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/*
* SPDX-FileCopyrightText: 1989 - 1992, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 1999, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2008 - 2009, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ident "$Id$"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "prototypes.h"
#include "defines.h"
#include "shadowlog.h"
/*
* NEWENVP_STEP must be a power of two. This is the number
* of (char *) pointers to allocate at a time, to avoid using
* realloc() too often.
*/
#define NEWENVP_STEP 16
size_t newenvc = 0;
/*@null@*/char **newenvp = NULL;
extern char **environ;
static const char *const forbid[] = {
"_RLD_=",
"BASH_ENV=", /* GNU creeping featurism strikes again... */
"ENV=",
"HOME=",
"IFS=",
"KRB_CONF=",
"LD_", /* anything with the LD_ prefix */
"LIBPATH=",
"MAIL=",
"NLSPATH=",
"PATH=",
"SHELL=",
"SHLIB_PATH=",
(char *) 0
};
/* these are allowed, but with no slashes inside
(to work around security problems in GNU gettext) */
static const char *const noslash[] = {
"LANG=",
"LANGUAGE=",
"LC_", /* anything with the LC_ prefix */
(char *) 0
};
/*
* initenv() must be called once before using addenv().
*/
void initenv (void)
{
newenvp = (char **) xmalloc (NEWENVP_STEP * sizeof (char *));
*newenvp = NULL;
}
void addenv (const char *string, /*@null@*/const char *value)
{
char *cp, *newstring;
size_t i;
size_t n;
if (NULL != value) {
size_t len = strlen (string) + strlen (value) + 2;
int wlen;
newstring = xmalloc (len);
wlen = snprintf (newstring, len, "%s=%s", string, value);
assert (wlen == (int) len -1);
} else {
newstring = xstrdup (string);
}
/*
* Search for a '=' character within the string and if none is found
* just ignore the whole string.
*/
cp = strchr (newstring, '=');
if (NULL == cp) {
free (newstring);
return;
}
n = (size_t) (cp - newstring);
/*
* If this environment variable is already set, change its value.
*/
for (i = 0; i < newenvc; i++) {
if ( (strncmp (newstring, newenvp[i], n) == 0)
&& (('=' == newenvp[i][n]) || ('\0' == newenvp[i][n]))) {
break;
}
}
if (i < newenvc) {
free (newenvp[i]);
newenvp[i] = newstring;
return;
}
/*
* Otherwise, save the new environment variable
*/
newenvp[newenvc++] = newstring;
/*
* And extend the environment if needed.
*/
/*
* Check whether newenvc is a multiple of NEWENVP_STEP.
* If so we have to resize the vector.
* the expression (newenvc & (NEWENVP_STEP - 1)) == 0
* is equal to (newenvc % NEWENVP_STEP) == 0
* as long as NEWENVP_STEP is a power of 2.
*/
if ((newenvc & (NEWENVP_STEP - 1)) == 0) {
char **__newenvp;
size_t newsize;
/*
* If the resize operation succeeds we can
* happily go on, else print a message.
*/
newsize = (newenvc + NEWENVP_STEP) * sizeof (char *);
__newenvp = (char **) realloc (newenvp, newsize);
if (NULL != __newenvp) {
/*
* If this is our current environment, update
* environ so that it doesn't point to some
* free memory area (realloc() could move it).
*/
if (environ == newenvp) {
environ = __newenvp;
}
newenvp = __newenvp;
} else {
(void) fputs (_("Environment overflow\n"), log_get_logfd());
newenvc--;
free (newenvp[newenvc]);
}
}
/*
* The last entry of newenvp must be NULL
*/
newenvp[newenvc] = NULL;
}
/*
* set_env - copy command line arguments into the environment
*/
void set_env (int argc, char *const *argv)
{
int noname = 1;
char variable[1024];
char *cp;
for (; argc > 0; argc--, argv++) {
if (strlen (*argv) >= sizeof variable) {
continue; /* ignore long entries */
}
cp = strchr (*argv, '=');
if (NULL == cp) {
int wlen;
wlen = snprintf (variable, sizeof variable, "L%d", noname);
assert (wlen < (int) sizeof(variable));
noname++;
addenv (variable, *argv);
} else {
const char *const *p;
for (p = forbid; NULL != *p; p++) {
if (strncmp (*argv, *p, strlen (*p)) == 0) {
break;
}
}
if (NULL != *p) {
strncpy (variable, *argv, (size_t)(cp - *argv));
variable[cp - *argv] = '\0';
printf (_("You may not change $%s\n"),
variable);
continue;
}
addenv (*argv, NULL);
}
}
}
/*
* sanitize_env - remove some nasty environment variables
* If you fall into a total paranoia, you should call this
* function for any root-setuid program or anything the user
* might change the environment with. 99% useless as almost
* all modern Unixes will handle setuid executables properly,
* but... I feel better with that silly precaution. -j.
*/
void sanitize_env (void)
{
char **envp = environ;
const char *const *bad;
char **cur;
char **move;
for (cur = envp; NULL != *cur; cur++) {
for (bad = forbid; NULL != *bad; bad++) {
if (strncmp (*cur, *bad, strlen (*bad)) == 0) {
for (move = cur; NULL != *move; move++) {
*move = *(move + 1);
}
cur--;
break;
}
}
}
for (cur = envp; NULL != *cur; cur++) {
for (bad = noslash; NULL != *bad; bad++) {
if (strncmp (*cur, *bad, strlen (*bad)) != 0) {
continue;
}
if (strchr (*cur, '/') == NULL) {
continue; /* OK */
}
for (move = cur; NULL != *move; move++) {
*move = *(move + 1);
}
cur--;
break;
}
}
}
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