ndhc/ncmlib/chroot.c
Nicholas J. Kain 7ab11e8295 Add strnkcpy() and strnkcat(). These are similar to strlcpy and strlcat,
but simply return a bool indicating whether the destination received
a truncated copy of the source (true if truncation occurs else false).

The change in return value semantics allows these functions to stop
scanning the source string early when truncation occurs, stopping the
program from scanning a possibly arbitrary-length source string.

I rarely use these return values in my own programs, so it won't be
very hard to bulk convert with no risk of regressions.

Further, the different namespace allows me to not depend on the presence
or absence of strlc(py|at) in the standard libraries.
2013-05-06 07:06:33 -04:00

125 lines
3.2 KiB
C

/* chroot.c - chroots ndyndns jobs
* Time-stamp: <2010-11-03 05:23:56 njk>
*
* (c) 2005-2010 Nicholas J. Kain <njkain at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 THE COPYRIGHT HOLDER 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 <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include "defines.h"
#include "log.h"
#include "strl.h"
static char chrootd[MAX_PATH_LENGTH] = "\0";
static char chroot_modified;
static char chroot_enable = 1;
void disable_chroot(void)
{
chroot_enable = 0;
}
int chroot_enabled(void)
{
return chroot_enable;
}
void update_chroot(const char *path)
{
strnkcpy(chrootd, path, sizeof chrootd);
chroot_modified = 1;
}
int chroot_exists(void)
{
return chroot_modified;
}
char *get_chroot(void)
{
return chrootd;
}
void wipe_chroot(void)
{
memset(chrootd, '\0', sizeof chrootd);
}
void imprison(const char *path)
{
int ret;
if (path == NULL)
return;
ret = chdir(path);
if (ret) {
log_line("Failed to chdir(%s). Not invoking job.", path);
exit(EXIT_FAILURE);
}
if (chroot_enable) {
ret = chroot(path);
if (ret) {
log_line("Failed to chroot(%s). Not invoking job.", path);
exit(EXIT_FAILURE);
}
}
}
void drop_root(uid_t uid, gid_t gid)
{
if (uid == 0 || gid == 0) {
log_line("FATAL - drop_root: attempt to drop root to root?\n");
exit(EXIT_FAILURE);
}
if (getgid() == 0) {
if (setregid(gid, gid) == -1) {
log_line("FATAL - drop_root: failed to drop real gid == root!\n");
exit(EXIT_FAILURE);
}
}
if (getuid() == 0) {
if (setreuid(uid, uid) == -1) {
log_line("FATAL - drop_root: failed to drop real uid == root!\n");
exit(EXIT_FAILURE);
}
}
/* be absolutely sure */
if (getgid() == 0 || getuid() == 0) {
log_line("FATAL - drop_root: tried to drop root, but still have root!\n");
exit(EXIT_FAILURE);
}
}