411 lines
11 KiB
C
411 lines
11 KiB
C
/*-
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* Copyright (c) 1996 by
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* Sean Eric Fagan <sef@kithrup.com>
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* David Nugent <davidn@blaze.net.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, is permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice immediately at the beginning of the file, without modification,
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* this list of conditions, and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. This work was done expressly for inclusion into FreeBSD. Other use
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* is permitted provided this notation is included.
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* 4. Absolutely no warranty of function or purpose is made by the authors.
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* 5. Modifications may be freely made to this file providing the above
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* conditions are met.
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*
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* High-level routines relating to use of the user capabilities database
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*
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* $FreeBSD$
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <fcntl.h>
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#include <pwd.h>
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#include <syslog.h>
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#include <login_cap.h>
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#include <paths.h>
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#include <sys/rtprio.h>
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#undef UNKNOWN
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#define UNKNOWN "su"
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static struct login_res {
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const char *what;
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rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t);
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int why;
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} resources[] = {
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{ "cputime", login_getcaptime, RLIMIT_CPU },
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{ "filesize", login_getcapsize, RLIMIT_FSIZE },
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{ "datasize", login_getcapsize, RLIMIT_DATA },
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{ "stacksize", login_getcapsize, RLIMIT_STACK },
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{ "memoryuse", login_getcapsize, RLIMIT_RSS },
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{ "memorylocked", login_getcapsize, RLIMIT_MEMLOCK },
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{ "maxproc", login_getcapnum, RLIMIT_NPROC },
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{ "openfiles", login_getcapnum, RLIMIT_NOFILE },
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{ "coredumpsize", login_getcapsize, RLIMIT_CORE },
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{ NULL, 0, 0 }
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};
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void
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setclassresources(login_cap_t *lc)
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{
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struct login_res *lr;
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if (lc == NULL)
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return;
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for (lr = resources; lr->what != NULL; ++lr) {
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struct rlimit rlim;
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/*
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* The login.conf file can have <limit>, <limit>-max, and
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* <limit>-cur entries.
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* What we do is get the current current- and maximum- limits.
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* Then, we try to get an entry for <limit> from the capability,
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* using the current and max limits we just got as the
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* default/error values.
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* *Then*, we try looking for <limit>-cur and <limit>-max,
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* again using the appropriate values as the default/error
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* conditions.
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*/
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if (getrlimit(lr->why, &rlim) != 0)
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syslog(LOG_ERR, "getting %s resource limit: %m", lr->what);
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else {
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char name_cur[40];
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char name_max[40];
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rlim_t rcur = rlim.rlim_cur;
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rlim_t rmax = rlim.rlim_max;
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sprintf(name_cur, "%s-cur", lr->what);
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sprintf(name_max, "%s-max", lr->what);
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rcur = (*lr->who)(lc, lr->what, rcur, rcur);
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rmax = (*lr->who)(lc, lr->what, rmax, rmax);
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rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur);
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rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax);
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if (setrlimit(lr->why, &rlim) == -1)
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syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what);
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}
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}
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}
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static struct login_vars {
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const char *tag;
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const char *var;
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const char *def;
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} pathvars[] = {
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{ "path", "PATH", NULL },
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{ "cdpath", "CDPATH", NULL },
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{ "manpath", "MANPATH", NULL },
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{ NULL, NULL, NULL }
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}, envars[] = {
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{ "lang", "LANG", NULL },
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{ "charset", "MM_CHARSET", NULL },
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{ "timezone", "TZ", NULL },
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{ "term", "TERM", UNKNOWN },
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{ NULL, NULL, NULL }
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};
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static char *
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substvar(char * var, const struct passwd * pwd, int hlen, int pch, int nlen)
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{
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char *np = NULL;
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if (var != NULL) {
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int tildes = 0;
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int dollas = 0;
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char *p;
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if (pwd != NULL) {
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/* Count the number of ~'s in var to substitute */
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p = var;
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for (p = var; (p = strchr(p, '~')) != NULL; p++)
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++tildes;
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/* Count the number of $'s in var to substitute */
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p = var;
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for (p = var; (p = strchr(p, '$')) != NULL; p++)
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++dollas;
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}
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np = malloc(strlen(var) + (dollas * nlen)
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- dollas + (tildes * (pch+hlen))
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- tildes + 1);
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if (np != NULL) {
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p = strcpy(np, var);
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if (pwd != NULL) {
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/*
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* This loop does user username and homedir substitutions
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* for unescaped $ (username) and ~ (homedir)
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*/
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while (*(p += strcspn(p, "~$")) != '\0') {
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int l = strlen(p);
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if (p > np && *(p-1) == '\\') /* Escaped: */
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memmove(p - 1, p, l + 1); /* Slide-out the backslash */
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else if (*p == '~') {
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int v = pch && *(p+1) != '/'; /* Avoid double // */
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memmove(p + hlen + v, p + 1, l); /* Subst homedir */
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memmove(p, pwd->pw_dir, hlen);
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if (v)
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p[hlen] = '/';
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p += hlen + v;
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}
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else /* if (*p == '$') */ {
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memmove(p + nlen, p + 1, l); /* Subst username */
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memmove(p, pwd->pw_name, nlen);
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p += nlen;
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}
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}
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}
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}
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}
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return np;
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}
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void
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setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths)
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{
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struct login_vars *vars = paths ? pathvars : envars;
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int hlen = pwd ? strlen(pwd->pw_dir) : 0;
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int nlen = pwd ? strlen(pwd->pw_name) : 0;
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char pch = 0;
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if (hlen && pwd->pw_dir[hlen-1] != '/')
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++pch;
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while (vars->tag != NULL) {
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char * var = paths ? login_getpath(lc, vars->tag, NULL)
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: login_getcapstr(lc, vars->tag, NULL, NULL);
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char * np = substvar(var, pwd, hlen, pch, nlen);
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if (np != NULL) {
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setenv(vars->var, np, 1);
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free(np);
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} else if (vars->def != NULL) {
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setenv(vars->var, vars->def, 0);
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}
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++vars;
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}
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/*
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* If we're not processing paths, then see if there is a setenv list by
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* which the admin and/or user may set an arbitrary set of env vars.
