1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * SafeSetID Linux Security Module
4  *
5  * Author: Micah Morton <mortonm@chromium.org>
6  *
7  * Copyright (C) 2018 The Chromium OS Authors.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2, as
11  * published by the Free Software Foundation.
12  *
13  */
14 #ifndef _SAFESETID_H
15 #define _SAFESETID_H
16 
17 #include <linux/types.h>
18 #include <linux/uidgid.h>
19 #include <linux/hashtable.h>
20 
21 /* Flag indicating whether initialization completed */
22 extern int safesetid_initialized __initdata;
23 
24 enum sid_policy_type {
25 	SIDPOL_DEFAULT, /* source ID is unaffected by policy */
26 	SIDPOL_CONSTRAINED, /* source ID is affected by policy */
27 	SIDPOL_ALLOWED /* target ID explicitly allowed */
28 };
29 
30 typedef union {
31 	kuid_t uid;
32 	kgid_t gid;
33 } kid_t;
34 
35 enum setid_type {
36 	UID,
37 	GID
38 };
39 
40 /*
41  * Hash table entry to store safesetid policy signifying that 'src_id'
42  * can set*id to 'dst_id'.
43  */
44 struct setid_rule {
45 	struct hlist_node next;
46 	kid_t src_id;
47 	kid_t dst_id;
48 
49 	/* Flag to signal if rule is for UID's or GID's */
50 	enum setid_type type;
51 };
52 
53 #define SETID_HASH_BITS 8 /* 256 buckets in hash table */
54 
55 /* Extension of INVALID_UID/INVALID_GID for kid_t type */
56 #define INVALID_ID (kid_t){.uid = INVALID_UID}
57 
58 struct setid_ruleset {
59 	DECLARE_HASHTABLE(rules, SETID_HASH_BITS);
60 	char *policy_str;
61 	struct rcu_head rcu;
62 
63 	//Flag to signal if ruleset is for UID's or GID's
64 	enum setid_type type;
65 };
66 
67 enum sid_policy_type _setid_policy_lookup(struct setid_ruleset *policy,
68 		kid_t src, kid_t dst);
69 
70 extern struct setid_ruleset __rcu *safesetid_setuid_rules;
71 extern struct setid_ruleset __rcu *safesetid_setgid_rules;
72 
73 #endif /* _SAFESETID_H */
74