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freebsd-dev/lib/libutil/login_cap.c

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/*-
* Copyright (c) 1996 by
* Sean Eric Fagan <sef@kithrup.com>
* David Nugent <davidn@blaze.net.au>
* All rights reserved.
*
* Portions copyright (c) 1995,1997
* Berkeley Software Design, Inc.
* 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.
*
* Low-level routines relating to the user capabilities database
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/param.h>
#include <errno.h>
#include <fcntl.h>
#include <libutil.h>
#include <login_cap.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
/*
* allocstr()
* Manage a single static pointer for handling a local char* buffer,
* resizing as necessary to contain the string.
*
* allocarray()
* Manage a static array for handling a group of strings, resizing
* when necessary.
*/
static int lc_object_count = 0;
static size_t internal_stringsz = 0;
static char * internal_string = NULL;
static size_t internal_arraysz = 0;
static const char ** internal_array = NULL;
static char *
allocstr(const char *str)
{
char *p;
size_t sz = strlen(str) + 1; /* realloc() only if necessary */
if (sz <= internal_stringsz)
p = strcpy(internal_string, str);
else if ((p = realloc(internal_string, sz)) != NULL) {
internal_stringsz = sz;
internal_string = strcpy(p, str);
}
return p;
}
static const char **
allocarray(size_t sz)
{
static const char **p;
if (sz <= internal_arraysz)
p = internal_array;
else if ((p = realloc(internal_array, sz * sizeof(char*))) != NULL) {
internal_arraysz = sz;
internal_array = p;
}
return p;
}
/*
* arrayize()
* Turn a simple string <str> separated by any of
* the set of <chars> into an array. The last element
* of the array will be NULL, as is proper.
* Free using freearraystr()
*/
static const char **
arrayize(const char *str, const char *chars, int *size)
{
int i;
char *ptr;
const char *cptr;
const char **res = NULL;
/* count the sub-strings */
for (i = 0, cptr = str; *cptr; i++) {
int count = strcspn(cptr, chars);
cptr += count;
if (*cptr)
++cptr;
}
/* alloc the array */
if ((ptr = allocstr(str)) != NULL) {
if ((res = allocarray(++i)) == NULL)
free((void *)(uintptr_t)(const void *)str);
else {
/* now split the string */
i = 0;
while (*ptr) {
int count = strcspn(ptr, chars);
res[i++] = ptr;
ptr += count;
if (*ptr)
*ptr++ = '\0';
}
res[i] = NULL;
}
}
if (size)
*size = i;
return res;
}
/*
* login_close()
* Frees up all resources relating to a login class
*
*/
void
login_close(login_cap_t * lc)
{
if (lc) {
free(lc->lc_style);
free(lc->lc_class);
free(lc->lc_cap);
free(lc);
if (--lc_object_count == 0) {
free(internal_string);
free(internal_array);
internal_array = NULL;
internal_arraysz = 0;
internal_string = NULL;
internal_stringsz = 0;
cgetclose();
}
}
}
/*
* login_getclassbyname()
* Get the login class by its name.
* If the name given is NULL or empty, the default class
* LOGIN_DEFCLASS (i.e., "default") is fetched.
* If the name given is LOGIN_MECLASS and
* 'pwd' argument is non-NULL and contains an non-NULL
* dir entry, then the file _FILE_LOGIN_CONF is picked
* up from that directory and used before the system
* login database. In that case the system login database
* is looked up using LOGIN_MECLASS, too, which is a bug.
* Return a filled-out login_cap_t structure, including
* class name, and the capability record buffer.
*/
login_cap_t *
login_getclassbyname(char const *name, const struct passwd *pwd)
{
login_cap_t *lc;
if ((lc = malloc(sizeof(login_cap_t))) != NULL) {
int r, me, i = 0;
uid_t euid = 0;
gid_t egid = 0;
const char *msg = NULL;
const char *dir;
char userpath[MAXPATHLEN];
static char *login_dbarray[] = { NULL, NULL, NULL };
me = (name != NULL && strcmp(name, LOGIN_MECLASS) == 0);
dir = (!me || pwd == NULL) ? NULL : pwd->pw_dir;
/*
* Switch to user mode before checking/reading its ~/.login_conf
* - some NFSes have root read access disabled.
