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_prepare(struct cred * const new,const struct cred * const old,const gfp_t gfp)17 static int hook_cred_prepare(struct cred *const new,
18 			     const struct cred *const old, const gfp_t gfp)
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 	return 0;
27 }
28 
hook_cred_free(struct cred * const cred)29 static void hook_cred_free(struct cred *const cred)
30 {
31 	struct landlock_ruleset *const dom = landlock_cred(cred)->domain;
32 
33 	if (dom)
34 		landlock_put_ruleset_deferred(dom);
35 }
36 
37 static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = {
38 	LSM_HOOK_INIT(cred_prepare, hook_cred_prepare),
39 	LSM_HOOK_INIT(cred_free, hook_cred_free),
40 };
41 
landlock_add_cred_hooks(void)42 __init void landlock_add_cred_hooks(void)
43 {
44 	security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
45 			   LANDLOCK_NAME);
46 }
47