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*/
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if (!paths) {
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char **set_env = login_getcaplist(lc, "setenv", ",");
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if (set_env != NULL) {
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while (*set_env != NULL) {
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char *p = strchr(*set_env, '=');
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if (p != NULL) { /* Discard invalid entries */
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char *np;
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*p++ = '\0';
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if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) {
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setenv(*set_env, np, 1);
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free(np);
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}
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}
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++set_env;
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}
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}
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}
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}
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/*
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* setclasscontext()
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*
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* For the login class <class>, set various class context values
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* (limits, mainly) to the values for that class. Which values are
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* set are controlled by <flags> -- see <login_class.h> for the
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* possible values.
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*
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* setclasscontext() can only set resources, priority, and umask.
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*/
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int
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setclasscontext(const char *classname, unsigned int flags)
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{
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int rc;
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login_cap_t *lc;
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lc = login_getclassbyname(classname, NULL);
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flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY |
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LOGIN_SETUMASK | LOGIN_SETPATH;
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rc = lc ? setusercontext(lc, NULL, 0, flags) : -1;
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login_close(lc);
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return rc;
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}
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/*
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* Private functionw which takes care of processing
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*/
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static mode_t
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setlogincontext(login_cap_t *lc, const struct passwd *pwd,
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mode_t mymask, unsigned long flags)
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{
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if (lc) {
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/* Set resources */
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if (flags & LOGIN_SETRESOURCES)
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setclassresources(lc);
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/* See if there's a umask override */
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if (flags & LOGIN_SETUMASK)
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mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask);
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/* Set paths */
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if (flags & LOGIN_SETPATH)
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setclassenvironment(lc, pwd, 1);
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/* Set environment */
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if (flags & LOGIN_SETENV)
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setclassenvironment(lc, pwd, 0);
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}
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return mymask;
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}
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/*
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* setusercontext()
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*
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* Given a login class <lc> and a user in <pwd>, with a uid <uid>,
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* set the context as in setclasscontext(). <flags> controls which
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* values are set.
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*
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* The difference between setclasscontext() and setusercontext() is
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* that the former sets things up for an already-existing process,
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* while the latter sets things up from a root context. Such as might
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* be called from login(1).
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*
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*/
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int
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setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags)
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{
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quad_t p;
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mode_t mymask;
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login_cap_t *llc = NULL;
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#ifndef __NETBSD_SYSCALLS
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struct rtprio rtp;
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#endif
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if (lc == NULL) {
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if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL)
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llc = lc; /* free this when we're done */
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}
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if (flags & LOGIN_SETPATH)
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pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH;
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/* we need a passwd entry to set these */
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if (pwd == NULL)
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flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN);
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/* Set the process priority */
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if (flags & LOGIN_SETPRIORITY) {
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p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
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if(p > PRIO_MAX) {
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#ifndef __NETBSD_SYSCALLS
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rtp.type = RTP_PRIO_IDLE;
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rtp.prio = p - PRIO_MAX - 1;
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p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p;
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if(rtprio(RTP_SET, 0, &rtp))
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syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
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pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS);
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#endif
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} else if(p < PRIO_MIN) {
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#ifndef __NETBSD_SYSCALLS
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rtp.type = RTP_PRIO_REALTIME;
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rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX);
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p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p;
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if(rtprio(RTP_SET, 0, &rtp))
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syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
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pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS);
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#endif
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} else {
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if (setpriority(PRIO_PROCESS, 0, (int)p) != 0)
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syslog(LOG_WARNING, "setpriority '%s' (%s): %m",
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pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS);
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}
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}
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/* Setup the user's group permissions */
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if (flags & LOGIN_SETGROUP) {
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if (setgid(pwd->pw_gid) != 0) {
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syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid);
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login_close(llc);
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return -1;
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}
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if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
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syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name,
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(u_long)pwd->pw_gid);
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login_close(llc);
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return -1;
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}
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}
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/* Set the sessions login */
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if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) {
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syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name);
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login_close(llc);
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return -1;
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}
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mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0;
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mymask = setlogincontext(lc, pwd, mymask, flags);
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login_close(llc);
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/* This needs to be done after anything that needs root privs */
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if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) {
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syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid);
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return -1; /* Paranoia again */
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}
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/*
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* Now, we repeat some of the above for the user's private entries
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*/
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if ((lc = login_getuserclass(pwd)) != NULL) {
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mymask = setlogincontext(lc, pwd, mymask, flags);
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login_close(lc);
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}
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/* Finally, set any umask we've found */
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if (flags & LOGIN_SETUMASK)
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umask(mymask);
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return 0;
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}
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