*
* XXX: This fails to configure additional groups.
*/
if (dir) {
euid = geteuid();
egid = getegid();
(void)setegid(pwd->pw_gid);
(void)seteuid(pwd->pw_uid);
}
if (dir && snprintf(userpath, MAXPATHLEN, "%s/%s", dir,
_FILE_LOGIN_CONF) < MAXPATHLEN) {
login_dbarray[i] = userpath;
if (_secure_path(userpath, pwd->pw_uid, pwd->pw_gid) != -1)
i++; /* only use 'secure' data */
}
/*
* XXX: Why to add the system database if the class is `me'?
*/
if (_secure_path(_PATH_LOGIN_CONF, 0, 0) != -1)
login_dbarray[i++] = _PATH_LOGIN_CONF;
login_dbarray[i] = NULL;
memset(lc, 0, sizeof(login_cap_t));
lc->lc_cap = lc->lc_class = lc->lc_style = NULL;
if (name == NULL || *name == '\0')
name = LOGIN_DEFCLASS;
switch (cgetent(&lc->lc_cap, login_dbarray, name)) {
case -1: /* Failed, entry does not exist */
if (me)
break; /* Don't retry default on 'me' */
if (i == 0)
r = -1;
else if ((r = open(login_dbarray[0], O_RDONLY)) >= 0)
close(r);
/*
* If there's at least one login class database,
* and we aren't searching for a default class
* then complain about a non-existent class.
*/
if (r >= 0 || strcmp(name, LOGIN_DEFCLASS) != 0)
syslog(LOG_ERR, "login_getclass: unknown class '%s'", name);
/* fall-back to default class */
name = LOGIN_DEFCLASS;
msg = "%s: no default/fallback class '%s'";
if (cgetent(&lc->lc_cap, login_dbarray, name) != 0 && r >= 0)
break;
/* FALLTHROUGH - just return system defaults */
case 0: /* success! */
if ((lc->lc_class = strdup(name)) != NULL) {
if (dir) {
(void)seteuid(euid);
(void)setegid(egid);
}
++lc_object_count;
return lc;
}
msg = "%s: strdup: %m";
break;
case -2:
msg = "%s: retrieving class information: %m";
break;
case -3:
msg = "%s: 'tc=' reference loop '%s'";
break;
case 1:
msg = "couldn't resolve 'tc=' reference in '%s'";
break;
default:
msg = "%s: unexpected cgetent() error '%s': %m";
break;
}
if (dir) {
(void)seteuid(euid);
(void)setegid(egid);
}
if (msg != NULL)
syslog(LOG_ERR, msg, "login_getclass", name);
free(lc);
}
return NULL;
}
/*
* login_getclass()
* Get the login class for the system (only) login class database.
* Return a filled-out login_cap_t structure, including
* class name, and the capability record buffer.
*/
login_cap_t *
login_getclass(const char *cls)
{
return login_getclassbyname(cls, NULL);
}
/*
* login_getpwclass()
* Get the login class for a given password entry from
* the system (only) login class database.
* If the password entry's class field is not set, or
* the class specified does not exist, then use the
* default of LOGIN_DEFCLASS (i.e., "default") for an unprivileged
* user or that of LOGIN_DEFROOTCLASS (i.e., "root") for a super-user.
* Return a filled-out login_cap_t structure, including
* class name, and the capability record buffer.
*/
login_cap_t *
login_getpwclass(const struct passwd *pwd)
{
const char *cls = NULL;
if (pwd != NULL) {
cls = pwd->pw_class;
if (cls == NULL || *cls == '\0')
cls = (pwd->pw_uid == 0) ? LOGIN_DEFROOTCLASS : LOGIN_DEFCLASS;
}
/*
* XXX: pwd should be unused by login_getclassbyname() unless cls is `me',
* so NULL can be passed instead of pwd for more safety.
*/
return login_getclassbyname(cls, pwd);
}
/*
* login_getuserclass()
* Get the `me' login class, allowing user overrides via ~/.login_conf.
