1 files changed, 71 insertions, 0 deletions
diff --git a/security/landlock/cred.c b/security/landlock/cred.c
new file mode 100644
index 000000000000..0cb3edde4d18
--- /dev/null
+++ b/security/landlock/cred.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock - Credential hooks
+ *
+ * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
+ * Copyright © 2018-2020 ANSSI
+ * Copyright © 2024-2025 Microsoft Corporation
+ */
+
+#include <linux/binfmts.h>
+#include <linux/cred.h>
+#include <linux/lsm_hooks.h>
+
+#include "common.h"
+#include "cred.h"
+#include "ruleset.h"
+#include "setup.h"
+
+static void hook_cred_transfer(struct cred *const new,
+			       const struct cred *const old)
+{
+	const struct landlock_cred_security *const old_llcred =
+		landlock_cred(old);
+
+	if (old_llcred->domain) {
+		landlock_get_ruleset(old_llcred->domain);
+		*landlock_cred(new) = *old_llcred;
+	}
+}
+
+static int hook_cred_prepare(struct cred *const new,
+			     const struct cred *const old, const gfp_t gfp)
+{
+	hook_cred_transfer(new, old);
+	return 0;
+}
+
+static void hook_cred_free(struct cred *const cred)
+{
+	struct landlock_ruleset *const dom = landlock_cred(cred)->domain;
+
+	if (dom)
+		landlock_put_ruleset_deferred(dom);
+}
+
+#ifdef CONFIG_AUDIT
+
+static int hook_bprm_creds_for_exec(struct linux_binprm *const bprm)
+{
+	/* Resets for each execution. */
+	landlock_cred(bprm->cred)->domain_exec = 0;
+	return 0;
+}
+
+#endif /* CONFIG_AUDIT */
+
+static struct security_hook_list landlock_hooks[] __ro_after_init = {
+	LSM_HOOK_INIT(cred_prepare, hook_cred_prepare),
+	LSM_HOOK_INIT(cred_transfer, hook_cred_transfer),
+	LSM_HOOK_INIT(cred_free, hook_cred_free),
+
+#ifdef CONFIG_AUDIT
+	LSM_HOOK_INIT(bprm_creds_for_exec, hook_bprm_creds_for_exec),
+#endif /* CONFIG_AUDIT */
+};
+
+__init void landlock_add_cred_hooks(void)
+{
+	security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
+			   &landlock_lsmid);
+}