freebsd-dev/lib/libutil/login_cap.c
Peter Wemm 05bcd1d098 (mostly) Clean up some const warnings here. The code takes some liberties
because it is the originator of various const strings and knows that they
came from malloc.
2003-10-26 03:51:47 +00:00

808 lines
19 KiB
C

/*-
* 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 (ie. "default") is fetched. If the
* 'dir' argument contains a non-NULL non-empty string,
* then the file _FILE_LOGIN_CONF is picked up from that
* directory instead of the system login database.
* 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 */
}
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_getclass()
* 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 (ie. "default").
* 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;
}
return login_getclassbyname(cls, pwd);
}
/*
* login_getuserclass()
* Get the login class for a given password entry, allowing user
* overrides via ~/.login_conf.
*/
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 defualt 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;
}