label.c revision c904f64d84db8c4eebedf210ba10893f19ba05ed
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd 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.
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <sys/stat.h>
#include <unistd.h>
#include "label.h"
#include "util.h"
#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#include <selinux/label.h>
static struct selabel_handle *label_hnd = NULL;
static inline bool use_selinux(void) {
static int use_selinux_ind = -1;
if (use_selinux_ind < 0)
use_selinux_ind = is_selinux_enabled() > 0;
return use_selinux_ind;
}
#endif
int label_init(void) {
int r = 0;
#ifdef HAVE_SELINUX
if (!use_selinux())
return 0;
if (label_hnd)
return 0;
label_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
if (!label_hnd) {
log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
"Failed to initialize SELinux context: %m");
r = security_getenforce() == 1 ? -errno : 0;
}
#endif
return r;
}
int label_fix(const char *path, bool ignore_enoent) {
int r = 0;
#ifdef HAVE_SELINUX
struct stat st;
security_context_t fcon;
if (!use_selinux() || !label_hnd)
return 0;
r = lstat(path, &st);
if (r == 0) {
r = selabel_lookup_raw(label_hnd, &fcon, path, st.st_mode);
/* If there's no label to set, then exit without warning */
if (r < 0 && errno == ENOENT)
return 0;
if (r == 0) {
r = setfilecon(path, fcon);
freecon(fcon);
/* If the FS doesn't support labels, then exit without warning */
if (r < 0 && errno == ENOTSUP)
return 0;
/* Ignore ENOENT in some cases */
if (r < 0 && ignore_enoent && errno == ENOENT)
return 0;
}
}
if (r < 0) {
log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
"Unable to fix label of %s: %m", path);
r = security_getenforce() == 1 ? -errno : 0;
}
#endif
return r;
}
void label_finish(void) {
#ifdef HAVE_SELINUX
if (use_selinux() && label_hnd)
selabel_close(label_hnd);
#endif
}
int label_get_socket_label_from_exe(const char *exe, char **label) {
int r = 0;
#ifdef HAVE_SELINUX
security_context_t mycon = NULL, fcon = NULL;
security_class_t sclass;
if (!use_selinux()) {
*label = NULL;
return 0;
}
r = getcon(&mycon);
if (r < 0)
goto fail;
r = getfilecon(exe, &fcon);
if (r < 0)
goto fail;
sclass = string_to_security_class("process");
r = security_compute_create(mycon, fcon, sclass, (security_context_t *) label);
if (r == 0)
log_debug("SELinux Socket context for %s will be set to %s", exe, *label);
fail:
if (r < 0 && security_getenforce() == 1)
r = -errno;
freecon(mycon);
freecon(fcon);
#endif
return r;
}
int label_fifofile_set(const char *path) {
int r = 0;
#ifdef HAVE_SELINUX
security_context_t filecon = NULL;
if (!use_selinux() || !label_hnd)
return 0;
if ((r = selabel_lookup_raw(label_hnd, &filecon, path, S_IFIFO)) == 0) {
if ((r = setfscreatecon(filecon)) < 0) {
log_error("Failed to set SELinux file context on %s: %m", path);
r = -errno;
}
freecon(filecon);
}
if (r < 0 && security_getenforce() == 0)
r = 0;
#endif
return r;
}
int label_symlinkfile_set(const char *path) {
int r = 0;
#ifdef HAVE_SELINUX
security_context_t filecon = NULL;
if (!use_selinux() || !label_hnd)
return 0;
if ((r = selabel_lookup_raw(label_hnd, &filecon, path, S_IFLNK)) == 0) {
if ((r = setfscreatecon(filecon)) < 0) {
log_error("Failed to set SELinux file context on %s: %m", path);
r = -errno;
}
freecon(filecon);
}
if (r < 0 && security_getenforce() == 0)
r = 0;
#endif
return r;
}
int label_socket_set(const char *label) {
#ifdef HAVE_SELINUX
if (!use_selinux())
return 0;
if (setsockcreatecon((security_context_t) label) < 0) {
log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
"Failed to set SELinux context (%s) on socket: %m", label);
if (security_getenforce() == 1)
return -errno;
}
#endif
return 0;
}
void label_file_clear(void) {
#ifdef HAVE_SELINUX
if (!use_selinux())
return;
setfscreatecon(NULL);
#endif
}
void label_socket_clear(void) {
#ifdef HAVE_SELINUX
if (!use_selinux())
return;
setsockcreatecon(NULL);
#endif
}
void label_free(const char *label) {
#ifdef HAVE_SELINUX
if (!use_selinux())
return;
freecon((security_context_t) label);
#endif
}
int label_mkdir(
const char *path,
mode_t mode) {
/* Creates a directory and labels it according to the SELinux policy */
#ifdef HAVE_SELINUX
int r;
security_context_t fcon = NULL;
if (use_selinux() && label_hnd) {
if (path_is_absolute(path))
r = selabel_lookup_raw(label_hnd, &fcon, path, mode);
else {
char *newpath = NULL;
if (!(newpath = path_make_absolute_cwd(path)))
return -ENOMEM;
r = selabel_lookup_raw(label_hnd, &fcon, newpath, mode);
free(newpath);
}
if (r == 0)
r = setfscreatecon(fcon);
if (r < 0 && errno != ENOENT) {
log_error("Failed to set security context %s for %s: %m", fcon, path);
r = -errno;
if (security_getenforce() == 1)
goto finish;
}
}
if ((r = mkdir(path, mode)) < 0)
r = -errno;
finish:
if (use_selinux() && label_hnd) {
setfscreatecon(NULL);
freecon(fcon);
}
return r;
#else
return mkdir(path, mode);
#endif
}