summaryrefslogtreecommitdiffstats
path: root/lib/selinux.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--lib/selinux.c210
1 files changed, 210 insertions, 0 deletions
diff --git a/lib/selinux.c b/lib/selinux.c
new file mode 100644
index 0000000..ad639bd
--- /dev/null
+++ b/lib/selinux.c
@@ -0,0 +1,210 @@
+/*
+ * SPDX-FileCopyrightText: 2011 , Peter Vrabec <pvrabec@redhat.com>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ifdef WITH_SELINUX
+
+#include <stdio.h>
+#include "defines.h"
+
+#include <selinux/selinux.h>
+#include <selinux/label.h>
+#include "prototypes.h"
+
+#include "shadowlog_internal.h"
+
+static bool selinux_checked = false;
+static bool selinux_enabled;
+static /*@null@*/struct selabel_handle *selabel_hnd = NULL;
+
+static void cleanup(void)
+{
+ if (selabel_hnd) {
+ selabel_close(selabel_hnd);
+ selabel_hnd = NULL;
+ }
+}
+
+void reset_selinux_handle (void)
+{
+ cleanup();
+}
+
+/*
+ * set_selinux_file_context - Set the security context before any file or
+ * directory creation.
+ *
+ * set_selinux_file_context () should be called before any creation
+ * of file, symlink, directory, ...
+ *
+ * Callers may have to Reset SELinux to create files with default
+ * contexts with reset_selinux_file_context
+ */
+int set_selinux_file_context (const char *dst_name, mode_t mode)
+{
+ if (!selinux_checked) {
+ selinux_enabled = is_selinux_enabled () > 0;
+ selinux_checked = true;
+ }
+
+ if (selinux_enabled) {
+ /* Get the default security context for this file */
+
+ /*@null@*/char *fcontext_raw = NULL;
+ int r;
+
+ if (selabel_hnd == NULL) {
+ selabel_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
+ if (selabel_hnd == NULL) {
+ return security_getenforce () != 0;
+ }
+ (void) atexit(cleanup);
+ }
+
+ r = selabel_lookup_raw(selabel_hnd, &fcontext_raw, dst_name, mode);
+ if (r < 0) {
+ /* No context specified for the searched path */
+ if (errno == ENOENT) {
+ return 0;
+ }
+
+ return security_getenforce () != 0;
+ }
+
+ /* Set the security context for the next created file */
+ r = setfscreatecon_raw (fcontext_raw);
+ freecon (fcontext_raw);
+ if (r < 0) {
+ return security_getenforce () != 0;
+ }
+ }
+ return 0;
+}
+
+/*
+ * reset_selinux_file_context - Reset the security context to the default
+ * policy behavior
+ *
+ * reset_selinux_file_context () should be called after the context
+ * was changed with set_selinux_file_context ()
+ */
+int reset_selinux_file_context (void)
+{
+ if (!selinux_checked) {
+ selinux_enabled = is_selinux_enabled () > 0;
+ selinux_checked = true;
+ }
+ if (selinux_enabled) {
+ if (setfscreatecon_raw (NULL) != 0) {
+ return security_getenforce () != 0;
+ }
+ }
+ return 0;
+}
+
+/*
+ * Log callback for libselinux internal error reporting.
+ */
+format_attr(printf, 2, 3)
+static int selinux_log_cb (int type, const char *fmt, ...) {
+ va_list ap;
+ char *buf;
+ int r;
+#ifdef WITH_AUDIT
+ static int selinux_audit_fd = -2;
+#endif
+
+ va_start (ap, fmt);
+ r = vasprintf (&buf, fmt, ap);
+ va_end (ap);
+
+ if (r < 0) {
+ return 0;
+ }
+
+#ifdef WITH_AUDIT
+ if (-2 == selinux_audit_fd) {
+ selinux_audit_fd = audit_open ();
+
+ if (-1 == selinux_audit_fd) {
+ /* You get these only when the kernel doesn't have
+ * audit compiled in. */
+ if ( (errno != EINVAL)
+ && (errno != EPROTONOSUPPORT)
+ && (errno != EAFNOSUPPORT)) {
+
+ (void) fputs (_("Cannot open audit interface.\n"),
+ shadow_logfd);
+ SYSLOG ((LOG_WARN, "Cannot open audit interface."));
+ }
+ }
+ }
+
+ if (-1 != selinux_audit_fd) {
+ if (SELINUX_AVC == type) {
+ if (audit_log_user_avc_message (selinux_audit_fd,
+ AUDIT_USER_AVC, buf, NULL, NULL,
+ NULL, 0) > 0) {
+ goto skip_syslog;
+ }
+ } else if (SELINUX_ERROR == type) {
+ if (audit_log_user_avc_message (selinux_audit_fd,
+ AUDIT_USER_SELINUX_ERR, buf, NULL, NULL,
+ NULL, 0) > 0) {
+ goto skip_syslog;
+ }
+ }
+ }
+#endif
+
+ SYSLOG ((LOG_WARN, "libselinux: %s", buf));
+
+skip_syslog:
+ free (buf);
+
+ return 0;
+}
+
+/*
+ * check_selinux_permit - Check whether SELinux grants the given
+ * operation
+ *
+ * Parameter is the SELinux permission name, e.g. rootok
+ *
+ * Returns 0 when permission is granted
+ * or something failed but running in
+ * permissive mode
+ */
+int check_selinux_permit (const char *perm_name)
+{
+ char *user_context_raw;
+ int r;
+
+ if (0 == is_selinux_enabled ()) {
+ return 0;
+ }
+
+ selinux_set_callback (SELINUX_CB_LOG, (union selinux_callback) selinux_log_cb);
+
+ if (getprevcon_raw (&user_context_raw) != 0) {
+ fprintf (shadow_logfd,
+ _("%s: can not get previous SELinux process context: %s\n"),
+ shadow_progname, strerror (errno));
+ SYSLOG ((LOG_WARN,
+ "can not get previous SELinux process context: %s",
+ strerror (errno)));
+ return (security_getenforce () != 0);
+ }
+
+ r = selinux_check_access (user_context_raw, user_context_raw, "passwd", perm_name, NULL);
+ freecon (user_context_raw);
+ return r;
+}
+
+#else /* !WITH_SELINUX */
+extern int errno; /* warning: ANSI C forbids an empty source file */
+#endif /* !WITH_SELINUX */