* Note that user overrides are allowed only in the `me' class.
*/
login_cap_t *
login_getuserclass(const struct passwd *pwd)
{
return login_getclassbyname(LOGIN_MECLASS, pwd);
}
/*
* login_getcapstr()
* Given a login_cap entry, and a capability name, return the
* value defined for that capability, a default if not found, or
* an error string on error.
*/
const char *
login_getcapstr(login_cap_t *lc, const char *cap, const char *def, const char *error)
{
char *res;
int ret;
if (lc == NULL || cap == NULL || lc->lc_cap == NULL || *cap == '\0')
return def;
if ((ret = cgetstr(lc->lc_cap, cap, &res)) == -1)
return def;
return (ret >= 0) ? res : error;
}
/*
* login_getcaplist()
* Given a login_cap entry, and a capability name, return the
* value defined for that capability split into an array of
* strings.
*/
const char **
login_getcaplist(login_cap_t *lc, const char *cap, const char *chars)
{
const char *lstring;
if (chars == NULL)
chars = ", \t";
if ((lstring = login_getcapstr(lc, cap, NULL, NULL)) != NULL)
return arrayize(lstring, chars, NULL);
return NULL;
}
/*
* login_getpath()
* From the login_cap_t <lc>, get the capability <cap> which is
* formatted as either a space or comma delimited list of paths
* and append them all into a string and separate by semicolons.
* If there is an error of any kind, return <error>.
*/
const char *
login_getpath(login_cap_t *lc, const char *cap, const char *error)
{
const char *str;
char *ptr;
int count;
str = login_getcapstr(lc, cap, NULL, NULL);
if (str == NULL)
return error;
ptr = __DECONST(char *, str); /* XXXX Yes, very dodgy */
while (*ptr) {
count = strcspn(ptr, ", \t");
ptr += count;
if (*ptr)
*ptr++ = ':';
}
return str;
}
static int
isinfinite(const char *s)
{
static const char *infs[] = {
"infinity",
"inf",
"unlimited",
"unlimit",
"-1",
NULL
};
const char **i = &infs[0];
while (*i != NULL) {
if (strcasecmp(s, *i) == 0)
return 1;
++i;
}
return 0;
}
static u_quad_t
rmultiply(u_quad_t n1, u_quad_t n2)
{
u_quad_t m, r;
int b1, b2;
static int bpw = 0;
/* Handle simple cases */
if (n1 == 0 || n2 == 0)
return 0;
if (n1 == 1)
return n2;
if (n2 == 1)
return n1;
/*
* sizeof() returns number of bytes needed for storage.
* This may be different from the actual number of useful bits.
*/
if (!bpw) {
bpw = sizeof(u_quad_t) * 8;
while (((u_quad_t)1 << (bpw-1)) == 0)
--bpw;
}
/*
* First check the magnitude of each number. If the sum of the
* magnatude is way to high, reject the number. (If this test
* is not done then the first multiply below may overflow.)
*/
for (b1 = bpw; (((u_quad_t)1 << (b1-1)) & n1) == 0; --b1)
;
for (b2 = bpw; (((u_quad_t)1 << (b2-1)) & n2) == 0; --b2)
;
if (b1 + b2 - 2 > bpw) {
errno = ERANGE;
return (UQUAD_MAX);
}
/*
* Decompose the multiplication to be:
* h1 = n1 & ~1
* h2 = n2 & ~1
* l1 = n1 & 1
* l2 = n2 & 1
* (h1 + l1) * (h2 + l2)
* (h1 * h2) + (h1 * l2) + (l1 * h2) + (l1 * l2)
*
* Since h1 && h2 do not have the low bit set, we can then say:
*
* (h1>>1 * h2>>1 * 4) + ...
*
* So if (h1>>1 * h2>>1) > (1<<(bpw - 2)) then the result will
* overflow.
*
* Finally, if MAX - ((h1 * l2) + (l1 * h2) + (l1 * l2)) < (h1*h2)
* then adding in residual amout will cause an overflow.
