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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#if HAVE_SELINUX
#include <selinux/selinux.h>
#endif
#include "sd-messages.h"
#include "initrd-util.h"
#include "log.h"
#include "macro.h"
#include "selinux-setup.h"
#include "selinux-util.h"
#include "string-util.h"
#include "time-util.h"
#if HAVE_SELINUX
_printf_(2,3)
static int null_log(int type, const char *fmt, ...) {
return 0;
}
#endif
int mac_selinux_setup(bool *loaded_policy) {
#if HAVE_SELINUX
int enforce = 0;
usec_t before_load, after_load;
char *con;
int r;
bool initialized;
assert(loaded_policy);
/* Turn off all of SELinux' own logging, we want to do that */
selinux_set_callback(SELINUX_CB_LOG, (const union selinux_callback) { .func_log = null_log });
/* Don't load policy in the initrd if we don't appear to have it. For the real root, we check below
* if we've already loaded policy, and return gracefully. */
if (in_initrd() && access(selinux_path(), F_OK) < 0)
return 0;
/* Already initialized by somebody else? */
r = getcon_raw(&con);
/* getcon_raw can return 0, and still give us a NULL pointer if /proc/self/attr/current is
* empty. SELinux guarantees this won't happen, but that file isn't specific to SELinux, and may be
* provided by some other arbitrary LSM with different semantics. */
if (r == 0 && con) {
initialized = !streq(con, "kernel");
freecon(con);
} else
initialized = false;
/* Make sure we have no fds open while loading the policy and
* transitioning */
log_close();
/* Now load the policy */
before_load = now(CLOCK_MONOTONIC);
r = selinux_init_load_policy(&enforce);
if (r == 0) {
_cleanup_(mac_selinux_freep) char *label = NULL;
mac_selinux_retest();
/* Transition to the new context */
r = mac_selinux_get_create_label_from_exe(SYSTEMD_BINARY_PATH, &label);
if (r < 0 || !label) {
log_open();
log_error("Failed to compute init label, ignoring.");
} else {
r = setcon_raw(label);
log_open();
if (r < 0)
log_error("Failed to transition into init label '%s', ignoring.", label);
}
after_load = now(CLOCK_MONOTONIC);
log_info("Successfully loaded SELinux policy in %s.",
FORMAT_TIMESPAN(after_load - before_load, 0));
*loaded_policy = true;
} else {
log_open();
if (enforce > 0) {
if (!initialized)
return log_struct_errno(LOG_EMERG, SYNTHETIC_ERRNO(EIO),
LOG_MESSAGE("Failed to load SELinux policy :%m"),
"MESSAGE_ID=" SD_MESSAGE_SELINUX_FAILED_STR);
log_warning("Failed to load new SELinux policy. Continuing with old policy.");
} else
log_debug("Unable to load SELinux policy. Ignoring.");
}
#endif
return 0;
}
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