1 /* SPDX-License-Identifier: GPL-2.0 */
3 * A security identifier table (sidtab) is a lookup table
4 * of security context structures indexed by SID value.
6 * Original author: Stephen Smalley, <sds@tycho.nsa.gov>
7 * Author: Ondrej Mosnacek, <omosnacek@gmail.com>
9 * Copyright (C) 2018 Red Hat, Inc.
14 #include <linux/spinlock_types.h>
15 #include <linux/log2.h>
19 struct sidtab_entry_leaf {
20 struct context context;
23 struct sidtab_node_inner;
24 struct sidtab_node_leaf;
26 union sidtab_entry_inner {
27 struct sidtab_node_inner *ptr_inner;
28 struct sidtab_node_leaf *ptr_leaf;
31 /* align node size to page boundary */
32 #define SIDTAB_NODE_ALLOC_SHIFT PAGE_SHIFT
33 #define SIDTAB_NODE_ALLOC_SIZE PAGE_SIZE
35 #define size_to_shift(size) ((size) == 1 ? 1 : (const_ilog2((size) - 1) + 1))
37 #define SIDTAB_INNER_SHIFT \
38 (SIDTAB_NODE_ALLOC_SHIFT - size_to_shift(sizeof(union sidtab_entry_inner)))
39 #define SIDTAB_INNER_ENTRIES ((size_t)1 << SIDTAB_INNER_SHIFT)
40 #define SIDTAB_LEAF_ENTRIES \
41 (SIDTAB_NODE_ALLOC_SIZE / sizeof(struct sidtab_entry_leaf))
43 #define SIDTAB_MAX_BITS 32
44 #define SIDTAB_MAX U32_MAX
45 /* ensure enough tree levels for SIDTAB_MAX entries */
46 #define SIDTAB_MAX_LEVEL \
47 DIV_ROUND_UP(SIDTAB_MAX_BITS - size_to_shift(SIDTAB_LEAF_ENTRIES), \
50 struct sidtab_node_leaf {
51 struct sidtab_entry_leaf entries[SIDTAB_LEAF_ENTRIES];
54 struct sidtab_node_inner {
55 union sidtab_entry_inner entries[SIDTAB_INNER_ENTRIES];
58 struct sidtab_isid_entry {
60 struct context context;
63 struct sidtab_convert_params {
64 int (*func)(struct context *oldc, struct context *newc, void *args);
66 struct sidtab *target;
69 #define SIDTAB_RCACHE_SIZE 3
73 * lock-free read access only for as many items as a prior read of
76 union sidtab_entry_inner roots[SIDTAB_MAX_LEVEL + 1];
78 * access atomically via {READ|WRITE}_ONCE(); only increment under
82 /* access only under spinlock */
83 struct sidtab_convert_params *convert;
86 /* reverse lookup cache - access atomically via {READ|WRITE}_ONCE() */
87 u32 rcache[SIDTAB_RCACHE_SIZE];
89 /* index == SID - 1 (no entry for SECSID_NULL) */
90 struct sidtab_isid_entry isids[SECINITSID_NUM];
93 int sidtab_init(struct sidtab *s);
94 int sidtab_set_initial(struct sidtab *s, u32 sid, struct context *context);
95 struct context *sidtab_search(struct sidtab *s, u32 sid);
96 struct context *sidtab_search_force(struct sidtab *s, u32 sid);
98 int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params);
100 int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid);
102 void sidtab_destroy(struct sidtab *s);
104 #endif /* _SS_SIDTAB_H_ */