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/*
* dpkg - main program for package management
* selinux.c - SELinux support
*
* Copyright © 2007-2015 Guillem Jover <guillem@debian.org>
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <compat.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <unistd.h>
#include <dpkg/i18n.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#ifdef WITH_LIBSELINUX
#include <selinux/selinux.h>
#include <selinux/avc.h>
#include <selinux/label.h>
#endif
#include "force.h"
#include "security-mac.h"
#ifdef WITH_LIBSELINUX
static struct selabel_handle *sehandle;
#endif
#ifdef WITH_LIBSELINUX
static int DPKG_ATTR_PRINTF(2)
log_callback(int type, const char *fmt, ...)
{
va_list ap;
char *msg;
switch (type) {
case SELINUX_ERROR:
case SELINUX_WARNING:
case SELINUX_AVC:
break;
default:
return 0;
}
va_start(ap, fmt);
m_vasprintf(&msg, fmt, ap);
va_end(ap);
warning("selinux: %s", msg);
free(msg);
return 0;
}
#endif
void
dpkg_selabel_load(void)
{
#ifdef WITH_LIBSELINUX
static int selinux_enabled = -1;
if (selinux_enabled < 0) {
int rc;
/* Set selinux_enabled if it is not already set (singleton). */
selinux_enabled = (in_force(FORCE_SECURITY_MAC) &&
is_selinux_enabled() > 0);
if (!selinux_enabled)
return;
/* Open the SELinux status notification channel, with fallback
* enabled for older kernels. */
rc = selinux_status_open(1);
if (rc < 0)
ohshit(_("cannot open security status notification channel"));
selinux_set_callback(SELINUX_CB_LOG, (union selinux_callback) {
.func_log = log_callback,
});
} else if (selinux_enabled && selinux_status_updated()) {
/* The SELinux policy got updated in the kernel, usually after
* upgrading the package shipping it, we need to reload. */
selabel_close(sehandle);
} else {
/* SELinux is either disabled or it does not need a reload. */
return;
}
sehandle = selabel_open(SELABEL_CTX_FILE, NULL, 0);
if (sehandle == NULL && security_getenforce() == 1)
ohshite(_("cannot get security labeling handle"));
#endif
}
void
dpkg_selabel_set_context(const char *matchpath, const char *path, mode_t mode)
{
#ifdef WITH_LIBSELINUX
char *scontext = NULL;
int ret;
/* If SELinux is not enabled just do nothing. */
if (sehandle == NULL)
return;
/*
* We use the _raw function variants here so that no translation
* happens from computer to human readable forms, to avoid issues
* when mcstransd has disappeared during the unpack process.
*/
/* Do nothing if we can't figure out what the context is, or if it has
* no context; in which case the default context shall be applied. */
ret = selabel_lookup_raw(sehandle, &scontext, matchpath, mode & S_IFMT);
if (ret < 0 || (ret == 0 && scontext == NULL))
return;
ret = lsetfilecon_raw(path, scontext);
if (ret < 0 && errno != ENOTSUP)
ohshite(_("cannot set security context for file object '%s'"),
path);
freecon(scontext);
#endif /* WITH_LIBSELINUX */
}
void
dpkg_selabel_close(void)
{
#ifdef WITH_LIBSELINUX
if (sehandle == NULL)
return;
selinux_status_close();
selabel_close(sehandle);
sehandle = NULL;
#endif
}
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