security/landlock/cred.c

   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
  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
  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
  42 __init void landlock_add_cred_hooks(void)
  43 {
  44         security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks),
  45                         LANDLOCK_NAME);
  46 }