*/
m = (n1 >> 1) * (n2 >> 1);
if (m >= ((u_quad_t)1 << (bpw-2))) {
errno = ERANGE;
return (UQUAD_MAX);
}
m *= 4;
r = (n1 & n2 & 1)
+ (n2 & 1) * (n1 & ~(u_quad_t)1)
+ (n1 & 1) * (n2 & ~(u_quad_t)1);
if ((u_quad_t)(m + r) < m) {
errno = ERANGE;
return (UQUAD_MAX);
}
m += r;
return (m);
}
/*
* login_getcaptime()
* From the login_cap_t <lc>, get the capability <cap>, which is
* formatted as a time (e.g., "<cap>=10h3m2s"). If <cap> is not
* present in <lc>, return <def>; if there is an error of some kind,
* return <error>.
*/
rlim_t
login_getcaptime(login_cap_t *lc, const char *cap, rlim_t def, rlim_t error)
{
char *res, *ep, *oval;
int r;
rlim_t tot;
errno = 0;
if (lc == NULL || lc->lc_cap == NULL)
return def;
/*
* Look for <cap> in lc_cap.
* If it's not there (-1), return <def>.
* If there's an error, return <error>.
*/
if ((r = cgetstr(lc->lc_cap, cap, &res)) == -1)
return def;
else if (r < 0) {
errno = ERANGE;
return error;
}
/* "inf" and "infinity" are special cases */
if (isinfinite(res))
return RLIM_INFINITY;
/*
* Now go through the string, turning something like 1h2m3s into
* an integral value. Whee.
*/
errno = 0;
tot = 0;
oval = res;
while (*res) {
rlim_t tim = strtoq(res, &ep, 0);
rlim_t mult = 1;
if (ep == NULL || ep == res || errno != 0) {
invalid:
syslog(LOG_WARNING, "login_getcaptime: class '%s' bad value %s=%s",
lc->lc_class, cap, oval);
errno = ERANGE;
return error;
}
/* Look for suffixes */
switch (*ep++) {
case 0:
ep--;
break; /* end of string */
case 's': case 'S': /* seconds */
break;
case 'm': case 'M': /* minutes */
mult = 60;
break;
case 'h': case 'H': /* hours */
mult = 60L * 60L;
break;
case 'd': case 'D': /* days */
mult = 60L * 60L * 24L;
break;
case 'w': case 'W': /* weeks */
mult = 60L * 60L * 24L * 7L;
break;
case 'y': case 'Y': /* 365-day years */
mult = 60L * 60L * 24L * 365L;
break;
default:
goto invalid;
}
res = ep;
tot += rmultiply(tim, mult);
if (errno)
goto invalid;
}
return tot;
}
/*
* login_getcapnum()
* From the login_cap_t <lc>, extract the numerical value <cap>.
* If it is not present, return <def> for a default, and return
* <error> if there is an error.
* Like login_getcaptime(), only it only converts to a number, not
* to a time; "infinity" and "inf" are 'special.'
*/
rlim_t
login_getcapnum(login_cap_t *lc, const char *cap, rlim_t def, rlim_t error)
{
char *ep, *res;
int r;
rlim_t val;
if (lc == NULL || lc->lc_cap == NULL)
return def;
/*
* For BSDI compatibility, try for the tag=<val> first
*/
if ((r = cgetstr(lc->lc_cap, cap, &res)) == -1) {
long lval;
/* string capability not present, so try for tag#<val> as numeric */
if ((r = cgetnum(lc->lc_cap, cap, &lval)) == -1)
return def; /* Not there, so return default */
else if (r >= 0)
return (rlim_t)lval;
}
if (r < 0) {
errno = ERANGE;
return error;
}
if (isinfinite(res))
return RLIM_INFINITY;
errno = 0;
val = strtoq(res, &ep, 0);
if (ep == NULL || ep == res || errno != 0) {
syslog(LOG_WARNING, "login_getcapnum: class '%s' bad value %s=%s",
lc->lc_class, cap, res);
errno = ERANGE;
return error;
}
return val;
}
/*
* login_getcapsize()
* From the login_cap_t <lc>, extract the capability <cap>, which is
* formatted as a size (e.g., "<cap>=10M"); it can also be "infinity".
* If not present, return <def>, or <error> if there is an error of
* some sort.
