen(p);
if (p > var && *(p-1) == '\\') /* Escaped: */
memmove(p - 1, p, l + 1); /* Slide-out the backslash */
else if (*p == '~') {
memmove(p + 1, p + hlen + pch, l); /* Subst homedir */
memmove(p, pwd->pw_dir, hlen);
if (pch)
p[hlen] = '/';
p += hlen + pch;
}
else /* if (*p == '$') */ {
memmove(p + 1, p + nlen, l); /* Subst username */
memmove(p, pwd->pw_name, nlen);
p += nlen;
}
}
}
}
}
return np;
}
void
setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths)
{
struct login_vars * vars = paths ? pathvars : envars;
int hlen = pwd ? strlen(pwd->pw_dir) : 0;
int nlen = pwd ? strlen(pwd->pw_name) : 0;
char pch = 0;
if (hlen && pwd->pw_dir[hlen-1] != '/')
++pch;
while (vars->tag != NULL) {
char * var = paths ? login_getpath(lc, vars->tag, NULL)
: login_getcapstr(lc, vars->tag, NULL, NULL);
char * np = substvar(var, pwd, hlen, pch, nlen);
if (np != NULL) {
setenv(vars->var, np, 1);
free(np);
} else if (vars->def != NULL) {
setenv(vars->var, vars->def, 0);
}
++vars;
}
/*
* If we're not processing paths, then see if there is a setenv list by
* which the admin and/or user may set an arbitrary set of env vars.
*/
if (!paths) {
char ** set_env = login_getcaplist(lc, "setenv", ",");
if (set_env != NULL) {
while (*set_env != NULL) {
char *p = strchr(*set_env, '=');
if (p != NULL) {
char * np = substvar(set_env[1], pwd, hlen, pch, nlen);
if (np != NULL) {
setenv(set_env[0], np, 1);
free(np);
}
}
++set_env;
}
}
}
}
/*
* setclasscontext()
*
* For the login class <class>, set various class context values
* (limits, mainly) to the values for that class. Which values are
* set are controlled by <flags> -- see <login_class.h> for the
* possible values.
*
* setclasscontext() can only set resources, priority, and umask.
*/
int
setclasscontext(const char *classname, unsigned int flags)
{
int rc;
login_cap_t * lc = login_getclassbyname(classname, NULL);
flags &= (LOGIN_SETRESOURCES| LOGIN_SETPRIORITY|LOGIN_SETUMASK);
rc = setusercontext(lc, NULL, 0, flags);
login_close(lc);
return rc;
}
/*
* setusercontext()
*
* Given a login class <lc> and a user in <pwd>, with a uid <uid>,
* set the context as in setclasscontext(). <flags> controls which
* values are set.
*
* The difference between setclasscontext() and setusercontext() is
* that the former sets things up for an already-existing process,
* while the latter sets things up from a root context. Such as might
* be called from login(1).
*
*/
int
setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags)
{
int i;
login_cap_t * llc = NULL;
if (lc == NULL)
{
if (pwd == NULL || (lc = login_getclass(pwd)) == NULL) {
return -1;
}
llc = lc; /* free this when we're done */
}
if (flags & LOGIN_SETPATH)
pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH;
/*
* Set the process priority
*/
if (flags & LOGIN_SETPRIORITY) {
int pri = (int)login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
pri = (pri < PRIO_MIN) ? PRIO_MIN : (pri > PRIO_MAX) ? PRIO_MAX : pri;
if (setpriority(PRIO_PROCESS, 0, pri) != 0)
syslog(LOG_WARNING, "setpriority '%s': %m", pwd->pw_name);
}
/*
* Set resources
*/
if (flags & LOGIN_SETRESOURCES)
setclassresources(lc);
/*
* Set the sessions login
*/
if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) {
syslog(LOG_ERR, "setlogin '%s': %m", pwd->pw_name);
login_close(llc);
return -1; /* You can't be too paranoid */
}
/*
* Setup the user's group permissions
*/
if (flags & LOGIN_SETGROUP) {
/* XXX is it really a good idea to let errors here go? */
if (setgid(pwd->pw_gid) != 0)
syslog(LOG_WARNING, "setgid %ld: %m", (long)pwd->pw_gid);
if (initgroups(pwd->pw_name, pwd->pw_gid) == -1)
syslog(LOG_WARNING, "initgroups '%s': %m", pwd->pw_name);
}
/*
* This needs to be done after all of the above.
*/
if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) {
syslog(LOG_ERR, "setuid %ld: %m", uid);
login_close(llc);
return -1; /* Paranoia again */
}
/*
* FreeBSD extension: here we (might) loop and do this twice.
* First, for the class we have been given, and next for
* any user overrides in ~/.login.conf the user's home directory.
*/
if (flags & LOGIN_SETUMASK)
umask(LOGIN_DEFUMASK); /* Set default umask up front */
i = 0;
while (i < 2 && lc != NULL) {
if (flags & LOGIN_SETUMASK) {
rlim_t tmp = login_getcapnum(lc, "umask", RLIM_INFINITY, RLIM_INFINITY);
if (tmp != RLIM_INFINITY)
umask((mode_t)tmp);
}
if (flags & LOGIN_SETPATH)
setclassenvironment(lc, pwd, 1);
if (flags & LOGIN_SETENV)
setclassenvironment(lc, pwd, 0);
if (i++ == 0) /* Play it again, Sam */
lc = (pwd == NULL) ? NULL : login_getuserclass(pwd);
}
login_close(lc); /* User's private 'me' class */
login_close(llc); /* Class we opened */
return 0;
}