1 files changed, 85 insertions, 0 deletions
diff --git a/lib/selinux-utils.c b/lib/selinux-utils.c
new file mode 100644
index 0000000..c0df891
--- /dev/null
+++ b/lib/selinux-utils.c
@@ -0,0 +1,85 @@
+/*
+ * No copyright is claimed.  This code is in the public domain; do with
+ * it what you wish.
+ *
+ * Written by Karel Zak <kzak@redhat.com> [January 2021]
+ */
+#include <selinux/context.h>
+#include <selinux/selinux.h>
+#include <selinux/label.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <errno.h>
+
+#include "selinux-utils.h"
+
+/* set the SELinux security context used for _creating_ a new file system object
+ *
+ * returns 0 on success,
+ *     or <0 on error
+ */
+int ul_setfscreatecon_from_file(char *orig_file)
+{
+	if (is_selinux_enabled() > 0) {
+		char *scontext = NULL;
+
+		if (getfilecon(orig_file, &scontext) < 0)
+			return -1;
+		if (setfscreatecon(scontext) < 0) {
+			freecon(scontext);
+			return -1;
+		}
+		freecon(scontext);
+	}
+	return 0;
+}
+
+/* returns 1 if user has access to @class and @perm ("passwd", "chfn")
+ *	or 0 on error,
+ *	or 0 if has no access -- in this case sets @user_cxt to user-context
+ */
+int ul_selinux_has_access(const char *classstr, const char *perm, char **user_cxt)
+{
+	char *user;
+	int rc;
+
+	if (user_cxt)
+		*user_cxt = NULL;
+
+	if (getprevcon(&user) != 0)
+		return 0;
+
+	rc = selinux_check_access(user, user, classstr, perm, NULL);
+	if (rc != 0 && user_cxt)
+		*user_cxt = user;
+	else
+		freecon(user);
+
+	return rc == 0 ? 1 : 0;
+}
+
+/* Gets the default context for @path and @st_mode.
+ *
+ * returns 0 on success,
+ *     or <0 on error
+ */
+int ul_selinux_get_default_context(const char *path, int st_mode, char **cxt)
+{
+	struct selabel_handle *hnd;
+	struct selinux_opt options[SELABEL_NOPT] = {};
+	int rc = 0;
+
+	*cxt = NULL;
+
+	hnd = selabel_open(SELABEL_CTX_FILE, options, SELABEL_NOPT);
+	if (!hnd)
+		return -errno;
+
+	if (selabel_lookup(hnd, cxt, path, st_mode) != 0)
+		rc = -errno
+			;
+	selabel_close(hnd);
+
+	return rc;
+}