shadow/libmisc/env.c

244 lines
6.0 KiB
C
Raw Normal View History

/*
* Copyright 1989 - 1992, Julianne Frances Haugh
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, 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. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#include "rcsid.h"
RCSID ("$Id: env.c,v 1.11 2005/03/31 05:14:50 kloczek Exp $")
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "prototypes.h"
#include "defines.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;
char **newenvp = NULL;
extern char **environ;
static const char *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 *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, const char *value)
{
char *cp, *newstring;
size_t i;
size_t n;
if (value) {
newstring = xmalloc (strlen (string) + strlen (value) + 2);
sprintf (newstring, "%s=%s", string, value);
} 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 (!cp) {
free (newstring);
return;
}
n = (size_t) (cp - newstring);
for (i = 0; i < newenvc; i++) {
if (strncmp (newstring, newenvp[i], n) == 0 &&
(newenvp[i][n] == '=' || newenvp[i][n] == '\0'))
break;
}
if (i < newenvc) {
free (newenvp[i]);
newenvp[i] = newstring;
return;
}
newenvp[newenvc++] = newstring;
/*
* 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 succeds we can
* happily go on, else print a message.
*/
newsize = (newenvc + NEWENVP_STEP) * sizeof (char *);
__newenvp = (char **) realloc (newenvp, newsize);
if (__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 {
fprintf (stderr, _("Environment overflow\n"));
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 */
if (!(cp = strchr (*argv, '='))) {
snprintf (variable, sizeof variable, "L%d", noname++);
addenv (variable, *argv);
} else {
const char **p;
for (p = forbid; *p; p++)
if (strncmp (*argv, *p, strlen (*p)) == 0)
break;
if (*p) {
strncpy (variable, *argv, 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 **bad;
char **cur;
char **move;
for (cur = envp; *cur; cur++) {
for (bad = forbid; *bad; bad++) {
if (strncmp (*cur, *bad, strlen (*bad)) == 0) {
for (move = cur; *move; move++)
*move = *(move + 1);
cur--;
break;
}
}
}
for (cur = envp; *cur; cur++) {
for (bad = noslash; *bad; bad++) {
if (strncmp (*cur, *bad, strlen (*bad)) != 0)
continue;
if (!strchr (*cur, '/'))
continue; /* OK */
for (move = cur; *move; move++)
*move = *(move + 1);
cur--;
break;
}
}
}