1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Landlock LSM - Credential hooks
4 *
5 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6 * Copyright © 2018-2020 ANSSI
7 */
8
9 #include <linux/cred.h>
10 #include <linux/lsm_hooks.h>
11
12 #include "common.h"
13 #include "cred.h"
14 #include "ruleset.h"
15 #include "setup.h"
16
hook_cred_transfer(struct cred * const new,const struct cred * const old)17 static void hook_cred_transfer(struct cred *const new,
18 const struct cred *const old)
19 {
20 struct landlock_ruleset *const old_dom = landlock_cred(old)->domain;
21
22 if (old_dom) {
23 landlock_get_ruleset(old_dom);
24 landlock_cred(new)->domain = old_dom;
25 }
26 }
27
hook_cred_prepare(struct cred * const new,const struct cred * const old,const gfp_t gfp)28 static int hook_cred_prepare(struct cred *const new,
29 const struct cred *const old, const gfp_t gfp)
30 {
31 hook_cred_transfer(new, old);
32 return 0;
33 }
34
hook_cred_free(struct cred * const cred)35 static void hook_cred_free(struct cred *const cred)
36 {
37 struct landlock_ruleset *const dom = landlock_cred(cred)->domain;
38
39 if (dom)
40 landlock_put_ruleset_deferred(dom);
41 }
42
43 static struct security_hook_list landlock_hooks[] __ro_after_init = {
44 LSM_HOOK_INIT(cred_prepare, hook_cred_prepare),
45 LSM_HOOK_INIT(cred_transfer, hook_cred_transfer),
46 LSM_HOOK_INIT(cred_free, hook_cred_free),
47 };
48
landlock_add_cred_hooks(void)49 __init void landlock_add_cred_hooks(void)
50 {
51 security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
52 LANDLOCK_NAME);
53 }
54