*/
rlim_t
login_getcapsize(login_cap_t *lc, const char *cap, rlim_t def, rlim_t error)
{
char *ep, *res, *oval;
int r;
rlim_t tot;
if (lc == NULL || lc->lc_cap == NULL)
return def;
if ((r = cgetstr(lc->lc_cap, cap, &res)) == -1)
return def;
else if (r < 0) {
errno = ERANGE;
return error;
}
if (isinfinite(res))
return RLIM_INFINITY;
errno = 0;
tot = 0;
oval = res;
while (*res) {
rlim_t siz = strtoq(res, &ep, 0);
rlim_t mult = 1;
if (ep == NULL || ep == res || errno != 0) {
invalid:
syslog(LOG_WARNING, "login_getcapsize: class '%s' bad value %s=%s",
lc->lc_class, cap, oval);
errno = ERANGE;
return error;
}
switch (*ep++) {
case 0: /* end of string */
ep--;
break;
case 'b': case 'B': /* 512-byte blocks */
mult = 512;
break;
case 'k': case 'K': /* 1024-byte Kilobytes */
mult = 1024;
break;
case 'm': case 'M': /* 1024-k kbytes */
mult = 1024 * 1024;
break;
case 'g': case 'G': /* 1Gbyte */
mult = 1024 * 1024 * 1024;
break;
case 't': case 'T': /* 1TBte */
mult = 1024LL * 1024LL * 1024LL * 1024LL;
break;
default:
goto invalid;
}
res = ep;
tot += rmultiply(siz, mult);
if (errno)
goto invalid;
}
return tot;
}
/*
* login_getcapbool()
* From the login_cap_t <lc>, check for the existance of the capability
* of <cap>. Return <def> if <lc>->lc_cap is NULL, otherwise return
* the whether or not <cap> exists there.
*/
int
login_getcapbool(login_cap_t *lc, const char *cap, int def)
{
if (lc == NULL || lc->lc_cap == NULL)
return def;
return (cgetcap(lc->lc_cap, cap, ':') != NULL);
}
/*
* login_getstyle()
* Given a login_cap entry <lc>, and optionally a type of auth <auth>,
* and optionally a style <style>, find the style that best suits these
* rules:
* 1. If <auth> is non-null, look for an "auth-<auth>=" string
* in the capability; if not present, default to "auth=".
* 2. If there is no auth list found from (1), default to
* "passwd" as an authorization list.
* 3. If <style> is non-null, look for <style> in the list of
* authorization methods found from (2); if <style> is NULL, default
* to LOGIN_DEFSTYLE ("passwd").
* 4. If the chosen style is found in the chosen list of authorization
* methods, return that; otherwise, return NULL.
* E.g.:
* login_getstyle(lc, NULL, "ftp");
* login_getstyle(lc, "login", NULL);
* login_getstyle(lc, "skey", "network");
*/
const char *
login_getstyle(login_cap_t *lc, const char *style, const char *auth)
{
int i;
const char **authtypes = NULL;
char *auths= NULL;
char realauth[64];
static const char *defauthtypes[] = { LOGIN_DEFSTYLE, NULL };
if (auth != NULL && *auth != '\0') {
if (snprintf(realauth, sizeof realauth, "auth-%s", auth) < (int)sizeof(realauth))
authtypes = login_getcaplist(lc, realauth, NULL);
}
if (authtypes == NULL)
authtypes = login_getcaplist(lc, "auth", NULL);
if (authtypes == NULL)
authtypes = defauthtypes;
/*
* We have at least one authtype now; auths is a comma-separated
* (or space-separated) list of authentication types. We have to
* convert from this to an array of char*'s; authtypes then gets this.
*/
i = 0;
if (style != NULL && *style != '\0') {
while (authtypes[i] != NULL && strcmp(style, authtypes[i]) != 0)
i++;
}
lc->lc_style = NULL;
if (authtypes[i] != NULL && (auths = strdup(authtypes[i])) != NULL)
lc->lc_style = auths;
if (lc->lc_style != NULL)
lc->lc_style = strdup(lc->lc_style);
return lc->lc_style;
}
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