[PATCH 5/8] CaitSith: Add LSM adapter functions.

From: Tetsuo Handa
Date: Fri Oct 21 2016 - 08:51:24 EST


This version implements only execve() related LSM hooks.

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
security/caitsith/lsm.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
create mode 100644 security/caitsith/lsm.c

diff --git a/security/caitsith/lsm.c b/security/caitsith/lsm.c
new file mode 100644
index 0000000..675cee8
--- /dev/null
+++ b/security/caitsith/lsm.c
@@ -0,0 +1,60 @@
+/*
+ * security/caitsith/lsm.c
+ *
+ * Copyright (C) 2010-2013 Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/lsm_hooks.h>
+#include "caitsith.h"
+
+/**
+ * caitsith_bprm_set_creds - Target for security_bprm_set_creds().
+ *
+ * @bprm: Pointer to "struct linux_binprm".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int caitsith_bprm_set_creds(struct linux_binprm *bprm)
+{
+ /*
+ * Do only if this function is called for the first time of an execve
+ * operation.
+ */
+ if (bprm->cred_prepared)
+ return 0;
+#ifndef CONFIG_SECURITY_CAITSITH_OMIT_USERSPACE_LOADER
+ /*
+ * Load policy if /sbin/caitsith-init exists and /sbin/init is requested
+ * for the first time.
+ */
+ if (!cs_policy_loaded)
+ cs_load_policy(bprm->filename);
+#endif
+ return cs_start_execve(bprm);
+}
+
+/*
+ * caitsith_security_ops is a "struct security_operations" which is used for
+ * registering CaitSith.
+ */
+static struct security_hook_list caitsith_hooks[] = {
+ LSM_HOOK_INIT(bprm_set_creds, caitsith_bprm_set_creds),
+};
+
+/**
+ * caitsith_init - Register CaitSith as a LSM module.
+ *
+ * Returns 0.
+ */
+static int __init caitsith_init(void)
+{
+ if (!security_module_enable("caitsith"))
+ return 0;
+ /* register ourselves with the security framework */
+ security_add_hooks(caitsith_hooks, ARRAY_SIZE(caitsith_hooks));
+ printk(KERN_INFO "CaitSith initialized\n");
+ cs_init_module();
+ return 0;
+}
+
+security_initcall(caitsith_init);
--
1.8.3.1