1 files changed, 106 insertions, 0 deletions
diff --git a/src/core/selinux-setup.c b/src/core/selinux-setup.c
new file mode 100644
index 0000000..bc1a249
--- /dev/null
+++ b/src/core/selinux-setup.c
@@ -0,0 +1,106 @@
+/* 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;
+}