Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Landlock - Credential hooks
4 *
5 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6 * Copyright © 2018-2020 ANSSI
7 * Copyright © 2024-2025 Microsoft Corporation
8 */
9
10#include <linux/binfmts.h>
11#include <linux/cred.h>
12#include <linux/lsm_hooks.h>
13
14#include "common.h"
15#include "cred.h"
16#include "ruleset.h"
17#include "setup.h"
18
19static void hook_cred_transfer(struct cred *const new,
20 const struct cred *const old)
21{
22 const struct landlock_cred_security *const old_llcred =
23 landlock_cred(old);
24
25 if (old_llcred->domain) {
26 landlock_get_ruleset(old_llcred->domain);
27 *landlock_cred(new) = *old_llcred;
28 }
29}
30
31static int hook_cred_prepare(struct cred *const new,
32 const struct cred *const old, const gfp_t gfp)
33{
34 hook_cred_transfer(new, old);
35 return 0;
36}
37
38static void hook_cred_free(struct cred *const cred)
39{
40 struct landlock_ruleset *const dom = landlock_cred(cred)->domain;
41
42 if (dom)
43 landlock_put_ruleset_deferred(dom);
44}
45
46#ifdef CONFIG_AUDIT
47
48static int hook_bprm_creds_for_exec(struct linux_binprm *const bprm)
49{
50 /* Resets for each execution. */
51 landlock_cred(bprm->cred)->domain_exec = 0;
52 return 0;
53}
54
55#endif /* CONFIG_AUDIT */
56
57static struct security_hook_list landlock_hooks[] __ro_after_init = {
58 LSM_HOOK_INIT(cred_prepare, hook_cred_prepare),
59 LSM_HOOK_INIT(cred_transfer, hook_cred_transfer),
60 LSM_HOOK_INIT(cred_free, hook_cred_free),
61
62#ifdef CONFIG_AUDIT
63 LSM_HOOK_INIT(bprm_creds_for_exec, hook_bprm_creds_for_exec),
64#endif /* CONFIG_AUDIT */
65};
66
67__init void landlock_add_cred_hooks(void)
68{
69 security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
70 &landlock_lsmid);
71}